video/video_stream_encoder_unittest.cc - src - Git at Google


 /*
  *  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 #include "video/video_stream_encoder.h"

 #include <algorithm>
 #include <limits>
 #include <memory>
 #include <tuple>
 #include <utility>

 #include "absl/memory/memory.h"
 #include "api/field_trials_view.h"
 #include "api/rtp_parameters.h"
 #include "api/task_queue/default_task_queue_factory.h"
 #include "api/task_queue/task_queue_base.h"
 #include "api/task_queue/task_queue_factory.h"
 #include "api/test/mock_fec_controller_override.h"
 #include "api/test/mock_video_encoder.h"
 #include "api/test/mock_video_encoder_factory.h"
 #include "api/units/data_rate.h"
 #include "api/units/time_delta.h"
 #include "api/video/builtin_video_bitrate_allocator_factory.h"
 #include "api/video/i420_buffer.h"
 #include "api/video/nv12_buffer.h"
 #include "api/video/video_adaptation_reason.h"
 #include "api/video/video_bitrate_allocation.h"
 #include "api/video_codecs/sdp_video_format.h"
 #include "api/video_codecs/video_codec.h"
 #include "api/video_codecs/video_encoder.h"
 #include "api/video_codecs/vp8_temporal_layers.h"
 #include "api/video_codecs/vp8_temporal_layers_factory.h"
 #include "call/adaptation/test/fake_adaptation_constraint.h"
 #include "call/adaptation/test/fake_resource.h"
 #include "common_video/h264/h264_common.h"
 #include "common_video/include/video_frame_buffer.h"
 #include "media/base/video_adapter.h"
 #include "media/engine/webrtc_video_engine.h"
 #include "modules/video_coding/codecs/av1/libaom_av1_encoder.h"
 #include "modules/video_coding/codecs/h264/include/h264.h"
 #include "modules/video_coding/codecs/multiplex/include/multiplex_encoder_adapter.h"
 #include "modules/video_coding/codecs/vp8/include/vp8.h"
 #include "modules/video_coding/codecs/vp9/include/vp9.h"
 #include "modules/video_coding/codecs/vp9/include/vp9_globals.h"
 #include "modules/video_coding/codecs/vp9/svc_config.h"
 #include "modules/video_coding/utility/quality_scaler.h"
 #include "modules/video_coding/utility/simulcast_rate_allocator.h"
 #include "modules/video_coding/utility/vp8_constants.h"
 #include "rtc_base/event.h"
 #include "rtc_base/experiments/encoder_info_settings.h"
 #include "rtc_base/gunit.h"
 #include "rtc_base/logging.h"
 #include "rtc_base/ref_counted_object.h"
 #include "rtc_base/synchronization/mutex.h"
 #include "system_wrappers/include/metrics.h"
 #include "test/encoder_settings.h"
 #include "test/fake_encoder.h"
 #include "test/frame_forwarder.h"
 #include "test/gmock.h"
 #include "test/gtest.h"
 #include "test/mappable_native_buffer.h"
 #include "test/scoped_key_value_config.h"
 #include "test/time_controller/simulated_time_controller.h"
 #include "test/video_encoder_nullable_proxy_factory.h"
 #include "test/video_encoder_proxy_factory.h"
 #include "video/config/encoder_stream_factory.h"
 #include "video/frame_cadence_adapter.h"
 #include "video/send_statistics_proxy.h"

 namespace webrtc {

 using ::testing::_;
 using ::testing::AllOf;
 using ::testing::Eq;
 using ::testing::Field;
 using ::testing::Ge;
 using ::testing::Gt;
 using ::testing::Invoke;
 using ::testing::Le;
 using ::testing::Lt;
 using ::testing::Matcher;
 using ::testing::Mock;
 using ::testing::NiceMock;
 using ::testing::Optional;
 using ::testing::Return;
 using ::testing::SizeIs;
 using ::testing::StrictMock;

 namespace {
 const int kMinPixelsPerFrame = 320 * 180;
 const int kQpLow = 1;
 const int kQpHigh = 2;
 const int kMinFramerateFps = 2;
 const int kMinBalancedFramerateFps = 7;
 constexpr TimeDelta kFrameTimeout = TimeDelta::Millis(100);
 const size_t kMaxPayloadLength = 1440;
 const DataRate kTargetBitrate = DataRate::KilobitsPerSec(1000);
 const DataRate kLowTargetBitrate = DataRate::KilobitsPerSec(100);
 const DataRate kStartBitrate = DataRate::KilobitsPerSec(600);
 const DataRate kSimulcastTargetBitrate = DataRate::KilobitsPerSec(3150);
 const int kMaxInitialFramedrop = 4;
 const int kDefaultFramerate = 30;
 const int64_t kFrameIntervalMs = rtc::kNumMillisecsPerSec / kDefaultFramerate;
 const int64_t kProcessIntervalMs = 1000;
 const VideoEncoder::ResolutionBitrateLimits
     kEncoderBitrateLimits540p(960 * 540, 100 * 1000, 100 * 1000, 2000 * 1000);
 const VideoEncoder::ResolutionBitrateLimits
     kEncoderBitrateLimits720p(1280 * 720, 200 * 1000, 200 * 1000, 4000 * 1000);

 uint8_t kOptimalSps[] = {0,    0,    0,    1,    H264::NaluType::kSps,
                          0x00, 0x00, 0x03, 0x03, 0xF4,
                          0x05, 0x03, 0xC7, 0xE0, 0x1B,
                          0x41, 0x10, 0x8D, 0x00};

 const uint8_t kCodedFrameVp8Qp25[] = {
     0x10, 0x02, 0x00, 0x9d, 0x01, 0x2a, 0x10, 0x00, 0x10, 0x00,
     0x02, 0x47, 0x08, 0x85, 0x85, 0x88, 0x85, 0x84, 0x88, 0x0c,
     0x82, 0x00, 0x0c, 0x0d, 0x60, 0x00, 0xfe, 0xfc, 0x5c, 0xd0};

 VideoFrame CreateSimpleNV12Frame() {
   return VideoFrame::Builder()
       .set_video_frame_buffer(rtc::make_ref_counted<NV12Buffer>(
           /*width=*/16, /*height=*/16))
       .build();
 }

 void PassAFrame(
     TaskQueueBase* encoder_queue,
     FrameCadenceAdapterInterface::Callback* video_stream_encoder_callback,
     int64_t ntp_time_ms) {
   encoder_queue->PostTask([video_stream_encoder_callback, ntp_time_ms] {
     video_stream_encoder_callback->OnFrame(Timestamp::Millis(ntp_time_ms),
                                            false, CreateSimpleNV12Frame());
   });
 }

 class TestBuffer : public webrtc::I420Buffer {
  public:
   TestBuffer(rtc::Event* event, int width, int height)
       : I420Buffer(width, height), event_(event) {}

  private:
   friend class rtc::RefCountedObject<TestBuffer>;
   ~TestBuffer() override {
     if (event_)
       event_->Set();
   }
   rtc::Event* const event_;
 };

 // A fake native buffer that can't be converted to I420. Upon scaling, it
 // produces another FakeNativeBuffer.
 class FakeNativeBuffer : public webrtc::VideoFrameBuffer {
  public:
   FakeNativeBuffer(rtc::Event* event, int width, int height)
       : event_(event), width_(width), height_(height) {}
   webrtc::VideoFrameBuffer::Type type() const override { return Type::kNative; }
   int width() const override { return width_; }
   int height() const override { return height_; }
   rtc::scoped_refptr<webrtc::I420BufferInterface> ToI420() override {
     return nullptr;
   }
   rtc::scoped_refptr<VideoFrameBuffer> CropAndScale(
       int offset_x,
       int offset_y,
       int crop_width,
       int crop_height,
       int scaled_width,
       int scaled_height) override {
     return rtc::make_ref_counted<FakeNativeBuffer>(nullptr, scaled_width,
                                                    scaled_height);
   }

  private:
   friend class rtc::RefCountedObject<FakeNativeBuffer>;
   ~FakeNativeBuffer() override {
     if (event_)
       event_->Set();
   }
   rtc::Event* const event_;
   const int width_;
   const int height_;
 };

 // A fake native buffer that is backed by an NV12 buffer.
 class FakeNV12NativeBuffer : public webrtc::VideoFrameBuffer {
  public:
   FakeNV12NativeBuffer(rtc::Event* event, int width, int height)
       : nv12_buffer_(NV12Buffer::Create(width, height)), event_(event) {}

   webrtc::VideoFrameBuffer::Type type() const override { return Type::kNative; }
   int width() const override { return nv12_buffer_->width(); }
   int height() const override { return nv12_buffer_->height(); }
   rtc::scoped_refptr<webrtc::I420BufferInterface> ToI420() override {
     return nv12_buffer_->ToI420();
   }
   rtc::scoped_refptr<VideoFrameBuffer> GetMappedFrameBuffer(
       rtc::ArrayView<VideoFrameBuffer::Type> types) override {
     if (absl::c_find(types, Type::kNV12) != types.end()) {
       return nv12_buffer_;
     }
     return nullptr;
   }
   const NV12BufferInterface* GetNV12() const { return nv12_buffer_.get(); }

  private:
   friend class rtc::RefCountedObject<FakeNV12NativeBuffer>;
   ~FakeNV12NativeBuffer() override {
     if (event_)
       event_->Set();
   }
   rtc::scoped_refptr<NV12Buffer> nv12_buffer_;
   rtc::Event* const event_;
 };

 class CpuOveruseDetectorProxy : public OveruseFrameDetector {
  public:
   explicit CpuOveruseDetectorProxy(CpuOveruseMetricsObserver* metrics_observer)
       : OveruseFrameDetector(metrics_observer),
         last_target_framerate_fps_(-1),
         framerate_updated_event_(true /* manual_reset */,
                                  false /* initially_signaled */) {}
   virtual ~CpuOveruseDetectorProxy() {}

   void OnTargetFramerateUpdated(int framerate_fps) override {
     MutexLock lock(&lock_);
     last_target_framerate_fps_ = framerate_fps;
     OveruseFrameDetector::OnTargetFramerateUpdated(framerate_fps);
     framerate_updated_event_.Set();
   }

   int GetLastTargetFramerate() {
     MutexLock lock(&lock_);
     return last_target_framerate_fps_;
   }

   CpuOveruseOptions GetOptions() { return options_; }

   rtc::Event* framerate_updated_event() { return &framerate_updated_event_; }

  private:
   Mutex lock_;
   int last_target_framerate_fps_ RTC_GUARDED_BY(lock_);
   rtc::Event framerate_updated_event_;
 };

 class FakeVideoSourceRestrictionsListener
     : public VideoSourceRestrictionsListener {
  public:
   FakeVideoSourceRestrictionsListener()
       : was_restrictions_updated_(false), restrictions_updated_event_() {}
   ~FakeVideoSourceRestrictionsListener() override {
     RTC_DCHECK(was_restrictions_updated_);
   }

   rtc::Event* restrictions_updated_event() {
     return &restrictions_updated_event_;
   }

   // VideoSourceRestrictionsListener implementation.
   void OnVideoSourceRestrictionsUpdated(
       VideoSourceRestrictions restrictions,
       const VideoAdaptationCounters& adaptation_counters,
       rtc::scoped_refptr<Resource> reason,
       const VideoSourceRestrictions& unfiltered_restrictions) override {
     was_restrictions_updated_ = true;
     restrictions_updated_event_.Set();
   }

  private:
   bool was_restrictions_updated_;
   rtc::Event restrictions_updated_event_;
 };

 auto WantsFps(Matcher<int> fps_matcher) {
   return Field("max_framerate_fps", &rtc::VideoSinkWants::max_framerate_fps,
                fps_matcher);
 }

 auto WantsMaxPixels(Matcher<int> max_pixel_matcher) {
   return Field("max_pixel_count", &rtc::VideoSinkWants::max_pixel_count,
                AllOf(max_pixel_matcher, Gt(0)));
 }

 auto ResolutionMax() {
   return AllOf(
       WantsMaxPixels(Eq(std::numeric_limits<int>::max())),
       Field("target_pixel_count", &rtc::VideoSinkWants::target_pixel_count,
             Eq(absl::nullopt)));
 }

 auto FpsMax() {
   return WantsFps(Eq(kDefaultFramerate));
 }

 auto FpsUnlimited() {
   return WantsFps(Eq(std::numeric_limits<int>::max()));
 }

 auto FpsMatchesResolutionMax(Matcher<int> fps_matcher) {
   return AllOf(WantsFps(fps_matcher), ResolutionMax());
 }

 auto FpsMaxResolutionMatches(Matcher<int> pixel_matcher) {
   return AllOf(FpsMax(), WantsMaxPixels(pixel_matcher));
 }

 auto FpsMaxResolutionMax() {
   return AllOf(FpsMax(), ResolutionMax());
 }

 auto UnlimitedSinkWants() {
   return AllOf(FpsUnlimited(), ResolutionMax());
 }

 auto FpsInRangeForPixelsInBalanced(int last_frame_pixels) {
   Matcher<int> fps_range_matcher;

   if (last_frame_pixels <= 320 * 240) {
     fps_range_matcher = AllOf(Ge(7), Le(10));
   } else if (last_frame_pixels <= 480 * 360) {
     fps_range_matcher = AllOf(Ge(10), Le(15));
   } else if (last_frame_pixels <= 640 * 480) {
     fps_range_matcher = Ge(15);
   } else {
     fps_range_matcher = Eq(kDefaultFramerate);
   }
   return Field("max_framerate_fps", &rtc::VideoSinkWants::max_framerate_fps,
                fps_range_matcher);
 }

 auto FpsEqResolutionEqTo(const rtc::VideoSinkWants& other_wants) {
   return AllOf(WantsFps(Eq(other_wants.max_framerate_fps)),
                WantsMaxPixels(Eq(other_wants.max_pixel_count)));
 }

 auto FpsMaxResolutionLt(const rtc::VideoSinkWants& other_wants) {
   return AllOf(FpsMax(), WantsMaxPixels(Lt(other_wants.max_pixel_count)));
 }

 auto FpsMaxResolutionGt(const rtc::VideoSinkWants& other_wants) {
   return AllOf(FpsMax(), WantsMaxPixels(Gt(other_wants.max_pixel_count)));
 }

 auto FpsLtResolutionEq(const rtc::VideoSinkWants& other_wants) {
   return AllOf(WantsFps(Lt(other_wants.max_framerate_fps)),
                WantsMaxPixels(Eq(other_wants.max_pixel_count)));
 }

 auto FpsGtResolutionEq(const rtc::VideoSinkWants& other_wants) {
   return AllOf(WantsFps(Gt(other_wants.max_framerate_fps)),
                WantsMaxPixels(Eq(other_wants.max_pixel_count)));
 }

 auto FpsEqResolutionLt(const rtc::VideoSinkWants& other_wants) {
   return AllOf(WantsFps(Eq(other_wants.max_framerate_fps)),
                WantsMaxPixels(Lt(other_wants.max_pixel_count)));
 }

 auto FpsEqResolutionGt(const rtc::VideoSinkWants& other_wants) {
   return AllOf(WantsFps(Eq(other_wants.max_framerate_fps)),
                WantsMaxPixels(Gt(other_wants.max_pixel_count)));
 }

 class VideoStreamEncoderUnderTest : public VideoStreamEncoder {
  public:
   VideoStreamEncoderUnderTest(
       TimeController* time_controller,
       std::unique_ptr<FrameCadenceAdapterInterface> cadence_adapter,
       std::unique_ptr<webrtc::TaskQueueBase, webrtc::TaskQueueDeleter>
           encoder_queue,
       SendStatisticsProxy* stats_proxy,
       const VideoStreamEncoderSettings& settings,
       VideoStreamEncoder::BitrateAllocationCallbackType
           allocation_callback_type,
       const FieldTrialsView& field_trials,
       int num_cores)
       : VideoStreamEncoder(time_controller->GetClock(),
                            num_cores,
                            stats_proxy,
                            settings,
                            std::unique_ptr<OveruseFrameDetector>(
                                overuse_detector_proxy_ =
                                    new CpuOveruseDetectorProxy(stats_proxy)),
                            std::move(cadence_adapter),
                            std::move(encoder_queue),
                            allocation_callback_type,
                            field_trials),
         time_controller_(time_controller),
         fake_cpu_resource_(FakeResource::Create("FakeResource[CPU]")),
         fake_quality_resource_(FakeResource::Create("FakeResource[QP]")),
         fake_adaptation_constraint_("FakeAdaptationConstraint") {
     InjectAdaptationResource(fake_quality_resource_,
                              VideoAdaptationReason::kQuality);
     InjectAdaptationResource(fake_cpu_resource_, VideoAdaptationReason::kCpu);
     InjectAdaptationConstraint(&fake_adaptation_constraint_);
   }

   void SetSourceAndWaitForRestrictionsUpdated(
       rtc::VideoSourceInterface<VideoFrame>* source,
       const DegradationPreference& degradation_preference) {
     FakeVideoSourceRestrictionsListener listener;
     AddRestrictionsListenerForTesting(&listener);
     SetSource(source, degradation_preference);
     listener.restrictions_updated_event()->Wait(TimeDelta::Seconds(5));
     RemoveRestrictionsListenerForTesting(&listener);
   }

   void SetSourceAndWaitForFramerateUpdated(
       rtc::VideoSourceInterface<VideoFrame>* source,
       const DegradationPreference& degradation_preference) {
     overuse_detector_proxy_->framerate_updated_event()->Reset();
     SetSource(source, degradation_preference);
     overuse_detector_proxy_->framerate_updated_event()->Wait(
         TimeDelta::Seconds(5));
   }

   void OnBitrateUpdatedAndWaitForManagedResources(
       DataRate target_bitrate,
       DataRate stable_target_bitrate,
       DataRate link_allocation,
       uint8_t fraction_lost,
       int64_t round_trip_time_ms,
       double cwnd_reduce_ratio) {
     OnBitrateUpdated(target_bitrate, stable_target_bitrate, link_allocation,
                      fraction_lost, round_trip_time_ms, cwnd_reduce_ratio);
     // Bitrate is updated on the encoder queue.
     WaitUntilTaskQueueIsIdle();
   }

   // This is used as a synchronisation mechanism, to make sure that the
   // encoder queue is not blocked before we start sending it frames.
   void WaitUntilTaskQueueIsIdle() {
     time_controller_->AdvanceTime(TimeDelta::Zero());
   }

   // Triggers resource usage measurements on the fake CPU resource.
   void TriggerCpuOveruse() {
     rtc::Event event;
     encoder_queue()->PostTask([this, &event] {
       fake_cpu_resource_->SetUsageState(ResourceUsageState::kOveruse);
       event.Set();
     });
     ASSERT_TRUE(event.Wait(TimeDelta::Seconds(5)));
     time_controller_->AdvanceTime(TimeDelta::Zero());
   }

   void TriggerCpuUnderuse() {
     rtc::Event event;
     encoder_queue()->PostTask([this, &event] {
       fake_cpu_resource_->SetUsageState(ResourceUsageState::kUnderuse);
       event.Set();
     });
     ASSERT_TRUE(event.Wait(TimeDelta::Seconds(5)));
     time_controller_->AdvanceTime(TimeDelta::Zero());
   }

   // Triggers resource usage measurements on the fake quality resource.
   void TriggerQualityLow() {
     rtc::Event event;
     encoder_queue()->PostTask([this, &event] {
       fake_quality_resource_->SetUsageState(ResourceUsageState::kOveruse);
       event.Set();
     });
     ASSERT_TRUE(event.Wait(TimeDelta::Seconds(5)));
     time_controller_->AdvanceTime(TimeDelta::Zero());
   }
   void TriggerQualityHigh() {
     rtc::Event event;
     encoder_queue()->PostTask([this, &event] {
       fake_quality_resource_->SetUsageState(ResourceUsageState::kUnderuse);
       event.Set();
     });
     ASSERT_TRUE(event.Wait(TimeDelta::Seconds(5)));
     time_controller_->AdvanceTime(TimeDelta::Zero());
   }

   TimeController* const time_controller_;
   CpuOveruseDetectorProxy* overuse_detector_proxy_;
   rtc::scoped_refptr<FakeResource> fake_cpu_resource_;
   rtc::scoped_refptr<FakeResource> fake_quality_resource_;
   FakeAdaptationConstraint fake_adaptation_constraint_;
 };

 // Simulates simulcast behavior and makes highest stream resolutions divisible
 // by 4.
 class CroppingVideoStreamFactory
     : public VideoEncoderConfig::VideoStreamFactoryInterface {
  public:
   CroppingVideoStreamFactory() {}

  private:
   std::vector<VideoStream> CreateEncoderStreams(
       int frame_width,
       int frame_height,
       const VideoEncoderConfig& encoder_config) override {
     std::vector<VideoStream> streams = test::CreateVideoStreams(
         frame_width - frame_width % 4, frame_height - frame_height % 4,
         encoder_config);
     return streams;
   }
 };

 class AdaptingFrameForwarder : public test::FrameForwarder {
  public:
   explicit AdaptingFrameForwarder(TimeController* time_controller)
       : time_controller_(time_controller), adaptation_enabled_(false) {}
   ~AdaptingFrameForwarder() override {}

   void set_adaptation_enabled(bool enabled) {
     MutexLock lock(&mutex_);
     adaptation_enabled_ = enabled;
   }

   bool adaption_enabled() const {
     MutexLock lock(&mutex_);
     return adaptation_enabled_;
   }

   // The "last wants" is a snapshot of the previous rtc::VideoSinkWants where
   // the resolution or frame rate was different than it is currently. If
   // something else is modified, such as encoder resolutions, but the resolution
   // and frame rate stays the same, last wants is not updated.
   rtc::VideoSinkWants last_wants() const {
     MutexLock lock(&mutex_);
     return last_wants_;
   }

   absl::optional<int> last_sent_width() const { return last_width_; }
   absl::optional<int> last_sent_height() const { return last_height_; }

   void IncomingCapturedFrame(const VideoFrame& video_frame) override {
     RTC_DCHECK(time_controller_->GetMainThread()->IsCurrent());
     time_controller_->AdvanceTime(TimeDelta::Zero());

     int cropped_width = 0;
     int cropped_height = 0;
     int out_width = 0;
     int out_height = 0;
     if (adaption_enabled()) {
       RTC_DLOG(LS_INFO) << "IncomingCapturedFrame: AdaptFrameResolution()"
                         << "w=" << video_frame.width()
                         << "h=" << video_frame.height();
       if (adapter_.AdaptFrameResolution(
               video_frame.width(), video_frame.height(),
               video_frame.timestamp_us() * 1000, &cropped_width,
               &cropped_height, &out_width, &out_height)) {
         VideoFrame adapted_frame =
             VideoFrame::Builder()
                 .set_video_frame_buffer(rtc::make_ref_counted<TestBuffer>(
                     nullptr, out_width, out_height))
                 .set_ntp_time_ms(video_frame.ntp_time_ms())
                 .set_timestamp_ms(99)
                 .set_rotation(kVideoRotation_0)
                 .build();
         if (video_frame.has_update_rect()) {
           adapted_frame.set_update_rect(
               video_frame.update_rect().ScaleWithFrame(
                   video_frame.width(), video_frame.height(), 0, 0,
                   video_frame.width(), video_frame.height(), out_width,
                   out_height));
         }
         test::FrameForwarder::IncomingCapturedFrame(adapted_frame);
         last_width_.emplace(adapted_frame.width());
         last_height_.emplace(adapted_frame.height());
       } else {
         last_width_ = absl::nullopt;
         last_height_ = absl::nullopt;
       }
     } else {
       RTC_DLOG(LS_INFO) << "IncomingCapturedFrame: adaptation not enabled";
       test::FrameForwarder::IncomingCapturedFrame(video_frame);
       last_width_.emplace(video_frame.width());
       last_height_.emplace(video_frame.height());
     }
   }

   void OnOutputFormatRequest(int width, int height) {
     absl::optional<std::pair<int, int>> target_aspect_ratio =
         std::make_pair(width, height);
     absl::optional<int> max_pixel_count = width * height;
     absl::optional<int> max_fps;
     adapter_.OnOutputFormatRequest(target_aspect_ratio, max_pixel_count,
                                    max_fps);
   }

   void AddOrUpdateSink(rtc::VideoSinkInterface<VideoFrame>* sink,
                        const rtc::VideoSinkWants& wants) override {
     MutexLock lock(&mutex_);
     rtc::VideoSinkWants prev_wants = sink_wants_locked();
     bool did_adapt =
         prev_wants.max_pixel_count != wants.max_pixel_count ||
         prev_wants.target_pixel_count != wants.target_pixel_count ||
         prev_wants.max_framerate_fps != wants.max_framerate_fps;
     if (did_adapt) {
       last_wants_ = prev_wants;
     }
     adapter_.OnSinkWants(wants);
     test::FrameForwarder::AddOrUpdateSinkLocked(sink, wants);
   }

   void RequestRefreshFrame() override { ++refresh_frames_requested_; }

   TimeController* const time_controller_;
   cricket::VideoAdapter adapter_;
   bool adaptation_enabled_ RTC_GUARDED_BY(mutex_);
   rtc::VideoSinkWants last_wants_ RTC_GUARDED_BY(mutex_);
   absl::optional<int> last_width_;
   absl::optional<int> last_height_;
   int refresh_frames_requested_{0};
 };

 // TODO(nisse): Mock only VideoStreamEncoderObserver.
 class MockableSendStatisticsProxy : public SendStatisticsProxy {
  public:
   MockableSendStatisticsProxy(Clock* clock,
                               const VideoSendStream::Config& config,
                               VideoEncoderConfig::ContentType content_type,
                               const FieldTrialsView& field_trials)
       : SendStatisticsProxy(clock, config, content_type, field_trials) {}

   VideoSendStream::Stats GetStats() override {
     MutexLock lock(&lock_);
     if (mock_stats_)
       return *mock_stats_;
     return SendStatisticsProxy::GetStats();
   }

   int GetInputFrameRate() const override {
     MutexLock lock(&lock_);
     if (mock_stats_)
       return mock_stats_->input_frame_rate;
     return SendStatisticsProxy::GetInputFrameRate();
   }
   void SetMockStats(const VideoSendStream::Stats& stats) {
     MutexLock lock(&lock_);
     mock_stats_.emplace(stats);
   }

   void ResetMockStats() {
     MutexLock lock(&lock_);
     mock_stats_.reset();
   }

   void SetDroppedFrameCallback(std::function<void(DropReason)> callback) {
     on_frame_dropped_ = std::move(callback);
   }

  private:
   void OnFrameDropped(DropReason reason) override {
     SendStatisticsProxy::OnFrameDropped(reason);
     if (on_frame_dropped_)
       on_frame_dropped_(reason);
   }

   mutable Mutex lock_;
   absl::optional<VideoSendStream::Stats> mock_stats_ RTC_GUARDED_BY(lock_);
   std::function<void(DropReason)> on_frame_dropped_;
 };

 class SimpleVideoStreamEncoderFactory {
  public:
   class AdaptedVideoStreamEncoder : public VideoStreamEncoder {
    public:
     using VideoStreamEncoder::VideoStreamEncoder;
     ~AdaptedVideoStreamEncoder() { Stop(); }
   };

   class MockFakeEncoder : public test::FakeEncoder {
    public:
     using FakeEncoder::FakeEncoder;
     MOCK_METHOD(CodecSpecificInfo,
                 EncodeHook,
                 (EncodedImage & encoded_image,
                  rtc::scoped_refptr<EncodedImageBuffer> buffer),
                 (override));
   };

   SimpleVideoStreamEncoderFactory() {
     encoder_settings_.encoder_factory = &encoder_factory_;
     encoder_settings_.bitrate_allocator_factory =
         bitrate_allocator_factory_.get();
   }

   std::unique_ptr<AdaptedVideoStreamEncoder> CreateWithEncoderQueue(
       std::unique_ptr<FrameCadenceAdapterInterface> zero_hertz_adapter,
       std::unique_ptr<TaskQueueBase, TaskQueueDeleter> encoder_queue,
       const FieldTrialsView* field_trials = nullptr) {
     auto result = std::make_unique<AdaptedVideoStreamEncoder>(
         time_controller_.GetClock(),
         /*number_of_cores=*/1,
         /*stats_proxy=*/stats_proxy_.get(), encoder_settings_,
         std::make_unique<CpuOveruseDetectorProxy>(
             /*stats_proxy=*/nullptr),
         std::move(zero_hertz_adapter), std::move(encoder_queue),
         VideoStreamEncoder::BitrateAllocationCallbackType::
             kVideoBitrateAllocation,
         field_trials ? *field_trials : field_trials_);
     result->SetSink(&sink_, /*rotation_applied=*/false);
     return result;
   }

   std::unique_ptr<AdaptedVideoStreamEncoder> Create(
       std::unique_ptr<FrameCadenceAdapterInterface> zero_hertz_adapter,
       TaskQueueBase** encoder_queue_ptr = nullptr) {
     auto encoder_queue =
         time_controller_.GetTaskQueueFactory()->CreateTaskQueue(
             "EncoderQueue", TaskQueueFactory::Priority::NORMAL);
     if (encoder_queue_ptr)
       *encoder_queue_ptr = encoder_queue.get();
     return CreateWithEncoderQueue(std::move(zero_hertz_adapter),
                                   std::move(encoder_queue));
   }

   void DepleteTaskQueues() { time_controller_.AdvanceTime(TimeDelta::Zero()); }
   MockFakeEncoder& GetMockFakeEncoder() { return mock_fake_encoder_; }

   GlobalSimulatedTimeController* GetTimeController() {
     return &time_controller_;
   }

  private:
   class NullEncoderSink : public VideoStreamEncoderInterface::EncoderSink {
    public:
     ~NullEncoderSink() override = default;
     void OnEncoderConfigurationChanged(
         std::vector<VideoStream> streams,
         bool is_svc,
         VideoEncoderConfig::ContentType content_type,
         int min_transmit_bitrate_bps) override {}
     void OnBitrateAllocationUpdated(
         const VideoBitrateAllocation& allocation) override {}
     void OnVideoLayersAllocationUpdated(
         VideoLayersAllocation allocation) override {}
     Result OnEncodedImage(
         const EncodedImage& encoded_image,
         const CodecSpecificInfo* codec_specific_info) override {
       return Result(EncodedImageCallback::Result::OK);
     }
   };

   test::ScopedKeyValueConfig field_trials_;
   GlobalSimulatedTimeController time_controller_{Timestamp::Zero()};
   std::unique_ptr<TaskQueueFactory> task_queue_factory_{
       time_controller_.CreateTaskQueueFactory()};
   std::unique_ptr<MockableSendStatisticsProxy> stats_proxy_ =
       std::make_unique<MockableSendStatisticsProxy>(
           time_controller_.GetClock(),
           VideoSendStream::Config(nullptr),
           webrtc::VideoEncoderConfig::ContentType::kRealtimeVideo,
           field_trials_);
   std::unique_ptr<VideoBitrateAllocatorFactory> bitrate_allocator_factory_ =
       CreateBuiltinVideoBitrateAllocatorFactory();
   VideoStreamEncoderSettings encoder_settings_{
       VideoEncoder::Capabilities(/*loss_notification=*/false)};
   MockFakeEncoder mock_fake_encoder_{time_controller_.GetClock()};
   test::VideoEncoderProxyFactory encoder_factory_{&mock_fake_encoder_};
   NullEncoderSink sink_;
 };

 class MockFrameCadenceAdapter : public FrameCadenceAdapterInterface {
  public:
   MOCK_METHOD(void, Initialize, (Callback * callback), (override));
   MOCK_METHOD(void,
               SetZeroHertzModeEnabled,
               (absl::optional<ZeroHertzModeParams>),
               (override));
   MOCK_METHOD(void, OnFrame, (const VideoFrame&), (override));
   MOCK_METHOD(absl::optional<uint32_t>, GetInputFrameRateFps, (), (override));
   MOCK_METHOD(void, UpdateFrameRate, (), (override));
   MOCK_METHOD(void,
               UpdateLayerQualityConvergence,
               (size_t spatial_index, bool converged),
               (override));
   MOCK_METHOD(void,
               UpdateLayerStatus,
               (size_t spatial_index, bool enabled),
               (override));
   MOCK_METHOD(void,
               UpdateVideoSourceRestrictions,
               (absl::optional<double>),
               (override));
   MOCK_METHOD(void, ProcessKeyFrameRequest, (), (override));
 };

 class MockEncoderSelector
     : public VideoEncoderFactory::EncoderSelectorInterface {
  public:
   MOCK_METHOD(void,
               OnCurrentEncoder,
               (const SdpVideoFormat& format),
               (override));
   MOCK_METHOD(absl::optional<SdpVideoFormat>,
               OnAvailableBitrate,
               (const DataRate& rate),
               (override));
   MOCK_METHOD(absl::optional<SdpVideoFormat>,
               OnResolutionChange,
               (const RenderResolution& resolution),
               (override));
   MOCK_METHOD(absl::optional<SdpVideoFormat>, OnEncoderBroken, (), (override));
 };

 class MockVideoSourceInterface : public rtc::VideoSourceInterface<VideoFrame> {
  public:
   MOCK_METHOD(void,
               AddOrUpdateSink,
               (rtc::VideoSinkInterface<VideoFrame>*,
                const rtc::VideoSinkWants&),
               (override));
   MOCK_METHOD(void,
               RemoveSink,
               (rtc::VideoSinkInterface<VideoFrame>*),
               (override));
   MOCK_METHOD(void, RequestRefreshFrame, (), (override));
 };

 }  // namespace

 class VideoStreamEncoderTest : public ::testing::Test {
  public:
   static constexpr TimeDelta kDefaultTimeout = TimeDelta::Seconds(1);

   VideoStreamEncoderTest()
       : video_send_config_(VideoSendStream::Config(nullptr)),
         codec_width_(320),
         codec_height_(240),
         max_framerate_(kDefaultFramerate),
         fake_encoder_(&time_controller_),
         encoder_factory_(&fake_encoder_),
         stats_proxy_(new MockableSendStatisticsProxy(
             time_controller_.GetClock(),
             video_send_config_,
             webrtc::VideoEncoderConfig::ContentType::kRealtimeVideo,
             field_trials_)),
         sink_(&time_controller_, &fake_encoder_) {}

   void SetUp() override {
     metrics::Reset();
     video_send_config_ = VideoSendStream::Config(nullptr);
     video_send_config_.encoder_settings.encoder_factory = &encoder_factory_;
     video_send_config_.encoder_settings.bitrate_allocator_factory =
         &bitrate_allocator_factory_;
     video_send_config_.rtp.payload_name = "FAKE";
     video_send_config_.rtp.payload_type = 125;

     VideoEncoderConfig video_encoder_config;
     test::FillEncoderConfiguration(kVideoCodecVP8, 1, &video_encoder_config);
     EXPECT_EQ(1u, video_encoder_config.simulcast_layers.size());
     video_encoder_config.simulcast_layers[0].num_temporal_layers = 1;
     video_encoder_config.simulcast_layers[0].max_framerate = max_framerate_;
     video_encoder_config_ = video_encoder_config.Copy();

     ConfigureEncoder(std::move(video_encoder_config));
   }

   void ConfigureEncoder(
       VideoEncoderConfig video_encoder_config,
       VideoStreamEncoder::BitrateAllocationCallbackType
           allocation_callback_type =
               VideoStreamEncoder::BitrateAllocationCallbackType::
                   kVideoBitrateAllocationWhenScreenSharing,
       int num_cores = 1) {
     if (video_stream_encoder_)
       video_stream_encoder_->Stop();

     auto encoder_queue = GetTaskQueueFactory()->CreateTaskQueue(
         "EncoderQueue", TaskQueueFactory::Priority::NORMAL);
     TaskQueueBase* encoder_queue_ptr = encoder_queue.get();
     std::unique_ptr<FrameCadenceAdapterInterface> cadence_adapter =
         FrameCadenceAdapterInterface::Create(time_controller_.GetClock(),
                                              encoder_queue_ptr, field_trials_);
     video_stream_encoder_ = std::make_unique<VideoStreamEncoderUnderTest>(
         &time_controller_, std::move(cadence_adapter), std::move(encoder_queue),
         stats_proxy_.get(), video_send_config_.encoder_settings,
         allocation_callback_type, field_trials_, num_cores);
     video_stream_encoder_->SetSink(&sink_, /*rotation_applied=*/false);
     video_stream_encoder_->SetSource(
         &video_source_, webrtc::DegradationPreference::MAINTAIN_FRAMERATE);
     video_stream_encoder_->SetStartBitrate(kTargetBitrate.bps());
     video_stream_encoder_->ConfigureEncoder(std::move(video_encoder_config),
                                             kMaxPayloadLength, nullptr);
     video_stream_encoder_->WaitUntilTaskQueueIsIdle();
   }

   void ResetEncoder(const std::string& payload_name,
                     size_t num_streams,
                     size_t num_temporal_layers,
                     unsigned char num_spatial_layers,
                     bool screenshare,
                     VideoStreamEncoder::BitrateAllocationCallbackType
                         allocation_callback_type =
                             VideoStreamEncoder::BitrateAllocationCallbackType::
                                 kVideoBitrateAllocationWhenScreenSharing,
                     int num_cores = 1) {
     video_send_config_.rtp.payload_name = payload_name;

     VideoEncoderConfig video_encoder_config;
     test::FillEncoderConfiguration(PayloadStringToCodecType(payload_name),
                                    num_streams, &video_encoder_config);
     for (auto& layer : video_encoder_config.simulcast_layers) {
       layer.num_temporal_layers = num_temporal_layers;
       layer.max_framerate = kDefaultFramerate;
     }
     video_encoder_config.max_bitrate_bps =
         num_streams == 1 ? kTargetBitrate.bps() : kSimulcastTargetBitrate.bps();
     video_encoder_config.content_type =
         screenshare ? VideoEncoderConfig::ContentType::kScreen
                     : VideoEncoderConfig::ContentType::kRealtimeVideo;
     if (payload_name == "VP9") {
       VideoCodecVP9 vp9_settings = VideoEncoder::GetDefaultVp9Settings();
       vp9_settings.numberOfSpatialLayers = num_spatial_layers;
       vp9_settings.automaticResizeOn = num_spatial_layers <= 1;
       video_encoder_config.encoder_specific_settings =
           rtc::make_ref_counted<VideoEncoderConfig::Vp9EncoderSpecificSettings>(
               vp9_settings);
     }
     ConfigureEncoder(std::move(video_encoder_config), allocation_callback_type,
                      num_cores);
   }

   VideoFrame CreateFrame(int64_t ntp_time_ms,
                          rtc::Event* destruction_event) const {
     return VideoFrame::Builder()
         .set_video_frame_buffer(rtc::make_ref_counted<TestBuffer>(
             destruction_event, codec_width_, codec_height_))
         .set_ntp_time_ms(ntp_time_ms)
         .set_timestamp_ms(99)
         .set_rotation(kVideoRotation_0)
         .build();
   }

   VideoFrame CreateFrameWithUpdatedPixel(int64_t ntp_time_ms,
                                          rtc::Event* destruction_event,
                                          int offset_x) const {
     return VideoFrame::Builder()
         .set_video_frame_buffer(rtc::make_ref_counted<TestBuffer>(
             destruction_event, codec_width_, codec_height_))
         .set_ntp_time_ms(ntp_time_ms)
         .set_timestamp_ms(99)
         .set_rotation(kVideoRotation_0)
         .set_update_rect(VideoFrame::UpdateRect{offset_x, 0, 1, 1})
         .build();
   }

   VideoFrame CreateFrame(int64_t ntp_time_ms, int width, int height) const {
     auto buffer = rtc::make_ref_counted<TestBuffer>(nullptr, width, height);
     I420Buffer::SetBlack(buffer.get());
     return VideoFrame::Builder()
         .set_video_frame_buffer(std::move(buffer))
         .set_ntp_time_ms(ntp_time_ms)
         .set_timestamp_ms(ntp_time_ms)
         .set_rotation(kVideoRotation_0)
         .build();
   }

   VideoFrame CreateNV12Frame(int64_t ntp_time_ms, int width, int height) const {
     return VideoFrame::Builder()
         .set_video_frame_buffer(NV12Buffer::Create(width, height))
         .set_ntp_time_ms(ntp_time_ms)
         .set_timestamp_ms(ntp_time_ms)
         .set_rotation(kVideoRotation_0)
         .build();
   }

   VideoFrame CreateFakeNativeFrame(int64_t ntp_time_ms,
                                    rtc::Event* destruction_event,
                                    int width,
                                    int height) const {
     return VideoFrame::Builder()
         .set_video_frame_buffer(rtc::make_ref_counted<FakeNativeBuffer>(
             destruction_event, width, height))
         .set_ntp_time_ms(ntp_time_ms)
         .set_timestamp_ms(99)
         .set_rotation(kVideoRotation_0)
         .build();
   }

   VideoFrame CreateFakeNV12NativeFrame(int64_t ntp_time_ms,
                                        rtc::Event* destruction_event,
                                        int width,
                                        int height) const {
     return VideoFrame::Builder()
         .set_video_frame_buffer(rtc::make_ref_counted<FakeNV12NativeBuffer>(
             destruction_event, width, height))
         .set_ntp_time_ms(ntp_time_ms)
         .set_timestamp_ms(99)
         .set_rotation(kVideoRotation_0)
         .build();
   }

   VideoFrame CreateFakeNativeFrame(int64_t ntp_time_ms,
                                    rtc::Event* destruction_event) const {
     return CreateFakeNativeFrame(ntp_time_ms, destruction_event, codec_width_,
                                  codec_height_);
   }

   void VerifyAllocatedBitrate(const VideoBitrateAllocation& expected_bitrate) {
     video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
         kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);

     video_source_.IncomingCapturedFrame(
         CreateFrame(1, codec_width_, codec_height_));
     WaitForEncodedFrame(1);
     EXPECT_EQ(expected_bitrate, sink_.GetLastVideoBitrateAllocation());
   }

   void WaitForEncodedFrame(int64_t expected_ntp_time) {
     sink_.WaitForEncodedFrame(expected_ntp_time);
     AdvanceTime(TimeDelta::Seconds(1) / max_framerate_);
   }

   bool TimedWaitForEncodedFrame(int64_t expected_ntp_time, TimeDelta timeout) {
     bool ok = sink_.TimedWaitForEncodedFrame(expected_ntp_time, timeout);
     AdvanceTime(TimeDelta::Seconds(1) / max_framerate_);
     return ok;
   }

   void WaitForEncodedFrame(uint32_t expected_width, uint32_t expected_height) {
     sink_.WaitForEncodedFrame(expected_width, expected_height);
     AdvanceTime(TimeDelta::Seconds(1) / max_framerate_);
   }

   void ExpectDroppedFrame() {
     sink_.ExpectDroppedFrame();
     AdvanceTime(TimeDelta::Seconds(1) / max_framerate_);
   }

   bool WaitForFrame(TimeDelta timeout) {
     bool ok = sink_.WaitForFrame(timeout);
     AdvanceTime(TimeDelta::Seconds(1) / max_framerate_);
     return ok;
   }

   class TestEncoder : public test::FakeEncoder {
    public:
     explicit TestEncoder(TimeController* time_controller)
         : FakeEncoder(time_controller->GetClock()),
           time_controller_(time_controller) {
       RTC_DCHECK(time_controller_);
     }

     VideoEncoder::EncoderInfo GetEncoderInfo() const override {
       MutexLock lock(&local_mutex_);
       EncoderInfo info = FakeEncoder::GetEncoderInfo();
       if (initialized_ == EncoderState::kInitialized) {
         if (quality_scaling_) {
           info.scaling_settings = VideoEncoder::ScalingSettings(
               kQpLow, kQpHigh, kMinPixelsPerFrame);
         }
         info.is_hardware_accelerated = is_hardware_accelerated_;
         for (int i = 0; i < kMaxSpatialLayers; ++i) {
           if (temporal_layers_supported_[i]) {
             info.fps_allocation[i].clear();
             int num_layers = temporal_layers_supported_[i].value() ? 2 : 1;
             for (int tid = 0; tid < num_layers; ++tid)
               info.fps_allocation[i].push_back(255 / (num_layers - tid));
           }
         }
       }

       info.resolution_bitrate_limits = resolution_bitrate_limits_;
       info.requested_resolution_alignment = requested_resolution_alignment_;
       info.apply_alignment_to_all_simulcast_layers =
           apply_alignment_to_all_simulcast_layers_;
       info.preferred_pixel_formats = preferred_pixel_formats_;
       if (is_qp_trusted_.has_value()) {
         info.is_qp_trusted = is_qp_trusted_;
       }
       return info;
     }

     int32_t RegisterEncodeCompleteCallback(
         EncodedImageCallback* callback) override {
       MutexLock lock(&local_mutex_);
       encoded_image_callback_ = callback;
       return FakeEncoder::RegisterEncodeCompleteCallback(callback);
     }

     void ContinueEncode() { continue_encode_event_.Set(); }

     void CheckLastTimeStampsMatch(int64_t ntp_time_ms,
                                   uint32_t timestamp) const {
       MutexLock lock(&local_mutex_);
       EXPECT_EQ(timestamp_, timestamp);
       EXPECT_EQ(ntp_time_ms_, ntp_time_ms);
     }

     void SetQualityScaling(bool b) {
       MutexLock lock(&local_mutex_);
       quality_scaling_ = b;
     }

     void SetRequestedResolutionAlignment(
         uint32_t requested_resolution_alignment) {
       MutexLock lock(&local_mutex_);
       requested_resolution_alignment_ = requested_resolution_alignment;
     }

     void SetApplyAlignmentToAllSimulcastLayers(bool b) {
       MutexLock lock(&local_mutex_);
       apply_alignment_to_all_simulcast_layers_ = b;
     }

     void SetIsHardwareAccelerated(bool is_hardware_accelerated) {
       MutexLock lock(&local_mutex_);
       is_hardware_accelerated_ = is_hardware_accelerated;
     }

     void SetTemporalLayersSupported(size_t spatial_idx, bool supported) {
       RTC_DCHECK_LT(spatial_idx, kMaxSpatialLayers);
       MutexLock lock(&local_mutex_);
       temporal_layers_supported_[spatial_idx] = supported;
     }

     void SetResolutionBitrateLimits(
         std::vector<ResolutionBitrateLimits> thresholds) {
       MutexLock lock(&local_mutex_);
       resolution_bitrate_limits_ = thresholds;
     }

     void ForceInitEncodeFailure(bool force_failure) {
       MutexLock lock(&local_mutex_);
       force_init_encode_failed_ = force_failure;
     }

     void SimulateOvershoot(double rate_factor) {
       MutexLock lock(&local_mutex_);
       rate_factor_ = rate_factor;
     }

     uint32_t GetLastFramerate() const {
       MutexLock lock(&local_mutex_);
       return last_framerate_;
     }

     VideoFrame::UpdateRect GetLastUpdateRect() const {
       MutexLock lock(&local_mutex_);
       return last_update_rect_;
     }

     const std::vector<VideoFrameType>& LastFrameTypes() const {
       MutexLock lock(&local_mutex_);
       return last_frame_types_;
     }

     void InjectFrame(const VideoFrame& input_image, bool keyframe) {
       const std::vector<VideoFrameType> frame_type = {
           keyframe ? VideoFrameType::kVideoFrameKey
                    : VideoFrameType::kVideoFrameDelta};
       {
         MutexLock lock(&local_mutex_);
         last_frame_types_ = frame_type;
       }
       FakeEncoder::Encode(input_image, &frame_type);
     }

     void InjectEncodedImage(const EncodedImage& image,
                             const CodecSpecificInfo* codec_specific_info) {
       MutexLock lock(&local_mutex_);
       encoded_image_callback_->OnEncodedImage(image, codec_specific_info);
     }

     void SetEncodedImageData(
         rtc::scoped_refptr<EncodedImageBufferInterface> encoded_image_data) {
       MutexLock lock(&local_mutex_);
       encoded_image_data_ = encoded_image_data;
     }

     void ExpectNullFrame() {
       MutexLock lock(&local_mutex_);
       expect_null_frame_ = true;
     }

     absl::optional<VideoEncoder::RateControlParameters>
     GetAndResetLastRateControlSettings() {
       auto settings = last_rate_control_settings_;
       last_rate_control_settings_.reset();
       return settings;
     }

     int GetLastInputWidth() const {
       MutexLock lock(&local_mutex_);
       return last_input_width_;
     }

     int GetLastInputHeight() const {
       MutexLock lock(&local_mutex_);
       return last_input_height_;
     }

     absl::optional<VideoFrameBuffer::Type> GetLastInputPixelFormat() {
       MutexLock lock(&local_mutex_);
       return last_input_pixel_format_;
     }

     int GetNumSetRates() const {
       MutexLock lock(&local_mutex_);
       return num_set_rates_;
     }

     void SetPreferredPixelFormats(
         absl::InlinedVector<VideoFrameBuffer::Type, kMaxPreferredPixelFormats>
             pixel_formats) {
       MutexLock lock(&local_mutex_);
       preferred_pixel_formats_ = std::move(pixel_formats);
     }

     void SetIsQpTrusted(absl::optional<bool> trusted) {
       MutexLock lock(&local_mutex_);
       is_qp_trusted_ = trusted;
     }

     VideoCodecComplexity LastEncoderComplexity() {
       MutexLock lock(&local_mutex_);
       return last_encoder_complexity_;
     }

    private:
     int32_t Encode(const VideoFrame& input_image,
                    const std::vector<VideoFrameType>* frame_types) override {
       {
         MutexLock lock(&local_mutex_);
         if (expect_null_frame_) {
           EXPECT_EQ(input_image.timestamp(), 0u);
           EXPECT_EQ(input_image.width(), 1);
           last_frame_types_ = *frame_types;
           expect_null_frame_ = false;
         } else {
           EXPECT_GT(input_image.timestamp(), timestamp_);
           EXPECT_GT(input_image.ntp_time_ms(), ntp_time_ms_);
           EXPECT_EQ(input_image.timestamp(), input_image.ntp_time_ms() * 90);
         }

         timestamp_ = input_image.timestamp();
         ntp_time_ms_ = input_image.ntp_time_ms();
         last_input_width_ = input_image.width();
         last_input_height_ = input_image.height();
         last_update_rect_ = input_image.update_rect();
         last_frame_types_ = *frame_types;
         last_input_pixel_format_ = input_image.video_frame_buffer()->type();
       }
       int32_t result = FakeEncoder::Encode(input_image, frame_types);
       return result;
     }

     CodecSpecificInfo EncodeHook(
         EncodedImage& encoded_image,
         rtc::scoped_refptr<EncodedImageBuffer> buffer) override {
       CodecSpecificInfo codec_specific;
       {
         MutexLock lock(&mutex_);
         codec_specific.codecType = config_.codecType;
       }
       MutexLock lock(&local_mutex_);
       if (encoded_image_data_) {
         encoded_image.SetEncodedData(encoded_image_data_);
       }
       return codec_specific;
     }

     int32_t InitEncode(const VideoCodec* config,
                        const Settings& settings) override {
       int res = FakeEncoder::InitEncode(config, settings);

       MutexLock lock(&local_mutex_);
       EXPECT_EQ(initialized_, EncoderState::kUninitialized);

       if (config->codecType == kVideoCodecVP8) {
         // Simulate setting up temporal layers, in order to validate the life
         // cycle of these objects.
         Vp8TemporalLayersFactory factory;
         frame_buffer_controller_ =
             factory.Create(*config, settings, &fec_controller_override_);
       }

       last_encoder_complexity_ = config->GetVideoEncoderComplexity();

       if (force_init_encode_failed_) {
         initialized_ = EncoderState::kInitializationFailed;
         return -1;
       }

       initialized_ = EncoderState::kInitialized;
       return res;
     }

     int32_t Release() override {
       MutexLock lock(&local_mutex_);
       EXPECT_NE(initialized_, EncoderState::kUninitialized);
       initialized_ = EncoderState::kUninitialized;
       return FakeEncoder::Release();
     }

     void SetRates(const RateControlParameters& parameters) {
       MutexLock lock(&local_mutex_);
       num_set_rates_++;
       VideoBitrateAllocation adjusted_rate_allocation;
       for (size_t si = 0; si < kMaxSpatialLayers; ++si) {
         for (size_t ti = 0; ti < kMaxTemporalStreams; ++ti) {
           if (parameters.bitrate.HasBitrate(si, ti)) {
             adjusted_rate_allocation.SetBitrate(
                 si, ti,
                 static_cast<uint32_t>(parameters.bitrate.GetBitrate(si, ti) *
                                       rate_factor_));
           }
         }
       }
       last_framerate_ = static_cast<uint32_t>(parameters.framerate_fps + 0.5);
       last_rate_control_settings_ = parameters;
       RateControlParameters adjusted_paramters = parameters;
       adjusted_paramters.bitrate = adjusted_rate_allocation;
       FakeEncoder::SetRates(adjusted_paramters);
     }

     TimeController* const time_controller_;
     mutable Mutex local_mutex_;
     enum class EncoderState {
       kUninitialized,
       kInitializationFailed,
       kInitialized
     } initialized_ RTC_GUARDED_BY(local_mutex_) = EncoderState::kUninitialized;
     rtc::Event continue_encode_event_;
     uint32_t timestamp_ RTC_GUARDED_BY(local_mutex_) = 0;
     int64_t ntp_time_ms_ RTC_GUARDED_BY(local_mutex_) = 0;
     int last_input_width_ RTC_GUARDED_BY(local_mutex_) = 0;
     int last_input_height_ RTC_GUARDED_BY(local_mutex_) = 0;
     bool quality_scaling_ RTC_GUARDED_BY(local_mutex_) = true;
     uint32_t requested_resolution_alignment_ RTC_GUARDED_BY(local_mutex_) = 1;
     bool apply_alignment_to_all_simulcast_layers_ RTC_GUARDED_BY(local_mutex_) =
         false;
     bool is_hardware_accelerated_ RTC_GUARDED_BY(local_mutex_) = false;
     rtc::scoped_refptr<EncodedImageBufferInterface> encoded_image_data_
         RTC_GUARDED_BY(local_mutex_);
     std::unique_ptr<Vp8FrameBufferController> frame_buffer_controller_
         RTC_GUARDED_BY(local_mutex_);
     absl::optional<bool>
         temporal_layers_supported_[kMaxSpatialLayers] RTC_GUARDED_BY(
             local_mutex_);
     bool force_init_encode_failed_ RTC_GUARDED_BY(local_mutex_) = false;
     double rate_factor_ RTC_GUARDED_BY(local_mutex_) = 1.0;
     uint32_t last_framerate_ RTC_GUARDED_BY(local_mutex_) = 0;
     absl::optional<VideoEncoder::RateControlParameters>
         last_rate_control_settings_;
     VideoFrame::UpdateRect last_update_rect_ RTC_GUARDED_BY(local_mutex_) = {
         0, 0, 0, 0};
     std::vector<VideoFrameType> last_frame_types_;
     bool expect_null_frame_ = false;
     EncodedImageCallback* encoded_image_callback_ RTC_GUARDED_BY(local_mutex_) =
         nullptr;
     NiceMock<MockFecControllerOverride> fec_controller_override_;
     std::vector<ResolutionBitrateLimits> resolution_bitrate_limits_
         RTC_GUARDED_BY(local_mutex_);
     int num_set_rates_ RTC_GUARDED_BY(local_mutex_) = 0;
     absl::optional<VideoFrameBuffer::Type> last_input_pixel_format_
         RTC_GUARDED_BY(local_mutex_);
     absl::InlinedVector<VideoFrameBuffer::Type, kMaxPreferredPixelFormats>
         preferred_pixel_formats_ RTC_GUARDED_BY(local_mutex_);
     absl::optional<bool> is_qp_trusted_ RTC_GUARDED_BY(local_mutex_);
     VideoCodecComplexity last_encoder_complexity_ RTC_GUARDED_BY(local_mutex_){
         VideoCodecComplexity::kComplexityNormal};
   };

   class TestSink : public VideoStreamEncoder::EncoderSink {
    public:
     TestSink(TimeController* time_controller, TestEncoder* test_encoder)
         : time_controller_(time_controller), test_encoder_(test_encoder) {
       RTC_DCHECK(time_controller_);
     }

     void WaitForEncodedFrame(int64_t expected_ntp_time) {
       EXPECT_TRUE(TimedWaitForEncodedFrame(expected_ntp_time, kDefaultTimeout));
     }

     bool TimedWaitForEncodedFrame(int64_t expected_ntp_time,
                                   TimeDelta timeout) {
       uint32_t timestamp = 0;
       if (!WaitForFrame(timeout))
         return false;
       {
         MutexLock lock(&mutex_);
         timestamp = last_timestamp_;
       }
       test_encoder_->CheckLastTimeStampsMatch(expected_ntp_time, timestamp);
       return true;
     }

     void WaitForEncodedFrame(uint32_t expected_width,
                              uint32_t expected_height) {
       EXPECT_TRUE(WaitForFrame(kDefaultTimeout));
       CheckLastFrameSizeMatches(expected_width, expected_height);
     }

     void CheckLastFrameSizeMatches(uint32_t expected_width,
                                    uint32_t expected_height) {
       uint32_t width = 0;
       uint32_t height = 0;
       {
         MutexLock lock(&mutex_);
         width = last_width_;
         height = last_height_;
       }
       EXPECT_EQ(expected_height, height);
       EXPECT_EQ(expected_width, width);
     }

     void CheckLastFrameRotationMatches(VideoRotation expected_rotation) {
       VideoRotation rotation;
       {
         MutexLock lock(&mutex_);
         rotation = last_rotation_;
       }
       EXPECT_EQ(expected_rotation, rotation);
     }

     void ExpectDroppedFrame() {
       EXPECT_FALSE(WaitForFrame(TimeDelta::Millis(100)));
     }

     bool WaitForFrame(TimeDelta timeout) {
       RTC_DCHECK(time_controller_->GetMainThread()->IsCurrent());
       time_controller_->AdvanceTime(TimeDelta::Zero());
       bool ret = encoded_frame_event_.Wait(timeout);
       time_controller_->AdvanceTime(TimeDelta::Zero());
       return ret;
     }

     void SetExpectNoFrames() {
       MutexLock lock(&mutex_);
       expect_frames_ = false;
     }

     int number_of_reconfigurations() const {
       MutexLock lock(&mutex_);
       return number_of_reconfigurations_;
     }

     int last_min_transmit_bitrate() const {
       MutexLock lock(&mutex_);
       return min_transmit_bitrate_bps_;
     }

     void SetNumExpectedLayers(size_t num_layers) {
       MutexLock lock(&mutex_);
       num_expected_layers_ = num_layers;
     }

     int64_t GetLastCaptureTimeMs() const {
       MutexLock lock(&mutex_);
       return last_capture_time_ms_;
     }

     const EncodedImage& GetLastEncodedImage() {
       MutexLock lock(&mutex_);
       return last_encoded_image_;
     }

     std::vector<uint8_t> GetLastEncodedImageData() {
       MutexLock lock(&mutex_);
       return std::move(last_encoded_image_data_);
     }

     VideoBitrateAllocation GetLastVideoBitrateAllocation() {
       MutexLock lock(&mutex_);
       return last_bitrate_allocation_;
     }

     int number_of_bitrate_allocations() const {
       MutexLock lock(&mutex_);
       return number_of_bitrate_allocations_;
     }

     VideoLayersAllocation GetLastVideoLayersAllocation() {
       MutexLock lock(&mutex_);
       return last_layers_allocation_;
     }

     int number_of_layers_allocations() const {
       MutexLock lock(&mutex_);
       return number_of_layers_allocations_;
     }

    private:
     Result OnEncodedImage(
         const EncodedImage& encoded_image,
         const CodecSpecificInfo* codec_specific_info) override {
       MutexLock lock(&mutex_);
       EXPECT_TRUE(expect_frames_);
       last_encoded_image_ = EncodedImage(encoded_image);
       last_encoded_image_data_ = std::vector<uint8_t>(
           encoded_image.data(), encoded_image.data() + encoded_image.size());
       uint32_t timestamp = encoded_image.RtpTimestamp();
       if (last_timestamp_ != timestamp) {
         num_received_layers_ = 1;
         last_width_ = encoded_image._encodedWidth;
         last_height_ = encoded_image._encodedHeight;
       } else {
         ++num_received_layers_;
         last_width_ = std::max(encoded_image._encodedWidth, last_width_);
         last_height_ = std::max(encoded_image._encodedHeight, last_height_);
       }
       last_timestamp_ = timestamp;
       last_capture_time_ms_ = encoded_image.capture_time_ms_;
       last_rotation_ = encoded_image.rotation_;
       if (num_received_layers_ == num_expected_layers_) {
         encoded_frame_event_.Set();
       }
       return Result(Result::OK, last_timestamp_);
     }

     void OnEncoderConfigurationChanged(
         std::vector<VideoStream> streams,
         bool is_svc,
         VideoEncoderConfig::ContentType content_type,
         int min_transmit_bitrate_bps) override {
       MutexLock lock(&mutex_);
       ++number_of_reconfigurations_;
       min_transmit_bitrate_bps_ = min_transmit_bitrate_bps;
     }

     void OnBitrateAllocationUpdated(
         const VideoBitrateAllocation& allocation) override {
       MutexLock lock(&mutex_);
       ++number_of_bitrate_allocations_;
       last_bitrate_allocation_ = allocation;
     }

     void OnVideoLayersAllocationUpdated(
         VideoLayersAllocation allocation) override {
       MutexLock lock(&mutex_);
       ++number_of_layers_allocations_;
       last_layers_allocation_ = allocation;
       rtc::StringBuilder log;
       for (const auto& layer : allocation.active_spatial_layers) {
         log << layer.width << "x" << layer.height << "@" << layer.frame_rate_fps
             << "[";
         for (const auto target_bitrate :
              layer.target_bitrate_per_temporal_layer) {
           log << target_bitrate.kbps() << ",";
         }
         log << "]";
       }
       RTC_DLOG(LS_INFO) << "OnVideoLayersAllocationUpdated " << log.str();
     }

     TimeController* const time_controller_;
     mutable Mutex mutex_;
     TestEncoder* test_encoder_;
     rtc::Event encoded_frame_event_;
     EncodedImage last_encoded_image_;
     std::vector<uint8_t> last_encoded_image_data_;
     uint32_t last_timestamp_ = 0;
     int64_t last_capture_time_ms_ = 0;
     uint32_t last_height_ = 0;
     uint32_t last_width_ = 0;
     VideoRotation last_rotation_ = kVideoRotation_0;
     size_t num_expected_layers_ = 1;
     size_t num_received_layers_ = 0;
     bool expect_frames_ = true;
     int number_of_reconfigurations_ = 0;
     int min_transmit_bitrate_bps_ = 0;
     VideoBitrateAllocation last_bitrate_allocation_ RTC_GUARDED_BY(&mutex_);
     int number_of_bitrate_allocations_ RTC_GUARDED_BY(&mutex_) = 0;
     VideoLayersAllocation last_layers_allocation_ RTC_GUARDED_BY(&mutex_);
     int number_of_layers_allocations_ RTC_GUARDED_BY(&mutex_) = 0;
   };

   class VideoBitrateAllocatorProxyFactory
       : public VideoBitrateAllocatorFactory {
    public:
     VideoBitrateAllocatorProxyFactory()
         : bitrate_allocator_factory_(
               CreateBuiltinVideoBitrateAllocatorFactory()) {}

     std::unique_ptr<VideoBitrateAllocator> CreateVideoBitrateAllocator(
         const VideoCodec& codec) override {
       MutexLock lock(&mutex_);
       codec_config_ = codec;
       return bitrate_allocator_factory_->CreateVideoBitrateAllocator(codec);
     }

     VideoCodec codec_config() const {
       MutexLock lock(&mutex_);
       return codec_config_;
     }

    private:
     std::unique_ptr<VideoBitrateAllocatorFactory> bitrate_allocator_factory_;

     mutable Mutex mutex_;
     VideoCodec codec_config_ RTC_GUARDED_BY(mutex_);
   };

   Clock* clock() { return time_controller_.GetClock(); }
   void AdvanceTime(TimeDelta duration) {
     time_controller_.AdvanceTime(duration);
   }

   int64_t CurrentTimeMs() { return clock()->CurrentTime().ms(); }

  protected:
   virtual TaskQueueFactory* GetTaskQueueFactory() {
     return time_controller_.GetTaskQueueFactory();
   }

   test::ScopedKeyValueConfig field_trials_;
   GlobalSimulatedTimeController time_controller_{Timestamp::Micros(1234)};
   VideoSendStream::Config video_send_config_;
   VideoEncoderConfig video_encoder_config_;
   int codec_width_;
   int codec_height_;
   int max_framerate_;
   TestEncoder fake_encoder_;
   test::VideoEncoderProxyFactory encoder_factory_;
   VideoBitrateAllocatorProxyFactory bitrate_allocator_factory_;
   std::unique_ptr<MockableSendStatisticsProxy> stats_proxy_;
   TestSink sink_;
   AdaptingFrameForwarder video_source_{&time_controller_};
   std::unique_ptr<VideoStreamEncoderUnderTest> video_stream_encoder_;
 };

 TEST_F(VideoStreamEncoderTest, EncodeOneFrame) {
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);
   rtc::Event frame_destroyed_event;
   video_source_.IncomingCapturedFrame(CreateFrame(1, &frame_destroyed_event));
   WaitForEncodedFrame(1);
   EXPECT_TRUE(frame_destroyed_event.Wait(kDefaultTimeout));
   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest, DropsFramesBeforeFirstOnBitrateUpdated) {
   // Dropped since no target bitrate has been set.
   rtc::Event frame_destroyed_event;
   // The encoder will cache up to one frame for a short duration. Adding two
   // frames means that the first frame will be dropped and the second frame will
   // be sent when the encoder is enabled.
   video_source_.IncomingCapturedFrame(CreateFrame(1, &frame_destroyed_event));
   AdvanceTime(TimeDelta::Millis(10));
   video_source_.IncomingCapturedFrame(CreateFrame(2, nullptr));
   AdvanceTime(TimeDelta::Zero());
   EXPECT_TRUE(frame_destroyed_event.Wait(kDefaultTimeout));

   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);

   // The pending frame should be received.
   WaitForEncodedFrame(2);
   video_source_.IncomingCapturedFrame(CreateFrame(3, nullptr));

   WaitForEncodedFrame(3);
   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest, DropsFramesWhenRateSetToZero) {
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);
   video_source_.IncomingCapturedFrame(CreateFrame(1, nullptr));
   WaitForEncodedFrame(1);

   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       DataRate::Zero(), DataRate::Zero(), DataRate::Zero(), 0, 0, 0);

   // The encoder will cache up to one frame for a short duration. Adding two
   // frames means that the first frame will be dropped and the second frame will
   // be sent when the encoder is resumed.
   video_source_.IncomingCapturedFrame(CreateFrame(2, nullptr));
   video_source_.IncomingCapturedFrame(CreateFrame(3, nullptr));

   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);
   WaitForEncodedFrame(3);
   video_source_.IncomingCapturedFrame(CreateFrame(4, nullptr));
   WaitForEncodedFrame(4);
   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest, DropsFramesWithSameOrOldNtpTimestamp) {
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);
   video_source_.IncomingCapturedFrame(CreateFrame(1, nullptr));
   WaitForEncodedFrame(1);

   // This frame will be dropped since it has the same ntp timestamp.
   video_source_.IncomingCapturedFrame(CreateFrame(1, nullptr));

   video_source_.IncomingCapturedFrame(CreateFrame(2, nullptr));
   WaitForEncodedFrame(2);
   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest, DropsFrameAfterStop) {
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);

   video_source_.IncomingCapturedFrame(CreateFrame(1, nullptr));
   WaitForEncodedFrame(1);

   video_stream_encoder_->Stop();
   sink_.SetExpectNoFrames();
   rtc::Event frame_destroyed_event;
   video_source_.IncomingCapturedFrame(CreateFrame(2, &frame_destroyed_event));
   EXPECT_TRUE(frame_destroyed_event.Wait(kDefaultTimeout));
 }

 TEST_F(VideoStreamEncoderTest, DropsPendingFramesOnSlowEncode) {
   test::FrameForwarder source;
   video_stream_encoder_->SetSource(&source,
                                    DegradationPreference::MAINTAIN_FRAMERATE);
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);

   int dropped_count = 0;
   stats_proxy_->SetDroppedFrameCallback(
       [&dropped_count](VideoStreamEncoderObserver::DropReason) {
         ++dropped_count;
       });

   source.IncomingCapturedFrame(CreateFrame(1, nullptr));
   source.IncomingCapturedFrame(CreateFrame(2, nullptr));
   WaitForEncodedFrame(2);
   video_stream_encoder_->Stop();
   EXPECT_EQ(1, dropped_count);
 }

 TEST_F(VideoStreamEncoderTest, NativeFrameWithoutI420SupportGetsDelivered) {
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);

   rtc::Event frame_destroyed_event;
   video_source_.IncomingCapturedFrame(
       CreateFakeNativeFrame(1, &frame_destroyed_event));
   WaitForEncodedFrame(1);
   EXPECT_EQ(VideoFrameBuffer::Type::kNative,
             fake_encoder_.GetLastInputPixelFormat());
   EXPECT_EQ(fake_encoder_.config().width, fake_encoder_.GetLastInputWidth());
   EXPECT_EQ(fake_encoder_.config().height, fake_encoder_.GetLastInputHeight());
   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest,
        NativeFrameWithoutI420SupportGetsCroppedIfNecessary) {
   // Use the cropping factory.
   video_encoder_config_.video_stream_factory =
       rtc::make_ref_counted<CroppingVideoStreamFactory>();
   video_stream_encoder_->ConfigureEncoder(std::move(video_encoder_config_),
                                           kMaxPayloadLength);
   video_stream_encoder_->WaitUntilTaskQueueIsIdle();

   // Capture a frame at codec_width_/codec_height_.
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);
   video_source_.IncomingCapturedFrame(CreateFrame(1, nullptr));
   WaitForEncodedFrame(1);
   // The encoder will have been configured once.
   EXPECT_EQ(1, sink_.number_of_reconfigurations());
   EXPECT_EQ(codec_width_, fake_encoder_.config().width);
   EXPECT_EQ(codec_height_, fake_encoder_.config().height);

   // Now send in a fake frame that needs to be cropped as the width/height
   // aren't divisible by 4 (see CreateEncoderStreams above).
   rtc::Event frame_destroyed_event;
   video_source_.IncomingCapturedFrame(CreateFakeNativeFrame(
       2, &frame_destroyed_event, codec_width_ + 1, codec_height_ + 1));
   WaitForEncodedFrame(2);
   EXPECT_EQ(VideoFrameBuffer::Type::kNative,
             fake_encoder_.GetLastInputPixelFormat());
   EXPECT_EQ(fake_encoder_.config().width, fake_encoder_.GetLastInputWidth());
   EXPECT_EQ(fake_encoder_.config().height, fake_encoder_.GetLastInputHeight());
   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest, NonI420FramesShouldNotBeConvertedToI420) {
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);

   video_source_.IncomingCapturedFrame(
       CreateNV12Frame(1, codec_width_, codec_height_));
   WaitForEncodedFrame(1);
   EXPECT_EQ(VideoFrameBuffer::Type::kNV12,
             fake_encoder_.GetLastInputPixelFormat());
   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest, NativeFrameGetsDelivered_NoFrameTypePreference) {
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);

   fake_encoder_.SetPreferredPixelFormats({});

   rtc::Event frame_destroyed_event;
   video_source_.IncomingCapturedFrame(CreateFakeNV12NativeFrame(
       1, &frame_destroyed_event, codec_width_, codec_height_));
   WaitForEncodedFrame(1);
   EXPECT_EQ(VideoFrameBuffer::Type::kNative,
             fake_encoder_.GetLastInputPixelFormat());
   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest,
        NativeFrameGetsDelivered_PixelFormatPreferenceMatches) {
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);

   fake_encoder_.SetPreferredPixelFormats({VideoFrameBuffer::Type::kNV12});

   rtc::Event frame_destroyed_event;
   video_source_.IncomingCapturedFrame(CreateFakeNV12NativeFrame(
       1, &frame_destroyed_event, codec_width_, codec_height_));
   WaitForEncodedFrame(1);
   EXPECT_EQ(VideoFrameBuffer::Type::kNative,
             fake_encoder_.GetLastInputPixelFormat());
   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest, NativeFrameGetsDelivered_MappingIsNotFeasible) {
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);

   // Fake NV12 native frame does not allow mapping to I444.
   fake_encoder_.SetPreferredPixelFormats({VideoFrameBuffer::Type::kI444});

   rtc::Event frame_destroyed_event;
   video_source_.IncomingCapturedFrame(CreateFakeNV12NativeFrame(
       1, &frame_destroyed_event, codec_width_, codec_height_));
   WaitForEncodedFrame(1);
   EXPECT_EQ(VideoFrameBuffer::Type::kNative,
             fake_encoder_.GetLastInputPixelFormat());
   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest, NativeFrameGetsDelivered_BackedByNV12) {
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);

   rtc::Event frame_destroyed_event;
   video_source_.IncomingCapturedFrame(CreateFakeNV12NativeFrame(
       1, &frame_destroyed_event, codec_width_, codec_height_));
   WaitForEncodedFrame(1);
   EXPECT_EQ(VideoFrameBuffer::Type::kNative,
             fake_encoder_.GetLastInputPixelFormat());
   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest, DropsFramesWhenCongestionWindowPushbackSet) {
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);
   video_source_.IncomingCapturedFrame(CreateFrame(1, nullptr));
   WaitForEncodedFrame(1);

   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0.5);
   // The congestion window pushback is set to 0.5, which will drop 1/2 of
   // frames. Adding two frames means that the first frame will be dropped and
   // the second frame will be sent to the encoder.
   video_source_.IncomingCapturedFrame(CreateFrame(2, nullptr));
   video_source_.IncomingCapturedFrame(CreateFrame(3, nullptr));
   WaitForEncodedFrame(3);
   video_source_.IncomingCapturedFrame(CreateFrame(4, nullptr));
   video_source_.IncomingCapturedFrame(CreateFrame(5, nullptr));
   WaitForEncodedFrame(5);
   EXPECT_EQ(2u, stats_proxy_->GetStats().frames_dropped_by_congestion_window);
   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest,
        ConfigureEncoderTriggersOnEncoderConfigurationChanged) {
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);
   EXPECT_EQ(0, sink_.number_of_reconfigurations());

   // Capture a frame and wait for it to synchronize with the encoder thread.
   video_source_.IncomingCapturedFrame(CreateFrame(1, nullptr));
   WaitForEncodedFrame(1);
   // The encoder will have been configured once when the first frame is
   // received.
   EXPECT_EQ(1, sink_.number_of_reconfigurations());

   VideoEncoderConfig video_encoder_config;
   test::FillEncoderConfiguration(kVideoCodecVP8, 1, &video_encoder_config);
   video_encoder_config.min_transmit_bitrate_bps = 9999;
   video_stream_encoder_->ConfigureEncoder(std::move(video_encoder_config),
                                           kMaxPayloadLength);

   // Capture a frame and wait for it to synchronize with the encoder thread.
   video_source_.IncomingCapturedFrame(CreateFrame(2, nullptr));
   WaitForEncodedFrame(2);
   EXPECT_EQ(2, sink_.number_of_reconfigurations());
   EXPECT_EQ(9999, sink_.last_min_transmit_bitrate());

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest, FrameResolutionChangeReconfigureEncoder) {
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);

   // Capture a frame and wait for it to synchronize with the encoder thread.
   video_source_.IncomingCapturedFrame(CreateFrame(1, nullptr));
   WaitForEncodedFrame(1);
   // The encoder will have been configured once.
   EXPECT_EQ(1, sink_.number_of_reconfigurations());
   EXPECT_EQ(codec_width_, fake_encoder_.config().width);
   EXPECT_EQ(codec_height_, fake_encoder_.config().height);

   codec_width_ *= 2;
   codec_height_ *= 2;
   // Capture a frame with a higher resolution and wait for it to synchronize
   // with the encoder thread.
   video_source_.IncomingCapturedFrame(CreateFrame(2, nullptr));
   WaitForEncodedFrame(2);
   EXPECT_EQ(codec_width_, fake_encoder_.config().width);
   EXPECT_EQ(codec_height_, fake_encoder_.config().height);
   EXPECT_EQ(2, sink_.number_of_reconfigurations());

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest,
        EncoderInstanceDestroyedBeforeAnotherInstanceCreated) {
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);

   // Capture a frame and wait for it to synchronize with the encoder thread.
   video_source_.IncomingCapturedFrame(CreateFrame(1, nullptr));
   WaitForEncodedFrame(1);

   VideoEncoderConfig video_encoder_config;
   test::FillEncoderConfiguration(kVideoCodecVP8, 1, &video_encoder_config);
   // Changing the max payload data length recreates encoder.
   video_stream_encoder_->ConfigureEncoder(std::move(video_encoder_config),
                                           kMaxPayloadLength / 2);

   // Capture a frame and wait for it to synchronize with the encoder thread.
   video_source_.IncomingCapturedFrame(CreateFrame(2, nullptr));
   WaitForEncodedFrame(2);
   EXPECT_EQ(1, encoder_factory_.GetMaxNumberOfSimultaneousEncoderInstances());

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest, BitrateLimitsChangeReconfigureRateAllocator) {
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);

   VideoEncoderConfig video_encoder_config;
   test::FillEncoderConfiguration(kVideoCodecVP8, 1, &video_encoder_config);
   video_encoder_config.max_bitrate_bps = kTargetBitrate.bps();
   video_stream_encoder_->SetStartBitrate(kStartBitrate.bps());
   video_stream_encoder_->ConfigureEncoder(video_encoder_config.Copy(),
                                           kMaxPayloadLength);

   // Capture a frame and wait for it to synchronize with the encoder thread.
   video_source_.IncomingCapturedFrame(CreateFrame(1, nullptr));
   WaitForEncodedFrame(1);
   // The encoder will have been configured once when the first frame is
   // received.
   EXPECT_EQ(1, sink_.number_of_reconfigurations());
   EXPECT_EQ(kTargetBitrate.bps(),
             bitrate_allocator_factory_.codec_config().maxBitrate * 1000);
   EXPECT_EQ(kStartBitrate.bps(),
             bitrate_allocator_factory_.codec_config().startBitrate * 1000);

   test::FillEncoderConfiguration(kVideoCodecVP8, 1,
                                  &video_encoder_config);  //???
   video_encoder_config.max_bitrate_bps = kTargetBitrate.bps() * 2;
   video_stream_encoder_->SetStartBitrate(kStartBitrate.bps() * 2);
   video_stream_encoder_->ConfigureEncoder(std::move(video_encoder_config),
                                           kMaxPayloadLength);

   // Capture a frame and wait for it to synchronize with the encoder thread.
   video_source_.IncomingCapturedFrame(CreateFrame(2, nullptr));
   WaitForEncodedFrame(2);
   EXPECT_EQ(2, sink_.number_of_reconfigurations());
   // Bitrate limits have changed - rate allocator should be reconfigured,
   // encoder should not be reconfigured.
   EXPECT_EQ(kTargetBitrate.bps() * 2,
             bitrate_allocator_factory_.codec_config().maxBitrate * 1000);
   EXPECT_EQ(kStartBitrate.bps() * 2,
             bitrate_allocator_factory_.codec_config().startBitrate * 1000);
   EXPECT_EQ(1, fake_encoder_.GetNumInitializations());

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest,
        IntersectionOfEncoderAndAppBitrateLimitsUsedWhenBothProvided) {
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);

   const uint32_t kMinEncBitrateKbps = 100;
   const uint32_t kMaxEncBitrateKbps = 1000;
   const VideoEncoder::ResolutionBitrateLimits encoder_bitrate_limits(
       /*frame_size_pixels=*/codec_width_ * codec_height_,
       /*min_start_bitrate_bps=*/0,
       /*min_bitrate_bps=*/kMinEncBitrateKbps * 1000,
       /*max_bitrate_bps=*/kMaxEncBitrateKbps * 1000);
   fake_encoder_.SetResolutionBitrateLimits({encoder_bitrate_limits});

   VideoEncoderConfig video_encoder_config;
   test::FillEncoderConfiguration(kVideoCodecVP8, 1, &video_encoder_config);
   video_encoder_config.max_bitrate_bps = (kMaxEncBitrateKbps + 1) * 1000;
   video_encoder_config.simulcast_layers[0].min_bitrate_bps =
       (kMinEncBitrateKbps + 1) * 1000;
   video_stream_encoder_->ConfigureEncoder(video_encoder_config.Copy(),
                                           kMaxPayloadLength);

   // When both encoder and app provide bitrate limits, the intersection of
   // provided sets should be used.
   video_source_.IncomingCapturedFrame(CreateFrame(1, nullptr));
   WaitForEncodedFrame(1);
   EXPECT_EQ(kMaxEncBitrateKbps,
             bitrate_allocator_factory_.codec_config().maxBitrate);
   EXPECT_EQ(kMinEncBitrateKbps + 1,
             bitrate_allocator_factory_.codec_config().minBitrate);

   video_encoder_config.max_bitrate_bps = (kMaxEncBitrateKbps - 1) * 1000;
   video_encoder_config.simulcast_layers[0].min_bitrate_bps =
       (kMinEncBitrateKbps - 1) * 1000;
   video_stream_encoder_->ConfigureEncoder(video_encoder_config.Copy(),
                                           kMaxPayloadLength);
   video_source_.IncomingCapturedFrame(CreateFrame(2, nullptr));
   WaitForEncodedFrame(2);
   EXPECT_EQ(kMaxEncBitrateKbps - 1,
             bitrate_allocator_factory_.codec_config().maxBitrate);
   EXPECT_EQ(kMinEncBitrateKbps,
             bitrate_allocator_factory_.codec_config().minBitrate);

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest,
        EncoderAndAppLimitsDontIntersectEncoderLimitsIgnored) {
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);

   const uint32_t kMinAppBitrateKbps = 100;
   const uint32_t kMaxAppBitrateKbps = 200;
   const uint32_t kMinEncBitrateKbps = kMaxAppBitrateKbps + 1;
   const uint32_t kMaxEncBitrateKbps = kMaxAppBitrateKbps * 2;
   const VideoEncoder::ResolutionBitrateLimits encoder_bitrate_limits(
       /*frame_size_pixels=*/codec_width_ * codec_height_,
       /*min_start_bitrate_bps=*/0,
       /*min_bitrate_bps=*/kMinEncBitrateKbps * 1000,
       /*max_bitrate_bps=*/kMaxEncBitrateKbps * 1000);
   fake_encoder_.SetResolutionBitrateLimits({encoder_bitrate_limits});

   VideoEncoderConfig video_encoder_config;
   test::FillEncoderConfiguration(kVideoCodecVP8, 1, &video_encoder_config);
   video_encoder_config.max_bitrate_bps = kMaxAppBitrateKbps * 1000;
   video_encoder_config.simulcast_layers[0].min_bitrate_bps =
       kMinAppBitrateKbps * 1000;
   video_stream_encoder_->ConfigureEncoder(video_encoder_config.Copy(),
                                           kMaxPayloadLength);

   video_source_.IncomingCapturedFrame(CreateFrame(1, nullptr));
   WaitForEncodedFrame(1);
   EXPECT_EQ(kMaxAppBitrateKbps,
             bitrate_allocator_factory_.codec_config().maxBitrate);
   EXPECT_EQ(kMinAppBitrateKbps,
             bitrate_allocator_factory_.codec_config().minBitrate);

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest,
        EncoderRecommendedMaxAndMinBitratesUsedForGivenResolution) {
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);

   const VideoEncoder::ResolutionBitrateLimits encoder_bitrate_limits_270p(
       480 * 270, 34 * 1000, 12 * 1000, 1234 * 1000);
   const VideoEncoder::ResolutionBitrateLimits encoder_bitrate_limits_360p(
       640 * 360, 43 * 1000, 21 * 1000, 2345 * 1000);
   fake_encoder_.SetResolutionBitrateLimits(
       {encoder_bitrate_limits_270p, encoder_bitrate_limits_360p});

   VideoEncoderConfig video_encoder_config;
   test::FillEncoderConfiguration(kVideoCodecVP8, 1, &video_encoder_config);
   video_encoder_config.max_bitrate_bps = 0;
   video_stream_encoder_->ConfigureEncoder(video_encoder_config.Copy(),
                                           kMaxPayloadLength);

   // 270p. The bitrate limits recommended by encoder for 270p should be used.
   video_source_.IncomingCapturedFrame(CreateFrame(1, 480, 270));
   WaitForEncodedFrame(1);
   EXPECT_EQ(static_cast<uint32_t>(encoder_bitrate_limits_270p.min_bitrate_bps),
             bitrate_allocator_factory_.codec_config().minBitrate * 1000);
   EXPECT_EQ(static_cast<uint32_t>(encoder_bitrate_limits_270p.max_bitrate_bps),
             bitrate_allocator_factory_.codec_config().maxBitrate * 1000);

   // 360p. The bitrate limits recommended by encoder for 360p should be used.
   video_source_.IncomingCapturedFrame(CreateFrame(2, 640, 360));
   WaitForEncodedFrame(2);
   EXPECT_EQ(static_cast<uint32_t>(encoder_bitrate_limits_360p.min_bitrate_bps),
             bitrate_allocator_factory_.codec_config().minBitrate * 1000);
   EXPECT_EQ(static_cast<uint32_t>(encoder_bitrate_limits_360p.max_bitrate_bps),
             bitrate_allocator_factory_.codec_config().maxBitrate * 1000);

   // Resolution between 270p and 360p. The bitrate limits recommended by
   // encoder for 360p should be used.
   video_source_.IncomingCapturedFrame(
       CreateFrame(3, (640 + 480) / 2, (360 + 270) / 2));
   WaitForEncodedFrame(3);
   EXPECT_EQ(static_cast<uint32_t>(encoder_bitrate_limits_360p.min_bitrate_bps),
             bitrate_allocator_factory_.codec_config().minBitrate * 1000);
   EXPECT_EQ(static_cast<uint32_t>(encoder_bitrate_limits_360p.max_bitrate_bps),
             bitrate_allocator_factory_.codec_config().maxBitrate * 1000);

   // Resolution higher than 360p. The caps recommended by encoder should be
   // ignored.
   video_source_.IncomingCapturedFrame(CreateFrame(4, 960, 540));
   WaitForEncodedFrame(4);
   EXPECT_NE(static_cast<uint32_t>(encoder_bitrate_limits_270p.min_bitrate_bps),
             bitrate_allocator_factory_.codec_config().minBitrate * 1000);
   EXPECT_NE(static_cast<uint32_t>(encoder_bitrate_limits_270p.max_bitrate_bps),
             bitrate_allocator_factory_.codec_config().maxBitrate * 1000);
   EXPECT_NE(static_cast<uint32_t>(encoder_bitrate_limits_360p.min_bitrate_bps),
             bitrate_allocator_factory_.codec_config().minBitrate * 1000);
   EXPECT_NE(static_cast<uint32_t>(encoder_bitrate_limits_360p.max_bitrate_bps),
             bitrate_allocator_factory_.codec_config().maxBitrate * 1000);

   // Resolution lower than 270p. The max bitrate limit recommended by encoder
   // for 270p should be used.
   video_source_.IncomingCapturedFrame(CreateFrame(5, 320, 180));
   WaitForEncodedFrame(5);
   EXPECT_EQ(static_cast<uint32_t>(encoder_bitrate_limits_270p.min_bitrate_bps),
             bitrate_allocator_factory_.codec_config().minBitrate * 1000);
   EXPECT_EQ(static_cast<uint32_t>(encoder_bitrate_limits_270p.max_bitrate_bps),
             bitrate_allocator_factory_.codec_config().maxBitrate * 1000);

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest, EncoderRecommendedMaxBitrateCapsTargetBitrate) {
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);

   VideoEncoderConfig video_encoder_config;
   test::FillEncoderConfiguration(kVideoCodecVP8, 1, &video_encoder_config);
   video_encoder_config.max_bitrate_bps = 0;
   video_stream_encoder_->ConfigureEncoder(video_encoder_config.Copy(),
                                           kMaxPayloadLength);

   // Encode 720p frame to get the default encoder target bitrate.
   video_source_.IncomingCapturedFrame(CreateFrame(1, 1280, 720));
   WaitForEncodedFrame(1);
   const uint32_t kDefaultTargetBitrateFor720pKbps =
       bitrate_allocator_factory_.codec_config()
           .simulcastStream[0]
           .targetBitrate;

   // Set the max recommended encoder bitrate to something lower than the default
   // target bitrate.
   const VideoEncoder::ResolutionBitrateLimits encoder_bitrate_limits(
       1280 * 720, 10 * 1000, 10 * 1000,
       kDefaultTargetBitrateFor720pKbps / 2 * 1000);
   fake_encoder_.SetResolutionBitrateLimits({encoder_bitrate_limits});

   // Change resolution to trigger encoder reinitialization.
   video_source_.IncomingCapturedFrame(CreateFrame(2, 640, 360));
   WaitForEncodedFrame(2);
   video_source_.IncomingCapturedFrame(CreateFrame(3, 1280, 720));
   WaitForEncodedFrame(3);

   // Ensure the target bitrate is capped by the max bitrate.
   EXPECT_EQ(bitrate_allocator_factory_.codec_config().maxBitrate * 1000,
             static_cast<uint32_t>(encoder_bitrate_limits.max_bitrate_bps));
   EXPECT_EQ(bitrate_allocator_factory_.codec_config()
                     .simulcastStream[0]
                     .targetBitrate *
                 1000,
             static_cast<uint32_t>(encoder_bitrate_limits.max_bitrate_bps));

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest,
        EncoderMaxAndMinBitratesUsedForTwoStreamsHighestActive) {
   const VideoEncoder::ResolutionBitrateLimits kEncoderLimits270p(
       480 * 270, 34 * 1000, 12 * 1000, 1234 * 1000);
   const VideoEncoder::ResolutionBitrateLimits kEncoderLimits360p(
       640 * 360, 43 * 1000, 21 * 1000, 2345 * 1000);
   fake_encoder_.SetResolutionBitrateLimits(
       {kEncoderLimits270p, kEncoderLimits360p});

   // Two streams, highest stream active.
   VideoEncoderConfig config;
   webrtc::VideoEncoder::EncoderInfo encoder_info;
   const int kNumStreams = 2;
   test::FillEncoderConfiguration(kVideoCodecVP8, kNumStreams, &config);
   config.max_bitrate_bps = 0;
   config.simulcast_layers[0].active = false;
   config.simulcast_layers[1].active = true;
   config.video_stream_factory =
       rtc::make_ref_counted<cricket::EncoderStreamFactory>(
           "VP8", /*max qp*/ 56, /*screencast*/ false,
           /*screenshare enabled*/ false, encoder_info);
   video_stream_encoder_->ConfigureEncoder(config.Copy(), kMaxPayloadLength);

   // The encoder bitrate limits for 270p should be used.
   video_source_.IncomingCapturedFrame(CreateFrame(1, 480, 270));
   video_stream_encoder_->WaitUntilTaskQueueIsIdle();
   EXPECT_EQ(fake_encoder_.config().numberOfSimulcastStreams, kNumStreams);
   EXPECT_EQ(static_cast<uint32_t>(kEncoderLimits270p.min_bitrate_bps),
             fake_encoder_.config().simulcastStream[1].minBitrate * 1000);
   EXPECT_EQ(static_cast<uint32_t>(kEncoderLimits270p.max_bitrate_bps),
             fake_encoder_.config().simulcastStream[1].maxBitrate * 1000);

   // The encoder bitrate limits for 360p should be used.
   video_source_.IncomingCapturedFrame(CreateFrame(2, 640, 360));
   video_stream_encoder_->WaitUntilTaskQueueIsIdle();
   EXPECT_EQ(static_cast<uint32_t>(kEncoderLimits360p.min_bitrate_bps),
             fake_encoder_.config().simulcastStream[1].minBitrate * 1000);
   EXPECT_EQ(static_cast<uint32_t>(kEncoderLimits360p.max_bitrate_bps),
             fake_encoder_.config().simulcastStream[1].maxBitrate * 1000);

   // Resolution b/w 270p and 360p. The encoder limits for 360p should be used.
   video_source_.IncomingCapturedFrame(
       CreateFrame(3, (640 + 480) / 2, (360 + 270) / 2));
   video_stream_encoder_->WaitUntilTaskQueueIsIdle();
   EXPECT_EQ(static_cast<uint32_t>(kEncoderLimits360p.min_bitrate_bps),
             fake_encoder_.config().simulcastStream[1].minBitrate * 1000);
   EXPECT_EQ(static_cast<uint32_t>(kEncoderLimits360p.max_bitrate_bps),
             fake_encoder_.config().simulcastStream[1].maxBitrate * 1000);

   // Resolution higher than 360p. Encoder limits should be ignored.
   video_source_.IncomingCapturedFrame(CreateFrame(4, 960, 540));
   video_stream_encoder_->WaitUntilTaskQueueIsIdle();
   EXPECT_NE(static_cast<uint32_t>(kEncoderLimits270p.min_bitrate_bps),
             fake_encoder_.config().simulcastStream[1].minBitrate * 1000);
   EXPECT_NE(static_cast<uint32_t>(kEncoderLimits270p.max_bitrate_bps),
             fake_encoder_.config().simulcastStream[1].maxBitrate * 1000);
   EXPECT_NE(static_cast<uint32_t>(kEncoderLimits360p.min_bitrate_bps),
             fake_encoder_.config().simulcastStream[1].minBitrate * 1000);
   EXPECT_NE(static_cast<uint32_t>(kEncoderLimits360p.max_bitrate_bps),
             fake_encoder_.config().simulcastStream[1].maxBitrate * 1000);

   // Resolution lower than 270p. The encoder limits for 270p should be used.
   video_source_.IncomingCapturedFrame(CreateFrame(5, 320, 180));
   video_stream_encoder_->WaitUntilTaskQueueIsIdle();
   EXPECT_EQ(static_cast<uint32_t>(kEncoderLimits270p.min_bitrate_bps),
             fake_encoder_.config().simulcastStream[1].minBitrate * 1000);
   EXPECT_EQ(static_cast<uint32_t>(kEncoderLimits270p.max_bitrate_bps),
             fake_encoder_.config().simulcastStream[1].maxBitrate * 1000);

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest,
        DefaultEncoderMaxAndMinBitratesUsedForTwoStreamsHighestActive) {
   // Two streams, highest stream active.
   VideoEncoderConfig config;
   webrtc::VideoEncoder::EncoderInfo encoder_info;
   const int kNumStreams = 2;
   test::FillEncoderConfiguration(kVideoCodecVP8, kNumStreams, &config);
   config.max_bitrate_bps = 0;
   config.simulcast_layers[0].active = false;
   config.simulcast_layers[1].active = true;
   config.video_stream_factory =
       rtc::make_ref_counted<cricket::EncoderStreamFactory>(
           "VP8", /*max qp*/ 56, /*screencast*/ false,
           /*screenshare enabled*/ false, encoder_info);
   video_stream_encoder_->ConfigureEncoder(config.Copy(), kMaxPayloadLength);

   // Default bitrate limits for 270p should be used.
   const absl::optional<VideoEncoder::ResolutionBitrateLimits>
       kDefaultLimits270p =
           EncoderInfoSettings::GetDefaultSinglecastBitrateLimitsForResolution(
               kVideoCodecVP8, 480 * 270);
   video_source_.IncomingCapturedFrame(CreateFrame(1, 480, 270));
   video_stream_encoder_->WaitUntilTaskQueueIsIdle();
   EXPECT_EQ(fake_encoder_.config().numberOfSimulcastStreams, kNumStreams);
   EXPECT_EQ(static_cast<uint32_t>(kDefaultLimits270p->min_bitrate_bps),
             fake_encoder_.config().simulcastStream[1].minBitrate * 1000);
   EXPECT_EQ(static_cast<uint32_t>(kDefaultLimits270p->max_bitrate_bps),
             fake_encoder_.config().simulcastStream[1].maxBitrate * 1000);

   // Default bitrate limits for 360p should be used.
   const absl::optional<VideoEncoder::ResolutionBitrateLimits>
       kDefaultLimits360p =
           EncoderInfoSettings::GetDefaultSinglecastBitrateLimitsForResolution(
               kVideoCodecVP8, 640 * 360);
   video_source_.IncomingCapturedFrame(CreateFrame(2, 640, 360));
   video_stream_encoder_->WaitUntilTaskQueueIsIdle();
   EXPECT_EQ(static_cast<uint32_t>(kDefaultLimits360p->min_bitrate_bps),
             fake_encoder_.config().simulcastStream[1].minBitrate * 1000);
   EXPECT_EQ(static_cast<uint32_t>(kDefaultLimits360p->max_bitrate_bps),
             fake_encoder_.config().simulcastStream[1].maxBitrate * 1000);

   // Resolution b/w 270p and 360p. The default limits for 360p should be used.
   video_source_.IncomingCapturedFrame(
       CreateFrame(3, (640 + 480) / 2, (360 + 270) / 2));
   video_stream_encoder_->WaitUntilTaskQueueIsIdle();
   EXPECT_EQ(static_cast<uint32_t>(kDefaultLimits360p->min_bitrate_bps),
             fake_encoder_.config().simulcastStream[1].minBitrate * 1000);
   EXPECT_EQ(static_cast<uint32_t>(kDefaultLimits360p->max_bitrate_bps),
             fake_encoder_.config().simulcastStream[1].maxBitrate * 1000);

   // Default bitrate limits for 540p should be used.
   const absl::optional<VideoEncoder::ResolutionBitrateLimits>
       kDefaultLimits540p =
           EncoderInfoSettings::GetDefaultSinglecastBitrateLimitsForResolution(
               kVideoCodecVP8, 960 * 540);
   video_source_.IncomingCapturedFrame(CreateFrame(4, 960, 540));
   video_stream_encoder_->WaitUntilTaskQueueIsIdle();
   EXPECT_EQ(static_cast<uint32_t>(kDefaultLimits540p->min_bitrate_bps),
             fake_encoder_.config().simulcastStream[1].minBitrate * 1000);
   EXPECT_EQ(static_cast<uint32_t>(kDefaultLimits540p->max_bitrate_bps),
             fake_encoder_.config().simulcastStream[1].maxBitrate * 1000);

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest,
        EncoderMaxAndMinBitratesUsedForThreeStreamsMiddleActive) {
   const VideoEncoder::ResolutionBitrateLimits kEncoderLimits270p(
       480 * 270, 34 * 1000, 12 * 1000, 1234 * 1000);
   const VideoEncoder::ResolutionBitrateLimits kEncoderLimits360p(
       640 * 360, 43 * 1000, 21 * 1000, 2345 * 1000);
   const VideoEncoder::ResolutionBitrateLimits kEncoderLimits720p(
       1280 * 720, 54 * 1000, 31 * 1000, 3456 * 1000);
   fake_encoder_.SetResolutionBitrateLimits(
       {kEncoderLimits270p, kEncoderLimits360p, kEncoderLimits720p});

   // Three streams, middle stream active.
   VideoEncoderConfig config;
   webrtc::VideoEncoder::EncoderInfo encoder_info;
   const int kNumStreams = 3;
   test::FillEncoderConfiguration(kVideoCodecVP8, kNumStreams, &config);
   config.simulcast_layers[0].active = false;
   config.simulcast_layers[1].active = true;
   config.simulcast_layers[2].active = false;
   config.video_stream_factory =
       rtc::make_ref_counted<cricket::EncoderStreamFactory>(
           "VP8", /*max qp*/ 56, /*screencast*/ false,
           /*screenshare enabled*/ false, encoder_info);
   video_stream_encoder_->ConfigureEncoder(config.Copy(), kMaxPayloadLength);

   // The encoder bitrate limits for 360p should be used.
   video_source_.IncomingCapturedFrame(CreateFrame(1, 1280, 720));
   video_stream_encoder_->WaitUntilTaskQueueIsIdle();
   EXPECT_EQ(fake_encoder_.config().numberOfSimulcastStreams, kNumStreams);
   EXPECT_EQ(static_cast<uint32_t>(kEncoderLimits360p.min_bitrate_bps),
             fake_encoder_.config().simulcastStream[1].minBitrate * 1000);
   EXPECT_EQ(static_cast<uint32_t>(kEncoderLimits360p.max_bitrate_bps),
             fake_encoder_.config().simulcastStream[1].maxBitrate * 1000);

   // The encoder bitrate limits for 270p should be used.
   video_source_.IncomingCapturedFrame(CreateFrame(2, 960, 540));
   video_stream_encoder_->WaitUntilTaskQueueIsIdle();
   EXPECT_EQ(static_cast<uint32_t>(kEncoderLimits270p.min_bitrate_bps),
             fake_encoder_.config().simulcastStream[1].minBitrate * 1000);
   EXPECT_EQ(static_cast<uint32_t>(kEncoderLimits270p.max_bitrate_bps),
             fake_encoder_.config().simulcastStream[1].maxBitrate * 1000);

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest,
        EncoderMaxAndMinBitratesNotUsedForThreeStreamsLowestActive) {
   const VideoEncoder::ResolutionBitrateLimits kEncoderLimits270p(
       480 * 270, 34 * 1000, 12 * 1000, 1234 * 1000);
   const VideoEncoder::ResolutionBitrateLimits kEncoderLimits360p(
       640 * 360, 43 * 1000, 21 * 1000, 2345 * 1000);
   const VideoEncoder::ResolutionBitrateLimits kEncoderLimits720p(
       1280 * 720, 54 * 1000, 31 * 1000, 3456 * 1000);
   fake_encoder_.SetResolutionBitrateLimits(
       {kEncoderLimits270p, kEncoderLimits360p, kEncoderLimits720p});

   // Three streams, lowest stream active.
   VideoEncoderConfig config;
   webrtc::VideoEncoder::EncoderInfo encoder_info;
   const int kNumStreams = 3;
   test::FillEncoderConfiguration(kVideoCodecVP8, kNumStreams, &config);
   config.simulcast_layers[0].active = true;
   config.simulcast_layers[1].active = false;
   config.simulcast_layers[2].active = false;
   config.video_stream_factory =
       rtc::make_ref_counted<cricket::EncoderStreamFactory>(
           "VP8", /*max qp*/ 56, /*screencast*/ false,
           /*screenshare enabled*/ false, encoder_info);
   video_stream_encoder_->ConfigureEncoder(config.Copy(), kMaxPayloadLength);

   // Resolution on lowest stream lower than 270p. The encoder limits not applied
   // on lowest stream, limits for 270p should not be used
   video_source_.IncomingCapturedFrame(CreateFrame(1, 1280, 720));
   video_stream_encoder_->WaitUntilTaskQueueIsIdle();
   EXPECT_EQ(fake_encoder_.config().numberOfSimulcastStreams, kNumStreams);
   EXPECT_NE(static_cast<uint32_t>(kEncoderLimits270p.min_bitrate_bps),
             fake_encoder_.config().simulcastStream[1].minBitrate * 1000);
   EXPECT_NE(static_cast<uint32_t>(kEncoderLimits270p.max_bitrate_bps),
             fake_encoder_.config().simulcastStream[1].maxBitrate * 1000);

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest,
        EncoderMaxBitrateCappedByConfigForTwoStreamsHighestActive) {
   const VideoEncoder::ResolutionBitrateLimits kEncoderLimits270p(
       480 * 270, 34 * 1000, 12 * 1000, 1234 * 1000);
   const VideoEncoder::ResolutionBitrateLimits kEncoderLimits360p(
       640 * 360, 43 * 1000, 21 * 1000, 2345 * 1000);
   fake_encoder_.SetResolutionBitrateLimits(
       {kEncoderLimits270p, kEncoderLimits360p});
   const int kMaxBitrateBps = kEncoderLimits360p.max_bitrate_bps - 100 * 1000;

   // Two streams, highest stream active.
   VideoEncoderConfig config;
   webrtc::VideoEncoder::EncoderInfo encoder_info;
   const int kNumStreams = 2;
   test::FillEncoderConfiguration(kVideoCodecVP8, kNumStreams, &config);
   config.simulcast_layers[0].active = false;
   config.simulcast_layers[1].active = true;
   config.simulcast_layers[1].max_bitrate_bps = kMaxBitrateBps;
   config.video_stream_factory =
       rtc::make_ref_counted<cricket::EncoderStreamFactory>(
           "VP8", /*max qp*/ 56, /*screencast*/ false,
           /*screenshare enabled*/ false, encoder_info);
   video_stream_encoder_->ConfigureEncoder(config.Copy(), kMaxPayloadLength);

   // The encoder bitrate limits for 270p should be used.
   video_source_.IncomingCapturedFrame(CreateFrame(1, 480, 270));
   video_stream_encoder_->WaitUntilTaskQueueIsIdle();
   EXPECT_EQ(fake_encoder_.config().numberOfSimulcastStreams, kNumStreams);
   EXPECT_EQ(static_cast<uint32_t>(kEncoderLimits270p.min_bitrate_bps),
             fake_encoder_.config().simulcastStream[1].minBitrate * 1000);
   EXPECT_EQ(static_cast<uint32_t>(kEncoderLimits270p.max_bitrate_bps),
             fake_encoder_.config().simulcastStream[1].maxBitrate * 1000);

   // The max configured bitrate is less than the encoder limit for 360p.
   video_source_.IncomingCapturedFrame(CreateFrame(2, 640, 360));
   video_stream_encoder_->WaitUntilTaskQueueIsIdle();
   EXPECT_EQ(static_cast<uint32_t>(kEncoderLimits360p.min_bitrate_bps),
             fake_encoder_.config().simulcastStream[1].minBitrate * 1000);
   EXPECT_EQ(static_cast<uint32_t>(kMaxBitrateBps),
             fake_encoder_.config().simulcastStream[1].maxBitrate * 1000);

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest, SwitchSourceDeregisterEncoderAsSink) {
   EXPECT_TRUE(video_source_.has_sinks());
   test::FrameForwarder new_video_source;
   video_stream_encoder_->SetSource(
       &new_video_source, webrtc::DegradationPreference::MAINTAIN_FRAMERATE);
   EXPECT_FALSE(video_source_.has_sinks());
   EXPECT_TRUE(new_video_source.has_sinks());

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest, SinkWantsRotationApplied) {
   EXPECT_FALSE(video_source_.sink_wants().rotation_applied);
   video_stream_encoder_->SetSink(&sink_, true /*rotation_applied*/);
   EXPECT_TRUE(video_source_.sink_wants().rotation_applied);
   video_stream_encoder_->Stop();
 }

 class ResolutionAlignmentTest
     : public VideoStreamEncoderTest,
       public ::testing::WithParamInterface<
           ::testing::tuple<int, std::vector<double>>> {
  public:
   ResolutionAlignmentTest()
       : requested_alignment_(::testing::get<0>(GetParam())),
         scale_factors_(::testing::get<1>(GetParam())) {}

  protected:
   const uint32_t requested_alignment_;
   const std::vector<double> scale_factors_;
 };

 INSTANTIATE_TEST_SUITE_P(
     AlignmentAndScaleFactors,
     ResolutionAlignmentTest,
     ::testing::Combine(
         ::testing::Values(1, 2, 3, 4, 5, 6, 16, 22),  // requested_alignment_
         ::testing::Values(std::vector<double>{-1.0},  // scale_factors_
                           std::vector<double>{-1.0, -1.0},
                           std::vector<double>{-1.0, -1.0, -1.0},
                           std::vector<double>{4.0, 2.0, 1.0},
                           std::vector<double>{9999.0, -1.0, 1.0},
                           std::vector<double>{3.99, 2.01, 1.0},
                           std::vector<double>{4.9, 1.7, 1.25},
                           std::vector<double>{10.0, 4.0, 3.0},
                           std::vector<double>{1.75, 3.5},
                           std::vector<double>{1.5, 2.5},
                           std::vector<double>{1.3, 1.0})));

 TEST_P(ResolutionAlignmentTest, SinkWantsAlignmentApplied) {
   // Set requested resolution alignment.
   video_source_.set_adaptation_enabled(true);
   fake_encoder_.SetRequestedResolutionAlignment(requested_alignment_);
   fake_encoder_.SetApplyAlignmentToAllSimulcastLayers(true);

   // Fill config with the scaling factor by which to reduce encoding size.
   const int num_streams = scale_factors_.size();
   VideoEncoderConfig config;
   webrtc::VideoEncoder::EncoderInfo encoder_info;
   test::FillEncoderConfiguration(kVideoCodecVP8, num_streams, &config);
   for (int i = 0; i < num_streams; ++i) {
     config.simulcast_layers[i].scale_resolution_down_by = scale_factors_[i];
   }
   config.video_stream_factory =
       rtc::make_ref_counted<cricket::EncoderStreamFactory>(
           "VP8", /*max qp*/ 56, /*screencast*/ false,
           /*screenshare enabled*/ false, encoder_info);
   video_stream_encoder_->ConfigureEncoder(std::move(config), kMaxPayloadLength);

   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kSimulcastTargetBitrate, kSimulcastTargetBitrate, kSimulcastTargetBitrate,
       0, 0, 0);
   // Wait for all layers before triggering event.
   sink_.SetNumExpectedLayers(num_streams);

   // On the 1st frame, we should have initialized the encoder and
   // asked for its resolution requirements.
   int64_t timestamp_ms = kFrameIntervalMs;
   video_source_.IncomingCapturedFrame(CreateFrame(timestamp_ms, 1280, 720));
   WaitForEncodedFrame(timestamp_ms);
   EXPECT_EQ(1, fake_encoder_.GetNumInitializations());

   // On the 2nd frame, we should be receiving a correctly aligned resolution.
   // (It's up the to the encoder to potentially drop the previous frame,
   // to avoid coding back-to-back keyframes.)
   timestamp_ms += kFrameIntervalMs;
   video_source_.IncomingCapturedFrame(CreateFrame(timestamp_ms, 1280, 720));
   WaitForEncodedFrame(timestamp_ms);
   EXPECT_GE(fake_encoder_.GetNumInitializations(), 1);

   VideoCodec codec = fake_encoder_.config();
   EXPECT_EQ(codec.numberOfSimulcastStreams, num_streams);
   // Frame size should be a multiple of the requested alignment.
   for (int i = 0; i < codec.numberOfSimulcastStreams; ++i) {
     EXPECT_EQ(codec.simulcastStream[i].width % requested_alignment_, 0u);
     EXPECT_EQ(codec.simulcastStream[i].height % requested_alignment_, 0u);
     // Aspect ratio should match.
     EXPECT_EQ(codec.width * codec.simulcastStream[i].height,
               codec.height * codec.simulcastStream[i].width);
   }

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest, TestCpuDowngrades_BalancedMode) {
   const int kFramerateFps = 30;
   const int kWidth = 1280;
   const int kHeight = 720;

   // We rely on the automatic resolution adaptation, but we handle framerate
   // adaptation manually by mocking the stats proxy.
   video_source_.set_adaptation_enabled(true);

   // Enable BALANCED preference, no initial limitation.
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);
   video_stream_encoder_->SetSource(&video_source_,
                                    webrtc::DegradationPreference::BALANCED);
   EXPECT_THAT(video_source_.sink_wants(), UnlimitedSinkWants());
   EXPECT_FALSE(stats_proxy_->GetStats().cpu_limited_resolution);
   EXPECT_FALSE(stats_proxy_->GetStats().cpu_limited_framerate);
   EXPECT_EQ(0, stats_proxy_->GetStats().number_of_cpu_adapt_changes);

   // Adapt down as far as possible.
   rtc::VideoSinkWants last_wants;
   int64_t t = 1;
   int loop_count = 0;
   do {
     ++loop_count;
     last_wants = video_source_.sink_wants();

     // Simulate the framerate we've been asked to adapt to.
     const int fps = std::min(kFramerateFps, last_wants.max_framerate_fps);
     const int frame_interval_ms = rtc::kNumMillisecsPerSec / fps;
     VideoSendStream::Stats mock_stats = stats_proxy_->GetStats();
     mock_stats.input_frame_rate = fps;
     stats_proxy_->SetMockStats(mock_stats);

     video_source_.IncomingCapturedFrame(CreateFrame(t, kWidth, kHeight));
     sink_.WaitForEncodedFrame(t);
     t += frame_interval_ms;

     video_stream_encoder_->TriggerCpuOveruse();
     EXPECT_THAT(
         video_source_.sink_wants(),
         FpsInRangeForPixelsInBalanced(*video_source_.last_sent_width() *
                                       *video_source_.last_sent_height()));
   } while (video_source_.sink_wants().max_pixel_count <
                last_wants.max_pixel_count ||
            video_source_.sink_wants().max_framerate_fps <
                last_wants.max_framerate_fps);

   // Verify that we've adapted all the way down.
   stats_proxy_->ResetMockStats();
   EXPECT_TRUE(stats_proxy_->GetStats().cpu_limited_resolution);
   EXPECT_TRUE(stats_proxy_->GetStats().cpu_limited_framerate);
   EXPECT_EQ(loop_count - 1,
             stats_proxy_->GetStats().number_of_cpu_adapt_changes);
   EXPECT_EQ(kMinPixelsPerFrame, *video_source_.last_sent_width() *
                                     *video_source_.last_sent_height());
   EXPECT_EQ(kMinBalancedFramerateFps,
             video_source_.sink_wants().max_framerate_fps);

   // Adapt back up the same number of times we adapted down.
   for (int i = 0; i < loop_count - 1; ++i) {
     last_wants = video_source_.sink_wants();

     // Simulate the framerate we've been asked to adapt to.
     const int fps = std::min(kFramerateFps, last_wants.max_framerate_fps);
     const int frame_interval_ms = rtc::kNumMillisecsPerSec / fps;
     VideoSendStream::Stats mock_stats = stats_proxy_->GetStats();
     mock_stats.input_frame_rate = fps;
     stats_proxy_->SetMockStats(mock_stats);

     video_source_.IncomingCapturedFrame(CreateFrame(t, kWidth, kHeight));
     sink_.WaitForEncodedFrame(t);
     t += frame_interval_ms;

     video_stream_encoder_->TriggerCpuUnderuse();
     EXPECT_THAT(
         video_source_.sink_wants(),
         FpsInRangeForPixelsInBalanced(*video_source_.last_sent_width() *
                                       *video_source_.last_sent_height()));
     EXPECT_TRUE(video_source_.sink_wants().max_pixel_count >
                     last_wants.max_pixel_count ||
                 video_source_.sink_wants().max_framerate_fps >
                     last_wants.max_framerate_fps);
   }

   EXPECT_THAT(video_source_.sink_wants(), FpsMaxResolutionMax());
   stats_proxy_->ResetMockStats();
   EXPECT_FALSE(stats_proxy_->GetStats().cpu_limited_resolution);
   EXPECT_FALSE(stats_proxy_->GetStats().cpu_limited_framerate);
   EXPECT_EQ((loop_count - 1) * 2,
             stats_proxy_->GetStats().number_of_cpu_adapt_changes);

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest,
        SinkWantsNotChangedByResourceLimitedBeforeDegradationPreferenceChange) {
   video_stream_encoder_->OnBitrateUpdated(kTargetBitrate, kTargetBitrate,
                                           kTargetBitrate, 0, 0, 0);
   EXPECT_THAT(video_source_.sink_wants(), UnlimitedSinkWants());

   const int kFrameWidth = 1280;
   const int kFrameHeight = 720;

   int64_t ntp_time = kFrameIntervalMs;

   // Force an input frame rate to be available, or the adaptation call won't
   // know what framerate to adapt form.
   const int kInputFps = 30;
   VideoSendStream::Stats stats = stats_proxy_->GetStats();
   stats.input_frame_rate = kInputFps;
   stats_proxy_->SetMockStats(stats);

   video_source_.set_adaptation_enabled(true);
   video_stream_encoder_->SetSource(
       &video_source_, webrtc::DegradationPreference::MAINTAIN_RESOLUTION);
   EXPECT_THAT(video_source_.sink_wants(), UnlimitedSinkWants());
   video_source_.IncomingCapturedFrame(
       CreateFrame(ntp_time, kFrameWidth, kFrameHeight));
   sink_.WaitForEncodedFrame(ntp_time);
   ntp_time += kFrameIntervalMs;

   // Trigger CPU overuse.
   video_stream_encoder_->TriggerCpuOveruse();
   video_source_.IncomingCapturedFrame(
       CreateFrame(ntp_time, kFrameWidth, kFrameHeight));
   sink_.WaitForEncodedFrame(ntp_time);
   ntp_time += kFrameIntervalMs;

   EXPECT_FALSE(video_source_.sink_wants().target_pixel_count);
   EXPECT_EQ(std::numeric_limits<int>::max(),
             video_source_.sink_wants().max_pixel_count);
   // Some framerate constraint should be set.
   int restricted_fps = video_source_.sink_wants().max_framerate_fps;
   EXPECT_LT(restricted_fps, kInputFps);
   video_source_.IncomingCapturedFrame(
       CreateFrame(ntp_time, kFrameWidth, kFrameHeight));
   sink_.WaitForEncodedFrame(ntp_time);
   ntp_time += 100;

   video_stream_encoder_->SetSourceAndWaitForRestrictionsUpdated(
       &video_source_, webrtc::DegradationPreference::MAINTAIN_FRAMERATE);
   // Give the encoder queue time to process the change in degradation preference
   // by waiting for an encoded frame.
   video_source_.IncomingCapturedFrame(
       CreateFrame(ntp_time, kFrameWidth, kFrameHeight));
   sink_.WaitForEncodedFrame(ntp_time);
   ntp_time += kFrameIntervalMs;

   video_stream_encoder_->TriggerQualityLow();
   video_source_.IncomingCapturedFrame(
       CreateFrame(ntp_time, kFrameWidth, kFrameHeight));
   sink_.WaitForEncodedFrame(ntp_time);
   ntp_time += kFrameIntervalMs;

   // Some resolution constraint should be set.
   EXPECT_FALSE(video_source_.sink_wants().target_pixel_count);
   EXPECT_LT(video_source_.sink_wants().max_pixel_count,
             kFrameWidth * kFrameHeight);
   EXPECT_EQ(video_source_.sink_wants().max_framerate_fps, kInputFps);

   int pixel_count = video_source_.sink_wants().max_pixel_count;
   // Triggering a CPU underuse should not change the sink wants since it has
   // not been overused for resolution since we changed degradation preference.
   video_stream_encoder_->TriggerCpuUnderuse();
   video_source_.IncomingCapturedFrame(
       CreateFrame(ntp_time, kFrameWidth, kFrameHeight));
   sink_.WaitForEncodedFrame(ntp_time);
   ntp_time += kFrameIntervalMs;
   EXPECT_EQ(video_source_.sink_wants().max_pixel_count, pixel_count);
   EXPECT_EQ(video_source_.sink_wants().max_framerate_fps, kInputFps);

   // Change the degradation preference back. CPU underuse should not adapt since
   // QP is most limited.
   video_stream_encoder_->SetSourceAndWaitForRestrictionsUpdated(
       &video_source_, webrtc::DegradationPreference::MAINTAIN_RESOLUTION);
   video_source_.IncomingCapturedFrame(
       CreateFrame(ntp_time, kFrameWidth, kFrameHeight));
   sink_.WaitForEncodedFrame(ntp_time);
   ntp_time += 100;
   // Resolution adaptations is gone after changing degradation preference.
   EXPECT_FALSE(video_source_.sink_wants().target_pixel_count);
   EXPECT_EQ(std::numeric_limits<int>::max(),
             video_source_.sink_wants().max_pixel_count);
   // The fps adaptation from above is now back.
   EXPECT_EQ(video_source_.sink_wants().max_framerate_fps, restricted_fps);

   // Trigger CPU underuse.
   video_stream_encoder_->TriggerCpuUnderuse();
   video_source_.IncomingCapturedFrame(
       CreateFrame(ntp_time, kFrameWidth, kFrameHeight));
   sink_.WaitForEncodedFrame(ntp_time);
   ntp_time += kFrameIntervalMs;
   EXPECT_EQ(video_source_.sink_wants().max_framerate_fps, restricted_fps);

   // Trigger QP underuse, fps should return to normal.
   video_stream_encoder_->TriggerQualityHigh();
   video_source_.IncomingCapturedFrame(
       CreateFrame(ntp_time, kFrameWidth, kFrameHeight));
   sink_.WaitForEncodedFrame(ntp_time);
   ntp_time += kFrameIntervalMs;
   EXPECT_THAT(video_source_.sink_wants(), FpsMax());

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest, SinkWantsStoredByDegradationPreference) {
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);
   EXPECT_THAT(video_source_.sink_wants(), UnlimitedSinkWants());

   const int kFrameWidth = 1280;
   const int kFrameHeight = 720;

   int64_t frame_timestamp = 1;

   video_source_.IncomingCapturedFrame(
       CreateFrame(frame_timestamp, kFrameWidth, kFrameHeight));
   WaitForEncodedFrame(frame_timestamp);
   frame_timestamp += kFrameIntervalMs;

   // Trigger CPU overuse.
   video_stream_encoder_->TriggerCpuOveruse();
   video_source_.IncomingCapturedFrame(
       CreateFrame(frame_timestamp, kFrameWidth, kFrameHeight));
   WaitForEncodedFrame(frame_timestamp);
   frame_timestamp += kFrameIntervalMs;

   // Default degradation preference is maintain-framerate, so will lower max
   // wanted resolution.
   EXPECT_FALSE(video_source_.sink_wants().target_pixel_count);
   EXPECT_LT(video_source_.sink_wants().max_pixel_count,
             kFrameWidth * kFrameHeight);
   EXPECT_EQ(kDefaultFramerate, video_source_.sink_wants().max_framerate_fps);

   // Set new source, switch to maintain-resolution.
   test::FrameForwarder new_video_source;
   video_stream_encoder_->SetSourceAndWaitForRestrictionsUpdated(
       &new_video_source, webrtc::DegradationPreference::MAINTAIN_RESOLUTION);
   // Give the encoder queue time to process the change in degradation preference
   // by waiting for an encoded frame.
   new_video_source.IncomingCapturedFrame(
       CreateFrame(frame_timestamp, kFrameWidth, kFrameWidth));
   sink_.WaitForEncodedFrame(frame_timestamp);
   frame_timestamp += kFrameIntervalMs;
   // Initially no degradation registered.
   EXPECT_THAT(new_video_source.sink_wants(), FpsMaxResolutionMax());

   // Force an input frame rate to be available, or the adaptation call won't
   // know what framerate to adapt form.
   const int kInputFps = 30;
   VideoSendStream::Stats stats = stats_proxy_->GetStats();
   stats.input_frame_rate = kInputFps;
   stats_proxy_->SetMockStats(stats);

   video_stream_encoder_->TriggerCpuOveruse();
   new_video_source.IncomingCapturedFrame(
       CreateFrame(frame_timestamp, kFrameWidth, kFrameHeight));
   WaitForEncodedFrame(frame_timestamp);
   frame_timestamp += kFrameIntervalMs;

   // Some framerate constraint should be set.
   EXPECT_FALSE(new_video_source.sink_wants().target_pixel_count);
   EXPECT_EQ(std::numeric_limits<int>::max(),
             new_video_source.sink_wants().max_pixel_count);
   EXPECT_LT(new_video_source.sink_wants().max_framerate_fps, kInputFps);

   // Turn off degradation completely.
   video_stream_encoder_->SetSourceAndWaitForRestrictionsUpdated(
       &new_video_source, webrtc::DegradationPreference::DISABLED);
   // Give the encoder queue time to process the change in degradation preference
   // by waiting for an encoded frame.
   new_video_source.IncomingCapturedFrame(
       CreateFrame(frame_timestamp, kFrameWidth, kFrameWidth));
   sink_.WaitForEncodedFrame(frame_timestamp);
   frame_timestamp += kFrameIntervalMs;
   EXPECT_THAT(new_video_source.sink_wants(), FpsMaxResolutionMax());

   video_stream_encoder_->TriggerCpuOveruse();
   new_video_source.IncomingCapturedFrame(
       CreateFrame(frame_timestamp, kFrameWidth, kFrameHeight));
   WaitForEncodedFrame(frame_timestamp);
   frame_timestamp += kFrameIntervalMs;

   // Still no degradation.
   EXPECT_THAT(new_video_source.sink_wants(), FpsMaxResolutionMax());

   // Calling SetSource with resolution scaling enabled apply the old SinkWants.
   video_stream_encoder_->SetSourceAndWaitForRestrictionsUpdated(
       &new_video_source, webrtc::DegradationPreference::MAINTAIN_FRAMERATE);
   // Give the encoder queue time to process the change in degradation preference
   // by waiting for an encoded frame.
   new_video_source.IncomingCapturedFrame(
       CreateFrame(frame_timestamp, kFrameWidth, kFrameWidth));
   sink_.WaitForEncodedFrame(frame_timestamp);
   frame_timestamp += kFrameIntervalMs;
   EXPECT_LT(new_video_source.sink_wants().max_pixel_count,
             kFrameWidth * kFrameHeight);
   EXPECT_FALSE(new_video_source.sink_wants().target_pixel_count);
   EXPECT_EQ(kDefaultFramerate, new_video_source.sink_wants().max_framerate_fps);

   // Calling SetSource with framerate scaling enabled apply the old SinkWants.
   video_stream_encoder_->SetSourceAndWaitForRestrictionsUpdated(
       &new_video_source, webrtc::DegradationPreference::MAINTAIN_RESOLUTION);
   // Give the encoder queue time to process the change in degradation preference
   // by waiting for an encoded frame.
   new_video_source.IncomingCapturedFrame(
       CreateFrame(frame_timestamp, kFrameWidth, kFrameWidth));
   sink_.WaitForEncodedFrame(frame_timestamp);
   frame_timestamp += kFrameIntervalMs;
   EXPECT_FALSE(new_video_source.sink_wants().target_pixel_count);
   EXPECT_EQ(std::numeric_limits<int>::max(),
             new_video_source.sink_wants().max_pixel_count);
   EXPECT_LT(new_video_source.sink_wants().max_framerate_fps, kInputFps);

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest, StatsTracksQualityAdaptationStats) {
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);

   const int kWidth = 1280;
   const int kHeight = 720;
   video_source_.IncomingCapturedFrame(CreateFrame(1, kWidth, kHeight));
   WaitForEncodedFrame(1);
   VideoSendStream::Stats stats = stats_proxy_->GetStats();
   EXPECT_FALSE(stats.bw_limited_resolution);
   EXPECT_EQ(0, stats.number_of_quality_adapt_changes);

   // Trigger adapt down.
   video_stream_encoder_->TriggerQualityLow();
   video_source_.IncomingCapturedFrame(CreateFrame(2, kWidth, kHeight));
   WaitForEncodedFrame(2);

   stats = stats_proxy_->GetStats();
   EXPECT_TRUE(stats.bw_limited_resolution);
   EXPECT_EQ(1, stats.number_of_quality_adapt_changes);

   // Trigger adapt up.
   video_stream_encoder_->TriggerQualityHigh();
   video_source_.IncomingCapturedFrame(CreateFrame(3, kWidth, kHeight));
   WaitForEncodedFrame(3);

   stats = stats_proxy_->GetStats();
   EXPECT_FALSE(stats.bw_limited_resolution);
   EXPECT_EQ(2, stats.number_of_quality_adapt_changes);
   EXPECT_EQ(0, stats.number_of_cpu_adapt_changes);

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest, StatsTracksCpuAdaptationStats) {
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);

   const int kWidth = 1280;
   const int kHeight = 720;
   video_source_.IncomingCapturedFrame(CreateFrame(1, kWidth, kHeight));
   WaitForEncodedFrame(1);
   VideoSendStream::Stats stats = stats_proxy_->GetStats();
   EXPECT_FALSE(stats.cpu_limited_resolution);
   EXPECT_EQ(0, stats.number_of_cpu_adapt_changes);

   // Trigger CPU overuse.
   video_stream_encoder_->TriggerCpuOveruse();
   video_source_.IncomingCapturedFrame(CreateFrame(2, kWidth, kHeight));
   WaitForEncodedFrame(2);

   stats = stats_proxy_->GetStats();
   EXPECT_TRUE(stats.cpu_limited_resolution);
   EXPECT_EQ(1, stats.number_of_cpu_adapt_changes);

   // Trigger CPU normal use.
   video_stream_encoder_->TriggerCpuUnderuse();
   video_source_.IncomingCapturedFrame(CreateFrame(3, kWidth, kHeight));
   WaitForEncodedFrame(3);

   stats = stats_proxy_->GetStats();
   EXPECT_FALSE(stats.cpu_limited_resolution);
   EXPECT_EQ(2, stats.number_of_cpu_adapt_changes);
   EXPECT_EQ(0, stats.number_of_quality_adapt_changes);

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest, SwitchingSourceKeepsCpuAdaptation) {
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);

   const int kWidth = 1280;
   const int kHeight = 720;
   video_source_.IncomingCapturedFrame(CreateFrame(1, kWidth, kHeight));
   WaitForEncodedFrame(1);
   VideoSendStream::Stats stats = stats_proxy_->GetStats();
   EXPECT_FALSE(stats.bw_limited_resolution);
   EXPECT_FALSE(stats.cpu_limited_resolution);
   EXPECT_EQ(0, stats.number_of_cpu_adapt_changes);

   // Trigger CPU overuse.
   video_stream_encoder_->TriggerCpuOveruse();
   video_source_.IncomingCapturedFrame(CreateFrame(2, kWidth, kHeight));
   WaitForEncodedFrame(2);
   stats = stats_proxy_->GetStats();
   EXPECT_FALSE(stats.bw_limited_resolution);
   EXPECT_TRUE(stats.cpu_limited_resolution);
   EXPECT_EQ(1, stats.number_of_cpu_adapt_changes);

   // Set new source with adaptation still enabled.
   test::FrameForwarder new_video_source;
   video_stream_encoder_->SetSource(
       &new_video_source, webrtc::DegradationPreference::MAINTAIN_FRAMERATE);

   new_video_source.IncomingCapturedFrame(CreateFrame(3, kWidth, kHeight));
   WaitForEncodedFrame(3);
   stats = stats_proxy_->GetStats();
   EXPECT_FALSE(stats.bw_limited_resolution);
   EXPECT_TRUE(stats.cpu_limited_resolution);
   EXPECT_EQ(1, stats.number_of_cpu_adapt_changes);

   // Set adaptation disabled.
   video_stream_encoder_->SetSource(&new_video_source,
                                    webrtc::DegradationPreference::DISABLED);

   new_video_source.IncomingCapturedFrame(CreateFrame(4, kWidth, kHeight));
   WaitForEncodedFrame(4);
   stats = stats_proxy_->GetStats();
   EXPECT_FALSE(stats.bw_limited_resolution);
   EXPECT_FALSE(stats.cpu_limited_resolution);
   EXPECT_EQ(1, stats.number_of_cpu_adapt_changes);

   // Set adaptation back to enabled.
   video_stream_encoder_->SetSource(
       &new_video_source, webrtc::DegradationPreference::MAINTAIN_FRAMERATE);

   new_video_source.IncomingCapturedFrame(CreateFrame(5, kWidth, kHeight));
   WaitForEncodedFrame(5);
   stats = stats_proxy_->GetStats();
   EXPECT_FALSE(stats.bw_limited_resolution);
   EXPECT_TRUE(stats.cpu_limited_resolution);
   EXPECT_EQ(1, stats.number_of_cpu_adapt_changes);

   // Trigger CPU normal use.
   video_stream_encoder_->TriggerCpuUnderuse();
   new_video_source.IncomingCapturedFrame(CreateFrame(6, kWidth, kHeight));
   WaitForEncodedFrame(6);
   stats = stats_proxy_->GetStats();
   EXPECT_FALSE(stats.bw_limited_resolution);
   EXPECT_FALSE(stats.cpu_limited_resolution);
   EXPECT_EQ(2, stats.number_of_cpu_adapt_changes);
   EXPECT_EQ(0, stats.number_of_quality_adapt_changes);

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest, SwitchingSourceKeepsQualityAdaptation) {
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);

   const int kWidth = 1280;
   const int kHeight = 720;
   video_source_.IncomingCapturedFrame(CreateFrame(1, kWidth, kHeight));
   WaitForEncodedFrame(1);
   VideoSendStream::Stats stats = stats_proxy_->GetStats();
   EXPECT_FALSE(stats.bw_limited_resolution);
   EXPECT_FALSE(stats.bw_limited_framerate);
   EXPECT_EQ(0, stats.number_of_quality_adapt_changes);

   // Set new source with adaptation still enabled.
   test::FrameForwarder new_video_source;
   video_stream_encoder_->SetSource(&new_video_source,
                                    webrtc::DegradationPreference::BALANCED);

   new_video_source.IncomingCapturedFrame(CreateFrame(2, kWidth, kHeight));
   WaitForEncodedFrame(2);
   stats = stats_proxy_->GetStats();
   EXPECT_FALSE(stats.bw_limited_resolution);
   EXPECT_FALSE(stats.bw_limited_framerate);
   EXPECT_EQ(0, stats.number_of_quality_adapt_changes);

   // Trigger adapt down.
   video_stream_encoder_->TriggerQualityLow();
   new_video_source.IncomingCapturedFrame(CreateFrame(3, kWidth, kHeight));
   WaitForEncodedFrame(3);
   stats = stats_proxy_->GetStats();
   EXPECT_TRUE(stats.bw_limited_resolution);
   EXPECT_FALSE(stats.bw_limited_framerate);
   EXPECT_EQ(1, stats.number_of_quality_adapt_changes);

   // Set new source with adaptation still enabled.
   video_stream_encoder_->SetSource(&new_video_source,
                                    webrtc::DegradationPreference::BALANCED);

   new_video_source.IncomingCapturedFrame(CreateFrame(4, kWidth, kHeight));
   WaitForEncodedFrame(4);
   stats = stats_proxy_->GetStats();
   EXPECT_TRUE(stats.bw_limited_resolution);
   EXPECT_FALSE(stats.bw_limited_framerate);
   EXPECT_EQ(1, stats.number_of_quality_adapt_changes);

   // Disable resolution scaling.
   video_stream_encoder_->SetSource(
       &new_video_source, webrtc::DegradationPreference::MAINTAIN_RESOLUTION);

   new_video_source.IncomingCapturedFrame(CreateFrame(5, kWidth, kHeight));
   WaitForEncodedFrame(5);
   stats = stats_proxy_->GetStats();
   EXPECT_FALSE(stats.bw_limited_resolution);
   EXPECT_FALSE(stats.bw_limited_framerate);
   EXPECT_EQ(1, stats.number_of_quality_adapt_changes);
   EXPECT_EQ(0, stats.number_of_cpu_adapt_changes);

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest,
        QualityAdaptationStatsAreResetWhenScalerIsDisabled) {
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);

   const int kWidth = 1280;
   const int kHeight = 720;
   int64_t timestamp_ms = kFrameIntervalMs;
   video_source_.set_adaptation_enabled(true);
   video_source_.IncomingCapturedFrame(
       CreateFrame(timestamp_ms, kWidth, kHeight));
   WaitForEncodedFrame(timestamp_ms);
   EXPECT_FALSE(stats_proxy_->GetStats().cpu_limited_resolution);
   EXPECT_FALSE(stats_proxy_->GetStats().bw_limited_resolution);
   EXPECT_EQ(0, stats_proxy_->GetStats().number_of_cpu_adapt_changes);

   // Trigger adapt down.
   video_stream_encoder_->TriggerQualityLow();
   timestamp_ms += kFrameIntervalMs;
   video_source_.IncomingCapturedFrame(
       CreateFrame(timestamp_ms, kWidth, kHeight));
   WaitForEncodedFrame(timestamp_ms);
   EXPECT_FALSE(stats_proxy_->GetStats().cpu_limited_resolution);
   EXPECT_TRUE(stats_proxy_->GetStats().bw_limited_resolution);
   EXPECT_EQ(0, stats_proxy_->GetStats().number_of_cpu_adapt_changes);

   // Trigger overuse.
   video_stream_encoder_->TriggerCpuOveruse();
   timestamp_ms += kFrameIntervalMs;
   video_source_.IncomingCapturedFrame(
       CreateFrame(timestamp_ms, kWidth, kHeight));
   WaitForEncodedFrame(timestamp_ms);
   EXPECT_TRUE(stats_proxy_->GetStats().cpu_limited_resolution);
   EXPECT_TRUE(stats_proxy_->GetStats().bw_limited_resolution);
   EXPECT_EQ(1, stats_proxy_->GetStats().number_of_cpu_adapt_changes);

   // Leave source unchanged, but disable quality scaler.
   fake_encoder_.SetQualityScaling(false);

   VideoEncoderConfig video_encoder_config;
   test::FillEncoderConfiguration(kVideoCodecVP8, 1, &video_encoder_config);
   // Make format different, to force recreation of encoder.
   video_encoder_config.video_format.parameters["foo"] = "foo";
   video_stream_encoder_->ConfigureEncoder(std::move(video_encoder_config),
                                           kMaxPayloadLength);
   timestamp_ms += kFrameIntervalMs;
   video_source_.IncomingCapturedFrame(
       CreateFrame(timestamp_ms, kWidth, kHeight));
   WaitForEncodedFrame(timestamp_ms);
   EXPECT_TRUE(stats_proxy_->GetStats().cpu_limited_resolution);
   EXPECT_FALSE(stats_proxy_->GetStats().bw_limited_resolution);
   EXPECT_EQ(1, stats_proxy_->GetStats().number_of_cpu_adapt_changes);

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest,
        StatsTracksCpuAdaptationStatsWhenSwitchingSource_Balanced) {
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);

   const int kWidth = 1280;
   const int kHeight = 720;
   int sequence = 1;

   // Enable BALANCED preference, no initial limitation.
   test::FrameForwarder source;
   video_stream_encoder_->SetSource(&source,
                                    webrtc::DegradationPreference::BALANCED);
   source.IncomingCapturedFrame(CreateFrame(sequence, kWidth, kHeight));
   WaitForEncodedFrame(sequence++);
   VideoSendStream::Stats stats = stats_proxy_->GetStats();
   EXPECT_FALSE(stats.cpu_limited_resolution);
   EXPECT_FALSE(stats.cpu_limited_framerate);
   EXPECT_EQ(0, stats.number_of_cpu_adapt_changes);

   // Trigger CPU overuse, should now adapt down.
   video_stream_encoder_->TriggerCpuOveruse();
   source.IncomingCapturedFrame(CreateFrame(sequence, kWidth, kHeight));
   WaitForEncodedFrame(sequence++);
   stats = stats_proxy_->GetStats();
   EXPECT_EQ(1, stats.number_of_cpu_adapt_changes);

   // Set new degradation preference should clear restrictions since we changed
   // from BALANCED.
   video_stream_encoder_->SetSourceAndWaitForRestrictionsUpdated(
       &source, webrtc::DegradationPreference::MAINTAIN_FRAMERATE);
   source.IncomingCapturedFrame(CreateFrame(sequence, kWidth, kHeight));
   WaitForEncodedFrame(sequence++);
   stats = stats_proxy_->GetStats();
   EXPECT_FALSE(stats.cpu_limited_resolution);
   EXPECT_FALSE(stats.cpu_limited_framerate);
   EXPECT_EQ(1, stats.number_of_cpu_adapt_changes);

   // Force an input frame rate to be available, or the adaptation call won't
   // know what framerate to adapt from.
   VideoSendStream::Stats mock_stats = stats_proxy_->GetStats();
   mock_stats.input_frame_rate = 30;
   stats_proxy_->SetMockStats(mock_stats);
   video_stream_encoder_->TriggerCpuOveruse();
   stats_proxy_->ResetMockStats();
   source.IncomingCapturedFrame(CreateFrame(sequence, kWidth, kHeight));
   WaitForEncodedFrame(sequence++);

   // We have now adapted once.
   stats = stats_proxy_->GetStats();
   EXPECT_EQ(2, stats.number_of_cpu_adapt_changes);

   // Back to BALANCED, should clear the restrictions again.
   video_stream_encoder_->SetSourceAndWaitForRestrictionsUpdated(
       &source, webrtc::DegradationPreference::BALANCED);
   source.IncomingCapturedFrame(CreateFrame(sequence, kWidth, kHeight));
   WaitForEncodedFrame(sequence++);
   stats = stats_proxy_->GetStats();
   EXPECT_FALSE(stats.cpu_limited_resolution);
   EXPECT_FALSE(stats.cpu_limited_framerate);
   EXPECT_EQ(2, stats.number_of_cpu_adapt_changes);

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest,
        StatsTracksCpuAdaptationStatsWhenSwitchingSource) {
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);

   const int kWidth = 1280;
   const int kHeight = 720;
   int sequence = 1;

   video_source_.IncomingCapturedFrame(CreateFrame(sequence, kWidth, kHeight));
   WaitForEncodedFrame(sequence++);
   VideoSendStream::Stats stats = stats_proxy_->GetStats();
   EXPECT_FALSE(stats.cpu_limited_resolution);
   EXPECT_FALSE(stats.cpu_limited_framerate);
   EXPECT_EQ(0, stats.number_of_cpu_adapt_changes);

   // Trigger CPU overuse, should now adapt down.
   video_stream_encoder_->TriggerCpuOveruse();
   video_source_.IncomingCapturedFrame(CreateFrame(sequence, kWidth, kHeight));
   WaitForEncodedFrame(sequence++);
   stats = stats_proxy_->GetStats();
   EXPECT_TRUE(stats.cpu_limited_resolution);
   EXPECT_FALSE(stats.cpu_limited_framerate);
   EXPECT_EQ(1, stats.number_of_cpu_adapt_changes);

   // Set new source with adaptation still enabled.
   test::FrameForwarder new_video_source;
   video_stream_encoder_->SetSource(
       &new_video_source, webrtc::DegradationPreference::MAINTAIN_FRAMERATE);

   new_video_source.IncomingCapturedFrame(
       CreateFrame(sequence, kWidth, kHeight));
   WaitForEncodedFrame(sequence++);
   stats = stats_proxy_->GetStats();
   EXPECT_TRUE(stats.cpu_limited_resolution);
   EXPECT_FALSE(stats.cpu_limited_framerate);
   EXPECT_EQ(1, stats.number_of_cpu_adapt_changes);

   // Set cpu adaptation by frame dropping.
   video_stream_encoder_->SetSource(
       &new_video_source, webrtc::DegradationPreference::MAINTAIN_RESOLUTION);
   new_video_source.IncomingCapturedFrame(
       CreateFrame(sequence, kWidth, kHeight));
   WaitForEncodedFrame(sequence++);
   stats = stats_proxy_->GetStats();
   // Not adapted at first.
   EXPECT_FALSE(stats.cpu_limited_resolution);
   EXPECT_FALSE(stats.cpu_limited_framerate);
   EXPECT_EQ(1, stats.number_of_cpu_adapt_changes);

   // Force an input frame rate to be available, or the adaptation call won't
   // know what framerate to adapt from.
   VideoSendStream::Stats mock_stats = stats_proxy_->GetStats();
   mock_stats.input_frame_rate = 30;
   stats_proxy_->SetMockStats(mock_stats);
   video_stream_encoder_->TriggerCpuOveruse();
   stats_proxy_->ResetMockStats();

   new_video_source.IncomingCapturedFrame(
       CreateFrame(sequence, kWidth, kHeight));
   WaitForEncodedFrame(sequence++);

   // Framerate now adapted.
   stats = stats_proxy_->GetStats();
   EXPECT_FALSE(stats.cpu_limited_resolution);
   EXPECT_TRUE(stats.cpu_limited_framerate);
   EXPECT_EQ(2, stats.number_of_cpu_adapt_changes);

   // Disable CPU adaptation.
   video_stream_encoder_->SetSource(&new_video_source,
                                    webrtc::DegradationPreference::DISABLED);
   new_video_source.IncomingCapturedFrame(
       CreateFrame(sequence, kWidth, kHeight));
   WaitForEncodedFrame(sequence++);

   stats = stats_proxy_->GetStats();
   EXPECT_FALSE(stats.cpu_limited_resolution);
   EXPECT_FALSE(stats.cpu_limited_framerate);
   EXPECT_EQ(2, stats.number_of_cpu_adapt_changes);

   // Try to trigger overuse. Should not succeed.
   stats_proxy_->SetMockStats(mock_stats);
   video_stream_encoder_->TriggerCpuOveruse();
   stats_proxy_->ResetMockStats();

   stats = stats_proxy_->GetStats();
   EXPECT_FALSE(stats.cpu_limited_resolution);
   EXPECT_FALSE(stats.cpu_limited_framerate);
   EXPECT_EQ(2, stats.number_of_cpu_adapt_changes);

   // Switch back the source with resolution adaptation enabled.
   video_stream_encoder_->SetSource(
       &video_source_, webrtc::DegradationPreference::MAINTAIN_FRAMERATE);
   video_source_.IncomingCapturedFrame(CreateFrame(sequence, kWidth, kHeight));
   WaitForEncodedFrame(sequence++);
   stats = stats_proxy_->GetStats();
   EXPECT_TRUE(stats.cpu_limited_resolution);
   EXPECT_FALSE(stats.cpu_limited_framerate);
   EXPECT_EQ(2, stats.number_of_cpu_adapt_changes);

   // Trigger CPU normal usage.
   video_stream_encoder_->TriggerCpuUnderuse();
   video_source_.IncomingCapturedFrame(CreateFrame(sequence, kWidth, kHeight));
   WaitForEncodedFrame(sequence++);
   stats = stats_proxy_->GetStats();
   EXPECT_FALSE(stats.cpu_limited_resolution);
   EXPECT_FALSE(stats.cpu_limited_framerate);
   EXPECT_EQ(3, stats.number_of_cpu_adapt_changes);

   // Back to the source with adaptation off, set it back to maintain-resolution.
   video_stream_encoder_->SetSource(
       &new_video_source, webrtc::DegradationPreference::MAINTAIN_RESOLUTION);
   new_video_source.IncomingCapturedFrame(
       CreateFrame(sequence, kWidth, kHeight));
   WaitForEncodedFrame(sequence++);
   stats = stats_proxy_->GetStats();
   // Disabled, since we previously switched the source to disabled.
   EXPECT_FALSE(stats.cpu_limited_resolution);
   EXPECT_TRUE(stats.cpu_limited_framerate);
   EXPECT_EQ(3, stats.number_of_cpu_adapt_changes);

   // Trigger CPU normal usage.
   video_stream_encoder_->TriggerCpuUnderuse();
   new_video_source.IncomingCapturedFrame(
       CreateFrame(sequence, kWidth, kHeight));
   WaitForEncodedFrame(sequence++);
   stats = stats_proxy_->GetStats();
   EXPECT_FALSE(stats.cpu_limited_resolution);
   EXPECT_FALSE(stats.cpu_limited_framerate);
   EXPECT_EQ(4, stats.number_of_cpu_adapt_changes);
   EXPECT_EQ(0, stats.number_of_quality_adapt_changes);

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest,
        ScalingUpAndDownDoesNothingWithMaintainResolution) {
   const int kWidth = 1280;
   const int kHeight = 720;
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);

   // Expect no scaling to begin with.
   EXPECT_THAT(video_source_.sink_wants(), UnlimitedSinkWants());

   video_source_.IncomingCapturedFrame(CreateFrame(1, kWidth, kHeight));
   WaitForEncodedFrame(1);

   // Trigger scale down.
   video_stream_encoder_->TriggerQualityLow();

   video_source_.IncomingCapturedFrame(CreateFrame(2, kWidth, kHeight));
   WaitForEncodedFrame(2);

   // Expect a scale down.
   EXPECT_TRUE(video_source_.sink_wants().max_pixel_count);
   EXPECT_LT(video_source_.sink_wants().max_pixel_count, kWidth * kHeight);

   // Set resolution scaling disabled.
   test::FrameForwarder new_video_source;
   video_stream_encoder_->SetSource(
       &new_video_source, webrtc::DegradationPreference::MAINTAIN_RESOLUTION);

   // Trigger scale down.
   video_stream_encoder_->TriggerQualityLow();
   new_video_source.IncomingCapturedFrame(CreateFrame(3, kWidth, kHeight));
   WaitForEncodedFrame(3);

   // Expect no scaling.
   EXPECT_EQ(std::numeric_limits<int>::max(),
             new_video_source.sink_wants().max_pixel_count);

   // Trigger scale up.
   video_stream_encoder_->TriggerQualityHigh();
   new_video_source.IncomingCapturedFrame(CreateFrame(4, kWidth, kHeight));
   WaitForEncodedFrame(4);

   // Expect nothing to change, still no scaling.
   EXPECT_EQ(std::numeric_limits<int>::max(),
             new_video_source.sink_wants().max_pixel_count);

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest,
        SkipsSameAdaptDownRequest_MaintainFramerateMode) {
   const int kWidth = 1280;
   const int kHeight = 720;
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);

   // Enable MAINTAIN_FRAMERATE preference, no initial limitation.
   test::FrameForwarder source;
   video_stream_encoder_->SetSource(
       &source, webrtc::DegradationPreference::MAINTAIN_FRAMERATE);

   source.IncomingCapturedFrame(CreateFrame(1, kWidth, kHeight));
   WaitForEncodedFrame(1);
   EXPECT_THAT(source.sink_wants(), FpsMaxResolutionMax());
   EXPECT_FALSE(stats_proxy_->GetStats().cpu_limited_resolution);
   EXPECT_EQ(0, stats_proxy_->GetStats().number_of_cpu_adapt_changes);

   // Trigger adapt down, expect scaled down resolution.
   video_stream_encoder_->TriggerCpuOveruse();
   EXPECT_THAT(source.sink_wants(),
               FpsMaxResolutionMatches(Lt(kWidth * kHeight)));
   const int kLastMaxPixelCount = source.sink_wants().max_pixel_count;
   EXPECT_TRUE(stats_proxy_->GetStats().cpu_limited_resolution);
   EXPECT_EQ(1, stats_proxy_->GetStats().number_of_cpu_adapt_changes);

   // Trigger adapt down for same input resolution, expect no change.
   video_stream_encoder_->TriggerCpuOveruse();
   EXPECT_EQ(kLastMaxPixelCount, source.sink_wants().max_pixel_count);
   EXPECT_TRUE(stats_proxy_->GetStats().cpu_limited_resolution);
   EXPECT_EQ(1, stats_proxy_->GetStats().number_of_cpu_adapt_changes);

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest, SkipsSameOrLargerAdaptDownRequest_BalancedMode) {
   const int kWidth = 1280;
   const int kHeight = 720;
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);

   // Enable BALANCED preference, no initial limitation.
   test::FrameForwarder source;
   video_stream_encoder_->SetSource(&source,
                                    webrtc::DegradationPreference::BALANCED);
   source.IncomingCapturedFrame(CreateFrame(1, kWidth, kHeight));
   sink_.WaitForEncodedFrame(1);
   EXPECT_THAT(source.sink_wants(), FpsMaxResolutionMax());

   // Trigger adapt down, expect scaled down resolution.
   video_stream_encoder_->TriggerQualityLow();
   EXPECT_THAT(source.sink_wants(),
               FpsMaxResolutionMatches(Lt(kWidth * kHeight)));
   EXPECT_TRUE(stats_proxy_->GetStats().bw_limited_resolution);
   EXPECT_EQ(1, stats_proxy_->GetStats().number_of_quality_adapt_changes);
   const int kLastMaxPixelCount = source.sink_wants().max_pixel_count;

   // Trigger adapt down for same input resolution, expect no change.
   source.IncomingCapturedFrame(CreateFrame(2, kWidth, kHeight));
   sink_.WaitForEncodedFrame(2);
   video_stream_encoder_->TriggerQualityLow();
   EXPECT_EQ(kLastMaxPixelCount, source.sink_wants().max_pixel_count);
   EXPECT_TRUE(stats_proxy_->GetStats().bw_limited_resolution);
   EXPECT_EQ(1, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   // Trigger adapt down for larger input resolution, expect no change.
   source.IncomingCapturedFrame(CreateFrame(3, kWidth + 1, kHeight + 1));
   sink_.WaitForEncodedFrame(3);
   video_stream_encoder_->TriggerQualityLow();
   EXPECT_EQ(kLastMaxPixelCount, source.sink_wants().max_pixel_count);
   EXPECT_TRUE(stats_proxy_->GetStats().bw_limited_resolution);
   EXPECT_EQ(1, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest,
        FpsCountReturnsToZeroForFewerAdaptationsUpThanDown) {
   const int kWidth = 640;
   const int kHeight = 360;
   const int64_t kFrameIntervalMs = 150;
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);

   // Enable BALANCED preference, no initial limitation.
   AdaptingFrameForwarder source(&time_controller_);
   source.set_adaptation_enabled(true);
   video_stream_encoder_->SetSource(&source,
                                    webrtc::DegradationPreference::BALANCED);

   int64_t timestamp_ms = kFrameIntervalMs;
   source.IncomingCapturedFrame(CreateFrame(timestamp_ms, kWidth, kHeight));
   sink_.WaitForEncodedFrame(kWidth, kHeight);
   EXPECT_THAT(source.sink_wants(), FpsMaxResolutionMax());
   EXPECT_FALSE(stats_proxy_->GetStats().bw_limited_resolution);
   EXPECT_FALSE(stats_proxy_->GetStats().bw_limited_framerate);
   EXPECT_EQ(0, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   // Trigger adapt down, expect reduced fps (640x360@15fps).
   video_stream_encoder_->TriggerQualityLow();
   timestamp_ms += kFrameIntervalMs;
   source.IncomingCapturedFrame(CreateFrame(timestamp_ms, kWidth, kHeight));
   sink_.WaitForEncodedFrame(timestamp_ms);
   EXPECT_THAT(source.sink_wants(),
               FpsMatchesResolutionMax(Lt(kDefaultFramerate)));
   EXPECT_FALSE(stats_proxy_->GetStats().bw_limited_resolution);
   EXPECT_TRUE(stats_proxy_->GetStats().bw_limited_framerate);
   EXPECT_EQ(1, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   // Source requests 270p, expect reduced resolution (480x270@15fps).
   source.OnOutputFormatRequest(480, 270);
   timestamp_ms += kFrameIntervalMs;
   source.IncomingCapturedFrame(CreateFrame(timestamp_ms, kWidth, kHeight));
   WaitForEncodedFrame(480, 270);
   EXPECT_EQ(1, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   // Trigger adapt down, expect reduced fps (480x270@10fps).
   video_stream_encoder_->TriggerQualityLow();
   timestamp_ms += kFrameIntervalMs;
   source.IncomingCapturedFrame(CreateFrame(timestamp_ms, kWidth, kHeight));
   sink_.WaitForEncodedFrame(timestamp_ms);
   EXPECT_THAT(source.sink_wants(), FpsLtResolutionEq(source.last_wants()));
   EXPECT_FALSE(stats_proxy_->GetStats().bw_limited_resolution);
   EXPECT_TRUE(stats_proxy_->GetStats().bw_limited_framerate);
   EXPECT_EQ(2, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   // Source requests QVGA, expect reduced resolution (320x180@10fps).
   source.OnOutputFormatRequest(320, 180);
   timestamp_ms += kFrameIntervalMs;
   source.IncomingCapturedFrame(CreateFrame(timestamp_ms, kWidth, kHeight));
   WaitForEncodedFrame(320, 180);
   EXPECT_EQ(2, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   // Trigger adapt down, expect reduced fps (320x180@7fps).
   video_stream_encoder_->TriggerQualityLow();
   timestamp_ms += kFrameIntervalMs;
   source.IncomingCapturedFrame(CreateFrame(timestamp_ms, kWidth, kHeight));
   sink_.WaitForEncodedFrame(timestamp_ms);
   EXPECT_THAT(source.sink_wants(), FpsLtResolutionEq(source.last_wants()));
   EXPECT_FALSE(stats_proxy_->GetStats().bw_limited_resolution);
   EXPECT_TRUE(stats_proxy_->GetStats().bw_limited_framerate);
   EXPECT_EQ(3, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   // Source requests VGA, expect increased resolution (640x360@7fps).
   source.OnOutputFormatRequest(640, 360);
   timestamp_ms += kFrameIntervalMs;
   source.IncomingCapturedFrame(CreateFrame(timestamp_ms, kWidth, kHeight));
   WaitForEncodedFrame(timestamp_ms);
   EXPECT_EQ(3, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   // Trigger adapt up, expect increased fps (640x360@(max-2)fps).
   video_stream_encoder_->TriggerQualityHigh();
   timestamp_ms += kFrameIntervalMs;
   source.IncomingCapturedFrame(CreateFrame(timestamp_ms, kWidth, kHeight));
   WaitForEncodedFrame(timestamp_ms);
   EXPECT_THAT(source.sink_wants(), FpsGtResolutionEq(source.last_wants()));
   EXPECT_FALSE(stats_proxy_->GetStats().bw_limited_resolution);
   EXPECT_TRUE(stats_proxy_->GetStats().bw_limited_framerate);
   EXPECT_EQ(4, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   // Trigger adapt up, expect increased fps (640x360@(max-1)fps).
   video_stream_encoder_->TriggerQualityHigh();
   timestamp_ms += kFrameIntervalMs;
   source.IncomingCapturedFrame(CreateFrame(timestamp_ms, kWidth, kHeight));
   WaitForEncodedFrame(timestamp_ms);
   EXPECT_THAT(source.sink_wants(), FpsGtResolutionEq(source.last_wants()));
   EXPECT_FALSE(stats_proxy_->GetStats().bw_limited_resolution);
   EXPECT_TRUE(stats_proxy_->GetStats().bw_limited_framerate);
   EXPECT_EQ(5, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   // Trigger adapt up, expect increased fps (640x360@maxfps).
   video_stream_encoder_->TriggerQualityHigh();
   timestamp_ms += kFrameIntervalMs;
   source.IncomingCapturedFrame(CreateFrame(timestamp_ms, kWidth, kHeight));
   WaitForEncodedFrame(timestamp_ms);
   EXPECT_THAT(source.sink_wants(), FpsGtResolutionEq(source.last_wants()));
   EXPECT_FALSE(stats_proxy_->GetStats().bw_limited_resolution);
   EXPECT_FALSE(stats_proxy_->GetStats().bw_limited_framerate);
   EXPECT_EQ(6, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest,
        FpsCountReturnsToZeroForFewerAdaptationsUpThanDownWithTwoResources) {
   const int kWidth = 1280;
   const int kHeight = 720;
   const int64_t kFrameIntervalMs = 150;
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);

   // Enable BALANCED preference, no initial limitation.
   AdaptingFrameForwarder source(&time_controller_);
   source.set_adaptation_enabled(true);
   video_stream_encoder_->SetSource(&source,
                                    webrtc::DegradationPreference::BALANCED);

   int64_t timestamp_ms = kFrameIntervalMs;
   source.IncomingCapturedFrame(CreateFrame(timestamp_ms, kWidth, kHeight));
   sink_.WaitForEncodedFrame(kWidth, kHeight);
   EXPECT_THAT(source.sink_wants(), FpsMaxResolutionMax());
   EXPECT_FALSE(stats_proxy_->GetStats().bw_limited_resolution);
   EXPECT_FALSE(stats_proxy_->GetStats().bw_limited_framerate);
   EXPECT_EQ(0, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   // Trigger adapt down, expect scaled down resolution (960x540@maxfps).
   video_stream_encoder_->TriggerQualityLow();
   timestamp_ms += kFrameIntervalMs;
   source.IncomingCapturedFrame(CreateFrame(timestamp_ms, kWidth, kHeight));
   sink_.WaitForEncodedFrame(timestamp_ms);
   EXPECT_THAT(source.sink_wants(),
               FpsMaxResolutionMatches(Lt(kWidth * kHeight)));
   EXPECT_TRUE(stats_proxy_->GetStats().bw_limited_resolution);
   EXPECT_FALSE(stats_proxy_->GetStats().bw_limited_framerate);
   EXPECT_EQ(1, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   // Trigger adapt down, expect scaled down resolution (640x360@maxfps).
   video_stream_encoder_->TriggerQualityLow();
   timestamp_ms += kFrameIntervalMs;
   source.IncomingCapturedFrame(CreateFrame(timestamp_ms, kWidth, kHeight));
   sink_.WaitForEncodedFrame(timestamp_ms);
   EXPECT_THAT(source.sink_wants(), FpsMaxResolutionLt(source.last_wants()));
   EXPECT_TRUE(stats_proxy_->GetStats().bw_limited_resolution);
   EXPECT_FALSE(stats_proxy_->GetStats().bw_limited_framerate);
   EXPECT_EQ(2, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   // Trigger adapt down, expect reduced fps (640x360@15fps).
   video_stream_encoder_->TriggerQualityLow();
   timestamp_ms += kFrameIntervalMs;
   source.IncomingCapturedFrame(CreateFrame(timestamp_ms, kWidth, kHeight));
   WaitForEncodedFrame(timestamp_ms);
   EXPECT_THAT(source.sink_wants(), FpsLtResolutionEq(source.last_wants()));
   EXPECT_TRUE(stats_proxy_->GetStats().bw_limited_resolution);
   EXPECT_TRUE(stats_proxy_->GetStats().bw_limited_framerate);
   EXPECT_EQ(3, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   // Source requests QVGA, expect reduced resolution (320x180@15fps).
   source.OnOutputFormatRequest(320, 180);
   timestamp_ms += kFrameIntervalMs;
   source.IncomingCapturedFrame(CreateFrame(timestamp_ms, kWidth, kHeight));
   WaitForEncodedFrame(320, 180);
   EXPECT_EQ(3, stats_proxy_->GetStats().number_of_quality_adapt_changes);
   EXPECT_EQ(0, stats_proxy_->GetStats().number_of_cpu_adapt_changes);

   // Trigger adapt down, expect reduced fps (320x180@7fps).
   video_stream_encoder_->TriggerCpuOveruse();
   timestamp_ms += kFrameIntervalMs;
   source.IncomingCapturedFrame(CreateFrame(timestamp_ms, kWidth, kHeight));
   WaitForEncodedFrame(timestamp_ms);
   EXPECT_THAT(source.sink_wants(), FpsLtResolutionEq(source.last_wants()));
   EXPECT_TRUE(stats_proxy_->GetStats().bw_limited_resolution);
   EXPECT_TRUE(stats_proxy_->GetStats().bw_limited_framerate);
   EXPECT_TRUE(stats_proxy_->GetStats().cpu_limited_resolution);
   EXPECT_TRUE(stats_proxy_->GetStats().cpu_limited_framerate);
   EXPECT_EQ(3, stats_proxy_->GetStats().number_of_quality_adapt_changes);
   EXPECT_EQ(1, stats_proxy_->GetStats().number_of_cpu_adapt_changes);

   // Source requests HD, expect increased resolution (640x360@7fps).
   source.OnOutputFormatRequest(1280, 720);
   timestamp_ms += kFrameIntervalMs;
   source.IncomingCapturedFrame(CreateFrame(timestamp_ms, kWidth, kHeight));
   WaitForEncodedFrame(timestamp_ms);
   EXPECT_EQ(3, stats_proxy_->GetStats().number_of_quality_adapt_changes);
   EXPECT_EQ(1, stats_proxy_->GetStats().number_of_cpu_adapt_changes);

   // Trigger adapt up, expect increased fps (640x360@(max-1)fps).
   video_stream_encoder_->TriggerCpuUnderuse();
   timestamp_ms += kFrameIntervalMs;
   source.IncomingCapturedFrame(CreateFrame(timestamp_ms, kWidth, kHeight));
   WaitForEncodedFrame(timestamp_ms);
   EXPECT_THAT(source.sink_wants(), FpsGtResolutionEq(source.last_wants()));
   EXPECT_TRUE(stats_proxy_->GetStats().bw_limited_resolution);
   EXPECT_TRUE(stats_proxy_->GetStats().bw_limited_framerate);
   EXPECT_TRUE(stats_proxy_->GetStats().cpu_limited_resolution);
   EXPECT_TRUE(stats_proxy_->GetStats().cpu_limited_framerate);
   EXPECT_EQ(3, stats_proxy_->GetStats().number_of_quality_adapt_changes);
   EXPECT_EQ(2, stats_proxy_->GetStats().number_of_cpu_adapt_changes);

   // Trigger adapt up, expect increased fps (640x360@maxfps).
   video_stream_encoder_->TriggerQualityHigh();
   video_stream_encoder_->TriggerCpuUnderuse();
   timestamp_ms += kFrameIntervalMs;
   source.IncomingCapturedFrame(CreateFrame(timestamp_ms, kWidth, kHeight));
   WaitForEncodedFrame(timestamp_ms);
   EXPECT_THAT(source.sink_wants(), FpsGtResolutionEq(source.last_wants()));
   EXPECT_TRUE(stats_proxy_->GetStats().bw_limited_resolution);
   EXPECT_FALSE(stats_proxy_->GetStats().bw_limited_framerate);
   EXPECT_TRUE(stats_proxy_->GetStats().cpu_limited_resolution);
   EXPECT_FALSE(stats_proxy_->GetStats().cpu_limited_framerate);
   EXPECT_EQ(4, stats_proxy_->GetStats().number_of_quality_adapt_changes);
   EXPECT_EQ(3, stats_proxy_->GetStats().number_of_cpu_adapt_changes);

   // Trigger adapt up, expect increased resolution (960x570@maxfps).
   video_stream_encoder_->TriggerQualityHigh();
   video_stream_encoder_->TriggerCpuUnderuse();
   timestamp_ms += kFrameIntervalMs;
   source.IncomingCapturedFrame(CreateFrame(timestamp_ms, kWidth, kHeight));
   WaitForEncodedFrame(timestamp_ms);
   EXPECT_THAT(source.sink_wants(), FpsEqResolutionGt(source.last_wants()));
   EXPECT_TRUE(stats_proxy_->GetStats().bw_limited_resolution);
   EXPECT_FALSE(stats_proxy_->GetStats().bw_limited_framerate);
   EXPECT_TRUE(stats_proxy_->GetStats().cpu_limited_resolution);
   EXPECT_FALSE(stats_proxy_->GetStats().cpu_limited_framerate);
   EXPECT_EQ(5, stats_proxy_->GetStats().number_of_quality_adapt_changes);
   EXPECT_EQ(4, stats_proxy_->GetStats().number_of_cpu_adapt_changes);

   // Trigger adapt up, expect increased resolution (1280x720@maxfps).
   video_stream_encoder_->TriggerQualityHigh();
   video_stream_encoder_->TriggerCpuUnderuse();
   timestamp_ms += kFrameIntervalMs;
   source.IncomingCapturedFrame(CreateFrame(timestamp_ms, kWidth, kHeight));
   WaitForEncodedFrame(timestamp_ms);
   EXPECT_THAT(source.sink_wants(), FpsEqResolutionGt(source.last_wants()));
   EXPECT_FALSE(stats_proxy_->GetStats().bw_limited_resolution);
   EXPECT_FALSE(stats_proxy_->GetStats().bw_limited_framerate);
   EXPECT_FALSE(stats_proxy_->GetStats().cpu_limited_resolution);
   EXPECT_FALSE(stats_proxy_->GetStats().cpu_limited_framerate);
   EXPECT_EQ(6, stats_proxy_->GetStats().number_of_quality_adapt_changes);
   EXPECT_EQ(5, stats_proxy_->GetStats().number_of_cpu_adapt_changes);

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest,
        NoChangeForInitialNormalUsage_MaintainFramerateMode) {
   const int kWidth = 1280;
   const int kHeight = 720;
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);

   // Enable MAINTAIN_FRAMERATE preference, no initial limitation.
   test::FrameForwarder source;
   video_stream_encoder_->SetSource(
       &source, webrtc::DegradationPreference::MAINTAIN_FRAMERATE);

   source.IncomingCapturedFrame(CreateFrame(1, kWidth, kHeight));
   WaitForEncodedFrame(kWidth, kHeight);
   EXPECT_THAT(source.sink_wants(), FpsMaxResolutionMax());
   EXPECT_FALSE(stats_proxy_->GetStats().cpu_limited_resolution);
   EXPECT_EQ(0, stats_proxy_->GetStats().number_of_cpu_adapt_changes);

   // Trigger adapt up, expect no change.
   video_stream_encoder_->TriggerCpuUnderuse();
   EXPECT_THAT(source.sink_wants(), FpsMaxResolutionMax());
   EXPECT_FALSE(stats_proxy_->GetStats().cpu_limited_resolution);
   EXPECT_EQ(0, stats_proxy_->GetStats().number_of_cpu_adapt_changes);

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest,
        NoChangeForInitialNormalUsage_MaintainResolutionMode) {
   const int kWidth = 1280;
   const int kHeight = 720;
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);

   // Enable MAINTAIN_RESOLUTION preference, no initial limitation.
   test::FrameForwarder source;
   video_stream_encoder_->SetSource(
       &source, webrtc::DegradationPreference::MAINTAIN_RESOLUTION);

   source.IncomingCapturedFrame(CreateFrame(1, kWidth, kHeight));
   WaitForEncodedFrame(kWidth, kHeight);
   EXPECT_THAT(source.sink_wants(), FpsMaxResolutionMax());
   EXPECT_FALSE(stats_proxy_->GetStats().cpu_limited_framerate);
   EXPECT_EQ(0, stats_proxy_->GetStats().number_of_cpu_adapt_changes);

   // Trigger adapt up, expect no change.
   video_stream_encoder_->TriggerCpuUnderuse();
   EXPECT_THAT(source.sink_wants(), FpsMaxResolutionMax());
   EXPECT_FALSE(stats_proxy_->GetStats().cpu_limited_framerate);
   EXPECT_EQ(0, stats_proxy_->GetStats().number_of_cpu_adapt_changes);

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest, NoChangeForInitialNormalUsage_BalancedMode) {
   const int kWidth = 1280;
   const int kHeight = 720;
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);

   // Enable BALANCED preference, no initial limitation.
   test::FrameForwarder source;
   video_stream_encoder_->SetSource(&source,
                                    webrtc::DegradationPreference::BALANCED);

   source.IncomingCapturedFrame(CreateFrame(1, kWidth, kHeight));
   sink_.WaitForEncodedFrame(kWidth, kHeight);
   EXPECT_THAT(source.sink_wants(), FpsMaxResolutionMax());
   EXPECT_FALSE(stats_proxy_->GetStats().bw_limited_resolution);
   EXPECT_FALSE(stats_proxy_->GetStats().cpu_limited_framerate);
   EXPECT_EQ(0, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   // Trigger adapt up, expect no change.
   video_stream_encoder_->TriggerQualityHigh();
   EXPECT_THAT(source.sink_wants(), FpsMaxResolutionMax());
   EXPECT_FALSE(stats_proxy_->GetStats().bw_limited_resolution);
   EXPECT_FALSE(stats_proxy_->GetStats().cpu_limited_framerate);
   EXPECT_EQ(0, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest, NoChangeForInitialNormalUsage_DisabledMode) {
   const int kWidth = 1280;
   const int kHeight = 720;
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);

   // Enable DISABLED preference, no initial limitation.
   test::FrameForwarder source;
   video_stream_encoder_->SetSource(&source,
                                    webrtc::DegradationPreference::DISABLED);

   source.IncomingCapturedFrame(CreateFrame(1, kWidth, kHeight));
   sink_.WaitForEncodedFrame(kWidth, kHeight);
   EXPECT_THAT(source.sink_wants(), FpsMaxResolutionMax());
   EXPECT_FALSE(stats_proxy_->GetStats().bw_limited_resolution);
   EXPECT_FALSE(stats_proxy_->GetStats().cpu_limited_framerate);
   EXPECT_EQ(0, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   // Trigger adapt up, expect no change.
   video_stream_encoder_->TriggerQualityHigh();
   EXPECT_THAT(source.sink_wants(), FpsMaxResolutionMax());
   EXPECT_FALSE(stats_proxy_->GetStats().bw_limited_resolution);
   EXPECT_FALSE(stats_proxy_->GetStats().cpu_limited_framerate);
   EXPECT_EQ(0, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest,
        AdaptsResolutionForLowQuality_MaintainFramerateMode) {
   const int kWidth = 1280;
   const int kHeight = 720;
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);

   // Enable MAINTAIN_FRAMERATE preference, no initial limitation.
   AdaptingFrameForwarder source(&time_controller_);
   source.set_adaptation_enabled(true);
   video_stream_encoder_->SetSource(
       &source, webrtc::DegradationPreference::MAINTAIN_FRAMERATE);

   source.IncomingCapturedFrame(CreateFrame(1, kWidth, kHeight));
   WaitForEncodedFrame(1);
   EXPECT_THAT(source.sink_wants(), FpsMaxResolutionMax());
   EXPECT_FALSE(stats_proxy_->GetStats().bw_limited_resolution);
   EXPECT_EQ(0, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   // Trigger adapt down, expect scaled down resolution.
   video_stream_encoder_->TriggerQualityLow();
   source.IncomingCapturedFrame(CreateFrame(2, kWidth, kHeight));
   WaitForEncodedFrame(2);
   EXPECT_THAT(source.sink_wants(),
               FpsMaxResolutionMatches(Lt(kWidth * kHeight)));
   EXPECT_TRUE(stats_proxy_->GetStats().bw_limited_resolution);
   EXPECT_EQ(1, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   // Trigger adapt up, expect no restriction.
   video_stream_encoder_->TriggerQualityHigh();
   EXPECT_THAT(source.sink_wants(), FpsMaxResolutionMax());
   EXPECT_FALSE(stats_proxy_->GetStats().bw_limited_resolution);
   EXPECT_EQ(2, stats_proxy_->GetStats().number_of_quality_adapt_changes);
   EXPECT_EQ(0, stats_proxy_->GetStats().number_of_cpu_adapt_changes);

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest,
        AdaptsFramerateForLowQuality_MaintainResolutionMode) {
   const int kWidth = 1280;
   const int kHeight = 720;
   const int kInputFps = 30;
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);

   VideoSendStream::Stats stats = stats_proxy_->GetStats();
   stats.input_frame_rate = kInputFps;
   stats_proxy_->SetMockStats(stats);

   // Expect no scaling to begin with (preference: MAINTAIN_FRAMERATE).
   video_source_.IncomingCapturedFrame(CreateFrame(1, kWidth, kHeight));
   sink_.WaitForEncodedFrame(1);
   EXPECT_THAT(video_source_.sink_wants(), FpsMaxResolutionMax());

   // Trigger adapt down, expect scaled down resolution.
   video_stream_encoder_->TriggerQualityLow();
   video_source_.IncomingCapturedFrame(CreateFrame(2, kWidth, kHeight));
   sink_.WaitForEncodedFrame(2);
   EXPECT_THAT(video_source_.sink_wants(),
               FpsMaxResolutionMatches(Lt(kWidth * kHeight)));

   // Enable MAINTAIN_RESOLUTION preference.
   test::FrameForwarder new_video_source;
   video_stream_encoder_->SetSourceAndWaitForRestrictionsUpdated(
       &new_video_source, webrtc::DegradationPreference::MAINTAIN_RESOLUTION);
   // Give the encoder queue time to process the change in degradation preference
   // by waiting for an encoded frame.
   new_video_source.IncomingCapturedFrame(CreateFrame(3, kWidth, kHeight));
   sink_.WaitForEncodedFrame(3);
   EXPECT_THAT(new_video_source.sink_wants(), FpsMaxResolutionMax());

   // Trigger adapt down, expect reduced framerate.
   video_stream_encoder_->TriggerQualityLow();
   new_video_source.IncomingCapturedFrame(CreateFrame(4, kWidth, kHeight));
   sink_.WaitForEncodedFrame(4);
   EXPECT_THAT(new_video_source.sink_wants(),
               FpsMatchesResolutionMax(Lt(kInputFps)));

   // Trigger adapt up, expect no restriction.
   video_stream_encoder_->TriggerQualityHigh();
   EXPECT_THAT(new_video_source.sink_wants(), FpsMaxResolutionMax());

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest, DoesNotScaleBelowSetResolutionLimit) {
   const int kWidth = 1280;
   const int kHeight = 720;
   const size_t kNumFrames = 10;

   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);

   // Enable adapter, expected input resolutions when downscaling:
   // 1280x720 -> 960x540 -> 640x360 -> 480x270 -> 320x180 (kMinPixelsPerFrame)
   video_source_.set_adaptation_enabled(true);

   EXPECT_FALSE(stats_proxy_->GetStats().bw_limited_resolution);
   EXPECT_EQ(0, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   int downscales = 0;
   for (size_t i = 1; i <= kNumFrames; i++) {
     video_source_.IncomingCapturedFrame(
         CreateFrame(i * kFrameIntervalMs, kWidth, kHeight));
     WaitForEncodedFrame(i * kFrameIntervalMs);

     // Trigger scale down.
     rtc::VideoSinkWants last_wants = video_source_.sink_wants();
     video_stream_encoder_->TriggerQualityLow();
     EXPECT_GE(video_source_.sink_wants().max_pixel_count, kMinPixelsPerFrame);

     if (video_source_.sink_wants().max_pixel_count < last_wants.max_pixel_count)
       ++downscales;

     EXPECT_TRUE(stats_proxy_->GetStats().bw_limited_resolution);
     EXPECT_EQ(downscales,
               stats_proxy_->GetStats().number_of_quality_adapt_changes);
     EXPECT_GT(downscales, 0);
   }
   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest,
        AdaptsResolutionUpAndDownTwiceOnOveruse_MaintainFramerateMode) {
   const int kWidth = 1280;
   const int kHeight = 720;
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);

   // Enable MAINTAIN_FRAMERATE preference, no initial limitation.
   AdaptingFrameForwarder source(&time_controller_);
   source.set_adaptation_enabled(true);
   video_stream_encoder_->SetSource(
       &source, webrtc::DegradationPreference::MAINTAIN_FRAMERATE);

   int64_t timestamp_ms = kFrameIntervalMs;
   source.IncomingCapturedFrame(CreateFrame(timestamp_ms, kWidth, kHeight));
   WaitForEncodedFrame(kWidth, kHeight);
   EXPECT_THAT(source.sink_wants(), FpsMaxResolutionMax());
   EXPECT_FALSE(stats_proxy_->GetStats().cpu_limited_resolution);
   EXPECT_EQ(0, stats_proxy_->GetStats().number_of_cpu_adapt_changes);

   // Trigger adapt down, expect scaled down resolution.
   video_stream_encoder_->TriggerCpuOveruse();
   timestamp_ms += kFrameIntervalMs;
   source.IncomingCapturedFrame(CreateFrame(timestamp_ms, kWidth, kHeight));
   WaitForEncodedFrame(timestamp_ms);
   EXPECT_THAT(source.sink_wants(),
               FpsMaxResolutionMatches(Lt(kWidth * kHeight)));
   EXPECT_TRUE(stats_proxy_->GetStats().cpu_limited_resolution);
   EXPECT_EQ(1, stats_proxy_->GetStats().number_of_cpu_adapt_changes);

   // Trigger adapt up, expect no restriction.
   video_stream_encoder_->TriggerCpuUnderuse();
   timestamp_ms += kFrameIntervalMs;
   source.IncomingCapturedFrame(CreateFrame(timestamp_ms, kWidth, kHeight));
   WaitForEncodedFrame(kWidth, kHeight);
   EXPECT_THAT(source.sink_wants(), FpsMaxResolutionMax());
   EXPECT_FALSE(stats_proxy_->GetStats().cpu_limited_resolution);
   EXPECT_EQ(2, stats_proxy_->GetStats().number_of_cpu_adapt_changes);

   // Trigger adapt down, expect scaled down resolution.
   video_stream_encoder_->TriggerCpuOveruse();
   timestamp_ms += kFrameIntervalMs;
   source.IncomingCapturedFrame(CreateFrame(timestamp_ms, kWidth, kHeight));
   WaitForEncodedFrame(timestamp_ms);
   EXPECT_THAT(source.sink_wants(),
               FpsMaxResolutionMatches(Lt(kWidth * kHeight)));
   EXPECT_TRUE(stats_proxy_->GetStats().cpu_limited_resolution);
   EXPECT_EQ(3, stats_proxy_->GetStats().number_of_cpu_adapt_changes);

   // Trigger adapt up, expect no restriction.
   video_stream_encoder_->TriggerCpuUnderuse();
   timestamp_ms += kFrameIntervalMs;
   source.IncomingCapturedFrame(CreateFrame(timestamp_ms, kWidth, kHeight));
   sink_.WaitForEncodedFrame(kWidth, kHeight);
   EXPECT_THAT(source.sink_wants(), FpsMaxResolutionMax());
   EXPECT_FALSE(stats_proxy_->GetStats().cpu_limited_resolution);
   EXPECT_EQ(4, stats_proxy_->GetStats().number_of_cpu_adapt_changes);

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest,
        AdaptsResolutionUpAndDownTwiceForLowQuality_BalancedMode_NoFpsLimit) {
   const int kWidth = 1280;
   const int kHeight = 720;
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);

   // Enable BALANCED preference, no initial limitation.
   AdaptingFrameForwarder source(&time_controller_);
   source.set_adaptation_enabled(true);
   video_stream_encoder_->SetSource(&source,
                                    webrtc::DegradationPreference::BALANCED);

   int64_t timestamp_ms = kFrameIntervalMs;
   source.IncomingCapturedFrame(CreateFrame(timestamp_ms, kWidth, kHeight));
   sink_.WaitForEncodedFrame(kWidth, kHeight);
   EXPECT_THAT(source.sink_wants(), FpsMaxResolutionMax());
   EXPECT_FALSE(stats_proxy_->GetStats().bw_limited_resolution);
   EXPECT_EQ(0, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   // Trigger adapt down, expect scaled down resolution.
   video_stream_encoder_->TriggerQualityLow();
   timestamp_ms += kFrameIntervalMs;
   source.IncomingCapturedFrame(CreateFrame(timestamp_ms, kWidth, kHeight));
   sink_.WaitForEncodedFrame(timestamp_ms);
   EXPECT_THAT(source.sink_wants(),
               FpsMaxResolutionMatches(Lt(kWidth * kHeight)));
   EXPECT_TRUE(stats_proxy_->GetStats().bw_limited_resolution);
   EXPECT_EQ(1, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   // Trigger adapt up, expect no restriction.
   video_stream_encoder_->TriggerQualityHigh();
   timestamp_ms += kFrameIntervalMs;
   source.IncomingCapturedFrame(CreateFrame(timestamp_ms, kWidth, kHeight));
   sink_.WaitForEncodedFrame(kWidth, kHeight);
   EXPECT_THAT(source.sink_wants(), FpsMaxResolutionMax());
   EXPECT_FALSE(stats_proxy_->GetStats().bw_limited_resolution);
   EXPECT_EQ(2, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   // Trigger adapt down, expect scaled down resolution.
   video_stream_encoder_->TriggerQualityLow();
   timestamp_ms += kFrameIntervalMs;
   source.IncomingCapturedFrame(CreateFrame(timestamp_ms, kWidth, kHeight));
   sink_.WaitForEncodedFrame(timestamp_ms);
   EXPECT_THAT(source.sink_wants(),
               FpsMaxResolutionMatches(Lt(kWidth * kHeight)));
   EXPECT_TRUE(stats_proxy_->GetStats().bw_limited_resolution);
   EXPECT_EQ(3, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   // Trigger adapt up, expect no restriction.
   video_stream_encoder_->TriggerQualityHigh();
   timestamp_ms += kFrameIntervalMs;
   source.IncomingCapturedFrame(CreateFrame(timestamp_ms, kWidth, kHeight));
   sink_.WaitForEncodedFrame(kWidth, kHeight);
   EXPECT_THAT(source.sink_wants(), FpsMaxResolutionMax());
   EXPECT_FALSE(stats_proxy_->GetStats().bw_limited_resolution);
   EXPECT_EQ(4, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest, AdaptUpIfBwEstimateIsHigherThanMinBitrate) {
   fake_encoder_.SetResolutionBitrateLimits(
       {kEncoderBitrateLimits540p, kEncoderBitrateLimits720p});

   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       DataRate::BitsPerSec(kEncoderBitrateLimits720p.min_start_bitrate_bps),
       DataRate::BitsPerSec(kEncoderBitrateLimits720p.min_start_bitrate_bps),
       DataRate::BitsPerSec(kEncoderBitrateLimits720p.min_start_bitrate_bps), 0,
       0, 0);

   // Enable MAINTAIN_FRAMERATE preference, no initial limitation.
   AdaptingFrameForwarder source(&time_controller_);
   source.set_adaptation_enabled(true);
   video_stream_encoder_->SetSource(
       &source, webrtc::DegradationPreference::MAINTAIN_FRAMERATE);

   // Insert 720p frame.
   int64_t timestamp_ms = kFrameIntervalMs;
   source.IncomingCapturedFrame(CreateFrame(timestamp_ms, 1280, 720));
   WaitForEncodedFrame(1280, 720);

   // Reduce bitrate and trigger adapt down.
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       DataRate::BitsPerSec(kEncoderBitrateLimits540p.min_start_bitrate_bps),
       DataRate::BitsPerSec(kEncoderBitrateLimits540p.min_start_bitrate_bps),
       DataRate::BitsPerSec(kEncoderBitrateLimits540p.min_start_bitrate_bps), 0,
       0, 0);
   video_stream_encoder_->TriggerQualityLow();

   // Insert 720p frame. It should be downscaled and encoded.
   timestamp_ms += kFrameIntervalMs;
   source.IncomingCapturedFrame(CreateFrame(timestamp_ms, 1280, 720));
   WaitForEncodedFrame(960, 540);

   // Trigger adapt up. Higher resolution should not be requested duo to lack
   // of bitrate.
   video_stream_encoder_->TriggerQualityHigh();
   EXPECT_THAT(source.sink_wants(), FpsMaxResolutionMatches(Lt(1280 * 720)));

   // Increase bitrate.
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       DataRate::BitsPerSec(kEncoderBitrateLimits720p.min_start_bitrate_bps),
       DataRate::BitsPerSec(kEncoderBitrateLimits720p.min_start_bitrate_bps),
       DataRate::BitsPerSec(kEncoderBitrateLimits720p.min_start_bitrate_bps), 0,
       0, 0);

   // Trigger adapt up. Higher resolution should be requested.
   video_stream_encoder_->TriggerQualityHigh();
   EXPECT_THAT(source.sink_wants(), FpsMaxResolutionMax());

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest, DropFirstFramesIfBwEstimateIsTooLow) {
   fake_encoder_.SetResolutionBitrateLimits(
       {kEncoderBitrateLimits540p, kEncoderBitrateLimits720p});

   // Set bitrate equal to min bitrate of 540p.
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       DataRate::BitsPerSec(kEncoderBitrateLimits540p.min_start_bitrate_bps),
       DataRate::BitsPerSec(kEncoderBitrateLimits540p.min_start_bitrate_bps),
       DataRate::BitsPerSec(kEncoderBitrateLimits540p.min_start_bitrate_bps), 0,
       0, 0);

   // Enable MAINTAIN_FRAMERATE preference, no initial limitation.
   AdaptingFrameForwarder source(&time_controller_);
   source.set_adaptation_enabled(true);
   video_stream_encoder_->SetSource(
       &source, webrtc::DegradationPreference::MAINTAIN_FRAMERATE);

   // Insert 720p frame. It should be dropped and lower resolution should be
   // requested.
   int64_t timestamp_ms = kFrameIntervalMs;
   source.IncomingCapturedFrame(CreateFrame(timestamp_ms, 1280, 720));
   ExpectDroppedFrame();
   EXPECT_TRUE_WAIT(source.sink_wants().max_pixel_count < 1280 * 720, 5000);

   // Insert 720p frame. It should be downscaled and encoded.
   timestamp_ms += kFrameIntervalMs;
   source.IncomingCapturedFrame(CreateFrame(timestamp_ms, 1280, 720));
   WaitForEncodedFrame(960, 540);

   video_stream_encoder_->Stop();
 }

 class BalancedDegradationTest : public VideoStreamEncoderTest {
  protected:
   void SetupTest() {
     // Reset encoder for field trials to take effect.
     ConfigureEncoder(video_encoder_config_.Copy());
     OnBitrateUpdated(kTargetBitrate);

     // Enable BALANCED preference.
     source_.set_adaptation_enabled(true);
     video_stream_encoder_->SetSource(&source_, DegradationPreference::BALANCED);
   }

   void OnBitrateUpdated(DataRate bitrate) {
     video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
         bitrate, bitrate, bitrate, 0, 0, 0);
   }

   void InsertFrame() {
     timestamp_ms_ += kFrameIntervalMs;
     source_.IncomingCapturedFrame(CreateFrame(timestamp_ms_, kWidth, kHeight));
   }

   void InsertFrameAndWaitForEncoded() {
     InsertFrame();
     sink_.WaitForEncodedFrame(timestamp_ms_);
   }

   const int kWidth = 640;  // pixels:640x360=230400
   const int kHeight = 360;
   const int64_t kFrameIntervalMs = 150;  // Use low fps to not drop any frame.
   int64_t timestamp_ms_ = 0;
   AdaptingFrameForwarder source_{&time_controller_};
 };

 TEST_F(BalancedDegradationTest, AdaptDownTwiceIfMinFpsDiffLtThreshold) {
   test::ScopedKeyValueConfig field_trials(
       field_trials_,
       "WebRTC-Video-BalancedDegradationSettings/"
       "pixels:57600|129600|230400,fps:7|10|24,fps_diff:1|1|1/");
   SetupTest();

   // Force input frame rate.
   const int kInputFps = 24;
   VideoSendStream::Stats stats = stats_proxy_->GetStats();
   stats.input_frame_rate = kInputFps;
   stats_proxy_->SetMockStats(stats);

   InsertFrameAndWaitForEncoded();
   EXPECT_THAT(source_.sink_wants(), FpsMaxResolutionMax());

   // Trigger adapt down, expect scaled down framerate and resolution,
   // since Fps diff (input-requested:0) < threshold.
   video_stream_encoder_->TriggerQualityLow();
   EXPECT_THAT(source_.sink_wants(),
               AllOf(WantsFps(Eq(24)), WantsMaxPixels(Le(230400))));

   video_stream_encoder_->Stop();
 }

 TEST_F(BalancedDegradationTest, AdaptDownOnceIfFpsDiffGeThreshold) {
   test::ScopedKeyValueConfig field_trials(
       field_trials_,
       "WebRTC-Video-BalancedDegradationSettings/"
       "pixels:57600|129600|230400,fps:7|10|24,fps_diff:1|1|1/");
   SetupTest();

   // Force input frame rate.
   const int kInputFps = 25;
   VideoSendStream::Stats stats = stats_proxy_->GetStats();
   stats.input_frame_rate = kInputFps;
   stats_proxy_->SetMockStats(stats);

   InsertFrameAndWaitForEncoded();
   EXPECT_THAT(source_.sink_wants(), FpsMaxResolutionMax());

   // Trigger adapt down, expect scaled down framerate only (640x360@24fps).
   // Fps diff (input-requested:1) == threshold.
   video_stream_encoder_->TriggerQualityLow();
   EXPECT_THAT(source_.sink_wants(), FpsMatchesResolutionMax(Eq(24)));

   video_stream_encoder_->Stop();
 }

 TEST_F(BalancedDegradationTest, AdaptDownUsesCodecSpecificFps) {
   test::ScopedKeyValueConfig field_trials(
       field_trials_,
       "WebRTC-Video-BalancedDegradationSettings/"
       "pixels:57600|129600|230400,fps:7|10|24,vp8_fps:8|11|22/");
   SetupTest();

   EXPECT_EQ(kVideoCodecVP8, video_encoder_config_.codec_type);

   InsertFrameAndWaitForEncoded();
   EXPECT_THAT(source_.sink_wants(), FpsMaxResolutionMax());

   // Trigger adapt down, expect scaled down framerate (640x360@22fps).
   video_stream_encoder_->TriggerQualityLow();
   EXPECT_THAT(source_.sink_wants(), FpsMatchesResolutionMax(Eq(22)));

   video_stream_encoder_->Stop();
 }

 TEST_F(BalancedDegradationTest, NoAdaptUpIfBwEstimateIsLessThanMinBitrate) {
   test::ScopedKeyValueConfig field_trials(
       field_trials_,
       "WebRTC-Video-BalancedDegradationSettings/"
       "pixels:57600|129600|230400,fps:7|10|14,kbps:0|0|425/");
   SetupTest();

   const DataRate kMinBitrate = DataRate::KilobitsPerSec(425);
   const DataRate kTooLowMinBitrate = DataRate::KilobitsPerSec(424);
   OnBitrateUpdated(kTooLowMinBitrate);

   InsertFrameAndWaitForEncoded();
   EXPECT_THAT(source_.sink_wants(), FpsMaxResolutionMax());
   EXPECT_EQ(0, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   // Trigger adapt down, expect scaled down framerate (640x360@14fps).
   video_stream_encoder_->TriggerQualityLow();
   InsertFrameAndWaitForEncoded();
   EXPECT_THAT(source_.sink_wants(), FpsMatchesResolutionMax(Eq(14)));
   EXPECT_EQ(1, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   // Trigger adapt down, expect scaled down resolution (480x270@14fps).
   video_stream_encoder_->TriggerQualityLow();
   InsertFrameAndWaitForEncoded();
   EXPECT_THAT(source_.sink_wants(), FpsEqResolutionLt(source_.last_wants()));
   EXPECT_EQ(2, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   // Trigger adapt down, expect scaled down framerate (480x270@10fps).
   video_stream_encoder_->TriggerQualityLow();
   InsertFrameAndWaitForEncoded();
   EXPECT_THAT(source_.sink_wants(), FpsLtResolutionEq(source_.last_wants()));
   EXPECT_EQ(source_.sink_wants().max_framerate_fps, 10);
   EXPECT_EQ(3, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   // Trigger adapt up, expect no upscale in fps (target bitrate < min bitrate).
   video_stream_encoder_->TriggerQualityHigh();
   InsertFrameAndWaitForEncoded();
   EXPECT_EQ(3, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   // Trigger adapt up, expect upscaled fps (target bitrate == min bitrate).
   OnBitrateUpdated(kMinBitrate);
   video_stream_encoder_->TriggerQualityHigh();
   InsertFrameAndWaitForEncoded();
   EXPECT_EQ(source_.sink_wants().max_framerate_fps, 14);
   EXPECT_EQ(4, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   video_stream_encoder_->Stop();
 }

 TEST_F(BalancedDegradationTest,
        InitialFrameDropAdaptsFpsAndResolutionInOneStep) {
   test::ScopedKeyValueConfig field_trials(
       field_trials_,
       "WebRTC-Video-BalancedDegradationSettings/"
       "pixels:57600|129600|230400,fps:7|24|24/");
   SetupTest();
   OnBitrateUpdated(kLowTargetBitrate);

   EXPECT_THAT(source_.sink_wants(), UnlimitedSinkWants());

   // Insert frame, expect scaled down:
   // framerate (640x360@24fps) -> resolution (480x270@24fps).
   InsertFrame();
   EXPECT_FALSE(WaitForFrame(TimeDelta::Seconds(1)));
   EXPECT_LT(source_.sink_wants().max_pixel_count, kWidth * kHeight);
   EXPECT_EQ(source_.sink_wants().max_framerate_fps, 24);

   // Insert frame, expect scaled down:
   // resolution (320x180@24fps).
   InsertFrame();
   EXPECT_FALSE(WaitForFrame(TimeDelta::Seconds(1)));
   EXPECT_LT(source_.sink_wants().max_pixel_count,
             source_.last_wants().max_pixel_count);
   EXPECT_EQ(source_.sink_wants().max_framerate_fps, 24);

   // Frame should not be dropped (min pixels per frame reached).
   InsertFrameAndWaitForEncoded();

   video_stream_encoder_->Stop();
 }

 TEST_F(BalancedDegradationTest,
        NoAdaptUpInResolutionIfBwEstimateIsLessThanMinBitrate) {
   test::ScopedKeyValueConfig field_trials(
       field_trials_,
       "WebRTC-Video-BalancedDegradationSettings/"
       "pixels:57600|129600|230400,fps:7|10|14,kbps_res:0|0|435/");
   SetupTest();

   const DataRate kResolutionMinBitrate = DataRate::KilobitsPerSec(435);
   const DataRate kTooLowMinResolutionBitrate = DataRate::KilobitsPerSec(434);
   OnBitrateUpdated(kTooLowMinResolutionBitrate);

   InsertFrameAndWaitForEncoded();
   EXPECT_THAT(source_.sink_wants(), FpsMaxResolutionMax());
   EXPECT_EQ(0, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   // Trigger adapt down, expect scaled down framerate (640x360@14fps).
   video_stream_encoder_->TriggerQualityLow();
   InsertFrameAndWaitForEncoded();
   EXPECT_THAT(source_.sink_wants(), FpsMatchesResolutionMax(Eq(14)));
   EXPECT_EQ(1, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   // Trigger adapt down, expect scaled down resolution (480x270@14fps).
   video_stream_encoder_->TriggerQualityLow();
   InsertFrameAndWaitForEncoded();
   EXPECT_THAT(source_.sink_wants(), FpsEqResolutionLt(source_.last_wants()));
   EXPECT_EQ(2, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   // Trigger adapt down, expect scaled down framerate (480x270@10fps).
   video_stream_encoder_->TriggerQualityLow();
   InsertFrameAndWaitForEncoded();
   EXPECT_THAT(source_.sink_wants(), FpsLtResolutionEq(source_.last_wants()));
   EXPECT_EQ(3, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   // Trigger adapt up, expect upscaled fps (no bitrate limit) (480x270@14fps).
   video_stream_encoder_->TriggerQualityHigh();
   InsertFrameAndWaitForEncoded();
   EXPECT_THAT(source_.sink_wants(), FpsGtResolutionEq(source_.last_wants()));
   EXPECT_EQ(4, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   // Trigger adapt up, expect no upscale in res (target bitrate < min bitrate).
   video_stream_encoder_->TriggerQualityHigh();
   InsertFrameAndWaitForEncoded();
   EXPECT_EQ(4, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   // Trigger adapt up, expect upscaled res (target bitrate == min bitrate).
   OnBitrateUpdated(kResolutionMinBitrate);
   video_stream_encoder_->TriggerQualityHigh();
   InsertFrameAndWaitForEncoded();
   EXPECT_THAT(source_.sink_wants(), FpsEqResolutionGt(source_.last_wants()));
   EXPECT_EQ(5, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   video_stream_encoder_->Stop();
 }

 TEST_F(BalancedDegradationTest,
        NoAdaptUpInFpsAndResolutionIfBwEstimateIsLessThanMinBitrate) {
   test::ScopedKeyValueConfig field_trials(
       field_trials_,
       "WebRTC-Video-BalancedDegradationSettings/"
       "pixels:57600|129600|230400,fps:7|10|14,kbps:0|0|425,kbps_res:0|0|435/");
   SetupTest();

   const DataRate kMinBitrate = DataRate::KilobitsPerSec(425);
   const DataRate kTooLowMinBitrate = DataRate::KilobitsPerSec(424);
   const DataRate kResolutionMinBitrate = DataRate::KilobitsPerSec(435);
   const DataRate kTooLowMinResolutionBitrate = DataRate::KilobitsPerSec(434);
   OnBitrateUpdated(kTooLowMinBitrate);

   InsertFrameAndWaitForEncoded();
   EXPECT_THAT(source_.sink_wants(), FpsMaxResolutionMax());
   EXPECT_EQ(0, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   // Trigger adapt down, expect scaled down framerate (640x360@14fps).
   video_stream_encoder_->TriggerQualityLow();
   InsertFrameAndWaitForEncoded();
   EXPECT_THAT(source_.sink_wants(), FpsMatchesResolutionMax(Eq(14)));
   EXPECT_EQ(1, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   // Trigger adapt down, expect scaled down resolution (480x270@14fps).
   video_stream_encoder_->TriggerQualityLow();
   InsertFrameAndWaitForEncoded();
   EXPECT_THAT(source_.sink_wants(), FpsEqResolutionLt(source_.last_wants()));
   EXPECT_EQ(2, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   // Trigger adapt down, expect scaled down framerate (480x270@10fps).
   video_stream_encoder_->TriggerQualityLow();
   InsertFrameAndWaitForEncoded();
   EXPECT_THAT(source_.sink_wants(), FpsLtResolutionEq(source_.last_wants()));
   EXPECT_EQ(3, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   // Trigger adapt up, expect no upscale (target bitrate < min bitrate).
   video_stream_encoder_->TriggerQualityHigh();
   InsertFrameAndWaitForEncoded();
   EXPECT_EQ(3, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   // Trigger adapt up, expect upscaled fps (target bitrate == min bitrate).
   OnBitrateUpdated(kMinBitrate);
   video_stream_encoder_->TriggerQualityHigh();
   InsertFrameAndWaitForEncoded();
   EXPECT_THAT(source_.sink_wants(), FpsGtResolutionEq(source_.last_wants()));
   EXPECT_EQ(4, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   // Trigger adapt up, expect no upscale in res (target bitrate < min bitrate).
   OnBitrateUpdated(kTooLowMinResolutionBitrate);
   video_stream_encoder_->TriggerQualityHigh();
   InsertFrameAndWaitForEncoded();
   EXPECT_EQ(4, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   // Trigger adapt up, expect upscaled res (target bitrate == min bitrate).
   OnBitrateUpdated(kResolutionMinBitrate);
   video_stream_encoder_->TriggerQualityHigh();
   InsertFrameAndWaitForEncoded();
   EXPECT_THAT(source_.sink_wants(), FpsEqResolutionGt(source_.last_wants()));
   EXPECT_EQ(5, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest,
        AdaptsResolutionOnOveruseAndLowQuality_MaintainFramerateMode) {
   const int kWidth = 1280;
   const int kHeight = 720;
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);

   // Enable MAINTAIN_FRAMERATE preference, no initial limitation.
   AdaptingFrameForwarder source(&time_controller_);
   source.set_adaptation_enabled(true);
   video_stream_encoder_->SetSource(
       &source, webrtc::DegradationPreference::MAINTAIN_FRAMERATE);

   int64_t timestamp_ms = kFrameIntervalMs;
   source.IncomingCapturedFrame(CreateFrame(timestamp_ms, kWidth, kHeight));
   WaitForEncodedFrame(kWidth, kHeight);
   EXPECT_THAT(source.sink_wants(), FpsMaxResolutionMax());
   EXPECT_FALSE(stats_proxy_->GetStats().cpu_limited_resolution);
   EXPECT_FALSE(stats_proxy_->GetStats().bw_limited_resolution);
   EXPECT_EQ(0, stats_proxy_->GetStats().number_of_cpu_adapt_changes);
   EXPECT_EQ(0, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   // Trigger cpu adapt down, expect scaled down resolution (960x540).
   video_stream_encoder_->TriggerCpuOveruse();
   timestamp_ms += kFrameIntervalMs;
   source.IncomingCapturedFrame(CreateFrame(timestamp_ms, kWidth, kHeight));
   WaitForEncodedFrame(timestamp_ms);
   EXPECT_THAT(source.sink_wants(),
               FpsMaxResolutionMatches(Lt(kWidth * kHeight)));
   EXPECT_TRUE(stats_proxy_->GetStats().cpu_limited_resolution);
   EXPECT_FALSE(stats_proxy_->GetStats().bw_limited_resolution);
   EXPECT_EQ(1, stats_proxy_->GetStats().number_of_cpu_adapt_changes);
   EXPECT_EQ(0, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   // Trigger cpu adapt down, expect scaled down resolution (640x360).
   video_stream_encoder_->TriggerCpuOveruse();
   timestamp_ms += kFrameIntervalMs;
   source.IncomingCapturedFrame(CreateFrame(timestamp_ms, kWidth, kHeight));
   WaitForEncodedFrame(timestamp_ms);
   EXPECT_THAT(source.sink_wants(), FpsMaxResolutionLt(source.last_wants()));
   EXPECT_TRUE(stats_proxy_->GetStats().cpu_limited_resolution);
   EXPECT_FALSE(stats_proxy_->GetStats().bw_limited_resolution);
   EXPECT_EQ(2, stats_proxy_->GetStats().number_of_cpu_adapt_changes);
   EXPECT_EQ(0, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   // Trigger cpu adapt down, expect scaled down resolution (480x270).
   video_stream_encoder_->TriggerCpuOveruse();
   timestamp_ms += kFrameIntervalMs;
   source.IncomingCapturedFrame(CreateFrame(timestamp_ms, kWidth, kHeight));
   WaitForEncodedFrame(timestamp_ms);
   EXPECT_THAT(source.sink_wants(), FpsMaxResolutionLt(source.last_wants()));
   EXPECT_TRUE(stats_proxy_->GetStats().cpu_limited_resolution);
   EXPECT_FALSE(stats_proxy_->GetStats().bw_limited_resolution);
   EXPECT_EQ(3, stats_proxy_->GetStats().number_of_cpu_adapt_changes);
   EXPECT_EQ(0, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   // Trigger quality adapt down, expect scaled down resolution (320x180).
   video_stream_encoder_->TriggerQualityLow();
   timestamp_ms += kFrameIntervalMs;
   source.IncomingCapturedFrame(CreateFrame(timestamp_ms, kWidth, kHeight));
   WaitForEncodedFrame(timestamp_ms);
   EXPECT_THAT(source.sink_wants(), FpsMaxResolutionLt(source.last_wants()));
   rtc::VideoSinkWants last_wants = source.sink_wants();
   EXPECT_TRUE(stats_proxy_->GetStats().cpu_limited_resolution);
   EXPECT_TRUE(stats_proxy_->GetStats().bw_limited_resolution);
   EXPECT_EQ(3, stats_proxy_->GetStats().number_of_cpu_adapt_changes);
   EXPECT_EQ(1, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   // Trigger quality adapt down, expect no change (min resolution reached).
   video_stream_encoder_->TriggerQualityLow();
   timestamp_ms += kFrameIntervalMs;
   source.IncomingCapturedFrame(CreateFrame(timestamp_ms, kWidth, kHeight));
   WaitForEncodedFrame(timestamp_ms);
   EXPECT_THAT(source.sink_wants(), FpsMax());
   EXPECT_EQ(source.sink_wants().max_pixel_count, last_wants.max_pixel_count);
   EXPECT_TRUE(stats_proxy_->GetStats().cpu_limited_resolution);
   EXPECT_TRUE(stats_proxy_->GetStats().bw_limited_resolution);
   EXPECT_EQ(3, stats_proxy_->GetStats().number_of_cpu_adapt_changes);
   EXPECT_EQ(1, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   // Trigger quality adapt up, expect upscaled resolution (480x270).
   video_stream_encoder_->TriggerQualityHigh();
   timestamp_ms += kFrameIntervalMs;
   source.IncomingCapturedFrame(CreateFrame(timestamp_ms, kWidth, kHeight));
   WaitForEncodedFrame(timestamp_ms);
   EXPECT_THAT(source.sink_wants(), FpsMaxResolutionGt(source.last_wants()));
   EXPECT_TRUE(stats_proxy_->GetStats().cpu_limited_resolution);
   EXPECT_TRUE(stats_proxy_->GetStats().bw_limited_resolution);
   EXPECT_EQ(3, stats_proxy_->GetStats().number_of_cpu_adapt_changes);
   EXPECT_EQ(2, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   // Trigger quality and cpu adapt up since both are most limited, expect
   // upscaled resolution (640x360).
   video_stream_encoder_->TriggerCpuUnderuse();
   video_stream_encoder_->TriggerQualityHigh();
   timestamp_ms += kFrameIntervalMs;
   source.IncomingCapturedFrame(CreateFrame(timestamp_ms, kWidth, kHeight));
   WaitForEncodedFrame(timestamp_ms);
   EXPECT_THAT(source.sink_wants(), FpsMaxResolutionGt(source.last_wants()));
   EXPECT_TRUE(stats_proxy_->GetStats().cpu_limited_resolution);
   EXPECT_TRUE(stats_proxy_->GetStats().bw_limited_resolution);
   EXPECT_EQ(4, stats_proxy_->GetStats().number_of_cpu_adapt_changes);
   EXPECT_EQ(3, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   // Trigger quality and cpu adapt up since both are most limited, expect
   // upscaled resolution (960x540).
   video_stream_encoder_->TriggerCpuUnderuse();
   video_stream_encoder_->TriggerQualityHigh();
   timestamp_ms += kFrameIntervalMs;
   source.IncomingCapturedFrame(CreateFrame(timestamp_ms, kWidth, kHeight));
   WaitForEncodedFrame(timestamp_ms);
   EXPECT_THAT(source.sink_wants(), FpsMaxResolutionGt(source.last_wants()));
   last_wants = source.sink_wants();
   EXPECT_TRUE(stats_proxy_->GetStats().cpu_limited_resolution);
   EXPECT_TRUE(stats_proxy_->GetStats().bw_limited_resolution);
   EXPECT_EQ(5, stats_proxy_->GetStats().number_of_cpu_adapt_changes);
   EXPECT_EQ(4, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   // Trigger cpu adapt up, expect no change since not most limited (960x540).
   // However the stats will change since the CPU resource is no longer limited.
   video_stream_encoder_->TriggerCpuUnderuse();
   timestamp_ms += kFrameIntervalMs;
   source.IncomingCapturedFrame(CreateFrame(timestamp_ms, kWidth, kHeight));
   WaitForEncodedFrame(timestamp_ms);
   EXPECT_THAT(source.sink_wants(), FpsEqResolutionEqTo(last_wants));
   EXPECT_FALSE(stats_proxy_->GetStats().cpu_limited_resolution);
   EXPECT_TRUE(stats_proxy_->GetStats().bw_limited_resolution);
   EXPECT_EQ(6, stats_proxy_->GetStats().number_of_cpu_adapt_changes);
   EXPECT_EQ(4, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   // Trigger quality adapt up, expect no restriction (1280x720).
   video_stream_encoder_->TriggerQualityHigh();
   timestamp_ms += kFrameIntervalMs;
   source.IncomingCapturedFrame(CreateFrame(timestamp_ms, kWidth, kHeight));
   WaitForEncodedFrame(kWidth, kHeight);
   EXPECT_THAT(source.sink_wants(), FpsMaxResolutionGt(source.last_wants()));
   EXPECT_THAT(source.sink_wants(), FpsMaxResolutionMax());
   EXPECT_FALSE(stats_proxy_->GetStats().cpu_limited_resolution);
   EXPECT_FALSE(stats_proxy_->GetStats().bw_limited_resolution);
   EXPECT_EQ(6, stats_proxy_->GetStats().number_of_cpu_adapt_changes);
   EXPECT_EQ(5, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest, CpuLimitedHistogramIsReported) {
   const int kWidth = 640;
   const int kHeight = 360;

   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);

   for (int i = 1; i <= SendStatisticsProxy::kMinRequiredMetricsSamples; ++i) {
     video_source_.IncomingCapturedFrame(CreateFrame(i, kWidth, kHeight));
     WaitForEncodedFrame(i);
   }

   video_stream_encoder_->TriggerCpuOveruse();
   for (int i = 1; i <= SendStatisticsProxy::kMinRequiredMetricsSamples; ++i) {
     video_source_.IncomingCapturedFrame(CreateFrame(
         SendStatisticsProxy::kMinRequiredMetricsSamples + i, kWidth, kHeight));
     WaitForEncodedFrame(SendStatisticsProxy::kMinRequiredMetricsSamples + i);
   }

   video_stream_encoder_->Stop();
   video_stream_encoder_.reset();
   stats_proxy_.reset();

   EXPECT_METRIC_EQ(
       1, metrics::NumSamples("WebRTC.Video.CpuLimitedResolutionInPercent"));
   EXPECT_METRIC_EQ(
       1, metrics::NumEvents("WebRTC.Video.CpuLimitedResolutionInPercent", 50));
 }

 TEST_F(VideoStreamEncoderTest,
        CpuLimitedHistogramIsNotReportedForDisabledDegradation) {
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);
   const int kWidth = 640;
   const int kHeight = 360;

   video_stream_encoder_->SetSource(&video_source_,
                                    webrtc::DegradationPreference::DISABLED);

   for (int i = 1; i <= SendStatisticsProxy::kMinRequiredMetricsSamples; ++i) {
     video_source_.IncomingCapturedFrame(CreateFrame(i, kWidth, kHeight));
     WaitForEncodedFrame(i);
   }

   video_stream_encoder_->Stop();
   video_stream_encoder_.reset();
   stats_proxy_.reset();

   EXPECT_EQ(0,
             metrics::NumSamples("WebRTC.Video.CpuLimitedResolutionInPercent"));
 }

 TEST_F(VideoStreamEncoderTest, ReportsVideoBitrateAllocation) {
   ResetEncoder("FAKE", 1, 1, 1, /*screenshare*/ false,
                VideoStreamEncoder::BitrateAllocationCallbackType::
                    kVideoBitrateAllocation);

   const int kDefaultFps = 30;
   const VideoBitrateAllocation expected_bitrate =
       SimulcastRateAllocator(fake_encoder_.config())
           .Allocate(VideoBitrateAllocationParameters(kLowTargetBitrate.bps(),
                                                      kDefaultFps));

   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kLowTargetBitrate, kLowTargetBitrate, kLowTargetBitrate, 0, 0, 0);

   video_source_.IncomingCapturedFrame(
       CreateFrame(CurrentTimeMs(), codec_width_, codec_height_));
   WaitForEncodedFrame(CurrentTimeMs());
   EXPECT_EQ(sink_.GetLastVideoBitrateAllocation(), expected_bitrate);
   EXPECT_EQ(sink_.number_of_bitrate_allocations(), 1);

   // Check that encoder has been updated too, not just allocation observer.
   EXPECT_TRUE(fake_encoder_.GetAndResetLastRateControlSettings().has_value());
   AdvanceTime(TimeDelta::Seconds(1) / kDefaultFps);

   // VideoBitrateAllocation not updated on second frame.
   video_source_.IncomingCapturedFrame(
       CreateFrame(CurrentTimeMs(), codec_width_, codec_height_));
   WaitForEncodedFrame(CurrentTimeMs());
   EXPECT_EQ(sink_.number_of_bitrate_allocations(), 1);
   AdvanceTime(TimeDelta::Millis(1) / kDefaultFps);

   // VideoBitrateAllocation updated after a process interval.
   const int64_t start_time_ms = CurrentTimeMs();
   while (CurrentTimeMs() - start_time_ms < 5 * kProcessIntervalMs) {
     video_source_.IncomingCapturedFrame(
         CreateFrame(CurrentTimeMs(), codec_width_, codec_height_));
     WaitForEncodedFrame(CurrentTimeMs());
     AdvanceTime(TimeDelta::Millis(1) / kDefaultFps);
   }
   EXPECT_GT(sink_.number_of_bitrate_allocations(), 3);

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest, ReportsVideoLayersAllocationForVP8Simulcast) {
   ResetEncoder("VP8", /*num_streams*/ 2, 1, 1, /*screenshare*/ false,
                VideoStreamEncoder::BitrateAllocationCallbackType::
                    kVideoLayersAllocation);

   const int kDefaultFps = 30;

   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kLowTargetBitrate, kLowTargetBitrate, kLowTargetBitrate, 0, 0, 0);

   video_source_.IncomingCapturedFrame(
       CreateFrame(CurrentTimeMs(), codec_width_, codec_height_));
   WaitForEncodedFrame(CurrentTimeMs());
   EXPECT_EQ(sink_.number_of_layers_allocations(), 1);
   VideoLayersAllocation last_layer_allocation =
       sink_.GetLastVideoLayersAllocation();
   // kLowTargetBitrate is only enough for one spatial layer.
   ASSERT_EQ(last_layer_allocation.active_spatial_layers.size(), 1u);

   VideoBitrateAllocation bitrate_allocation =
       fake_encoder_.GetAndResetLastRateControlSettings()->target_bitrate;
   // Check that encoder has been updated too, not just allocation observer.
   EXPECT_EQ(bitrate_allocation.get_sum_bps(), kLowTargetBitrate.bps());
   AdvanceTime(TimeDelta::Seconds(1) / kDefaultFps);

   // VideoLayersAllocation might be updated if frame rate changes.
   int number_of_layers_allocation = 1;
   const int64_t start_time_ms = CurrentTimeMs();
   while (CurrentTimeMs() - start_time_ms < 10 * kProcessIntervalMs) {
     video_source_.IncomingCapturedFrame(
         CreateFrame(CurrentTimeMs(), codec_width_, codec_height_));
     WaitForEncodedFrame(CurrentTimeMs());
     if (number_of_layers_allocation != sink_.number_of_layers_allocations()) {
       number_of_layers_allocation = sink_.number_of_layers_allocations();
       VideoLayersAllocation new_allocation =
           sink_.GetLastVideoLayersAllocation();
       ASSERT_EQ(new_allocation.active_spatial_layers.size(), 1u);
       EXPECT_NE(new_allocation.active_spatial_layers[0].frame_rate_fps,
                 last_layer_allocation.active_spatial_layers[0].frame_rate_fps);
       EXPECT_EQ(new_allocation.active_spatial_layers[0]
                     .target_bitrate_per_temporal_layer,
                 last_layer_allocation.active_spatial_layers[0]
                     .target_bitrate_per_temporal_layer);
       last_layer_allocation = new_allocation;
     }
   }
   EXPECT_LE(sink_.number_of_layers_allocations(), 3);
   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest,
        ReportsVideoLayersAllocationForVP8WithMiddleLayerDisabled) {
   fake_encoder_.SetTemporalLayersSupported(/*spatial_idx=*/0, true);
   fake_encoder_.SetTemporalLayersSupported(/*spatial_idx*/ 1, true);
   fake_encoder_.SetTemporalLayersSupported(/*spatial_idx*/ 2, true);
   VideoEncoderConfig video_encoder_config;
   test::FillEncoderConfiguration(VideoCodecType::kVideoCodecVP8,
                                  /* num_streams*/ 3, &video_encoder_config);
   video_encoder_config.max_bitrate_bps = 2 * kTargetBitrate.bps();
   video_encoder_config.content_type =
       VideoEncoderConfig::ContentType::kRealtimeVideo;
   video_encoder_config.encoder_specific_settings =
       rtc::make_ref_counted<VideoEncoderConfig::Vp8EncoderSpecificSettings>(
           VideoEncoder::GetDefaultVp8Settings());
   for (auto& layer : video_encoder_config.simulcast_layers) {
     layer.num_temporal_layers = 2;
   }
   // Simulcast layers are used for enabling/disabling streams.
   video_encoder_config.simulcast_layers[0].active = true;
   video_encoder_config.simulcast_layers[1].active = false;
   video_encoder_config.simulcast_layers[2].active = true;
   ConfigureEncoder(std::move(video_encoder_config),
                    VideoStreamEncoder::BitrateAllocationCallbackType::
                        kVideoLayersAllocation);

   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);

   video_source_.IncomingCapturedFrame(CreateFrame(CurrentTimeMs(), 1280, 720));
   WaitForEncodedFrame(CurrentTimeMs());
   EXPECT_EQ(sink_.number_of_layers_allocations(), 1);
   VideoLayersAllocation last_layer_allocation =
       sink_.GetLastVideoLayersAllocation();

   ASSERT_THAT(last_layer_allocation.active_spatial_layers, SizeIs(2));
   EXPECT_THAT(last_layer_allocation.active_spatial_layers[0]
                   .target_bitrate_per_temporal_layer,
               SizeIs(2));
   EXPECT_LT(last_layer_allocation.active_spatial_layers[0].width, 1280);
   EXPECT_EQ(last_layer_allocation.active_spatial_layers[1].width, 1280);
   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest,
        ReportsVideoLayersAllocationForVP8WithMiddleAndHighestLayerDisabled) {
   fake_encoder_.SetTemporalLayersSupported(/*spatial_idx=*/0, true);
   fake_encoder_.SetTemporalLayersSupported(/*spatial_idx*/ 1, true);
   fake_encoder_.SetTemporalLayersSupported(/*spatial_idx*/ 2, true);
   VideoEncoderConfig video_encoder_config;
   test::FillEncoderConfiguration(VideoCodecType::kVideoCodecVP8,
                                  /* num_streams*/ 3, &video_encoder_config);
   video_encoder_config.max_bitrate_bps = 2 * kTargetBitrate.bps();
   video_encoder_config.content_type =
       VideoEncoderConfig::ContentType::kRealtimeVideo;
   video_encoder_config.encoder_specific_settings =
       rtc::make_ref_counted<VideoEncoderConfig::Vp8EncoderSpecificSettings>(
           VideoEncoder::GetDefaultVp8Settings());
   for (auto& layer : video_encoder_config.simulcast_layers) {
     layer.num_temporal_layers = 2;
   }
   // Simulcast layers are used for enabling/disabling streams.
   video_encoder_config.simulcast_layers[0].active = true;
   video_encoder_config.simulcast_layers[1].active = false;
   video_encoder_config.simulcast_layers[2].active = false;
   ConfigureEncoder(std::move(video_encoder_config),
                    VideoStreamEncoder::BitrateAllocationCallbackType::
                        kVideoLayersAllocation);

   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);

   video_source_.IncomingCapturedFrame(CreateFrame(CurrentTimeMs(), 1280, 720));
   WaitForEncodedFrame(CurrentTimeMs());
   EXPECT_EQ(sink_.number_of_layers_allocations(), 1);
   VideoLayersAllocation last_layer_allocation =
       sink_.GetLastVideoLayersAllocation();

   ASSERT_THAT(last_layer_allocation.active_spatial_layers, SizeIs(1));
   EXPECT_THAT(last_layer_allocation.active_spatial_layers[0]
                   .target_bitrate_per_temporal_layer,
               SizeIs(2));
   EXPECT_LT(last_layer_allocation.active_spatial_layers[0].width, 1280);

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest,
        ReportsVideoLayersAllocationForV9SvcWithTemporalLayerSupport) {
   fake_encoder_.SetTemporalLayersSupported(/*spatial_idx=*/0, true);
   fake_encoder_.SetTemporalLayersSupported(/*spatial_idx*/ 1, true);
   VideoEncoderConfig video_encoder_config;
   test::FillEncoderConfiguration(VideoCodecType::kVideoCodecVP9,
                                  /* num_streams*/ 1, &video_encoder_config);
   video_encoder_config.max_bitrate_bps = 2 * kTargetBitrate.bps();
   video_encoder_config.content_type =
       VideoEncoderConfig::ContentType::kRealtimeVideo;
   VideoCodecVP9 vp9_settings = VideoEncoder::GetDefaultVp9Settings();
   vp9_settings.numberOfSpatialLayers = 2;
   vp9_settings.numberOfTemporalLayers = 2;
   vp9_settings.interLayerPred = InterLayerPredMode::kOn;
   vp9_settings.automaticResizeOn = false;
   video_encoder_config.encoder_specific_settings =
       rtc::make_ref_counted<VideoEncoderConfig::Vp9EncoderSpecificSettings>(
           vp9_settings);
   ConfigureEncoder(std::move(video_encoder_config),
                    VideoStreamEncoder::BitrateAllocationCallbackType::
                        kVideoLayersAllocation);

   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);

   video_source_.IncomingCapturedFrame(CreateFrame(CurrentTimeMs(), 1280, 720));
   WaitForEncodedFrame(CurrentTimeMs());
   EXPECT_EQ(sink_.number_of_layers_allocations(), 1);
   VideoLayersAllocation last_layer_allocation =
       sink_.GetLastVideoLayersAllocation();

   ASSERT_THAT(last_layer_allocation.active_spatial_layers, SizeIs(2));
   EXPECT_THAT(last_layer_allocation.active_spatial_layers[0]
                   .target_bitrate_per_temporal_layer,
               SizeIs(2));
   EXPECT_EQ(last_layer_allocation.active_spatial_layers[0].width, 640);
   EXPECT_EQ(last_layer_allocation.active_spatial_layers[0].height, 360);
   EXPECT_EQ(last_layer_allocation.active_spatial_layers[0].frame_rate_fps, 30);
   EXPECT_THAT(last_layer_allocation.active_spatial_layers[1]
                   .target_bitrate_per_temporal_layer,
               SizeIs(2));
   EXPECT_EQ(last_layer_allocation.active_spatial_layers[1].width, 1280);
   EXPECT_EQ(last_layer_allocation.active_spatial_layers[1].height, 720);
   EXPECT_EQ(last_layer_allocation.active_spatial_layers[1].frame_rate_fps, 30);

   // Since full SVC is used, expect the top layer to utilize the full target
   // rate.
   EXPECT_EQ(last_layer_allocation.active_spatial_layers[1]
                 .target_bitrate_per_temporal_layer[1],
             kTargetBitrate);
   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest,
        ReportsVideoLayersAllocationForV9SvcWithoutTemporalLayerSupport) {
   fake_encoder_.SetTemporalLayersSupported(/*spatial_idx=*/0, false);
   fake_encoder_.SetTemporalLayersSupported(/*spatial_idx*/ 1, false);
   VideoEncoderConfig video_encoder_config;
   test::FillEncoderConfiguration(VideoCodecType::kVideoCodecVP9,
                                  /* num_streams*/ 1, &video_encoder_config);
   video_encoder_config.max_bitrate_bps = 2 * kTargetBitrate.bps();
   video_encoder_config.content_type =
       VideoEncoderConfig::ContentType::kRealtimeVideo;
   VideoCodecVP9 vp9_settings = VideoEncoder::GetDefaultVp9Settings();
   vp9_settings.numberOfSpatialLayers = 2;
   vp9_settings.numberOfTemporalLayers = 2;
   vp9_settings.interLayerPred = InterLayerPredMode::kOn;
   vp9_settings.automaticResizeOn = false;
   video_encoder_config.encoder_specific_settings =
       rtc::make_ref_counted<VideoEncoderConfig::Vp9EncoderSpecificSettings>(
           vp9_settings);
   ConfigureEncoder(std::move(video_encoder_config),
                    VideoStreamEncoder::BitrateAllocationCallbackType::
                        kVideoLayersAllocation);

   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);

   video_source_.IncomingCapturedFrame(CreateFrame(CurrentTimeMs(), 1280, 720));
   WaitForEncodedFrame(CurrentTimeMs());
   EXPECT_EQ(sink_.number_of_layers_allocations(), 1);
   VideoLayersAllocation last_layer_allocation =
       sink_.GetLastVideoLayersAllocation();

   ASSERT_THAT(last_layer_allocation.active_spatial_layers, SizeIs(2));
   EXPECT_THAT(last_layer_allocation.active_spatial_layers[0]
                   .target_bitrate_per_temporal_layer,
               SizeIs(1));
   EXPECT_THAT(last_layer_allocation.active_spatial_layers[1]
                   .target_bitrate_per_temporal_layer,
               SizeIs(1));
   // Since full SVC is used, expect the top layer to utilize the full target
   // rate.
   EXPECT_EQ(last_layer_allocation.active_spatial_layers[1]
                 .target_bitrate_per_temporal_layer[0],
             kTargetBitrate);
   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest,
        ReportsVideoLayersAllocationForVP9KSvcWithTemporalLayerSupport) {
   fake_encoder_.SetTemporalLayersSupported(/*spatial_idx=*/0, true);
   fake_encoder_.SetTemporalLayersSupported(/*spatial_idx*/ 1, true);
   VideoEncoderConfig video_encoder_config;
   test::FillEncoderConfiguration(VideoCodecType::kVideoCodecVP9,
                                  /* num_streams*/ 1, &video_encoder_config);
   video_encoder_config.max_bitrate_bps = 2 * kTargetBitrate.bps();
   video_encoder_config.content_type =
       VideoEncoderConfig::ContentType::kRealtimeVideo;
   VideoCodecVP9 vp9_settings = VideoEncoder::GetDefaultVp9Settings();
   vp9_settings.numberOfSpatialLayers = 2;
   vp9_settings.numberOfTemporalLayers = 2;
   vp9_settings.interLayerPred = InterLayerPredMode::kOnKeyPic;
   vp9_settings.automaticResizeOn = false;
   video_encoder_config.encoder_specific_settings =
       rtc::make_ref_counted<VideoEncoderConfig::Vp9EncoderSpecificSettings>(
           vp9_settings);
   ConfigureEncoder(std::move(video_encoder_config),
                    VideoStreamEncoder::BitrateAllocationCallbackType::
                        kVideoLayersAllocation);

   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);

   video_source_.IncomingCapturedFrame(CreateFrame(CurrentTimeMs(), 1280, 720));
   WaitForEncodedFrame(CurrentTimeMs());
   EXPECT_EQ(sink_.number_of_layers_allocations(), 1);
   VideoLayersAllocation last_layer_allocation =
       sink_.GetLastVideoLayersAllocation();

   ASSERT_THAT(last_layer_allocation.active_spatial_layers, SizeIs(2));
   EXPECT_THAT(last_layer_allocation.active_spatial_layers[0]
                   .target_bitrate_per_temporal_layer,
               SizeIs(2));
   EXPECT_THAT(last_layer_allocation.active_spatial_layers[1]
                   .target_bitrate_per_temporal_layer,
               SizeIs(2));
   // Since  KSVC is, spatial layers are independend except on key frames.
   EXPECT_LT(last_layer_allocation.active_spatial_layers[1]
                 .target_bitrate_per_temporal_layer[1],
             kTargetBitrate);
   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest,
        ReportsVideoLayersAllocationForV9SvcWithLowestLayerDisabled) {
   fake_encoder_.SetTemporalLayersSupported(/*spatial_idx=*/0, true);
   fake_encoder_.SetTemporalLayersSupported(/*spatial_idx*/ 1, true);
   fake_encoder_.SetTemporalLayersSupported(/*spatial_idx*/ 2, true);
   VideoEncoderConfig video_encoder_config;
   test::FillEncoderConfiguration(VideoCodecType::kVideoCodecVP9,
                                  /* num_streams*/ 1, &video_encoder_config);
   video_encoder_config.max_bitrate_bps = 2 * kTargetBitrate.bps();
   video_encoder_config.content_type =
       VideoEncoderConfig::ContentType::kRealtimeVideo;
   VideoCodecVP9 vp9_settings = VideoEncoder::GetDefaultVp9Settings();
   vp9_settings.numberOfSpatialLayers = 3;
   vp9_settings.numberOfTemporalLayers = 2;
   vp9_settings.interLayerPred = InterLayerPredMode::kOn;
   vp9_settings.automaticResizeOn = false;
   video_encoder_config.encoder_specific_settings =
       rtc::make_ref_counted<VideoEncoderConfig::Vp9EncoderSpecificSettings>(
           vp9_settings);
   // Simulcast layers are used for enabling/disabling streams.
   video_encoder_config.simulcast_layers.resize(3);
   video_encoder_config.simulcast_layers[0].active = false;
   video_encoder_config.simulcast_layers[1].active = true;
   video_encoder_config.simulcast_layers[2].active = true;
   ConfigureEncoder(std::move(video_encoder_config),
                    VideoStreamEncoder::BitrateAllocationCallbackType::
                        kVideoLayersAllocation);

   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);

   video_source_.IncomingCapturedFrame(CreateFrame(CurrentTimeMs(), 1280, 720));
   WaitForEncodedFrame(CurrentTimeMs());
   EXPECT_EQ(sink_.number_of_layers_allocations(), 1);
   VideoLayersAllocation last_layer_allocation =
       sink_.GetLastVideoLayersAllocation();

   ASSERT_THAT(last_layer_allocation.active_spatial_layers, SizeIs(2));
   EXPECT_THAT(last_layer_allocation.active_spatial_layers[0]
                   .target_bitrate_per_temporal_layer,
               SizeIs(2));
   EXPECT_EQ(last_layer_allocation.active_spatial_layers[0].width, 640);
   EXPECT_EQ(last_layer_allocation.active_spatial_layers[0].spatial_id, 0);

   EXPECT_EQ(last_layer_allocation.active_spatial_layers[1].width, 1280);
   EXPECT_EQ(last_layer_allocation.active_spatial_layers[1].spatial_id, 1);
   EXPECT_THAT(last_layer_allocation.active_spatial_layers[1]
                   .target_bitrate_per_temporal_layer,
               SizeIs(2));
   // Since full SVC is used, expect the top layer to utilize the full target
   // rate.
   EXPECT_EQ(last_layer_allocation.active_spatial_layers[1]
                 .target_bitrate_per_temporal_layer[1],
             kTargetBitrate);
   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest,
        ReportsVideoLayersAllocationForV9SvcWithHighestLayerDisabled) {
   fake_encoder_.SetTemporalLayersSupported(/*spatial_idx=*/0, true);
   fake_encoder_.SetTemporalLayersSupported(/*spatial_idx*/ 1, true);
   fake_encoder_.SetTemporalLayersSupported(/*spatial_idx*/ 2, true);
   VideoEncoderConfig video_encoder_config;
   test::FillEncoderConfiguration(VideoCodecType::kVideoCodecVP9,
                                  /* num_streams*/ 1, &video_encoder_config);
   video_encoder_config.max_bitrate_bps = 2 * kTargetBitrate.bps();
   video_encoder_config.content_type =
       VideoEncoderConfig::ContentType::kRealtimeVideo;
   VideoCodecVP9 vp9_settings = VideoEncoder::GetDefaultVp9Settings();
   vp9_settings.numberOfSpatialLayers = 3;
   vp9_settings.numberOfTemporalLayers = 2;
   vp9_settings.interLayerPred = InterLayerPredMode::kOn;
   vp9_settings.automaticResizeOn = false;
   video_encoder_config.encoder_specific_settings =
       rtc::make_ref_counted<VideoEncoderConfig::Vp9EncoderSpecificSettings>(
           vp9_settings);
   // Simulcast layers are used for enabling/disabling streams.
   video_encoder_config.simulcast_layers.resize(3);
   video_encoder_config.simulcast_layers[2].active = false;
   ConfigureEncoder(std::move(video_encoder_config),
                    VideoStreamEncoder::BitrateAllocationCallbackType::
                        kVideoLayersAllocation);

   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);

   video_source_.IncomingCapturedFrame(CreateFrame(CurrentTimeMs(), 1280, 720));
   WaitForEncodedFrame(CurrentTimeMs());
   EXPECT_EQ(sink_.number_of_layers_allocations(), 1);
   VideoLayersAllocation last_layer_allocation =
       sink_.GetLastVideoLayersAllocation();

   ASSERT_THAT(last_layer_allocation.active_spatial_layers, SizeIs(2));
   EXPECT_THAT(last_layer_allocation.active_spatial_layers[0]
                   .target_bitrate_per_temporal_layer,
               SizeIs(2));
   EXPECT_EQ(last_layer_allocation.active_spatial_layers[0].width, 320);
   EXPECT_EQ(last_layer_allocation.active_spatial_layers[0].spatial_id, 0);

   EXPECT_EQ(last_layer_allocation.active_spatial_layers[1].width, 640);
   EXPECT_EQ(last_layer_allocation.active_spatial_layers[1].spatial_id, 1);
   EXPECT_THAT(last_layer_allocation.active_spatial_layers[1]
                   .target_bitrate_per_temporal_layer,
               SizeIs(2));
   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest,
        ReportsVideoLayersAllocationForV9SvcWithAllButHighestLayerDisabled) {
   fake_encoder_.SetTemporalLayersSupported(/*spatial_idx=*/0, true);
   fake_encoder_.SetTemporalLayersSupported(/*spatial_idx*/ 1, true);
   fake_encoder_.SetTemporalLayersSupported(/*spatial_idx*/ 2, true);
   VideoEncoderConfig video_encoder_config;
   test::FillEncoderConfiguration(VideoCodecType::kVideoCodecVP9,
                                  /* num_streams*/ 1, &video_encoder_config);
   video_encoder_config.max_bitrate_bps = 2 * kTargetBitrate.bps();
   video_encoder_config.content_type =
       VideoEncoderConfig::ContentType::kRealtimeVideo;
   VideoCodecVP9 vp9_settings = VideoEncoder::GetDefaultVp9Settings();
   vp9_settings.numberOfSpatialLayers = 3;
   vp9_settings.numberOfTemporalLayers = 2;
   vp9_settings.interLayerPred = InterLayerPredMode::kOn;
   vp9_settings.automaticResizeOn = false;
   video_encoder_config.encoder_specific_settings =
       rtc::make_ref_counted<VideoEncoderConfig::Vp9EncoderSpecificSettings>(
           vp9_settings);
   // Simulcast layers are used for enabling/disabling streams.
   video_encoder_config.simulcast_layers.resize(3);
   video_encoder_config.simulcast_layers[0].active = false;
   video_encoder_config.simulcast_layers[1].active = false;
   video_encoder_config.simulcast_layers[2].active = true;
   ConfigureEncoder(std::move(video_encoder_config),
                    VideoStreamEncoder::BitrateAllocationCallbackType::
                        kVideoLayersAllocation);

   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);

   video_source_.IncomingCapturedFrame(CreateFrame(CurrentTimeMs(), 1280, 720));
   WaitForEncodedFrame(CurrentTimeMs());
   EXPECT_EQ(sink_.number_of_layers_allocations(), 1);
   VideoLayersAllocation last_layer_allocation =
       sink_.GetLastVideoLayersAllocation();

   ASSERT_THAT(last_layer_allocation.active_spatial_layers, SizeIs(1));
   EXPECT_THAT(last_layer_allocation.active_spatial_layers[0]
                   .target_bitrate_per_temporal_layer,
               SizeIs(2));
   EXPECT_EQ(last_layer_allocation.active_spatial_layers[0].width, 1280);
   EXPECT_EQ(last_layer_allocation.active_spatial_layers[0].spatial_id, 0);
   EXPECT_EQ(last_layer_allocation.active_spatial_layers[0]
                 .target_bitrate_per_temporal_layer[1],
             kTargetBitrate);
   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest, ReportsVideoLayersAllocationForH264) {
   ResetEncoder("H264", 1, 1, 1, false,
                VideoStreamEncoder::BitrateAllocationCallbackType::
                    kVideoLayersAllocation);
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);

   video_source_.IncomingCapturedFrame(CreateFrame(CurrentTimeMs(), 1280, 720));
   WaitForEncodedFrame(CurrentTimeMs());
   EXPECT_EQ(sink_.number_of_layers_allocations(), 1);
   VideoLayersAllocation last_layer_allocation =
       sink_.GetLastVideoLayersAllocation();

   ASSERT_THAT(last_layer_allocation.active_spatial_layers, SizeIs(1));
   ASSERT_THAT(last_layer_allocation.active_spatial_layers[0]
                   .target_bitrate_per_temporal_layer,
               SizeIs(1));
   EXPECT_EQ(last_layer_allocation.active_spatial_layers[0]
                 .target_bitrate_per_temporal_layer[0],
             kTargetBitrate);
   EXPECT_EQ(last_layer_allocation.active_spatial_layers[0].width, 1280);
   EXPECT_EQ(last_layer_allocation.active_spatial_layers[0].height, 720);
   EXPECT_EQ(last_layer_allocation.active_spatial_layers[0].frame_rate_fps, 30);
   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest,
        ReportsUpdatedVideoLayersAllocationWhenBweChanges) {
   ResetEncoder("VP8", /*num_streams*/ 2, 1, 1, /*screenshare*/ false,
                VideoStreamEncoder::BitrateAllocationCallbackType::
                    kVideoLayersAllocation);

   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kLowTargetBitrate, kLowTargetBitrate, kLowTargetBitrate, 0, 0, 0);

   video_source_.IncomingCapturedFrame(
       CreateFrame(CurrentTimeMs(), codec_width_, codec_height_));
   WaitForEncodedFrame(CurrentTimeMs());
   EXPECT_EQ(sink_.number_of_layers_allocations(), 1);
   VideoLayersAllocation last_layer_allocation =
       sink_.GetLastVideoLayersAllocation();
   // kLowTargetBitrate is only enough for one spatial layer.
   ASSERT_EQ(last_layer_allocation.active_spatial_layers.size(), 1u);
   EXPECT_EQ(last_layer_allocation.active_spatial_layers[0]
                 .target_bitrate_per_temporal_layer[0],
             kLowTargetBitrate);

   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kSimulcastTargetBitrate, kSimulcastTargetBitrate, kSimulcastTargetBitrate,
       0, 0, 0);
   video_source_.IncomingCapturedFrame(
       CreateFrame(CurrentTimeMs(), codec_width_, codec_height_));
   WaitForEncodedFrame(CurrentTimeMs());

   EXPECT_EQ(sink_.number_of_layers_allocations(), 2);
   last_layer_allocation = sink_.GetLastVideoLayersAllocation();
   ASSERT_EQ(last_layer_allocation.active_spatial_layers.size(), 2u);
   EXPECT_GT(last_layer_allocation.active_spatial_layers[1]
                 .target_bitrate_per_temporal_layer[0],
             DataRate::Zero());

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest,
        ReportsUpdatedVideoLayersAllocationWhenResolutionChanges) {
   ResetEncoder("VP8", /*num_streams*/ 2, 1, 1, /*screenshare*/ false,
                VideoStreamEncoder::BitrateAllocationCallbackType::
                    kVideoLayersAllocation);

   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kSimulcastTargetBitrate, kSimulcastTargetBitrate, kSimulcastTargetBitrate,
       0, 0, 0);

   video_source_.IncomingCapturedFrame(
       CreateFrame(CurrentTimeMs(), codec_width_, codec_height_));
   WaitForEncodedFrame(CurrentTimeMs());
   EXPECT_EQ(sink_.number_of_layers_allocations(), 1);
   ASSERT_THAT(sink_.GetLastVideoLayersAllocation().active_spatial_layers,
               SizeIs(2));
   EXPECT_EQ(sink_.GetLastVideoLayersAllocation().active_spatial_layers[1].width,
             codec_width_);
   EXPECT_EQ(
       sink_.GetLastVideoLayersAllocation().active_spatial_layers[1].height,
       codec_height_);

   video_source_.IncomingCapturedFrame(
       CreateFrame(CurrentTimeMs(), codec_width_ / 2, codec_height_ / 2));
   WaitForEncodedFrame(CurrentTimeMs());
   EXPECT_EQ(sink_.number_of_layers_allocations(), 2);
   ASSERT_THAT(sink_.GetLastVideoLayersAllocation().active_spatial_layers,
               SizeIs(2));
   EXPECT_EQ(sink_.GetLastVideoLayersAllocation().active_spatial_layers[1].width,
             codec_width_ / 2);
   EXPECT_EQ(
       sink_.GetLastVideoLayersAllocation().active_spatial_layers[1].height,
       codec_height_ / 2);

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest, TemporalLayersNotDisabledIfSupported) {
   // 2 TLs configured, temporal layers supported by encoder.
   const int kNumTemporalLayers = 2;
   ResetEncoder("VP8", 1, kNumTemporalLayers, 1, /*screenshare*/ false,
                VideoStreamEncoder::BitrateAllocationCallbackType::
                    kVideoBitrateAllocation);
   fake_encoder_.SetTemporalLayersSupported(0, true);

   // Bitrate allocated across temporal layers.
   const int kTl0Bps = kTargetBitrate.bps() *
                       webrtc::SimulcastRateAllocator::GetTemporalRateAllocation(
                           kNumTemporalLayers, /*temporal_id*/ 0,
                           /*base_heavy_tl3_alloc*/ false);
   const int kTl1Bps = kTargetBitrate.bps() *
                       webrtc::SimulcastRateAllocator::GetTemporalRateAllocation(
                           kNumTemporalLayers, /*temporal_id*/ 1,
                           /*base_heavy_tl3_alloc*/ false);
   VideoBitrateAllocation expected_bitrate;
   expected_bitrate.SetBitrate(/*si*/ 0, /*ti*/ 0, kTl0Bps);
   expected_bitrate.SetBitrate(/*si*/ 0, /*ti*/ 1, kTl1Bps - kTl0Bps);

   VerifyAllocatedBitrate(expected_bitrate);
   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest, TemporalLayersDisabledIfNotSupported) {
   // 2 TLs configured, temporal layers not supported by encoder.
   ResetEncoder("VP8", 1, /*num_temporal_layers*/ 2, 1, /*screenshare*/ false,
                VideoStreamEncoder::BitrateAllocationCallbackType::
                    kVideoBitrateAllocation);
   fake_encoder_.SetTemporalLayersSupported(0, false);

   // Temporal layers not supported by the encoder.
   // Total bitrate should be at ti:0.
   VideoBitrateAllocation expected_bitrate;
   expected_bitrate.SetBitrate(/*si*/ 0, /*ti*/ 0, kTargetBitrate.bps());

   VerifyAllocatedBitrate(expected_bitrate);
   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest, VerifyBitrateAllocationForTwoStreams) {
   webrtc::test::ScopedKeyValueConfig field_trials(
       field_trials_,
       "WebRTC-Video-QualityScalerSettings/"
       "initial_bitrate_interval_ms:1000,initial_bitrate_factor:0.2/");
   // Reset encoder for field trials to take effect.
   ConfigureEncoder(video_encoder_config_.Copy());

   // 2 TLs configured, temporal layers only supported for first stream.
   ResetEncoder("VP8", 2, /*num_temporal_layers*/ 2, 1, /*screenshare*/ false,
                VideoStreamEncoder::BitrateAllocationCallbackType::
                    kVideoBitrateAllocation);
   fake_encoder_.SetTemporalLayersSupported(0, true);
   fake_encoder_.SetTemporalLayersSupported(1, false);

   const int kS0Bps = 150000;
   const int kS0Tl0Bps =
       kS0Bps *
       webrtc::SimulcastRateAllocator::GetTemporalRateAllocation(
           /*num_layers*/ 2, /*temporal_id*/ 0, /*base_heavy_tl3_alloc*/ false);
   const int kS0Tl1Bps =
       kS0Bps *
       webrtc::SimulcastRateAllocator::GetTemporalRateAllocation(
           /*num_layers*/ 2, /*temporal_id*/ 1, /*base_heavy_tl3_alloc*/ false);
   const int kS1Bps = kTargetBitrate.bps() - kS0Tl1Bps;
   // Temporal layers not supported by si:1.
   VideoBitrateAllocation expected_bitrate;
   expected_bitrate.SetBitrate(/*si*/ 0, /*ti*/ 0, kS0Tl0Bps);
   expected_bitrate.SetBitrate(/*si*/ 0, /*ti*/ 1, kS0Tl1Bps - kS0Tl0Bps);
   expected_bitrate.SetBitrate(/*si*/ 1, /*ti*/ 0, kS1Bps);

   VerifyAllocatedBitrate(expected_bitrate);
   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest, OveruseDetectorUpdatedOnReconfigureAndAdaption) {
   const int kFrameWidth = 1280;
   const int kFrameHeight = 720;
   const int kFramerate = 24;

   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);
   test::FrameForwarder source;
   video_stream_encoder_->SetSource(
       &source, webrtc::DegradationPreference::MAINTAIN_RESOLUTION);

   // Insert a single frame, triggering initial configuration.
   source.IncomingCapturedFrame(CreateFrame(1, kFrameWidth, kFrameHeight));
   video_stream_encoder_->WaitUntilTaskQueueIsIdle();

   EXPECT_EQ(
       video_stream_encoder_->overuse_detector_proxy_->GetLastTargetFramerate(),
       kDefaultFramerate);

   // Trigger reconfigure encoder (without resetting the entire instance).
   VideoEncoderConfig video_encoder_config;
   test::FillEncoderConfiguration(kVideoCodecVP8, 1, &video_encoder_config);
   video_encoder_config.simulcast_layers[0].max_framerate = kFramerate;
   video_encoder_config.max_bitrate_bps = kTargetBitrate.bps();
   video_stream_encoder_->ConfigureEncoder(std::move(video_encoder_config),
                                           kMaxPayloadLength);
   video_stream_encoder_->WaitUntilTaskQueueIsIdle();

   // Detector should be updated with fps limit from codec config.
   EXPECT_EQ(
       video_stream_encoder_->overuse_detector_proxy_->GetLastTargetFramerate(),
       kFramerate);

   // Trigger overuse, max framerate should be reduced.
   VideoSendStream::Stats stats = stats_proxy_->GetStats();
   stats.input_frame_rate = kFramerate;
   stats_proxy_->SetMockStats(stats);
   video_stream_encoder_->TriggerCpuOveruse();
   video_stream_encoder_->WaitUntilTaskQueueIsIdle();
   int adapted_framerate =
       video_stream_encoder_->overuse_detector_proxy_->GetLastTargetFramerate();
   EXPECT_LT(adapted_framerate, kFramerate);

   // Trigger underuse, max framerate should go back to codec configured fps.
   // Set extra low fps, to make sure it's actually reset, not just incremented.
   stats = stats_proxy_->GetStats();
   stats.input_frame_rate = adapted_framerate / 2;
   stats_proxy_->SetMockStats(stats);
   video_stream_encoder_->TriggerCpuUnderuse();
   video_stream_encoder_->WaitUntilTaskQueueIsIdle();
   EXPECT_EQ(
       video_stream_encoder_->overuse_detector_proxy_->GetLastTargetFramerate(),
       kFramerate);

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest,
        OveruseDetectorUpdatedRespectsFramerateAfterUnderuse) {
   const int kFrameWidth = 1280;
   const int kFrameHeight = 720;
   const int kLowFramerate = 15;
   const int kHighFramerate = 25;

   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);
   test::FrameForwarder source;
   video_stream_encoder_->SetSource(
       &source, webrtc::DegradationPreference::MAINTAIN_RESOLUTION);

   // Trigger initial configuration.
   VideoEncoderConfig video_encoder_config;
   test::FillEncoderConfiguration(kVideoCodecVP8, 1, &video_encoder_config);
   video_encoder_config.simulcast_layers[0].max_framerate = kLowFramerate;
   video_encoder_config.max_bitrate_bps = kTargetBitrate.bps();
   source.IncomingCapturedFrame(CreateFrame(1, kFrameWidth, kFrameHeight));
   video_stream_encoder_->ConfigureEncoder(video_encoder_config.Copy(),
                                           kMaxPayloadLength);
   video_stream_encoder_->WaitUntilTaskQueueIsIdle();

   EXPECT_EQ(
       video_stream_encoder_->overuse_detector_proxy_->GetLastTargetFramerate(),
       kLowFramerate);

   // Trigger overuse, max framerate should be reduced.
   VideoSendStream::Stats stats = stats_proxy_->GetStats();
   stats.input_frame_rate = kLowFramerate;
   stats_proxy_->SetMockStats(stats);
   video_stream_encoder_->TriggerCpuOveruse();
   video_stream_encoder_->WaitUntilTaskQueueIsIdle();
   int adapted_framerate =
       video_stream_encoder_->overuse_detector_proxy_->GetLastTargetFramerate();
   EXPECT_LT(adapted_framerate, kLowFramerate);

   // Reconfigure the encoder with a new (higher max framerate), max fps should
   // still respect the adaptation.
   video_encoder_config.simulcast_layers[0].max_framerate = kHighFramerate;
   source.IncomingCapturedFrame(CreateFrame(1, kFrameWidth, kFrameHeight));
   video_stream_encoder_->ConfigureEncoder(std::move(video_encoder_config),
                                           kMaxPayloadLength);
   video_stream_encoder_->WaitUntilTaskQueueIsIdle();

   EXPECT_EQ(
       video_stream_encoder_->overuse_detector_proxy_->GetLastTargetFramerate(),
       adapted_framerate);

   // Trigger underuse, max framerate should go back to codec configured fps.
   stats = stats_proxy_->GetStats();
   stats.input_frame_rate = adapted_framerate;
   stats_proxy_->SetMockStats(stats);
   video_stream_encoder_->TriggerCpuUnderuse();
   video_stream_encoder_->WaitUntilTaskQueueIsIdle();
   EXPECT_EQ(
       video_stream_encoder_->overuse_detector_proxy_->GetLastTargetFramerate(),
       kHighFramerate);

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest,
        OveruseDetectorUpdatedOnDegradationPreferenceChange) {
   const int kFrameWidth = 1280;
   const int kFrameHeight = 720;
   const int kFramerate = 24;

   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);
   test::FrameForwarder source;
   video_stream_encoder_->SetSource(
       &source, webrtc::DegradationPreference::MAINTAIN_RESOLUTION);

   // Trigger initial configuration.
   VideoEncoderConfig video_encoder_config;
   test::FillEncoderConfiguration(kVideoCodecVP8, 1, &video_encoder_config);
   video_encoder_config.simulcast_layers[0].max_framerate = kFramerate;
   video_encoder_config.max_bitrate_bps = kTargetBitrate.bps();
   source.IncomingCapturedFrame(CreateFrame(1, kFrameWidth, kFrameHeight));
   video_stream_encoder_->ConfigureEncoder(std::move(video_encoder_config),
                                           kMaxPayloadLength);
   video_stream_encoder_->WaitUntilTaskQueueIsIdle();

   EXPECT_EQ(
       video_stream_encoder_->overuse_detector_proxy_->GetLastTargetFramerate(),
       kFramerate);

   // Trigger overuse, max framerate should be reduced.
   VideoSendStream::Stats stats = stats_proxy_->GetStats();
   stats.input_frame_rate = kFramerate;
   stats_proxy_->SetMockStats(stats);
   video_stream_encoder_->TriggerCpuOveruse();
   video_stream_encoder_->WaitUntilTaskQueueIsIdle();
   int adapted_framerate =
       video_stream_encoder_->overuse_detector_proxy_->GetLastTargetFramerate();
   EXPECT_LT(adapted_framerate, kFramerate);

   // Change degradation preference to not enable framerate scaling. Target
   // framerate should be changed to codec defined limit.
   video_stream_encoder_->SetSourceAndWaitForFramerateUpdated(
       &source, webrtc::DegradationPreference::MAINTAIN_FRAMERATE);
   EXPECT_EQ(
       video_stream_encoder_->overuse_detector_proxy_->GetLastTargetFramerate(),
       kFramerate);

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest, DropsFramesAndScalesWhenBitrateIsTooLow) {
   const int kTooLowBitrateForFrameSizeBps = 10000;
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       DataRate::BitsPerSec(kTooLowBitrateForFrameSizeBps),
       DataRate::BitsPerSec(kTooLowBitrateForFrameSizeBps),
       DataRate::BitsPerSec(kTooLowBitrateForFrameSizeBps), 0, 0, 0);
   const int kWidth = 640;
   const int kHeight = 360;

   video_source_.IncomingCapturedFrame(CreateFrame(1, kWidth, kHeight));

   // Expect to drop this frame, the wait should time out.
   ExpectDroppedFrame();

   // Expect the sink_wants to specify a scaled frame.
   EXPECT_TRUE_WAIT(
       video_source_.sink_wants().max_pixel_count < kWidth * kHeight, 5000);

   int last_pixel_count = video_source_.sink_wants().max_pixel_count;

   // Next frame is scaled.
   video_source_.IncomingCapturedFrame(
       CreateFrame(2, kWidth * 3 / 4, kHeight * 3 / 4));

   // Expect to drop this frame, the wait should time out.
   ExpectDroppedFrame();

   EXPECT_TRUE_WAIT(
       video_source_.sink_wants().max_pixel_count < last_pixel_count, 5000);

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest,
        NumberOfDroppedFramesLimitedWhenBitrateIsTooLow) {
   const int kTooLowBitrateForFrameSizeBps = 10000;
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       DataRate::BitsPerSec(kTooLowBitrateForFrameSizeBps),
       DataRate::BitsPerSec(kTooLowBitrateForFrameSizeBps),
       DataRate::BitsPerSec(kTooLowBitrateForFrameSizeBps), 0, 0, 0);
   const int kWidth = 640;
   const int kHeight = 360;

   // We expect the n initial frames to get dropped.
   int i;
   for (i = 1; i <= kMaxInitialFramedrop; ++i) {
     video_source_.IncomingCapturedFrame(CreateFrame(i, kWidth, kHeight));
     ExpectDroppedFrame();
   }
   // The n+1th frame should not be dropped, even though it's size is too large.
   video_source_.IncomingCapturedFrame(CreateFrame(i, kWidth, kHeight));
   WaitForEncodedFrame(i);

   // Expect the sink_wants to specify a scaled frame.
   EXPECT_LT(video_source_.sink_wants().max_pixel_count, kWidth * kHeight);

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest,
        InitialFrameDropOffWithMaintainResolutionPreference) {
   const int kWidth = 640;
   const int kHeight = 360;
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kLowTargetBitrate, kLowTargetBitrate, kLowTargetBitrate, 0, 0, 0);

   // Set degradation preference.
   video_stream_encoder_->SetSource(
       &video_source_, webrtc::DegradationPreference::MAINTAIN_RESOLUTION);

   video_source_.IncomingCapturedFrame(CreateFrame(1, kWidth, kHeight));
   // Frame should not be dropped, even if it's too large.
   WaitForEncodedFrame(1);

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest, InitialFrameDropOffWhenEncoderDisabledScaling) {
   const int kWidth = 640;
   const int kHeight = 360;
   fake_encoder_.SetQualityScaling(false);

   VideoEncoderConfig video_encoder_config;
   test::FillEncoderConfiguration(kVideoCodecVP8, 1, &video_encoder_config);
   // Make format different, to force recreation of encoder.
   video_encoder_config.video_format.parameters["foo"] = "foo";
   video_stream_encoder_->ConfigureEncoder(std::move(video_encoder_config),
                                           kMaxPayloadLength);
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kLowTargetBitrate, kLowTargetBitrate, kLowTargetBitrate, 0, 0, 0);

   // Force quality scaler reconfiguration by resetting the source.
   video_stream_encoder_->SetSource(&video_source_,
                                    webrtc::DegradationPreference::BALANCED);

   video_source_.IncomingCapturedFrame(CreateFrame(1, kWidth, kHeight));
   // Frame should not be dropped, even if it's too large.
   WaitForEncodedFrame(1);

   video_stream_encoder_->Stop();
   fake_encoder_.SetQualityScaling(true);
 }

 TEST_F(VideoStreamEncoderTest, InitialFrameDropActivatesWhenBweDrops) {
   webrtc::test::ScopedKeyValueConfig field_trials(
       field_trials_,
       "WebRTC-Video-QualityScalerSettings/"
       "initial_bitrate_interval_ms:1000,initial_bitrate_factor:0.2/");
   // Reset encoder for field trials to take effect.
   ConfigureEncoder(video_encoder_config_.Copy());
   const int kNotTooLowBitrateForFrameSizeBps = kTargetBitrate.bps() * 0.2;
   const int kTooLowBitrateForFrameSizeBps = kTargetBitrate.bps() * 0.19;
   const int kWidth = 640;
   const int kHeight = 360;

   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);
   video_source_.IncomingCapturedFrame(CreateFrame(1, kWidth, kHeight));
   // Frame should not be dropped.
   WaitForEncodedFrame(1);

   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       DataRate::BitsPerSec(kNotTooLowBitrateForFrameSizeBps),
       DataRate::BitsPerSec(kNotTooLowBitrateForFrameSizeBps),
       DataRate::BitsPerSec(kNotTooLowBitrateForFrameSizeBps), 0, 0, 0);
   video_source_.IncomingCapturedFrame(CreateFrame(2, kWidth, kHeight));
   // Frame should not be dropped.
   WaitForEncodedFrame(2);

   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       DataRate::BitsPerSec(kTooLowBitrateForFrameSizeBps),
       DataRate::BitsPerSec(kTooLowBitrateForFrameSizeBps),
       DataRate::BitsPerSec(kTooLowBitrateForFrameSizeBps), 0, 0, 0);
   video_source_.IncomingCapturedFrame(CreateFrame(3, kWidth, kHeight));
   // Expect to drop this frame, the wait should time out.
   ExpectDroppedFrame();

   // Expect the sink_wants to specify a scaled frame.
   EXPECT_TRUE_WAIT(
       video_source_.sink_wants().max_pixel_count < kWidth * kHeight, 5000);
   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest,
        InitialFrameDropNotReactivatedWhenBweDropsWhenScalingDisabled) {
   webrtc::test::ScopedKeyValueConfig field_trials(
       field_trials_,
       "WebRTC-Video-QualityScalerSettings/"
       "initial_bitrate_interval_ms:1000,initial_bitrate_factor:0.2/");
   fake_encoder_.SetQualityScaling(false);
   ConfigureEncoder(video_encoder_config_.Copy());
   const int kNotTooLowBitrateForFrameSizeBps = kTargetBitrate.bps() * 0.2;
   const int kTooLowBitrateForFrameSizeBps = kTargetBitrate.bps() * 0.19;
   const int kWidth = 640;
   const int kHeight = 360;

   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);
   video_source_.IncomingCapturedFrame(CreateFrame(1, kWidth, kHeight));
   // Frame should not be dropped.
   WaitForEncodedFrame(1);

   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       DataRate::BitsPerSec(kNotTooLowBitrateForFrameSizeBps),
       DataRate::BitsPerSec(kNotTooLowBitrateForFrameSizeBps),
       DataRate::BitsPerSec(kNotTooLowBitrateForFrameSizeBps), 0, 0, 0);
   video_source_.IncomingCapturedFrame(CreateFrame(2, kWidth, kHeight));
   // Frame should not be dropped.
   WaitForEncodedFrame(2);

   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       DataRate::BitsPerSec(kTooLowBitrateForFrameSizeBps),
       DataRate::BitsPerSec(kTooLowBitrateForFrameSizeBps),
       DataRate::BitsPerSec(kTooLowBitrateForFrameSizeBps), 0, 0, 0);
   video_source_.IncomingCapturedFrame(CreateFrame(3, kWidth, kHeight));
   // Not dropped since quality scaling is disabled.
   WaitForEncodedFrame(3);

   // Expect the sink_wants to specify a scaled frame.
   video_stream_encoder_->WaitUntilTaskQueueIsIdle();
   EXPECT_THAT(video_source_.sink_wants(), ResolutionMax());

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest, InitialFrameDropAccountsForResolutionScaling) {
   VideoEncoderConfig video_encoder_config;
   webrtc::VideoEncoder::EncoderInfo encoder_info;
   test::FillEncoderConfiguration(PayloadStringToCodecType("VP8"), 1,
                                  &video_encoder_config);
   video_encoder_config.video_stream_factory =
       rtc::make_ref_counted<cricket::EncoderStreamFactory>(
           "VP8", /*max qp*/ 56, /*screencast*/ false,
           /*screenshare enabled*/ false, encoder_info);
   for (auto& layer : video_encoder_config.simulcast_layers) {
     layer.num_temporal_layers = 1;
     layer.max_framerate = kDefaultFramerate;
   }
   video_encoder_config.max_bitrate_bps = kSimulcastTargetBitrate.bps();
   video_encoder_config.content_type =
       VideoEncoderConfig::ContentType::kRealtimeVideo;

   video_encoder_config.simulcast_layers[0].active = true;
   video_encoder_config.simulcast_layers[0].scale_resolution_down_by = 4;

   video_stream_encoder_->ConfigureEncoder(video_encoder_config.Copy(),
                                           kMaxPayloadLength);
   video_stream_encoder_->WaitUntilTaskQueueIsIdle();

   // Bitrate is not enough for 720p.
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       DataRate::KilobitsPerSec(30), DataRate::KilobitsPerSec(30),
       DataRate::KilobitsPerSec(30), 0, 0, 0);

   // Pass 720p frame. Resolution scaling factor is set to 4 which means that
   // the target encode resolution is 180p. The default initial frame dropping
   // should not be active for 180p no matter of available bitrate.
   video_source_.IncomingCapturedFrame(CreateFrame(1, 1280, 720));
   WaitForEncodedFrame(1);

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest, InitialFrameDropActivatesWhenLayersChange) {
   const DataRate kLowTargetBitrate = DataRate::KilobitsPerSec(400);
   // Set simulcast.
   ResetEncoder("VP8", 3, 1, 1, false);
   fake_encoder_.SetQualityScaling(true);
   const int kWidth = 1280;
   const int kHeight = 720;
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kLowTargetBitrate, kLowTargetBitrate, kLowTargetBitrate, 0, 0, 0);
   video_source_.IncomingCapturedFrame(CreateFrame(1, kWidth, kHeight));
   // Frame should not be dropped.
   WaitForEncodedFrame(1);

   // Trigger QVGA "singlecast"
   // Update the config.
   VideoEncoderConfig video_encoder_config;
   webrtc::VideoEncoder::EncoderInfo encoder_info;
   test::FillEncoderConfiguration(PayloadStringToCodecType("VP8"), 3,
                                  &video_encoder_config);
   video_encoder_config.video_stream_factory =
       rtc::make_ref_counted<cricket::EncoderStreamFactory>(
           "VP8", /*max qp*/ 56, /*screencast*/ false,
           /*screenshare enabled*/ false, encoder_info);
   for (auto& layer : video_encoder_config.simulcast_layers) {
     layer.num_temporal_layers = 1;
     layer.max_framerate = kDefaultFramerate;
   }
   video_encoder_config.max_bitrate_bps = kSimulcastTargetBitrate.bps();
   video_encoder_config.content_type =
       VideoEncoderConfig::ContentType::kRealtimeVideo;

   video_encoder_config.simulcast_layers[0].active = true;
   video_encoder_config.simulcast_layers[1].active = false;
   video_encoder_config.simulcast_layers[2].active = false;

   video_stream_encoder_->ConfigureEncoder(video_encoder_config.Copy(),
                                           kMaxPayloadLength);
   video_stream_encoder_->WaitUntilTaskQueueIsIdle();

   video_source_.IncomingCapturedFrame(CreateFrame(2, kWidth, kHeight));
   // Frame should not be dropped.
   WaitForEncodedFrame(2);

   // Trigger HD "singlecast"
   video_encoder_config.simulcast_layers[0].active = false;
   video_encoder_config.simulcast_layers[1].active = false;
   video_encoder_config.simulcast_layers[2].active = true;

   video_stream_encoder_->ConfigureEncoder(video_encoder_config.Copy(),
                                           kMaxPayloadLength);
   video_stream_encoder_->WaitUntilTaskQueueIsIdle();

   video_source_.IncomingCapturedFrame(CreateFrame(3, kWidth, kHeight));
   // Frame should be dropped because of initial frame drop.
   ExpectDroppedFrame();

   // Expect the sink_wants to specify a scaled frame.
   EXPECT_TRUE_WAIT(
       video_source_.sink_wants().max_pixel_count < kWidth * kHeight, 5000);
   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest, InitialFrameDropActivatesWhenSVCLayersChange) {
   const DataRate kLowTargetBitrate = DataRate::KilobitsPerSec(400);
   // Set simulcast.
   ResetEncoder("VP9", 1, 1, 3, false);
   fake_encoder_.SetQualityScaling(true);
   const int kWidth = 1280;
   const int kHeight = 720;
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kLowTargetBitrate, kLowTargetBitrate, kLowTargetBitrate, 0, 0, 0);
   video_source_.IncomingCapturedFrame(CreateFrame(1, kWidth, kHeight));
   // Frame should not be dropped.
   WaitForEncodedFrame(1);

   // Trigger QVGA "singlecast"
   // Update the config.
   VideoEncoderConfig video_encoder_config;
   test::FillEncoderConfiguration(PayloadStringToCodecType("VP9"), 1,
                                  &video_encoder_config);
   VideoCodecVP9 vp9_settings = VideoEncoder::GetDefaultVp9Settings();
   vp9_settings.numberOfSpatialLayers = 3;
   // Since only one layer is active - automatic resize should be enabled.
   vp9_settings.automaticResizeOn = true;
   video_encoder_config.encoder_specific_settings =
       rtc::make_ref_counted<VideoEncoderConfig::Vp9EncoderSpecificSettings>(
           vp9_settings);
   video_encoder_config.max_bitrate_bps = kSimulcastTargetBitrate.bps();
   video_encoder_config.content_type =
       VideoEncoderConfig::ContentType::kRealtimeVideo;
   // Currently simulcast layers `active` flags are used to inidicate
   // which SVC layers are active.
   video_encoder_config.simulcast_layers.resize(3);

   video_encoder_config.simulcast_layers[0].active = true;
   video_encoder_config.simulcast_layers[1].active = false;
   video_encoder_config.simulcast_layers[2].active = false;

   video_stream_encoder_->ConfigureEncoder(video_encoder_config.Copy(),
                                           kMaxPayloadLength);
   video_stream_encoder_->WaitUntilTaskQueueIsIdle();

   video_source_.IncomingCapturedFrame(CreateFrame(2, kWidth, kHeight));
   // Frame should not be dropped.
   WaitForEncodedFrame(2);

   // Trigger HD "singlecast"
   video_encoder_config.simulcast_layers[0].active = false;
   video_encoder_config.simulcast_layers[1].active = false;
   video_encoder_config.simulcast_layers[2].active = true;

   video_stream_encoder_->ConfigureEncoder(video_encoder_config.Copy(),
                                           kMaxPayloadLength);
   video_stream_encoder_->WaitUntilTaskQueueIsIdle();

   video_source_.IncomingCapturedFrame(CreateFrame(3, kWidth, kHeight));
   // Frame should be dropped because of initial frame drop.
   ExpectDroppedFrame();

   // Expect the sink_wants to specify a scaled frame.
   EXPECT_TRUE_WAIT(
       video_source_.sink_wants().max_pixel_count < kWidth * kHeight, 5000);
   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest,
        EncoderMaxAndMinBitratesUsedIfMiddleStreamActive) {
   const VideoEncoder::ResolutionBitrateLimits kEncoderLimits270p(
       480 * 270, 34 * 1000, 12 * 1000, 1234 * 1000);
   const VideoEncoder::ResolutionBitrateLimits kEncoderLimits360p(
       640 * 360, 43 * 1000, 21 * 1000, 2345 * 1000);
   const VideoEncoder::ResolutionBitrateLimits kEncoderLimits720p(
       1280 * 720, 54 * 1000, 31 * 1000, 2500 * 1000);
   fake_encoder_.SetResolutionBitrateLimits(
       {kEncoderLimits270p, kEncoderLimits360p, kEncoderLimits720p});

   VideoEncoderConfig video_encoder_config;
   test::FillEncoderConfiguration(PayloadStringToCodecType("VP9"), 1,
                                  &video_encoder_config);
   VideoCodecVP9 vp9_settings = VideoEncoder::GetDefaultVp9Settings();
   vp9_settings.numberOfSpatialLayers = 3;
   // Since only one layer is active - automatic resize should be enabled.
   vp9_settings.automaticResizeOn = true;
   video_encoder_config.encoder_specific_settings =
       rtc::make_ref_counted<VideoEncoderConfig::Vp9EncoderSpecificSettings>(
           vp9_settings);
   video_encoder_config.max_bitrate_bps = kSimulcastTargetBitrate.bps();
   video_encoder_config.content_type =
       VideoEncoderConfig::ContentType::kRealtimeVideo;
   // Simulcast layers are used to indicate which spatial layers are active.
   video_encoder_config.simulcast_layers.resize(3);
   video_encoder_config.simulcast_layers[0].active = false;
   video_encoder_config.simulcast_layers[1].active = true;
   video_encoder_config.simulcast_layers[2].active = false;

   video_stream_encoder_->ConfigureEncoder(video_encoder_config.Copy(),
                                           kMaxPayloadLength);

   // The encoder bitrate limits for 360p should be used.
   video_source_.IncomingCapturedFrame(CreateFrame(1, 1280, 720));
   video_stream_encoder_->WaitUntilTaskQueueIsIdle();
   EXPECT_EQ(fake_encoder_.config().numberOfSimulcastStreams, 1);
   EXPECT_EQ(fake_encoder_.config().codecType, VideoCodecType::kVideoCodecVP9);
   EXPECT_EQ(fake_encoder_.config().VP9().numberOfSpatialLayers, 2);
   EXPECT_TRUE(fake_encoder_.config().spatialLayers[0].active);
   EXPECT_EQ(640, fake_encoder_.config().spatialLayers[0].width);
   EXPECT_EQ(360, fake_encoder_.config().spatialLayers[0].height);
   EXPECT_EQ(static_cast<uint32_t>(kEncoderLimits360p.min_bitrate_bps),
             fake_encoder_.config().spatialLayers[0].minBitrate * 1000);
   EXPECT_EQ(static_cast<uint32_t>(kEncoderLimits360p.max_bitrate_bps),
             fake_encoder_.config().spatialLayers[0].maxBitrate * 1000);

   // The encoder bitrate limits for 270p should be used.
   video_source_.IncomingCapturedFrame(CreateFrame(2, 960, 540));
   video_stream_encoder_->WaitUntilTaskQueueIsIdle();
   EXPECT_EQ(fake_encoder_.config().numberOfSimulcastStreams, 1);
   EXPECT_EQ(fake_encoder_.config().codecType, VideoCodecType::kVideoCodecVP9);
   EXPECT_EQ(fake_encoder_.config().VP9().numberOfSpatialLayers, 2);
   EXPECT_TRUE(fake_encoder_.config().spatialLayers[0].active);
   EXPECT_EQ(480, fake_encoder_.config().spatialLayers[0].width);
   EXPECT_EQ(270, fake_encoder_.config().spatialLayers[0].height);
   EXPECT_EQ(static_cast<uint32_t>(kEncoderLimits270p.min_bitrate_bps),
             fake_encoder_.config().spatialLayers[0].minBitrate * 1000);
   EXPECT_EQ(static_cast<uint32_t>(kEncoderLimits270p.max_bitrate_bps),
             fake_encoder_.config().spatialLayers[0].maxBitrate * 1000);

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest,
        DefaultMaxAndMinBitratesUsedIfMiddleStreamActive) {
   VideoEncoderConfig video_encoder_config;
   test::FillEncoderConfiguration(PayloadStringToCodecType("VP9"), 1,
                                  &video_encoder_config);
   VideoCodecVP9 vp9_settings = VideoEncoder::GetDefaultVp9Settings();
   vp9_settings.numberOfSpatialLayers = 3;
   // Since only one layer is active - automatic resize should be enabled.
   vp9_settings.automaticResizeOn = true;
   video_encoder_config.encoder_specific_settings =
       rtc::make_ref_counted<VideoEncoderConfig::Vp9EncoderSpecificSettings>(
           vp9_settings);
   video_encoder_config.max_bitrate_bps = kSimulcastTargetBitrate.bps();
   video_encoder_config.content_type =
       VideoEncoderConfig::ContentType::kRealtimeVideo;
   // Simulcast layers are used to indicate which spatial layers are active.
   video_encoder_config.simulcast_layers.resize(3);
   video_encoder_config.simulcast_layers[0].active = false;
   video_encoder_config.simulcast_layers[1].active = true;
   video_encoder_config.simulcast_layers[2].active = false;

   video_stream_encoder_->ConfigureEncoder(video_encoder_config.Copy(),
                                           kMaxPayloadLength);

   // The default bitrate limits for 360p should be used.
   const absl::optional<VideoEncoder::ResolutionBitrateLimits> kLimits360p =
       EncoderInfoSettings::GetDefaultSinglecastBitrateLimitsForResolution(
           kVideoCodecVP9, 640 * 360);
   video_source_.IncomingCapturedFrame(CreateFrame(1, 1280, 720));
   video_stream_encoder_->WaitUntilTaskQueueIsIdle();
   EXPECT_EQ(fake_encoder_.config().numberOfSimulcastStreams, 1);
   EXPECT_EQ(fake_encoder_.config().codecType, VideoCodecType::kVideoCodecVP9);
   EXPECT_EQ(fake_encoder_.config().VP9().numberOfSpatialLayers, 2);
   EXPECT_TRUE(fake_encoder_.config().spatialLayers[0].active);
   EXPECT_EQ(640, fake_encoder_.config().spatialLayers[0].width);
   EXPECT_EQ(360, fake_encoder_.config().spatialLayers[0].height);
   EXPECT_EQ(static_cast<uint32_t>(kLimits360p->min_bitrate_bps),
             fake_encoder_.config().spatialLayers[0].minBitrate * 1000);
   EXPECT_EQ(static_cast<uint32_t>(kLimits360p->max_bitrate_bps),
             fake_encoder_.config().spatialLayers[0].maxBitrate * 1000);

   // The default bitrate limits for 270p should be used.
   const absl::optional<VideoEncoder::ResolutionBitrateLimits> kLimits270p =
       EncoderInfoSettings::GetDefaultSinglecastBitrateLimitsForResolution(
           kVideoCodecVP9, 480 * 270);
   video_source_.IncomingCapturedFrame(CreateFrame(2, 960, 540));
   video_stream_encoder_->WaitUntilTaskQueueIsIdle();
   EXPECT_EQ(fake_encoder_.config().numberOfSimulcastStreams, 1);
   EXPECT_EQ(fake_encoder_.config().codecType, VideoCodecType::kVideoCodecVP9);
   EXPECT_EQ(fake_encoder_.config().VP9().numberOfSpatialLayers, 2);
   EXPECT_TRUE(fake_encoder_.config().spatialLayers[0].active);
   EXPECT_EQ(480, fake_encoder_.config().spatialLayers[0].width);
   EXPECT_EQ(270, fake_encoder_.config().spatialLayers[0].height);
   EXPECT_EQ(static_cast<uint32_t>(kLimits270p->min_bitrate_bps),
             fake_encoder_.config().spatialLayers[0].minBitrate * 1000);
   EXPECT_EQ(static_cast<uint32_t>(kLimits270p->max_bitrate_bps),
             fake_encoder_.config().spatialLayers[0].maxBitrate * 1000);

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest, DefaultMaxAndMinBitratesNotUsedIfDisabled) {
   webrtc::test::ScopedKeyValueConfig field_trials(
       field_trials_, "WebRTC-DefaultBitrateLimitsKillSwitch/Enabled/");
   VideoEncoderConfig video_encoder_config;
   test::FillEncoderConfiguration(PayloadStringToCodecType("VP9"), 1,
                                  &video_encoder_config);
   VideoCodecVP9 vp9_settings = VideoEncoder::GetDefaultVp9Settings();
   vp9_settings.numberOfSpatialLayers = 3;
   // Since only one layer is active - automatic resize should be enabled.
   vp9_settings.automaticResizeOn = true;
   video_encoder_config.encoder_specific_settings =
       rtc::make_ref_counted<VideoEncoderConfig::Vp9EncoderSpecificSettings>(
           vp9_settings);
   video_encoder_config.max_bitrate_bps = kSimulcastTargetBitrate.bps();
   video_encoder_config.content_type =
       VideoEncoderConfig::ContentType::kRealtimeVideo;
   // Simulcast layers are used to indicate which spatial layers are active.
   video_encoder_config.simulcast_layers.resize(3);
   video_encoder_config.simulcast_layers[0].active = false;
   video_encoder_config.simulcast_layers[1].active = true;
   video_encoder_config.simulcast_layers[2].active = false;

   // Reset encoder for field trials to take effect.
   ConfigureEncoder(video_encoder_config.Copy());

   video_stream_encoder_->ConfigureEncoder(video_encoder_config.Copy(),
                                           kMaxPayloadLength);

   // The default bitrate limits for 360p should not be used.
   const absl::optional<VideoEncoder::ResolutionBitrateLimits> kLimits360p =
       EncoderInfoSettings::GetDefaultSinglecastBitrateLimitsForResolution(
           kVideoCodecVP9, 640 * 360);
   video_source_.IncomingCapturedFrame(CreateFrame(1, 1280, 720));
   video_stream_encoder_->WaitUntilTaskQueueIsIdle();
   EXPECT_EQ(fake_encoder_.config().numberOfSimulcastStreams, 1);
   EXPECT_EQ(fake_encoder_.config().codecType, kVideoCodecVP9);
   EXPECT_EQ(fake_encoder_.config().VP9().numberOfSpatialLayers, 2);
   EXPECT_TRUE(fake_encoder_.config().spatialLayers[0].active);
   EXPECT_EQ(640, fake_encoder_.config().spatialLayers[0].width);
   EXPECT_EQ(360, fake_encoder_.config().spatialLayers[0].height);
   EXPECT_NE(static_cast<uint32_t>(kLimits360p->max_bitrate_bps),
             fake_encoder_.config().spatialLayers[0].maxBitrate * 1000);

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest, SinglecastBitrateLimitsNotUsedForOneStream) {
   ResetEncoder("VP9", /*num_streams=*/1, /*num_temporal_layers=*/1,
                /*num_spatial_layers=*/1, /*screenshare=*/false);

   // The default singlecast bitrate limits for 720p should not be used.
   const absl::optional<VideoEncoder::ResolutionBitrateLimits> kLimits720p =
       EncoderInfoSettings::GetDefaultSinglecastBitrateLimitsForResolution(
           kVideoCodecVP9, 1280 * 720);
   video_source_.IncomingCapturedFrame(CreateFrame(1, 1280, 720));
   video_stream_encoder_->WaitUntilTaskQueueIsIdle();
   EXPECT_EQ(fake_encoder_.config().numberOfSimulcastStreams, 1);
   EXPECT_EQ(fake_encoder_.config().codecType, VideoCodecType::kVideoCodecVP9);
   EXPECT_EQ(fake_encoder_.config().VP9().numberOfSpatialLayers, 1);
   EXPECT_TRUE(fake_encoder_.config().spatialLayers[0].active);
   EXPECT_EQ(1280, fake_encoder_.config().spatialLayers[0].width);
   EXPECT_EQ(720, fake_encoder_.config().spatialLayers[0].height);
   EXPECT_NE(static_cast<uint32_t>(kLimits720p->max_bitrate_bps),
             fake_encoder_.config().spatialLayers[0].maxBitrate * 1000);

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest,
        EncoderMaxAndMinBitratesNotUsedIfLowestStreamActive) {
   const VideoEncoder::ResolutionBitrateLimits kEncoderLimits180p(
       320 * 180, 34 * 1000, 12 * 1000, 1234 * 1000);
   const VideoEncoder::ResolutionBitrateLimits kEncoderLimits720p(
       1280 * 720, 54 * 1000, 31 * 1000, 2500 * 1000);
   fake_encoder_.SetResolutionBitrateLimits(
       {kEncoderLimits180p, kEncoderLimits720p});

   VideoEncoderConfig video_encoder_config;
   test::FillEncoderConfiguration(PayloadStringToCodecType("VP9"), 1,
                                  &video_encoder_config);
   VideoCodecVP9 vp9_settings = VideoEncoder::GetDefaultVp9Settings();
   vp9_settings.numberOfSpatialLayers = 3;
   // Since only one layer is active - automatic resize should be enabled.
   vp9_settings.automaticResizeOn = true;
   video_encoder_config.encoder_specific_settings =
       rtc::make_ref_counted<VideoEncoderConfig::Vp9EncoderSpecificSettings>(
           vp9_settings);
   video_encoder_config.max_bitrate_bps = kSimulcastTargetBitrate.bps();
   video_encoder_config.content_type =
       VideoEncoderConfig::ContentType::kRealtimeVideo;
   // Simulcast layers are used to indicate which spatial layers are active.
   video_encoder_config.simulcast_layers.resize(3);
   video_encoder_config.simulcast_layers[0].active = true;
   video_encoder_config.simulcast_layers[1].active = false;
   video_encoder_config.simulcast_layers[2].active = false;

   video_stream_encoder_->ConfigureEncoder(video_encoder_config.Copy(),
                                           kMaxPayloadLength);

   // Limits not applied on lowest stream, limits for 180p should not be used.
   video_source_.IncomingCapturedFrame(CreateFrame(1, 1280, 720));
   video_stream_encoder_->WaitUntilTaskQueueIsIdle();
   EXPECT_EQ(fake_encoder_.config().numberOfSimulcastStreams, 1);
   EXPECT_EQ(fake_encoder_.config().codecType, VideoCodecType::kVideoCodecVP9);
   EXPECT_EQ(fake_encoder_.config().VP9().numberOfSpatialLayers, 3);
   EXPECT_TRUE(fake_encoder_.config().spatialLayers[0].active);
   EXPECT_EQ(320, fake_encoder_.config().spatialLayers[0].width);
   EXPECT_EQ(180, fake_encoder_.config().spatialLayers[0].height);
   EXPECT_NE(static_cast<uint32_t>(kEncoderLimits180p.min_bitrate_bps),
             fake_encoder_.config().spatialLayers[0].minBitrate * 1000);
   EXPECT_NE(static_cast<uint32_t>(kEncoderLimits180p.max_bitrate_bps),
             fake_encoder_.config().spatialLayers[0].maxBitrate * 1000);

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest,
        InitialFrameDropActivatesWhenResolutionIncreases) {
   const int kWidth = 640;
   const int kHeight = 360;

   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);
   video_source_.IncomingCapturedFrame(CreateFrame(1, kWidth / 2, kHeight / 2));
   // Frame should not be dropped.
   WaitForEncodedFrame(1);

   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kLowTargetBitrate, kLowTargetBitrate, kLowTargetBitrate, 0, 0, 0);
   video_source_.IncomingCapturedFrame(CreateFrame(2, kWidth / 2, kHeight / 2));
   // Frame should not be dropped, bitrate not too low for frame.
   WaitForEncodedFrame(2);

   // Incoming resolution increases.
   video_source_.IncomingCapturedFrame(CreateFrame(3, kWidth, kHeight));
   // Expect to drop this frame, bitrate too low for frame.
   ExpectDroppedFrame();

   // Expect the sink_wants to specify a scaled frame.
   EXPECT_TRUE_WAIT(
       video_source_.sink_wants().max_pixel_count < kWidth * kHeight, 5000);
   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest, InitialFrameDropIsNotReactivatedWhenAdaptingUp) {
   const int kWidth = 640;
   const int kHeight = 360;
   // So that quality scaling doesn't happen by itself.
   fake_encoder_.SetQp(kQpHigh);

   AdaptingFrameForwarder source(&time_controller_);
   source.set_adaptation_enabled(true);
   video_stream_encoder_->SetSource(
       &source, webrtc::DegradationPreference::MAINTAIN_FRAMERATE);

   int timestamp = 1;

   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);
   source.IncomingCapturedFrame(CreateFrame(timestamp, kWidth, kHeight));
   WaitForEncodedFrame(timestamp);
   timestamp += 9000;
   // Long pause to disable all first BWE drop logic.
   AdvanceTime(TimeDelta::Millis(1000));

   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kLowTargetBitrate, kLowTargetBitrate, kLowTargetBitrate, 0, 0, 0);
   source.IncomingCapturedFrame(CreateFrame(timestamp, kWidth, kHeight));
   // Not dropped frame, as initial frame drop is disabled by now.
   WaitForEncodedFrame(timestamp);
   timestamp += 9000;
   AdvanceTime(TimeDelta::Millis(100));

   // Quality adaptation down.
   video_stream_encoder_->TriggerQualityLow();

   // Adaptation has an effect.
   EXPECT_TRUE_WAIT(source.sink_wants().max_pixel_count < kWidth * kHeight,
                    5000);

   // Frame isn't dropped as initial frame dropper is disabled.
   source.IncomingCapturedFrame(CreateFrame(timestamp, kWidth, kHeight));
   WaitForEncodedFrame(timestamp);
   timestamp += 9000;
   AdvanceTime(TimeDelta::Millis(100));

   // Quality adaptation up.
   video_stream_encoder_->TriggerQualityHigh();

   // Adaptation has an effect.
   EXPECT_TRUE_WAIT(source.sink_wants().max_pixel_count > kWidth * kHeight,
                    5000);

   source.IncomingCapturedFrame(CreateFrame(timestamp, kWidth, kHeight));
   // Frame should not be dropped, as initial framedropper is off.
   WaitForEncodedFrame(timestamp);

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest,
        FrameDroppedWhenResolutionIncreasesAndLinkAllocationIsLow) {
   const int kMinStartBps360p = 222000;
   fake_encoder_.SetResolutionBitrateLimits(
       {VideoEncoder::ResolutionBitrateLimits(320 * 180, 0, 30000, 400000),
        VideoEncoder::ResolutionBitrateLimits(640 * 360, kMinStartBps360p, 30000,
                                              800000)});

   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       DataRate::BitsPerSec(kMinStartBps360p - 1),  // target_bitrate
       DataRate::BitsPerSec(kMinStartBps360p - 1),  // stable_target_bitrate
       DataRate::BitsPerSec(kMinStartBps360p - 1),  // link_allocation
       0, 0, 0);
   // Frame should not be dropped, bitrate not too low for frame.
   video_source_.IncomingCapturedFrame(CreateFrame(1, 320, 180));
   WaitForEncodedFrame(1);

   // Incoming resolution increases, initial frame drop activates.
   // Frame should be dropped, link allocation too low for frame.
   video_source_.IncomingCapturedFrame(CreateFrame(2, 640, 360));
   ExpectDroppedFrame();

   // Expect sink_wants to specify a scaled frame.
   EXPECT_TRUE_WAIT(video_source_.sink_wants().max_pixel_count < 640 * 360,
                    5000);
   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest,
        FrameNotDroppedWhenResolutionIncreasesAndLinkAllocationIsHigh) {
   const int kMinStartBps360p = 222000;
   fake_encoder_.SetResolutionBitrateLimits(
       {VideoEncoder::ResolutionBitrateLimits(320 * 180, 0, 30000, 400000),
        VideoEncoder::ResolutionBitrateLimits(640 * 360, kMinStartBps360p, 30000,
                                              800000)});

   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       DataRate::BitsPerSec(kMinStartBps360p - 1),  // target_bitrate
       DataRate::BitsPerSec(kMinStartBps360p - 1),  // stable_target_bitrate
       DataRate::BitsPerSec(kMinStartBps360p),      // link_allocation
       0, 0, 0);
   // Frame should not be dropped, bitrate not too low for frame.
   video_source_.IncomingCapturedFrame(CreateFrame(1, 320, 180));
   WaitForEncodedFrame(1);

   // Incoming resolution increases, initial frame drop activates.
   // Frame should be dropped, link allocation not too low for frame.
   video_source_.IncomingCapturedFrame(CreateFrame(2, 640, 360));
   WaitForEncodedFrame(2);

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest, RampsUpInQualityWhenBwIsHigh) {
   webrtc::test::ScopedKeyValueConfig field_trials(
       field_trials_,
       "WebRTC-Video-QualityRampupSettings/"
       "min_pixels:921600,min_duration_ms:2000/");

   const int kWidth = 1280;
   const int kHeight = 720;
   const int kFps = 10;
   max_framerate_ = kFps;

   // Reset encoder for field trials to take effect.
   VideoEncoderConfig config = video_encoder_config_.Copy();
   config.max_bitrate_bps = kTargetBitrate.bps();
   DataRate max_bitrate = DataRate::BitsPerSec(config.max_bitrate_bps);
   ConfigureEncoder(std::move(config));
   fake_encoder_.SetQp(kQpLow);

   // Enable MAINTAIN_FRAMERATE preference.
   AdaptingFrameForwarder source(&time_controller_);
   source.set_adaptation_enabled(true);
   video_stream_encoder_->SetSource(&source,
                                    DegradationPreference::MAINTAIN_FRAMERATE);

   // Start at low bitrate.
   const DataRate kLowBitrate = DataRate::KilobitsPerSec(200);
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kLowBitrate, kLowBitrate, kLowBitrate, 0, 0, 0);

   // Expect first frame to be dropped and resolution to be limited.
   const int64_t kFrameIntervalMs = 1000 / kFps;
   int64_t timestamp_ms = kFrameIntervalMs;
   source.IncomingCapturedFrame(CreateFrame(timestamp_ms, kWidth, kHeight));
   ExpectDroppedFrame();
   EXPECT_TRUE_WAIT(source.sink_wants().max_pixel_count < kWidth * kHeight,
                    5000);

   // Increase bitrate to encoder max.
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       max_bitrate, max_bitrate, max_bitrate, 0, 0, 0);

   // Insert frames and advance `min_duration_ms`.
   const int64_t start_bw_high_ms = CurrentTimeMs();
   for (size_t i = 1; i <= 10; i++) {
     timestamp_ms += kFrameIntervalMs;
     source.IncomingCapturedFrame(CreateFrame(timestamp_ms, kWidth, kHeight));
     WaitForEncodedFrame(timestamp_ms);
   }

   // Advance to `min_duration_ms` - 1, frame should not trigger high BW.
   int64_t elapsed_bw_high_ms = CurrentTimeMs() - start_bw_high_ms;
   AdvanceTime(TimeDelta::Millis(2000 - elapsed_bw_high_ms - 1));
   timestamp_ms += kFrameIntervalMs;
   source.IncomingCapturedFrame(CreateFrame(timestamp_ms, kWidth, kHeight));
   WaitForEncodedFrame(timestamp_ms);
   EXPECT_TRUE(stats_proxy_->GetStats().bw_limited_resolution);
   EXPECT_LT(source.sink_wants().max_pixel_count, kWidth * kHeight);

   // Frame should trigger high BW and release quality limitation.
   timestamp_ms += kFrameIntervalMs;
   source.IncomingCapturedFrame(CreateFrame(timestamp_ms, kWidth, kHeight));
   WaitForEncodedFrame(timestamp_ms);
   // The ramp-up code involves the adaptation queue, give it time to execute.
   // TODO(hbos): Can we await an appropriate event instead?
   video_stream_encoder_->WaitUntilTaskQueueIsIdle();
   EXPECT_THAT(source.sink_wants(), FpsMaxResolutionMax());

   // Frame should not be adapted.
   timestamp_ms += kFrameIntervalMs;
   source.IncomingCapturedFrame(CreateFrame(timestamp_ms, kWidth, kHeight));
   WaitForEncodedFrame(kWidth, kHeight);
   EXPECT_FALSE(stats_proxy_->GetStats().bw_limited_resolution);

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest,
        QualityScalerAdaptationsRemovedWhenQualityScalingDisabled) {
   webrtc::test::ScopedKeyValueConfig field_trials(
       field_trials_, "WebRTC-Video-QualityScaling/Disabled/");
   AdaptingFrameForwarder source(&time_controller_);
   source.set_adaptation_enabled(true);
   video_stream_encoder_->SetSource(&source,
                                    DegradationPreference::MAINTAIN_FRAMERATE);
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);
   fake_encoder_.SetQp(kQpHigh + 1);
   const int kWidth = 1280;
   const int kHeight = 720;
   const int64_t kFrameIntervalMs = 100;
   int64_t timestamp_ms = kFrameIntervalMs;
   for (size_t i = 1; i <= 100; i++) {
     timestamp_ms += kFrameIntervalMs;
     source.IncomingCapturedFrame(CreateFrame(timestamp_ms, kWidth, kHeight));
     WaitForEncodedFrame(timestamp_ms);
   }
   // Wait for QualityScaler, which will wait for 2000*2.5 ms until checking QP
   // for the first time.
   // TODO(eshr): We should avoid these waits by using threads with simulated
   // time.
   EXPECT_TRUE_WAIT(stats_proxy_->GetStats().bw_limited_resolution,
                    2000 * 2.5 * 2);
   timestamp_ms += kFrameIntervalMs;
   source.IncomingCapturedFrame(CreateFrame(timestamp_ms, kWidth, kHeight));
   WaitForEncodedFrame(timestamp_ms);
   video_stream_encoder_->WaitUntilTaskQueueIsIdle();
   EXPECT_THAT(source.sink_wants(), WantsMaxPixels(Lt(kWidth * kHeight)));
   EXPECT_TRUE(stats_proxy_->GetStats().bw_limited_resolution);

   // Disable Quality scaling by turning off scaler on the encoder and
   // reconfiguring.
   fake_encoder_.SetQualityScaling(false);
   video_stream_encoder_->ConfigureEncoder(video_encoder_config_.Copy(),
                                           kMaxPayloadLength);
   video_stream_encoder_->WaitUntilTaskQueueIsIdle();
   AdvanceTime(TimeDelta::Zero());
   // Since we turned off the quality scaler, the adaptations made by it are
   // removed.
   EXPECT_THAT(source.sink_wants(), ResolutionMax());
   EXPECT_FALSE(stats_proxy_->GetStats().bw_limited_resolution);

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest,
        ResolutionNotAdaptedForTooSmallFrame_MaintainFramerateMode) {
   const int kTooSmallWidth = 10;
   const int kTooSmallHeight = 10;
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);

   // Enable MAINTAIN_FRAMERATE preference, no initial limitation.
   test::FrameForwarder source;
   video_stream_encoder_->SetSource(
       &source, webrtc::DegradationPreference::MAINTAIN_FRAMERATE);
   EXPECT_THAT(source.sink_wants(), UnlimitedSinkWants());
   EXPECT_FALSE(stats_proxy_->GetStats().cpu_limited_resolution);

   // Trigger adapt down, too small frame, expect no change.
   source.IncomingCapturedFrame(CreateFrame(1, kTooSmallWidth, kTooSmallHeight));
   WaitForEncodedFrame(1);
   video_stream_encoder_->TriggerCpuOveruse();
   EXPECT_THAT(source.sink_wants(), FpsMaxResolutionMax());
   EXPECT_FALSE(stats_proxy_->GetStats().cpu_limited_resolution);
   EXPECT_EQ(0, stats_proxy_->GetStats().number_of_cpu_adapt_changes);

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest,
        ResolutionNotAdaptedForTooSmallFrame_BalancedMode) {
   const int kTooSmallWidth = 10;
   const int kTooSmallHeight = 10;
   const int kFpsLimit = 7;
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);

   // Enable BALANCED preference, no initial limitation.
   test::FrameForwarder source;
   video_stream_encoder_->SetSource(&source,
                                    webrtc::DegradationPreference::BALANCED);
   EXPECT_THAT(source.sink_wants(), UnlimitedSinkWants());
   EXPECT_FALSE(stats_proxy_->GetStats().bw_limited_resolution);
   EXPECT_FALSE(stats_proxy_->GetStats().bw_limited_framerate);

   // Trigger adapt down, expect limited framerate.
   source.IncomingCapturedFrame(CreateFrame(1, kTooSmallWidth, kTooSmallHeight));
   WaitForEncodedFrame(1);
   video_stream_encoder_->TriggerQualityLow();
   EXPECT_THAT(source.sink_wants(), FpsMatchesResolutionMax(Eq(kFpsLimit)));
   EXPECT_FALSE(stats_proxy_->GetStats().bw_limited_resolution);
   EXPECT_TRUE(stats_proxy_->GetStats().bw_limited_framerate);
   EXPECT_EQ(1, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   // Trigger adapt down, too small frame, expect no change.
   source.IncomingCapturedFrame(CreateFrame(2, kTooSmallWidth, kTooSmallHeight));
   WaitForEncodedFrame(2);
   video_stream_encoder_->TriggerQualityLow();
   EXPECT_THAT(source.sink_wants(), FpsMatchesResolutionMax(Eq(kFpsLimit)));
   EXPECT_FALSE(stats_proxy_->GetStats().bw_limited_resolution);
   EXPECT_TRUE(stats_proxy_->GetStats().bw_limited_framerate);
   EXPECT_EQ(1, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest, FailingInitEncodeDoesntCauseCrash) {
   fake_encoder_.ForceInitEncodeFailure(true);
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);
   ResetEncoder("VP8", 2, 1, 1, false);
   const int kFrameWidth = 1280;
   const int kFrameHeight = 720;
   video_source_.IncomingCapturedFrame(
       CreateFrame(1, kFrameWidth, kFrameHeight));
   ExpectDroppedFrame();
   video_stream_encoder_->Stop();
 }

 // TODO(sprang): Extend this with fps throttling and any "balanced" extensions.
 TEST_F(VideoStreamEncoderTest,
        AdaptsResolutionOnOveruse_MaintainFramerateMode) {
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);

   const int kFrameWidth = 1280;
   const int kFrameHeight = 720;
   // Enabled default VideoAdapter downscaling. First step is 3/4, not 3/5 as
   // requested by
   // VideoStreamEncoder::VideoSourceProxy::RequestResolutionLowerThan().
   video_source_.set_adaptation_enabled(true);

   video_source_.IncomingCapturedFrame(
       CreateFrame(1 * kFrameIntervalMs, kFrameWidth, kFrameHeight));
   WaitForEncodedFrame(kFrameWidth, kFrameHeight);

   // Trigger CPU overuse, downscale by 3/4.
   video_stream_encoder_->TriggerCpuOveruse();
   video_source_.IncomingCapturedFrame(
       CreateFrame(2 * kFrameIntervalMs, kFrameWidth, kFrameHeight));
   WaitForEncodedFrame((kFrameWidth * 3) / 4, (kFrameHeight * 3) / 4);

   // Trigger CPU normal use, return to original resolution.
   video_stream_encoder_->TriggerCpuUnderuse();
   video_source_.IncomingCapturedFrame(
       CreateFrame(3 * kFrameIntervalMs, kFrameWidth, kFrameHeight));
   WaitForEncodedFrame(kFrameWidth, kFrameHeight);

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest,
        AdaptsFramerateOnOveruse_MaintainResolutionMode) {
   const int kFrameWidth = 1280;
   const int kFrameHeight = 720;

   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);
   video_stream_encoder_->SetSource(
       &video_source_, webrtc::DegradationPreference::MAINTAIN_RESOLUTION);
   video_source_.set_adaptation_enabled(true);

   int64_t timestamp_ms = CurrentTimeMs();

   video_source_.IncomingCapturedFrame(
       CreateFrame(timestamp_ms, kFrameWidth, kFrameHeight));
   WaitForEncodedFrame(timestamp_ms);

   // Try to trigger overuse. No fps estimate available => no effect.
   video_stream_encoder_->TriggerCpuOveruse();

   // Insert frames for one second to get a stable estimate.
   for (int i = 0; i < max_framerate_; ++i) {
     timestamp_ms += kFrameIntervalMs;
     video_source_.IncomingCapturedFrame(
         CreateFrame(timestamp_ms, kFrameWidth, kFrameHeight));
     WaitForEncodedFrame(timestamp_ms);
   }

   // Trigger CPU overuse, reduce framerate by 2/3.
   video_stream_encoder_->TriggerCpuOveruse();
   int num_frames_dropped = 0;
   for (int i = 0; i < max_framerate_; ++i) {
     timestamp_ms += kFrameIntervalMs;
     video_source_.IncomingCapturedFrame(
         CreateFrame(timestamp_ms, kFrameWidth, kFrameHeight));
     if (!WaitForFrame(kFrameTimeout)) {
       ++num_frames_dropped;
     } else {
       sink_.CheckLastFrameSizeMatches(kFrameWidth, kFrameHeight);
     }
   }

   // Add some slack to account for frames dropped by the frame dropper.
   const int kErrorMargin = 1;
   EXPECT_NEAR(num_frames_dropped, max_framerate_ - (max_framerate_ * 2 / 3),
               kErrorMargin);

   // Trigger CPU overuse, reduce framerate by 2/3 again.
   video_stream_encoder_->TriggerCpuOveruse();
   num_frames_dropped = 0;
   for (int i = 0; i <= max_framerate_; ++i) {
     timestamp_ms += kFrameIntervalMs;
     video_source_.IncomingCapturedFrame(
         CreateFrame(timestamp_ms, kFrameWidth, kFrameHeight));
     if (!WaitForFrame(kFrameTimeout)) {
       ++num_frames_dropped;
     } else {
       sink_.CheckLastFrameSizeMatches(kFrameWidth, kFrameHeight);
     }
   }
   EXPECT_NEAR(num_frames_dropped, max_framerate_ - (max_framerate_ * 4 / 9),
               kErrorMargin);

   // Go back up one step.
   video_stream_encoder_->TriggerCpuUnderuse();
   num_frames_dropped = 0;
   for (int i = 0; i < max_framerate_; ++i) {
     timestamp_ms += kFrameIntervalMs;
     video_source_.IncomingCapturedFrame(
         CreateFrame(timestamp_ms, kFrameWidth, kFrameHeight));
     if (!WaitForFrame(kFrameTimeout)) {
       ++num_frames_dropped;
     } else {
       sink_.CheckLastFrameSizeMatches(kFrameWidth, kFrameHeight);
     }
   }
   EXPECT_NEAR(num_frames_dropped, max_framerate_ - (max_framerate_ * 2 / 3),
               kErrorMargin);

   // Go back up to original mode.
   video_stream_encoder_->TriggerCpuUnderuse();
   num_frames_dropped = 0;
   for (int i = 0; i < max_framerate_; ++i) {
     timestamp_ms += kFrameIntervalMs;
     video_source_.IncomingCapturedFrame(
         CreateFrame(timestamp_ms, kFrameWidth, kFrameHeight));
     if (!WaitForFrame(kFrameTimeout)) {
       ++num_frames_dropped;
     } else {
       sink_.CheckLastFrameSizeMatches(kFrameWidth, kFrameHeight);
     }
   }
   EXPECT_NEAR(num_frames_dropped, 0, kErrorMargin);

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest, DoesntAdaptDownPastMinFramerate) {
   const int kFramerateFps = 5;
   const int kFrameIntervalMs = rtc::kNumMillisecsPerSec / kFramerateFps;
   const int kFrameWidth = 1280;
   const int kFrameHeight = 720;

   // Reconfigure encoder with two temporal layers and screensharing, which will
   // disable frame dropping and make testing easier.
   ResetEncoder("VP8", 1, 2, 1, true);

   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);
   video_stream_encoder_->SetSource(
       &video_source_, webrtc::DegradationPreference::MAINTAIN_RESOLUTION);
   video_source_.set_adaptation_enabled(true);

   int64_t timestamp_ms = CurrentTimeMs();

   // Trigger overuse as much as we can.
   rtc::VideoSinkWants last_wants;
   do {
     last_wants = video_source_.sink_wants();

     // Insert frames to get a new fps estimate...
     for (int j = 0; j < kFramerateFps; ++j) {
       video_source_.IncomingCapturedFrame(
           CreateFrame(timestamp_ms, kFrameWidth, kFrameHeight));
       if (video_source_.last_sent_width()) {
         sink_.WaitForEncodedFrame(timestamp_ms);
       }
       timestamp_ms += kFrameIntervalMs;
       AdvanceTime(TimeDelta::Millis(kFrameIntervalMs));
     }
     // ...and then try to adapt again.
     video_stream_encoder_->TriggerCpuOveruse();
   } while (video_source_.sink_wants().max_framerate_fps <
            last_wants.max_framerate_fps);

   EXPECT_THAT(video_source_.sink_wants(),
               FpsMatchesResolutionMax(Eq(kMinFramerateFps)));

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest,
        AdaptsResolutionAndFramerateForLowQuality_BalancedMode) {
   const int kWidth = 1280;
   const int kHeight = 720;
   const int64_t kFrameIntervalMs = 150;
   int64_t timestamp_ms = kFrameIntervalMs;
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);

   // Enable BALANCED preference, no initial limitation.
   AdaptingFrameForwarder source(&time_controller_);
   source.set_adaptation_enabled(true);
   video_stream_encoder_->SetSource(&source,
                                    webrtc::DegradationPreference::BALANCED);
   timestamp_ms += kFrameIntervalMs;
   source.IncomingCapturedFrame(CreateFrame(timestamp_ms, kWidth, kHeight));
   WaitForEncodedFrame(kWidth, kHeight);
   EXPECT_THAT(source.sink_wants(), FpsMaxResolutionMax());
   EXPECT_FALSE(stats_proxy_->GetStats().bw_limited_resolution);
   EXPECT_FALSE(stats_proxy_->GetStats().bw_limited_framerate);
   EXPECT_EQ(0, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   // Trigger adapt down, expect scaled down resolution (960x540@30fps).
   video_stream_encoder_->TriggerQualityLow();
   timestamp_ms += kFrameIntervalMs;
   source.IncomingCapturedFrame(CreateFrame(timestamp_ms, kWidth, kHeight));
   WaitForEncodedFrame(timestamp_ms);
   EXPECT_THAT(source.sink_wants(),
               FpsMaxResolutionMatches(Lt(kWidth * kHeight)));
   EXPECT_TRUE(stats_proxy_->GetStats().bw_limited_resolution);
   EXPECT_FALSE(stats_proxy_->GetStats().bw_limited_framerate);
   EXPECT_EQ(1, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   // Trigger adapt down, expect scaled down resolution (640x360@30fps).
   video_stream_encoder_->TriggerQualityLow();
   timestamp_ms += kFrameIntervalMs;
   source.IncomingCapturedFrame(CreateFrame(timestamp_ms, kWidth, kHeight));
   WaitForEncodedFrame(timestamp_ms);
   EXPECT_THAT(source.sink_wants(), FpsMaxResolutionLt(source.last_wants()));
   EXPECT_TRUE(stats_proxy_->GetStats().bw_limited_resolution);
   EXPECT_FALSE(stats_proxy_->GetStats().bw_limited_framerate);
   EXPECT_EQ(2, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   // Trigger adapt down, expect reduced fps (640x360@15fps).
   video_stream_encoder_->TriggerQualityLow();
   timestamp_ms += kFrameIntervalMs;
   source.IncomingCapturedFrame(CreateFrame(timestamp_ms, kWidth, kHeight));
   WaitForEncodedFrame(timestamp_ms);
   EXPECT_THAT(source.sink_wants(), FpsLtResolutionEq(source.last_wants()));
   EXPECT_TRUE(stats_proxy_->GetStats().bw_limited_resolution);
   EXPECT_TRUE(stats_proxy_->GetStats().bw_limited_framerate);
   EXPECT_EQ(3, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   // Trigger adapt down, expect scaled down resolution (480x270@15fps).
   video_stream_encoder_->TriggerQualityLow();
   timestamp_ms += kFrameIntervalMs;
   source.IncomingCapturedFrame(CreateFrame(timestamp_ms, kWidth, kHeight));
   WaitForEncodedFrame(timestamp_ms);
   EXPECT_THAT(source.sink_wants(), FpsEqResolutionLt(source.last_wants()));
   EXPECT_TRUE(stats_proxy_->GetStats().bw_limited_resolution);
   EXPECT_TRUE(stats_proxy_->GetStats().bw_limited_framerate);
   EXPECT_EQ(4, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   // Restrict bitrate, trigger adapt down, expect reduced fps (480x270@10fps).
   video_stream_encoder_->TriggerQualityLow();
   timestamp_ms += kFrameIntervalMs;
   source.IncomingCapturedFrame(CreateFrame(timestamp_ms, kWidth, kHeight));
   WaitForEncodedFrame(timestamp_ms);
   EXPECT_THAT(source.sink_wants(), FpsLtResolutionEq(source.last_wants()));
   EXPECT_TRUE(stats_proxy_->GetStats().bw_limited_resolution);
   EXPECT_TRUE(stats_proxy_->GetStats().bw_limited_framerate);
   EXPECT_EQ(5, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   // Trigger adapt down, expect scaled down resolution (320x180@10fps).
   video_stream_encoder_->TriggerQualityLow();
   timestamp_ms += kFrameIntervalMs;
   source.IncomingCapturedFrame(CreateFrame(timestamp_ms, kWidth, kHeight));
   WaitForEncodedFrame(timestamp_ms);
   EXPECT_THAT(source.sink_wants(), FpsEqResolutionLt(source.last_wants()));
   EXPECT_TRUE(stats_proxy_->GetStats().bw_limited_resolution);
   EXPECT_TRUE(stats_proxy_->GetStats().bw_limited_framerate);
   EXPECT_EQ(6, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   // Trigger adapt down, expect reduced fps (320x180@7fps).
   video_stream_encoder_->TriggerQualityLow();
   timestamp_ms += kFrameIntervalMs;
   source.IncomingCapturedFrame(CreateFrame(timestamp_ms, kWidth, kHeight));
   WaitForEncodedFrame(timestamp_ms);
   EXPECT_THAT(source.sink_wants(), FpsLtResolutionEq(source.last_wants()));
   rtc::VideoSinkWants last_wants = source.sink_wants();
   EXPECT_TRUE(stats_proxy_->GetStats().bw_limited_resolution);
   EXPECT_TRUE(stats_proxy_->GetStats().bw_limited_framerate);
   EXPECT_EQ(7, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   // Trigger adapt down, min resolution reached, expect no change.
   video_stream_encoder_->TriggerQualityLow();
   timestamp_ms += kFrameIntervalMs;
   source.IncomingCapturedFrame(CreateFrame(timestamp_ms, kWidth, kHeight));
   WaitForEncodedFrame(timestamp_ms);
   EXPECT_THAT(source.sink_wants(), FpsEqResolutionEqTo(last_wants));
   EXPECT_TRUE(stats_proxy_->GetStats().bw_limited_resolution);
   EXPECT_TRUE(stats_proxy_->GetStats().bw_limited_framerate);
   EXPECT_EQ(7, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   // Trigger adapt up, expect increased fps (320x180@10fps).
   video_stream_encoder_->TriggerQualityHigh();
   timestamp_ms += kFrameIntervalMs;
   source.IncomingCapturedFrame(CreateFrame(timestamp_ms, kWidth, kHeight));
   WaitForEncodedFrame(timestamp_ms);
   EXPECT_THAT(source.sink_wants(), FpsGtResolutionEq(source.last_wants()));
   EXPECT_TRUE(stats_proxy_->GetStats().bw_limited_resolution);
   EXPECT_TRUE(stats_proxy_->GetStats().bw_limited_framerate);
   EXPECT_EQ(8, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   // Trigger adapt up, expect upscaled resolution (480x270@10fps).
   video_stream_encoder_->TriggerQualityHigh();
   timestamp_ms += kFrameIntervalMs;
   source.IncomingCapturedFrame(CreateFrame(timestamp_ms, kWidth, kHeight));
   WaitForEncodedFrame(timestamp_ms);
   EXPECT_THAT(source.sink_wants(), FpsEqResolutionGt(source.last_wants()));
   EXPECT_TRUE(stats_proxy_->GetStats().bw_limited_resolution);
   EXPECT_TRUE(stats_proxy_->GetStats().bw_limited_framerate);
   EXPECT_EQ(9, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   // Increase bitrate, trigger adapt up, expect increased fps (480x270@15fps).
   video_stream_encoder_->TriggerQualityHigh();
   timestamp_ms += kFrameIntervalMs;
   source.IncomingCapturedFrame(CreateFrame(timestamp_ms, kWidth, kHeight));
   WaitForEncodedFrame(timestamp_ms);
   EXPECT_THAT(source.sink_wants(), FpsGtResolutionEq(source.last_wants()));
   EXPECT_TRUE(stats_proxy_->GetStats().bw_limited_resolution);
   EXPECT_TRUE(stats_proxy_->GetStats().bw_limited_framerate);
   EXPECT_EQ(10, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   // Trigger adapt up, expect upscaled resolution (640x360@15fps).
   video_stream_encoder_->TriggerQualityHigh();
   timestamp_ms += kFrameIntervalMs;
   source.IncomingCapturedFrame(CreateFrame(timestamp_ms, kWidth, kHeight));
   WaitForEncodedFrame(timestamp_ms);
   EXPECT_THAT(source.sink_wants(), FpsEqResolutionGt(source.last_wants()));
   EXPECT_TRUE(stats_proxy_->GetStats().bw_limited_resolution);
   EXPECT_TRUE(stats_proxy_->GetStats().bw_limited_framerate);
   EXPECT_EQ(11, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   // Trigger adapt up, expect increased fps (640x360@30fps).
   video_stream_encoder_->TriggerQualityHigh();
   timestamp_ms += kFrameIntervalMs;
   source.IncomingCapturedFrame(CreateFrame(timestamp_ms, kWidth, kHeight));
   WaitForEncodedFrame(timestamp_ms);
   EXPECT_THAT(source.sink_wants(), FpsMax());
   EXPECT_EQ(source.sink_wants().max_pixel_count,
             source.last_wants().max_pixel_count);
   EXPECT_TRUE(stats_proxy_->GetStats().bw_limited_resolution);
   EXPECT_FALSE(stats_proxy_->GetStats().bw_limited_framerate);
   EXPECT_EQ(12, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   // Trigger adapt up, expect upscaled resolution (960x540@30fps).
   video_stream_encoder_->TriggerQualityHigh();
   timestamp_ms += kFrameIntervalMs;
   source.IncomingCapturedFrame(CreateFrame(timestamp_ms, kWidth, kHeight));
   WaitForEncodedFrame(timestamp_ms);
   EXPECT_THAT(source.sink_wants(), FpsMaxResolutionGt(source.last_wants()));
   EXPECT_TRUE(stats_proxy_->GetStats().bw_limited_resolution);
   EXPECT_FALSE(stats_proxy_->GetStats().bw_limited_framerate);
   EXPECT_EQ(13, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   // Trigger adapt up, expect no restriction (1280x720fps@30fps).
   video_stream_encoder_->TriggerQualityHigh();
   timestamp_ms += kFrameIntervalMs;
   source.IncomingCapturedFrame(CreateFrame(timestamp_ms, kWidth, kHeight));
   WaitForEncodedFrame(kWidth, kHeight);
   EXPECT_THAT(source.sink_wants(), FpsMaxResolutionGt(source.last_wants()));
   EXPECT_THAT(source.sink_wants(), FpsMaxResolutionMax());
   EXPECT_FALSE(stats_proxy_->GetStats().bw_limited_resolution);
   EXPECT_FALSE(stats_proxy_->GetStats().bw_limited_framerate);
   EXPECT_EQ(14, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   // Trigger adapt up, expect no change.
   video_stream_encoder_->TriggerQualityHigh();
   EXPECT_THAT(source.sink_wants(), FpsMaxResolutionMax());
   EXPECT_EQ(14, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest, AdaptWithTwoReasonsAndDifferentOrder_Framerate) {
   const int kWidth = 1280;
   const int kHeight = 720;
   const int64_t kFrameIntervalMs = 150;
   int64_t timestamp_ms = kFrameIntervalMs;
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);

   // Enable BALANCED preference, no initial limitation.
   AdaptingFrameForwarder source(&time_controller_);
   source.set_adaptation_enabled(true);
   video_stream_encoder_->SetSource(&source,
                                    webrtc::DegradationPreference::BALANCED);
   timestamp_ms += kFrameIntervalMs;
   source.IncomingCapturedFrame(CreateFrame(timestamp_ms, kWidth, kHeight));
   WaitForEncodedFrame(kWidth, kHeight);
   EXPECT_THAT(source.sink_wants(), FpsMaxResolutionMax());
   EXPECT_FALSE(stats_proxy_->GetStats().bw_limited_resolution);
   EXPECT_FALSE(stats_proxy_->GetStats().bw_limited_framerate);
   EXPECT_FALSE(stats_proxy_->GetStats().cpu_limited_resolution);
   EXPECT_FALSE(stats_proxy_->GetStats().cpu_limited_framerate);
   EXPECT_EQ(0, stats_proxy_->GetStats().number_of_cpu_adapt_changes);
   EXPECT_EQ(0, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   // Trigger cpu adapt down, expect scaled down resolution (960x540@30fps).
   video_stream_encoder_->TriggerCpuOveruse();
   timestamp_ms += kFrameIntervalMs;
   source.IncomingCapturedFrame(CreateFrame(timestamp_ms, kWidth, kHeight));
   WaitForEncodedFrame(timestamp_ms);
   EXPECT_THAT(source.sink_wants(),
               FpsMaxResolutionMatches(Lt(kWidth * kHeight)));
   EXPECT_FALSE(stats_proxy_->GetStats().bw_limited_resolution);
   EXPECT_FALSE(stats_proxy_->GetStats().bw_limited_framerate);
   EXPECT_TRUE(stats_proxy_->GetStats().cpu_limited_resolution);
   EXPECT_FALSE(stats_proxy_->GetStats().cpu_limited_framerate);
   EXPECT_EQ(1, stats_proxy_->GetStats().number_of_cpu_adapt_changes);
   EXPECT_EQ(0, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   // Trigger cpu adapt down, expect scaled down resolution (640x360@30fps).
   video_stream_encoder_->TriggerCpuOveruse();
   timestamp_ms += kFrameIntervalMs;
   source.IncomingCapturedFrame(CreateFrame(timestamp_ms, kWidth, kHeight));
   WaitForEncodedFrame(timestamp_ms);
   EXPECT_THAT(source.sink_wants(), FpsMaxResolutionLt(source.last_wants()));
   EXPECT_FALSE(stats_proxy_->GetStats().bw_limited_resolution);
   EXPECT_FALSE(stats_proxy_->GetStats().bw_limited_framerate);
   EXPECT_TRUE(stats_proxy_->GetStats().cpu_limited_resolution);
   EXPECT_FALSE(stats_proxy_->GetStats().cpu_limited_framerate);
   EXPECT_EQ(2, stats_proxy_->GetStats().number_of_cpu_adapt_changes);
   EXPECT_EQ(0, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   // Trigger quality adapt down, expect reduced fps (640x360@15fps).
   video_stream_encoder_->TriggerQualityLow();
   timestamp_ms += kFrameIntervalMs;
   source.IncomingCapturedFrame(CreateFrame(timestamp_ms, kWidth, kHeight));
   WaitForEncodedFrame(timestamp_ms);
   EXPECT_THAT(source.sink_wants(), FpsLtResolutionEq(source.last_wants()));
   EXPECT_TRUE(stats_proxy_->GetStats().bw_limited_resolution);
   EXPECT_TRUE(stats_proxy_->GetStats().bw_limited_framerate);
   EXPECT_TRUE(stats_proxy_->GetStats().cpu_limited_resolution);
   EXPECT_FALSE(stats_proxy_->GetStats().cpu_limited_framerate);
   EXPECT_EQ(2, stats_proxy_->GetStats().number_of_cpu_adapt_changes);
   EXPECT_EQ(1, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   // Trigger cpu adapt up, expect no change since QP is most limited.
   {
     // Store current sink wants since we expect no change and if there is no
     // change then last_wants() is not updated.
     auto previous_sink_wants = source.sink_wants();
     video_stream_encoder_->TriggerCpuUnderuse();
     timestamp_ms += kFrameIntervalMs;
     source.IncomingCapturedFrame(CreateFrame(timestamp_ms, kWidth, kHeight));
     WaitForEncodedFrame(timestamp_ms);
     EXPECT_THAT(source.sink_wants(), FpsEqResolutionEqTo(previous_sink_wants));
     EXPECT_EQ(2, stats_proxy_->GetStats().number_of_cpu_adapt_changes);
     EXPECT_EQ(1, stats_proxy_->GetStats().number_of_quality_adapt_changes);
   }

   // Trigger quality adapt up, expect increased fps (640x360@30fps).
   video_stream_encoder_->TriggerQualityHigh();
   timestamp_ms += kFrameIntervalMs;
   source.IncomingCapturedFrame(CreateFrame(timestamp_ms, kWidth, kHeight));
   WaitForEncodedFrame(timestamp_ms);
   EXPECT_THAT(source.sink_wants(), FpsGtResolutionEq(source.last_wants()));
   EXPECT_TRUE(stats_proxy_->GetStats().bw_limited_resolution);
   EXPECT_FALSE(stats_proxy_->GetStats().bw_limited_framerate);
   EXPECT_TRUE(stats_proxy_->GetStats().cpu_limited_resolution);
   EXPECT_FALSE(stats_proxy_->GetStats().cpu_limited_framerate);
   EXPECT_EQ(2, stats_proxy_->GetStats().number_of_cpu_adapt_changes);
   EXPECT_EQ(2, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   // Trigger quality adapt up and Cpu adapt up since both are most limited,
   // expect increased resolution (960x540@30fps).
   video_stream_encoder_->TriggerQualityHigh();
   video_stream_encoder_->TriggerCpuUnderuse();
   timestamp_ms += kFrameIntervalMs;
   source.IncomingCapturedFrame(CreateFrame(timestamp_ms, kWidth, kHeight));
   WaitForEncodedFrame(timestamp_ms);
   EXPECT_THAT(source.sink_wants(), FpsMaxResolutionGt(source.last_wants()));
   EXPECT_TRUE(stats_proxy_->GetStats().bw_limited_resolution);
   EXPECT_FALSE(stats_proxy_->GetStats().bw_limited_framerate);
   EXPECT_TRUE(stats_proxy_->GetStats().cpu_limited_resolution);
   EXPECT_FALSE(stats_proxy_->GetStats().cpu_limited_framerate);
   EXPECT_EQ(3, stats_proxy_->GetStats().number_of_cpu_adapt_changes);
   EXPECT_EQ(3, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   // Trigger quality adapt up and Cpu adapt up since both are most limited,
   // expect no restriction (1280x720fps@30fps).
   video_stream_encoder_->TriggerQualityHigh();
   video_stream_encoder_->TriggerCpuUnderuse();
   timestamp_ms += kFrameIntervalMs;
   source.IncomingCapturedFrame(CreateFrame(timestamp_ms, kWidth, kHeight));
   WaitForEncodedFrame(kWidth, kHeight);
   EXPECT_THAT(source.sink_wants(), FpsMaxResolutionGt(source.last_wants()));
   EXPECT_THAT(source.sink_wants(), FpsMaxResolutionMax());
   EXPECT_FALSE(stats_proxy_->GetStats().bw_limited_resolution);
   EXPECT_FALSE(stats_proxy_->GetStats().bw_limited_framerate);
   EXPECT_FALSE(stats_proxy_->GetStats().cpu_limited_resolution);
   EXPECT_FALSE(stats_proxy_->GetStats().cpu_limited_framerate);
   EXPECT_EQ(4, stats_proxy_->GetStats().number_of_cpu_adapt_changes);
   EXPECT_EQ(4, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   // Trigger adapt up, expect no change.
   video_stream_encoder_->TriggerQualityHigh();
   EXPECT_THAT(source.sink_wants(), FpsMaxResolutionMax());
   EXPECT_EQ(4, stats_proxy_->GetStats().number_of_cpu_adapt_changes);
   EXPECT_EQ(4, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest,
        AdaptWithTwoReasonsAndDifferentOrder_Resolution) {
   const int kWidth = 640;
   const int kHeight = 360;
   const int kFpsLimit = 15;
   const int64_t kFrameIntervalMs = 150;
   int64_t timestamp_ms = kFrameIntervalMs;
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);

   // Enable BALANCED preference, no initial limitation.
   AdaptingFrameForwarder source(&time_controller_);
   source.set_adaptation_enabled(true);
   video_stream_encoder_->SetSource(&source,
                                    webrtc::DegradationPreference::BALANCED);
   timestamp_ms += kFrameIntervalMs;
   source.IncomingCapturedFrame(CreateFrame(timestamp_ms, kWidth, kHeight));
   WaitForEncodedFrame(kWidth, kHeight);
   EXPECT_THAT(source.sink_wants(), FpsMaxResolutionMax());
   EXPECT_FALSE(stats_proxy_->GetStats().bw_limited_resolution);
   EXPECT_FALSE(stats_proxy_->GetStats().bw_limited_framerate);
   EXPECT_FALSE(stats_proxy_->GetStats().cpu_limited_resolution);
   EXPECT_FALSE(stats_proxy_->GetStats().cpu_limited_framerate);
   EXPECT_EQ(0, stats_proxy_->GetStats().number_of_cpu_adapt_changes);
   EXPECT_EQ(0, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   // Trigger cpu adapt down, expect scaled down framerate (640x360@15fps).
   video_stream_encoder_->TriggerCpuOveruse();
   timestamp_ms += kFrameIntervalMs;
   source.IncomingCapturedFrame(CreateFrame(timestamp_ms, kWidth, kHeight));
   WaitForEncodedFrame(timestamp_ms);
   EXPECT_THAT(source.sink_wants(), FpsMatchesResolutionMax(Eq(kFpsLimit)));
   EXPECT_FALSE(stats_proxy_->GetStats().bw_limited_resolution);
   EXPECT_FALSE(stats_proxy_->GetStats().bw_limited_framerate);
   EXPECT_FALSE(stats_proxy_->GetStats().cpu_limited_resolution);
   EXPECT_TRUE(stats_proxy_->GetStats().cpu_limited_framerate);
   EXPECT_EQ(1, stats_proxy_->GetStats().number_of_cpu_adapt_changes);
   EXPECT_EQ(0, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   // Trigger quality adapt down, expect scaled down resolution (480x270@15fps).
   video_stream_encoder_->TriggerQualityLow();
   timestamp_ms += kFrameIntervalMs;
   source.IncomingCapturedFrame(CreateFrame(timestamp_ms, kWidth, kHeight));
   WaitForEncodedFrame(timestamp_ms);
   EXPECT_THAT(source.sink_wants(), FpsEqResolutionLt(source.last_wants()));
   EXPECT_TRUE(stats_proxy_->GetStats().bw_limited_resolution);
   EXPECT_TRUE(stats_proxy_->GetStats().bw_limited_framerate);
   EXPECT_FALSE(stats_proxy_->GetStats().cpu_limited_resolution);
   EXPECT_TRUE(stats_proxy_->GetStats().cpu_limited_framerate);
   EXPECT_EQ(1, stats_proxy_->GetStats().number_of_cpu_adapt_changes);
   EXPECT_EQ(1, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   // Trigger cpu adapt up, expect no change because quality is most limited.
   {
     auto previous_sink_wants = source.sink_wants();
     // Store current sink wants since we expect no change ind if there is no
     // change then last__wants() is not updated.
     video_stream_encoder_->TriggerCpuUnderuse();
     timestamp_ms += kFrameIntervalMs;
     source.IncomingCapturedFrame(CreateFrame(timestamp_ms, kWidth, kHeight));
     WaitForEncodedFrame(timestamp_ms);
     EXPECT_THAT(source.sink_wants(), FpsEqResolutionEqTo(previous_sink_wants));
     EXPECT_EQ(1, stats_proxy_->GetStats().number_of_cpu_adapt_changes);
     EXPECT_EQ(1, stats_proxy_->GetStats().number_of_quality_adapt_changes);
   }

   // Trigger quality adapt up, expect upscaled resolution (640x360@15fps).
   video_stream_encoder_->TriggerQualityHigh();
   timestamp_ms += kFrameIntervalMs;
   source.IncomingCapturedFrame(CreateFrame(timestamp_ms, kWidth, kHeight));
   WaitForEncodedFrame(timestamp_ms);
   EXPECT_THAT(source.sink_wants(), FpsEqResolutionGt(source.last_wants()));
   EXPECT_FALSE(stats_proxy_->GetStats().bw_limited_resolution);
   EXPECT_TRUE(stats_proxy_->GetStats().bw_limited_framerate);
   EXPECT_FALSE(stats_proxy_->GetStats().cpu_limited_resolution);
   EXPECT_TRUE(stats_proxy_->GetStats().cpu_limited_framerate);
   EXPECT_EQ(1, stats_proxy_->GetStats().number_of_cpu_adapt_changes);
   EXPECT_EQ(2, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   // Trigger quality and cpu adapt up, expect increased fps (640x360@30fps).
   video_stream_encoder_->TriggerQualityHigh();
   video_stream_encoder_->TriggerCpuUnderuse();
   timestamp_ms += kFrameIntervalMs;
   source.IncomingCapturedFrame(CreateFrame(timestamp_ms, kWidth, kHeight));
   WaitForEncodedFrame(timestamp_ms);
   EXPECT_THAT(source.sink_wants(), FpsMaxResolutionMax());
   EXPECT_FALSE(stats_proxy_->GetStats().bw_limited_resolution);
   EXPECT_FALSE(stats_proxy_->GetStats().bw_limited_framerate);
   EXPECT_FALSE(stats_proxy_->GetStats().cpu_limited_resolution);
   EXPECT_FALSE(stats_proxy_->GetStats().cpu_limited_framerate);
   EXPECT_EQ(2, stats_proxy_->GetStats().number_of_cpu_adapt_changes);
   EXPECT_EQ(3, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   // Trigger adapt up, expect no change.
   video_stream_encoder_->TriggerQualityHigh();
   EXPECT_THAT(source.sink_wants(), FpsMaxResolutionMax());
   EXPECT_EQ(2, stats_proxy_->GetStats().number_of_cpu_adapt_changes);
   EXPECT_EQ(3, stats_proxy_->GetStats().number_of_quality_adapt_changes);

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest, AcceptsFullHdAdaptedDownSimulcastFrames) {
   const int kFrameWidth = 1920;
   const int kFrameHeight = 1080;
   // 2/3 of 1920.
   const int kAdaptedFrameWidth = 1280;
   // 2/3 of 1080.
   const int kAdaptedFrameHeight = 720;
   const int kFramerate = 24;

   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);
   // Trigger reconfigure encoder (without resetting the entire instance).
   VideoEncoderConfig video_encoder_config;
   test::FillEncoderConfiguration(kVideoCodecVP8, 1, &video_encoder_config);
   video_encoder_config.simulcast_layers[0].max_framerate = kFramerate;
   video_encoder_config.max_bitrate_bps = kTargetBitrate.bps();
   video_encoder_config.video_stream_factory =
       rtc::make_ref_counted<CroppingVideoStreamFactory>();
   video_stream_encoder_->ConfigureEncoder(std::move(video_encoder_config),
                                           kMaxPayloadLength);
   video_stream_encoder_->WaitUntilTaskQueueIsIdle();

   video_source_.set_adaptation_enabled(true);

   video_source_.IncomingCapturedFrame(
       CreateFrame(1, kFrameWidth, kFrameHeight));
   WaitForEncodedFrame(kFrameWidth, kFrameHeight);

   // Trigger CPU overuse, downscale by 3/4.
   video_stream_encoder_->TriggerCpuOveruse();
   video_source_.IncomingCapturedFrame(
       CreateFrame(2, kFrameWidth, kFrameHeight));
   WaitForEncodedFrame(kAdaptedFrameWidth, kAdaptedFrameHeight);

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest, PeriodicallyUpdatesChannelParameters) {
   const int kFrameWidth = 1280;
   const int kFrameHeight = 720;
   const int kLowFps = 2;
   const int kHighFps = 30;

   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);

   int64_t timestamp_ms = CurrentTimeMs();
   max_framerate_ = kLowFps;

   // Insert 2 seconds of 2fps video.
   for (int i = 0; i < kLowFps * 2; ++i) {
     video_source_.IncomingCapturedFrame(
         CreateFrame(timestamp_ms, kFrameWidth, kFrameHeight));
     WaitForEncodedFrame(timestamp_ms);
     timestamp_ms += 1000 / kLowFps;
   }

   // Make sure encoder is updated with new target.
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);
   video_source_.IncomingCapturedFrame(
       CreateFrame(timestamp_ms, kFrameWidth, kFrameHeight));
   WaitForEncodedFrame(timestamp_ms);
   timestamp_ms += 1000 / kLowFps;

   EXPECT_EQ(kLowFps, fake_encoder_.GetConfiguredInputFramerate());

   // Insert 30fps frames for just a little more than the forced update period.
   const int kVcmTimerIntervalFrames = (kProcessIntervalMs * kHighFps) / 1000;
   constexpr TimeDelta kFrameInterval = TimeDelta::Seconds(1) / kHighFps;
   max_framerate_ = kHighFps;
   for (int i = 0; i < kVcmTimerIntervalFrames + 2; ++i) {
     video_source_.IncomingCapturedFrame(
         CreateFrame(timestamp_ms, kFrameWidth, kFrameHeight));
     // Wait for encoded frame, but skip ahead if it doesn't arrive as it might
     // be dropped if the encoder hans't been updated with the new higher target
     // framerate yet, causing it to overshoot the target bitrate and then
     // suffering the wrath of the media optimizer.
     TimedWaitForEncodedFrame(timestamp_ms, 2 * kFrameInterval);
     timestamp_ms += kFrameInterval.ms();
   }

   // Don expect correct measurement just yet, but it should be higher than
   // before.
   EXPECT_GT(fake_encoder_.GetConfiguredInputFramerate(), kLowFps);

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest, DoesNotUpdateBitrateAllocationWhenSuspended) {
   const int kFrameWidth = 1280;
   const int kFrameHeight = 720;
   ResetEncoder("FAKE", 1, 1, 1, false,
                VideoStreamEncoder::BitrateAllocationCallbackType::
                    kVideoBitrateAllocation);

   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);
   video_stream_encoder_->WaitUntilTaskQueueIsIdle();

   // Insert a first video frame, causes another bitrate update.
   int64_t timestamp_ms = CurrentTimeMs();
   video_source_.IncomingCapturedFrame(
       CreateFrame(timestamp_ms, kFrameWidth, kFrameHeight));
   WaitForEncodedFrame(timestamp_ms);
   EXPECT_EQ(sink_.number_of_bitrate_allocations(), 1);

   // Next, simulate video suspension due to pacer queue overrun.
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       DataRate::Zero(), DataRate::Zero(), DataRate::Zero(), 0, 1, 0);

   // Skip ahead until a new periodic parameter update should have occured.
   timestamp_ms += kProcessIntervalMs;
   AdvanceTime(TimeDelta::Millis(kProcessIntervalMs));

   // No more allocations has been made.
   video_source_.IncomingCapturedFrame(
       CreateFrame(timestamp_ms, kFrameWidth, kFrameHeight));
   ExpectDroppedFrame();
   EXPECT_EQ(sink_.number_of_bitrate_allocations(), 1);

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest,
        DefaultCpuAdaptationThresholdsForSoftwareEncoder) {
   const int kFrameWidth = 1280;
   const int kFrameHeight = 720;
   const CpuOveruseOptions default_options;
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);
   video_source_.IncomingCapturedFrame(
       CreateFrame(1, kFrameWidth, kFrameHeight));
   WaitForEncodedFrame(1);
   EXPECT_EQ(video_stream_encoder_->overuse_detector_proxy_->GetOptions()
                 .low_encode_usage_threshold_percent,
             default_options.low_encode_usage_threshold_percent);
   EXPECT_EQ(video_stream_encoder_->overuse_detector_proxy_->GetOptions()
                 .high_encode_usage_threshold_percent,
             default_options.high_encode_usage_threshold_percent);
   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest,
        HigherCpuAdaptationThresholdsForHardwareEncoder) {
   const int kFrameWidth = 1280;
   const int kFrameHeight = 720;
   CpuOveruseOptions hardware_options;
   hardware_options.low_encode_usage_threshold_percent = 150;
   hardware_options.high_encode_usage_threshold_percent = 200;
   fake_encoder_.SetIsHardwareAccelerated(true);

   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);
   video_source_.IncomingCapturedFrame(
       CreateFrame(1, kFrameWidth, kFrameHeight));
   WaitForEncodedFrame(1);
   EXPECT_EQ(video_stream_encoder_->overuse_detector_proxy_->GetOptions()
                 .low_encode_usage_threshold_percent,
             hardware_options.low_encode_usage_threshold_percent);
   EXPECT_EQ(video_stream_encoder_->overuse_detector_proxy_->GetOptions()
                 .high_encode_usage_threshold_percent,
             hardware_options.high_encode_usage_threshold_percent);
   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest,
        CpuAdaptationThresholdsUpdatesWhenHardwareAccelerationChange) {
   const int kFrameWidth = 1280;
   const int kFrameHeight = 720;

   const CpuOveruseOptions default_options;
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);
   video_source_.IncomingCapturedFrame(
       CreateFrame(1, kFrameWidth, kFrameHeight));
   WaitForEncodedFrame(1);
   EXPECT_EQ(video_stream_encoder_->overuse_detector_proxy_->GetOptions()
                 .low_encode_usage_threshold_percent,
             default_options.low_encode_usage_threshold_percent);
   EXPECT_EQ(video_stream_encoder_->overuse_detector_proxy_->GetOptions()
                 .high_encode_usage_threshold_percent,
             default_options.high_encode_usage_threshold_percent);

   CpuOveruseOptions hardware_options;
   hardware_options.low_encode_usage_threshold_percent = 150;
   hardware_options.high_encode_usage_threshold_percent = 200;
   fake_encoder_.SetIsHardwareAccelerated(true);

   video_source_.IncomingCapturedFrame(
       CreateFrame(2, kFrameWidth, kFrameHeight));
   WaitForEncodedFrame(2);

   EXPECT_EQ(video_stream_encoder_->overuse_detector_proxy_->GetOptions()
                 .low_encode_usage_threshold_percent,
             hardware_options.low_encode_usage_threshold_percent);
   EXPECT_EQ(video_stream_encoder_->overuse_detector_proxy_->GetOptions()
                 .high_encode_usage_threshold_percent,
             hardware_options.high_encode_usage_threshold_percent);

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest, DropsFramesWhenEncoderOvershoots) {
   const int kFrameWidth = 320;
   const int kFrameHeight = 240;
   const int kFps = 30;
   const DataRate kTargetBitrate = DataRate::KilobitsPerSec(120);
   const int kNumFramesInRun = kFps * 5;  // Runs of five seconds.

   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);

   int64_t timestamp_ms = CurrentTimeMs();
   max_framerate_ = kFps;

   // Insert 3 seconds of video, verify number of drops with normal bitrate.
   fake_encoder_.SimulateOvershoot(1.0);
   int num_dropped = 0;
   for (int i = 0; i < kNumFramesInRun; ++i) {
     video_source_.IncomingCapturedFrame(
         CreateFrame(timestamp_ms, kFrameWidth, kFrameHeight));
     // Wait up to two frame durations for a frame to arrive.
     if (!TimedWaitForEncodedFrame(timestamp_ms,
                                   2 * TimeDelta::Seconds(1) / kFps)) {
       ++num_dropped;
     }
     timestamp_ms += 1000 / kFps;
   }

   // Framerate should be measured to be near the expected target rate.
   EXPECT_NEAR(fake_encoder_.GetLastFramerate(), kFps, 1);

   // Frame drops should be within 5% of expected 0%.
   EXPECT_NEAR(num_dropped, 0, 5 * kNumFramesInRun / 100);

   // Make encoder produce frames at double the expected bitrate during 3 seconds
   // of video, verify number of drops. Rate needs to be slightly changed in
   // order to force the rate to be reconfigured.
   double overshoot_factor = 2.0;
   const RateControlSettings trials =
       RateControlSettings::ParseFromFieldTrials();
   if (trials.UseEncoderBitrateAdjuster()) {
     // With bitrate adjuster, when need to overshoot even more to trigger
     // frame dropping since the adjuter will try to just lower the target
     // bitrate rather than drop frames. If network headroom can be used, it
     // doesn't push back as hard so we don't need quite as much overshoot.
     // These numbers are unfortunately a bit magical but there's not trivial
     // way to algebraically infer them.
     overshoot_factor = 3.0;
   }
   fake_encoder_.SimulateOvershoot(overshoot_factor);
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate + DataRate::KilobitsPerSec(1),
       kTargetBitrate + DataRate::KilobitsPerSec(1),
       kTargetBitrate + DataRate::KilobitsPerSec(1), 0, 0, 0);
   num_dropped = 0;
   for (int i = 0; i < kNumFramesInRun; ++i) {
     video_source_.IncomingCapturedFrame(
         CreateFrame(timestamp_ms, kFrameWidth, kFrameHeight));
     // Wait up to two frame durations for a frame to arrive.
     if (!TimedWaitForEncodedFrame(timestamp_ms,
                                   2 * TimeDelta::Seconds(1) / kFps)) {
       ++num_dropped;
     }
     timestamp_ms += 1000 / kFps;
   }

   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);

   // Target framerate should be still be near the expected target, despite
   // the frame drops.
   EXPECT_NEAR(fake_encoder_.GetLastFramerate(), kFps, 1);

   // Frame drops should be within 5% of expected 50%.
   EXPECT_NEAR(num_dropped, kNumFramesInRun / 2, 5 * kNumFramesInRun / 100);

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest, ConfiguresCorrectFrameRate) {
   const int kFrameWidth = 320;
   const int kFrameHeight = 240;
   const int kActualInputFps = 24;
   const DataRate kTargetBitrate = DataRate::KilobitsPerSec(120);

   ASSERT_GT(max_framerate_, kActualInputFps);

   int64_t timestamp_ms = CurrentTimeMs();
   max_framerate_ = kActualInputFps;
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);

   // Insert 3 seconds of video, with an input fps lower than configured max.
   for (int i = 0; i < kActualInputFps * 3; ++i) {
     video_source_.IncomingCapturedFrame(
         CreateFrame(timestamp_ms, kFrameWidth, kFrameHeight));
     // Wait up to two frame durations for a frame to arrive.
     WaitForEncodedFrame(timestamp_ms);
     timestamp_ms += 1000 / kActualInputFps;
   }

   EXPECT_NEAR(kActualInputFps, fake_encoder_.GetLastFramerate(), 1);

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest, AccumulatesUpdateRectOnDroppedFrames) {
   VideoFrame::UpdateRect rect;
   test::FrameForwarder source;
   video_stream_encoder_->SetSource(&source,
                                    DegradationPreference::MAINTAIN_FRAMERATE);
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);

   source.IncomingCapturedFrame(CreateFrameWithUpdatedPixel(1, nullptr, 0));
   WaitForEncodedFrame(1);
   // On the very first frame full update should be forced.
   rect = fake_encoder_.GetLastUpdateRect();
   EXPECT_EQ(rect.offset_x, 0);
   EXPECT_EQ(rect.offset_y, 0);
   EXPECT_EQ(rect.height, codec_height_);
   EXPECT_EQ(rect.width, codec_width_);
   // Frame with NTP timestamp 2 will be dropped due to outstanding frames
   // scheduled for processing during encoder queue processing of frame 2.
   source.IncomingCapturedFrame(CreateFrameWithUpdatedPixel(2, nullptr, 1));
   source.IncomingCapturedFrame(CreateFrameWithUpdatedPixel(3, nullptr, 10));
   WaitForEncodedFrame(3);
   // Updates to pixels 1 and 10 should be accumulated to one 10x1 rect.
   rect = fake_encoder_.GetLastUpdateRect();
   EXPECT_EQ(rect.offset_x, 1);
   EXPECT_EQ(rect.offset_y, 0);
   EXPECT_EQ(rect.width, 10);
   EXPECT_EQ(rect.height, 1);

   source.IncomingCapturedFrame(CreateFrameWithUpdatedPixel(4, nullptr, 0));
   WaitForEncodedFrame(4);
   // Previous frame was encoded, so no accumulation should happen.
   rect = fake_encoder_.GetLastUpdateRect();
   EXPECT_EQ(rect.offset_x, 0);
   EXPECT_EQ(rect.offset_y, 0);
   EXPECT_EQ(rect.width, 1);
   EXPECT_EQ(rect.height, 1);

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest, SetsFrameTypes) {
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);

   // First frame is always keyframe.
   video_source_.IncomingCapturedFrame(CreateFrame(1, nullptr));
   WaitForEncodedFrame(1);
   EXPECT_THAT(
       fake_encoder_.LastFrameTypes(),
       ::testing::ElementsAre(VideoFrameType{VideoFrameType::kVideoFrameKey}));

   // Insert delta frame.
   video_source_.IncomingCapturedFrame(CreateFrame(2, nullptr));
   WaitForEncodedFrame(2);
   EXPECT_THAT(
       fake_encoder_.LastFrameTypes(),
       ::testing::ElementsAre(VideoFrameType{VideoFrameType::kVideoFrameDelta}));

   // Request next frame be a key-frame.
   video_stream_encoder_->SendKeyFrame();
   video_source_.IncomingCapturedFrame(CreateFrame(3, nullptr));
   WaitForEncodedFrame(3);
   EXPECT_THAT(
       fake_encoder_.LastFrameTypes(),
       ::testing::ElementsAre(VideoFrameType{VideoFrameType::kVideoFrameKey}));

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest, SetsFrameTypesSimulcast) {
   // Setup simulcast with three streams.
   ResetEncoder("VP8", 3, 1, 1, false);
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kSimulcastTargetBitrate, kSimulcastTargetBitrate, kSimulcastTargetBitrate,
       0, 0, 0);
   // Wait for all three layers before triggering event.
   sink_.SetNumExpectedLayers(3);

   // First frame is always keyframe.
   video_source_.IncomingCapturedFrame(CreateFrame(1, nullptr));
   WaitForEncodedFrame(1);
   EXPECT_THAT(fake_encoder_.LastFrameTypes(),
               ::testing::ElementsAreArray({VideoFrameType::kVideoFrameKey,
                                            VideoFrameType::kVideoFrameKey,
                                            VideoFrameType::kVideoFrameKey}));

   // Insert delta frame.
   video_source_.IncomingCapturedFrame(CreateFrame(2, nullptr));
   WaitForEncodedFrame(2);
   EXPECT_THAT(fake_encoder_.LastFrameTypes(),
               ::testing::ElementsAreArray({VideoFrameType::kVideoFrameDelta,
                                            VideoFrameType::kVideoFrameDelta,
                                            VideoFrameType::kVideoFrameDelta}));

   // Request next frame be a key-frame.
   // Only first stream is configured to produce key-frame.
   video_stream_encoder_->SendKeyFrame();
   video_source_.IncomingCapturedFrame(CreateFrame(3, nullptr));
   WaitForEncodedFrame(3);

   // TODO(webrtc:10615): Map keyframe request to spatial layer. Currently
   // keyframe request on any layer triggers keyframe on all layers.
   EXPECT_THAT(fake_encoder_.LastFrameTypes(),
               ::testing::ElementsAreArray({VideoFrameType::kVideoFrameKey,
                                            VideoFrameType::kVideoFrameKey,
                                            VideoFrameType::kVideoFrameKey}));

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest, DoesNotRewriteH264BitstreamWithOptimalSps) {
   // SPS contains VUI with restrictions on the maximum number of reordered
   // pictures, there is no need to rewrite the bitstream to enable faster
   // decoding.
   ResetEncoder("H264", 1, 1, 1, false);

   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);
   video_stream_encoder_->WaitUntilTaskQueueIsIdle();

   fake_encoder_.SetEncodedImageData(
       EncodedImageBuffer::Create(kOptimalSps, sizeof(kOptimalSps)));

   video_source_.IncomingCapturedFrame(CreateFrame(1, nullptr));
   WaitForEncodedFrame(1);

   EXPECT_THAT(sink_.GetLastEncodedImageData(),
               testing::ElementsAreArray(kOptimalSps));

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest, RewritesH264BitstreamWithNonOptimalSps) {
   // SPS does not contain VUI, the bitstream is will be rewritten with added
   // VUI with restrictions on the maximum number of reordered pictures to
   // enable faster decoding.
   uint8_t original_sps[] = {0,    0,    0,    1,    H264::NaluType::kSps,
                             0x00, 0x00, 0x03, 0x03, 0xF4,
                             0x05, 0x03, 0xC7, 0xC0};
   ResetEncoder("H264", 1, 1, 1, false);

   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);
   video_stream_encoder_->WaitUntilTaskQueueIsIdle();

   fake_encoder_.SetEncodedImageData(
       EncodedImageBuffer::Create(original_sps, sizeof(original_sps)));

   video_source_.IncomingCapturedFrame(CreateFrame(1, nullptr));
   WaitForEncodedFrame(1);

   EXPECT_THAT(sink_.GetLastEncodedImageData(),
               testing::ElementsAreArray(kOptimalSps));

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest, CopiesVideoFrameMetadataAfterDownscale) {
   const int kFrameWidth = 1280;
   const int kFrameHeight = 720;
   const DataRate kTargetBitrate =
       DataRate::KilobitsPerSec(300);  // Too low for HD resolution.

   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);
   video_stream_encoder_->WaitUntilTaskQueueIsIdle();

   // Insert a first video frame. It should be dropped because of downscale in
   // resolution.
   int64_t timestamp_ms = CurrentTimeMs();
   VideoFrame frame = CreateFrame(timestamp_ms, kFrameWidth, kFrameHeight);
   frame.set_rotation(kVideoRotation_270);
   video_source_.IncomingCapturedFrame(frame);

   ExpectDroppedFrame();

   // Second frame is downscaled.
   timestamp_ms = CurrentTimeMs();
   frame = CreateFrame(timestamp_ms, kFrameWidth / 2, kFrameHeight / 2);
   frame.set_rotation(kVideoRotation_90);
   video_source_.IncomingCapturedFrame(frame);

   WaitForEncodedFrame(timestamp_ms);
   sink_.CheckLastFrameRotationMatches(kVideoRotation_90);

   // Insert another frame, also downscaled.
   timestamp_ms = CurrentTimeMs();
   frame = CreateFrame(timestamp_ms, kFrameWidth / 2, kFrameHeight / 2);
   frame.set_rotation(kVideoRotation_180);
   video_source_.IncomingCapturedFrame(frame);

   WaitForEncodedFrame(timestamp_ms);
   sink_.CheckLastFrameRotationMatches(kVideoRotation_180);

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest, BandwidthAllocationLowerBound) {
   const int kFrameWidth = 320;
   const int kFrameHeight = 180;

   // Initial rate.
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       /*target_bitrate=*/DataRate::KilobitsPerSec(300),
       /*stable_target_bitrate=*/DataRate::KilobitsPerSec(300),
       /*link_allocation=*/DataRate::KilobitsPerSec(300),
       /*fraction_lost=*/0,
       /*round_trip_time_ms=*/0,
       /*cwnd_reduce_ratio=*/0);

   // Insert a first video frame so that encoder gets configured.
   int64_t timestamp_ms = CurrentTimeMs();
   VideoFrame frame = CreateFrame(timestamp_ms, kFrameWidth, kFrameHeight);
   frame.set_rotation(kVideoRotation_270);
   video_source_.IncomingCapturedFrame(frame);
   WaitForEncodedFrame(timestamp_ms);

   // Set a target rate below the minimum allowed by the codec settings.
   VideoCodec codec_config = fake_encoder_.config();
   DataRate min_rate = DataRate::KilobitsPerSec(codec_config.minBitrate);
   DataRate target_rate = min_rate - DataRate::KilobitsPerSec(1);
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       /*target_bitrate=*/target_rate,
       /*stable_target_bitrate=*/target_rate,
       /*link_allocation=*/target_rate,
       /*fraction_lost=*/0,
       /*round_trip_time_ms=*/0,
       /*cwnd_reduce_ratio=*/0);
   video_stream_encoder_->WaitUntilTaskQueueIsIdle();

   // Target bitrate and bandwidth allocation should both be capped at min_rate.
   auto rate_settings = fake_encoder_.GetAndResetLastRateControlSettings();
   ASSERT_TRUE(rate_settings.has_value());
   DataRate allocation_sum =
       DataRate::BitsPerSec(rate_settings->bitrate.get_sum_bps());
   EXPECT_EQ(min_rate, allocation_sum);
   EXPECT_EQ(rate_settings->bandwidth_allocation, min_rate);

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest, EncoderRatesPropagatedOnReconfigure) {
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);
   // Capture a frame and wait for it to synchronize with the encoder thread.
   int64_t timestamp_ms = CurrentTimeMs();
   video_source_.IncomingCapturedFrame(CreateFrame(timestamp_ms, nullptr));
   WaitForEncodedFrame(1);

   auto prev_rate_settings = fake_encoder_.GetAndResetLastRateControlSettings();
   ASSERT_TRUE(prev_rate_settings.has_value());
   EXPECT_EQ(static_cast<int>(prev_rate_settings->framerate_fps),
             kDefaultFramerate);

   // Send 1s of video to ensure the framerate is stable at kDefaultFramerate.
   for (int i = 0; i < 2 * kDefaultFramerate; i++) {
     timestamp_ms += 1000 / kDefaultFramerate;
     video_source_.IncomingCapturedFrame(CreateFrame(timestamp_ms, nullptr));
     WaitForEncodedFrame(timestamp_ms);
   }
   EXPECT_EQ(static_cast<int>(fake_encoder_.GetLastFramerate()),
             kDefaultFramerate);
   // Capture larger frame to trigger a reconfigure.
   codec_height_ *= 2;
   codec_width_ *= 2;
   timestamp_ms += 1000 / kDefaultFramerate;
   video_source_.IncomingCapturedFrame(CreateFrame(timestamp_ms, nullptr));
   WaitForEncodedFrame(timestamp_ms);

   EXPECT_EQ(2, sink_.number_of_reconfigurations());
   auto current_rate_settings =
       fake_encoder_.GetAndResetLastRateControlSettings();
   // Ensure we have actually reconfigured twice
   // The rate settings should have been set again even though
   // they haven't changed.
   ASSERT_TRUE(current_rate_settings.has_value());
   EXPECT_EQ(prev_rate_settings, current_rate_settings);

   video_stream_encoder_->Stop();
 }

 struct MockEncoderSwitchRequestCallback : public EncoderSwitchRequestCallback {
   MOCK_METHOD(void, RequestEncoderFallback, (), (override));
   MOCK_METHOD(void,
               RequestEncoderSwitch,
               (const webrtc::SdpVideoFormat& format,
                bool allow_default_fallback),
               (override));
 };

 TEST_F(VideoStreamEncoderTest, EncoderSelectorCurrentEncoderIsSignaled) {
   constexpr int kDontCare = 100;
   StrictMock<MockEncoderSelector> encoder_selector;
   auto encoder_factory = std::make_unique<test::VideoEncoderProxyFactory>(
       &fake_encoder_, &encoder_selector);
   video_send_config_.encoder_settings.encoder_factory = encoder_factory.get();

   // Reset encoder for new configuration to take effect.
   ConfigureEncoder(video_encoder_config_.Copy());

   EXPECT_CALL(encoder_selector, OnCurrentEncoder);

   video_source_.IncomingCapturedFrame(
       CreateFrame(kDontCare, kDontCare, kDontCare));
   AdvanceTime(TimeDelta::Zero());
   video_stream_encoder_->Stop();

   // The encoders produced by the VideoEncoderProxyFactory have a pointer back
   // to it's factory, so in order for the encoder instance in the
   // `video_stream_encoder_` to be destroyed before the `encoder_factory` we
   // reset the `video_stream_encoder_` here.
   video_stream_encoder_.reset();
 }

 TEST_F(VideoStreamEncoderTest, EncoderSelectorBitrateSwitch) {
   constexpr int kDontCare = 100;

   NiceMock<MockEncoderSelector> encoder_selector;
   StrictMock<MockEncoderSwitchRequestCallback> switch_callback;
   video_send_config_.encoder_settings.encoder_switch_request_callback =
       &switch_callback;
   auto encoder_factory = std::make_unique<test::VideoEncoderProxyFactory>(
       &fake_encoder_, &encoder_selector);
   video_send_config_.encoder_settings.encoder_factory = encoder_factory.get();

   // Reset encoder for new configuration to take effect.
   ConfigureEncoder(video_encoder_config_.Copy());

   ON_CALL(encoder_selector, OnAvailableBitrate)
       .WillByDefault(Return(SdpVideoFormat("AV1")));
   EXPECT_CALL(switch_callback,
               RequestEncoderSwitch(Field(&SdpVideoFormat::name, "AV1"),
                                    /*allow_default_fallback=*/false));

   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       /*target_bitrate=*/DataRate::KilobitsPerSec(50),
       /*stable_target_bitrate=*/DataRate::KilobitsPerSec(kDontCare),
       /*link_allocation=*/DataRate::KilobitsPerSec(kDontCare),
       /*fraction_lost=*/0,
       /*round_trip_time_ms=*/0,
       /*cwnd_reduce_ratio=*/0);
   AdvanceTime(TimeDelta::Zero());

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest, EncoderSelectorResolutionSwitch) {
   NiceMock<MockEncoderSelector> encoder_selector;
   StrictMock<MockEncoderSwitchRequestCallback> switch_callback;
   video_send_config_.encoder_settings.encoder_switch_request_callback =
       &switch_callback;
   auto encoder_factory = std::make_unique<test::VideoEncoderProxyFactory>(
       &fake_encoder_, &encoder_selector);
   video_send_config_.encoder_settings.encoder_factory = encoder_factory.get();

   // Reset encoder for new configuration to take effect.
   ConfigureEncoder(video_encoder_config_.Copy());

   EXPECT_CALL(encoder_selector, OnResolutionChange(RenderResolution(640, 480)))
       .WillOnce(Return(absl::nullopt));
   EXPECT_CALL(encoder_selector, OnResolutionChange(RenderResolution(320, 240)))
       .WillOnce(Return(SdpVideoFormat("AV1")));
   EXPECT_CALL(switch_callback,
               RequestEncoderSwitch(Field(&SdpVideoFormat::name, "AV1"),
                                    /*allow_default_fallback=*/false));

   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       /*target_bitrate=*/DataRate::KilobitsPerSec(800),
       /*stable_target_bitrate=*/DataRate::KilobitsPerSec(1000),
       /*link_allocation=*/DataRate::KilobitsPerSec(1000),
       /*fraction_lost=*/0,
       /*round_trip_time_ms=*/0,
       /*cwnd_reduce_ratio=*/0);

   video_source_.IncomingCapturedFrame(CreateFrame(1, 640, 480));
   video_source_.IncomingCapturedFrame(CreateFrame(2, 640, 480));
   video_source_.IncomingCapturedFrame(CreateFrame(3, 320, 240));

   AdvanceTime(TimeDelta::Zero());

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest, EncoderSelectorBrokenEncoderSwitch) {
   constexpr int kSufficientBitrateToNotDrop = 1000;
   constexpr int kDontCare = 100;

   NiceMock<MockVideoEncoder> video_encoder;
   NiceMock<MockEncoderSelector> encoder_selector;
   StrictMock<MockEncoderSwitchRequestCallback> switch_callback;
   video_send_config_.encoder_settings.encoder_switch_request_callback =
       &switch_callback;
   auto encoder_factory = std::make_unique<test::VideoEncoderProxyFactory>(
       &video_encoder, &encoder_selector);
   video_send_config_.encoder_settings.encoder_factory = encoder_factory.get();

   // Reset encoder for new configuration to take effect.
   ConfigureEncoder(video_encoder_config_.Copy());

   // The VideoStreamEncoder needs some bitrate before it can start encoding,
   // setting some bitrate so that subsequent calls to WaitForEncodedFrame does
   // not fail.
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       /*target_bitrate=*/DataRate::KilobitsPerSec(kSufficientBitrateToNotDrop),
       /*stable_target_bitrate=*/
       DataRate::KilobitsPerSec(kSufficientBitrateToNotDrop),
       /*link_allocation=*/DataRate::KilobitsPerSec(kSufficientBitrateToNotDrop),
       /*fraction_lost=*/0,
       /*round_trip_time_ms=*/0,
       /*cwnd_reduce_ratio=*/0);

   ON_CALL(video_encoder, Encode)
       .WillByDefault(Return(WEBRTC_VIDEO_CODEC_ENCODER_FAILURE));
   ON_CALL(encoder_selector, OnEncoderBroken)
       .WillByDefault(Return(SdpVideoFormat("AV2")));

   rtc::Event encode_attempted;
   EXPECT_CALL(switch_callback,
               RequestEncoderSwitch(Field(&SdpVideoFormat::name, "AV2"),
                                    /*allow_default_fallback=*/true))
       .WillOnce([&encode_attempted]() { encode_attempted.Set(); });

   video_source_.IncomingCapturedFrame(CreateFrame(1, kDontCare, kDontCare));
   encode_attempted.Wait(TimeDelta::Seconds(3));

   AdvanceTime(TimeDelta::Zero());

   video_stream_encoder_->Stop();

   // The encoders produced by the VideoEncoderProxyFactory have a pointer back
   // to it's factory, so in order for the encoder instance in the
   // `video_stream_encoder_` to be destroyed before the `encoder_factory` we
   // reset the `video_stream_encoder_` here.
   video_stream_encoder_.reset();
 }

 TEST_F(VideoStreamEncoderTest, SwitchEncoderOnInitFailureWithEncoderSelector) {
   NiceMock<MockVideoEncoder> video_encoder;
   NiceMock<MockEncoderSelector> encoder_selector;
   StrictMock<MockEncoderSwitchRequestCallback> switch_callback;
   video_send_config_.encoder_settings.encoder_switch_request_callback =
       &switch_callback;
   auto encoder_factory = std::make_unique<test::VideoEncoderProxyFactory>(
       &video_encoder, &encoder_selector);
   video_send_config_.encoder_settings.encoder_factory = encoder_factory.get();

   // Reset encoder for new configuration to take effect.
   ConfigureEncoder(video_encoder_config_.Copy());

   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, /*fraction_lost=*/0,
       /*round_trip_time_ms=*/0,
       /*cwnd_reduce_ratio=*/0);
   ASSERT_EQ(0, sink_.number_of_reconfigurations());

   ON_CALL(video_encoder, InitEncode(_, _))
       .WillByDefault(Return(WEBRTC_VIDEO_CODEC_ENCODER_FAILURE));
   ON_CALL(encoder_selector, OnEncoderBroken)
       .WillByDefault(Return(SdpVideoFormat("AV2")));

   rtc::Event encode_attempted;
   EXPECT_CALL(switch_callback,
               RequestEncoderSwitch(Field(&SdpVideoFormat::name, "AV2"),
                                    /*allow_default_fallback=*/true))
       .WillOnce([&encode_attempted]() { encode_attempted.Set(); });

   video_source_.IncomingCapturedFrame(CreateFrame(1, nullptr));
   encode_attempted.Wait(TimeDelta::Seconds(3));

   AdvanceTime(TimeDelta::Zero());

   video_stream_encoder_->Stop();

   // The encoders produced by the VideoEncoderProxyFactory have a pointer back
   // to it's factory, so in order for the encoder instance in the
   // `video_stream_encoder_` to be destroyed before the `encoder_factory` we
   // reset the `video_stream_encoder_` here.
   video_stream_encoder_.reset();
 }

 TEST_F(VideoStreamEncoderTest,
        SwitchEncoderOnInitFailureWithoutEncoderSelector) {
   NiceMock<MockVideoEncoder> video_encoder;
   StrictMock<MockEncoderSwitchRequestCallback> switch_callback;
   video_send_config_.encoder_settings.encoder_switch_request_callback =
       &switch_callback;
   auto encoder_factory = std::make_unique<test::VideoEncoderProxyFactory>(
       &video_encoder, /*encoder_selector=*/nullptr);
   video_send_config_.encoder_settings.encoder_factory = encoder_factory.get();

   // Reset encoder for new configuration to take effect.
   ConfigureEncoder(video_encoder_config_.Copy());

   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, /*fraction_lost=*/0,
       /*round_trip_time_ms=*/0,
       /*cwnd_reduce_ratio=*/0);
   ASSERT_EQ(0, sink_.number_of_reconfigurations());

   ON_CALL(video_encoder, InitEncode(_, _))
       .WillByDefault(Return(WEBRTC_VIDEO_CODEC_ENCODER_FAILURE));

   rtc::Event encode_attempted;
   EXPECT_CALL(switch_callback,
               RequestEncoderSwitch(Field(&SdpVideoFormat::name, "VP8"),
                                    /*allow_default_fallback=*/true))
       .WillOnce([&encode_attempted]() { encode_attempted.Set(); });

   video_source_.IncomingCapturedFrame(CreateFrame(1, nullptr));
   encode_attempted.Wait(TimeDelta::Seconds(3));

   AdvanceTime(TimeDelta::Zero());

   video_stream_encoder_->Stop();

   // The encoders produced by the VideoEncoderProxyFactory have a pointer back
   // to it's factory, so in order for the encoder instance in the
   // `video_stream_encoder_` to be destroyed before the `encoder_factory` we
   // reset the `video_stream_encoder_` here.
   video_stream_encoder_.reset();
 }

 TEST_F(VideoStreamEncoderTest, NullEncoderReturnSwitch) {
   // As a variant of EncoderSelectorBrokenEncoderSwitch, when a null
   // VideoEncoder is passed in encoder_factory, it checks whether
   // Codec Switch occurs without a crash.
   constexpr int kSufficientBitrateToNotDrop = 1000;
   constexpr int kDontCare = 100;

   NiceMock<MockEncoderSelector> encoder_selector;
   StrictMock<MockEncoderSwitchRequestCallback> switch_callback;
   video_send_config_.encoder_settings.encoder_switch_request_callback =
       &switch_callback;
   auto encoder_factory =
       std::make_unique<test::VideoEncoderNullableProxyFactory>(
           /*encoder=*/nullptr, &encoder_selector);
   video_send_config_.encoder_settings.encoder_factory = encoder_factory.get();

   // Reset encoder for new configuration to take effect.
   ConfigureEncoder(video_encoder_config_.Copy());
   // The VideoStreamEncoder needs some bitrate before it can start encoding,
   // setting some bitrate so that subsequent calls to WaitForEncodedFrame does
   // not fail.
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       /*target_bitrate=*/DataRate::KilobitsPerSec(kSufficientBitrateToNotDrop),
       /*stable_target_bitrate=*/
       DataRate::KilobitsPerSec(kSufficientBitrateToNotDrop),
       /*link_allocation=*/DataRate::KilobitsPerSec(kSufficientBitrateToNotDrop),
       /*fraction_lost=*/0,
       /*round_trip_time_ms=*/0,
       /*cwnd_reduce_ratio=*/0);
   ON_CALL(encoder_selector, OnEncoderBroken)
       .WillByDefault(Return(SdpVideoFormat("AV2")));
   rtc::Event encode_attempted;
   EXPECT_CALL(switch_callback,
               RequestEncoderSwitch(Field(&SdpVideoFormat::name, "AV2"),
                                    /*allow_default_fallback=*/_))
       .WillOnce([&encode_attempted]() { encode_attempted.Set(); });

   video_source_.IncomingCapturedFrame(CreateFrame(1, kDontCare, kDontCare));
   encode_attempted.Wait(TimeDelta::Seconds(3));

   AdvanceTime(TimeDelta::Zero());

   video_stream_encoder_->Stop();

   // The encoders produced by the VideoEncoderProxyFactory have a pointer back
   // to it's factory, so in order for the encoder instance in the
   // `video_stream_encoder_` to be destroyed before the `encoder_factory` we
   // reset the `video_stream_encoder_` here.
   video_stream_encoder_.reset();
 }

 TEST_F(VideoStreamEncoderTest,
        AllocationPropagatedToEncoderWhenTargetRateChanged) {
   const int kFrameWidth = 320;
   const int kFrameHeight = 180;

   // Set initial rate.
   auto rate = DataRate::KilobitsPerSec(100);
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       /*target_bitrate=*/rate,
       /*stable_target_bitrate=*/rate,
       /*link_allocation=*/rate,
       /*fraction_lost=*/0,
       /*round_trip_time_ms=*/0,
       /*cwnd_reduce_ratio=*/0);

   // Insert a first video frame so that encoder gets configured.
   int64_t timestamp_ms = CurrentTimeMs();
   VideoFrame frame = CreateFrame(timestamp_ms, kFrameWidth, kFrameHeight);
   frame.set_rotation(kVideoRotation_270);
   video_source_.IncomingCapturedFrame(frame);
   WaitForEncodedFrame(timestamp_ms);
   EXPECT_EQ(1, fake_encoder_.GetNumSetRates());

   // Change of target bitrate propagates to the encoder.
   auto new_stable_rate = rate - DataRate::KilobitsPerSec(5);
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       /*target_bitrate=*/new_stable_rate,
       /*stable_target_bitrate=*/new_stable_rate,
       /*link_allocation=*/rate,
       /*fraction_lost=*/0,
       /*round_trip_time_ms=*/0,
       /*cwnd_reduce_ratio=*/0);
   video_stream_encoder_->WaitUntilTaskQueueIsIdle();
   EXPECT_EQ(2, fake_encoder_.GetNumSetRates());
   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest,
        AllocationNotPropagatedToEncoderWhenTargetRateUnchanged) {
   const int kFrameWidth = 320;
   const int kFrameHeight = 180;

   // Set initial rate.
   auto rate = DataRate::KilobitsPerSec(100);
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       /*target_bitrate=*/rate,
       /*stable_target_bitrate=*/rate,
       /*link_allocation=*/rate,
       /*fraction_lost=*/0,
       /*round_trip_time_ms=*/0,
       /*cwnd_reduce_ratio=*/0);

   // Insert a first video frame so that encoder gets configured.
   int64_t timestamp_ms = CurrentTimeMs();
   VideoFrame frame = CreateFrame(timestamp_ms, kFrameWidth, kFrameHeight);
   frame.set_rotation(kVideoRotation_270);
   video_source_.IncomingCapturedFrame(frame);
   WaitForEncodedFrame(timestamp_ms);
   EXPECT_EQ(1, fake_encoder_.GetNumSetRates());

   // Set a higher target rate without changing the link_allocation. Should not
   // reset encoder's rate.
   auto new_stable_rate = rate - DataRate::KilobitsPerSec(5);
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       /*target_bitrate=*/rate,
       /*stable_target_bitrate=*/new_stable_rate,
       /*link_allocation=*/rate,
       /*fraction_lost=*/0,
       /*round_trip_time_ms=*/0,
       /*cwnd_reduce_ratio=*/0);
   video_stream_encoder_->WaitUntilTaskQueueIsIdle();
   EXPECT_EQ(1, fake_encoder_.GetNumSetRates());
   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest, AutomaticAnimationDetection) {
   test::ScopedKeyValueConfig field_trials(
       field_trials_,
       "WebRTC-AutomaticAnimationDetectionScreenshare/"
       "enabled:true,min_fps:20,min_duration_ms:1000,min_area_ratio:0.8/");
   const int kFramerateFps = 30;
   const int kWidth = 1920;
   const int kHeight = 1080;
   const int kNumFrames = 2 * kFramerateFps;  // >1 seconds of frames.
   // Works on screenshare mode.
   ResetEncoder("VP8", 1, 1, 1, /*screenshare*/ true);
   // We rely on the automatic resolution adaptation, but we handle framerate
   // adaptation manually by mocking the stats proxy.
   video_source_.set_adaptation_enabled(true);

   // BALANCED degradation preference is required for this feature.
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);
   video_stream_encoder_->SetSource(&video_source_,
                                    webrtc::DegradationPreference::BALANCED);
   EXPECT_THAT(video_source_.sink_wants(), UnlimitedSinkWants());

   VideoFrame frame = CreateFrame(1, kWidth, kHeight);
   frame.set_update_rect(VideoFrame::UpdateRect{0, 0, kWidth, kHeight});

   // Pass enough frames with the full update to trigger animation detection.
   for (int i = 0; i < kNumFrames; ++i) {
     int64_t timestamp_ms = CurrentTimeMs();
     frame.set_ntp_time_ms(timestamp_ms);
     frame.set_timestamp_us(timestamp_ms * 1000);
     video_source_.IncomingCapturedFrame(frame);
     WaitForEncodedFrame(timestamp_ms);
   }

   // Resolution should be limited.
   rtc::VideoSinkWants expected;
   expected.max_framerate_fps = kFramerateFps;
   expected.max_pixel_count = 1280 * 720 + 1;
   EXPECT_THAT(video_source_.sink_wants(), FpsEqResolutionLt(expected));

   // Pass one frame with no known update.
   //  Resolution cap should be removed immediately.
   int64_t timestamp_ms = CurrentTimeMs();
   frame.set_ntp_time_ms(timestamp_ms);
   frame.set_timestamp_us(timestamp_ms * 1000);
   frame.clear_update_rect();

   video_source_.IncomingCapturedFrame(frame);
   WaitForEncodedFrame(timestamp_ms);

   // Resolution should be unlimited now.
   EXPECT_THAT(video_source_.sink_wants(),
               FpsMatchesResolutionMax(Eq(kFramerateFps)));

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest, ConfiguresVp9SvcAtOddResolutions) {
   const int kWidth = 720;  // 540p adapted down.
   const int kHeight = 405;
   const int kNumFrames = 3;
   // Works on screenshare mode.
   ResetEncoder("VP9", /*num_streams=*/1, /*num_temporal_layers=*/1,
                /*num_spatial_layers=*/2, /*screenshare=*/true);

   video_source_.set_adaptation_enabled(true);

   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);

   VideoFrame frame = CreateFrame(1, kWidth, kHeight);

   // Pass enough frames with the full update to trigger animation detection.
   for (int i = 0; i < kNumFrames; ++i) {
     int64_t timestamp_ms = CurrentTimeMs();
     frame.set_ntp_time_ms(timestamp_ms);
     frame.set_timestamp_us(timestamp_ms * 1000);
     video_source_.IncomingCapturedFrame(frame);
     WaitForEncodedFrame(timestamp_ms);
   }

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest, EncoderResetAccordingToParameterChange) {
   const float downscale_factors[] = {4.0, 2.0, 1.0};
   const int number_layers =
       sizeof(downscale_factors) / sizeof(downscale_factors[0]);
   VideoEncoderConfig config;
   webrtc::VideoEncoder::EncoderInfo encoder_info;
   test::FillEncoderConfiguration(kVideoCodecVP8, number_layers, &config);
   for (int i = 0; i < number_layers; ++i) {
     config.simulcast_layers[i].scale_resolution_down_by = downscale_factors[i];
     config.simulcast_layers[i].active = true;
   }
   config.video_stream_factory =
       rtc::make_ref_counted<cricket::EncoderStreamFactory>(
           "VP8", /*max qp*/ 56, /*screencast*/ false,
           /*screenshare enabled*/ false, encoder_info);
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kSimulcastTargetBitrate, kSimulcastTargetBitrate, kSimulcastTargetBitrate,
       0, 0, 0);

   // First initialization.
   // Encoder should be initialized. Next frame should be key frame.
   video_stream_encoder_->ConfigureEncoder(config.Copy(), kMaxPayloadLength);
   sink_.SetNumExpectedLayers(number_layers);
   int64_t timestamp_ms = kFrameIntervalMs;
   video_source_.IncomingCapturedFrame(CreateFrame(timestamp_ms, 1280, 720));
   WaitForEncodedFrame(timestamp_ms);
   EXPECT_EQ(1, fake_encoder_.GetNumInitializations());
   EXPECT_THAT(fake_encoder_.LastFrameTypes(),
               ::testing::ElementsAreArray({VideoFrameType::kVideoFrameKey,
                                            VideoFrameType::kVideoFrameKey,
                                            VideoFrameType::kVideoFrameKey}));

   // Disable top layer.
   // Encoder shouldn't be re-initialized. Next frame should be delta frame.
   config.simulcast_layers[number_layers - 1].active = false;
   video_stream_encoder_->ConfigureEncoder(config.Copy(), kMaxPayloadLength);
   sink_.SetNumExpectedLayers(number_layers - 1);
   timestamp_ms += kFrameIntervalMs;
   video_source_.IncomingCapturedFrame(CreateFrame(timestamp_ms, 1280, 720));
   WaitForEncodedFrame(timestamp_ms);
   EXPECT_EQ(1, fake_encoder_.GetNumInitializations());
   EXPECT_THAT(fake_encoder_.LastFrameTypes(),
               ::testing::ElementsAreArray({VideoFrameType::kVideoFrameDelta,
                                            VideoFrameType::kVideoFrameDelta,
                                            VideoFrameType::kVideoFrameDelta}));

   // Re-enable top layer.
   // Encoder should be re-initialized. Next frame should be key frame.
   config.simulcast_layers[number_layers - 1].active = true;
   video_stream_encoder_->ConfigureEncoder(config.Copy(), kMaxPayloadLength);
   sink_.SetNumExpectedLayers(number_layers);
   timestamp_ms += kFrameIntervalMs;
   video_source_.IncomingCapturedFrame(CreateFrame(timestamp_ms, 1280, 720));
   WaitForEncodedFrame(timestamp_ms);
   EXPECT_EQ(2, fake_encoder_.GetNumInitializations());
   EXPECT_THAT(fake_encoder_.LastFrameTypes(),
               ::testing::ElementsAreArray({VideoFrameType::kVideoFrameKey,
                                            VideoFrameType::kVideoFrameKey,
                                            VideoFrameType::kVideoFrameKey}));

   // Top layer max rate change.
   // Encoder shouldn't be re-initialized. Next frame should be delta frame.
   config.simulcast_layers[number_layers - 1].max_bitrate_bps -= 100;
   video_stream_encoder_->ConfigureEncoder(config.Copy(), kMaxPayloadLength);
   sink_.SetNumExpectedLayers(number_layers);
   timestamp_ms += kFrameIntervalMs;
   video_source_.IncomingCapturedFrame(CreateFrame(timestamp_ms, 1280, 720));
   WaitForEncodedFrame(timestamp_ms);
   EXPECT_EQ(2, fake_encoder_.GetNumInitializations());
   EXPECT_THAT(fake_encoder_.LastFrameTypes(),
               ::testing::ElementsAreArray({VideoFrameType::kVideoFrameDelta,
                                            VideoFrameType::kVideoFrameDelta,
                                            VideoFrameType::kVideoFrameDelta}));

   // Top layer resolution change.
   // Encoder should be re-initialized. Next frame should be key frame.
   config.simulcast_layers[number_layers - 1].scale_resolution_down_by += 0.1;
   video_stream_encoder_->ConfigureEncoder(config.Copy(), kMaxPayloadLength);
   sink_.SetNumExpectedLayers(number_layers);
   timestamp_ms += kFrameIntervalMs;
   video_source_.IncomingCapturedFrame(CreateFrame(timestamp_ms, 1280, 720));
   WaitForEncodedFrame(timestamp_ms);
   EXPECT_EQ(3, fake_encoder_.GetNumInitializations());
   EXPECT_THAT(fake_encoder_.LastFrameTypes(),
               ::testing::ElementsAreArray({VideoFrameType::kVideoFrameKey,
                                            VideoFrameType::kVideoFrameKey,
                                            VideoFrameType::kVideoFrameKey}));
   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest, EncoderResolutionsExposedInSinglecast) {
   const int kFrameWidth = 1280;
   const int kFrameHeight = 720;

   SetUp();
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);

   // Capturing a frame should reconfigure the encoder and expose the encoder
   // resolution, which is the same as the input frame.
   int64_t timestamp_ms = kFrameIntervalMs;
   video_source_.IncomingCapturedFrame(
       CreateFrame(timestamp_ms, kFrameWidth, kFrameHeight));
   WaitForEncodedFrame(timestamp_ms);
   video_stream_encoder_->WaitUntilTaskQueueIsIdle();
   EXPECT_THAT(video_source_.sink_wants().resolutions,
               ::testing::ElementsAreArray(
                   {rtc::VideoSinkWants::FrameSize(kFrameWidth, kFrameHeight)}));

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest, EncoderResolutionsExposedInSimulcast) {
   // Pick downscale factors such that we never encode at full resolution - this
   // is an interesting use case. The frame resolution influences the encoder
   // resolutions, but if no layer has `scale_resolution_down_by` == 1 then the
   // encoder should not ask for the frame resolution. This allows video frames
   // to have the appearence of one resolution but optimize its internal buffers
   // for what is actually encoded.
   const size_t kNumSimulcastLayers = 3u;
   const float kDownscaleFactors[] = {8.0, 4.0, 2.0};
   const int kFrameWidth = 1280;
   const int kFrameHeight = 720;
   const rtc::VideoSinkWants::FrameSize kLayer0Size(
       kFrameWidth / kDownscaleFactors[0], kFrameHeight / kDownscaleFactors[0]);
   const rtc::VideoSinkWants::FrameSize kLayer1Size(
       kFrameWidth / kDownscaleFactors[1], kFrameHeight / kDownscaleFactors[1]);
   const rtc::VideoSinkWants::FrameSize kLayer2Size(
       kFrameWidth / kDownscaleFactors[2], kFrameHeight / kDownscaleFactors[2]);

   VideoEncoderConfig config;
   webrtc::VideoEncoder::EncoderInfo encoder_info;
   test::FillEncoderConfiguration(kVideoCodecVP8, kNumSimulcastLayers, &config);
   for (size_t i = 0; i < kNumSimulcastLayers; ++i) {
     config.simulcast_layers[i].scale_resolution_down_by = kDownscaleFactors[i];
     config.simulcast_layers[i].active = true;
   }
   config.video_stream_factory =
       rtc::make_ref_counted<cricket::EncoderStreamFactory>(
           "VP8", /*max qp*/ 56, /*screencast*/ false,
           /*screenshare enabled*/ false, encoder_info);
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kSimulcastTargetBitrate, kSimulcastTargetBitrate, kSimulcastTargetBitrate,
       0, 0, 0);

   // Capture a frame with all layers active.
   int64_t timestamp_ms = kFrameIntervalMs;
   sink_.SetNumExpectedLayers(kNumSimulcastLayers);
   video_stream_encoder_->ConfigureEncoder(config.Copy(), kMaxPayloadLength);
   video_source_.IncomingCapturedFrame(
       CreateFrame(timestamp_ms, kFrameWidth, kFrameHeight));
   WaitForEncodedFrame(timestamp_ms);
   // Expect encoded resolutions to match the expected simulcast layers.
   video_stream_encoder_->WaitUntilTaskQueueIsIdle();
   EXPECT_THAT(
       video_source_.sink_wants().resolutions,
       ::testing::ElementsAreArray({kLayer0Size, kLayer1Size, kLayer2Size}));

   // Capture a frame with one of the layers inactive.
   timestamp_ms += kFrameIntervalMs;
   config.simulcast_layers[2].active = false;
   sink_.SetNumExpectedLayers(kNumSimulcastLayers - 1);
   video_stream_encoder_->ConfigureEncoder(config.Copy(), kMaxPayloadLength);
   video_source_.IncomingCapturedFrame(
       CreateFrame(timestamp_ms, kFrameWidth, kFrameHeight));
   WaitForEncodedFrame(timestamp_ms);

   // Expect encoded resolutions to match the expected simulcast layers.
   video_stream_encoder_->WaitUntilTaskQueueIsIdle();
   EXPECT_THAT(video_source_.sink_wants().resolutions,
               ::testing::ElementsAreArray({kLayer0Size, kLayer1Size}));

   // Capture a frame with all but one layer turned off.
   timestamp_ms += kFrameIntervalMs;
   config.simulcast_layers[1].active = false;
   sink_.SetNumExpectedLayers(kNumSimulcastLayers - 2);
   video_stream_encoder_->ConfigureEncoder(config.Copy(), kMaxPayloadLength);
   video_source_.IncomingCapturedFrame(
       CreateFrame(timestamp_ms, kFrameWidth, kFrameHeight));
   WaitForEncodedFrame(timestamp_ms);

   // Expect encoded resolutions to match the expected simulcast layers.
   video_stream_encoder_->WaitUntilTaskQueueIsIdle();
   EXPECT_THAT(video_source_.sink_wants().resolutions,
               ::testing::ElementsAreArray({kLayer0Size}));

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest, QpPresent_QpKept) {
   ResetEncoder("VP8", 1, 1, 1, false);

   // Force encoder reconfig.
   video_source_.IncomingCapturedFrame(
       CreateFrame(1, codec_width_, codec_height_));
   video_stream_encoder_->WaitUntilTaskQueueIsIdle();

   // Set QP on encoded frame and pass the frame to encode complete callback.
   // Since QP is present QP parsing won't be triggered and the original value
   // should be kept.
   EncodedImage encoded_image;
   encoded_image.qp_ = 123;
   encoded_image.SetEncodedData(EncodedImageBuffer::Create(
       kCodedFrameVp8Qp25, sizeof(kCodedFrameVp8Qp25)));
   CodecSpecificInfo codec_info;
   codec_info.codecType = kVideoCodecVP8;
   fake_encoder_.InjectEncodedImage(encoded_image, &codec_info);
   EXPECT_TRUE(sink_.WaitForFrame(kDefaultTimeout));
   EXPECT_EQ(sink_.GetLastEncodedImage().qp_, 123);
   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest, QpAbsent_QpParsed) {
   ResetEncoder("VP8", 1, 1, 1, false);

   // Force encoder reconfig.
   video_source_.IncomingCapturedFrame(
       CreateFrame(1, codec_width_, codec_height_));
   video_stream_encoder_->WaitUntilTaskQueueIsIdle();

   // Pass an encoded frame without QP to encode complete callback. QP should be
   // parsed and set.
   EncodedImage encoded_image;
   encoded_image.qp_ = -1;
   encoded_image.SetEncodedData(EncodedImageBuffer::Create(
       kCodedFrameVp8Qp25, sizeof(kCodedFrameVp8Qp25)));
   CodecSpecificInfo codec_info;
   codec_info.codecType = kVideoCodecVP8;
   fake_encoder_.InjectEncodedImage(encoded_image, &codec_info);
   EXPECT_TRUE(sink_.WaitForFrame(kDefaultTimeout));
   EXPECT_EQ(sink_.GetLastEncodedImage().qp_, 25);
   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest, QpAbsentParsingDisabled_QpAbsent) {
   webrtc::test::ScopedKeyValueConfig field_trials(
       field_trials_, "WebRTC-QpParsingKillSwitch/Enabled/");

   ResetEncoder("VP8", 1, 1, 1, false);

   // Force encoder reconfig.
   video_source_.IncomingCapturedFrame(
       CreateFrame(1, codec_width_, codec_height_));
   video_stream_encoder_->WaitUntilTaskQueueIsIdle();

   EncodedImage encoded_image;
   encoded_image.qp_ = -1;
   encoded_image.SetEncodedData(EncodedImageBuffer::Create(
       kCodedFrameVp8Qp25, sizeof(kCodedFrameVp8Qp25)));
   CodecSpecificInfo codec_info;
   codec_info.codecType = kVideoCodecVP8;
   fake_encoder_.InjectEncodedImage(encoded_image, &codec_info);
   EXPECT_TRUE(sink_.WaitForFrame(kDefaultTimeout));
   EXPECT_EQ(sink_.GetLastEncodedImage().qp_, -1);
   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest,
        QualityScalingNotAllowed_QualityScalingDisabled) {
   VideoEncoderConfig video_encoder_config = video_encoder_config_.Copy();

   // Disable scaling settings in encoder info.
   fake_encoder_.SetQualityScaling(false);
   // Disable quality scaling in encoder config.
   video_encoder_config.is_quality_scaling_allowed = false;
   ConfigureEncoder(std::move(video_encoder_config));

   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);

   test::FrameForwarder source;
   video_stream_encoder_->SetSource(
       &source, webrtc::DegradationPreference::MAINTAIN_FRAMERATE);
   EXPECT_THAT(source.sink_wants(), UnlimitedSinkWants());
   EXPECT_FALSE(stats_proxy_->GetStats().bw_limited_resolution);

   source.IncomingCapturedFrame(CreateFrame(1, 1280, 720));
   WaitForEncodedFrame(1);
   video_stream_encoder_->TriggerQualityLow();
   EXPECT_FALSE(stats_proxy_->GetStats().bw_limited_resolution);

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest, QualityScalingNotAllowed_IsQpTrustedSetTrue) {
   VideoEncoderConfig video_encoder_config = video_encoder_config_.Copy();

   // Disable scaling settings in encoder info.
   fake_encoder_.SetQualityScaling(false);
   // Set QP trusted in encoder info.
   fake_encoder_.SetIsQpTrusted(true);
   // Enable quality scaling in encoder config.
   video_encoder_config.is_quality_scaling_allowed = false;
   ConfigureEncoder(std::move(video_encoder_config));

   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);

   test::FrameForwarder source;
   video_stream_encoder_->SetSource(
       &source, webrtc::DegradationPreference::MAINTAIN_FRAMERATE);
   EXPECT_THAT(source.sink_wants(), UnlimitedSinkWants());
   EXPECT_FALSE(stats_proxy_->GetStats().bw_limited_resolution);

   source.IncomingCapturedFrame(CreateFrame(1, 1280, 720));
   WaitForEncodedFrame(1);
   video_stream_encoder_->TriggerQualityLow();
   EXPECT_FALSE(stats_proxy_->GetStats().bw_limited_resolution);

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest,
        QualityScalingNotAllowedAndQPIsTrusted_BandwidthScalerDisable) {
   VideoEncoderConfig video_encoder_config = video_encoder_config_.Copy();

   // Disable scaling settings in encoder info.
   fake_encoder_.SetQualityScaling(false);
   // Set QP trusted in encoder info.
   fake_encoder_.SetIsQpTrusted(true);
   // Enable quality scaling in encoder config.
   video_encoder_config.is_quality_scaling_allowed = false;
   ConfigureEncoder(std::move(video_encoder_config));

   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);

   test::FrameForwarder source;
   video_stream_encoder_->SetSource(
       &source, webrtc::DegradationPreference::MAINTAIN_FRAMERATE);
   EXPECT_THAT(source.sink_wants(), UnlimitedSinkWants());
   EXPECT_FALSE(stats_proxy_->GetStats().bw_limited_resolution);

   source.IncomingCapturedFrame(CreateFrame(1, 1280, 720));
   WaitForEncodedFrame(1);
   video_stream_encoder_->TriggerQualityLow();
   EXPECT_FALSE(stats_proxy_->GetStats().bw_limited_resolution);

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest,
        QualityScalingNotAllowedAndQPIsNotTrusted_BandwidthScalerDisable) {
   VideoEncoderConfig video_encoder_config = video_encoder_config_.Copy();

   // Disable scaling settings in encoder info.
   fake_encoder_.SetQualityScaling(false);
   // Set QP trusted in encoder info.
   fake_encoder_.SetIsQpTrusted(false);
   // Enable quality scaling in encoder config.
   video_encoder_config.is_quality_scaling_allowed = false;
   ConfigureEncoder(std::move(video_encoder_config));

   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);

   test::FrameForwarder source;
   video_stream_encoder_->SetSource(
       &source, webrtc::DegradationPreference::MAINTAIN_FRAMERATE);
   EXPECT_THAT(source.sink_wants(), UnlimitedSinkWants());
   EXPECT_FALSE(stats_proxy_->GetStats().bw_limited_resolution);

   source.IncomingCapturedFrame(CreateFrame(1, 1280, 720));
   WaitForEncodedFrame(1);
   video_stream_encoder_->TriggerQualityLow();
   EXPECT_FALSE(stats_proxy_->GetStats().bw_limited_resolution);

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest, EncoderProvideLimitsWhenQPIsNotTrusted) {
   // Set QP trusted in encoder info.
   fake_encoder_.SetIsQpTrusted(false);

   const int MinEncBitrateKbps = 30;
   const int MaxEncBitrateKbps = 100;
   const int MinStartBitrateKbp = 50;
   const VideoEncoder::ResolutionBitrateLimits encoder_bitrate_limits(
       /*frame_size_pixels=*/codec_width_ * codec_height_,
       /*min_start_bitrate_bps=*/MinStartBitrateKbp,
       /*min_bitrate_bps=*/MinEncBitrateKbps * 1000,
       /*max_bitrate_bps=*/MaxEncBitrateKbps * 1000);

   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);

   fake_encoder_.SetResolutionBitrateLimits({encoder_bitrate_limits});

   VideoEncoderConfig video_encoder_config;
   test::FillEncoderConfiguration(kVideoCodecH264, 1, &video_encoder_config);
   video_encoder_config.max_bitrate_bps = MaxEncBitrateKbps * 1000;
   video_encoder_config.simulcast_layers[0].min_bitrate_bps =
       MinEncBitrateKbps * 1000;
   video_stream_encoder_->ConfigureEncoder(video_encoder_config.Copy(),
                                           kMaxPayloadLength);

   video_source_.IncomingCapturedFrame(CreateFrame(1, nullptr));
   WaitForEncodedFrame(1);
   EXPECT_EQ(
       MaxEncBitrateKbps,
       static_cast<int>(bitrate_allocator_factory_.codec_config().maxBitrate));
   EXPECT_EQ(
       MinEncBitrateKbps,
       static_cast<int>(bitrate_allocator_factory_.codec_config().minBitrate));

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest, EncoderDoesnotProvideLimitsWhenQPIsNotTrusted) {
   // Set QP not trusted in encoder info.
   fake_encoder_.SetIsQpTrusted(false);

   absl::optional<VideoEncoder::ResolutionBitrateLimits> suitable_bitrate_limit =
       EncoderInfoSettings::
           GetSinglecastBitrateLimitForResolutionWhenQpIsUntrusted(
               codec_width_ * codec_height_,
               EncoderInfoSettings::
                   GetDefaultSinglecastBitrateLimitsWhenQpIsUntrusted());
   EXPECT_TRUE(suitable_bitrate_limit.has_value());

   const int max_encoder_bitrate = suitable_bitrate_limit->max_bitrate_bps;
   const int min_encoder_bitrate = suitable_bitrate_limit->min_bitrate_bps;
   const int target_encoder_bitrate = max_encoder_bitrate;
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       DataRate::BitsPerSec(target_encoder_bitrate),
       DataRate::BitsPerSec(target_encoder_bitrate),
       DataRate::BitsPerSec(target_encoder_bitrate), 0, 0, 0);

   VideoEncoderConfig video_encoder_config;
   test::FillEncoderConfiguration(kVideoCodecH264, 1, &video_encoder_config);
   video_encoder_config.max_bitrate_bps = max_encoder_bitrate;
   video_encoder_config.simulcast_layers[0].min_bitrate_bps =
       min_encoder_bitrate;
   video_stream_encoder_->ConfigureEncoder(video_encoder_config.Copy(),
                                           kMaxPayloadLength);

   video_source_.IncomingCapturedFrame(CreateFrame(1, nullptr));
   WaitForEncodedFrame(1);
   EXPECT_EQ(
       max_encoder_bitrate / 1000,
       static_cast<int>(bitrate_allocator_factory_.codec_config().maxBitrate));
   EXPECT_EQ(
       min_encoder_bitrate / 1000,
       static_cast<int>(bitrate_allocator_factory_.codec_config().minBitrate));

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest,
        RespectsLowerThanDefaultMinBitrateWhenQPIsNotTrusted) {
   // Set QP not trusted in encoder info.
   fake_encoder_.SetIsQpTrusted(false);

   absl::optional<VideoEncoder::ResolutionBitrateLimits> suitable_bitrate_limit =
       EncoderInfoSettings::
           GetSinglecastBitrateLimitForResolutionWhenQpIsUntrusted(
               codec_width_ * codec_height_,
               EncoderInfoSettings::
                   GetDefaultSinglecastBitrateLimitsWhenQpIsUntrusted());
   EXPECT_TRUE(suitable_bitrate_limit.has_value());

   const int max_encoder_bitrate = suitable_bitrate_limit->max_bitrate_bps;
   const int min_encoder_bitrate = suitable_bitrate_limit->min_bitrate_bps;
   const int target_encoder_bitrate = max_encoder_bitrate;
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       DataRate::BitsPerSec(target_encoder_bitrate),
       DataRate::BitsPerSec(target_encoder_bitrate),
       DataRate::BitsPerSec(target_encoder_bitrate), 0, 0, 0);

   VideoEncoderConfig video_encoder_config;
   test::FillEncoderConfiguration(kVideoCodecH264, 1, &video_encoder_config);
   // Set the max bitrate config to be lower than what the resolution bitrate
   // limits would suggest for the current resolution.
   video_encoder_config.max_bitrate_bps =
       (max_encoder_bitrate + min_encoder_bitrate) / 2;
   video_encoder_config.simulcast_layers[0].min_bitrate_bps =
       min_encoder_bitrate;
   video_stream_encoder_->ConfigureEncoder(video_encoder_config.Copy(),
                                           kMaxPayloadLength);

   video_source_.IncomingCapturedFrame(CreateFrame(1, nullptr));
   WaitForEncodedFrame(1);
   EXPECT_EQ(
       video_encoder_config.max_bitrate_bps / 1000,
       static_cast<int>(bitrate_allocator_factory_.codec_config().maxBitrate));
   EXPECT_EQ(
       min_encoder_bitrate / 1000,
       static_cast<int>(bitrate_allocator_factory_.codec_config().minBitrate));

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest, NormalComplexityWithMoreThanTwoCores) {
   ResetEncoder("VP9", /*num_stream=*/1, /*num_temporal_layers=*/1,
                /*num_spatial_layers=*/1,
                /*screenshare=*/false, /*allocation_callback_type=*/
                VideoStreamEncoder::BitrateAllocationCallbackType::
                    kVideoBitrateAllocationWhenScreenSharing,
                /*num_cores=*/3);

   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);
   video_source_.IncomingCapturedFrame(
       CreateFrame(1, /*width=*/320, /*height=*/180));
   WaitForEncodedFrame(1);
   EXPECT_EQ(fake_encoder_.LastEncoderComplexity(),
             VideoCodecComplexity::kComplexityNormal);
   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest,
        NormalComplexityWhenLowTierOptimizationsAreDisabled) {
   webrtc::test::ScopedKeyValueConfig field_trials(
       field_trials_, "WebRTC-VP9-LowTierOptimizations/Disabled/");

   ResetEncoder("VP9", /*num_stream=*/1, /*num_temporal_layers=*/1,
                /*num_spatial_layers=*/1,
                /*screenshare=*/false, /*allocation_callback_type=*/
                VideoStreamEncoder::BitrateAllocationCallbackType::
                    kVideoBitrateAllocationWhenScreenSharing,
                /*num_cores=*/2);

   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);
   video_source_.IncomingCapturedFrame(
       CreateFrame(1, /*width=*/320, /*height=*/180));
   WaitForEncodedFrame(1);
   EXPECT_EQ(fake_encoder_.LastEncoderComplexity(),
             VideoCodecComplexity::kComplexityNormal);
   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest, LowComplexityWithTwoCores) {
   ResetEncoder("VP9", /*num_stream=*/1, /*num_temporal_layers=*/1,
                /*num_spatial_layers=*/1,
                /*screenshare=*/false, /*allocation_callback_type=*/
                VideoStreamEncoder::BitrateAllocationCallbackType::
                    kVideoBitrateAllocationWhenScreenSharing,
                /*num_cores=*/2);

   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);
   video_source_.IncomingCapturedFrame(
       CreateFrame(1, /*width=*/320, /*height=*/180));
   WaitForEncodedFrame(1);
   EXPECT_EQ(fake_encoder_.LastEncoderComplexity(),
             VideoCodecComplexity::kComplexityLow);
   video_stream_encoder_->Stop();
 }

 #if !defined(WEBRTC_IOS)
 // TODO(bugs.webrtc.org/12401): Disabled because WebRTC-Video-QualityScaling is
 // disabled by default on iOS.
 TEST_F(VideoStreamEncoderTest, QualityScalingAllowed_QualityScalingEnabled) {
   VideoEncoderConfig video_encoder_config = video_encoder_config_.Copy();

   // Disable scaling settings in encoder info.
   fake_encoder_.SetQualityScaling(false);
   // Enable quality scaling in encoder config.
   video_encoder_config.is_quality_scaling_allowed = true;
   ConfigureEncoder(std::move(video_encoder_config));

   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);

   test::FrameForwarder source;
   video_stream_encoder_->SetSource(
       &source, webrtc::DegradationPreference::MAINTAIN_FRAMERATE);
   EXPECT_THAT(source.sink_wants(), UnlimitedSinkWants());
   EXPECT_FALSE(stats_proxy_->GetStats().bw_limited_resolution);

   source.IncomingCapturedFrame(CreateFrame(1, 1280, 720));
   WaitForEncodedFrame(1);
   video_stream_encoder_->TriggerQualityLow();
   EXPECT_TRUE(stats_proxy_->GetStats().bw_limited_resolution);

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest, QualityScalingAllowed_IsQpTrustedSetTrue) {
   VideoEncoderConfig video_encoder_config = video_encoder_config_.Copy();

   // Disable scaling settings in encoder info.
   fake_encoder_.SetQualityScaling(false);
   // Set QP trusted in encoder info.
   fake_encoder_.SetIsQpTrusted(true);
   // Enable quality scaling in encoder config.
   video_encoder_config.is_quality_scaling_allowed = true;
   ConfigureEncoder(std::move(video_encoder_config));

   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);

   test::FrameForwarder source;
   video_stream_encoder_->SetSource(
       &source, webrtc::DegradationPreference::MAINTAIN_FRAMERATE);
   EXPECT_THAT(source.sink_wants(), UnlimitedSinkWants());
   EXPECT_FALSE(stats_proxy_->GetStats().bw_limited_resolution);

   source.IncomingCapturedFrame(CreateFrame(1, 1280, 720));
   WaitForEncodedFrame(1);
   video_stream_encoder_->TriggerQualityLow();
   EXPECT_TRUE(stats_proxy_->GetStats().bw_limited_resolution);

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest, QualityScalingAllowed_IsQpTrustedSetFalse) {
   VideoEncoderConfig video_encoder_config = video_encoder_config_.Copy();

   // Disable scaling settings in encoder info.
   fake_encoder_.SetQualityScaling(false);
   // Set QP not trusted in encoder info.
   fake_encoder_.SetIsQpTrusted(false);
   // Enable quality scaling in encoder config.
   video_encoder_config.is_quality_scaling_allowed = true;
   ConfigureEncoder(std::move(video_encoder_config));

   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);

   test::FrameForwarder source;
   video_stream_encoder_->SetSource(
       &source, webrtc::DegradationPreference::MAINTAIN_FRAMERATE);
   EXPECT_THAT(source.sink_wants(), UnlimitedSinkWants());
   EXPECT_FALSE(stats_proxy_->GetStats().bw_limited_resolution);

   source.IncomingCapturedFrame(CreateFrame(1, 1280, 720));
   WaitForEncodedFrame(1);
   video_stream_encoder_->TriggerQualityLow();
   // When quality_scaler doesn't work and is_quality_scaling_allowed is
   // true,the bandwidth_quality_scaler_ works,so bw_limited_resolution is true.
   EXPECT_TRUE(stats_proxy_->GetStats().bw_limited_resolution);

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest,
        QualityScalingAllowedAndQPIsTrusted_BandwidthScalerDisable) {
   VideoEncoderConfig video_encoder_config = video_encoder_config_.Copy();

   // Disable scaling settings in encoder info.
   fake_encoder_.SetQualityScaling(false);
   // Set QP trusted in encoder info.
   fake_encoder_.SetIsQpTrusted(true);
   // Enable quality scaling in encoder config.
   video_encoder_config.is_quality_scaling_allowed = true;
   ConfigureEncoder(std::move(video_encoder_config));

   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);

   test::FrameForwarder source;
   video_stream_encoder_->SetSource(
       &source, webrtc::DegradationPreference::MAINTAIN_FRAMERATE);
   EXPECT_THAT(source.sink_wants(), UnlimitedSinkWants());
   EXPECT_FALSE(stats_proxy_->GetStats().bw_limited_resolution);

   source.IncomingCapturedFrame(CreateFrame(1, 1280, 720));
   WaitForEncodedFrame(1);
   video_stream_encoder_->TriggerQualityLow();
   // bandwidth_quality_scaler isn't working, but quality_scaler is working.
   EXPECT_TRUE(stats_proxy_->GetStats().bw_limited_resolution);

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest,
        QualityScalingAllowedAndQPIsNotTrusted_BandwidthScalerEnabled) {
   VideoEncoderConfig video_encoder_config = video_encoder_config_.Copy();

   // Disable scaling settings in encoder info.
   fake_encoder_.SetQualityScaling(false);
   // Set QP trusted in encoder info.
   fake_encoder_.SetIsQpTrusted(false);
   // Enable quality scaling in encoder config.
   video_encoder_config.is_quality_scaling_allowed = true;
   ConfigureEncoder(std::move(video_encoder_config));

   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);

   test::FrameForwarder source;
   video_stream_encoder_->SetSource(
       &source, webrtc::DegradationPreference::MAINTAIN_FRAMERATE);
   EXPECT_THAT(source.sink_wants(), UnlimitedSinkWants());
   EXPECT_FALSE(stats_proxy_->GetStats().bw_limited_resolution);

   source.IncomingCapturedFrame(CreateFrame(1, 1280, 720));
   WaitForEncodedFrame(1);
   video_stream_encoder_->TriggerQualityLow();
   EXPECT_TRUE(stats_proxy_->GetStats().bw_limited_resolution);

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest,
        RequestsRefreshFrameAfterEarlyDroppedNativeFrame) {
   // Send a native frame before encoder rates have been set. The encoder is
   // seen as paused at this time.
   rtc::Event frame_destroyed_event;
   video_source_.IncomingCapturedFrame(CreateFakeNativeFrame(
       /*ntp_time_ms=*/1, &frame_destroyed_event, codec_width_, codec_height_));

   // Frame should be dropped and destroyed.
   ExpectDroppedFrame();
   EXPECT_TRUE(frame_destroyed_event.Wait(kDefaultTimeout));
   EXPECT_EQ(video_source_.refresh_frames_requested_, 0);

   // Set bitrates, unpausing the encoder and triggering a request for a refresh
   // frame.
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);
   video_stream_encoder_->WaitUntilTaskQueueIsIdle();
   EXPECT_EQ(video_source_.refresh_frames_requested_, 1);

   video_stream_encoder_->Stop();
 }

 TEST_F(VideoStreamEncoderTest, RecreatesEncoderWhenEnableVp9SpatialLayer) {
   // Set up encoder to use VP9 SVC using two spatial layers.
   fake_encoder_.SetTemporalLayersSupported(/*spatial_idx=*/0, true);
   fake_encoder_.SetTemporalLayersSupported(/*spatial_idx*/ 1, true);
   VideoEncoderConfig video_encoder_config;
   test::FillEncoderConfiguration(VideoCodecType::kVideoCodecVP9,
                                  /* num_streams*/ 1, &video_encoder_config);
   video_encoder_config.max_bitrate_bps = 2 * kTargetBitrate.bps();
   video_encoder_config.content_type =
       VideoEncoderConfig::ContentType::kRealtimeVideo;
   VideoCodecVP9 vp9_settings = VideoEncoder::GetDefaultVp9Settings();
   vp9_settings.numberOfSpatialLayers = 2;
   vp9_settings.numberOfTemporalLayers = 2;
   vp9_settings.interLayerPred = InterLayerPredMode::kOn;
   vp9_settings.automaticResizeOn = false;
   video_encoder_config.encoder_specific_settings =
       rtc::make_ref_counted<VideoEncoderConfig::Vp9EncoderSpecificSettings>(
           vp9_settings);
   video_encoder_config.spatial_layers = GetSvcConfig(1280, 720,
                                                      /*fps=*/30.0,
                                                      /*first_active_layer=*/0,
                                                      /*num_spatial_layers=*/2,
                                                      /*num_temporal_layers=*/3,
                                                      /*is_screenshare=*/false);
   ConfigureEncoder(video_encoder_config.Copy(),
                    VideoStreamEncoder::BitrateAllocationCallbackType::
                        kVideoLayersAllocation);

   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);

   video_source_.IncomingCapturedFrame(CreateFrame(CurrentTimeMs(), 1280, 720));
   WaitForEncodedFrame(CurrentTimeMs());
   EXPECT_EQ(fake_encoder_.GetNumInitializations(), 1);

   // Turn off the top spatial layer. This does not require an encoder reset.
   video_encoder_config.spatial_layers[1].active = false;
   video_stream_encoder_->ConfigureEncoder(video_encoder_config.Copy(),
                                           kMaxPayloadLength, nullptr);

   time_controller_.AdvanceTime(TimeDelta::Millis(33));
   video_source_.IncomingCapturedFrame(CreateFrame(CurrentTimeMs(), 1280, 720));
   WaitForEncodedFrame(CurrentTimeMs());
   EXPECT_EQ(fake_encoder_.GetNumInitializations(), 1);

   // Turn on the top spatial layer again, this does require an encoder reset.
   video_encoder_config.spatial_layers[1].active = true;
   video_stream_encoder_->ConfigureEncoder(video_encoder_config.Copy(),
                                           kMaxPayloadLength, nullptr);

   time_controller_.AdvanceTime(TimeDelta::Millis(33));
   video_source_.IncomingCapturedFrame(CreateFrame(CurrentTimeMs(), 1280, 720));
   WaitForEncodedFrame(CurrentTimeMs());
   EXPECT_EQ(fake_encoder_.GetNumInitializations(), 2);

   video_stream_encoder_->Stop();
 }

 #endif  // !defined(WEBRTC_IOS)

 // Test parameters: (VideoCodecType codec, bool allow_i420_conversion)
 class VideoStreamEncoderWithRealEncoderTest
     : public VideoStreamEncoderTest,
       public ::testing::WithParamInterface<std::pair<VideoCodecType, bool>> {
  public:
   VideoStreamEncoderWithRealEncoderTest()
       : VideoStreamEncoderTest(),
         codec_type_(std::get<0>(GetParam())),
         allow_i420_conversion_(std::get<1>(GetParam())) {}

   void SetUp() override {
     VideoStreamEncoderTest::SetUp();
     std::unique_ptr<VideoEncoder> encoder;
     switch (codec_type_) {
       case kVideoCodecVP8:
         encoder = VP8Encoder::Create();
         break;
       case kVideoCodecVP9:
         encoder = VP9Encoder::Create();
         break;
       case kVideoCodecAV1:
         encoder = CreateLibaomAv1Encoder();
         break;
       case kVideoCodecH264:
         encoder = H264Encoder::Create();
         break;
       case kVideoCodecMultiplex:
         mock_encoder_factory_for_multiplex_ =
             std::make_unique<MockVideoEncoderFactory>();
         EXPECT_CALL(*mock_encoder_factory_for_multiplex_, Die);
         EXPECT_CALL(*mock_encoder_factory_for_multiplex_, CreateVideoEncoder)
             .WillRepeatedly([] { return VP8Encoder::Create(); });
         encoder = std::make_unique<MultiplexEncoderAdapter>(
             mock_encoder_factory_for_multiplex_.get(), SdpVideoFormat("VP8"),
             false);
         break;
       case kVideoCodecH265:
         // TODO(bugs.webrtc.org/13485): Use a fake encoder
         break;
       default:
         RTC_DCHECK_NOTREACHED();
     }
     ConfigureEncoderAndBitrate(codec_type_, std::move(encoder));
   }

   void TearDown() override {
     video_stream_encoder_->Stop();
     // Ensure `video_stream_encoder_` is destroyed before
     // `encoder_proxy_factory_`.
     video_stream_encoder_.reset();
     VideoStreamEncoderTest::TearDown();
   }

  protected:
   void ConfigureEncoderAndBitrate(VideoCodecType codec_type,
                                   std::unique_ptr<VideoEncoder> encoder) {
     // Configure VSE to use the encoder.
     encoder_ = std::move(encoder);
     encoder_proxy_factory_ = std::make_unique<test::VideoEncoderProxyFactory>(
         encoder_.get(), &encoder_selector_);
     video_send_config_.encoder_settings.encoder_factory =
         encoder_proxy_factory_.get();
     VideoEncoderConfig video_encoder_config;
     test::FillEncoderConfiguration(codec_type, 1, &video_encoder_config);
     video_encoder_config_ = video_encoder_config.Copy();
     ConfigureEncoder(video_encoder_config_.Copy());

     // Set bitrate to ensure frame is not dropped.
     video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
         kTargetBitrate, kTargetBitrate, kTargetBitrate, 0, 0, 0);
   }

   const VideoCodecType codec_type_;
   const bool allow_i420_conversion_;
   NiceMock<MockEncoderSelector> encoder_selector_;
   std::unique_ptr<test::VideoEncoderProxyFactory> encoder_proxy_factory_;
   std::unique_ptr<VideoEncoder> encoder_;
   std::unique_ptr<MockVideoEncoderFactory> mock_encoder_factory_for_multiplex_;
 };

 TEST_P(VideoStreamEncoderWithRealEncoderTest, EncoderMapsNativeI420) {
   auto native_i420_frame = test::CreateMappableNativeFrame(
       1, VideoFrameBuffer::Type::kI420, codec_width_, codec_height_);
   video_source_.IncomingCapturedFrame(native_i420_frame);
   WaitForEncodedFrame(codec_width_, codec_height_);

   auto mappable_native_buffer =
       test::GetMappableNativeBufferFromVideoFrame(native_i420_frame);
   std::vector<rtc::scoped_refptr<VideoFrameBuffer>> mapped_frame_buffers =
       mappable_native_buffer->GetMappedFramedBuffers();
   ASSERT_EQ(mapped_frame_buffers.size(), 1u);
   EXPECT_EQ(mapped_frame_buffers[0]->width(), codec_width_);
   EXPECT_EQ(mapped_frame_buffers[0]->height(), codec_height_);
   EXPECT_EQ(mapped_frame_buffers[0]->type(), VideoFrameBuffer::Type::kI420);
 }

 TEST_P(VideoStreamEncoderWithRealEncoderTest, EncoderMapsNativeNV12) {
   auto native_nv12_frame = test::CreateMappableNativeFrame(
       1, VideoFrameBuffer::Type::kNV12, codec_width_, codec_height_);
   video_source_.IncomingCapturedFrame(native_nv12_frame);
   WaitForEncodedFrame(codec_width_, codec_height_);

   auto mappable_native_buffer =
       test::GetMappableNativeBufferFromVideoFrame(native_nv12_frame);
   std::vector<rtc::scoped_refptr<VideoFrameBuffer>> mapped_frame_buffers =
       mappable_native_buffer->GetMappedFramedBuffers();
   ASSERT_EQ(mapped_frame_buffers.size(), 1u);
   EXPECT_EQ(mapped_frame_buffers[0]->width(), codec_width_);
   EXPECT_EQ(mapped_frame_buffers[0]->height(), codec_height_);
   EXPECT_EQ(mapped_frame_buffers[0]->type(), VideoFrameBuffer::Type::kNV12);

   if (!allow_i420_conversion_) {
     EXPECT_FALSE(mappable_native_buffer->DidConvertToI420());
   }
 }

 TEST_P(VideoStreamEncoderWithRealEncoderTest, HandlesLayerToggling) {
   if (codec_type_ == kVideoCodecMultiplex) {
     // Multiplex codec here uses wrapped mock codecs, ignore for this test.
     return;
   }

   const size_t kNumSpatialLayers = 3u;
   const float kDownscaleFactors[] = {4.0, 2.0, 1.0};
   const int kFrameWidth = 1280;
   const int kFrameHeight = 720;
   const rtc::VideoSinkWants::FrameSize kLayer0Size(
       kFrameWidth / kDownscaleFactors[0], kFrameHeight / kDownscaleFactors[0]);
   const rtc::VideoSinkWants::FrameSize kLayer1Size(
       kFrameWidth / kDownscaleFactors[1], kFrameHeight / kDownscaleFactors[1]);
   const rtc::VideoSinkWants::FrameSize kLayer2Size(
       kFrameWidth / kDownscaleFactors[2], kFrameHeight / kDownscaleFactors[2]);

   VideoEncoderConfig config;
   webrtc::VideoEncoder::EncoderInfo encoder_info;
   if (codec_type_ == VideoCodecType::kVideoCodecVP9) {
     test::FillEncoderConfiguration(codec_type_, 1, &config);
     config.max_bitrate_bps = kSimulcastTargetBitrate.bps();
     VideoCodecVP9 vp9_settings = VideoEncoder::GetDefaultVp9Settings();
     vp9_settings.numberOfSpatialLayers = kNumSpatialLayers;
     vp9_settings.numberOfTemporalLayers = 3;
     vp9_settings.automaticResizeOn = false;
     config.encoder_specific_settings =
         rtc::make_ref_counted<VideoEncoderConfig::Vp9EncoderSpecificSettings>(
             vp9_settings);
     config.spatial_layers = GetSvcConfig(kFrameWidth, kFrameHeight,
                                          /*fps=*/30.0,
                                          /*first_active_layer=*/0,
                                          /*num_spatial_layers=*/3,
                                          /*num_temporal_layers=*/3,
                                          /*is_screenshare=*/false);
   } else if (codec_type_ == VideoCodecType::kVideoCodecAV1) {
     test::FillEncoderConfiguration(codec_type_, 1, &config);
     config.max_bitrate_bps = kSimulcastTargetBitrate.bps();
     config.spatial_layers = GetSvcConfig(kFrameWidth, kFrameHeight,
                                          /*fps=*/30.0,
                                          /*first_active_layer=*/0,
                                          /*num_spatial_layers=*/3,
                                          /*num_temporal_layers=*/3,
                                          /*is_screenshare=*/false);
     config.simulcast_layers[0].scalability_mode = ScalabilityMode::kL3T3_KEY;
   } else {
     // Simulcast for VP8/H264.
     test::FillEncoderConfiguration(codec_type_, kNumSpatialLayers, &config);
     for (size_t i = 0; i < kNumSpatialLayers; ++i) {
       config.simulcast_layers[i].scale_resolution_down_by =
           kDownscaleFactors[i];
       config.simulcast_layers[i].active = true;
     }
     if (codec_type_ == VideoCodecType::kVideoCodecH264) {
       // Turn off frame dropping to prevent flakiness.
       config.frame_drop_enabled = false;
     }
   }

   auto set_layer_active = [&](int layer_idx, bool active) {
     if (codec_type_ == VideoCodecType::kVideoCodecVP9 ||
         codec_type_ == VideoCodecType::kVideoCodecAV1) {
       config.spatial_layers[layer_idx].active = active;
     } else {
       config.simulcast_layers[layer_idx].active = active;
     }
   };

   config.video_stream_factory =
       rtc::make_ref_counted<cricket::EncoderStreamFactory>(
           CodecTypeToPayloadString(codec_type_), /*max qp*/ 56,
           /*screencast*/ false,
           /*screenshare enabled*/ false, encoder_info);
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kSimulcastTargetBitrate, kSimulcastTargetBitrate, kSimulcastTargetBitrate,
       0, 0, 0);

   // Capture a frame with all layers active.
   sink_.SetNumExpectedLayers(kNumSpatialLayers);
   video_stream_encoder_->ConfigureEncoder(config.Copy(), kMaxPayloadLength);
   int64_t timestamp_ms = kFrameIntervalMs;
   video_source_.IncomingCapturedFrame(
       CreateFrame(timestamp_ms, kFrameWidth, kFrameHeight));

   WaitForEncodedFrame(kLayer2Size.width, kLayer2Size.height);
   video_stream_encoder_->WaitUntilTaskQueueIsIdle();

   // Capture a frame with one of the layers inactive.
   set_layer_active(2, false);
   sink_.SetNumExpectedLayers(kNumSpatialLayers - 1);
   video_stream_encoder_->ConfigureEncoder(config.Copy(), kMaxPayloadLength);
   timestamp_ms += kFrameIntervalMs;
   video_source_.IncomingCapturedFrame(
       CreateFrame(timestamp_ms, kFrameWidth, kFrameHeight));
   WaitForEncodedFrame(kLayer1Size.width, kLayer1Size.height);

   // New target bitrates signaled based on lower resolution.
   DataRate kTwoLayerBitrate = DataRate::KilobitsPerSec(833);
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       kTwoLayerBitrate, kTwoLayerBitrate, kTwoLayerBitrate, 0, 0, 0);
   video_stream_encoder_->WaitUntilTaskQueueIsIdle();

   // Re-enable the top layer.
   set_layer_active(2, true);
   sink_.SetNumExpectedLayers(kNumSpatialLayers);
   video_stream_encoder_->ConfigureEncoder(config.Copy(), kMaxPayloadLength);
   video_stream_encoder_->WaitUntilTaskQueueIsIdle();

   // Bitrate target adjusted back up to enable HD layer...
   video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
       DataRate::KilobitsPerSec(1800), DataRate::KilobitsPerSec(1800),
       DataRate::KilobitsPerSec(1800), 0, 0, 0);
   video_stream_encoder_->WaitUntilTaskQueueIsIdle();

   // ...then add a new frame.
   timestamp_ms += kFrameIntervalMs;
   video_source_.IncomingCapturedFrame(
       CreateFrame(timestamp_ms, kFrameWidth, kFrameHeight));
   WaitForEncodedFrame(kLayer2Size.width, kLayer2Size.height);
   video_stream_encoder_->WaitUntilTaskQueueIsIdle();

   video_stream_encoder_->Stop();
 }

 std::string TestParametersVideoCodecAndAllowI420ConversionToString(
     testing::TestParamInfo<std::pair<VideoCodecType, bool>> info) {
   VideoCodecType codec_type = std::get<0>(info.param);
   bool allow_i420_conversion = std::get<1>(info.param);
   return std::string(CodecTypeToPayloadString(codec_type)) +
          (allow_i420_conversion ? "_AllowToI420" : "_DisallowToI420");
 }

 constexpr std::pair<VideoCodecType, bool> kVP8DisallowConversion =
     std::make_pair(kVideoCodecVP8, /*allow_i420_conversion=*/false);
 constexpr std::pair<VideoCodecType, bool> kVP9DisallowConversion =
     std::make_pair(kVideoCodecVP9, /*allow_i420_conversion=*/false);
 constexpr std::pair<VideoCodecType, bool> kAV1AllowConversion =
     std::make_pair(kVideoCodecAV1, /*allow_i420_conversion=*/false);
 constexpr std::pair<VideoCodecType, bool> kMultiplexDisallowConversion =
     std::make_pair(kVideoCodecMultiplex, /*allow_i420_conversion=*/false);
 #if defined(WEBRTC_USE_H264)
 constexpr std::pair<VideoCodecType, bool> kH264AllowConversion =
     std::make_pair(kVideoCodecH264, /*allow_i420_conversion=*/true);

 // The windows compiler does not tolerate #if statements inside the
 // INSTANTIATE_TEST_SUITE_P() macro, so we have to have two definitions (with
 // and without H264).
 INSTANTIATE_TEST_SUITE_P(
     All,
     VideoStreamEncoderWithRealEncoderTest,
     ::testing::Values(kVP8DisallowConversion,
                       kVP9DisallowConversion,
                       kAV1AllowConversion,
                       kMultiplexDisallowConversion,
                       kH264AllowConversion),
     TestParametersVideoCodecAndAllowI420ConversionToString);
 #else
 INSTANTIATE_TEST_SUITE_P(
     All,
     VideoStreamEncoderWithRealEncoderTest,
     ::testing::Values(kVP8DisallowConversion,
                       kVP9DisallowConversion,
                       kAV1AllowConversion,
                       kMultiplexDisallowConversion),
     TestParametersVideoCodecAndAllowI420ConversionToString);
 #endif

 class ReconfigureEncoderTest : public VideoStreamEncoderTest {
  protected:
   void RunTest(const std::vector<VideoStream>& configs,
                const int expected_num_init_encode) {
     ConfigureEncoder(configs[0]);
     OnBitrateUpdated(kTargetBitrate);
     InsertFrameAndWaitForEncoded();
     EXPECT_EQ(1, sink_.number_of_reconfigurations());
     ExpectEqual(bitrate_allocator_factory_.codec_config(), configs[0]);
     EXPECT_EQ(1, fake_encoder_.GetNumInitializations());
     ExpectEqual(fake_encoder_.config(), configs[0]);

     // Reconfigure encoder, the encoder should only be reconfigured if needed.
     ConfigureEncoder(configs[1]);
     InsertFrameAndWaitForEncoded();
     EXPECT_EQ(2, sink_.number_of_reconfigurations());
     ExpectEqual(bitrate_allocator_factory_.codec_config(), configs[1]);
     EXPECT_EQ(expected_num_init_encode, fake_encoder_.GetNumInitializations());
     if (expected_num_init_encode > 1)
       ExpectEqual(fake_encoder_.config(), configs[1]);

     video_stream_encoder_->Stop();
   }

   void ConfigureEncoder(const VideoStream& stream) {
     VideoEncoderConfig config;
     webrtc::VideoEncoder::EncoderInfo encoder_info;

     test::FillEncoderConfiguration(kVideoCodecVP8, /*num_streams=*/1, &config);
     config.max_bitrate_bps = stream.max_bitrate_bps;
     config.simulcast_layers[0] = stream;
     config.video_stream_factory =
         rtc::make_ref_counted<cricket::EncoderStreamFactory>(
             /*codec_name=*/"VP8", /*max_qp=*/0, /*is_screenshare=*/false,
             /*conference_mode=*/false, encoder_info);
     video_stream_encoder_->ConfigureEncoder(std::move(config),
                                             kMaxPayloadLength);
   }

   void OnBitrateUpdated(DataRate bitrate) {
     video_stream_encoder_->OnBitrateUpdatedAndWaitForManagedResources(
         bitrate, bitrate, bitrate, 0, 0, 0);
   }

   void InsertFrameAndWaitForEncoded() {
     timestamp_ms_ += kFrameIntervalMs;
     video_source_.IncomingCapturedFrame(
         CreateFrame(timestamp_ms_, kWidth, kHeight));
     sink_.WaitForEncodedFrame(timestamp_ms_);
   }

   void ExpectEqual(const VideoCodec& actual,
                    const VideoStream& expected) const {
     EXPECT_EQ(actual.numberOfSimulcastStreams, 1);
     EXPECT_EQ(actual.simulcastStream[0].maxFramerate, expected.max_framerate);
     EXPECT_EQ(actual.simulcastStream[0].minBitrate * 1000,
               static_cast<unsigned int>(expected.min_bitrate_bps));
     EXPECT_EQ(actual.simulcastStream[0].maxBitrate * 1000,
               static_cast<unsigned int>(expected.max_bitrate_bps));
     EXPECT_EQ(actual.simulcastStream[0].width,
               kWidth / expected.scale_resolution_down_by);
     EXPECT_EQ(actual.simulcastStream[0].height,
               kHeight / expected.scale_resolution_down_by);
     EXPECT_EQ(actual.simulcastStream[0].numberOfTemporalLayers,
               expected.num_temporal_layers);
     EXPECT_EQ(actual.GetScalabilityMode(), expected.scalability_mode);
   }

   VideoStream DefaultConfig() const {
     VideoStream stream;
     stream.max_framerate = 25;
     stream.min_bitrate_bps = 35000;
     stream.max_bitrate_bps = 900000;
     stream.scale_resolution_down_by = 1.0;
     stream.num_temporal_layers = 1;
     stream.bitrate_priority = 1.0;
     stream.scalability_mode = absl::nullopt;
     return stream;
   }

   const int kWidth = 640;
   const int kHeight = 360;
   int64_t timestamp_ms_ = 0;
 };

 TEST_F(ReconfigureEncoderTest, NotReconfiguredIfMaxFramerateChanges) {
   VideoStream config1 = DefaultConfig();
   VideoStream config2 = config1;
   config2.max_framerate++;

   RunTest({config1, config2}, /*expected_num_init_encode=*/1);
 }

 TEST_F(ReconfigureEncoderTest, NotReconfiguredIfMinBitrateChanges) {
   VideoStream config1 = DefaultConfig();
   VideoStream config2 = config1;
   config2.min_bitrate_bps += 10000;

   RunTest({config1, config2}, /*expected_num_init_encode=*/1);
 }

 TEST_F(ReconfigureEncoderTest, NotReconfiguredIfMaxBitrateChanges) {
   VideoStream config1 = DefaultConfig();
   VideoStream config2 = config1;
   config2.max_bitrate_bps += 100000;

   RunTest({config1, config2}, /*expected_num_init_encode=*/1);
 }

 TEST_F(ReconfigureEncoderTest, NotReconfiguredIfBitratePriorityChanges) {
   VideoStream config1 = DefaultConfig();
   VideoStream config2 = config1;
   config2.bitrate_priority = config1.bitrate_priority.value() * 2.0;

   RunTest({config1, config2}, /*expected_num_init_encode=*/1);
 }

 TEST_F(ReconfigureEncoderTest, ReconfiguredIfResolutionChanges) {
   VideoStream config1 = DefaultConfig();
   VideoStream config2 = config1;
   config2.scale_resolution_down_by *= 2;

   RunTest({config1, config2}, /*expected_num_init_encode=*/2);
 }

 TEST_F(ReconfigureEncoderTest, ReconfiguredIfNumTemporalLayerChanges) {
   VideoStream config1 = DefaultConfig();
   VideoStream config2 = config1;
   config2.num_temporal_layers = config1.num_temporal_layers.value() + 1;

   RunTest({config1, config2}, /*expected_num_init_encode=*/2);
 }

 TEST_F(ReconfigureEncoderTest, ReconfiguredIfScalabilityModeChanges) {
   VideoStream config1 = DefaultConfig();
   VideoStream config2 = config1;
   config2.scalability_mode = ScalabilityMode::kL2T1;

   RunTest({config1, config2}, /*expected_num_init_encode=*/2);
 }

 TEST_F(ReconfigureEncoderTest,
        UpdatesNumTemporalLayersFromScalabilityModeChanges) {
   VideoStream config1 = DefaultConfig();
   VideoStream config2 = config1;
   config2.scalability_mode = ScalabilityMode::kL1T2;
   config2.num_temporal_layers = 2;

   RunTest({config1, config2}, /*expected_num_init_encode=*/2);
 }

 // Simple test that just creates and then immediately destroys an encoder.
 // The purpose of the test is to make sure that nothing bad happens if the
 // initialization step on the encoder queue, doesn't run.
 TEST(VideoStreamEncoderSimpleTest, CreateDestroy) {
   class SuperLazyTaskQueue : public webrtc::TaskQueueBase {
    public:
     SuperLazyTaskQueue() = default;
     ~SuperLazyTaskQueue() override = default;

    private:
     void Delete() override { delete this; }
     void PostTaskImpl(absl::AnyInvocable<void() &&> task,
                       const PostTaskTraits& traits,
                       const Location& location) override {
       // meh.
     }
     void PostDelayedTaskImpl(absl::AnyInvocable<void() &&> task,
                              TimeDelta delay,
                              const PostDelayedTaskTraits& traits,
                              const Location& location) override {
       ADD_FAILURE();
     }
   };

   // Lots of boiler plate.
   test::ScopedKeyValueConfig field_trials;
   GlobalSimulatedTimeController time_controller(Timestamp::Zero());
   auto stats_proxy = std::make_unique<MockableSendStatisticsProxy>(
       time_controller.GetClock(), VideoSendStream::Config(nullptr),
       webrtc::VideoEncoderConfig::ContentType::kRealtimeVideo, field_trials);
   SimpleVideoStreamEncoderFactory::MockFakeEncoder mock_fake_encoder(
       time_controller.GetClock());
   test::VideoEncoderProxyFactory encoder_factory(&mock_fake_encoder);
   std::unique_ptr<VideoBitrateAllocatorFactory> bitrate_allocator_factory =
       CreateBuiltinVideoBitrateAllocatorFactory();
   VideoStreamEncoderSettings encoder_settings{
       VideoEncoder::Capabilities(/*loss_notification=*/false)};
   encoder_settings.encoder_factory = &encoder_factory;
   encoder_settings.bitrate_allocator_factory = bitrate_allocator_factory.get();

   auto adapter = std::make_unique<MockFrameCadenceAdapter>();
   EXPECT_CALL((*adapter.get()), Initialize).WillOnce(Return());

   std::unique_ptr<webrtc::TaskQueueBase, webrtc::TaskQueueDeleter>
       encoder_queue(new SuperLazyTaskQueue());

   // Construct a VideoStreamEncoder instance and let it go out of scope without
   // doing anything else (including calling Stop()). This should be fine since
   // the posted init task will simply be deleted.
   auto encoder = std::make_unique<VideoStreamEncoder>(
       time_controller.GetClock(), 1, stats_proxy.get(), encoder_settings,
       std::make_unique<CpuOveruseDetectorProxy>(stats_proxy.get()),
       std::move(adapter), std::move(encoder_queue),
       VideoStreamEncoder::BitrateAllocationCallbackType::
           kVideoBitrateAllocation,
       field_trials);

   // Stop the encoder explicitly. This additional step tests if we could
   // hang when calling stop and the TQ has been stopped and/or isn't accepting
   // any more tasks.
   encoder->Stop();
 }

 TEST(VideoStreamEncoderFrameCadenceTest, ActivatesFrameCadenceOnContentType) {
   auto adapter = std::make_unique<MockFrameCadenceAdapter>();
   auto* adapter_ptr = adapter.get();
   SimpleVideoStreamEncoderFactory factory;
   FrameCadenceAdapterInterface::Callback* video_stream_encoder_callback =
       nullptr;
   EXPECT_CALL(*adapter_ptr, Initialize)
       .WillOnce(Invoke([&video_stream_encoder_callback](
                            FrameCadenceAdapterInterface::Callback* callback) {
         video_stream_encoder_callback = callback;
       }));
   TaskQueueBase* encoder_queue = nullptr;
   auto video_stream_encoder =
       factory.Create(std::move(adapter), &encoder_queue);

   // First a call before we know the frame size and hence cannot compute the
   // number of simulcast layers.
   EXPECT_CALL(*adapter_ptr, SetZeroHertzModeEnabled(Optional(Field(
                                 &FrameCadenceAdapterInterface::
                                     ZeroHertzModeParams::num_simulcast_layers,
                                 Eq(0u)))));
   VideoEncoderConfig config;
   test::FillEncoderConfiguration(kVideoCodecVP8, 1, &config);
   config.content_type = VideoEncoderConfig::ContentType::kScreen;
   video_stream_encoder->ConfigureEncoder(std::move(config), 0);
   factory.DepleteTaskQueues();

   // Then a call as we've computed the number of simulcast layers after a passed
   // frame.
   EXPECT_CALL(*adapter_ptr, SetZeroHertzModeEnabled(Optional(Field(
                                 &FrameCadenceAdapterInterface::
                                     ZeroHertzModeParams::num_simulcast_layers,
                                 Gt(0u)))));
   PassAFrame(encoder_queue, video_stream_encoder_callback, /*ntp_time_ms=*/1);
   factory.DepleteTaskQueues();
   Mock::VerifyAndClearExpectations(adapter_ptr);

   // Expect a disabled zero-hertz mode after passing realtime video.
   EXPECT_CALL(*adapter_ptr, SetZeroHertzModeEnabled(Eq(absl::nullopt)));
   VideoEncoderConfig config2;
   test::FillEncoderConfiguration(kVideoCodecVP8, 1, &config2);
   config2.content_type = VideoEncoderConfig::ContentType::kRealtimeVideo;
   video_stream_encoder->ConfigureEncoder(std::move(config2), 0);
   PassAFrame(encoder_queue, video_stream_encoder_callback, /*ntp_time_ms=*/2);
   factory.DepleteTaskQueues();
 }

 TEST(VideoStreamEncoderFrameCadenceTest,
      ForwardsFramesIntoFrameCadenceAdapter) {
   auto adapter = std::make_unique<MockFrameCadenceAdapter>();
   auto* adapter_ptr = adapter.get();
   test::FrameForwarder video_source;
   SimpleVideoStreamEncoderFactory factory;
   auto video_stream_encoder = factory.Create(std::move(adapter));
   video_stream_encoder->SetSource(
       &video_source, webrtc::DegradationPreference::MAINTAIN_FRAMERATE);

   EXPECT_CALL(*adapter_ptr, OnFrame);
   auto buffer = rtc::make_ref_counted<NV12Buffer>(/*width=*/16, /*height=*/16);
   video_source.IncomingCapturedFrame(
       VideoFrame::Builder().set_video_frame_buffer(std::move(buffer)).build());
 }

 TEST(VideoStreamEncoderFrameCadenceTest, UsesFrameCadenceAdapterForFrameRate) {
   auto adapter = std::make_unique<MockFrameCadenceAdapter>();
   auto* adapter_ptr = adapter.get();
   test::FrameForwarder video_source;
   SimpleVideoStreamEncoderFactory factory;
   FrameCadenceAdapterInterface::Callback* video_stream_encoder_callback =
       nullptr;
   EXPECT_CALL(*adapter_ptr, Initialize)
       .WillOnce(Invoke([&video_stream_encoder_callback](
                            FrameCadenceAdapterInterface::Callback* callback) {
         video_stream_encoder_callback = callback;
       }));
   TaskQueueBase* encoder_queue = nullptr;
   auto video_stream_encoder =
       factory.Create(std::move(adapter), &encoder_queue);

   // This is just to make the VSE operational. We'll feed a frame directly by
   // the callback interface.
   video_stream_encoder->SetSource(
       &video_source, webrtc::DegradationPreference::MAINTAIN_FRAMERATE);

   VideoEncoderConfig video_encoder_config;
   test::FillEncoderConfiguration(kVideoCodecGeneric, 1, &video_encoder_config);
   video_stream_encoder->ConfigureEncoder(std::move(video_encoder_config),
                                          /*max_data_payload_length=*/1000);

   EXPECT_CALL(*adapter_ptr, GetInputFrameRateFps);
   EXPECT_CALL(*adapter_ptr, UpdateFrameRate);
   PassAFrame(encoder_queue, video_stream_encoder_callback, /*ntp_time_ms=*/1);
   factory.DepleteTaskQueues();
 }

 TEST(VideoStreamEncoderFrameCadenceTest,
      DeactivatesActivatesLayersOnBitrateChanges) {
   auto adapter = std::make_unique<MockFrameCadenceAdapter>();
   auto* adapter_ptr = adapter.get();
   SimpleVideoStreamEncoderFactory factory;
   FrameCadenceAdapterInterface::Callback* video_stream_encoder_callback =
       nullptr;
   EXPECT_CALL(*adapter_ptr, Initialize)
       .WillOnce(Invoke([&video_stream_encoder_callback](
                            FrameCadenceAdapterInterface::Callback* callback) {
         video_stream_encoder_callback = callback;
       }));
   TaskQueueBase* encoder_queue = nullptr;
   auto video_stream_encoder =
       factory.Create(std::move(adapter), &encoder_queue);

   // Configure 2 simulcast layers. FillEncoderConfiguration sets min bitrates to
   //  {150000, 450000}.
   VideoEncoderConfig video_encoder_config;
   test::FillEncoderConfiguration(kVideoCodecVP8, 2, &video_encoder_config);
   video_stream_encoder->ConfigureEncoder(video_encoder_config.Copy(),
                                          kMaxPayloadLength);
   // Ensure an encoder is created.
   PassAFrame(encoder_queue, video_stream_encoder_callback, /*ntp_time_ms=*/1);

   // Both layers enabled at 1 MBit/s.
   video_stream_encoder->OnBitrateUpdated(
       DataRate::KilobitsPerSec(1000), DataRate::KilobitsPerSec(1000),
       DataRate::KilobitsPerSec(1000), 0, 0, 0);
   EXPECT_CALL(*adapter_ptr, UpdateLayerStatus(0, /*enabled=*/true));
   EXPECT_CALL(*adapter_ptr, UpdateLayerStatus(1, /*enabled=*/true));
   factory.DepleteTaskQueues();
   Mock::VerifyAndClearExpectations(adapter_ptr);

   // Layer 1 disabled at 200 KBit/s.
   video_stream_encoder->OnBitrateUpdated(
       DataRate::KilobitsPerSec(200), DataRate::KilobitsPerSec(200),
       DataRate::KilobitsPerSec(200), 0, 0, 0);
   EXPECT_CALL(*adapter_ptr, UpdateLayerStatus(0, /*enabled=*/true));
   EXPECT_CALL(*adapter_ptr, UpdateLayerStatus(1, /*enabled=*/false));
   factory.DepleteTaskQueues();
   Mock::VerifyAndClearExpectations(adapter_ptr);

   // All layers off at suspended video.
   video_stream_encoder->OnBitrateUpdated(DataRate::Zero(), DataRate::Zero(),
                                          DataRate::Zero(), 0, 0, 0);
   EXPECT_CALL(*adapter_ptr, UpdateLayerStatus(0, /*enabled=*/false));
   EXPECT_CALL(*adapter_ptr, UpdateLayerStatus(1, /*enabled=*/false));
   factory.DepleteTaskQueues();
   Mock::VerifyAndClearExpectations(adapter_ptr);

   // Both layers enabled again back at 1 MBit/s.
   video_stream_encoder->OnBitrateUpdated(
       DataRate::KilobitsPerSec(1000), DataRate::KilobitsPerSec(1000),
       DataRate::KilobitsPerSec(1000), 0, 0, 0);
   EXPECT_CALL(*adapter_ptr, UpdateLayerStatus(0, /*enabled=*/true));
   EXPECT_CALL(*adapter_ptr, UpdateLayerStatus(1, /*enabled=*/true));
   factory.DepleteTaskQueues();
 }

 TEST(VideoStreamEncoderFrameCadenceTest, UpdatesQualityConvergence) {
   auto adapter = std::make_unique<MockFrameCadenceAdapter>();
   auto* adapter_ptr = adapter.get();
   SimpleVideoStreamEncoderFactory factory;
   FrameCadenceAdapterInterface::Callback* video_stream_encoder_callback =
       nullptr;
   EXPECT_CALL(*adapter_ptr, Initialize)
       .WillOnce(Invoke([&video_stream_encoder_callback](
                            FrameCadenceAdapterInterface::Callback* callback) {
         video_stream_encoder_callback = callback;
       }));
   TaskQueueBase* encoder_queue = nullptr;
   auto video_stream_encoder =
       factory.Create(std::move(adapter), &encoder_queue);

   // Configure 2 simulcast layers and setup 1 MBit/s to unpause the encoder.
   VideoEncoderConfig video_encoder_config;
   test::FillEncoderConfiguration(kVideoCodecVP8, 2, &video_encoder_config);
   video_stream_encoder->ConfigureEncoder(video_encoder_config.Copy(),
                                          kMaxPayloadLength);
   video_stream_encoder->OnBitrateUpdated(
       DataRate::KilobitsPerSec(1000), DataRate::KilobitsPerSec(1000),
       DataRate::KilobitsPerSec(1000), 0, 0, 0);

   // Pass a frame which has unconverged results.
   PassAFrame(encoder_queue, video_stream_encoder_callback, /*ntp_time_ms=*/1);
   EXPECT_CALL(factory.GetMockFakeEncoder(), EncodeHook)
       .WillRepeatedly(Invoke([](EncodedImage& encoded_image,
                                 rtc::scoped_refptr<EncodedImageBuffer> buffer) {
         encoded_image.qp_ = kVp8SteadyStateQpThreshold + 1;
         CodecSpecificInfo codec_specific;
         codec_specific.codecType = kVideoCodecVP8;
         return codec_specific;
       }));
   EXPECT_CALL(*adapter_ptr, UpdateLayerQualityConvergence(0, false));
   EXPECT_CALL(*adapter_ptr, UpdateLayerQualityConvergence(1, false));
   factory.DepleteTaskQueues();
   Mock::VerifyAndClearExpectations(adapter_ptr);
   Mock::VerifyAndClearExpectations(&factory.GetMockFakeEncoder());

   // Pass a frame which converges in layer 0 and not in layer 1.
   PassAFrame(encoder_queue, video_stream_encoder_callback, /*ntp_time_ms=*/2);
   EXPECT_CALL(factory.GetMockFakeEncoder(), EncodeHook)
       .WillRepeatedly(Invoke([](EncodedImage& encoded_image,
                                 rtc::scoped_refptr<EncodedImageBuffer> buffer) {
         // This sets simulcast index 0 content to be at target quality, while
         // index 1 content is not.
         encoded_image.qp_ = kVp8SteadyStateQpThreshold +
                             (encoded_image.SimulcastIndex() == 0 ? 0 : 1);
         CodecSpecificInfo codec_specific;
         codec_specific.codecType = kVideoCodecVP8;
         return codec_specific;
       }));
   EXPECT_CALL(*adapter_ptr, UpdateLayerQualityConvergence(0, true));
   EXPECT_CALL(*adapter_ptr, UpdateLayerQualityConvergence(1, false));
   factory.DepleteTaskQueues();
   Mock::VerifyAndClearExpectations(adapter_ptr);
   Mock::VerifyAndClearExpectations(&factory.GetMockFakeEncoder());
 }

 TEST(VideoStreamEncoderFrameCadenceTest,
      RequestsRefreshFramesWhenCadenceAdapterInstructs) {
   auto adapter = std::make_unique<MockFrameCadenceAdapter>();
   auto* adapter_ptr = adapter.get();
   MockVideoSourceInterface mock_source;
   SimpleVideoStreamEncoderFactory factory;
   FrameCadenceAdapterInterface::Callback* video_stream_encoder_callback =
       nullptr;
   EXPECT_CALL(*adapter_ptr, Initialize)
       .WillOnce(Invoke([&video_stream_encoder_callback](
                            FrameCadenceAdapterInterface::Callback* callback) {
         video_stream_encoder_callback = callback;
       }));
   TaskQueueBase* encoder_queue = nullptr;
   auto video_stream_encoder =
       factory.Create(std::move(adapter), &encoder_queue);
   video_stream_encoder->SetSource(
       &mock_source, webrtc::DegradationPreference::MAINTAIN_FRAMERATE);
   VideoEncoderConfig config;
   config.content_type = VideoEncoderConfig::ContentType::kScreen;
   test::FillEncoderConfiguration(kVideoCodecVP8, 1, &config);
   video_stream_encoder->ConfigureEncoder(std::move(config), 0);
   PassAFrame(encoder_queue, video_stream_encoder_callback, /*ntp_time_ms=*/2);
   // Ensure the encoder is set up.
   factory.DepleteTaskQueues();

   EXPECT_CALL(*adapter_ptr, ProcessKeyFrameRequest)
       .WillOnce(Invoke([video_stream_encoder_callback] {
         video_stream_encoder_callback->RequestRefreshFrame();
       }));
   EXPECT_CALL(mock_source, RequestRefreshFrame);
   video_stream_encoder->SendKeyFrame();
   factory.DepleteTaskQueues();
   Mock::VerifyAndClearExpectations(adapter_ptr);
   Mock::VerifyAndClearExpectations(&mock_source);

   EXPECT_CALL(*adapter_ptr, ProcessKeyFrameRequest);
   EXPECT_CALL(mock_source, RequestRefreshFrame).Times(0);
   video_stream_encoder->SendKeyFrame();
   factory.DepleteTaskQueues();
 }

 TEST(VideoStreamEncoderFrameCadenceTest,
      RequestsRefreshFrameForEarlyZeroHertzKeyFrameRequest) {
   SimpleVideoStreamEncoderFactory factory;
   auto encoder_queue =
       factory.GetTimeController()->GetTaskQueueFactory()->CreateTaskQueue(
           "EncoderQueue", TaskQueueFactory::Priority::NORMAL);

   // Enables zero-hertz mode.
   test::ScopedKeyValueConfig field_trials(
       "WebRTC-ZeroHertzScreenshare/Enabled/");
   auto adapter = FrameCadenceAdapterInterface::Create(
       factory.GetTimeController()->GetClock(), encoder_queue.get(),
       field_trials);
   FrameCadenceAdapterInterface* adapter_ptr = adapter.get();

   MockVideoSourceInterface mock_source;
   auto video_stream_encoder = factory.CreateWithEncoderQueue(
       std::move(adapter), std::move(encoder_queue), &field_trials);

   video_stream_encoder->SetSource(
       &mock_source, webrtc::DegradationPreference::MAINTAIN_FRAMERATE);
   VideoEncoderConfig config;
   config.content_type = VideoEncoderConfig::ContentType::kScreen;
   test::FillEncoderConfiguration(kVideoCodecVP8, 1, &config);
   video_stream_encoder->ConfigureEncoder(std::move(config), 0);

   // Eventually expect a refresh frame request when requesting a key frame
   // before initializing zero-hertz mode. This can happen in reality because the
   // threads invoking key frame requests and constraints setup aren't
   // synchronized.
   EXPECT_CALL(mock_source, RequestRefreshFrame);
   video_stream_encoder->SendKeyFrame();
   constexpr int kMaxFps = 30;
   adapter_ptr->OnConstraintsChanged(VideoTrackSourceConstraints{0, kMaxFps});
   factory.GetTimeController()->AdvanceTime(
       TimeDelta::Seconds(1) *
       FrameCadenceAdapterInterface::kOnDiscardedFrameRefreshFramePeriod /
       kMaxFps);
 }

 class VideoStreamEncoderFrameCadenceRestrictionTest : public ::testing::Test {
  public:
   VideoStreamEncoderFrameCadenceRestrictionTest()
       : adapter_ptr_(adapter_.get()),
         fake_resource_(FakeResource::Create("FakeResource")),
         video_stream_encoder_(
             factory_.Create(std::move(adapter_), &encoder_queue_)) {}

   ~VideoStreamEncoderFrameCadenceRestrictionTest() {
     factory_.DepleteTaskQueues();
   }

   void UpdateVideoSourceRestrictions(VideoSourceRestrictions restrictions) {
     encoder_queue_->PostTask([this, restrictions] {
       RTC_DCHECK_RUN_ON(encoder_queue_);
       video_stream_encoder_->OnVideoSourceRestrictionsUpdated(
           restrictions, VideoAdaptationCounters(), fake_resource_,
           VideoSourceRestrictions());
     });
   }

  protected:
   SimpleVideoStreamEncoderFactory factory_;
   std::unique_ptr<NiceMock<MockFrameCadenceAdapter>> adapter_{
       std::make_unique<NiceMock<MockFrameCadenceAdapter>>()};
   NiceMock<MockFrameCadenceAdapter>* adapter_ptr_;
   TaskQueueBase* encoder_queue_{nullptr};
   rtc::scoped_refptr<FakeResource> fake_resource_;
   VideoSourceRestrictions restrictions_;
   std::unique_ptr<SimpleVideoStreamEncoderFactory::AdaptedVideoStreamEncoder>
       video_stream_encoder_;
 };

 TEST_F(VideoStreamEncoderFrameCadenceRestrictionTest,
        UpdatesVideoSourceRestrictionsUnRestricted) {
   EXPECT_CALL(*adapter_ptr_, UpdateVideoSourceRestrictions(Eq(absl::nullopt)));
   UpdateVideoSourceRestrictions(VideoSourceRestrictions());
 }

 TEST_F(VideoStreamEncoderFrameCadenceRestrictionTest,
        UpdatesVideoSourceRestrictionsWithMaxFrameRateRestriction) {
   restrictions_.set_max_frame_rate(20);
   EXPECT_CALL(*adapter_ptr_, UpdateVideoSourceRestrictions(Optional(20)));
   UpdateVideoSourceRestrictions(restrictions_);
 }

 TEST_F(VideoStreamEncoderFrameCadenceRestrictionTest,
        UpdatesVideoSourceRestrictionsWithoutMaxFrameRateRestriction) {
   // Restrictions in resolution count as restriction updated, even though the
   // FPS is unlimited.
   restrictions_.set_max_pixels_per_frame(99);
   restrictions_.set_target_pixels_per_frame(101);
   EXPECT_CALL(*adapter_ptr_, UpdateVideoSourceRestrictions(Eq(absl::nullopt)));
   UpdateVideoSourceRestrictions(restrictions_);
 }

 }  // namespace webrtc