Report max interframe delay over window insdead of interframe delay sum

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 25 matching lines @@
 // Low means low enough to be bad, high means high enough to be good
 const int kLowFpsThreshold = 12;
 const int kHighFpsThreshold = 14;
 // For qp and fps variance:
 // Low means low enough to be good, high means high enough to be bad
 const int kLowQpThresholdVp8 = 60;
 const int kHighQpThresholdVp8 = 70;
 const int kLowVarianceThreshold = 1;
 const int kHighVarianceThreshold = 2;
 
+// Some metrics are reported as a maximum over this period.
+const int kMovingMaxWindowMs = 5000;

[sprang_webrtc, 2017/08/18 09:06:49]

I think this interval needs to be longer. At least 10s.
Also, document it in the api.

[ilnik, 2017/08/18 11:43:01]

Done.

+
 // How large window we use to calculate the framerate/bitrate.
 const int kRateStatisticsWindowSizeMs = 1000;
 }  // namespace
 
 ReceiveStatisticsProxy::ReceiveStatisticsProxy(
     const VideoReceiveStream::Config* config,
     Clock* clock)
     : clock_(clock),
       config_(*config),
       start_ms_(clock->TimeInMilliseconds()),
@@ skipping 15 matching lines @@
       // 1000ms window, scale 1000 for ms to s.
       decode_fps_estimator_(1000, 1000),
       renders_fps_estimator_(1000, 1000),
       render_fps_tracker_(100, 10u),
       render_pixel_tracker_(100, 10u),
       total_byte_tracker_(100, 10u),  // bucket_interval_ms, bucket_count
       e2e_delay_max_ms_video_(-1),
       e2e_delay_max_ms_screenshare_(-1),
       interframe_delay_max_ms_video_(-1),
       interframe_delay_max_ms_screenshare_(-1),
+      interframe_delay_max_moving_(kMovingMaxWindowMs),
       freq_offset_counter_(clock, nullptr, kFreqOffsetProcessIntervalMs),
       first_report_block_time_ms_(-1),
       avg_rtt_ms_(0),
       last_content_type_(VideoContentType::UNSPECIFIED) {
   stats_.ssrc = config_.rtp.remote_ssrc;
   // TODO(brandtr): Replace |rtx_stats_| with a single instance of
   // StreamDataCounters.
   if (config_.rtp.rtx_ssrc) {
     rtx_stats_[config_.rtp.rtx_ssrc] = StreamDataCounters();
   }
@@ skipping 296 matching lines @@
 VideoReceiveStream::Stats ReceiveStatisticsProxy::GetStats() const {
   rtc::CritScope lock(&crit_);
   // Get current frame rates here, as only updating them on new frames prevents
   // us from ever correctly displaying frame rate of 0.
   int64_t now_ms = clock_->TimeInMilliseconds();
   UpdateFramerate(now_ms);
   stats_.render_frame_rate = renders_fps_estimator_.Rate(now_ms).value_or(0);
   stats_.decode_frame_rate = decode_fps_estimator_.Rate(now_ms).value_or(0);
   stats_.total_bitrate_bps =
       static_cast<int>(total_byte_tracker_.ComputeRate() * 8);
+  stats_.interframe_delay_max_ms =
+      interframe_delay_max_moving_.MovingMax(now_ms).value_or(0);
   return stats_;
 }
 
 rtc::Optional<TimingFrameInfo>
 ReceiveStatisticsProxy::GetAndResetTimingFrameInfo() {
   rtc::CritScope lock(&crit_);
   rtc::Optional<TimingFrameInfo> info = timing_frame_info_;
   // Reset reported value to empty, so it will be always
   // overwritten in |OnTimingFrameInfoUpdated|, thus allowing to store new
   // value instead of reported one.
@@ skipping 130 matching lines @@
   } else if (stats_.qp_sum) {
     LOG(LS_WARNING)
         << "QP sum was already set and no QP was given for a frame.";
     stats_.qp_sum = rtc::Optional<uint64_t>();
   }
   last_content_type_ = content_type;
   decode_fps_estimator_.Update(1, now);
   if (last_decoded_frame_time_ms_) {
     int64_t interframe_delay_ms = now - *last_decoded_frame_time_ms_;
     RTC_DCHECK_GE(interframe_delay_ms, 0);
-    stats_.interframe_delay_sum_ms += interframe_delay_ms;
+    interframe_delay_max_moving_.Add(interframe_delay_ms, now);
     if (last_content_type_ == VideoContentType::SCREENSHARE) {
       interframe_delay_counter_screenshare_.Add(interframe_delay_ms);
       if (interframe_delay_max_ms_screenshare_ < interframe_delay_ms) {
         interframe_delay_max_ms_screenshare_ = interframe_delay_ms;
       }
     } else {
       interframe_delay_counter_video_.Add(interframe_delay_ms);
       if (interframe_delay_max_ms_video_ < interframe_delay_ms) {
         interframe_delay_max_ms_video_ = interframe_delay_ms;
       }
@@ skipping 100 matching lines @@
   if (num_samples < min_required_samples || num_samples == 0)
     return -1;
   return static_cast<int>(sum / num_samples);
 }
 
 void ReceiveStatisticsProxy::SampleCounter::Reset() {
   num_samples = 0;
   sum = 0;
 }
 
+void ReceiveStatisticsProxy::MovingMaxCounter::Add(int sample,
+                                                   int64_t time_ms) {
+  int64_t window_begin_ms = time_ms - window_length_ms_;
+  // Throw out obsolete samples.
+  while (!samples_.empty() && samples_.front().first < window_begin_ms) {
+    samples_.pop_front();
+  }
+  // Remove samples what will never be maximum in any window: newly added sample
+  // will always be in all windows the previous samples are. Thus, smaller
+  // samples could be removed. This will maintain the invariant - deque contains
+  // non-increasing sequence of values.
+  while (!samples_.empty() && samples_.back().second < sample) {
+    samples_.pop_back();
+  }
+  samples_.push_back(std::make_pair(time_ms, sample));

[sprang_webrtc, 2017/08/18 09:06:49]

emplace_back even?

[ilnik, 2017/08/18 11:43:01]

Done.

+}
+
+rtc::Optional<int> ReceiveStatisticsProxy::MovingMaxCounter::MovingMax(
+    int64_t time_ms) const {
+  rtc::Optional<int> res;
+  if (samples_.empty()) {
+      return res;
+  }
+  int64_t window_begin_ms = time_ms - window_length_ms_;
+  auto it = samples_.begin();
+  while (it != samples_.end() && it->first < window_begin_ms) {
+    ++it;
+  }
+  if (it != samples_.end()) {
+    res.emplace(it->second);
+  }
+  return res;
+}
+
+void ReceiveStatisticsProxy::MovingMaxCounter::Reset() {
+  samples_.clear();
+}
+
+
 void ReceiveStatisticsProxy::OnRttUpdate(int64_t avg_rtt_ms,
                                          int64_t max_rtt_ms) {
   rtc::CritScope lock(&crit_);
   avg_rtt_ms_ = avg_rtt_ms;
 }
 
 }  // namespace webrtc