Cast: Only ACK decodable frames

media/cast/video_receiver/video_receiver.cc

Index: media/cast/video_receiver/video_receiver.cc
diff --git a/media/cast/video_receiver/video_receiver.cc b/media/cast/video_receiver/video_receiver.cc
index 4af2c5316247cbbd4b58edd970b1c9d010958ea8..92267439008f3ecfc9ad19cb5fe791a99c4097a4 100644
--- a/media/cast/video_receiver/video_receiver.cc
+++ b/media/cast/video_receiver/video_receiver.cc
@@ -155,19 +155,30 @@ void VideoReceiver::EmitAvailableEncodedFrames() {
     scoped_ptr<transport::EncodedVideoFrame> encoded_frame(
         new transport::EncodedVideoFrame());
     bool is_consecutively_next_frame = false;
+    bool have_multiple_complete_frames = false;

[miu, 2014/05/16 19:45:25]

Please make these changes identically in AudioReceiver.  I promise I'll merge
the two shortly.  ;-)

[hubbe, 2014/05/16 20:50:58]

Done.

+
     if (!framer_.GetEncodedVideoFrame(encoded_frame.get(),
-                                      &is_consecutively_next_frame)) {
+                                      &is_consecutively_next_frame,
+                                      &have_multiple_complete_frames)) {
       VLOG(1) << "Wait for more video packets to produce a completed frame.";
       return;  // OnReceivedPayloadData() will invoke this method in the future.
     }
 
+    const base::TimeTicks now = cast_environment_->Clock()->NowTicks();
+    const base::TimeTicks playout_time =
+        GetPlayoutTime(now, encoded_frame->rtp_timestamp);
+
+    // If we have multiple decodable frames, and the current frame is
+    // too old, then skip it and decode the next frame instead.
+    if (have_multiple_complete_frames && now > playout_time) {
+      framer_.ReleaseFrame(encoded_frame->frame_id);
+      continue;
+    }
+
     // If |framer_| has a frame ready that is out of sequence, examine the
     // playout time to determine whether it's acceptable to continue, thereby
     // skipping one or more frames.  Skip if the missing frame wouldn't complete
     // playing before the start of playback of the available frame.
-    const base::TimeTicks now = cast_environment_->Clock()->NowTicks();
-    const base::TimeTicks playout_time =
-        GetPlayoutTime(now, encoded_frame->rtp_timestamp);
     if (!is_consecutively_next_frame) {
       // TODO(miu): Also account for expected decode time here?
       const base::TimeTicks earliest_possible_end_time_of_missing_frame =