Drop VP8 frames in case of duplicates in RtpFrameReferenceFinder.

webrtc/modules/video_coding/rtp_frame_reference_finder.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 316 matching lines @@
     // frame then we have to wait for that frame to be completed first.
     auto not_received_frame_it =
         not_yet_received_frames_.upper_bound(layer_info_it->second[layer]);
     if (not_received_frame_it != not_yet_received_frames_.end() &&
         AheadOf<uint16_t, kPicIdLength>(frame->picture_id,
                                         *not_received_frame_it)) {
       stashed_frames_.push_back(std::move(frame));
       return;
     }
 
-    RTC_DCHECK((AheadOf<uint16_t, kPicIdLength>(frame->picture_id,
-                                               layer_info_it->second[layer])));
+    if (!(AheadOf<uint16_t, kPicIdLength>(frame->picture_id,
+                                          layer_info_it->second[layer]))) {
+      LOG(LS_WARNING) << "Frame with picture id " << frame->picture_id
+                      << " and packet range [" << frame->first_seq_num() << ", "
+                      << frame->last_seq_num() << "] already received, "
+                      << " dropping frame.";
+      return;
+    }

[stefan-webrtc, 2017/03/06 15:49:26]

Seems like we can get a lot of these logs on a network with some packet loss,
especially if we have FEC. Should we throttle the logs a bit, or do you think it
isn't an issue?

[philipel, 2017/03/07 10:47:11]

I don't think it will be an issue since we need to decode a frame and then
receive it again for it to happen.

+
     ++frame->num_references;
     frame->references[layer] = layer_info_it->second[layer];
   }
 
   CompletedFrameVp8(std::move(frame));
 }
 
 void RtpFrameReferenceFinder::CompletedFrameVp8(
     std::unique_ptr<RtpFrameObject> frame) {
   rtc::Optional<RTPVideoTypeHeader> rtp_codec_header = frame->GetCodecHeader();
@@ skipping 392 matching lines @@
     if (!gof_info_.empty() &&
         AheadOf<uint8_t>(gof_info_.begin()->first, fixed_tl0)) {
       return true;
     }
   }
   return false;
 }
 
 }  // namespace video_coding
 }  // namespace webrtc