video/quality_scaling_tests.cc - src.git - Git at Google

 /*
  *  Copyright (c) 2018 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 <string>

 #include "api/test/video/function_video_encoder_factory.h"
 #include "media/engine/internal_encoder_factory.h"
 #include "modules/video_coding/codecs/h264/include/h264.h"
 #include "modules/video_coding/codecs/vp8/include/vp8.h"
 #include "modules/video_coding/codecs/vp9/include/vp9.h"
 #include "rtc_base/experiments/encoder_info_settings.h"
 #include "test/call_test.h"
 #include "test/field_trial.h"
 #include "test/frame_generator_capturer.h"

 namespace webrtc {
 namespace {
 constexpr int kInitialWidth = 1280;
 constexpr int kInitialHeight = 720;
 constexpr int kLowStartBps = 100000;
 constexpr int kHighStartBps = 1000000;
 constexpr int kDefaultVgaMinStartBps = 500000;  // From video_stream_encoder.cc
 constexpr int kTimeoutMs = 10000;  // Some tests are expected to time out.

 void SetEncoderSpecific(VideoEncoderConfig* encoder_config,
                         VideoCodecType type,
                         bool automatic_resize,
                         size_t num_spatial_layers) {
   if (type == kVideoCodecVP8) {
     VideoCodecVP8 vp8 = VideoEncoder::GetDefaultVp8Settings();
     vp8.automaticResizeOn = automatic_resize;
     encoder_config->encoder_specific_settings =
         rtc::make_ref_counted<VideoEncoderConfig::Vp8EncoderSpecificSettings>(
             vp8);
   } else if (type == kVideoCodecVP9) {
     VideoCodecVP9 vp9 = VideoEncoder::GetDefaultVp9Settings();
     vp9.automaticResizeOn = automatic_resize;
     vp9.numberOfSpatialLayers = num_spatial_layers;
     encoder_config->encoder_specific_settings =
         rtc::make_ref_counted<VideoEncoderConfig::Vp9EncoderSpecificSettings>(
             vp9);
   }
 }
 }  // namespace

 class QualityScalingTest : public test::CallTest {
  protected:
   const std::string kPrefix = "WebRTC-Video-QualityScaling/Enabled-";
   const std::string kEnd = ",0,0,0.9995,0.9999,1/";
   const absl::optional<VideoEncoder::ResolutionBitrateLimits>
       kSinglecastLimits720pVp8 =
           EncoderInfoSettings::GetDefaultSinglecastBitrateLimitsForResolution(
               kVideoCodecVP8,
               1280 * 720);
   const absl::optional<VideoEncoder::ResolutionBitrateLimits>
       kSinglecastLimits360pVp9 =
           EncoderInfoSettings::GetDefaultSinglecastBitrateLimitsForResolution(
               kVideoCodecVP9,
               640 * 360);
   const absl::optional<VideoEncoder::ResolutionBitrateLimits>
       kSinglecastLimits720pVp9 =
           EncoderInfoSettings::GetDefaultSinglecastBitrateLimitsForResolution(
               kVideoCodecVP9,
               1280 * 720);
 };

 class ScalingObserver : public test::SendTest {
  protected:
   struct TestParams {
     bool active;
     absl::optional<ScalabilityMode> scalability_mode;
   };
   ScalingObserver(const std::string& payload_name,
                   const std::vector<TestParams>& test_params,
                   int start_bps,
                   bool automatic_resize,
                   bool expect_scaling)
       : SendTest(expect_scaling ? kTimeoutMs * 4 : kTimeoutMs),
         encoder_factory_(
             [](const SdpVideoFormat& format) -> std::unique_ptr<VideoEncoder> {
               if (format.name == "VP8")
                 return VP8Encoder::Create();
               if (format.name == "VP9")
                 return VP9Encoder::Create();
               if (format.name == "H264")
                 return H264Encoder::Create(cricket::VideoCodec("H264"));
               RTC_DCHECK_NOTREACHED() << format.name;
               return nullptr;
             }),
         payload_name_(payload_name),
         test_params_(test_params),
         start_bps_(start_bps),
         automatic_resize_(automatic_resize),
         expect_scaling_(expect_scaling) {}

   DegradationPreference degradation_preference_ =
       DegradationPreference::MAINTAIN_FRAMERATE;

  private:
   void ModifySenderBitrateConfig(BitrateConstraints* bitrate_config) override {
     bitrate_config->start_bitrate_bps = start_bps_;
   }

   void ModifyVideoDegradationPreference(
       DegradationPreference* degradation_preference) override {
     *degradation_preference = degradation_preference_;
   }

   size_t GetNumVideoStreams() const override {
     return (payload_name_ == "VP9") ? 1 : test_params_.size();
   }

   void ModifyVideoConfigs(
       VideoSendStream::Config* send_config,
       std::vector<VideoReceiveStreamInterface::Config>* receive_configs,
       VideoEncoderConfig* encoder_config) override {
     send_config->encoder_settings.encoder_factory = &encoder_factory_;
     send_config->rtp.payload_name = payload_name_;
     send_config->rtp.payload_type = test::CallTest::kVideoSendPayloadType;
     encoder_config->video_format.name = payload_name_;
     const VideoCodecType codec_type = PayloadStringToCodecType(payload_name_);
     encoder_config->codec_type = codec_type;
     encoder_config->max_bitrate_bps =
         std::max(start_bps_, encoder_config->max_bitrate_bps);
     if (payload_name_ == "VP9") {
       // Simulcast layers indicates which spatial layers are active.
       encoder_config->simulcast_layers.resize(test_params_.size());
       encoder_config->simulcast_layers[0].max_bitrate_bps =
           encoder_config->max_bitrate_bps;
     }
     double scale_factor = 1.0;
     for (int i = test_params_.size() - 1; i >= 0; --i) {
       VideoStream& stream = encoder_config->simulcast_layers[i];
       stream.active = test_params_[i].active;
       stream.scalability_mode = test_params_[i].scalability_mode;
       stream.scale_resolution_down_by = scale_factor;
       scale_factor *= (payload_name_ == "VP9") ? 1.0 : 2.0;
     }
     encoder_config->frame_drop_enabled = true;
     SetEncoderSpecific(encoder_config, codec_type, automatic_resize_,
                        test_params_.size());
   }

   void PerformTest() override { EXPECT_EQ(expect_scaling_, Wait()); }

   test::FunctionVideoEncoderFactory encoder_factory_;
   const std::string payload_name_;
   const std::vector<TestParams> test_params_;
   const int start_bps_;
   const bool automatic_resize_;
   const bool expect_scaling_;
 };

 class DownscalingObserver
     : public ScalingObserver,
       public test::FrameGeneratorCapturer::SinkWantsObserver {
  public:
   DownscalingObserver(const std::string& payload_name,
                       const std::vector<TestParams>& test_params,
                       int start_bps,
                       bool automatic_resize,
                       bool expect_downscale)
       : ScalingObserver(payload_name,
                         test_params,
                         start_bps,
                         automatic_resize,
                         expect_downscale) {}

  private:
   void OnFrameGeneratorCapturerCreated(
       test::FrameGeneratorCapturer* frame_generator_capturer) override {
     frame_generator_capturer->SetSinkWantsObserver(this);
     frame_generator_capturer->ChangeResolution(kInitialWidth, kInitialHeight);
   }

   void OnSinkWantsChanged(rtc::VideoSinkInterface<VideoFrame>* sink,
                           const rtc::VideoSinkWants& wants) override {
     if (wants.max_pixel_count < kInitialWidth * kInitialHeight)
       observation_complete_.Set();
   }
 };

 class UpscalingObserver
     : public ScalingObserver,
       public test::FrameGeneratorCapturer::SinkWantsObserver {
  public:
   UpscalingObserver(const std::string& payload_name,
                     const std::vector<TestParams>& test_params,
                     int start_bps,
                     bool automatic_resize,
                     bool expect_upscale)
       : ScalingObserver(payload_name,
                         test_params,
                         start_bps,
                         automatic_resize,
                         expect_upscale) {}

   void SetDegradationPreference(DegradationPreference preference) {
     degradation_preference_ = preference;
   }

  private:
   void OnFrameGeneratorCapturerCreated(
       test::FrameGeneratorCapturer* frame_generator_capturer) override {
     frame_generator_capturer->SetSinkWantsObserver(this);
     frame_generator_capturer->ChangeResolution(kInitialWidth, kInitialHeight);
   }

   void OnSinkWantsChanged(rtc::VideoSinkInterface<VideoFrame>* sink,
                           const rtc::VideoSinkWants& wants) override {
     if (wants.max_pixel_count > last_wants_.max_pixel_count) {
       if (wants.max_pixel_count == std::numeric_limits<int>::max())
         observation_complete_.Set();
     }
     last_wants_ = wants;
   }

   rtc::VideoSinkWants last_wants_;
 };

 TEST_F(QualityScalingTest, AdaptsDownForHighQp_Vp8) {
   // qp_low:1, qp_high:1 -> kHighQp
   test::ScopedKeyValueConfig field_trials(field_trials_,
                                           kPrefix + "1,1,0,0,0,0" + kEnd);

   DownscalingObserver test("VP8", {{.active = true}}, kHighStartBps,
                            /*automatic_resize=*/true,
                            /*expect_downscale=*/true);
   RunBaseTest(&test);
 }

 TEST_F(QualityScalingTest, NoAdaptDownForHighQpIfScalingOff_Vp8) {
   // qp_low:1, qp_high:1 -> kHighQp
   test::ScopedKeyValueConfig field_trials(field_trials_,
                                           kPrefix + "1,1,0,0,0,0" + kEnd);

   DownscalingObserver test("VP8", {{.active = true}}, kHighStartBps,
                            /*automatic_resize=*/false,
                            /*expect_downscale=*/false);
   RunBaseTest(&test);
 }

 TEST_F(QualityScalingTest, NoAdaptDownForNormalQp_Vp8) {
   // qp_low:1, qp_high:127 -> kNormalQp
   test::ScopedKeyValueConfig field_trials(field_trials_,
                                           kPrefix + "1,127,0,0,0,0" + kEnd);

   DownscalingObserver test("VP8", {{.active = true}}, kHighStartBps,
                            /*automatic_resize=*/true,
                            /*expect_downscale=*/false);
   RunBaseTest(&test);
 }

 TEST_F(QualityScalingTest, AdaptsDownForLowStartBitrate_Vp8) {
   // qp_low:1, qp_high:127 -> kNormalQp
   test::ScopedKeyValueConfig field_trials(field_trials_,
                                           kPrefix + "1,127,0,0,0,0" + kEnd);

   DownscalingObserver test("VP8", {{.active = true}}, kLowStartBps,
                            /*automatic_resize=*/true,
                            /*expect_downscale=*/true);
   RunBaseTest(&test);
 }

 TEST_F(QualityScalingTest, AdaptsDownForLowStartBitrateAndThenUp) {
   // qp_low:127, qp_high:127 -> kLowQp
   test::ScopedKeyValueConfig field_trials(
       field_trials_,
       kPrefix + "127,127,0,0,0,0" + kEnd +
           "WebRTC-Video-BalancedDegradationSettings/"
           "pixels:230400|921600,fps:20|30,kbps:300|500/");  // should not affect

   UpscalingObserver test("VP8", {{.active = true}}, kDefaultVgaMinStartBps - 1,
                          /*automatic_resize=*/true, /*expect_upscale=*/true);
   RunBaseTest(&test);
 }

 TEST_F(QualityScalingTest, AdaptsDownAndThenUpWithBalanced) {
   // qp_low:127, qp_high:127 -> kLowQp
   test::ScopedKeyValueConfig field_trials(
       field_trials_, kPrefix + "127,127,0,0,0,0" + kEnd +
                          "WebRTC-Video-BalancedDegradationSettings/"
                          "pixels:230400|921600,fps:20|30,kbps:300|499/");

   UpscalingObserver test("VP8", {{.active = true}}, kDefaultVgaMinStartBps - 1,
                          /*automatic_resize=*/true, /*expect_upscale=*/true);
   test.SetDegradationPreference(DegradationPreference::BALANCED);
   RunBaseTest(&test);
 }

 TEST_F(QualityScalingTest, AdaptsDownButNotUpWithBalancedIfBitrateNotEnough) {
   // qp_low:127, qp_high:127 -> kLowQp
   test::ScopedKeyValueConfig field_trials(
       field_trials_, kPrefix + "127,127,0,0,0,0" + kEnd +
                          "WebRTC-Video-BalancedDegradationSettings/"
                          "pixels:230400|921600,fps:20|30,kbps:300|500/");

   UpscalingObserver test("VP8", {{.active = true}}, kDefaultVgaMinStartBps - 1,
                          /*automatic_resize=*/true, /*expect_upscale=*/false);
   test.SetDegradationPreference(DegradationPreference::BALANCED);
   RunBaseTest(&test);
 }

 TEST_F(QualityScalingTest, NoAdaptDownForLowStartBitrate_Simulcast) {
   // qp_low:1, qp_high:127 -> kNormalQp
   test::ScopedKeyValueConfig field_trials(field_trials_,
                                           kPrefix + "1,127,0,0,0,0" + kEnd);

   DownscalingObserver test("VP8", {{.active = true}, {.active = true}},
                            kLowStartBps,
                            /*automatic_resize=*/false,
                            /*expect_downscale=*/false);
   RunBaseTest(&test);
 }

 TEST_F(QualityScalingTest, AdaptsDownForHighQp_HighestStreamActive_Vp8) {
   // qp_low:1, qp_high:1 -> kHighQp
   test::ScopedKeyValueConfig field_trials(field_trials_,
                                           kPrefix + "1,1,0,0,0,0" + kEnd);

   DownscalingObserver test(
       "VP8", {{.active = false}, {.active = false}, {.active = true}},
       kHighStartBps,
       /*automatic_resize=*/true,
       /*expect_downscale=*/true);
   RunBaseTest(&test);
 }

 TEST_F(QualityScalingTest,
        AdaptsDownForLowStartBitrate_HighestStreamActive_Vp8) {
   // qp_low:1, qp_high:127 -> kNormalQp
   test::ScopedKeyValueConfig field_trials(field_trials_,
                                           kPrefix + "1,127,0,0,0,0" + kEnd);

   DownscalingObserver test(
       "VP8", {{.active = false}, {.active = false}, {.active = true}},
       kSinglecastLimits720pVp8->min_start_bitrate_bps - 1,
       /*automatic_resize=*/true,
       /*expect_downscale=*/true);
   RunBaseTest(&test);
 }

 TEST_F(QualityScalingTest, AdaptsDownButNotUpWithMinStartBitrateLimit) {
   // qp_low:127, qp_high:127 -> kLowQp
   test::ScopedKeyValueConfig field_trials(field_trials_,
                                           kPrefix + "127,127,0,0,0,0" + kEnd);

   UpscalingObserver test("VP8", {{.active = false}, {.active = true}},
                          kSinglecastLimits720pVp8->min_start_bitrate_bps - 1,
                          /*automatic_resize=*/true, /*expect_upscale=*/false);
   RunBaseTest(&test);
 }

 TEST_F(QualityScalingTest, NoAdaptDownForLowStartBitrateIfBitrateEnough_Vp8) {
   // qp_low:1, qp_high:127 -> kNormalQp
   test::ScopedKeyValueConfig field_trials(field_trials_,
                                           kPrefix + "1,127,0,0,0,0" + kEnd);

   DownscalingObserver test(
       "VP8", {{.active = false}, {.active = false}, {.active = true}},
       kSinglecastLimits720pVp8->min_start_bitrate_bps,
       /*automatic_resize=*/true,
       /*expect_downscale=*/false);
   RunBaseTest(&test);
 }

 TEST_F(QualityScalingTest,
        NoAdaptDownForLowStartBitrateIfDefaultLimitsDisabled_Vp8) {
   // qp_low:1, qp_high:127 -> kNormalQp
   test::ScopedKeyValueConfig field_trials(
       field_trials_, kPrefix + "1,127,0,0,0,0" + kEnd +
                          "WebRTC-DefaultBitrateLimitsKillSwitch/Enabled/");

   DownscalingObserver test(
       "VP8", {{.active = false}, {.active = false}, {.active = true}},
       kSinglecastLimits720pVp8->min_start_bitrate_bps - 1,
       /*automatic_resize=*/true,
       /*expect_downscale=*/false);
   RunBaseTest(&test);
 }

 TEST_F(QualityScalingTest,
        NoAdaptDownForLowStartBitrate_OneStreamSinglecastLimitsNotUsed_Vp8) {
   // qp_low:1, qp_high:127 -> kNormalQp
   test::ScopedKeyValueConfig field_trials(field_trials_,
                                           kPrefix + "1,127,0,0,0,0" + kEnd);

   DownscalingObserver test("VP8", {{.active = true}},
                            kSinglecastLimits720pVp8->min_start_bitrate_bps - 1,
                            /*automatic_resize=*/true,
                            /*expect_downscale=*/false);
   RunBaseTest(&test);
 }

 TEST_F(QualityScalingTest, NoAdaptDownForHighQp_LowestStreamActive_Vp8) {
   // qp_low:1, qp_high:1 -> kHighQp
   test::ScopedKeyValueConfig field_trials(field_trials_,
                                           kPrefix + "1,1,0,0,0,0" + kEnd);

   DownscalingObserver test(
       "VP8", {{.active = true}, {.active = false}, {.active = false}},
       kHighStartBps,
       /*automatic_resize=*/true,
       /*expect_downscale=*/false);
   RunBaseTest(&test);
 }

 TEST_F(QualityScalingTest,
        NoAdaptDownForLowStartBitrate_LowestStreamActive_Vp8) {
   // qp_low:1, qp_high:127 -> kNormalQp
   test::ScopedKeyValueConfig field_trials(field_trials_,
                                           kPrefix + "1,127,0,0,0,0" + kEnd);

   DownscalingObserver test(
       "VP8", {{.active = true}, {.active = false}, {.active = false}},
       kLowStartBps,
       /*automatic_resize=*/true,
       /*expect_downscale=*/false);
   RunBaseTest(&test);
 }

 TEST_F(QualityScalingTest, NoAdaptDownForLowStartBitrateIfScalingOff_Vp8) {
   // qp_low:1, qp_high:127 -> kNormalQp
   test::ScopedKeyValueConfig field_trials(field_trials_,
                                           kPrefix + "1,127,0,0,0,0" + kEnd);

   DownscalingObserver test("VP8", {{.active = true}}, kLowStartBps,
                            /*automatic_resize=*/false,
                            /*expect_downscale=*/false);
   RunBaseTest(&test);
 }

 TEST_F(QualityScalingTest, AdaptsDownForHighQp_Vp9) {
   // qp_low:1, qp_high:1 -> kHighQp
   test::ScopedKeyValueConfig field_trials(field_trials_,
                                           kPrefix + "0,0,1,1,0,0" + kEnd);

   DownscalingObserver test("VP9", {{.active = true}}, kHighStartBps,
                            /*automatic_resize=*/true,
                            /*expect_downscale=*/true);
   RunBaseTest(&test);
 }

 TEST_F(QualityScalingTest, NoAdaptDownForHighQpIfScalingOff_Vp9) {
   // qp_low:1, qp_high:1 -> kHighQp
   test::ScopedKeyValueConfig field_trials(
       field_trials_,
       kPrefix + "0,0,1,1,0,0" + kEnd + "WebRTC-VP9QualityScaler/Disabled/");

   DownscalingObserver test("VP9", {{.active = true}}, kHighStartBps,
                            /*automatic_resize=*/true,
                            /*expect_downscale=*/false);
   RunBaseTest(&test);
 }

 TEST_F(QualityScalingTest, AdaptsDownForLowStartBitrate_Vp9) {
   // qp_low:1, qp_high:255 -> kNormalQp
   test::ScopedKeyValueConfig field_trials(field_trials_,
                                           kPrefix + "0,0,1,255,0,0" + kEnd);

   DownscalingObserver test("VP9", {{.active = true}}, kLowStartBps,
                            /*automatic_resize=*/true,
                            /*expect_downscale=*/true);
   RunBaseTest(&test);
 }

 TEST_F(QualityScalingTest, NoAdaptDownForHighQp_LowestStreamActive_Vp9) {
   // qp_low:1, qp_high:1 -> kHighQp
   test::ScopedKeyValueConfig field_trials(field_trials_,
                                           kPrefix + "0,0,1,1,0,0" + kEnd);

   DownscalingObserver test(
       "VP9", {{.active = true}, {.active = false}, {.active = false}},
       kHighStartBps,
       /*automatic_resize=*/true,
       /*expect_downscale=*/false);
   RunBaseTest(&test);
 }

 TEST_F(QualityScalingTest,
        NoAdaptDownForLowStartBitrate_LowestStreamActive_Vp9) {
   // qp_low:1, qp_high:255 -> kNormalQp
   test::ScopedKeyValueConfig field_trials(field_trials_,
                                           kPrefix + "0,0,1,255,0,0" + kEnd);

   DownscalingObserver test(
       "VP9", {{.active = true}, {.active = false}, {.active = false}},
       kLowStartBps,
       /*automatic_resize=*/true,
       /*expect_downscale=*/false);
   RunBaseTest(&test);
 }

 TEST_F(QualityScalingTest, AdaptsDownForHighQp_MiddleStreamActive_Vp9) {
   // qp_low:1, qp_high:1 -> kHighQp
   test::ScopedKeyValueConfig field_trials(field_trials_,
                                           kPrefix + "0,0,1,1,0,0" + kEnd);

   DownscalingObserver test(
       "VP9", {{.active = false}, {.active = true}, {.active = false}},
       kHighStartBps,
       /*automatic_resize=*/true,
       /*expect_downscale=*/true);
   RunBaseTest(&test);
 }

 TEST_F(QualityScalingTest,
        AdaptsDownForLowStartBitrate_MiddleStreamActive_Vp9) {
   // qp_low:1, qp_high:255 -> kNormalQp
   test::ScopedKeyValueConfig field_trials(field_trials_,
                                           kPrefix + "0,0,1,255,0,0" + kEnd);

   DownscalingObserver test(
       "VP9", {{.active = false}, {.active = true}, {.active = false}},
       kSinglecastLimits360pVp9->min_start_bitrate_bps - 1,
       /*automatic_resize=*/true,
       /*expect_downscale=*/true);
   RunBaseTest(&test);
 }

 TEST_F(QualityScalingTest, NoAdaptDownForLowStartBitrateIfBitrateEnough_Vp9) {
   // qp_low:1, qp_high:255 -> kNormalQp
   test::ScopedKeyValueConfig field_trials(field_trials_,
                                           kPrefix + "0,0,1,255,0,0" + kEnd);

   DownscalingObserver test(
       "VP9", {{.active = false}, {.active = true}, {.active = false}},
       kSinglecastLimits360pVp9->min_start_bitrate_bps,
       /*automatic_resize=*/true,
       /*expect_downscale=*/false);
   RunBaseTest(&test);
 }

 TEST_F(QualityScalingTest,
        AdaptsDownButNotUpWithMinStartBitrateLimitWithScalabilityMode_VP9) {
   // qp_low:255, qp_high:255 -> kLowQp
   test::ScopedKeyValueConfig field_trials(field_trials_,
                                           kPrefix + "0,0,255,255,0,0" + kEnd);

   UpscalingObserver test(
       "VP9",
       {{.active = true, .scalability_mode = ScalabilityMode::kL1T3},
        {.active = false}},
       kSinglecastLimits720pVp9->min_start_bitrate_bps - 1,
       /*automatic_resize=*/true, /*expect_upscale=*/false);
   RunBaseTest(&test);
 }

 TEST_F(QualityScalingTest,
        NoAdaptDownForLowStartBitrateIfBitrateEnoughWithScalabilityMode_Vp9) {
   // qp_low:1, qp_high:255 -> kNormalQp
   test::ScopedKeyValueConfig field_trials(field_trials_,
                                           kPrefix + "0,0,1,255,0,0" + kEnd);

   DownscalingObserver test(
       "VP9",
       {{.active = true, .scalability_mode = ScalabilityMode::kL1T3},
        {.active = false},
        {.active = false}},
       kSinglecastLimits720pVp9->min_start_bitrate_bps,
       /*automatic_resize=*/true,
       /*expect_downscale=*/false);
   RunBaseTest(&test);
 }

 #if defined(WEBRTC_USE_H264)
 TEST_F(QualityScalingTest, AdaptsDownForHighQp_H264) {
   // qp_low:1, qp_high:1 -> kHighQp
   test::ScopedKeyValueConfig field_trials(field_trials_,
                                           kPrefix + "0,0,0,0,1,1" + kEnd);

   DownscalingObserver test("H264", {{.active = true}}, kHighStartBps,
                            /*automatic_resize=*/true,
                            /*expect_downscale=*/true);
   RunBaseTest(&test);
 }

 TEST_F(QualityScalingTest, AdaptsDownForLowStartBitrate_H264) {
   // qp_low:1, qp_high:51 -> kNormalQp
   test::ScopedKeyValueConfig field_trials(field_trials_,
                                           kPrefix + "0,0,0,0,1,51" + kEnd);

   DownscalingObserver test("H264", {{.active = true}}, kLowStartBps,
                            /*automatic_resize=*/true,
                            /*expect_downscale=*/true);
   RunBaseTest(&test);
 }
 #endif  // defined(WEBRTC_USE_H264)

 }  // namespace webrtc
	/*
	* Copyright (c) 2018 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 <string>

	#include "api/test/video/function_video_encoder_factory.h"
	#include "media/engine/internal_encoder_factory.h"
	#include "modules/video_coding/codecs/h264/include/h264.h"
	#include "modules/video_coding/codecs/vp8/include/vp8.h"
	#include "modules/video_coding/codecs/vp9/include/vp9.h"
	#include "rtc_base/experiments/encoder_info_settings.h"
	#include "test/call_test.h"
	#include "test/field_trial.h"
	#include "test/frame_generator_capturer.h"

	namespace webrtc {
	namespace {
	constexpr int kInitialWidth = 1280;
	constexpr int kInitialHeight = 720;
	constexpr int kLowStartBps = 100000;
	constexpr int kHighStartBps = 1000000;
	constexpr int kDefaultVgaMinStartBps = 500000; // From video_stream_encoder.cc
	constexpr int kTimeoutMs = 10000; // Some tests are expected to time out.

	void SetEncoderSpecific(VideoEncoderConfig* encoder_config,
	VideoCodecType type,
	bool automatic_resize,
	size_t num_spatial_layers) {
	if (type == kVideoCodecVP8) {
	VideoCodecVP8 vp8 = VideoEncoder::GetDefaultVp8Settings();
	vp8.automaticResizeOn = automatic_resize;
	encoder_config->encoder_specific_settings =
	rtc::make_ref_counted<VideoEncoderConfig::Vp8EncoderSpecificSettings>(
	vp8);
	} else if (type == kVideoCodecVP9) {
	VideoCodecVP9 vp9 = VideoEncoder::GetDefaultVp9Settings();
	vp9.automaticResizeOn = automatic_resize;
	vp9.numberOfSpatialLayers = num_spatial_layers;
	encoder_config->encoder_specific_settings =
	rtc::make_ref_counted<VideoEncoderConfig::Vp9EncoderSpecificSettings>(
	vp9);
	}
	}
	} // namespace

	class QualityScalingTest : public test::CallTest {
	protected:
	const std::string kPrefix = "WebRTC-Video-QualityScaling/Enabled-";
	const std::string kEnd = ",0,0,0.9995,0.9999,1/";
	const absl::optional<VideoEncoder::ResolutionBitrateLimits>
	kSinglecastLimits720pVp8 =
	EncoderInfoSettings::GetDefaultSinglecastBitrateLimitsForResolution(
	kVideoCodecVP8,
	1280 * 720);
	const absl::optional<VideoEncoder::ResolutionBitrateLimits>
	kSinglecastLimits360pVp9 =
	EncoderInfoSettings::GetDefaultSinglecastBitrateLimitsForResolution(
	kVideoCodecVP9,
	640 * 360);
	const absl::optional<VideoEncoder::ResolutionBitrateLimits>
	kSinglecastLimits720pVp9 =
	EncoderInfoSettings::GetDefaultSinglecastBitrateLimitsForResolution(
	kVideoCodecVP9,
	1280 * 720);
	};

	class ScalingObserver : public test::SendTest {
	protected:
	struct TestParams {
	bool active;
	absl::optional<ScalabilityMode> scalability_mode;
	};
	ScalingObserver(const std::string& payload_name,
	const std::vector<TestParams>& test_params,
	int start_bps,
	bool automatic_resize,
	bool expect_scaling)
	: SendTest(expect_scaling ? kTimeoutMs * 4 : kTimeoutMs),
	encoder_factory_(
	[](const SdpVideoFormat& format) -> std::unique_ptr<VideoEncoder> {
	if (format.name == "VP8")
	return VP8Encoder::Create();
	if (format.name == "VP9")
	return VP9Encoder::Create();
	if (format.name == "H264")
	return H264Encoder::Create(cricket::VideoCodec("H264"));
	RTC_DCHECK_NOTREACHED() << format.name;
	return nullptr;
	}),
	payload_name_(payload_name),
	test_params_(test_params),
	start_bps_(start_bps),
	automatic_resize_(automatic_resize),
	expect_scaling_(expect_scaling) {}

	DegradationPreference degradation_preference_ =
	DegradationPreference::MAINTAIN_FRAMERATE;

	private:
	void ModifySenderBitrateConfig(BitrateConstraints* bitrate_config) override {
	bitrate_config->start_bitrate_bps = start_bps_;
	}

	void ModifyVideoDegradationPreference(
	DegradationPreference* degradation_preference) override {
	*degradation_preference = degradation_preference_;
	}

	size_t GetNumVideoStreams() const override {
	return (payload_name_ == "VP9") ? 1 : test_params_.size();
	}

	void ModifyVideoConfigs(
	VideoSendStream::Config* send_config,
	std::vector<VideoReceiveStreamInterface::Config>* receive_configs,
	VideoEncoderConfig* encoder_config) override {
	send_config->encoder_settings.encoder_factory = &encoder_factory_;
	send_config->rtp.payload_name = payload_name_;
	send_config->rtp.payload_type = test::CallTest::kVideoSendPayloadType;
	encoder_config->video_format.name = payload_name_;
	const VideoCodecType codec_type = PayloadStringToCodecType(payload_name_);
	encoder_config->codec_type = codec_type;
	encoder_config->max_bitrate_bps =
	std::max(start_bps_, encoder_config->max_bitrate_bps);
	if (payload_name_ == "VP9") {
	// Simulcast layers indicates which spatial layers are active.
	encoder_config->simulcast_layers.resize(test_params_.size());
	encoder_config->simulcast_layers[0].max_bitrate_bps =
	encoder_config->max_bitrate_bps;
	}
	double scale_factor = 1.0;
	for (int i = test_params_.size() - 1; i >= 0; --i) {
	VideoStream& stream = encoder_config->simulcast_layers[i];
	stream.active = test_params_[i].active;
	stream.scalability_mode = test_params_[i].scalability_mode;
	stream.scale_resolution_down_by = scale_factor;
	scale_factor *= (payload_name_ == "VP9") ? 1.0 : 2.0;
	}
	encoder_config->frame_drop_enabled = true;
	SetEncoderSpecific(encoder_config, codec_type, automatic_resize_,
	test_params_.size());
	}

	void PerformTest() override { EXPECT_EQ(expect_scaling_, Wait()); }

	test::FunctionVideoEncoderFactory encoder_factory_;
	const std::string payload_name_;
	const std::vector<TestParams> test_params_;
	const int start_bps_;
	const bool automatic_resize_;
	const bool expect_scaling_;
	};

	class DownscalingObserver
	: public ScalingObserver,
	public test::FrameGeneratorCapturer::SinkWantsObserver {
	public:
	DownscalingObserver(const std::string& payload_name,
	const std::vector<TestParams>& test_params,
	int start_bps,
	bool automatic_resize,
	bool expect_downscale)
	: ScalingObserver(payload_name,
	test_params,
	start_bps,
	automatic_resize,
	expect_downscale) {}

	private:
	void OnFrameGeneratorCapturerCreated(
	test::FrameGeneratorCapturer* frame_generator_capturer) override {
	frame_generator_capturer->SetSinkWantsObserver(this);
	frame_generator_capturer->ChangeResolution(kInitialWidth, kInitialHeight);
	}

	void OnSinkWantsChanged(rtc::VideoSinkInterface<VideoFrame>* sink,
	const rtc::VideoSinkWants& wants) override {
	if (wants.max_pixel_count < kInitialWidth * kInitialHeight)
	observation_complete_.Set();
	}
	};

	class UpscalingObserver
	: public ScalingObserver,
	public test::FrameGeneratorCapturer::SinkWantsObserver {
	public:
	UpscalingObserver(const std::string& payload_name,
	const std::vector<TestParams>& test_params,
	int start_bps,
	bool automatic_resize,
	bool expect_upscale)
	: ScalingObserver(payload_name,
	test_params,
	start_bps,
	automatic_resize,
	expect_upscale) {}

	void SetDegradationPreference(DegradationPreference preference) {
	degradation_preference_ = preference;
	}

	private:
	void OnFrameGeneratorCapturerCreated(
	test::FrameGeneratorCapturer* frame_generator_capturer) override {
	frame_generator_capturer->SetSinkWantsObserver(this);
	frame_generator_capturer->ChangeResolution(kInitialWidth, kInitialHeight);
	}

	void OnSinkWantsChanged(rtc::VideoSinkInterface<VideoFrame>* sink,
	const rtc::VideoSinkWants& wants) override {
	if (wants.max_pixel_count > last_wants_.max_pixel_count) {
	if (wants.max_pixel_count == std::numeric_limits<int>::max())
	observation_complete_.Set();
	}
	last_wants_ = wants;
	}

	rtc::VideoSinkWants last_wants_;
	};

	TEST_F(QualityScalingTest, AdaptsDownForHighQp_Vp8) {
	// qp_low:1, qp_high:1 -> kHighQp
	test::ScopedKeyValueConfig field_trials(field_trials_,
	kPrefix + "1,1,0,0,0,0" + kEnd);

	DownscalingObserver test("VP8", {{.active = true}}, kHighStartBps,
	/automatic_resize=/true,
	/expect_downscale=/true);
	RunBaseTest(&test);
	}

	TEST_F(QualityScalingTest, NoAdaptDownForHighQpIfScalingOff_Vp8) {
	// qp_low:1, qp_high:1 -> kHighQp
	test::ScopedKeyValueConfig field_trials(field_trials_,
	kPrefix + "1,1,0,0,0,0" + kEnd);

	DownscalingObserver test("VP8", {{.active = true}}, kHighStartBps,
	/automatic_resize=/false,
	/expect_downscale=/false);
	RunBaseTest(&test);
	}

	TEST_F(QualityScalingTest, NoAdaptDownForNormalQp_Vp8) {
	// qp_low:1, qp_high:127 -> kNormalQp
	test::ScopedKeyValueConfig field_trials(field_trials_,
	kPrefix + "1,127,0,0,0,0" + kEnd);

	DownscalingObserver test("VP8", {{.active = true}}, kHighStartBps,
	/automatic_resize=/true,
	/expect_downscale=/false);
	RunBaseTest(&test);
	}

	TEST_F(QualityScalingTest, AdaptsDownForLowStartBitrate_Vp8) {
	// qp_low:1, qp_high:127 -> kNormalQp
	test::ScopedKeyValueConfig field_trials(field_trials_,
	kPrefix + "1,127,0,0,0,0" + kEnd);

	DownscalingObserver test("VP8", {{.active = true}}, kLowStartBps,
	/automatic_resize=/true,
	/expect_downscale=/true);
	RunBaseTest(&test);
	}

	TEST_F(QualityScalingTest, AdaptsDownForLowStartBitrateAndThenUp) {
	// qp_low:127, qp_high:127 -> kLowQp
	test::ScopedKeyValueConfig field_trials(
	field_trials_,
	kPrefix + "127,127,0,0,0,0" + kEnd +
	"WebRTC-Video-BalancedDegradationSettings/"
	"pixels:230400\|921600,fps:20\|30,kbps:300\|500/"); // should not affect

	UpscalingObserver test("VP8", {{.active = true}}, kDefaultVgaMinStartBps - 1,
	/automatic_resize=/true, /expect_upscale=/true);
	RunBaseTest(&test);
	}

	TEST_F(QualityScalingTest, AdaptsDownAndThenUpWithBalanced) {
	// qp_low:127, qp_high:127 -> kLowQp
	test::ScopedKeyValueConfig field_trials(
	field_trials_, kPrefix + "127,127,0,0,0,0" + kEnd +
	"WebRTC-Video-BalancedDegradationSettings/"
	"pixels:230400\|921600,fps:20\|30,kbps:300\|499/");

	UpscalingObserver test("VP8", {{.active = true}}, kDefaultVgaMinStartBps - 1,
	/automatic_resize=/true, /expect_upscale=/true);
	test.SetDegradationPreference(DegradationPreference::BALANCED);
	RunBaseTest(&test);
	}

	TEST_F(QualityScalingTest, AdaptsDownButNotUpWithBalancedIfBitrateNotEnough) {
	// qp_low:127, qp_high:127 -> kLowQp
	test::ScopedKeyValueConfig field_trials(
	field_trials_, kPrefix + "127,127,0,0,0,0" + kEnd +
	"WebRTC-Video-BalancedDegradationSettings/"
	"pixels:230400\|921600,fps:20\|30,kbps:300\|500/");

	UpscalingObserver test("VP8", {{.active = true}}, kDefaultVgaMinStartBps - 1,
	/automatic_resize=/true, /expect_upscale=/false);
	test.SetDegradationPreference(DegradationPreference::BALANCED);
	RunBaseTest(&test);
	}

	TEST_F(QualityScalingTest, NoAdaptDownForLowStartBitrate_Simulcast) {
	// qp_low:1, qp_high:127 -> kNormalQp
	test::ScopedKeyValueConfig field_trials(field_trials_,
	kPrefix + "1,127,0,0,0,0" + kEnd);

	DownscalingObserver test("VP8", {{.active = true}, {.active = true}},
	kLowStartBps,
	/automatic_resize=/false,
	/expect_downscale=/false);
	RunBaseTest(&test);
	}

	TEST_F(QualityScalingTest, AdaptsDownForHighQp_HighestStreamActive_Vp8) {
	// qp_low:1, qp_high:1 -> kHighQp
	test::ScopedKeyValueConfig field_trials(field_trials_,
	kPrefix + "1,1,0,0,0,0" + kEnd);

	DownscalingObserver test(
	"VP8", {{.active = false}, {.active = false}, {.active = true}},
	kHighStartBps,
	/automatic_resize=/true,
	/expect_downscale=/true);
	RunBaseTest(&test);
	}

	TEST_F(QualityScalingTest,
	AdaptsDownForLowStartBitrate_HighestStreamActive_Vp8) {
	// qp_low:1, qp_high:127 -> kNormalQp
	test::ScopedKeyValueConfig field_trials(field_trials_,
	kPrefix + "1,127,0,0,0,0" + kEnd);

	DownscalingObserver test(
	"VP8", {{.active = false}, {.active = false}, {.active = true}},
	kSinglecastLimits720pVp8->min_start_bitrate_bps - 1,
	/automatic_resize=/true,
	/expect_downscale=/true);
	RunBaseTest(&test);
	}

	TEST_F(QualityScalingTest, AdaptsDownButNotUpWithMinStartBitrateLimit) {
	// qp_low:127, qp_high:127 -> kLowQp
	test::ScopedKeyValueConfig field_trials(field_trials_,
	kPrefix + "127,127,0,0,0,0" + kEnd);

	UpscalingObserver test("VP8", {{.active = false}, {.active = true}},
	kSinglecastLimits720pVp8->min_start_bitrate_bps - 1,
	/automatic_resize=/true, /expect_upscale=/false);
	RunBaseTest(&test);
	}

	TEST_F(QualityScalingTest, NoAdaptDownForLowStartBitrateIfBitrateEnough_Vp8) {
	// qp_low:1, qp_high:127 -> kNormalQp
	test::ScopedKeyValueConfig field_trials(field_trials_,
	kPrefix + "1,127,0,0,0,0" + kEnd);

	DownscalingObserver test(
	"VP8", {{.active = false}, {.active = false}, {.active = true}},
	kSinglecastLimits720pVp8->min_start_bitrate_bps,
	/automatic_resize=/true,
	/expect_downscale=/false);
	RunBaseTest(&test);
	}

	TEST_F(QualityScalingTest,
	NoAdaptDownForLowStartBitrateIfDefaultLimitsDisabled_Vp8) {
	// qp_low:1, qp_high:127 -> kNormalQp
	test::ScopedKeyValueConfig field_trials(
	field_trials_, kPrefix + "1,127,0,0,0,0" + kEnd +
	"WebRTC-DefaultBitrateLimitsKillSwitch/Enabled/");

	DownscalingObserver test(
	"VP8", {{.active = false}, {.active = false}, {.active = true}},
	kSinglecastLimits720pVp8->min_start_bitrate_bps - 1,
	/automatic_resize=/true,
	/expect_downscale=/false);
	RunBaseTest(&test);
	}

	TEST_F(QualityScalingTest,
	NoAdaptDownForLowStartBitrate_OneStreamSinglecastLimitsNotUsed_Vp8) {
	// qp_low:1, qp_high:127 -> kNormalQp
	test::ScopedKeyValueConfig field_trials(field_trials_,
	kPrefix + "1,127,0,0,0,0" + kEnd);

	DownscalingObserver test("VP8", {{.active = true}},
	kSinglecastLimits720pVp8->min_start_bitrate_bps - 1,
	/automatic_resize=/true,
	/expect_downscale=/false);
	RunBaseTest(&test);
	}

	TEST_F(QualityScalingTest, NoAdaptDownForHighQp_LowestStreamActive_Vp8) {
	// qp_low:1, qp_high:1 -> kHighQp
	test::ScopedKeyValueConfig field_trials(field_trials_,
	kPrefix + "1,1,0,0,0,0" + kEnd);

	DownscalingObserver test(
	"VP8", {{.active = true}, {.active = false}, {.active = false}},
	kHighStartBps,
	/automatic_resize=/true,
	/expect_downscale=/false);
	RunBaseTest(&test);
	}

	TEST_F(QualityScalingTest,
	NoAdaptDownForLowStartBitrate_LowestStreamActive_Vp8) {
	// qp_low:1, qp_high:127 -> kNormalQp
	test::ScopedKeyValueConfig field_trials(field_trials_,
	kPrefix + "1,127,0,0,0,0" + kEnd);

	DownscalingObserver test(
	"VP8", {{.active = true}, {.active = false}, {.active = false}},
	kLowStartBps,
	/automatic_resize=/true,
	/expect_downscale=/false);
	RunBaseTest(&test);
	}

	TEST_F(QualityScalingTest, NoAdaptDownForLowStartBitrateIfScalingOff_Vp8) {
	// qp_low:1, qp_high:127 -> kNormalQp
	test::ScopedKeyValueConfig field_trials(field_trials_,
	kPrefix + "1,127,0,0,0,0" + kEnd);

	DownscalingObserver test("VP8", {{.active = true}}, kLowStartBps,
	/automatic_resize=/false,
	/expect_downscale=/false);
	RunBaseTest(&test);
	}

	TEST_F(QualityScalingTest, AdaptsDownForHighQp_Vp9) {
	// qp_low:1, qp_high:1 -> kHighQp
	test::ScopedKeyValueConfig field_trials(field_trials_,
	kPrefix + "0,0,1,1,0,0" + kEnd);

	DownscalingObserver test("VP9", {{.active = true}}, kHighStartBps,
	/automatic_resize=/true,
	/expect_downscale=/true);
	RunBaseTest(&test);
	}

	TEST_F(QualityScalingTest, NoAdaptDownForHighQpIfScalingOff_Vp9) {
	// qp_low:1, qp_high:1 -> kHighQp
	test::ScopedKeyValueConfig field_trials(
	field_trials_,
	kPrefix + "0,0,1,1,0,0" + kEnd + "WebRTC-VP9QualityScaler/Disabled/");

	DownscalingObserver test("VP9", {{.active = true}}, kHighStartBps,
	/automatic_resize=/true,
	/expect_downscale=/false);
	RunBaseTest(&test);
	}

	TEST_F(QualityScalingTest, AdaptsDownForLowStartBitrate_Vp9) {
	// qp_low:1, qp_high:255 -> kNormalQp
	test::ScopedKeyValueConfig field_trials(field_trials_,
	kPrefix + "0,0,1,255,0,0" + kEnd);

	DownscalingObserver test("VP9", {{.active = true}}, kLowStartBps,
	/automatic_resize=/true,
	/expect_downscale=/true);
	RunBaseTest(&test);
	}

	TEST_F(QualityScalingTest, NoAdaptDownForHighQp_LowestStreamActive_Vp9) {
	// qp_low:1, qp_high:1 -> kHighQp
	test::ScopedKeyValueConfig field_trials(field_trials_,
	kPrefix + "0,0,1,1,0,0" + kEnd);

	DownscalingObserver test(
	"VP9", {{.active = true}, {.active = false}, {.active = false}},
	kHighStartBps,
	/automatic_resize=/true,
	/expect_downscale=/false);
	RunBaseTest(&test);
	}

	TEST_F(QualityScalingTest,
	NoAdaptDownForLowStartBitrate_LowestStreamActive_Vp9) {
	// qp_low:1, qp_high:255 -> kNormalQp
	test::ScopedKeyValueConfig field_trials(field_trials_,
	kPrefix + "0,0,1,255,0,0" + kEnd);

	DownscalingObserver test(
	"VP9", {{.active = true}, {.active = false}, {.active = false}},
	kLowStartBps,
	/automatic_resize=/true,
	/expect_downscale=/false);
	RunBaseTest(&test);
	}

	TEST_F(QualityScalingTest, AdaptsDownForHighQp_MiddleStreamActive_Vp9) {
	// qp_low:1, qp_high:1 -> kHighQp
	test::ScopedKeyValueConfig field_trials(field_trials_,
	kPrefix + "0,0,1,1,0,0" + kEnd);

	DownscalingObserver test(
	"VP9", {{.active = false}, {.active = true}, {.active = false}},
	kHighStartBps,
	/automatic_resize=/true,
	/expect_downscale=/true);
	RunBaseTest(&test);
	}

	TEST_F(QualityScalingTest,
	AdaptsDownForLowStartBitrate_MiddleStreamActive_Vp9) {
	// qp_low:1, qp_high:255 -> kNormalQp
	test::ScopedKeyValueConfig field_trials(field_trials_,
	kPrefix + "0,0,1,255,0,0" + kEnd);

	DownscalingObserver test(
	"VP9", {{.active = false}, {.active = true}, {.active = false}},
	kSinglecastLimits360pVp9->min_start_bitrate_bps - 1,
	/automatic_resize=/true,
	/expect_downscale=/true);
	RunBaseTest(&test);
	}

	TEST_F(QualityScalingTest, NoAdaptDownForLowStartBitrateIfBitrateEnough_Vp9) {
	// qp_low:1, qp_high:255 -> kNormalQp
	test::ScopedKeyValueConfig field_trials(field_trials_,
	kPrefix + "0,0,1,255,0,0" + kEnd);

	DownscalingObserver test(
	"VP9", {{.active = false}, {.active = true}, {.active = false}},
	kSinglecastLimits360pVp9->min_start_bitrate_bps,
	/automatic_resize=/true,
	/expect_downscale=/false);
	RunBaseTest(&test);
	}

	TEST_F(QualityScalingTest,
	AdaptsDownButNotUpWithMinStartBitrateLimitWithScalabilityMode_VP9) {
	// qp_low:255, qp_high:255 -> kLowQp
	test::ScopedKeyValueConfig field_trials(field_trials_,
	kPrefix + "0,0,255,255,0,0" + kEnd);

	UpscalingObserver test(
	"VP9",
	{{.active = true, .scalability_mode = ScalabilityMode::kL1T3},
	{.active = false}},
	kSinglecastLimits720pVp9->min_start_bitrate_bps - 1,
	/automatic_resize=/true, /expect_upscale=/false);
	RunBaseTest(&test);
	}

	TEST_F(QualityScalingTest,
	NoAdaptDownForLowStartBitrateIfBitrateEnoughWithScalabilityMode_Vp9) {
	// qp_low:1, qp_high:255 -> kNormalQp
	test::ScopedKeyValueConfig field_trials(field_trials_,
	kPrefix + "0,0,1,255,0,0" + kEnd);

	DownscalingObserver test(
	"VP9",
	{{.active = true, .scalability_mode = ScalabilityMode::kL1T3},
	{.active = false},
	{.active = false}},
	kSinglecastLimits720pVp9->min_start_bitrate_bps,
	/automatic_resize=/true,
	/expect_downscale=/false);
	RunBaseTest(&test);
	}

	#if defined(WEBRTC_USE_H264)
	TEST_F(QualityScalingTest, AdaptsDownForHighQp_H264) {
	// qp_low:1, qp_high:1 -> kHighQp
	test::ScopedKeyValueConfig field_trials(field_trials_,
	kPrefix + "0,0,0,0,1,1" + kEnd);

	DownscalingObserver test("H264", {{.active = true}}, kHighStartBps,
	/automatic_resize=/true,
	/expect_downscale=/true);
	RunBaseTest(&test);
	}

	TEST_F(QualityScalingTest, AdaptsDownForLowStartBitrate_H264) {
	// qp_low:1, qp_high:51 -> kNormalQp
	test::ScopedKeyValueConfig field_trials(field_trials_,
	kPrefix + "0,0,0,0,1,51" + kEnd);

	DownscalingObserver test("H264", {{.active = true}}, kLowStartBps,
	/automatic_resize=/true,
	/expect_downscale=/true);
	RunBaseTest(&test);
	}
	#endif // defined(WEBRTC_USE_H264)

	} // namespace webrtc