Add QP sum stats for received streams.

webrtc/video/receive_statistics_proxy.cc

 /*
  *  Copyright (c) 2013 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 377 matching lines @@
   } else {
     auto it = rtx_stats_.find(ssrc);
     if (it != rtx_stats_.end()) {
       it->second = counters;
     } else {
       RTC_NOTREACHED() << "Unexpected stream ssrc: " << ssrc;
     }
   }
 }
 
-void ReceiveStatisticsProxy::OnDecodedFrame() {
+void ReceiveStatisticsProxy::OnDecodedFrame(int qp) {
   uint64_t now = clock_->TimeInMilliseconds();
 
   rtc::CritScope lock(&crit_);
   ++stats_.frames_decoded;
+  if (qp != -1) {
+    if (!stats_.qp_sum)
+      stats_.qp_sum = rtc::Optional<uint64_t>(0);
+    *stats_.qp_sum += qp;
+  }

[hbos, 2017/01/25 11:31:12]

Either all frames or no frames should have qp values. If only some of them have
qp values then qp sum will not align with the framesDecoded values and that is a
bug. Should we DCHECK that?

++stats_.frames_decoded;
if (qp) {
  if (!stats_.qp_sum) {
    RTC_DCHECK_EQ(stats_.frames_decoded, 1);
    stats_.qp_sum = rtc::Optional<uint64_t>(0);
  }
  *stats_.qp_sum += *qp;
} else {
  RTC_DCHECK(!stats_.qp_sum);
}

[sakal, 2017/01/25 12:39:34]

Done.

   decode_fps_estimator_.Update(1, now);
   stats_.decode_frame_rate = decode_fps_estimator_.Rate(now).value_or(0);
 }
 
 void ReceiveStatisticsProxy::OnRenderedFrame(const VideoFrame& frame) {
   int width = frame.width();
   int height = frame.height();
   RTC_DCHECK_GT(width, 0);
   RTC_DCHECK_GT(height, 0);
   uint64_t now = clock_->TimeInMilliseconds();
@@ skipping 70 matching lines @@
     return -1;
   return static_cast<int>(sum / num_samples);
 }
 
 void ReceiveStatisticsProxy::SampleCounter::Reset() {
   num_samples = 0;
   sum = 0;
 }
 
 }  // namespace webrtc