Parse FlexFEC RTP headers in Call and add integration with BWE.

webrtc/modules/rtp_rtcp/source/flexfec_receiver.cc

 /*
  *  Copyright (c) 2016 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/rtp_rtcp/include/flexfec_receiver.h"
 
 #include <utility>
 
 #include "webrtc/base/logging.h"
 #include "webrtc/base/scoped_ref_ptr.h"
-#include "webrtc/modules/rtp_rtcp/source/rtp_packet_received.h"
+#include "webrtc/modules/remote_bitrate_estimator/include/remote_bitrate_estimator.h"
+#include "webrtc/modules/rtp_rtcp/source/rtp_header_extensions.h"
 
 namespace webrtc {
 
 namespace {
 
 using Packet = ForwardErrorCorrection::Packet;
 using ReceivedPacket = ForwardErrorCorrection::ReceivedPacket;
 
 // Minimum header size (in bytes) of a well-formed non-singular FlexFEC packet.
 constexpr size_t kMinFlexfecHeaderSize = 20;
 
 // How often to log the recovered packets to the text log.
 constexpr int kPacketLogIntervalMs = 10000;
 
+bool HasBweExtension(const RtpPacketReceived& packet) {
+  return packet.HasExtension<TransportSequenceNumber>() ||
+         packet.HasExtension<AbsoluteSendTime>() ||
+         packet.HasExtension<TransmissionOffset>();
+}
+
 }  // namespace
 
-FlexfecReceiver::FlexfecReceiver(uint32_t ssrc,
-                                 uint32_t protected_media_ssrc,
-                                 RecoveredPacketReceiver* callback)
+FlexfecReceiver::FlexfecReceiver(
+    uint32_t ssrc,
+    uint32_t protected_media_ssrc,
+    RecoveredPacketReceiver* recovered_packet_receiver,
+    RemoteBitrateEstimator* remote_bitrate_estimator)
     : ssrc_(ssrc),
       protected_media_ssrc_(protected_media_ssrc),
       erasure_code_(ForwardErrorCorrection::CreateFlexfec()),
-      callback_(callback),
+      recovered_packet_receiver_(recovered_packet_receiver),
+      remote_bitrate_estimator_(remote_bitrate_estimator),
       clock_(Clock::GetRealTimeClock()),
       last_recovered_packet_ms_(-1) {
   // It's OK to create this object on a different thread/task queue than
   // the one used during main operation.
   sequence_checker_.Detach();
 }
 
 FlexfecReceiver::~FlexfecReceiver() = default;
 
-bool FlexfecReceiver::AddAndProcessReceivedPacket(const uint8_t* packet,
-                                                  size_t packet_length) {
+bool FlexfecReceiver::AddAndProcessReceivedPacket(RtpPacketReceived packet) {
   RTC_DCHECK(sequence_checker_.CalledSequentially());
 
-  if (!AddReceivedPacket(packet, packet_length)) {
+  if (!AddReceivedPacket(std::move(packet))) {
     return false;
   }
   return ProcessReceivedPackets();
 }
 
 FecPacketCounter FlexfecReceiver::GetPacketCounter() const {
   RTC_DCHECK(sequence_checker_.CalledSequentially());
   return packet_counter_;
 }
 
-bool FlexfecReceiver::AddReceivedPacket(const uint8_t* packet,
-                                        size_t packet_length) {
+bool FlexfecReceiver::AddReceivedPacket(RtpPacketReceived packet) {
   RTC_DCHECK(sequence_checker_.CalledSequentially());
 
   // RTP packets with a full base header (12 bytes), but without payload,
   // could conceivably be useful in the decoding. Therefore we check
-  // with a strict inequality here.
-  if (packet_length < kRtpHeaderSize) {
-    LOG(LS_WARNING) << "Truncated packet, discarding.";
-    return false;
-  }
-
-  // TODO(brandtr): Consider how to handle received FlexFEC packets and
-  // the bandwidth estimator.
-  RtpPacketReceived parsed_packet;
-  if (!parsed_packet.Parse(packet, packet_length)) {
-    return false;
-  }
+  // with a non-strict inequality here.
+  RTC_DCHECK_GE(packet.size(), kRtpHeaderSize);
 
   // Demultiplex based on SSRC, and insert into erasure code decoder.
   std::unique_ptr<ReceivedPacket> received_packet(new ReceivedPacket());
-  received_packet->seq_num = parsed_packet.SequenceNumber();
-  received_packet->ssrc = parsed_packet.Ssrc();
+  received_packet->seq_num = packet.SequenceNumber();
+  received_packet->ssrc = packet.Ssrc();
   if (received_packet->ssrc == ssrc_) {
-    // This is a FEC packet belonging to this FlexFEC stream.
-    if (parsed_packet.payload_size() < kMinFlexfecHeaderSize) {
+    // This is a FlexFEC packet.
+    if (packet.payload_size() < kMinFlexfecHeaderSize) {
       LOG(LS_WARNING) << "Truncated FlexFEC packet, discarding.";
       return false;
     }
     received_packet->is_fec = true;
     ++packet_counter_.num_fec_packets;
+
+    // Notify BWE.

[danilchap, 2016/12/13 14:11:24]

why is it done all the way down here rather than in call?

[brandtr, 2016/12/14 12:55:49]

I forgot that Call demuxes based on SSRC, so we could notify the BWE at that
level.

The reason that I put it here originally is that FlexfecReceiver also demuxes
based on SSRC, whereas FlexfecReceiveStream does not.

+    if (HasBweExtension(packet)) {
+      RTPHeader header;
+      packet.GetHeader(&header);
+      remote_bitrate_estimator_->IncomingPacket(packet.arrival_time_ms(),
+                                                packet.payload_size(), header);
+    }
+
     // Insert packet payload into erasure code.
     // TODO(brandtr): Remove this memcpy when the FEC packet classes
     // are using COW buffers internally.
     received_packet->pkt = rtc::scoped_refptr<Packet>(new Packet());
-    auto payload = parsed_packet.payload();
+    auto payload = packet.payload();
     memcpy(received_packet->pkt->data, payload.data(), payload.size());
     received_packet->pkt->length = payload.size();
   } else {
     // This is a media packet, or a FlexFEC packet belonging to some
     // other FlexFEC stream.
     if (received_packet->ssrc != protected_media_ssrc_) {
       return false;
     }
     received_packet->is_fec = false;
+
     // Insert entire packet into erasure code.
     // TODO(brandtr): Remove this memcpy too.
     received_packet->pkt = rtc::scoped_refptr<Packet>(new Packet());
-    memcpy(received_packet->pkt->data, parsed_packet.data(),
-           parsed_packet.size());
-    received_packet->pkt->length = parsed_packet.size();
+    memcpy(received_packet->pkt->data, packet.data(), packet.size());
+    received_packet->pkt->length = packet.size();
   }
+
   received_packets_.push_back(std::move(received_packet));
   ++packet_counter_.num_packets;
 
   return true;
 }
 
 // Note that the implementation of this member function and the implementation
 // in UlpfecReceiver::ProcessReceivedFec() are slightly different.
 // This implementation only returns _recovered_ media packets through the
 // callback, whereas the implementation in UlpfecReceiver returns _all inserted_
@@ skipping 11 matching lines @@
         0) {
       return false;
     }
   }
   // Return recovered packets through callback.
   for (const auto& recovered_packet : recovered_packets_) {
     if (recovered_packet->returned) {
       continue;
     }
     ++packet_counter_.num_recovered_packets;
-    if (!callback_->OnRecoveredPacket(recovered_packet->pkt->data,
-                                      recovered_packet->pkt->length)) {
+    if (!recovered_packet_receiver_->OnRecoveredPacket(
+            recovered_packet->pkt->data, recovered_packet->pkt->length)) {
       return false;
     }
     recovered_packet->returned = true;
     // Periodically log the incoming packets.
     int64_t now_ms = clock_->TimeInMilliseconds();
     if (now_ms - last_recovered_packet_ms_ > kPacketLogIntervalMs) {
       uint32_t media_ssrc =
           ForwardErrorCorrection::ParseSsrc(recovered_packet->pkt->data);
       LOG(LS_INFO) << "Recovered media packet with SSRC: " << media_ssrc
                    << " from FlexFEC stream with SSRC: " << ssrc_ << ".";
       last_recovered_packet_ms_ = now_ms;
     }
   }
   return true;
 }
 
 }  // namespace webrtc