modules/congestion_controller/rtp/transport_feedback_adapter.cc - src - Git at Google

 /*
  *  Copyright (c) 2015 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 "modules/congestion_controller/rtp/transport_feedback_adapter.h"

 #include <stdlib.h>

 #include <algorithm>
 #include <cmath>
 #include <utility>

 #include "absl/algorithm/container.h"
 #include "api/units/timestamp.h"
 #include "modules/rtp_rtcp/include/rtp_rtcp_defines.h"
 #include "modules/rtp_rtcp/source/rtcp_packet/transport_feedback.h"
 #include "rtc_base/checks.h"
 #include "rtc_base/logging.h"
 #include "system_wrappers/include/field_trial.h"

 namespace webrtc {

 constexpr TimeDelta kSendTimeHistoryWindow = TimeDelta::Seconds<60>();

 void InFlightBytesTracker::AddInFlightPacketBytes(
     const PacketFeedback& packet) {
   RTC_DCHECK(packet.sent.send_time.IsFinite());
   auto it = in_flight_data_.find({packet.local_net_id, packet.remote_net_id});
   if (it != in_flight_data_.end()) {
     it->second += packet.sent.size;
   } else {
     in_flight_data_.insert(
         {{packet.local_net_id, packet.remote_net_id}, packet.sent.size});
   }
 }

 void InFlightBytesTracker::RemoveInFlightPacketBytes(
     const PacketFeedback& packet) {
   if (packet.sent.send_time.IsInfinite())
     return;
   auto it = in_flight_data_.find({packet.local_net_id, packet.remote_net_id});
   if (it != in_flight_data_.end()) {
     RTC_DCHECK_GE(it->second, packet.sent.size);
     it->second -= packet.sent.size;
     if (it->second.IsZero())
       in_flight_data_.erase(it);
   }
 }

 DataSize InFlightBytesTracker::GetOutstandingData(
     uint16_t local_net_id,
     uint16_t remote_net_id) const {
   auto it = in_flight_data_.find({local_net_id, remote_net_id});
   if (it != in_flight_data_.end()) {
     return it->second;
   } else {
     return DataSize::Zero();
   }
 }

 TransportFeedbackAdapter::TransportFeedbackAdapter() = default;

 TransportFeedbackAdapter::~TransportFeedbackAdapter() {
   RTC_DCHECK(observers_.empty());
 }

 void TransportFeedbackAdapter::RegisterStreamFeedbackObserver(
     std::vector<uint32_t> ssrcs,
     StreamFeedbackObserver* observer) {
   rtc::CritScope cs(&observers_lock_);
   RTC_DCHECK(observer);
   RTC_DCHECK(absl::c_find_if(observers_, [=](const auto& pair) {
                return pair.second == observer;
              }) == observers_.end());
   observers_.push_back({ssrcs, observer});
 }

 void TransportFeedbackAdapter::DeRegisterStreamFeedbackObserver(
     StreamFeedbackObserver* observer) {
   rtc::CritScope cs(&observers_lock_);
   RTC_DCHECK(observer);
   const auto it = absl::c_find_if(
       observers_, [=](const auto& pair) { return pair.second == observer; });
   RTC_DCHECK(it != observers_.end());
   observers_.erase(it);
 }

 void TransportFeedbackAdapter::AddPacket(const RtpPacketSendInfo& packet_info,
                                          size_t overhead_bytes,
                                          Timestamp creation_time) {
   {
     rtc::CritScope cs(&lock_);
     PacketFeedback packet;
     packet.creation_time = creation_time;
     packet.sent.sequence_number =
         seq_num_unwrapper_.Unwrap(packet_info.transport_sequence_number);
     packet.sent.size = DataSize::bytes(packet_info.length + overhead_bytes);
     packet.local_net_id = local_net_id_;
     packet.remote_net_id = remote_net_id_;
     packet.sent.pacing_info = packet_info.pacing_info;
     if (packet_info.has_rtp_sequence_number) {
       packet.ssrc = packet_info.ssrc;
       packet.rtp_sequence_number = packet_info.rtp_sequence_number;
     }

     while (!history_.empty() &&
            creation_time - history_.begin()->second.creation_time >
                kSendTimeHistoryWindow) {
       // TODO(sprang): Warn if erasing (too many) old items?
       if (history_.begin()->second.sent.sequence_number > last_ack_seq_num_)
         in_flight_.RemoveInFlightPacketBytes(history_.begin()->second);
       history_.erase(history_.begin());
     }
     history_.insert(std::make_pair(packet.sent.sequence_number, packet));
   }
 }
 absl::optional<SentPacket> TransportFeedbackAdapter::ProcessSentPacket(
     const rtc::SentPacket& sent_packet) {
   rtc::CritScope cs(&lock_);
   auto send_time = Timestamp::ms(sent_packet.send_time_ms);
   // TODO(srte): Only use one way to indicate that packet feedback is used.
   if (sent_packet.info.included_in_feedback || sent_packet.packet_id != -1) {
     int64_t unwrapped_seq_num =
         seq_num_unwrapper_.Unwrap(sent_packet.packet_id);
     auto it = history_.find(unwrapped_seq_num);
     if (it != history_.end()) {
       bool packet_retransmit = it->second.sent.send_time.IsFinite();
       it->second.sent.send_time = send_time;
       last_send_time_ = std::max(last_send_time_, send_time);
       // TODO(srte): Don't do this on retransmit.
       if (!pending_untracked_size_.IsZero()) {
         if (send_time < last_untracked_send_time_)
           RTC_LOG(LS_WARNING)
               << "appending acknowledged data for out of order packet. (Diff: "
               << ToString(last_untracked_send_time_ - send_time) << " ms.)";
         it->second.sent.prior_unacked_data += pending_untracked_size_;
         pending_untracked_size_ = DataSize::Zero();
       }
       if (!packet_retransmit) {
         if (it->second.sent.sequence_number > last_ack_seq_num_)
           in_flight_.AddInFlightPacketBytes(it->second);
         it->second.sent.data_in_flight = GetOutstandingData();
         return it->second.sent;
       }
     }
   } else if (sent_packet.info.included_in_allocation) {
     if (send_time < last_send_time_) {
       RTC_LOG(LS_WARNING) << "ignoring untracked data for out of order packet.";
     }
     pending_untracked_size_ +=
         DataSize::bytes(sent_packet.info.packet_size_bytes);
     last_untracked_send_time_ = std::max(last_untracked_send_time_, send_time);
   }
   return absl::nullopt;
 }

 absl::optional<TransportPacketsFeedback>
 TransportFeedbackAdapter::ProcessTransportFeedback(
     const rtcp::TransportFeedback& feedback,
     Timestamp feedback_receive_time) {
   if (feedback.GetPacketStatusCount() == 0) {
     RTC_LOG(LS_INFO) << "Empty transport feedback packet received.";
     return absl::nullopt;
   }
   std::vector<PacketFeedback> feedback_vector;
   TransportPacketsFeedback msg;
   msg.feedback_time = feedback_receive_time;
   {
     rtc::CritScope cs(&lock_);
     msg.prior_in_flight =
         in_flight_.GetOutstandingData(local_net_id_, remote_net_id_);
     feedback_vector =
         ProcessTransportFeedbackInner(feedback, feedback_receive_time);
     if (feedback_vector.empty())
       return absl::nullopt;

     for (const PacketFeedback& fb : feedback_vector) {
       PacketResult res;
       res.sent_packet = fb.sent;
       res.receive_time = fb.receive_time;
       msg.packet_feedbacks.push_back(res);
     }
     auto it = history_.find(last_ack_seq_num_);
     if (it != history_.end()) {
       msg.first_unacked_send_time = it->second.sent.send_time;
     }
     msg.data_in_flight =
         in_flight_.GetOutstandingData(local_net_id_, remote_net_id_);
   }
   SignalObservers(feedback_vector);
   return msg;
 }

 void TransportFeedbackAdapter::SetNetworkIds(uint16_t local_id,
                                              uint16_t remote_id) {
   rtc::CritScope cs(&lock_);
   local_net_id_ = local_id;
   remote_net_id_ = remote_id;
 }

 DataSize TransportFeedbackAdapter::GetOutstandingData() const {
   rtc::CritScope cs(&lock_);
   return in_flight_.GetOutstandingData(local_net_id_, remote_net_id_);
 }

 std::vector<PacketFeedback>
 TransportFeedbackAdapter::ProcessTransportFeedbackInner(
     const rtcp::TransportFeedback& feedback,
     Timestamp feedback_time) {
   // Add timestamp deltas to a local time base selected on first packet arrival.
   // This won't be the true time base, but makes it easier to manually inspect
   // time stamps.
   if (last_timestamp_.IsInfinite()) {
     current_offset_ = feedback_time;
   } else {
     // TODO(srte): We shouldn't need to do rounding here.
     const TimeDelta delta = feedback.GetBaseDelta(last_timestamp_)
                                 .RoundDownTo(TimeDelta::Millis<1>());
     // Protect against assigning current_offset_ negative value.
     if (delta < Timestamp::Zero() - current_offset_) {
       RTC_LOG(LS_WARNING) << "Unexpected feedback timestamp received.";
       current_offset_ = feedback_time;
     } else {
       current_offset_ += delta;
     }
   }
   last_timestamp_ = feedback.GetBaseTime();

   std::vector<PacketFeedback> packet_feedback_vector;
   packet_feedback_vector.reserve(feedback.GetPacketStatusCount());

   size_t failed_lookups = 0;
   size_t ignored = 0;
   TimeDelta packet_offset = TimeDelta::Zero();
   for (const auto& packet : feedback.GetAllPackets()) {
     int64_t seq_num = seq_num_unwrapper_.Unwrap(packet.sequence_number());

     if (seq_num > last_ack_seq_num_) {
       // Starts at history_.begin() if last_ack_seq_num_ < 0, since any valid
       // sequence number is >= 0.
       for (auto it = history_.upper_bound(last_ack_seq_num_);
            it != history_.upper_bound(seq_num); ++it) {
         in_flight_.RemoveInFlightPacketBytes(it->second);
       }
       last_ack_seq_num_ = seq_num;
     }

     auto it = history_.find(seq_num);
     if (it == history_.end()) {
       ++failed_lookups;
       continue;
     }

     if (it->second.sent.send_time.IsInfinite()) {
       // TODO(srte): Fix the tests that makes this happen and make this a
       // DCHECK.
       RTC_DLOG(LS_ERROR)
           << "Received feedback before packet was indicated as sent";
       continue;
     }

     PacketFeedback packet_feedback = it->second;
     if (packet.received()) {
       packet_offset += packet.delta();
       packet_feedback.receive_time =
           current_offset_ + packet_offset.RoundDownTo(TimeDelta::Millis<1>());
       // Note: Lost packets are not removed from history because they might be
       // reported as received by a later feedback.
       history_.erase(it);
     }
     if (packet_feedback.local_net_id == local_net_id_ &&
         packet_feedback.remote_net_id == remote_net_id_) {
       packet_feedback_vector.push_back(packet_feedback);
     } else {
       ++ignored;
     }
   }

   if (failed_lookups > 0) {
     RTC_LOG(LS_WARNING) << "Failed to lookup send time for " << failed_lookups
                         << " packet" << (failed_lookups > 1 ? "s" : "")
                         << ". Send time history too small?";
   }
   if (ignored > 0) {
     RTC_LOG(LS_INFO) << "Ignoring " << ignored
                      << " packets because they were sent on a different route.";
   }

   return packet_feedback_vector;
 }

 void TransportFeedbackAdapter::SignalObservers(
     const std::vector<PacketFeedback>& feedback_vector) {
   rtc::CritScope cs(&observers_lock_);
   for (auto& observer : observers_) {
     std::vector<StreamFeedbackObserver::StreamPacketInfo> selected_feedback;
     for (const auto& packet : feedback_vector) {
       if (packet.ssrc && absl::c_count(observer.first, *packet.ssrc) > 0) {
         StreamFeedbackObserver::StreamPacketInfo packet_info;
         packet_info.ssrc = *packet.ssrc;
         packet_info.rtp_sequence_number = packet.rtp_sequence_number;
         packet_info.received = packet.receive_time.IsFinite();
         selected_feedback.push_back(packet_info);
       }
     }
     if (!selected_feedback.empty()) {
       observer.second->OnPacketFeedbackVector(std::move(selected_feedback));
     }
   }
 }

 }  // namespace webrtc
	/*
	* Copyright (c) 2015 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 "modules/congestion_controller/rtp/transport_feedback_adapter.h"

	#include <stdlib.h>

	#include <algorithm>
	#include <cmath>
	#include <utility>

	#include "absl/algorithm/container.h"
	#include "api/units/timestamp.h"
	#include "modules/rtp_rtcp/include/rtp_rtcp_defines.h"
	#include "modules/rtp_rtcp/source/rtcp_packet/transport_feedback.h"
	#include "rtc_base/checks.h"
	#include "rtc_base/logging.h"
	#include "system_wrappers/include/field_trial.h"

	namespace webrtc {

	constexpr TimeDelta kSendTimeHistoryWindow = TimeDelta::Seconds<60>();

	void InFlightBytesTracker::AddInFlightPacketBytes(
	const PacketFeedback& packet) {
	RTC_DCHECK(packet.sent.send_time.IsFinite());
	auto it = in_flight_data_.find({packet.local_net_id, packet.remote_net_id});
	if (it != in_flight_data_.end()) {
	it->second += packet.sent.size;
	} else {
	in_flight_data_.insert(
	{{packet.local_net_id, packet.remote_net_id}, packet.sent.size});
	}
	}

	void InFlightBytesTracker::RemoveInFlightPacketBytes(
	const PacketFeedback& packet) {
	if (packet.sent.send_time.IsInfinite())
	return;
	auto it = in_flight_data_.find({packet.local_net_id, packet.remote_net_id});
	if (it != in_flight_data_.end()) {
	RTC_DCHECK_GE(it->second, packet.sent.size);
	it->second -= packet.sent.size;
	if (it->second.IsZero())
	in_flight_data_.erase(it);
	}
	}

	DataSize InFlightBytesTracker::GetOutstandingData(
	uint16_t local_net_id,
	uint16_t remote_net_id) const {
	auto it = in_flight_data_.find({local_net_id, remote_net_id});
	if (it != in_flight_data_.end()) {
	return it->second;
	} else {
	return DataSize::Zero();
	}
	}

	TransportFeedbackAdapter::TransportFeedbackAdapter() = default;

	TransportFeedbackAdapter::~TransportFeedbackAdapter() {
	RTC_DCHECK(observers_.empty());
	}

	void TransportFeedbackAdapter::RegisterStreamFeedbackObserver(
	std::vector<uint32_t> ssrcs,
	StreamFeedbackObserver* observer) {
	rtc::CritScope cs(&observers_lock_);
	RTC_DCHECK(observer);
	RTC_DCHECK(absl::c_find_if(observers_, [=](const auto& pair) {
	return pair.second == observer;
	}) == observers_.end());
	observers_.push_back({ssrcs, observer});
	}

	void TransportFeedbackAdapter::DeRegisterStreamFeedbackObserver(
	StreamFeedbackObserver* observer) {
	rtc::CritScope cs(&observers_lock_);
	RTC_DCHECK(observer);
	const auto it = absl::c_find_if(
	observers_, [=](const auto& pair) { return pair.second == observer; });
	RTC_DCHECK(it != observers_.end());
	observers_.erase(it);
	}

	void TransportFeedbackAdapter::AddPacket(const RtpPacketSendInfo& packet_info,
	size_t overhead_bytes,
	Timestamp creation_time) {
	{
	rtc::CritScope cs(&lock_);
	PacketFeedback packet;
	packet.creation_time = creation_time;
	packet.sent.sequence_number =
	seq_num_unwrapper_.Unwrap(packet_info.transport_sequence_number);
	packet.sent.size = DataSize::bytes(packet_info.length + overhead_bytes);
	packet.local_net_id = local_net_id_;
	packet.remote_net_id = remote_net_id_;
	packet.sent.pacing_info = packet_info.pacing_info;
	if (packet_info.has_rtp_sequence_number) {
	packet.ssrc = packet_info.ssrc;
	packet.rtp_sequence_number = packet_info.rtp_sequence_number;
	}

	while (!history_.empty() &&
	creation_time - history_.begin()->second.creation_time >
	kSendTimeHistoryWindow) {
	// TODO(sprang): Warn if erasing (too many) old items?
	if (history_.begin()->second.sent.sequence_number > last_ack_seq_num_)
	in_flight_.RemoveInFlightPacketBytes(history_.begin()->second);
	history_.erase(history_.begin());
	}
	history_.insert(std::make_pair(packet.sent.sequence_number, packet));
	}
	}
	absl::optional<SentPacket> TransportFeedbackAdapter::ProcessSentPacket(
	const rtc::SentPacket& sent_packet) {
	rtc::CritScope cs(&lock_);
	auto send_time = Timestamp::ms(sent_packet.send_time_ms);
	// TODO(srte): Only use one way to indicate that packet feedback is used.
	if (sent_packet.info.included_in_feedback \|\| sent_packet.packet_id != -1) {
	int64_t unwrapped_seq_num =
	seq_num_unwrapper_.Unwrap(sent_packet.packet_id);
	auto it = history_.find(unwrapped_seq_num);
	if (it != history_.end()) {
	bool packet_retransmit = it->second.sent.send_time.IsFinite();
	it->second.sent.send_time = send_time;
	last_send_time_ = std::max(last_send_time_, send_time);
	// TODO(srte): Don't do this on retransmit.
	if (!pending_untracked_size_.IsZero()) {
	if (send_time < last_untracked_send_time_)
	RTC_LOG(LS_WARNING)
	<< "appending acknowledged data for out of order packet. (Diff: "
	<< ToString(last_untracked_send_time_ - send_time) << " ms.)";
	it->second.sent.prior_unacked_data += pending_untracked_size_;
	pending_untracked_size_ = DataSize::Zero();
	}
	if (!packet_retransmit) {
	if (it->second.sent.sequence_number > last_ack_seq_num_)
	in_flight_.AddInFlightPacketBytes(it->second);
	it->second.sent.data_in_flight = GetOutstandingData();
	return it->second.sent;
	}
	}
	} else if (sent_packet.info.included_in_allocation) {
	if (send_time < last_send_time_) {
	RTC_LOG(LS_WARNING) << "ignoring untracked data for out of order packet.";
	}
	pending_untracked_size_ +=
	DataSize::bytes(sent_packet.info.packet_size_bytes);
	last_untracked_send_time_ = std::max(last_untracked_send_time_, send_time);
	}
	return absl::nullopt;
	}

	absl::optional<TransportPacketsFeedback>
	TransportFeedbackAdapter::ProcessTransportFeedback(
	const rtcp::TransportFeedback& feedback,
	Timestamp feedback_receive_time) {
	if (feedback.GetPacketStatusCount() == 0) {
	RTC_LOG(LS_INFO) << "Empty transport feedback packet received.";
	return absl::nullopt;
	}
	std::vector<PacketFeedback> feedback_vector;
	TransportPacketsFeedback msg;
	msg.feedback_time = feedback_receive_time;
	{
	rtc::CritScope cs(&lock_);
	msg.prior_in_flight =
	in_flight_.GetOutstandingData(local_net_id_, remote_net_id_);
	feedback_vector =
	ProcessTransportFeedbackInner(feedback, feedback_receive_time);
	if (feedback_vector.empty())
	return absl::nullopt;

	for (const PacketFeedback& fb : feedback_vector) {
	PacketResult res;
	res.sent_packet = fb.sent;
	res.receive_time = fb.receive_time;
	msg.packet_feedbacks.push_back(res);
	}
	auto it = history_.find(last_ack_seq_num_);
	if (it != history_.end()) {
	msg.first_unacked_send_time = it->second.sent.send_time;
	}
	msg.data_in_flight =
	in_flight_.GetOutstandingData(local_net_id_, remote_net_id_);
	}
	SignalObservers(feedback_vector);
	return msg;
	}

	void TransportFeedbackAdapter::SetNetworkIds(uint16_t local_id,
	uint16_t remote_id) {
	rtc::CritScope cs(&lock_);
	local_net_id_ = local_id;
	remote_net_id_ = remote_id;
	}

	DataSize TransportFeedbackAdapter::GetOutstandingData() const {
	rtc::CritScope cs(&lock_);
	return in_flight_.GetOutstandingData(local_net_id_, remote_net_id_);
	}

	std::vector<PacketFeedback>
	TransportFeedbackAdapter::ProcessTransportFeedbackInner(
	const rtcp::TransportFeedback& feedback,
	Timestamp feedback_time) {
	// Add timestamp deltas to a local time base selected on first packet arrival.
	// This won't be the true time base, but makes it easier to manually inspect
	// time stamps.
	if (last_timestamp_.IsInfinite()) {
	current_offset_ = feedback_time;
	} else {
	// TODO(srte): We shouldn't need to do rounding here.
	const TimeDelta delta = feedback.GetBaseDelta(last_timestamp_)
	.RoundDownTo(TimeDelta::Millis<1>());
	// Protect against assigning current_offset_ negative value.
	if (delta < Timestamp::Zero() - current_offset_) {
	RTC_LOG(LS_WARNING) << "Unexpected feedback timestamp received.";
	current_offset_ = feedback_time;
	} else {
	current_offset_ += delta;
	}
	}
	last_timestamp_ = feedback.GetBaseTime();

	std::vector<PacketFeedback> packet_feedback_vector;
	packet_feedback_vector.reserve(feedback.GetPacketStatusCount());

	size_t failed_lookups = 0;
	size_t ignored = 0;
	TimeDelta packet_offset = TimeDelta::Zero();
	for (const auto& packet : feedback.GetAllPackets()) {
	int64_t seq_num = seq_num_unwrapper_.Unwrap(packet.sequence_number());

	if (seq_num > last_ack_seq_num_) {
	// Starts at history_.begin() if last_ack_seq_num_ < 0, since any valid
	// sequence number is >= 0.
	for (auto it = history_.upper_bound(last_ack_seq_num_);
	it != history_.upper_bound(seq_num); ++it) {
	in_flight_.RemoveInFlightPacketBytes(it->second);
	}
	last_ack_seq_num_ = seq_num;
	}

	auto it = history_.find(seq_num);
	if (it == history_.end()) {
	++failed_lookups;
	continue;
	}

	if (it->second.sent.send_time.IsInfinite()) {
	// TODO(srte): Fix the tests that makes this happen and make this a
	// DCHECK.
	RTC_DLOG(LS_ERROR)
	<< "Received feedback before packet was indicated as sent";
	continue;
	}

	PacketFeedback packet_feedback = it->second;
	if (packet.received()) {
	packet_offset += packet.delta();
	packet_feedback.receive_time =
	current_offset_ + packet_offset.RoundDownTo(TimeDelta::Millis<1>());
	// Note: Lost packets are not removed from history because they might be
	// reported as received by a later feedback.
	history_.erase(it);
	}
	if (packet_feedback.local_net_id == local_net_id_ &&
	packet_feedback.remote_net_id == remote_net_id_) {
	packet_feedback_vector.push_back(packet_feedback);
	} else {
	++ignored;
	}
	}

	if (failed_lookups > 0) {
	RTC_LOG(LS_WARNING) << "Failed to lookup send time for " << failed_lookups
	<< " packet" << (failed_lookups > 1 ? "s" : "")
	<< ". Send time history too small?";
	}
	if (ignored > 0) {
	RTC_LOG(LS_INFO) << "Ignoring " << ignored
	<< " packets because they were sent on a different route.";
	}

	return packet_feedback_vector;
	}

	void TransportFeedbackAdapter::SignalObservers(
	const std::vector<PacketFeedback>& feedback_vector) {
	rtc::CritScope cs(&observers_lock_);
	for (auto& observer : observers_) {
	std::vector<StreamFeedbackObserver::StreamPacketInfo> selected_feedback;
	for (const auto& packet : feedback_vector) {
	if (packet.ssrc && absl::c_count(observer.first, *packet.ssrc) > 0) {
	StreamFeedbackObserver::StreamPacketInfo packet_info;
	packet_info.ssrc = *packet.ssrc;
	packet_info.rtp_sequence_number = packet.rtp_sequence_number;
	packet_info.received = packet.receive_time.IsFinite();
	selected_feedback.push_back(packet_info);
	}
	}
	if (!selected_feedback.empty()) {
	observer.second->OnPacketFeedbackVector(std::move(selected_feedback));
	}
	}
	}

	} // namespace webrtc