Cast: end2end bug fixes

media/cast/video_receiver/video_receiver.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/video_receiver/video_receiver.h"
 
 #include <algorithm>
 
 #include "base/bind.h"
 #include "base/logging.h"
@@ skipping 349 matching lines @@
   // to wait for new packet(s).
 }
 
 base::TimeTicks VideoReceiver::GetRenderTime(base::TimeTicks now,
                                              uint32 rtp_timestamp) {
   DCHECK(cast_environment_->CurrentlyOn(CastEnvironment::MAIN));
   // Senders time in ms when this frame was captured.
   // Note: the senders clock and our local clock might not be synced.
   base::TimeTicks rtp_timestamp_in_ticks;
 
+  // Compute the time offset_in_ticks based on the incoming_rtp_timestamp_.
   if (time_offset_.InMilliseconds() == 0) {
     if (!rtcp_->RtpTimestampInSenderTime(kVideoFrequency,
                                          incoming_rtp_timestamp_,
                                          &rtp_timestamp_in_ticks)) {
       // We have not received any RTCP to sync the stream play it out as soon as
       // possible.
       return now;
     }
     time_offset_ = time_incoming_packet_ - rtp_timestamp_in_ticks;
   } else if (time_incoming_packet_updated_) {
     if (rtcp_->RtpTimestampInSenderTime(kVideoFrequency,
                                         incoming_rtp_timestamp_,
                                         &rtp_timestamp_in_ticks)) {
       // Time to update the time_offset.
       base::TimeDelta time_offset =
           time_incoming_packet_ - rtp_timestamp_in_ticks;
       time_offset_ = ((kTimeOffsetFilter - 1) * time_offset_ + time_offset) /
                      kTimeOffsetFilter;
     }
   }
   // Reset |time_incoming_packet_updated_| to enable a future measurement.
   time_incoming_packet_updated_ = false;
+  // Compute the actual rtp_timestamp_in_ticks based on the current timestamp.
   if (!rtcp_->RtpTimestampInSenderTime(
            kVideoFrequency, rtp_timestamp, &rtp_timestamp_in_ticks)) {
     // This can fail if we have not received any RTCP packets in a long time.
     return now;
   }
   base::TimeTicks render_time =
       rtp_timestamp_in_ticks + time_offset_ + target_delay_delta_;
   if (last_render_time_ > render_time)
     render_time = last_render_time_;
   last_render_time_ = render_time;
@@ skipping 122 matching lines @@
 }
 
 void VideoReceiver::SendNextRtcpReport() {
   DCHECK(cast_environment_->CurrentlyOn(CastEnvironment::MAIN));
   rtcp_->SendRtcpFromRtpReceiver(NULL, NULL);
   ScheduleNextRtcpReport();
 }
 
 }  // namespace cast
 }  // namespace media