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webrtc / src / 223cc4b0e7d726fecb8edaafd6e5894791755d8a / . / video / video_stream_encoder.cc
blob: 1c9ad9fbd60f002359477142955a4f37c1f85a49 [file] [log] [blame]
/*
* Copyright (c) 2012 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 <numeric>
#include <utility>
#include "api/video/i420_buffer.h"
#include "common_video/include/video_bitrate_allocator.h"
#include "common_video/include/video_frame.h"
#include "modules/video_coding/include/video_codec_initializer.h"
#include "modules/video_coding/include/video_coding.h"
#include "modules/video_coding/include/video_coding_defines.h"
#include "rtc_base/arraysize.h"
#include "rtc_base/checks.h"
#include "rtc_base/experiments/quality_scaling_experiment.h"
#include "rtc_base/location.h"
#include "rtc_base/logging.h"
#include "rtc_base/system/fallthrough.h"
#include "rtc_base/timeutils.h"
#include "rtc_base/trace_event.h"
#include "video/overuse_frame_detector.h"
#include "video/send_statistics_proxy.h"
namespace webrtc {
namespace {
// Time interval for logging frame counts.
const int64_t kFrameLogIntervalMs = 60000;
const int kMinFramerateFps = 2;
const int kMaxFramerateFps = 120;
// Time to keep a single cached pending frame in paused state.
const int64_t kPendingFrameTimeoutMs = 1000;
// The maximum number of frames to drop at beginning of stream
// to try and achieve desired bitrate.
const int kMaxInitialFramedrop = 4;
// Initial limits for BALANCED degradation preference.
int MinFps(int pixels) {
if (pixels <= 320 * 240) {
return 7;
} else if (pixels <= 480 * 270) {
return 10;
} else if (pixels <= 640 * 480) {
return 15;
} else {
return std::numeric_limits<int>::max();
}
}
int MaxFps(int pixels) {
if (pixels <= 320 * 240) {
return 10;
} else if (pixels <= 480 * 270) {
return 15;
} else {
return std::numeric_limits<int>::max();
}
}
bool IsResolutionScalingEnabled(DegradationPreference degradation_preference) {
return degradation_preference == DegradationPreference::MAINTAIN_FRAMERATE ||
degradation_preference == DegradationPreference::BALANCED;
}
bool IsFramerateScalingEnabled(DegradationPreference degradation_preference) {
return degradation_preference == DegradationPreference::MAINTAIN_RESOLUTION ||
degradation_preference == DegradationPreference::BALANCED;
}
// TODO(pbos): Lower these thresholds (to closer to 100%) when we handle
// pipelining encoders better (multiple input frames before something comes
// out). This should effectively turn off CPU adaptations for systems that
// remotely cope with the load right now.
CpuOveruseOptions GetCpuOveruseOptions(
const VideoSendStream::Config::EncoderSettings& settings,
bool full_overuse_time) {
CpuOveruseOptions options;
if (full_overuse_time) {
options.low_encode_usage_threshold_percent = 150;
options.high_encode_usage_threshold_percent = 200;
}
if (settings.experiment_cpu_load_estimator) {
options.filter_time_ms = 5 * rtc::kNumMillisecsPerSec;
}
return options;
}
} // namespace
// VideoSourceProxy is responsible ensuring thread safety between calls to
// VideoStreamEncoder::SetSource that will happen on libjingle's worker thread
// when a video capturer is connected to the encoder and the encoder task queue
// (encoder_queue_) where the encoder reports its VideoSinkWants.
class VideoStreamEncoder::VideoSourceProxy {
public:
explicit VideoSourceProxy(VideoStreamEncoder* video_stream_encoder)
: video_stream_encoder_(video_stream_encoder),
degradation_preference_(DegradationPreference::DISABLED),
source_(nullptr) {}
void SetSource(rtc::VideoSourceInterface<VideoFrame>* source,
const DegradationPreference& degradation_preference) {
// Called on libjingle's worker thread.
RTC_DCHECK_CALLED_SEQUENTIALLY(&main_checker_);
rtc::VideoSourceInterface<VideoFrame>* old_source = nullptr;
rtc::VideoSinkWants wants;
{
rtc::CritScope lock(&crit_);
degradation_preference_ = degradation_preference;
old_source = source_;
source_ = source;
wants = GetActiveSinkWantsInternal();
}
if (old_source != source && old_source != nullptr) {
old_source->RemoveSink(video_stream_encoder_);
}
if (!source) {
return;
}
source->AddOrUpdateSink(video_stream_encoder_, wants);
}
void SetWantsRotationApplied(bool rotation_applied) {
rtc::CritScope lock(&crit_);
sink_wants_.rotation_applied = rotation_applied;
if (source_)
source_->AddOrUpdateSink(video_stream_encoder_, sink_wants_);
}
rtc::VideoSinkWants GetActiveSinkWants() {
rtc::CritScope lock(&crit_);
return GetActiveSinkWantsInternal();
}
void ResetPixelFpsCount() {
rtc::CritScope lock(&crit_);
sink_wants_.max_pixel_count = std::numeric_limits<int>::max();
sink_wants_.target_pixel_count.reset();
sink_wants_.max_framerate_fps = std::numeric_limits<int>::max();
if (source_)
source_->AddOrUpdateSink(video_stream_encoder_, sink_wants_);
}
bool RequestResolutionLowerThan(int pixel_count,
int min_pixels_per_frame,
bool* min_pixels_reached) {
// Called on the encoder task queue.
rtc::CritScope lock(&crit_);
if (!source_ || !IsResolutionScalingEnabled(degradation_preference_)) {
// This can happen since |degradation_preference_| is set on libjingle's
// worker thread but the adaptation is done on the encoder task queue.
return false;
}
// The input video frame size will have a resolution less than or equal to
// |max_pixel_count| depending on how the source can scale the frame size.
const int pixels_wanted = (pixel_count * 3) / 5;
if (pixels_wanted >= sink_wants_.max_pixel_count) {
return false;
}
if (pixels_wanted < min_pixels_per_frame) {
*min_pixels_reached = true;
return false;
}
RTC_LOG(LS_INFO) << "Scaling down resolution, max pixels: "
<< pixels_wanted;
sink_wants_.max_pixel_count = pixels_wanted;
sink_wants_.target_pixel_count = rtc::nullopt;
source_->AddOrUpdateSink(video_stream_encoder_,
GetActiveSinkWantsInternal());
return true;
}
int RequestFramerateLowerThan(int fps) {
// Called on the encoder task queue.
// The input video frame rate will be scaled down to 2/3, rounding down.
int framerate_wanted = (fps * 2) / 3;
return RestrictFramerate(framerate_wanted) ? framerate_wanted : -1;
}
bool RequestHigherResolutionThan(int pixel_count) {
// Called on the encoder task queue.
rtc::CritScope lock(&crit_);
if (!source_ || !IsResolutionScalingEnabled(degradation_preference_)) {
// This can happen since |degradation_preference_| is set on libjingle's
// worker thread but the adaptation is done on the encoder task queue.
return false;
}
int max_pixels_wanted = pixel_count;
if (max_pixels_wanted != std::numeric_limits<int>::max())
max_pixels_wanted = pixel_count * 4;
if (max_pixels_wanted <= sink_wants_.max_pixel_count)
return false;
sink_wants_.max_pixel_count = max_pixels_wanted;
if (max_pixels_wanted == std::numeric_limits<int>::max()) {
// Remove any constraints.
sink_wants_.target_pixel_count.reset();
} else {
// On step down we request at most 3/5 the pixel count of the previous
// resolution, so in order to take "one step up" we request a resolution
// as close as possible to 5/3 of the current resolution. The actual pixel
// count selected depends on the capabilities of the source. In order to
// not take a too large step up, we cap the requested pixel count to be at
// most four time the current number of pixels.
sink_wants_.target_pixel_count = (pixel_count * 5) / 3;
}
RTC_LOG(LS_INFO) << "Scaling up resolution, max pixels: "
<< max_pixels_wanted;
source_->AddOrUpdateSink(video_stream_encoder_,
GetActiveSinkWantsInternal());
return true;
}
// Request upgrade in framerate. Returns the new requested frame, or -1 if
// no change requested. Note that maxint may be returned if limits due to
// adaptation requests are removed completely. In that case, consider
// |max_framerate_| to be the current limit (assuming the capturer complies).
int RequestHigherFramerateThan(int fps) {
// Called on the encoder task queue.
// The input frame rate will be scaled up to the last step, with rounding.
int framerate_wanted = fps;
if (fps != std::numeric_limits<int>::max())
framerate_wanted = (fps * 3) / 2;
return IncreaseFramerate(framerate_wanted) ? framerate_wanted : -1;
}
bool RestrictFramerate(int fps) {
// Called on the encoder task queue.
rtc::CritScope lock(&crit_);
if (!source_ || !IsFramerateScalingEnabled(degradation_preference_))
return false;
const int fps_wanted = std::max(kMinFramerateFps, fps);
if (fps_wanted >= sink_wants_.max_framerate_fps)
return false;
RTC_LOG(LS_INFO) << "Scaling down framerate: " << fps_wanted;
sink_wants_.max_framerate_fps = fps_wanted;
source_->AddOrUpdateSink(video_stream_encoder_,
GetActiveSinkWantsInternal());
return true;
}
bool IncreaseFramerate(int fps) {
// Called on the encoder task queue.
rtc::CritScope lock(&crit_);
if (!source_ || !IsFramerateScalingEnabled(degradation_preference_))
return false;
const int fps_wanted = std::max(kMinFramerateFps, fps);
if (fps_wanted <= sink_wants_.max_framerate_fps)
return false;
RTC_LOG(LS_INFO) << "Scaling up framerate: " << fps_wanted;
sink_wants_.max_framerate_fps = fps_wanted;
source_->AddOrUpdateSink(video_stream_encoder_,
GetActiveSinkWantsInternal());
return true;
}
private:
rtc::VideoSinkWants GetActiveSinkWantsInternal()
RTC_EXCLUSIVE_LOCKS_REQUIRED(&crit_) {
rtc::VideoSinkWants wants = sink_wants_;
// Clear any constraints from the current sink wants that don't apply to
// the used degradation_preference.
switch (degradation_preference_) {
case DegradationPreference::BALANCED:
break;
case DegradationPreference::MAINTAIN_FRAMERATE:
wants.max_framerate_fps = std::numeric_limits<int>::max();
break;
case DegradationPreference::MAINTAIN_RESOLUTION:
wants.max_pixel_count = std::numeric_limits<int>::max();
wants.target_pixel_count.reset();
break;
case DegradationPreference::DISABLED:
wants.max_pixel_count = std::numeric_limits<int>::max();
wants.target_pixel_count.reset();
wants.max_framerate_fps = std::numeric_limits<int>::max();
}
return wants;
}
rtc::CriticalSection crit_;
rtc::SequencedTaskChecker main_checker_;
VideoStreamEncoder* const video_stream_encoder_;
rtc::VideoSinkWants sink_wants_ RTC_GUARDED_BY(&crit_);
DegradationPreference degradation_preference_ RTC_GUARDED_BY(&crit_);
rtc::VideoSourceInterface<VideoFrame>* source_ RTC_GUARDED_BY(&crit_);
RTC_DISALLOW_COPY_AND_ASSIGN(VideoSourceProxy);
};
VideoStreamEncoder::VideoStreamEncoder(
uint32_t number_of_cores,
SendStatisticsProxy* stats_proxy,
const VideoSendStream::Config::EncoderSettings& settings,
rtc::VideoSinkInterface<VideoFrame>* pre_encode_callback,
std::unique_ptr<OveruseFrameDetector> overuse_detector)
: shutdown_event_(true /* manual_reset */, false),
number_of_cores_(number_of_cores),
initial_rampup_(0),
quality_scaling_experiment_enabled_(QualityScalingExperiment::Enabled()),
source_proxy_(new VideoSourceProxy(this)),
sink_(nullptr),
settings_(settings),
video_sender_(Clock::GetRealTimeClock(), this),
overuse_detector_(std::move(overuse_detector)),
stats_proxy_(stats_proxy),
pre_encode_callback_(pre_encode_callback),
max_framerate_(-1),
pending_encoder_reconfiguration_(false),
pending_encoder_creation_(false),
encoder_start_bitrate_bps_(0),
max_data_payload_length_(0),
last_observed_bitrate_bps_(0),
encoder_paused_and_dropped_frame_(false),
clock_(Clock::GetRealTimeClock()),
degradation_preference_(DegradationPreference::DISABLED),
posted_frames_waiting_for_encode_(0),
last_captured_timestamp_(0),
delta_ntp_internal_ms_(clock_->CurrentNtpInMilliseconds() -
clock_->TimeInMilliseconds()),
last_frame_log_ms_(clock_->TimeInMilliseconds()),
captured_frame_count_(0),
dropped_frame_count_(0),
bitrate_observer_(nullptr),
encoder_queue_("EncoderQueue") {
RTC_DCHECK(stats_proxy);
RTC_DCHECK(overuse_detector_);
}
VideoStreamEncoder::~VideoStreamEncoder() {
RTC_DCHECK_RUN_ON(&thread_checker_);
RTC_DCHECK(shutdown_event_.Wait(0))
<< "Must call ::Stop() before destruction.";
}
void VideoStreamEncoder::Stop() {
RTC_DCHECK_RUN_ON(&thread_checker_);
source_proxy_->SetSource(nullptr, DegradationPreference());
encoder_queue_.PostTask([this] {
RTC_DCHECK_RUN_ON(&encoder_queue_);
overuse_detector_->StopCheckForOveruse();
rate_allocator_.reset();
bitrate_observer_ = nullptr;
video_sender_.RegisterExternalEncoder(nullptr, false);
quality_scaler_ = nullptr;
shutdown_event_.Set();
});
shutdown_event_.Wait(rtc::Event::kForever);
}
void VideoStreamEncoder::SetBitrateAllocationObserver(
VideoBitrateAllocationObserver* bitrate_observer) {
RTC_DCHECK_RUN_ON(&thread_checker_);
encoder_queue_.PostTask([this, bitrate_observer] {
RTC_DCHECK_RUN_ON(&encoder_queue_);
RTC_DCHECK(!bitrate_observer_);
bitrate_observer_ = bitrate_observer;
});
}
void VideoStreamEncoder::SetSource(
rtc::VideoSourceInterface<VideoFrame>* source,
const DegradationPreference& degradation_preference) {
RTC_DCHECK_RUN_ON(&thread_checker_);
source_proxy_->SetSource(source, degradation_preference);
encoder_queue_.PostTask([this, degradation_preference] {
RTC_DCHECK_RUN_ON(&encoder_queue_);
if (degradation_preference_ != degradation_preference) {
// Reset adaptation state, so that we're not tricked into thinking there's
// an already pending request of the same type.
last_adaptation_request_.reset();
if (degradation_preference == DegradationPreference::BALANCED ||
degradation_preference_ == DegradationPreference::BALANCED) {
// TODO(asapersson): Consider removing |adapt_counters_| map and use one
// AdaptCounter for all modes.
source_proxy_->ResetPixelFpsCount();
adapt_counters_.clear();
}
}
degradation_preference_ = degradation_preference;
bool allow_scaling = IsResolutionScalingEnabled(degradation_preference_);
initial_rampup_ = allow_scaling ? 0 : kMaxInitialFramedrop;
if (encoder_)
ConfigureQualityScaler();
if (!IsFramerateScalingEnabled(degradation_preference) &&
max_framerate_ != -1) {
// If frame rate scaling is no longer allowed, remove any potential
// allowance for longer frame intervals.
overuse_detector_->OnTargetFramerateUpdated(max_framerate_);
}
});
}
void VideoStreamEncoder::SetSink(EncoderSink* sink, bool rotation_applied) {
source_proxy_->SetWantsRotationApplied(rotation_applied);
encoder_queue_.PostTask([this, sink] {
RTC_DCHECK_RUN_ON(&encoder_queue_);
sink_ = sink;
});
}
void VideoStreamEncoder::SetStartBitrate(int start_bitrate_bps) {
encoder_queue_.PostTask([this, start_bitrate_bps] {
RTC_DCHECK_RUN_ON(&encoder_queue_);
encoder_start_bitrate_bps_ = start_bitrate_bps;
});
}
void VideoStreamEncoder::ConfigureEncoder(VideoEncoderConfig config,
size_t max_data_payload_length) {
// TODO(srte): This struct should be replaced by a lambda with move capture
// when C++14 lambda is allowed.
struct ConfigureEncoderTask {
void operator()() {
encoder->ConfigureEncoderOnTaskQueue(
std::move(config), max_data_payload_length);
}
VideoStreamEncoder* encoder;
VideoEncoderConfig config;
size_t max_data_payload_length;
};
encoder_queue_.PostTask(ConfigureEncoderTask{
this, std::move(config), max_data_payload_length});
}
void VideoStreamEncoder::ConfigureEncoderOnTaskQueue(
VideoEncoderConfig config,
size_t max_data_payload_length) {
RTC_DCHECK_RUN_ON(&encoder_queue_);
RTC_DCHECK(sink_);
RTC_LOG(LS_INFO) << "ConfigureEncoder requested.";
max_data_payload_length_ = max_data_payload_length;
pending_encoder_creation_ =
(!encoder_ || encoder_config_.video_format != config.video_format);
encoder_config_ = std::move(config);
pending_encoder_reconfiguration_ = true;
// Reconfigure the encoder now if the encoder has an internal source or
// if the frame resolution is known. Otherwise, the reconfiguration is
// deferred until the next frame to minimize the number of reconfigurations.
// The codec configuration depends on incoming video frame size.
if (last_frame_info_) {
ReconfigureEncoder();
} else if (settings_.encoder_factory->QueryVideoEncoder(
encoder_config_.video_format).has_internal_source) {
last_frame_info_ = VideoFrameInfo(176, 144, false);
ReconfigureEncoder();
}
}
// TODO(bugs.webrtc.org/8807): Currently this always does a hard
// reconfiguration, but this isn't always necessary. Add in logic to only update
// the VideoBitrateAllocator and call OnEncoderConfigurationChanged with a
// "soft" reconfiguration.
void VideoStreamEncoder::ReconfigureEncoder() {
RTC_DCHECK(pending_encoder_reconfiguration_);
std::vector<VideoStream> streams =
encoder_config_.video_stream_factory->CreateEncoderStreams(
last_frame_info_->width, last_frame_info_->height, encoder_config_);
// TODO(ilnik): If configured resolution is significantly less than provided,
// e.g. because there are not enough SSRCs for all simulcast streams,
// signal new resolutions via SinkWants to video source.
// Stream dimensions may be not equal to given because of a simulcast
// restrictions.
int highest_stream_width = static_cast<int>(streams.back().width);
int highest_stream_height = static_cast<int>(streams.back().height);
// Dimension may be reduced to be, e.g. divisible by 4.
RTC_CHECK_GE(last_frame_info_->width, highest_stream_width);
RTC_CHECK_GE(last_frame_info_->height, highest_stream_height);
crop_width_ = last_frame_info_->width - highest_stream_width;
crop_height_ = last_frame_info_->height - highest_stream_height;
VideoCodec codec;
if (!VideoCodecInitializer::SetupCodec(
encoder_config_, streams, &codec, &rate_allocator_)) {
RTC_LOG(LS_ERROR) << "Failed to create encoder configuration.";
}
codec.startBitrate =
std::max(encoder_start_bitrate_bps_ / 1000, codec.minBitrate);
codec.startBitrate = std::min(codec.startBitrate, codec.maxBitrate);
codec.expect_encode_from_texture = last_frame_info_->is_texture;
max_framerate_ = codec.maxFramerate;
RTC_DCHECK_LE(max_framerate_, kMaxFramerateFps);
// Keep the same encoder, as long as the video_format is unchanged.
if (pending_encoder_creation_) {
pending_encoder_creation_ = false;
if (encoder_) {
video_sender_.RegisterExternalEncoder(nullptr, false);
}
encoder_ = settings_.encoder_factory->CreateVideoEncoder(
encoder_config_.video_format);
// TODO(nisse): What to do if creating the encoder fails? Crash,
// or just discard incoming frames?
RTC_CHECK(encoder_);
const webrtc::VideoEncoderFactory::CodecInfo info =
settings_.encoder_factory->QueryVideoEncoder(
encoder_config_.video_format);
overuse_detector_->StopCheckForOveruse();
overuse_detector_->StartCheckForOveruse(
GetCpuOveruseOptions(settings_, info.is_hardware_accelerated), this);
video_sender_.RegisterExternalEncoder(encoder_.get(),
info.has_internal_source);
}
// RegisterSendCodec implies an unconditional call to
// encoder_->InitEncode().
bool success = video_sender_.RegisterSendCodec(
&codec, number_of_cores_,
static_cast<uint32_t>(max_data_payload_length_)) == VCM_OK;
if (!success) {
RTC_LOG(LS_ERROR) << "Failed to configure encoder.";
rate_allocator_.reset();
}
video_sender_.UpdateChannelParameters(rate_allocator_.get(),
bitrate_observer_);
// Get the current actual framerate, as measured by the stats proxy. This is
// used to get the correct bitrate layer allocation.
int current_framerate = stats_proxy_->GetSendFrameRate();
if (current_framerate == 0)
current_framerate = codec.maxFramerate;
stats_proxy_->OnEncoderReconfigured(
encoder_config_, streams,
rate_allocator_.get()
? rate_allocator_->GetPreferredBitrateBps(current_framerate)
: codec.maxBitrate);
pending_encoder_reconfiguration_ = false;
sink_->OnEncoderConfigurationChanged(
std::move(streams), encoder_config_.min_transmit_bitrate_bps);
// Get the current target framerate, ie the maximum framerate as specified by
// the current codec configuration, or any limit imposed by cpu adaption in
// maintain-resolution or balanced mode. This is used to make sure overuse
// detection doesn't needlessly trigger in low and/or variable framerate
// scenarios.
int target_framerate = std::min(
max_framerate_, source_proxy_->GetActiveSinkWants().max_framerate_fps);
overuse_detector_->OnTargetFramerateUpdated(target_framerate);
ConfigureQualityScaler();
}
void VideoStreamEncoder::ConfigureQualityScaler() {
RTC_DCHECK_RUN_ON(&encoder_queue_);
const auto scaling_settings = encoder_->GetScalingSettings();
const bool quality_scaling_allowed =
IsResolutionScalingEnabled(degradation_preference_) &&
scaling_settings.thresholds;
if (quality_scaling_allowed) {
if (quality_scaler_.get() == nullptr) {
// Quality scaler has not already been configured.
// Drop frames and scale down until desired quality is achieved.
// Use experimental thresholds if available.
rtc::Optional<VideoEncoder::QpThresholds> experimental_thresholds;
if (quality_scaling_experiment_enabled_) {
experimental_thresholds = QualityScalingExperiment::GetQpThresholds(
encoder_config_.codec_type);
}
// Since the interface is non-public, MakeUnique can't do this upcast.
AdaptationObserverInterface* observer = this;
quality_scaler_ = rtc::MakeUnique<QualityScaler>(
observer, experimental_thresholds ? *experimental_thresholds
: *(scaling_settings.thresholds));
}
} else {
quality_scaler_.reset(nullptr);
initial_rampup_ = kMaxInitialFramedrop;
}
stats_proxy_->SetAdaptationStats(GetActiveCounts(kCpu),
GetActiveCounts(kQuality));
}
void VideoStreamEncoder::OnFrame(const VideoFrame& video_frame) {
RTC_DCHECK_RUNS_SERIALIZED(&incoming_frame_race_checker_);
VideoFrame incoming_frame = video_frame;
// Local time in webrtc time base.
int64_t current_time_us = clock_->TimeInMicroseconds();
int64_t current_time_ms = current_time_us / rtc::kNumMicrosecsPerMillisec;
// In some cases, e.g., when the frame from decoder is fed to encoder,
// the timestamp may be set to the future. As the encoding pipeline assumes
// capture time to be less than present time, we should reset the capture
// timestamps here. Otherwise there may be issues with RTP send stream.
if (incoming_frame.timestamp_us() > current_time_us)
incoming_frame.set_timestamp_us(current_time_us);
// Capture time may come from clock with an offset and drift from clock_.
int64_t capture_ntp_time_ms;
if (video_frame.ntp_time_ms() > 0) {
capture_ntp_time_ms = video_frame.ntp_time_ms();
} else if (video_frame.render_time_ms() != 0) {
capture_ntp_time_ms = video_frame.render_time_ms() + delta_ntp_internal_ms_;
} else {
capture_ntp_time_ms = current_time_ms + delta_ntp_internal_ms_;
}
incoming_frame.set_ntp_time_ms(capture_ntp_time_ms);
// Convert NTP time, in ms, to RTP timestamp.
const int kMsToRtpTimestamp = 90;
incoming_frame.set_timestamp(
kMsToRtpTimestamp * static_cast<uint32_t>(incoming_frame.ntp_time_ms()));
if (incoming_frame.ntp_time_ms() <= last_captured_timestamp_) {
// We don't allow the same capture time for two frames, drop this one.
RTC_LOG(LS_WARNING) << "Same/old NTP timestamp ("
<< incoming_frame.ntp_time_ms()
<< " <= " << last_captured_timestamp_
<< ") for incoming frame. Dropping.";
return;
}
bool log_stats = false;
if (current_time_ms - last_frame_log_ms_ > kFrameLogIntervalMs) {
last_frame_log_ms_ = current_time_ms;
log_stats = true;
}
last_captured_timestamp_ = incoming_frame.ntp_time_ms();
int64_t post_time_us = rtc::TimeMicros();
++posted_frames_waiting_for_encode_;
encoder_queue_.PostTask(
[this, incoming_frame, post_time_us, log_stats]() {
RTC_DCHECK_RUN_ON(&encoder_queue_);
stats_proxy_->OnIncomingFrame(incoming_frame.width(),
incoming_frame.height());
++captured_frame_count_;
const int posted_frames_waiting_for_encode =
posted_frames_waiting_for_encode_.fetch_sub(1);
RTC_DCHECK_GT(posted_frames_waiting_for_encode, 0);
if (posted_frames_waiting_for_encode == 1) {
MaybeEncodeVideoFrame(incoming_frame, post_time_us);
} else {
// There is a newer frame in flight. Do not encode this frame.
RTC_LOG(LS_VERBOSE)
<< "Incoming frame dropped due to that the encoder is blocked.";
++dropped_frame_count_;
stats_proxy_->OnFrameDroppedInEncoderQueue();
}
if (log_stats) {
RTC_LOG(LS_INFO) << "Number of frames: captured "
<< captured_frame_count_
<< ", dropped (due to encoder blocked) "
<< dropped_frame_count_ << ", interval_ms "
<< kFrameLogIntervalMs;
captured_frame_count_ = 0;
dropped_frame_count_ = 0;
}
});
}
void VideoStreamEncoder::OnDiscardedFrame() {
stats_proxy_->OnFrameDroppedBySource();
}
bool VideoStreamEncoder::EncoderPaused() const {
RTC_DCHECK_RUN_ON(&encoder_queue_);
// Pause video if paused by caller or as long as the network is down or the
// pacer queue has grown too large in buffered mode.
// If the pacer queue has grown too large or the network is down,
// last_observed_bitrate_bps_ will be 0.
return last_observed_bitrate_bps_ == 0;
}
void VideoStreamEncoder::TraceFrameDropStart() {
RTC_DCHECK_RUN_ON(&encoder_queue_);
// Start trace event only on the first frame after encoder is paused.
if (!encoder_paused_and_dropped_frame_) {
TRACE_EVENT_ASYNC_BEGIN0("webrtc", "EncoderPaused", this);
}
encoder_paused_and_dropped_frame_ = true;
}
void VideoStreamEncoder::TraceFrameDropEnd() {
RTC_DCHECK_RUN_ON(&encoder_queue_);
// End trace event on first frame after encoder resumes, if frame was dropped.
if (encoder_paused_and_dropped_frame_) {
TRACE_EVENT_ASYNC_END0("webrtc", "EncoderPaused", this);
}
encoder_paused_and_dropped_frame_ = false;
}
void VideoStreamEncoder::MaybeEncodeVideoFrame(const VideoFrame& video_frame,
int64_t time_when_posted_us) {
RTC_DCHECK_RUN_ON(&encoder_queue_);
if (pre_encode_callback_)
pre_encode_callback_->OnFrame(video_frame);
if (!last_frame_info_ || video_frame.width() != last_frame_info_->width ||
video_frame.height() != last_frame_info_->height ||
video_frame.is_texture() != last_frame_info_->is_texture) {
pending_encoder_reconfiguration_ = true;
last_frame_info_ = VideoFrameInfo(video_frame.width(), video_frame.height(),
video_frame.is_texture());
RTC_LOG(LS_INFO) << "Video frame parameters changed: dimensions="
<< last_frame_info_->width << "x"
<< last_frame_info_->height
<< ", texture=" << last_frame_info_->is_texture << ".";
}
// We have to create then encoder before the frame drop logic,
// because the latter depends on encoder_->GetScalingSettings.
// According to the testcase
// InitialFrameDropOffWhenEncoderDisabledScaling, the return value
// from GetScalingSettings should enable or disable the frame drop.
int64_t now_ms = clock_->TimeInMilliseconds();
if (pending_encoder_reconfiguration_) {
ReconfigureEncoder();
last_parameters_update_ms_.emplace(now_ms);
} else if (!last_parameters_update_ms_ ||
now_ms - *last_parameters_update_ms_ >=
vcm::VCMProcessTimer::kDefaultProcessIntervalMs) {
video_sender_.UpdateChannelParameters(rate_allocator_.get(),
bitrate_observer_);
last_parameters_update_ms_.emplace(now_ms);
}
if (DropDueToSize(video_frame.size())) {
RTC_LOG(LS_INFO) << "Dropping frame. Too large for target bitrate.";
int count = GetConstAdaptCounter().ResolutionCount(kQuality);
AdaptDown(kQuality);
if (GetConstAdaptCounter().ResolutionCount(kQuality) > count) {
stats_proxy_->OnInitialQualityResolutionAdaptDown();
}
++initial_rampup_;
// Storing references to a native buffer risks blocking frame capture.
if (video_frame.video_frame_buffer()->type() !=
VideoFrameBuffer::Type::kNative) {
pending_frame_ = video_frame;
pending_frame_post_time_us_ = time_when_posted_us;
} else {
// Ensure that any previously stored frame is dropped.
pending_frame_.reset();
}
return;
}
initial_rampup_ = kMaxInitialFramedrop;
if (EncoderPaused()) {
// Storing references to a native buffer risks blocking frame capture.
if (video_frame.video_frame_buffer()->type() !=
VideoFrameBuffer::Type::kNative) {
if (pending_frame_)
TraceFrameDropStart();
pending_frame_ = video_frame;
pending_frame_post_time_us_ = time_when_posted_us;
} else {
// Ensure that any previously stored frame is dropped.
pending_frame_.reset();
TraceFrameDropStart();
}
return;
}
pending_frame_.reset();
EncodeVideoFrame(video_frame, time_when_posted_us);
}
void VideoStreamEncoder::EncodeVideoFrame(const VideoFrame& video_frame,
int64_t time_when_posted_us) {
RTC_DCHECK_RUN_ON(&encoder_queue_);
TraceFrameDropEnd();
VideoFrame out_frame(video_frame);
// Crop frame if needed.
if (crop_width_ > 0 || crop_height_ > 0) {
int cropped_width = video_frame.width() - crop_width_;
int cropped_height = video_frame.height() - crop_height_;
rtc::scoped_refptr<I420Buffer> cropped_buffer =
I420Buffer::Create(cropped_width, cropped_height);
// TODO(ilnik): Remove scaling if cropping is too big, as it should never
// happen after SinkWants signaled correctly from ReconfigureEncoder.
if (crop_width_ < 4 && crop_height_ < 4) {
cropped_buffer->CropAndScaleFrom(
*video_frame.video_frame_buffer()->ToI420(), crop_width_ / 2,
crop_height_ / 2, cropped_width, cropped_height);
} else {
cropped_buffer->ScaleFrom(
*video_frame.video_frame_buffer()->ToI420().get());
}
out_frame =
VideoFrame(cropped_buffer, video_frame.timestamp(),
video_frame.render_time_ms(), video_frame.rotation());
out_frame.set_ntp_time_ms(video_frame.ntp_time_ms());
}
TRACE_EVENT_ASYNC_STEP0("webrtc", "Video", video_frame.render_time_ms(),
"Encode");
overuse_detector_->FrameCaptured(out_frame, time_when_posted_us);
video_sender_.AddVideoFrame(out_frame, nullptr);
}
void VideoStreamEncoder::SendKeyFrame() {
if (!encoder_queue_.IsCurrent()) {
encoder_queue_.PostTask([this] { SendKeyFrame(); });
return;
}
RTC_DCHECK_RUN_ON(&encoder_queue_);
TRACE_EVENT0("webrtc", "OnKeyFrameRequest");
video_sender_.IntraFrameRequest(0);
}
EncodedImageCallback::Result VideoStreamEncoder::OnEncodedImage(
const EncodedImage& encoded_image,
const CodecSpecificInfo* codec_specific_info,
const RTPFragmentationHeader* fragmentation) {
// Encoded is called on whatever thread the real encoder implementation run
// on. In the case of hardware encoders, there might be several encoders
// running in parallel on different threads.
stats_proxy_->OnSendEncodedImage(encoded_image, codec_specific_info);
EncodedImageCallback::Result result =
sink_->OnEncodedImage(encoded_image, codec_specific_info, fragmentation);
int64_t time_sent_us = rtc::TimeMicros();
uint32_t timestamp = encoded_image._timeStamp;
const int qp = encoded_image.qp_;
int64_t capture_time_us =
encoded_image.capture_time_ms_ * rtc::kNumMicrosecsPerMillisec;
rtc::Optional<int> encode_duration_us;
if (encoded_image.timing_.flags != TimingFrameFlags::kInvalid) {
encode_duration_us.emplace(
// TODO(nisse): Maybe use capture_time_ms_ rather than encode_start_ms_?
rtc::kNumMicrosecsPerMillisec *
(encoded_image.timing_.encode_finish_ms -
encoded_image.timing_.encode_start_ms));
}
encoder_queue_.PostTask(
[this, timestamp, time_sent_us, qp, capture_time_us, encode_duration_us] {
RTC_DCHECK_RUN_ON(&encoder_queue_);
overuse_detector_->FrameSent(timestamp, time_sent_us, capture_time_us,
encode_duration_us);
if (quality_scaler_ && qp >= 0)
quality_scaler_->ReportQp(qp);
});
return result;
}
void VideoStreamEncoder::OnDroppedFrame(DropReason reason) {
switch (reason) {
case DropReason::kDroppedByMediaOptimizations:
stats_proxy_->OnFrameDroppedByMediaOptimizations();
encoder_queue_.PostTask([this] {
RTC_DCHECK_RUN_ON(&encoder_queue_);
if (quality_scaler_)
quality_scaler_->ReportDroppedFrameByMediaOpt();
});
break;
case DropReason::kDroppedByEncoder:
stats_proxy_->OnFrameDroppedByEncoder();
encoder_queue_.PostTask([this] {
RTC_DCHECK_RUN_ON(&encoder_queue_);
if (quality_scaler_)
quality_scaler_->ReportDroppedFrameByEncoder();
});
break;
}
}
void VideoStreamEncoder::OnBitrateUpdated(uint32_t bitrate_bps,
uint8_t fraction_lost,
int64_t round_trip_time_ms) {
if (!encoder_queue_.IsCurrent()) {
encoder_queue_.PostTask(
[this, bitrate_bps, fraction_lost, round_trip_time_ms] {
OnBitrateUpdated(bitrate_bps, fraction_lost, round_trip_time_ms);
});
return;
}
RTC_DCHECK_RUN_ON(&encoder_queue_);
RTC_DCHECK(sink_) << "sink_ must be set before the encoder is active.";
RTC_LOG(LS_VERBOSE) << "OnBitrateUpdated, bitrate " << bitrate_bps
<< " packet loss " << static_cast<int>(fraction_lost)
<< " rtt " << round_trip_time_ms;
video_sender_.SetChannelParameters(bitrate_bps, fraction_lost,
round_trip_time_ms, rate_allocator_.get(),
bitrate_observer_);
encoder_start_bitrate_bps_ =
bitrate_bps != 0 ? bitrate_bps : encoder_start_bitrate_bps_;
bool video_is_suspended = bitrate_bps == 0;
bool video_suspension_changed = video_is_suspended != EncoderPaused();
last_observed_bitrate_bps_ = bitrate_bps;
if (video_suspension_changed) {
RTC_LOG(LS_INFO) << "Video suspend state changed to: "
<< (video_is_suspended ? "suspended" : "not suspended");
stats_proxy_->OnSuspendChange(video_is_suspended);
}
if (video_suspension_changed && !video_is_suspended && pending_frame_ &&
!DropDueToSize(pending_frame_->size())) {
int64_t pending_time_us = rtc::TimeMicros() - pending_frame_post_time_us_;
if (pending_time_us < kPendingFrameTimeoutMs * 1000)
EncodeVideoFrame(*pending_frame_, pending_frame_post_time_us_);
pending_frame_.reset();
}
}
bool VideoStreamEncoder::DropDueToSize(uint32_t pixel_count) const {
if (initial_rampup_ < kMaxInitialFramedrop &&
encoder_start_bitrate_bps_ > 0) {
if (encoder_start_bitrate_bps_ < 300000 /* qvga */) {
return pixel_count > 320 * 240;
} else if (encoder_start_bitrate_bps_ < 500000 /* vga */) {
return pixel_count > 640 * 480;
}
}
return false;
}
void VideoStreamEncoder::AdaptDown(AdaptReason reason) {
RTC_DCHECK_RUN_ON(&encoder_queue_);
AdaptationRequest adaptation_request = {
last_frame_info_->pixel_count(),
stats_proxy_->GetStats().input_frame_rate,
AdaptationRequest::Mode::kAdaptDown};
bool downgrade_requested =
last_adaptation_request_ &&
last_adaptation_request_->mode_ == AdaptationRequest::Mode::kAdaptDown;
switch (degradation_preference_) {
case DegradationPreference::BALANCED:
break;
case DegradationPreference::MAINTAIN_FRAMERATE:
if (downgrade_requested &&
adaptation_request.input_pixel_count_ >=
last_adaptation_request_->input_pixel_count_) {
// Don't request lower resolution if the current resolution is not
// lower than the last time we asked for the resolution to be lowered.
return;
}
break;
case DegradationPreference::MAINTAIN_RESOLUTION:
if (adaptation_request.framerate_fps_ <= 0 ||
(downgrade_requested &&
adaptation_request.framerate_fps_ < kMinFramerateFps)) {
// If no input fps estimate available, can't determine how to scale down
// framerate. Otherwise, don't request lower framerate if we don't have
// a valid frame rate. Since framerate, unlike resolution, is a measure
// we have to estimate, and can fluctuate naturally over time, don't
// make the same kind of limitations as for resolution, but trust the
// overuse detector to not trigger too often.
return;
}
break;
case DegradationPreference::DISABLED:
return;
}
switch (degradation_preference_) {
case DegradationPreference::BALANCED: {
// Try scale down framerate, if lower.
int fps = MinFps(last_frame_info_->pixel_count());
if (source_proxy_->RestrictFramerate(fps)) {
GetAdaptCounter().IncrementFramerate(reason);
break;
}
// Scale down resolution.
RTC_FALLTHROUGH();
}
case DegradationPreference::MAINTAIN_FRAMERATE: {
// Scale down resolution.
bool min_pixels_reached = false;
if (!source_proxy_->RequestResolutionLowerThan(
adaptation_request.input_pixel_count_,
encoder_->GetScalingSettings().min_pixels_per_frame,
&min_pixels_reached)) {
if (min_pixels_reached)
stats_proxy_->OnMinPixelLimitReached();
return;
}
GetAdaptCounter().IncrementResolution(reason);
break;
}
case DegradationPreference::MAINTAIN_RESOLUTION: {
// Scale down framerate.
const int requested_framerate = source_proxy_->RequestFramerateLowerThan(
adaptation_request.framerate_fps_);
if (requested_framerate == -1)
return;
RTC_DCHECK_NE(max_framerate_, -1);
overuse_detector_->OnTargetFramerateUpdated(
std::min(max_framerate_, requested_framerate));
GetAdaptCounter().IncrementFramerate(reason);
break;
}
case DegradationPreference::DISABLED:
RTC_NOTREACHED();
}
last_adaptation_request_.emplace(adaptation_request);
UpdateAdaptationStats(reason);
RTC_LOG(LS_INFO) << GetConstAdaptCounter().ToString();
}
void VideoStreamEncoder::AdaptUp(AdaptReason reason) {
RTC_DCHECK_RUN_ON(&encoder_queue_);
const AdaptCounter& adapt_counter = GetConstAdaptCounter();
int num_downgrades = adapt_counter.TotalCount(reason);
if (num_downgrades == 0)
return;
RTC_DCHECK_GT(num_downgrades, 0);
AdaptationRequest adaptation_request = {
last_frame_info_->pixel_count(),
stats_proxy_->GetStats().input_frame_rate,
AdaptationRequest::Mode::kAdaptUp};
bool adapt_up_requested =
last_adaptation_request_ &&
last_adaptation_request_->mode_ == AdaptationRequest::Mode::kAdaptUp;
if (degradation_preference_ == DegradationPreference::MAINTAIN_FRAMERATE) {
if (adapt_up_requested &&
adaptation_request.input_pixel_count_ <=
last_adaptation_request_->input_pixel_count_) {
// Don't request higher resolution if the current resolution is not
// higher than the last time we asked for the resolution to be higher.
return;
}
}
switch (degradation_preference_) {
case DegradationPreference::BALANCED: {
// Try scale up framerate, if higher.
int fps = MaxFps(last_frame_info_->pixel_count());
if (source_proxy_->IncreaseFramerate(fps)) {
GetAdaptCounter().DecrementFramerate(reason, fps);
// Reset framerate in case of fewer fps steps down than up.
if (adapt_counter.FramerateCount() == 0 &&
fps != std::numeric_limits<int>::max()) {
RTC_LOG(LS_INFO) << "Removing framerate down-scaling setting.";
source_proxy_->IncreaseFramerate(std::numeric_limits<int>::max());
}
break;
}
// Scale up resolution.
RTC_FALLTHROUGH();
}
case DegradationPreference::MAINTAIN_FRAMERATE: {
// Scale up resolution.
int pixel_count = adaptation_request.input_pixel_count_;
if (adapt_counter.ResolutionCount() == 1) {
RTC_LOG(LS_INFO) << "Removing resolution down-scaling setting.";
pixel_count = std::numeric_limits<int>::max();
}
if (!source_proxy_->RequestHigherResolutionThan(pixel_count))
return;
GetAdaptCounter().DecrementResolution(reason);
break;
}
case DegradationPreference::MAINTAIN_RESOLUTION: {
// Scale up framerate.
int fps = adaptation_request.framerate_fps_;
if (adapt_counter.FramerateCount() == 1) {
RTC_LOG(LS_INFO) << "Removing framerate down-scaling setting.";
fps = std::numeric_limits<int>::max();
}
const int requested_framerate =
source_proxy_->RequestHigherFramerateThan(fps);
if (requested_framerate == -1) {
overuse_detector_->OnTargetFramerateUpdated(max_framerate_);
return;
}
overuse_detector_->OnTargetFramerateUpdated(
std::min(max_framerate_, requested_framerate));
GetAdaptCounter().DecrementFramerate(reason);
break;
}
case DegradationPreference::DISABLED:
return;
}
last_adaptation_request_.emplace(adaptation_request);
UpdateAdaptationStats(reason);
RTC_LOG(LS_INFO) << adapt_counter.ToString();
}
void VideoStreamEncoder::UpdateAdaptationStats(AdaptReason reason) {
switch (reason) {
case kCpu:
stats_proxy_->OnCpuAdaptationChanged(GetActiveCounts(kCpu),
GetActiveCounts(kQuality));
break;
case kQuality:
stats_proxy_->OnQualityAdaptationChanged(GetActiveCounts(kCpu),
GetActiveCounts(kQuality));
break;
}
}
VideoStreamEncoder::AdaptCounts VideoStreamEncoder::GetActiveCounts(
AdaptReason reason) {
VideoStreamEncoder::AdaptCounts counts =
GetConstAdaptCounter().Counts(reason);
switch (reason) {
case kCpu:
if (!IsFramerateScalingEnabled(degradation_preference_))
counts.fps = -1;
if (!IsResolutionScalingEnabled(degradation_preference_))
counts.resolution = -1;
break;
case kQuality:
if (!IsFramerateScalingEnabled(degradation_preference_) ||
!quality_scaler_) {
counts.fps = -1;
}
if (!IsResolutionScalingEnabled(degradation_preference_) ||
!quality_scaler_) {
counts.resolution = -1;
}
break;
}
return counts;
}
VideoStreamEncoder::AdaptCounter& VideoStreamEncoder::GetAdaptCounter() {
return adapt_counters_[degradation_preference_];
}
const VideoStreamEncoder::AdaptCounter&
VideoStreamEncoder::GetConstAdaptCounter() {
return adapt_counters_[degradation_preference_];
}
// Class holding adaptation information.
VideoStreamEncoder::AdaptCounter::AdaptCounter() {
fps_counters_.resize(kScaleReasonSize);
resolution_counters_.resize(kScaleReasonSize);
static_assert(kScaleReasonSize == 2, "Update MoveCount.");
}
VideoStreamEncoder::AdaptCounter::~AdaptCounter() {}
std::string VideoStreamEncoder::AdaptCounter::ToString() const {
std::stringstream ss;
ss << "Downgrade counts: fps: {" << ToString(fps_counters_);
ss << "}, resolution: {" << ToString(resolution_counters_) << "}";
return ss.str();
}
VideoStreamEncoder::AdaptCounts VideoStreamEncoder::AdaptCounter::Counts(
int reason) const {
AdaptCounts counts;
counts.fps = fps_counters_[reason];
counts.resolution = resolution_counters_[reason];
return counts;
}
void VideoStreamEncoder::AdaptCounter::IncrementFramerate(int reason) {
++(fps_counters_[reason]);
}
void VideoStreamEncoder::AdaptCounter::IncrementResolution(int reason) {
++(resolution_counters_[reason]);
}
void VideoStreamEncoder::AdaptCounter::DecrementFramerate(int reason) {
if (fps_counters_[reason] == 0) {
// Balanced mode: Adapt up is in a different order, switch reason.
// E.g. framerate adapt down: quality (2), framerate adapt up: cpu (3).
// 1. Down resolution (cpu): res={quality:0,cpu:1}, fps={quality:0,cpu:0}
// 2. Down fps (quality): res={quality:0,cpu:1}, fps={quality:1,cpu:0}
// 3. Up fps (cpu): res={quality:1,cpu:0}, fps={quality:0,cpu:0}
// 4. Up resolution (quality): res={quality:0,cpu:0}, fps={quality:0,cpu:0}
RTC_DCHECK_GT(TotalCount(reason), 0) << "No downgrade for reason.";
RTC_DCHECK_GT(FramerateCount(), 0) << "Framerate not downgraded.";
MoveCount(&resolution_counters_, reason);
MoveCount(&fps_counters_, (reason + 1) % kScaleReasonSize);
}
--(fps_counters_[reason]);
RTC_DCHECK_GE(fps_counters_[reason], 0);
}
void VideoStreamEncoder::AdaptCounter::DecrementResolution(int reason) {
if (resolution_counters_[reason] == 0) {
// Balanced mode: Adapt up is in a different order, switch reason.
RTC_DCHECK_GT(TotalCount(reason), 0) << "No downgrade for reason.";
RTC_DCHECK_GT(ResolutionCount(), 0) << "Resolution not downgraded.";
MoveCount(&fps_counters_, reason);
MoveCount(&resolution_counters_, (reason + 1) % kScaleReasonSize);
}
--(resolution_counters_[reason]);
RTC_DCHECK_GE(resolution_counters_[reason], 0);
}
void VideoStreamEncoder::AdaptCounter::DecrementFramerate(int reason,
int cur_fps) {
DecrementFramerate(reason);
// Reset if at max fps (i.e. in case of fewer steps up than down).
if (cur_fps == std::numeric_limits<int>::max())
std::fill(fps_counters_.begin(), fps_counters_.end(), 0);
}
int VideoStreamEncoder::AdaptCounter::FramerateCount() const {
return Count(fps_counters_);
}
int VideoStreamEncoder::AdaptCounter::ResolutionCount() const {
return Count(resolution_counters_);
}
int VideoStreamEncoder::AdaptCounter::FramerateCount(int reason) const {
return fps_counters_[reason];
}
int VideoStreamEncoder::AdaptCounter::ResolutionCount(int reason) const {
return resolution_counters_[reason];
}
int VideoStreamEncoder::AdaptCounter::TotalCount(int reason) const {
return FramerateCount(reason) + ResolutionCount(reason);
}
int VideoStreamEncoder::AdaptCounter::Count(
const std::vector<int>& counters) const {
return std::accumulate(counters.begin(), counters.end(), 0);
}
void VideoStreamEncoder::AdaptCounter::MoveCount(std::vector<int>* counters,
int from_reason) {
int to_reason = (from_reason + 1) % kScaleReasonSize;
++((*counters)[to_reason]);
--((*counters)[from_reason]);
}
std::string VideoStreamEncoder::AdaptCounter::ToString(
const std::vector<int>& counters) const {
std::stringstream ss;
for (size_t reason = 0; reason < kScaleReasonSize; ++reason) {
ss << (reason ? " cpu" : "quality") << ":" << counters[reason];
}
return ss.str();
}
} // namespace webrtc