Padding is now used to check for continuity in the packet sequence.

webrtc/modules/video_coding/packet_buffer.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 48 matching lines @@
     index = seq_num % size_;
 
     // Packet buffer is still full.
     if (sequence_buffer_[index].used)
       return false;
   }
 
   if (AheadOf(seq_num, last_seq_num_))
     last_seq_num_ = seq_num;
 
+  // If this is a padding or FEC packet, don't insert it.
+  if (packet.sizeBytes == 0) {
+    reference_finder_.PaddingReceived(packet.seqNum);
+    return true;
+  }
+
   sequence_buffer_[index].frame_begin = packet.isFirstPacket;
   sequence_buffer_[index].frame_end = packet.markerBit;
   sequence_buffer_[index].seq_num = packet.seqNum;
   sequence_buffer_[index].continuous = false;
   sequence_buffer_[index].frame_created = false;
   sequence_buffer_[index].used = true;
   data_buffer_[index] = packet;
 
   FindFrames(seq_num);
   return true;
@@ skipping 145 matching lines @@
 void PacketBuffer::Clear() {
   rtc::CritScope lock(&crit_);
   for (size_t i = 0; i < size_; ++i)
     sequence_buffer_[i].used = false;
 
   first_packet_received_ = false;
 }
 
 }  // namespace video_coding
 }  // namespace webrtc