Reland of quest keyframes more frequently on stream start/decoding error.

webrtc/video/video_receive_stream.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 473 matching lines @@
 }
 
 void VideoReceiveStream::DecodeThreadFunction(void* ptr) {
   while (static_cast<VideoReceiveStream*>(ptr)->Decode()) {
   }
 }
 
 bool VideoReceiveStream::Decode() {
   TRACE_EVENT0("webrtc", "VideoReceiveStream::Decode");
   static const int kMaxWaitForFrameMs = 3000;
+  static const int kMaxWaitForKeyFrameMs = 200;
+
+  int wait_ms = keyframe_required_ ? kMaxWaitForKeyFrameMs : kMaxWaitForFrameMs;
   std::unique_ptr<video_coding::FrameObject> frame;
+  // TODO(philipel): Call NextFrame with |keyframe_required| argument when
+  //                 downstream project has been fixed.
   video_coding::FrameBuffer::ReturnReason res =
-      frame_buffer_->NextFrame(kMaxWaitForFrameMs, &frame);
+      frame_buffer_->NextFrame(wait_ms, &frame);
 
   if (res == video_coding::FrameBuffer::ReturnReason::kStopped) {
     video_receiver_.DecodingStopped();
     return false;
   }
 
   if (frame) {
     RTC_DCHECK_EQ(res, video_coding::FrameBuffer::ReturnReason::kFrameFound);
-    if (video_receiver_.Decode(frame.get()) == VCM_OK)
+    if (video_receiver_.Decode(frame.get()) == VCM_OK) {
+      keyframe_required_ = false;
       rtp_video_stream_receiver_.FrameDecoded(frame->picture_id);
+    } else if (keyframe_required_ == false) {

[stefan-webrtc, 2017/08/11 09:27:59]

!keyframe_required_

+      keyframe_required_ = true;
+      // TODO(philipel): Remove this keyframe request when downstream project
+      //                 has been fixed.
+      RequestKeyFrame();
+    }
   } else {
     RTC_DCHECK_EQ(res, video_coding::FrameBuffer::ReturnReason::kTimeout);
     int64_t now_ms = clock_->TimeInMilliseconds();
     rtc::Optional<int64_t> last_packet_ms =
         rtp_video_stream_receiver_.LastReceivedPacketMs();
     rtc::Optional<int64_t> last_keyframe_packet_ms =
         rtp_video_stream_receiver_.LastReceivedKeyframePacketMs();
 
     // To avoid spamming keyframe requests for a stream that is not active we
     // check if we have received a packet within the last 5 seconds.
     bool stream_is_active = last_packet_ms && now_ms - *last_packet_ms < 5000;
 
-    // If we recently (within |kMaxWaitForFrameMs|) have been receiving packets
-    // belonging to a keyframe then we assume a keyframe is being received right
-    // now.
+    // If we recently have been receiving packets belonging to a keyframe then
+    // we assume a keyframe is currently being received.
     bool receiving_keyframe =
         last_keyframe_packet_ms &&
-        now_ms - *last_keyframe_packet_ms < kMaxWaitForFrameMs;
+        now_ms - *last_keyframe_packet_ms < kMaxWaitForKeyFrameMs;
 
     if (stream_is_active && !receiving_keyframe) {
-      LOG(LS_WARNING) << "No decodable frame in " << kMaxWaitForFrameMs
+      LOG(LS_WARNING) << "No decodable frame in " << wait_ms
                       << " ms, requesting keyframe.";
       RequestKeyFrame();
     }
   }
   return true;
 }
 }  // namespace internal
 }  // namespace webrtc