Cast: Move retransmission to the transport

media/cast/sender/video_sender.cc

 // Copyright 2014 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/sender/video_sender.h"
 
 #include <algorithm>
 #include <cstring>
 
 #include "base/bind.h"
@@ skipping 264 matching lines @@
     }
     // TODO(miu): The values "2" and "3" should be derived from configuration.
     if (duplicate_ack_counter_ >= 2 && duplicate_ack_counter_ % 3 == 2) {
       VLOG(1) << "Received duplicate ACK for frame " << latest_acked_frame_id_;
       ResendForKickstart();
     }
   } else {
     // Only count duplicated ACKs if there is no NACK request in between.
     // This is to avoid aggresive resend.
     duplicate_ack_counter_ = 0;
-
-    // A NACK is also used to cancel pending re-transmissions.
-    transport_sender_->ResendPackets(
-        false, cast_feedback.missing_frames_and_packets, true, rtt);
   }
 
   base::TimeTicks now = cast_environment_->Clock()->NowTicks();
   congestion_control_.AckFrame(cast_feedback.ack_frame_id, now);
 
   RtpTimestamp rtp_timestamp =
       frame_id_to_rtp_timestamp_[cast_feedback.ack_frame_id & 0xff];
   cast_environment_->Logging()->InsertFrameEvent(now,
                                                  FRAME_ACK_RECEIVED,
                                                  VIDEO_EVENT,
                                                  rtp_timestamp,
                                                  cast_feedback.ack_frame_id);
 
   const bool is_acked_out_of_order =
       static_cast<int32>(cast_feedback.ack_frame_id -
                              latest_acked_frame_id_) < 0;
   VLOG(2) << "Received ACK" << (is_acked_out_of_order ? " out-of-order" : "")
           << " for frame " << cast_feedback.ack_frame_id;
   if (!is_acked_out_of_order) {
     // Cancel resends of acked frames.
-    MissingFramesAndPacketsMap missing_frames_and_packets;
-    PacketIdSet missing;
+    std::set<uint32> cancel_sending_frames;

[hubbe, 2014/08/11 19:11:50]

Seems like a vector would be sufficient here.

     while (latest_acked_frame_id_ != cast_feedback.ack_frame_id) {
       latest_acked_frame_id_++;
-      missing_frames_and_packets[latest_acked_frame_id_] = missing;
+      cancel_sending_frames.insert(latest_acked_frame_id_);
     }
-    transport_sender_->ResendPackets(
-        false, missing_frames_and_packets, true, rtt);
+    transport_sender_->CancelSendingFrames(ssrc_, cancel_sending_frames);
     latest_acked_frame_id_ = cast_feedback.ack_frame_id;
   }
 }
 
 bool VideoSender::AreTooManyFramesInFlight() const {
   DCHECK(cast_environment_->CurrentlyOn(CastEnvironment::MAIN));
   int frames_in_flight = frames_in_encoder_;
   if (!last_send_time_.is_null()) {
     frames_in_flight +=
         static_cast<int32>(last_sent_frame_id_ - latest_acked_frame_id_);
   }
   VLOG(2) << frames_in_flight
           << " frames in flight; last sent: " << last_sent_frame_id_
           << " latest acked: " << latest_acked_frame_id_
           << " frames in encoder: " << frames_in_encoder_;
   return frames_in_flight >= max_unacked_frames_;
 }
 
 void VideoSender::ResendForKickstart() {
   DCHECK(cast_environment_->CurrentlyOn(CastEnvironment::MAIN));
   DCHECK(!last_send_time_.is_null());
   VLOG(1) << "Resending last packet of frame " << last_sent_frame_id_
           << " to kick-start.";
-  // Send the first packet of the last encoded frame to kick start
-  // retransmission. This gives enough information to the receiver what
-  // packets and frames are missing.
-  MissingFramesAndPacketsMap missing_frames_and_packets;
-  PacketIdSet missing;
-  missing.insert(kRtcpCastLastPacket);
-  missing_frames_and_packets.insert(
-      std::make_pair(last_sent_frame_id_, missing));
   last_send_time_ = cast_environment_->Clock()->NowTicks();
-
-  // Sending this extra packet is to kick-start the session. There is
-  // no need to optimize re-transmission for this case.
-  transport_sender_->ResendPackets(false, missing_frames_and_packets,
-                                   false, rtt_);
+  transport_sender_->ResendFrameForKickstart(ssrc_, last_sent_frame_id_);
 }
 
 }  // namespace cast
 }  // namespace media