Add Cast PLI support on sender side.

media/cast/net/rtcp/receiver_rtcp_session.cc

 // Copyright 2015 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 "base/big_endian.h"
 #include "base/time/tick_clock.h"
 #include "media/cast/net/pacing/paced_sender.h"
 #include "media/cast/net/rtcp/receiver_rtcp_session.h"
 #include "media/cast/net/rtcp/rtcp_builder.h"
 #include "media/cast/net/rtcp/rtcp_defines.h"
@@ skipping 80 matching lines @@
     local_clock_ahead_by_.Reset(now, measured_offset);
   }
   VLOG(1) << "Local clock is ahead of the remote clock by: "
           << "measured=" << measured_offset.InMicroseconds() << " usec, "
           << "filtered=" << local_clock_ahead_by_.Current().InMicroseconds()
           << " usec.";
 }
 
 void ReceiverRtcpSession::SendRtcpReport(
     RtcpTimeData time_data,
     const RtcpCastMessage* cast_message,

[miu, 2016/02/26 23:36:06]

Instead of including |picture_loss_indicator| in |cast_message|, please specify
it as a separate argument here.

In the case where you want to send a PLI but not an RRTR, you should modify this
method to handle an optionally null |cast_message|.

[xjz, 2016/02/27 05:53:32]

Done.

     base::TimeDelta target_delay,
     const ReceiverRtcpEventSubscriber::RtcpEvents* rtcp_events,
     const RtpReceiverStatistics* rtp_receiver_statistics) const {
   RtcpReportBlock report_block;
   RtcpReceiverReferenceTimeReport rrtr;
-  rrtr.ntp_seconds = time_data.ntp_seconds;
-  rrtr.ntp_fraction = time_data.ntp_fraction;
-
+  if ((!cast_message) || (!cast_message->picture_loss_indicator)) {
+    rrtr.ntp_seconds = time_data.ntp_seconds;
+    rrtr.ntp_fraction = time_data.ntp_fraction;
+  }
   if (rtp_receiver_statistics) {
     report_block.remote_ssrc = 0;            // Not needed to set send side.
     report_block.media_ssrc = remote_ssrc_;  // SSRC of the RTP packet sender.
     report_block.fraction_lost = rtp_receiver_statistics->fraction_lost;
     report_block.cumulative_lost = rtp_receiver_statistics->cumulative_lost;
     report_block.extended_high_sequence_number =
         rtp_receiver_statistics->extended_high_sequence_number;
     report_block.jitter = rtp_receiver_statistics->jitter;
     report_block.last_sr = last_report_truncated_ntp_;
     if (!time_last_report_received_.is_null()) {
       uint32_t delay_seconds = 0;
       uint32_t delay_fraction = 0;
       base::TimeDelta delta = time_data.timestamp - time_last_report_received_;
       ConvertTimeToFractions(delta.InMicroseconds(), &delay_seconds,
                              &delay_fraction);
       report_block.delay_since_last_sr =
           ConvertToNtpDiff(delay_seconds, delay_fraction);
     } else {
       report_block.delay_since_last_sr = 0;
     }
   }
   RtcpBuilder rtcp_builder(local_ssrc_);
   packet_sender_->SendRtcpPacket(
-      local_ssrc_, rtcp_builder.BuildRtcpFromReceiver(
-                       rtp_receiver_statistics ? &report_block : NULL, &rrtr,
-                       cast_message, rtcp_events, target_delay));
+      local_ssrc_,
+      rtcp_builder.BuildRtcpFromReceiver(
+          rtp_receiver_statistics ? &report_block : nullptr,
+          (cast_message && cast_message->picture_loss_indicator) ? nullptr

[miu, 2016/02/26 23:36:06]

Separate argument for PLI here too.

Also, it seems like you can send the RRTR along with the PLI, if |cast_message|
was not null.  See comments in rtcp_builder.cc.

[xjz, 2016/02/27 05:53:32]

Done.

+                                                                 : &rrtr,
+          cast_message, rtcp_events, target_delay));
 }
 
 void ReceiverRtcpSession::OnReceivedLipSyncInfo(RtpTimeTicks rtp_timestamp,
                                                 uint32_t ntp_seconds,
                                                 uint32_t ntp_fraction) {
   if (ntp_seconds == 0) {
     NOTREACHED();
     return;
   }
   lip_sync_rtp_timestamp_ = rtp_timestamp;
@@ skipping 17 matching lines @@
   DCHECK((clock_->NowTicks() - local_reference_time) <
          base::TimeDelta::FromMinutes(1));
 
   *rtp_timestamp = lip_sync_rtp_timestamp_;
   *reference_time = local_reference_time;
   return true;
 }
 
 }  // namespace cast
 }  // namespace media