Add logging statements to places where the frame might be dropped in WebRTC pipeline.

webrtc/common_video/video_render_frames.cc

 /*
  *  Copyright (c) 2012 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.
  */
 
 #include "webrtc/common_video/video_render_frames.h"
 
 #include <assert.h>
 
+#include "webrtc/base/logging.h"
 #include "webrtc/base/timeutils.h"
 #include "webrtc/modules/include/module_common_types.h"
 #include "webrtc/system_wrappers/include/trace.h"
 
 namespace webrtc {
 namespace {
 
 const uint32_t kEventMaxWaitTimeMs = 200;
 const uint32_t kMinRenderDelayMs = 10;
 const uint32_t kMaxRenderDelayMs = 500;
+const size_t kMaxIncomingFramesBeforeLogged = 100;
 
 uint32_t EnsureValidRenderDelay(uint32_t render_delay) {
   return (render_delay < kMinRenderDelayMs || render_delay > kMaxRenderDelayMs)
              ? kMinRenderDelayMs
              : render_delay;
 }
 }  // namespace
 
 VideoRenderFrames::VideoRenderFrames(uint32_t render_delay_ms)
     : render_delay_ms_(EnsureValidRenderDelay(render_delay_ms)) {}
@@ skipping 15 matching lines @@
   }
 
   if (new_frame.render_time_ms() > time_now + KFutureRenderTimestampMS) {
     WEBRTC_TRACE(kTraceWarning, kTraceVideoRenderer, -1,
                  "%s: frame too long into the future, timestamp=%u.",
                  __FUNCTION__, new_frame.timestamp());
     return -1;
   }
 
   incoming_frames_.push_back(new_frame);
+  if (incoming_frames_.size() > kMaxIncomingFramesBeforeLogged)
+    LOG(LS_WARNING) << "Stored incoming frames: " << incoming_frames_.size();
   return static_cast<int32_t>(incoming_frames_.size());
 }
 
 rtc::Optional<VideoFrame> VideoRenderFrames::FrameToRender() {
   rtc::Optional<VideoFrame> render_frame;
   // Get the newest frame that can be released for rendering.
   while (!incoming_frames_.empty() && TimeToNextFrameRelease() <= 0) {
     render_frame = rtc::Optional<VideoFrame>(incoming_frames_.front());
     incoming_frames_.pop_front();
   }
   return render_frame;
 }
 
 uint32_t VideoRenderFrames::TimeToNextFrameRelease() {
   if (incoming_frames_.empty()) {
     return kEventMaxWaitTimeMs;
   }
   const int64_t time_to_release = incoming_frames_.front().render_time_ms() -
                                   render_delay_ms_ -
                                   rtc::TimeMillis();
   return time_to_release < 0 ? 0u : static_cast<uint32_t>(time_to_release);
 }
 
 }  // namespace webrtc