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

webrtc/modules/video_coding/frame_buffer2.cc

 /*
  *  Copyright (c) 2016 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 41 matching lines @@
       num_frames_buffered_(0),
       stopped_(false),
       protection_mode_(kProtectionNack),
       stats_callback_(stats_callback),
       last_log_non_decoded_ms_(-kLogNonDecodedIntervalMs) {}
 
 FrameBuffer::~FrameBuffer() {}
 
 FrameBuffer::ReturnReason FrameBuffer::NextFrame(
     int64_t max_wait_time_ms,
-    std::unique_ptr<FrameObject>* frame_out) {
+    std::unique_ptr<FrameObject>* frame_out,
+    bool keyframe_required) {
   TRACE_EVENT0("webrtc", "FrameBuffer::NextFrame");
   int64_t latest_return_time_ms =
       clock_->TimeInMilliseconds() + max_wait_time_ms;
   int64_t wait_ms = max_wait_time_ms;
   int64_t now_ms = 0;
 
   do {
     now_ms = clock_->TimeInMilliseconds();
     {
       rtc::CritScope lock(&crit_);
@@ skipping 25 matching lines @@
         ++continuous_end_it;
 
       for (; frame_it != continuous_end_it && frame_it != frames_.end();
            ++frame_it) {
         if (!frame_it->second.continuous ||
             frame_it->second.num_missing_decodable > 0) {
           continue;
         }
 
         FrameObject* frame = frame_it->second.frame.get();
+
+        if (keyframe_required && !frame->is_keyframe())
+          continue;
+
         next_frame_it_ = frame_it;
         if (frame->RenderTime() == -1)
           frame->SetRenderTime(timing_->RenderTimeMs(frame->timestamp, now_ms));
         wait_ms = timing_->MaxWaitingTime(frame->RenderTime(), now_ms);
 
         // This will cause the frame buffer to prefer high framerate rather
         // than high resolution in the case of the decoder not decoding fast
         // enough and the stream has multiple spatial and temporal layers.
         if (wait_ms == 0)
           continue;
@@ skipping 154 matching lines @@
     timing_->set_min_playout_delay(playout_delay.min_ms);
 
   if (playout_delay.max_ms >= 0)
     timing_->set_max_playout_delay(playout_delay.max_ms);
 }
 
 int FrameBuffer::InsertFrame(std::unique_ptr<FrameObject> frame) {
   TRACE_EVENT0("webrtc", "FrameBuffer::InsertFrame");
   RTC_DCHECK(frame);
   if (stats_callback_)
-    stats_callback_->OnCompleteFrame(frame->num_references == 0, frame->size());
+    stats_callback_->OnCompleteFrame(frame->is_keyframe(), frame->size());
   FrameKey key(frame->picture_id, frame->spatial_layer);
 
   rtc::CritScope lock(&crit_);
 
   int last_continuous_picture_id =
       last_continuous_frame_it_ == frames_.end()
           ? -1
           : last_continuous_frame_it_->first.picture_id;
 
   if (!ValidReferences(*frame)) {
     LOG(LS_WARNING) << "Frame with (picture_id:spatial_id) (" << key.picture_id
                     << ":" << static_cast<int>(key.spatial_layer)
                     << ") has invalid frame references, dropping frame.";
     return last_continuous_picture_id;
   }
 
   if (num_frames_buffered_ >= kMaxFramesBuffered) {
     LOG(LS_WARNING) << "Frame with (picture_id:spatial_id) (" << key.picture_id
                     << ":" << static_cast<int>(key.spatial_layer)
                     << ") could not be inserted due to the frame "
                     << "buffer being full, dropping frame.";
     return last_continuous_picture_id;
   }
 
   if (last_decoded_frame_it_ != frames_.end() &&
       key <= last_decoded_frame_it_->first) {
     if (AheadOf(frame->timestamp, last_decoded_frame_timestamp_) &&
-        frame->num_references == 0) {
+        frame->is_keyframe()) {
       // If this frame has a newer timestamp but an earlier picture id then we
       // assume there has been a jump in the picture id due to some encoder
       // reconfiguration or some other reason. Even though this is not according
       // to spec we can still continue to decode from this frame if it is a
       // keyframe.
       LOG(LS_WARNING) << "A jump in picture id was detected, clearing buffer.";
       ClearFramesAndHistory();
       last_continuous_picture_id = -1;
     } else {
       LOG(LS_WARNING) << "Frame with (picture_id:spatial_id) ("
@@ skipping 240 matching lines @@
   frames_.clear();
   last_decoded_frame_it_ = frames_.end();
   last_continuous_frame_it_ = frames_.end();
   next_frame_it_ = frames_.end();
   num_frames_history_ = 0;
   num_frames_buffered_ = 0;
 }
 
 }  // namespace video_coding
 }  // namespace webrtc