video/frame_encode_metadata_writer.cc - src - Git at Google

 /*
  *  Copyright (c) 2019 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/frame_encode_metadata_writer.h"

 #include <algorithm>
 #include <utility>

 #include "absl/memory/memory.h"
 #include "common_video/h264/sps_vui_rewriter.h"
 #include "modules/include/module_common_types_public.h"
 #include "modules/video_coding/include/video_coding_defines.h"
 #include "rtc_base/logging.h"
 #include "rtc_base/ref_counted_object.h"
 #include "rtc_base/time_utils.h"

 namespace webrtc {
 namespace {
 const int kMessagesThrottlingThreshold = 2;
 const int kThrottleRatio = 100000;

 class EncodedImageBufferWrapper : public EncodedImageBufferInterface {
  public:
   explicit EncodedImageBufferWrapper(rtc::Buffer&& buffer)
       : buffer_(std::move(buffer)) {}

   const uint8_t* data() const override { return buffer_.data(); }
   uint8_t* data() override { return buffer_.data(); }
   size_t size() const override { return buffer_.size(); }

   void Realloc(size_t t) override { RTC_NOTREACHED(); }

  private:
   rtc::Buffer buffer_;
 };

 }  // namespace

 FrameEncodeMetadataWriter::TimingFramesLayerInfo::TimingFramesLayerInfo() =
     default;
 FrameEncodeMetadataWriter::TimingFramesLayerInfo::~TimingFramesLayerInfo() =
     default;

 FrameEncodeMetadataWriter::FrameEncodeMetadataWriter(
     EncodedImageCallback* frame_drop_callback)
     : frame_drop_callback_(frame_drop_callback),
       internal_source_(false),
       framerate_fps_(0),
       last_timing_frame_time_ms_(-1),
       reordered_frames_logged_messages_(0),
       stalled_encoder_logged_messages_(0) {
   codec_settings_.timing_frame_thresholds = {-1, 0};
 }
 FrameEncodeMetadataWriter::~FrameEncodeMetadataWriter() {}

 void FrameEncodeMetadataWriter::OnEncoderInit(const VideoCodec& codec,
                                               bool internal_source) {
   rtc::CritScope cs(&lock_);
   codec_settings_ = codec;
   internal_source_ = internal_source;
 }

 void FrameEncodeMetadataWriter::OnSetRates(
     const VideoBitrateAllocation& bitrate_allocation,
     uint32_t framerate_fps) {
   rtc::CritScope cs(&lock_);
   framerate_fps_ = framerate_fps;
   const size_t num_spatial_layers = NumSpatialLayers();
   if (timing_frames_info_.size() < num_spatial_layers) {
     timing_frames_info_.resize(num_spatial_layers);
   }
   for (size_t i = 0; i < num_spatial_layers; ++i) {
     timing_frames_info_[i].target_bitrate_bytes_per_sec =
         bitrate_allocation.GetSpatialLayerSum(i) / 8;
   }
 }

 void FrameEncodeMetadataWriter::OnEncodeStarted(const VideoFrame& frame) {
   rtc::CritScope cs(&lock_);
   if (internal_source_) {
     return;
   }

   const size_t num_spatial_layers = NumSpatialLayers();
   timing_frames_info_.resize(num_spatial_layers);
   FrameMetadata metadata;
   metadata.rtp_timestamp = frame.timestamp();
   metadata.encode_start_time_ms = rtc::TimeMillis();
   metadata.ntp_time_ms = frame.ntp_time_ms();
   metadata.timestamp_us = frame.timestamp_us();
   metadata.rotation = frame.rotation();
   metadata.color_space = frame.color_space();
   metadata.packet_infos = frame.packet_infos();
   for (size_t si = 0; si < num_spatial_layers; ++si) {
     RTC_DCHECK(timing_frames_info_[si].frames.empty() ||
                rtc::TimeDiff(
                    frame.render_time_ms(),
                    timing_frames_info_[si].frames.back().timestamp_us / 1000) >=
                    0);
     // If stream is disabled due to low bandwidth OnEncodeStarted still will be
     // called and have to be ignored.
     if (timing_frames_info_[si].target_bitrate_bytes_per_sec == 0)
       return;
     if (timing_frames_info_[si].frames.size() == kMaxEncodeStartTimeListSize) {
       ++stalled_encoder_logged_messages_;
       if (stalled_encoder_logged_messages_ <= kMessagesThrottlingThreshold ||
           stalled_encoder_logged_messages_ % kThrottleRatio == 0) {
         RTC_LOG(LS_WARNING) << "Too many frames in the encode_start_list."
                                " Did encoder stall?";
         if (stalled_encoder_logged_messages_ == kMessagesThrottlingThreshold) {
           RTC_LOG(LS_WARNING)
               << "Too many log messages. Further stalled encoder"
                  "warnings will be throttled.";
         }
       }
       frame_drop_callback_->OnDroppedFrame(
           EncodedImageCallback::DropReason::kDroppedByEncoder);
       timing_frames_info_[si].frames.pop_front();
     }
     timing_frames_info_[si].frames.emplace_back(metadata);
   }
 }

 void FrameEncodeMetadataWriter::FillTimingInfo(size_t simulcast_svc_idx,
                                                EncodedImage* encoded_image) {
   rtc::CritScope cs(&lock_);
   absl::optional<size_t> outlier_frame_size;
   absl::optional<int64_t> encode_start_ms;
   uint8_t timing_flags = VideoSendTiming::kNotTriggered;

   int64_t encode_done_ms = rtc::TimeMillis();

   // Encoders with internal sources do not call OnEncodeStarted
   // |timing_frames_info_| may be not filled here.
   if (!internal_source_) {
     encode_start_ms =
         ExtractEncodeStartTimeAndFillMetadata(simulcast_svc_idx, encoded_image);
   }

   if (timing_frames_info_.size() > simulcast_svc_idx) {
     size_t target_bitrate =
         timing_frames_info_[simulcast_svc_idx].target_bitrate_bytes_per_sec;
     if (framerate_fps_ > 0 && target_bitrate > 0) {
       // framerate and target bitrate were reported by encoder.
       size_t average_frame_size = target_bitrate / framerate_fps_;
       outlier_frame_size.emplace(
           average_frame_size *
           codec_settings_.timing_frame_thresholds.outlier_ratio_percent / 100);
     }
   }

   // Outliers trigger timing frames, but do not affect scheduled timing
   // frames.
   if (outlier_frame_size && encoded_image->size() >= *outlier_frame_size) {
     timing_flags |= VideoSendTiming::kTriggeredBySize;
   }

   // Check if it's time to send a timing frame.
   int64_t timing_frame_delay_ms =
       encoded_image->capture_time_ms_ - last_timing_frame_time_ms_;
   // Trigger threshold if it's a first frame, too long passed since the last
   // timing frame, or we already sent timing frame on a different simulcast
   // stream with the same capture time.
   if (last_timing_frame_time_ms_ == -1 ||
       timing_frame_delay_ms >=
           codec_settings_.timing_frame_thresholds.delay_ms ||
       timing_frame_delay_ms == 0) {
     timing_flags |= VideoSendTiming::kTriggeredByTimer;
     last_timing_frame_time_ms_ = encoded_image->capture_time_ms_;
   }

   // Workaround for chromoting encoder: it passes encode start and finished
   // timestamps in |timing_| field, but they (together with capture timestamp)
   // are not in the WebRTC clock.
   if (internal_source_ && encoded_image->timing_.encode_finish_ms > 0 &&
       encoded_image->timing_.encode_start_ms > 0) {
     int64_t clock_offset_ms =
         encode_done_ms - encoded_image->timing_.encode_finish_ms;
     // Translate capture timestamp to local WebRTC clock.
     encoded_image->capture_time_ms_ += clock_offset_ms;
     encoded_image->SetTimestamp(
         static_cast<uint32_t>(encoded_image->capture_time_ms_ * 90));
     encode_start_ms.emplace(encoded_image->timing_.encode_start_ms +
                             clock_offset_ms);
   }

   // If encode start is not available that means that encoder uses internal
   // source. In that case capture timestamp may be from a different clock with a
   // drift relative to rtc::TimeMillis(). We can't use it for Timing frames,
   // because to being sent in the network capture time required to be less than
   // all the other timestamps.
   if (encode_start_ms) {
     encoded_image->SetEncodeTime(*encode_start_ms, encode_done_ms);
     encoded_image->timing_.flags = timing_flags;
   } else {
     encoded_image->timing_.flags = VideoSendTiming::kInvalid;
   }
 }

 std::unique_ptr<RTPFragmentationHeader>
 FrameEncodeMetadataWriter::UpdateBitstream(
     const CodecSpecificInfo* codec_specific_info,
     const RTPFragmentationHeader* fragmentation,
     EncodedImage* encoded_image) {
   if (!codec_specific_info ||
       codec_specific_info->codecType != kVideoCodecH264 || !fragmentation ||
       encoded_image->_frameType != VideoFrameType::kVideoFrameKey) {
     return nullptr;
   }

   rtc::Buffer modified_buffer;
   std::unique_ptr<RTPFragmentationHeader> modified_fragmentation =
       absl::make_unique<RTPFragmentationHeader>();
   modified_fragmentation->CopyFrom(*fragmentation);

   // Make sure that the data is not copied if owned by EncodedImage.
   const EncodedImage& buffer = *encoded_image;
   SpsVuiRewriter::ParseOutgoingBitstreamAndRewriteSps(
       buffer, fragmentation->fragmentationVectorSize,
       fragmentation->fragmentationOffset, fragmentation->fragmentationLength,
       encoded_image->ColorSpace(), &modified_buffer,
       modified_fragmentation->fragmentationOffset,
       modified_fragmentation->fragmentationLength);

   encoded_image->SetEncodedData(
       new rtc::RefCountedObject<EncodedImageBufferWrapper>(
           std::move(modified_buffer)));

   return modified_fragmentation;
 }

 void FrameEncodeMetadataWriter::Reset() {
   rtc::CritScope cs(&lock_);
   for (auto& info : timing_frames_info_) {
     info.frames.clear();
   }
   last_timing_frame_time_ms_ = -1;
   reordered_frames_logged_messages_ = 0;
   stalled_encoder_logged_messages_ = 0;
 }

 absl::optional<int64_t>
 FrameEncodeMetadataWriter::ExtractEncodeStartTimeAndFillMetadata(
     size_t simulcast_svc_idx,
     EncodedImage* encoded_image) {
   absl::optional<int64_t> result;
   size_t num_simulcast_svc_streams = timing_frames_info_.size();
   if (simulcast_svc_idx < num_simulcast_svc_streams) {
     auto metadata_list = &timing_frames_info_[simulcast_svc_idx].frames;
     // Skip frames for which there was OnEncodeStarted but no OnEncodedImage
     // call. These are dropped by encoder internally.
     // Because some hardware encoders don't preserve capture timestamp we
     // use RTP timestamps here.
     while (!metadata_list->empty() &&
            IsNewerTimestamp(encoded_image->Timestamp(),
                             metadata_list->front().rtp_timestamp)) {
       frame_drop_callback_->OnDroppedFrame(
           EncodedImageCallback::DropReason::kDroppedByEncoder);
       metadata_list->pop_front();
     }

     encoded_image->content_type_ =
         (codec_settings_.mode == VideoCodecMode::kScreensharing)
             ? VideoContentType::SCREENSHARE
             : VideoContentType::UNSPECIFIED;

     if (!metadata_list->empty() &&
         metadata_list->front().rtp_timestamp == encoded_image->Timestamp()) {
       result.emplace(metadata_list->front().encode_start_time_ms);
       encoded_image->capture_time_ms_ =
           metadata_list->front().timestamp_us / 1000;
       encoded_image->ntp_time_ms_ = metadata_list->front().ntp_time_ms;
       encoded_image->rotation_ = metadata_list->front().rotation;
       encoded_image->SetColorSpace(metadata_list->front().color_space);
       encoded_image->SetPacketInfos(metadata_list->front().packet_infos);
       metadata_list->pop_front();
     } else {
       ++reordered_frames_logged_messages_;
       if (reordered_frames_logged_messages_ <= kMessagesThrottlingThreshold ||
           reordered_frames_logged_messages_ % kThrottleRatio == 0) {
         RTC_LOG(LS_WARNING) << "Frame with no encode started time recordings. "
                                "Encoder may be reordering frames "
                                "or not preserving RTP timestamps.";
         if (reordered_frames_logged_messages_ == kMessagesThrottlingThreshold) {
           RTC_LOG(LS_WARNING) << "Too many log messages. Further frames "
                                  "reordering warnings will be throttled.";
         }
       }
     }
   }
   return result;
 }

 size_t FrameEncodeMetadataWriter::NumSpatialLayers() const {
   size_t num_spatial_layers = codec_settings_.numberOfSimulcastStreams;
   if (codec_settings_.codecType == kVideoCodecVP9) {
     num_spatial_layers = std::max(
         num_spatial_layers,
         static_cast<size_t>(codec_settings_.VP9().numberOfSpatialLayers));
   }
   return std::max(num_spatial_layers, size_t{1});
 }

 }  // namespace webrtc
	/*
	* Copyright (c) 2019 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/frame_encode_metadata_writer.h"

	#include <algorithm>
	#include <utility>

	#include "absl/memory/memory.h"
	#include "common_video/h264/sps_vui_rewriter.h"
	#include "modules/include/module_common_types_public.h"
	#include "modules/video_coding/include/video_coding_defines.h"
	#include "rtc_base/logging.h"
	#include "rtc_base/ref_counted_object.h"
	#include "rtc_base/time_utils.h"

	namespace webrtc {
	namespace {
	const int kMessagesThrottlingThreshold = 2;
	const int kThrottleRatio = 100000;

	class EncodedImageBufferWrapper : public EncodedImageBufferInterface {
	public:
	explicit EncodedImageBufferWrapper(rtc::Buffer&& buffer)
	: buffer_(std::move(buffer)) {}

	const uint8_t* data() const override { return buffer_.data(); }
	uint8_t* data() override { return buffer_.data(); }
	size_t size() const override { return buffer_.size(); }

	void Realloc(size_t t) override { RTC_NOTREACHED(); }

	private:
	rtc::Buffer buffer_;
	};

	} // namespace

	FrameEncodeMetadataWriter::TimingFramesLayerInfo::TimingFramesLayerInfo() =
	default;
	FrameEncodeMetadataWriter::TimingFramesLayerInfo::~TimingFramesLayerInfo() =
	default;

	FrameEncodeMetadataWriter::FrameEncodeMetadataWriter(
	EncodedImageCallback* frame_drop_callback)
	: frame_drop_callback_(frame_drop_callback),
	internal_source_(false),
	framerate_fps_(0),
	last_timing_frame_time_ms_(-1),
	reordered_frames_logged_messages_(0),
	stalled_encoder_logged_messages_(0) {
	codec_settings_.timing_frame_thresholds = {-1, 0};
	}
	FrameEncodeMetadataWriter::~FrameEncodeMetadataWriter() {}

	void FrameEncodeMetadataWriter::OnEncoderInit(const VideoCodec& codec,
	bool internal_source) {
	rtc::CritScope cs(&lock_);
	codec_settings_ = codec;
	internal_source_ = internal_source;
	}

	void FrameEncodeMetadataWriter::OnSetRates(
	const VideoBitrateAllocation& bitrate_allocation,
	uint32_t framerate_fps) {
	rtc::CritScope cs(&lock_);
	framerate_fps_ = framerate_fps;
	const size_t num_spatial_layers = NumSpatialLayers();
	if (timing_frames_info_.size() < num_spatial_layers) {
	timing_frames_info_.resize(num_spatial_layers);
	}
	for (size_t i = 0; i < num_spatial_layers; ++i) {
	timing_frames_info_[i].target_bitrate_bytes_per_sec =
	bitrate_allocation.GetSpatialLayerSum(i) / 8;
	}
	}

	void FrameEncodeMetadataWriter::OnEncodeStarted(const VideoFrame& frame) {
	rtc::CritScope cs(&lock_);
	if (internal_source_) {
	return;
	}

	const size_t num_spatial_layers = NumSpatialLayers();
	timing_frames_info_.resize(num_spatial_layers);
	FrameMetadata metadata;
	metadata.rtp_timestamp = frame.timestamp();
	metadata.encode_start_time_ms = rtc::TimeMillis();
	metadata.ntp_time_ms = frame.ntp_time_ms();
	metadata.timestamp_us = frame.timestamp_us();
	metadata.rotation = frame.rotation();
	metadata.color_space = frame.color_space();
	metadata.packet_infos = frame.packet_infos();
	for (size_t si = 0; si < num_spatial_layers; ++si) {
	RTC_DCHECK(timing_frames_info_[si].frames.empty() \|\|
	rtc::TimeDiff(
	frame.render_time_ms(),
	timing_frames_info_[si].frames.back().timestamp_us / 1000) >=
	0);
	// If stream is disabled due to low bandwidth OnEncodeStarted still will be
	// called and have to be ignored.
	if (timing_frames_info_[si].target_bitrate_bytes_per_sec == 0)
	return;
	if (timing_frames_info_[si].frames.size() == kMaxEncodeStartTimeListSize) {
	++stalled_encoder_logged_messages_;
	if (stalled_encoder_logged_messages_ <= kMessagesThrottlingThreshold \|\|
	stalled_encoder_logged_messages_ % kThrottleRatio == 0) {
	RTC_LOG(LS_WARNING) << "Too many frames in the encode_start_list."
	" Did encoder stall?";
	if (stalled_encoder_logged_messages_ == kMessagesThrottlingThreshold) {
	RTC_LOG(LS_WARNING)
	<< "Too many log messages. Further stalled encoder"
	"warnings will be throttled.";
	}
	}
	frame_drop_callback_->OnDroppedFrame(
	EncodedImageCallback::DropReason::kDroppedByEncoder);
	timing_frames_info_[si].frames.pop_front();
	}
	timing_frames_info_[si].frames.emplace_back(metadata);
	}
	}

	void FrameEncodeMetadataWriter::FillTimingInfo(size_t simulcast_svc_idx,
	EncodedImage* encoded_image) {
	rtc::CritScope cs(&lock_);
	absl::optional<size_t> outlier_frame_size;
	absl::optional<int64_t> encode_start_ms;
	uint8_t timing_flags = VideoSendTiming::kNotTriggered;

	int64_t encode_done_ms = rtc::TimeMillis();

	// Encoders with internal sources do not call OnEncodeStarted
	// \|timing_frames_info_\| may be not filled here.
	if (!internal_source_) {
	encode_start_ms =
	ExtractEncodeStartTimeAndFillMetadata(simulcast_svc_idx, encoded_image);
	}

	if (timing_frames_info_.size() > simulcast_svc_idx) {
	size_t target_bitrate =
	timing_frames_info_[simulcast_svc_idx].target_bitrate_bytes_per_sec;
	if (framerate_fps_ > 0 && target_bitrate > 0) {
	// framerate and target bitrate were reported by encoder.
	size_t average_frame_size = target_bitrate / framerate_fps_;
	outlier_frame_size.emplace(
	average_frame_size *
	codec_settings_.timing_frame_thresholds.outlier_ratio_percent / 100);
	}
	}

	// Outliers trigger timing frames, but do not affect scheduled timing
	// frames.
	if (outlier_frame_size && encoded_image->size() >= *outlier_frame_size) {
	timing_flags \|= VideoSendTiming::kTriggeredBySize;
	}

	// Check if it's time to send a timing frame.
	int64_t timing_frame_delay_ms =
	encoded_image->capture_time_ms_ - last_timing_frame_time_ms_;
	// Trigger threshold if it's a first frame, too long passed since the last
	// timing frame, or we already sent timing frame on a different simulcast
	// stream with the same capture time.
	if (last_timing_frame_time_ms_ == -1 \|\|
	timing_frame_delay_ms >=
	codec_settings_.timing_frame_thresholds.delay_ms \|\|
	timing_frame_delay_ms == 0) {
	timing_flags \|= VideoSendTiming::kTriggeredByTimer;
	last_timing_frame_time_ms_ = encoded_image->capture_time_ms_;
	}

	// Workaround for chromoting encoder: it passes encode start and finished
	// timestamps in \|timing_\| field, but they (together with capture timestamp)
	// are not in the WebRTC clock.
	if (internal_source_ && encoded_image->timing_.encode_finish_ms > 0 &&
	encoded_image->timing_.encode_start_ms > 0) {
	int64_t clock_offset_ms =
	encode_done_ms - encoded_image->timing_.encode_finish_ms;
	// Translate capture timestamp to local WebRTC clock.
	encoded_image->capture_time_ms_ += clock_offset_ms;
	encoded_image->SetTimestamp(
	static_cast<uint32_t>(encoded_image->capture_time_ms_ * 90));
	encode_start_ms.emplace(encoded_image->timing_.encode_start_ms +
	clock_offset_ms);
	}

	// If encode start is not available that means that encoder uses internal
	// source. In that case capture timestamp may be from a different clock with a
	// drift relative to rtc::TimeMillis(). We can't use it for Timing frames,
	// because to being sent in the network capture time required to be less than
	// all the other timestamps.
	if (encode_start_ms) {
	encoded_image->SetEncodeTime(*encode_start_ms, encode_done_ms);
	encoded_image->timing_.flags = timing_flags;
	} else {
	encoded_image->timing_.flags = VideoSendTiming::kInvalid;
	}
	}

	std::unique_ptr<RTPFragmentationHeader>
	FrameEncodeMetadataWriter::UpdateBitstream(
	const CodecSpecificInfo* codec_specific_info,
	const RTPFragmentationHeader* fragmentation,
	EncodedImage* encoded_image) {
	if (!codec_specific_info \|\|
	codec_specific_info->codecType != kVideoCodecH264 \|\| !fragmentation \|\|
	encoded_image->_frameType != VideoFrameType::kVideoFrameKey) {
	return nullptr;
	}

	rtc::Buffer modified_buffer;
	std::unique_ptr<RTPFragmentationHeader> modified_fragmentation =
	absl::make_unique<RTPFragmentationHeader>();
	modified_fragmentation->CopyFrom(*fragmentation);

	// Make sure that the data is not copied if owned by EncodedImage.
	const EncodedImage& buffer = *encoded_image;
	SpsVuiRewriter::ParseOutgoingBitstreamAndRewriteSps(
	buffer, fragmentation->fragmentationVectorSize,
	fragmentation->fragmentationOffset, fragmentation->fragmentationLength,
	encoded_image->ColorSpace(), &modified_buffer,
	modified_fragmentation->fragmentationOffset,
	modified_fragmentation->fragmentationLength);

	encoded_image->SetEncodedData(
	new rtc::RefCountedObject<EncodedImageBufferWrapper>(
	std::move(modified_buffer)));

	return modified_fragmentation;
	}

	void FrameEncodeMetadataWriter::Reset() {
	rtc::CritScope cs(&lock_);
	for (auto& info : timing_frames_info_) {
	info.frames.clear();
	}
	last_timing_frame_time_ms_ = -1;
	reordered_frames_logged_messages_ = 0;
	stalled_encoder_logged_messages_ = 0;
	}

	absl::optional<int64_t>
	FrameEncodeMetadataWriter::ExtractEncodeStartTimeAndFillMetadata(
	size_t simulcast_svc_idx,
	EncodedImage* encoded_image) {
	absl::optional<int64_t> result;
	size_t num_simulcast_svc_streams = timing_frames_info_.size();
	if (simulcast_svc_idx < num_simulcast_svc_streams) {
	auto metadata_list = &timing_frames_info_[simulcast_svc_idx].frames;
	// Skip frames for which there was OnEncodeStarted but no OnEncodedImage
	// call. These are dropped by encoder internally.
	// Because some hardware encoders don't preserve capture timestamp we
	// use RTP timestamps here.
	while (!metadata_list->empty() &&
	IsNewerTimestamp(encoded_image->Timestamp(),
	metadata_list->front().rtp_timestamp)) {
	frame_drop_callback_->OnDroppedFrame(
	EncodedImageCallback::DropReason::kDroppedByEncoder);
	metadata_list->pop_front();
	}

	encoded_image->content_type_ =
	(codec_settings_.mode == VideoCodecMode::kScreensharing)
	? VideoContentType::SCREENSHARE
	: VideoContentType::UNSPECIFIED;

	if (!metadata_list->empty() &&
	metadata_list->front().rtp_timestamp == encoded_image->Timestamp()) {
	result.emplace(metadata_list->front().encode_start_time_ms);
	encoded_image->capture_time_ms_ =
	metadata_list->front().timestamp_us / 1000;
	encoded_image->ntp_time_ms_ = metadata_list->front().ntp_time_ms;
	encoded_image->rotation_ = metadata_list->front().rotation;
	encoded_image->SetColorSpace(metadata_list->front().color_space);
	encoded_image->SetPacketInfos(metadata_list->front().packet_infos);
	metadata_list->pop_front();
	} else {
	++reordered_frames_logged_messages_;
	if (reordered_frames_logged_messages_ <= kMessagesThrottlingThreshold \|\|
	reordered_frames_logged_messages_ % kThrottleRatio == 0) {
	RTC_LOG(LS_WARNING) << "Frame with no encode started time recordings. "
	"Encoder may be reordering frames "
	"or not preserving RTP timestamps.";
	if (reordered_frames_logged_messages_ == kMessagesThrottlingThreshold) {
	RTC_LOG(LS_WARNING) << "Too many log messages. Further frames "
	"reordering warnings will be throttled.";
	}
	}
	}
	}
	return result;
	}

	size_t FrameEncodeMetadataWriter::NumSpatialLayers() const {
	size_t num_spatial_layers = codec_settings_.numberOfSimulcastStreams;
	if (codec_settings_.codecType == kVideoCodecVP9) {
	num_spatial_layers = std::max(
	num_spatial_layers,
	static_cast<size_t>(codec_settings_.VP9().numberOfSpatialLayers));
	}
	return std::max(num_spatial_layers, size_t{1});
	}

	} // namespace webrtc