Cast: Deduplicate packets in paced sender and always send older packets first

media/cast/transport/rtp_sender/rtp_packetizer/rtp_packetizer.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "media/cast/transport/rtp_sender/rtp_packetizer/rtp_packetizer.h"
 
 #include "base/big_endian.h"
 #include "base/logging.h"
 #include "media/cast/transport/pacing/paced_sender.h"
 
@@ skipping 38 matching lines @@
 
 RtpPacketizer::~RtpPacketizer() {}
 
 void RtpPacketizer::IncomingEncodedVideoFrame(
     const EncodedVideoFrame* video_frame,
     const base::TimeTicks& capture_time) {
   DCHECK(!config_.audio) << "Invalid state";
   if (config_.audio)
     return;
 
-  time_last_sent_rtp_timestamp_ = capture_time;
   Cast(video_frame->key_frame,
        video_frame->frame_id,
        video_frame->last_referenced_frame_id,
        video_frame->rtp_timestamp,
-       video_frame->data);
+       video_frame->data,
+       capture_time);
 }
 
 void RtpPacketizer::IncomingEncodedAudioFrame(
     const EncodedAudioFrame* audio_frame,
     const base::TimeTicks& recorded_time) {
   DCHECK(config_.audio) << "Invalid state";
   if (!config_.audio)
     return;
 
-  time_last_sent_rtp_timestamp_ = recorded_time;
   Cast(true,
        audio_frame->frame_id,
        0,
        audio_frame->rtp_timestamp,
-       audio_frame->data);
+       audio_frame->data,
+       recorded_time);
 }
 
 uint16 RtpPacketizer::NextSequenceNumber() {
   ++sequence_number_;
   return sequence_number_ - 1;
 }
 
 bool RtpPacketizer::LastSentTimestamp(base::TimeTicks* time_sent,
                                       uint32* rtp_timestamp) const {
   if (time_last_sent_rtp_timestamp_.is_null())
     return false;
 
   *time_sent = time_last_sent_rtp_timestamp_;
   *rtp_timestamp = rtp_timestamp_;
   return true;
 }
 
 // TODO(mikhal): Switch to pass data with a const_ref.
 void RtpPacketizer::Cast(bool is_key,
                          uint32 frame_id,
                          uint32 reference_frame_id,
                          uint32 timestamp,
-                         const std::string& data) {
+                         const std::string& data,
+                         const base::TimeTicks& capture_time) {
+  time_last_sent_rtp_timestamp_ = capture_time;
   uint16 rtp_header_length = kCommonRtpHeaderLength + kCastRtpHeaderLength;
   uint16 max_length = config_.max_payload_length - rtp_header_length - 1;
   rtp_timestamp_ = timestamp;
 
   // Split the payload evenly (round number up).
   size_t num_packets = (data.size() + max_length) / max_length;
   size_t payload_length = (data.size() + num_packets) / num_packets;
   DCHECK_LE(payload_length, max_length) << "Invalid argument";
 
-  PacketList packets;
+  SendPacketVector packets;
+  PacketList packets_for_logging;
 
   size_t remaining_size = data.size();
   std::string::const_iterator data_iter = data.begin();
   while (remaining_size > 0) {
     PacketRef packet(new base::RefCountedData<Packet>);
 
     if (remaining_size < payload_length) {
       payload_length = remaining_size;
     }
     remaining_size -= payload_length;
     BuildCommonRTPheader(&packet->data, remaining_size == 0, timestamp);
 
     // Build Cast header.
     packet->data.push_back((is_key ? kCastKeyFrameBitMask : 0) |
                            kCastReferenceFrameIdBitMask);
     packet->data.push_back(frame_id);
     size_t start_size = packet->data.size();
     packet->data.resize(start_size + 4);
     base::BigEndianWriter big_endian_writer(
         reinterpret_cast<char*>(&(packet->data[start_size])), 4);
     big_endian_writer.WriteU16(packet_id_);
     big_endian_writer.WriteU16(static_cast<uint16>(num_packets - 1));
     packet->data.push_back(static_cast<uint8>(reference_frame_id));
 
     // Copy payload data.
     packet->data.insert(packet->data.end(),
                         data_iter,
                         data_iter + payload_length);
 
+    PacketKey key = PacedPacketSender::MakePacketKey(capture_time,
+                                                     config_.ssrc,
+                                                     packet_id_);
+
     // Store packet.
-    packet_storage_->StorePacket(frame_id, packet_id_, packet);
+    packet_storage_->StorePacket(frame_id, packet_id_, key, packet);
     ++packet_id_;
     data_iter += payload_length;
 
     // Update stats.
     ++send_packets_count_;
     send_octet_count_ += payload_length;
-    packets.push_back(packet);
+    packets.push_back(make_pair(key, packet));
+    packets_for_logging.push_back(packet);
   }
   DCHECK(packet_id_ == num_packets) << "Invalid state";
 
   logging_->InsertPacketListEvent(
       clock_->NowTicks(),
       config_.audio ? kAudioPacketSentToPacer : kVideoPacketSentToPacer,
-      packets);
+      packets_for_logging);
 
   // Send to network.
   transport_->SendPackets(packets);
 
   // Prepare for next frame.
   packet_id_ = 0;
 }
 
 void RtpPacketizer::BuildCommonRTPheader(Packet* packet,
                                          bool marker_bit,
                                          uint32 time_stamp) {
   packet->push_back(0x80);
   packet->push_back(static_cast<uint8>(config_.payload_type) |
                     (marker_bit ? kRtpMarkerBitMask : 0));
   size_t start_size = packet->size();
   packet->resize(start_size + 10);
   base::BigEndianWriter big_endian_writer(
       reinterpret_cast<char*>(&((*packet)[start_size])), 10);
   big_endian_writer.WriteU16(sequence_number_);
   big_endian_writer.WriteU32(time_stamp);
   big_endian_writer.WriteU32(config_.ssrc);
   ++sequence_number_;
 }
 
 }  // namespace transport
 }  // namespace cast
 }  // namespace media