text: /*
   *  Copyright 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 "video/video_send_stream_impl.h"
  
  #include <stdio.h>
  
  #include <algorithm>
  #include <cstdint>
  #include <string>
  #include <utility>
  
  #include "absl/algorithm/container.h"
  #include "api/crypto/crypto_options.h"
  #include "api/rtp_parameters.h"
  #include "api/scoped_refptr.h"
  #include "api/video_codecs/video_codec.h"
  #include "call/rtp_transport_controller_send_interface.h"
  #include "call/video_send_stream.h"
  #include "modules/pacing/paced_sender.h"
  #include "rtc_base/atomic_ops.h"
  #include "rtc_base/checks.h"
  #include "rtc_base/experiments/alr_experiment.h"
  #include "rtc_base/experiments/field_trial_parser.h"
  #include "rtc_base/experiments/min_video_bitrate_experiment.h"
  #include "rtc_base/experiments/rate_control_settings.h"
  #include "rtc_base/logging.h"
  #include "rtc_base/numerics/safe_conversions.h"
  #include "rtc_base/synchronization/sequence_checker.h"
  #include "rtc_base/thread_checker.h"
  #include "rtc_base/trace_event.h"
  #include "system_wrappers/include/clock.h"
  #include "system_wrappers/include/field_trial.h"
  
  namespace webrtc {
  namespace internal {
  namespace {
  
  // Max positive size difference to treat allocations as "similar".
  static constexpr int kMaxVbaSizeDifferencePercent = 10;
  // Max time we will throttle similar video bitrate allocations.
  static constexpr int64_t kMaxVbaThrottleTimeMs = 500;
  
  constexpr TimeDelta kEncoderTimeOut = TimeDelta::Seconds(2);
  
  bool TransportSeqNumExtensionConfigured(const VideoSendStream::Config& config) {
    const std::vector<RtpExtension>& extensions = config.rtp.extensions;
    return absl::c_any_of(extensions, [](const RtpExtension& ext) {
      return ext.uri == RtpExtension::kTransportSequenceNumberUri;
    });
  }
  
  // Calculate max padding bitrate for a multi layer codec.
  int CalculateMaxPadBitrateBps(const std::vector<VideoStream>& streams,
                                bool is_svc,
                                VideoEncoderConfig::ContentType content_type,
                                int min_transmit_bitrate_bps,
                                bool pad_to_min_bitrate,
                                bool alr_probing) {
    int pad_up_to_bitrate_bps = 0;
  
    RTC_DCHECK(!is_svc || streams.size() <= 1) << "Only one stream is allowed in "
                                                  "SVC mode.";
  
    // Filter out only the active streams;
    std::vector<VideoStream> active_streams;
    for (const VideoStream& stream : streams) {
      if (stream.active)
        active_streams.emplace_back(stream);
    }
  
    if (active_streams.size() > 1 || (!active_streams.empty() && is_svc)) {
      // Simulcast or SVC is used.
      // if SVC is used, stream bitrates should already encode svc bitrates:
      // min_bitrate = min bitrate of a lowest svc layer.
      // target_bitrate = sum of target bitrates of lower layers + min bitrate
      // of the last one (as used in the calculations below).
      // max_bitrate = sum of all active layers' max_bitrate.
      if (alr_probing) {
        // With alr probing, just pad to the min bitrate of the lowest stream,
        // probing will handle the rest of the rampup.
        pad_up_to_bitrate_bps = active_streams[0].min_bitrate_bps;
      } else {
        // Without alr probing, pad up to start bitrate of the
        // highest active stream.
        const double hysteresis_factor =
            RateControlSettings::ParseFromFieldTrials()
                .GetSimulcastHysteresisFactor(content_type);
        if (is_svc) {
          // For SVC, since there is only one "stream", the padding bitrate
          // needed to enable the top spatial layer is stored in the
          // |target_bitrate_bps| field.
          // TODO(sprang): This behavior needs to die.
          pad_up_to_bitrate_bps = static_cast<int>(
              hysteresis_factor * active_streams[0].target_bitrate_bps + 0.5);
        } else {
          const size_t top_active_stream_idx = active_streams.size() - 1;
          pad_up_to_bitrate_bps = std::min(
              static_cast<int>(
                  hysteresis_factor *
                      active_streams[top_active_stream_idx].min_bitrate_bps +
                  0.5),
              active_streams[top_active_stream_idx].target_bitrate_bps);
  
          // Add target_bitrate_bps of the lower active streams.
          for (size_t i = 0; i < top_active_stream_idx; ++i) {
            pad_up_to_bitrate_bps += active_streams[i].target_bitrate_bps;
          }
        }
      }
    } else if (!active_streams.empty() && pad_to_min_bitrate) {
      pad_up_to_bitrate_bps = active_streams[0].min_bitrate_bps;
    }
  
    pad_up_to_bitrate_bps =
        std::max(pad_up_to_bitrate_bps, min_transmit_bitrate_bps);
  
    return pad_up_to_bitrate_bps;
  }
  
  RtpSenderFrameEncryptionConfig CreateFrameEncryptionConfig(
      const VideoSendStream::Config* config) {
    RtpSenderFrameEncryptionConfig frame_encryption_config;
    frame_encryption_config.frame_encryptor = config->frame_encryptor;
    frame_encryption_config.crypto_options = config->crypto_options;
    return frame_encryption_config;
  }
  
  RtpSenderObservers CreateObservers(RtcpRttStats* call_stats,
                                     EncoderRtcpFeedback* encoder_feedback,
                                     SendStatisticsProxy* stats_proxy,
                                     SendDelayStats* send_delay_stats) {
    RtpSenderObservers observers;
    observers.rtcp_rtt_stats = call_stats;
    observers.intra_frame_callback = encoder_feedback;
    observers.rtcp_loss_notification_observer = encoder_feedback;
    observers.rtcp_stats = stats_proxy;
    observers.report_block_data_observer = stats_proxy;
    observers.rtp_stats = stats_proxy;
    observers.bitrate_observer = stats_proxy;
    observers.frame_count_observer = stats_proxy;
    observers.rtcp_type_observer = stats_proxy;
    observers.send_delay_observer = stats_proxy;
    observers.send_packet_observer = send_delay_stats;
    return observers;
  }
  
  absl::optional<AlrExperimentSettings> GetAlrSettings(
      VideoEncoderConfig::ContentType content_type) {
    if (content_type == VideoEncoderConfig::ContentType::kScreen) {
      return AlrExperimentSettings::CreateFromFieldTrial(
          AlrExperimentSettings::kScreenshareProbingBweExperimentName);
    }
    return AlrExperimentSettings::CreateFromFieldTrial(
        AlrExperimentSettings::kStrictPacingAndProbingExperimentName);
  }
  
  bool SameStreamsEnabled(const VideoBitrateAllocation& lhs,
                          const VideoBitrateAllocation& rhs) {
    for (size_t si = 0; si < kMaxSpatialLayers; ++si) {
      for (size_t ti = 0; ti < kMaxTemporalStreams; ++ti) {
        if (lhs.HasBitrate(si, ti) != rhs.HasBitrate(si, ti)) {
          return false;
        }
      }
    }
    return true;
  }
  }  // namespace
  
  PacingConfig::PacingConfig()
      : pacing_factor("factor", PacedSender::kDefaultPaceMultiplier),
        max_pacing_delay("max_delay",
                         TimeDelta::Millis(PacedSender::kMaxQueueLengthMs)) {
    ParseFieldTrial({&pacing_factor, &max_pacing_delay},
                    field_trial::FindFullName("WebRTC-Video-Pacing"));
  }
  PacingConfig::PacingConfig(const PacingConfig&) = default;
  PacingConfig::~PacingConfig() = default;
  
  VideoSendStreamImpl::VideoSendStreamImpl(
      Clock* clock,
      SendStatisticsProxy* stats_proxy,
      rtc::TaskQueue* worker_queue,
      RtcpRttStats* call_stats,
      RtpTransportControllerSendInterface* transport,
      BitrateAllocatorInterface* bitrate_allocator,
      SendDelayStats* send_delay_stats,
      VideoStreamEncoderInterface* video_stream_encoder,
      RtcEventLog* event_log,
      const VideoSendStream::Config* config,
      int initial_encoder_max_bitrate,
      double initial_encoder_bitrate_priority,
      std::map<uint32_t, RtpState> suspended_ssrcs,
      std::map<uint32_t, RtpPayloadState> suspended_payload_states,
      VideoEncoderConfig::ContentType content_type,
      std::unique_ptr<FecController> fec_controller)
      : clock_(clock),
        has_alr_probing_(config->periodic_alr_bandwidth_probing ||
                         GetAlrSettings(content_type)),
        pacing_config_(PacingConfig()),
        stats_proxy_(stats_proxy),
        config_(config),
        worker_queue_(worker_queue),
        timed_out_(false),
        transport_(transport),
        bitrate_allocator_(bitrate_allocator),
        disable_padding_(true),
        max_padding_bitrate_(0),
        encoder_min_bitrate_bps_(0),
        encoder_target_rate_bps_(0),
        encoder_bitrate_priority_(initial_encoder_bitrate_priority),
        has_packet_feedback_(false),
        video_stream_encoder_(video_stream_encoder),
        encoder_feedback_(clock, config_->rtp.ssrcs, video_stream_encoder),
        bandwidth_observer_(transport->GetBandwidthObserver()),
        rtp_video_sender_(
            transport_->CreateRtpVideoSender(suspended_ssrcs,
                                             suspended_payload_states,
                                             config_->rtp,
                                             config_->rtcp_report_interval_ms,
                                             config_->send_transport,
                                             CreateObservers(call_stats,
                                                             &encoder_feedback_,
                                                             stats_proxy_,
                                                             send_delay_stats),
                                             event_log,
                                             std::move(fec_controller),
                                             CreateFrameEncryptionConfig(config_),
                                             config->frame_transformer)),
        weak_ptr_factory_(this) {
    video_stream_encoder->SetFecControllerOverride(rtp_video_sender_);
    RTC_DCHECK_RUN_ON(worker_queue_);
    RTC_LOG(LS_INFO) << "VideoSendStreamInternal: " << config_->ToString();
    weak_ptr_ = weak_ptr_factory_.GetWeakPtr();
  
    encoder_feedback_.SetRtpVideoSender(rtp_video_sender_);
  
    RTC_DCHECK(!config_->rtp.ssrcs.empty());
    RTC_DCHECK(transport_);
    RTC_DCHECK_NE(initial_encoder_max_bitrate, 0);
  
    if (initial_encoder_max_bitrate > 0) {
      encoder_max_bitrate_bps_ =
          rtc::dchecked_cast<uint32_t>(initial_encoder_max_bitrate);
    } else {
      // TODO(srte): Make sure max bitrate is not set to negative values. We don't
      // have any way to handle unset values in downstream code, such as the
      // bitrate allocator. Previously -1 was implicitly casted to UINT32_MAX, a
      // behaviour that is not safe. Converting to 10 Mbps should be safe for
      // reasonable use cases as it allows adding the max of multiple streams
      // without wrappping around.
      const int kFallbackMaxBitrateBps = 10000000;
      RTC_DLOG(LS_ERROR) << "ERROR: Initial encoder max bitrate = "
                         << initial_encoder_max_bitrate << " which is <= 0!";
      RTC_DLOG(LS_INFO) << "Using default encoder max bitrate = 10 Mbps";
      encoder_max_bitrate_bps_ = kFallbackMaxBitrateBps;
    }
  
    RTC_CHECK(AlrExperimentSettings::MaxOneFieldTrialEnabled());
    // If send-side BWE is enabled, check if we should apply updated probing and
    // pacing settings.
    if (TransportSeqNumExtensionConfigured(*config_)) {
      has_packet_feedback_ = true;
  
      absl::optional<AlrExperimentSettings> alr_settings =
          GetAlrSettings(content_type);
      if (alr_settings) {
        transport->EnablePeriodicAlrProbing(true);
        transport->SetPacingFactor(alr_settings->pacing_factor);
        configured_pacing_factor_ = alr_settings->pacing_factor;
        transport->SetQueueTimeLimit(alr_settings->max_paced_queue_time);
      } else {
        RateControlSettings rate_control_settings =
            RateControlSettings::ParseFromFieldTrials();
  
        transport->EnablePeriodicAlrProbing(
            rate_control_settings.UseAlrProbing());
        const double pacing_factor =
            rate_control_settings.GetPacingFactor().value_or(
                pacing_config_.pacing_factor);
        transport->SetPacingFactor(pacing_factor);
        configured_pacing_factor_ = pacing_factor;
        transport->SetQueueTimeLimit(pacing_config_.max_pacing_delay.Get().ms());
      }
    }
  
    if (config_->periodic_alr_bandwidth_probing) {
      transport->EnablePeriodicAlrProbing(true);
    }
  
    RTC_DCHECK_GE(config_->rtp.payload_type, 0);
    RTC_DCHECK_LE(config_->rtp.payload_type, 127);
  
    video_stream_encoder_->SetStartBitrate(
        bitrate_allocator_->GetStartBitrate(this));
  }
  
  VideoSendStreamImpl::~VideoSendStreamImpl() {
    RTC_DCHECK_RUN_ON(worker_queue_);
    RTC_DCHECK(!rtp_video_sender_->IsActive())
        << "VideoSendStreamImpl::Stop not called";
    RTC_LOG(LS_INFO) << "~VideoSendStreamInternal: " << config_->ToString();
    transport_->DestroyRtpVideoSender(rtp_video_sender_);
  }
  
  void VideoSendStreamImpl::RegisterProcessThread(
      ProcessThread* module_process_thread) {
    // Called on libjingle's worker thread (not worker_queue_), as part of the
    // initialization steps. That's also the correct thread/queue for setting the
    // state for |video_stream_encoder_|.
  
    // Only request rotation at the source when we positively know that the remote
    // side doesn't support the rotation extension. This allows us to prepare the
    // encoder in the expectation that rotation is supported - which is the common
    // case.
    bool rotation_applied = absl::c_none_of(
        config_->rtp.extensions, [](const RtpExtension& extension) {
          return extension.uri == RtpExtension::kVideoRotationUri;
        });
  
    video_stream_encoder_->SetSink(this, rotation_applied);
  
    rtp_video_sender_->RegisterProcessThread(module_process_thread);
  }
  
  void VideoSendStreamImpl::DeRegisterProcessThread() {
    rtp_video_sender_->DeRegisterProcessThread();
  }
  
  void VideoSendStreamImpl::DeliverRtcp(const uint8_t* packet, size_t length) {
    // Runs on a network thread.
    RTC_DCHECK(!worker_queue_->IsCurrent());
    rtp_video_sender_->DeliverRtcp(packet, length);
  }
  
  void VideoSendStreamImpl::UpdateActiveSimulcastLayers(
      const std::vector<bool> active_layers) {
    RTC_DCHECK_RUN_ON(worker_queue_);
    bool previously_active = rtp_video_sender_->IsActive();
    rtp_video_sender_->SetActiveModules(active_layers);
    if (!rtp_video_sender_->IsActive() && previously_active) {
      // Payload router switched from active to inactive.
      StopVideoSendStream();
    } else if (rtp_video_sender_->IsActive() && !previously_active) {
      // Payload router switched from inactive to active.
      StartupVideoSendStream();
    }
  }
  
  void VideoSendStreamImpl::Start() {
    RTC_DCHECK_RUN_ON(worker_queue_);
    RTC_LOG(LS_INFO) << "VideoSendStream::Start";
    if (rtp_video_sender_->IsActive())
      return;
    TRACE_EVENT_INSTANT0("webrtc", "VideoSendStream::Start");
    rtp_video_sender_->SetActive(true);
    StartupVideoSendStream();
  }
  
  void VideoSendStreamImpl::StartupVideoSendStream() {
    RTC_DCHECK_RUN_ON(worker_queue_);
    bitrate_allocator_->AddObserver(this, GetAllocationConfig());
    // Start monitoring encoder activity.
    {
      RTC_DCHECK(!check_encoder_activity_task_.Running());
  
      activity_ = false;
      timed_out_ = false;
      check_encoder_activity_task_ = RepeatingTaskHandle::DelayedStart(
          worker_queue_->Get(), kEncoderTimeOut, [this] {
            RTC_DCHECK_RUN_ON(worker_queue_);
            if (!activity_) {
              if (!timed_out_) {
                SignalEncoderTimedOut();
              }
              timed_out_ = true;
              disable_padding_ = true;
            } else if (timed_out_) {
              SignalEncoderActive();
              timed_out_ = false;
            }
            activity_ = false;
            return kEncoderTimeOut;
          });
    }
  
    video_stream_encoder_->SendKeyFrame();
  }
  
  void VideoSendStreamImpl::Stop() {
    RTC_DCHECK_RUN_ON(worker_queue_);
    RTC_LOG(LS_INFO) << "VideoSendStream::Stop";
    if (!rtp_video_sender_->IsActive())
      return;
    TRACE_EVENT_INSTANT0("webrtc", "VideoSendStream::Stop");
    rtp_video_sender_->SetActive(false);
    StopVideoSendStream();
  }
  
  void VideoSendStreamImpl::StopVideoSendStream() {
    bitrate_allocator_->RemoveObserver(this);
    check_encoder_activity_task_.Stop();
    video_stream_encoder_->OnBitrateUpdated(DataRate::Zero(), DataRate::Zero(),
                                            DataRate::Zero(), 0, 0, 0);
    stats_proxy_->OnSetEncoderTargetRate(0);
  }
  
  void VideoSendStreamImpl::SignalEncoderTimedOut() {
    RTC_DCHECK_RUN_ON(worker_queue_);
    // If the encoder has not produced anything the last kEncoderTimeOut and it
    // is supposed to, deregister as BitrateAllocatorObserver. This can happen
    // if a camera stops producing frames.
    if (encoder_target_rate_bps_ > 0) {
      RTC_LOG(LS_INFO) << "SignalEncoderTimedOut, Encoder timed out.";
      bitrate_allocator_->RemoveObserver(this);
    }
  }
  
  void VideoSendStreamImpl::OnBitrateAllocationUpdated(
      const VideoBitrateAllocation& allocation) {
    if (!worker_queue_->IsCurrent()) {
      auto ptr = weak_ptr_;
      worker_queue_->PostTask([=] {
        if (!ptr.get())
          return;
        ptr->OnBitrateAllocationUpdated(allocation);
      });
      return;
    }
  
    RTC_DCHECK_RUN_ON(worker_queue_);
  
    int64_t now_ms = clock_->TimeInMilliseconds();
    if (encoder_target_rate_bps_ != 0) {
      if (video_bitrate_allocation_context_) {
        // If new allocation is within kMaxVbaSizeDifferencePercent larger than
        // the previously sent allocation and the same streams are still enabled,
        // it is considered "similar". We do not want send similar allocations
        // more once per kMaxVbaThrottleTimeMs.
        const VideoBitrateAllocation& last =
            video_bitrate_allocation_context_->last_sent_allocation;
        const bool is_similar =
            allocation.get_sum_bps() >= last.get_sum_bps() &&
            allocation.get_sum_bps() <
                (last.get_sum_bps() * (100 + kMaxVbaSizeDifferencePercent)) /
                    100 &&
            SameStreamsEnabled(allocation, last);
        if (is_similar &&
            (now_ms - video_bitrate_allocation_context_->last_send_time_ms) <
                kMaxVbaThrottleTimeMs) {
          // This allocation is too similar, cache it and return.
          video_bitrate_allocation_context_->throttled_allocation = allocation;
          return;
        }
      } else {
        video_bitrate_allocation_context_.emplace();
      }
  
      video_bitrate_allocation_context_->last_sent_allocation = allocation;
      video_bitrate_allocation_context_->throttled_allocation.reset();
      video_bitrate_allocation_context_->last_send_time_ms = now_ms;
  
      // Send bitrate allocation metadata only if encoder is not paused.
      rtp_video_sender_->OnBitrateAllocationUpdated(allocation);
    }
  }
  
  void VideoSendStreamImpl::SignalEncoderActive() {
    RTC_DCHECK_RUN_ON(worker_queue_);
    if (rtp_video_sender_->IsActive()) {
      RTC_LOG(LS_INFO) << "SignalEncoderActive, Encoder is active.";
      bitrate_allocator_->AddObserver(this, GetAllocationConfig());
    }
  }
  
  MediaStreamAllocationConfig VideoSendStreamImpl::GetAllocationConfig() const {
    return MediaStreamAllocationConfig{
        static_cast<uint32_t>(encoder_min_bitrate_bps_),
        encoder_max_bitrate_bps_,
        static_cast<uint32_t>(disable_padding_ ? 0 : max_padding_bitrate_),
        /* priority_bitrate */ 0,
        !config_->suspend_below_min_bitrate,
        encoder_bitrate_priority_};
  }
  
  void VideoSendStreamImpl::OnEncoderConfigurationChanged(
      std::vector<VideoStream> streams,
      bool is_svc,
      VideoEncoderConfig::ContentType content_type,
      int min_transmit_bitrate_bps) {
    if (!worker_queue_->IsCurrent()) {
      rtc::WeakPtr<VideoSendStreamImpl> send_stream = weak_ptr_;
      worker_queue_->PostTask([send_stream, streams, is_svc, content_type,
                               min_transmit_bitrate_bps]() mutable {
        if (send_stream) {
          send_stream->OnEncoderConfigurationChanged(
              std::move(streams), is_svc, content_type, min_transmit_bitrate_bps);
        }
      });
      return;
    }
  
    RTC_DCHECK_GE(config_->rtp.ssrcs.size(), streams.size());
    TRACE_EVENT0("webrtc", "VideoSendStream::OnEncoderConfigurationChanged");
    RTC_DCHECK_RUN_ON(worker_queue_);
  
    const VideoCodecType codec_type =
        PayloadStringToCodecType(config_->rtp.payload_name);
  
    const absl::optional<DataRate> experimental_min_bitrate =
        GetExperimentalMinVideoBitrate(codec_type);
    encoder_min_bitrate_bps_ =
        experimental_min_bitrate
            ? experimental_min_bitrate->bps()
            : std::max(streams[0].min_bitrate_bps, kDefaultMinVideoBitrateBps);
  
    encoder_max_bitrate_bps_ = 0;
    double stream_bitrate_priority_sum = 0;
    for (const auto& stream : streams) {
      // We don't want to allocate more bitrate than needed to inactive streams.
      encoder_max_bitrate_bps_ += stream.active ? stream.max_bitrate_bps : 0;
      if (stream.bitrate_priority) {
        RTC_DCHECK_GT(*stream.bitrate_priority, 0);
        stream_bitrate_priority_sum += *stream.bitrate_priority;
      }
    }
    RTC_DCHECK_GT(stream_bitrate_priority_sum, 0);
    encoder_bitrate_priority_ = stream_bitrate_priority_sum;
    encoder_max_bitrate_bps_ =
        std::max(static_cast<uint32_t>(encoder_min_bitrate_bps_),
                 encoder_max_bitrate_bps_);
  
    // TODO(bugs.webrtc.org/10266): Query the VideoBitrateAllocator instead.
    max_padding_bitrate_ = CalculateMaxPadBitrateBps(
        streams, is_svc, content_type, min_transmit_bitrate_bps,
        config_->suspend_below_min_bitrate, has_alr_probing_);
  
    // Clear stats for disabled layers.
    for (size_t i = streams.size(); i < config_->rtp.ssrcs.size(); ++i) {
      stats_proxy_->OnInactiveSsrc(config_->rtp.ssrcs[i]);
    }
  
    const size_t num_temporal_layers =
        streams.back().num_temporal_layers.value_or(1);
  
    rtp_video_sender_->SetEncodingData(streams[0].width, streams[0].height,
                                       num_temporal_layers);
  
    if (rtp_video_sender_->IsActive()) {
      // The send stream is started already. Update the allocator with new bitrate
      // limits.
      bitrate_allocator_->AddObserver(this, GetAllocationConfig());
    }
  }
  
  EncodedImageCallback::Result VideoSendStreamImpl::OnEncodedImage(
      const EncodedImage& encoded_image,
      const CodecSpecificInfo* codec_specific_info) {
    // 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.
  
    // Indicate that there still is activity going on.
    activity_ = true;
  
    auto enable_padding_task = [this]() {
      if (disable_padding_) {
        RTC_DCHECK_RUN_ON(worker_queue_);
        disable_padding_ = false;
        // To ensure that padding bitrate is propagated to the bitrate allocator.
        SignalEncoderActive();
      }
    };
    if (!worker_queue_->IsCurrent()) {
      worker_queue_->PostTask(enable_padding_task);
    } else {
      enable_padding_task();
    }
  
    EncodedImageCallback::Result result(EncodedImageCallback::Result::OK);
    result =
        rtp_video_sender_->OnEncodedImage(encoded_image, codec_specific_info);
    // Check if there's a throttled VideoBitrateAllocation that we should try
    // sending.
    rtc::WeakPtr<VideoSendStreamImpl> send_stream = weak_ptr_;
    auto update_task = [send_stream]() {
      if (send_stream) {
        RTC_DCHECK_RUN_ON(send_stream->worker_queue_);
        auto& context = send_stream->video_bitrate_allocation_context_;
        if (context && context->throttled_allocation) {
          send_stream->OnBitrateAllocationUpdated(*context->throttled_allocation);
        }
      }
    };
    if (!worker_queue_->IsCurrent()) {
      worker_queue_->PostTask(update_task);
    } else {
      update_task();
    }
  
    return result;
  }
  
  void VideoSendStreamImpl::OnDroppedFrame(
      EncodedImageCallback::DropReason reason) {
    activity_ = true;
  }
  
  std::map<uint32_t, RtpState> VideoSendStreamImpl::GetRtpStates() const {
    return rtp_video_sender_->GetRtpStates();
  }
  
  std::map<uint32_t, RtpPayloadState> VideoSendStreamImpl::GetRtpPayloadStates()
      const {
    return rtp_video_sender_->GetRtpPayloadStates();
  }
  
  uint32_t VideoSendStreamImpl::OnBitrateUpdated(BitrateAllocationUpdate update) {
    RTC_DCHECK_RUN_ON(worker_queue_);
    RTC_DCHECK(rtp_video_sender_->IsActive())
        << "VideoSendStream::Start has not been called.";
  
    // When the BWE algorithm doesn't pass a stable estimate, we'll use the
    // unstable one instead.
    if (update.stable_target_bitrate.IsZero()) {
      update.stable_target_bitrate = update.target_bitrate;
    }
  
    rtp_video_sender_->OnBitrateUpdated(update, stats_proxy_->GetSendFrameRate());
    encoder_target_rate_bps_ = rtp_video_sender_->GetPayloadBitrateBps();
    const uint32_t protection_bitrate_bps =
        rtp_video_sender_->GetProtectionBitrateBps();
    DataRate link_allocation = DataRate::Zero();
    if (encoder_target_rate_bps_ > protection_bitrate_bps) {
      link_allocation =
          DataRate::BitsPerSec(encoder_target_rate_bps_ - protection_bitrate_bps);
    }
    DataRate overhead =
        update.target_bitrate - DataRate::BitsPerSec(encoder_target_rate_bps_);
    DataRate encoder_stable_target_rate = update.stable_target_bitrate;
    if (encoder_stable_target_rate > overhead) {
      encoder_stable_target_rate = encoder_stable_target_rate - overhead;
    } else {
      encoder_stable_target_rate = DataRate::BitsPerSec(encoder_target_rate_bps_);
    }
  
    encoder_target_rate_bps_ =
        std::min(encoder_max_bitrate_bps_, encoder_target_rate_bps_);
  
    encoder_stable_target_rate =
        std::min(DataRate::BitsPerSec(encoder_max_bitrate_bps_),
                 encoder_stable_target_rate);
  
    DataRate encoder_target_rate = DataRate::BitsPerSec(encoder_target_rate_bps_);
    link_allocation = std::max(encoder_target_rate, link_allocation);
    video_stream_encoder_->OnBitrateUpdated(
        encoder_target_rate, encoder_stable_target_rate, link_allocation,
        rtc::dchecked_cast<uint8_t>(update.packet_loss_ratio * 256),
        update.round_trip_time.ms(), update.cwnd_reduce_ratio);
    stats_proxy_->OnSetEncoderTargetRate(encoder_target_rate_bps_);
    return protection_bitrate_bps;
  }
  
  }  // namespace internal
  }  // namespace webrtc
  