Cast: reduce the amount of retransmission packets

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 75 matching lines @@
     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>(frame.referenced_frame_id));
 
     // Copy payload data.
     packet->data.insert(packet->data.end(),
                         data_iter,
                         data_iter + payload_length);
+    data_iter += payload_length;
 
-    PacketKey key = PacedPacketSender::MakePacketKey(frame.reference_time,
-                                                     config_.ssrc,
-                                                     packet_id_);
-
-    // Store packet.
-    packet_storage_->StorePacket(frame.frame_id, packet_id_, key, packet);
-    ++packet_id_;
-    data_iter += payload_length;
+    const PacketKey key =
+        PacedPacketSender::MakePacketKey(frame.reference_time,
+                                         config_.ssrc,
+                                         packet_id_++);
+    packets.push_back(make_pair(key, packet));
 
     // Update stats.
     ++send_packet_count_;
     send_octet_count_ += payload_length;
-    packets.push_back(make_pair(key, packet));
   }
   DCHECK(packet_id_ == num_packets) << "Invalid state";
 
+  packet_storage_->StoreFrame(frame.frame_id, packets);
+
   // 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