modules/congestion_controller/transport_feedback_adapter.cc - src/webrtc - 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 "webrtc/modules/congestion_controller/transport_feedback_adapter.h"

 #include <algorithm>

 #include "webrtc/modules/congestion_controller/delay_based_bwe.h"
 #include "webrtc/modules/rtp_rtcp/source/rtcp_packet/transport_feedback.h"
 #include "webrtc/rtc_base/checks.h"
 #include "webrtc/rtc_base/logging.h"
 #include "webrtc/rtc_base/mod_ops.h"
 #include "webrtc/system_wrappers/include/field_trial.h"

 namespace webrtc {

 const int64_t kNoTimestamp = -1;
 const int64_t kSendTimeHistoryWindowMs = 60000;
 const int64_t kBaseTimestampScaleFactor =
     rtcp::TransportFeedback::kDeltaScaleFactor * (1 << 8);
 const int64_t kBaseTimestampRangeSizeUs = kBaseTimestampScaleFactor * (1 << 24);

 TransportFeedbackAdapter::TransportFeedbackAdapter(const Clock* clock)
     : send_side_bwe_with_overhead_(
           webrtc::field_trial::IsEnabled("WebRTC-SendSideBwe-WithOverhead")),
       transport_overhead_bytes_per_packet_(0),
       send_time_history_(clock, kSendTimeHistoryWindowMs),
       clock_(clock),
       current_offset_ms_(kNoTimestamp),
       last_timestamp_us_(kNoTimestamp),
       local_net_id_(0),
       remote_net_id_(0) {}

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

 void TransportFeedbackAdapter::RegisterPacketFeedbackObserver(
     PacketFeedbackObserver* observer) {
   rtc::CritScope cs(&observers_lock_);
   RTC_DCHECK(observer);
   RTC_DCHECK(std::find(observers_.begin(), observers_.end(), observer) ==
              observers_.end());
   observers_.push_back(observer);
 }

 void TransportFeedbackAdapter::DeRegisterPacketFeedbackObserver(
     PacketFeedbackObserver* observer) {
   rtc::CritScope cs(&observers_lock_);
   RTC_DCHECK(observer);
   const auto it = std::find(observers_.begin(), observers_.end(), observer);
   RTC_DCHECK(it != observers_.end());
   observers_.erase(it);
 }

 void TransportFeedbackAdapter::AddPacket(uint32_t ssrc,
                                          uint16_t sequence_number,
                                          size_t length,
                                          const PacedPacketInfo& pacing_info) {
   {
     rtc::CritScope cs(&lock_);
     if (send_side_bwe_with_overhead_) {
       length += transport_overhead_bytes_per_packet_;
     }
     const int64_t creation_time_ms = clock_->TimeInMilliseconds();
     send_time_history_.AddAndRemoveOld(
         PacketFeedback(creation_time_ms, sequence_number, length, local_net_id_,
                        remote_net_id_, pacing_info));
   }

   {
     rtc::CritScope cs(&observers_lock_);
     for (auto observer : observers_) {
       observer->OnPacketAdded(ssrc, sequence_number);
     }
   }
 }

 void TransportFeedbackAdapter::OnSentPacket(uint16_t sequence_number,
                                             int64_t send_time_ms) {
   rtc::CritScope cs(&lock_);
   send_time_history_.OnSentPacket(sequence_number, send_time_ms);
 }

 void TransportFeedbackAdapter::SetTransportOverhead(
     int transport_overhead_bytes_per_packet) {
   rtc::CritScope cs(&lock_);
   transport_overhead_bytes_per_packet_ = transport_overhead_bytes_per_packet;
 }

 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;
 }

 std::vector<PacketFeedback> TransportFeedbackAdapter::GetPacketFeedbackVector(
     const rtcp::TransportFeedback& feedback) {
   int64_t timestamp_us = feedback.GetBaseTimeUs();
   int64_t now_ms = clock_->TimeInMilliseconds();
   // 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_us_ == kNoTimestamp) {
     current_offset_ms_ = now_ms;
   } else {
     int64_t delta = timestamp_us - last_timestamp_us_;

     // Detect and compensate for wrap-arounds in base time.
     if (std::abs(delta - kBaseTimestampRangeSizeUs) < std::abs(delta)) {
       delta -= kBaseTimestampRangeSizeUs;  // Wrap backwards.
     } else if (std::abs(delta + kBaseTimestampRangeSizeUs) < std::abs(delta)) {
       delta += kBaseTimestampRangeSizeUs;  // Wrap forwards.
     }

     current_offset_ms_ += delta / 1000;
   }
   last_timestamp_us_ = timestamp_us;

   std::vector<PacketFeedback> packet_feedback_vector;
   if (feedback.GetPacketStatusCount() == 0) {
     LOG(LS_INFO) << "Empty transport feedback packet received.";
     return packet_feedback_vector;
   }
   packet_feedback_vector.reserve(feedback.GetPacketStatusCount());
   int64_t feedback_rtt = -1;
   {
     rtc::CritScope cs(&lock_);
     size_t failed_lookups = 0;
     int64_t offset_us = 0;
     int64_t timestamp_ms = 0;
     uint16_t seq_num = feedback.GetBaseSequence();
     for (const auto& packet : feedback.GetReceivedPackets()) {
       // Insert into the vector those unreceived packets which precede this
       // iteration's received packet.
       for (; seq_num != packet.sequence_number(); ++seq_num) {
         PacketFeedback packet_feedback(PacketFeedback::kNotReceived, seq_num);
         // Note: Element not removed from history because it might be reported
         // as received by another feedback.
         if (!send_time_history_.GetFeedback(&packet_feedback, false))
           ++failed_lookups;
         if (packet_feedback.local_net_id == local_net_id_ &&
             packet_feedback.remote_net_id == remote_net_id_) {
           packet_feedback_vector.push_back(packet_feedback);
         }
       }

       // Handle this iteration's received packet.
       offset_us += packet.delta_us();
       timestamp_ms = current_offset_ms_ + (offset_us / 1000);
       PacketFeedback packet_feedback(timestamp_ms, packet.sequence_number());
       if (!send_time_history_.GetFeedback(&packet_feedback, true))
         ++failed_lookups;
       if (packet_feedback.local_net_id == local_net_id_ &&
           packet_feedback.remote_net_id == remote_net_id_) {
         if (packet_feedback.send_time_ms >= 0) {
           int64_t rtt = now_ms - packet_feedback.send_time_ms;
           // max() is used to account for feedback being delayed by the
           // receiver.
           feedback_rtt = std::max(rtt, feedback_rtt);
         }
         packet_feedback_vector.push_back(packet_feedback);
       }

       ++seq_num;
     }

     if (failed_lookups > 0) {
       LOG(LS_WARNING) << "Failed to lookup send time for " << failed_lookups
                       << " packet" << (failed_lookups > 1 ? "s" : "")
                       << ". Send time history too small?";
     }
     if (feedback_rtt > -1) {
       feedback_rtts_.push_back(feedback_rtt);
       const size_t kFeedbackRttWindow = 32;
       if (feedback_rtts_.size() > kFeedbackRttWindow)
         feedback_rtts_.pop_front();
       min_feedback_rtt_.emplace(
           *std::min_element(feedback_rtts_.begin(), feedback_rtts_.end()));
     }
   }
   return packet_feedback_vector;
 }

 void TransportFeedbackAdapter::OnTransportFeedback(
     const rtcp::TransportFeedback& feedback) {
   last_packet_feedback_vector_ = GetPacketFeedbackVector(feedback);
   {
     rtc::CritScope cs(&observers_lock_);
     for (auto observer : observers_) {
       observer->OnPacketFeedbackVector(last_packet_feedback_vector_);
     }
   }
 }

 std::vector<PacketFeedback>
 TransportFeedbackAdapter::GetTransportFeedbackVector() const {
   return last_packet_feedback_vector_;
 }

 rtc::Optional<int64_t> TransportFeedbackAdapter::GetMinFeedbackLoopRtt() const {
   rtc::CritScope cs(&lock_);
   return min_feedback_rtt_;
 }

 size_t TransportFeedbackAdapter::GetOutstandingBytes() const {
   rtc::CritScope cs(&lock_);
   return send_time_history_.GetOutstandingBytes(local_net_id_, remote_net_id_);
 }
 }  // 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 "webrtc/modules/congestion_controller/transport_feedback_adapter.h"

	#include <algorithm>

	#include "webrtc/modules/congestion_controller/delay_based_bwe.h"
	#include "webrtc/modules/rtp_rtcp/source/rtcp_packet/transport_feedback.h"
	#include "webrtc/rtc_base/checks.h"
	#include "webrtc/rtc_base/logging.h"
	#include "webrtc/rtc_base/mod_ops.h"
	#include "webrtc/system_wrappers/include/field_trial.h"

	namespace webrtc {

	const int64_t kNoTimestamp = -1;
	const int64_t kSendTimeHistoryWindowMs = 60000;
	const int64_t kBaseTimestampScaleFactor =
	rtcp::TransportFeedback::kDeltaScaleFactor * (1 << 8);
	const int64_t kBaseTimestampRangeSizeUs = kBaseTimestampScaleFactor * (1 << 24);

	TransportFeedbackAdapter::TransportFeedbackAdapter(const Clock* clock)
	: send_side_bwe_with_overhead_(
	webrtc::field_trial::IsEnabled("WebRTC-SendSideBwe-WithOverhead")),
	transport_overhead_bytes_per_packet_(0),
	send_time_history_(clock, kSendTimeHistoryWindowMs),
	clock_(clock),
	current_offset_ms_(kNoTimestamp),
	last_timestamp_us_(kNoTimestamp),
	local_net_id_(0),
	remote_net_id_(0) {}

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

	void TransportFeedbackAdapter::RegisterPacketFeedbackObserver(
	PacketFeedbackObserver* observer) {
	rtc::CritScope cs(&observers_lock_);
	RTC_DCHECK(observer);
	RTC_DCHECK(std::find(observers_.begin(), observers_.end(), observer) ==
	observers_.end());
	observers_.push_back(observer);
	}

	void TransportFeedbackAdapter::DeRegisterPacketFeedbackObserver(
	PacketFeedbackObserver* observer) {
	rtc::CritScope cs(&observers_lock_);
	RTC_DCHECK(observer);
	const auto it = std::find(observers_.begin(), observers_.end(), observer);
	RTC_DCHECK(it != observers_.end());
	observers_.erase(it);
	}

	void TransportFeedbackAdapter::AddPacket(uint32_t ssrc,
	uint16_t sequence_number,
	size_t length,
	const PacedPacketInfo& pacing_info) {
	{
	rtc::CritScope cs(&lock_);
	if (send_side_bwe_with_overhead_) {
	length += transport_overhead_bytes_per_packet_;
	}
	const int64_t creation_time_ms = clock_->TimeInMilliseconds();
	send_time_history_.AddAndRemoveOld(
	PacketFeedback(creation_time_ms, sequence_number, length, local_net_id_,
	remote_net_id_, pacing_info));
	}

	{
	rtc::CritScope cs(&observers_lock_);
	for (auto observer : observers_) {
	observer->OnPacketAdded(ssrc, sequence_number);
	}
	}
	}

	void TransportFeedbackAdapter::OnSentPacket(uint16_t sequence_number,
	int64_t send_time_ms) {
	rtc::CritScope cs(&lock_);
	send_time_history_.OnSentPacket(sequence_number, send_time_ms);
	}

	void TransportFeedbackAdapter::SetTransportOverhead(
	int transport_overhead_bytes_per_packet) {
	rtc::CritScope cs(&lock_);
	transport_overhead_bytes_per_packet_ = transport_overhead_bytes_per_packet;
	}

	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;
	}

	std::vector<PacketFeedback> TransportFeedbackAdapter::GetPacketFeedbackVector(
	const rtcp::TransportFeedback& feedback) {
	int64_t timestamp_us = feedback.GetBaseTimeUs();
	int64_t now_ms = clock_->TimeInMilliseconds();
	// 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_us_ == kNoTimestamp) {
	current_offset_ms_ = now_ms;
	} else {
	int64_t delta = timestamp_us - last_timestamp_us_;

	// Detect and compensate for wrap-arounds in base time.
	if (std::abs(delta - kBaseTimestampRangeSizeUs) < std::abs(delta)) {
	delta -= kBaseTimestampRangeSizeUs; // Wrap backwards.
	} else if (std::abs(delta + kBaseTimestampRangeSizeUs) < std::abs(delta)) {
	delta += kBaseTimestampRangeSizeUs; // Wrap forwards.
	}

	current_offset_ms_ += delta / 1000;
	}
	last_timestamp_us_ = timestamp_us;

	std::vector<PacketFeedback> packet_feedback_vector;
	if (feedback.GetPacketStatusCount() == 0) {
	LOG(LS_INFO) << "Empty transport feedback packet received.";
	return packet_feedback_vector;
	}
	packet_feedback_vector.reserve(feedback.GetPacketStatusCount());
	int64_t feedback_rtt = -1;
	{
	rtc::CritScope cs(&lock_);
	size_t failed_lookups = 0;
	int64_t offset_us = 0;
	int64_t timestamp_ms = 0;
	uint16_t seq_num = feedback.GetBaseSequence();
	for (const auto& packet : feedback.GetReceivedPackets()) {
	// Insert into the vector those unreceived packets which precede this
	// iteration's received packet.
	for (; seq_num != packet.sequence_number(); ++seq_num) {
	PacketFeedback packet_feedback(PacketFeedback::kNotReceived, seq_num);
	// Note: Element not removed from history because it might be reported
	// as received by another feedback.
	if (!send_time_history_.GetFeedback(&packet_feedback, false))
	++failed_lookups;
	if (packet_feedback.local_net_id == local_net_id_ &&
	packet_feedback.remote_net_id == remote_net_id_) {
	packet_feedback_vector.push_back(packet_feedback);
	}
	}

	// Handle this iteration's received packet.
	offset_us += packet.delta_us();
	timestamp_ms = current_offset_ms_ + (offset_us / 1000);
	PacketFeedback packet_feedback(timestamp_ms, packet.sequence_number());
	if (!send_time_history_.GetFeedback(&packet_feedback, true))
	++failed_lookups;
	if (packet_feedback.local_net_id == local_net_id_ &&
	packet_feedback.remote_net_id == remote_net_id_) {
	if (packet_feedback.send_time_ms >= 0) {
	int64_t rtt = now_ms - packet_feedback.send_time_ms;
	// max() is used to account for feedback being delayed by the
	// receiver.
	feedback_rtt = std::max(rtt, feedback_rtt);
	}
	packet_feedback_vector.push_back(packet_feedback);
	}

	++seq_num;
	}

	if (failed_lookups > 0) {
	LOG(LS_WARNING) << "Failed to lookup send time for " << failed_lookups
	<< " packet" << (failed_lookups > 1 ? "s" : "")
	<< ". Send time history too small?";
	}
	if (feedback_rtt > -1) {
	feedback_rtts_.push_back(feedback_rtt);
	const size_t kFeedbackRttWindow = 32;
	if (feedback_rtts_.size() > kFeedbackRttWindow)
	feedback_rtts_.pop_front();
	min_feedback_rtt_.emplace(
	*std::min_element(feedback_rtts_.begin(), feedback_rtts_.end()));
	}
	}
	return packet_feedback_vector;
	}

	void TransportFeedbackAdapter::OnTransportFeedback(
	const rtcp::TransportFeedback& feedback) {
	last_packet_feedback_vector_ = GetPacketFeedbackVector(feedback);
	{
	rtc::CritScope cs(&observers_lock_);
	for (auto observer : observers_) {
	observer->OnPacketFeedbackVector(last_packet_feedback_vector_);
	}
	}
	}

	std::vector<PacketFeedback>
	TransportFeedbackAdapter::GetTransportFeedbackVector() const {
	return last_packet_feedback_vector_;
	}

	rtc::Optional<int64_t> TransportFeedbackAdapter::GetMinFeedbackLoopRtt() const {
	rtc::CritScope cs(&lock_);
	return min_feedback_rtt_;
	}

	size_t TransportFeedbackAdapter::GetOutstandingBytes() const {
	rtc::CritScope cs(&lock_);
	return send_time_history_.GetOutstandingBytes(local_net_id_, remote_net_id_);
	}
	} // namespace webrtc