Use picture id to check continuity between frames.

webrtc/modules/video_coding/rtp_frame_reference_finder.h

 /*
  *  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 30 matching lines @@
   static const int kMaxStashedFrames = 10;
   static const int kMaxNotYetReceivedFrames = 20;
   static const int kMaxGofSaved = 15;
 
   rtc::CriticalSection crit_;
 
   // Retry finding references for all frames that previously didn't have
   // all information needed.
   void RetryStashedFrames() EXCLUSIVE_LOCKS_REQUIRED(crit_);
 
-  // Find references for generic frames.
-  void ManageFrameGeneric(std::unique_ptr<RtpFrameObject> frame)
-      EXCLUSIVE_LOCKS_REQUIRED(crit_);
+  // Find references for generic frames. If |picture_id| is unspecified
+  // then packet sequence numbers will be used to determine the references
+  // of the frames.
+  void ManageFrameGeneric(std::unique_ptr<RtpFrameObject> frame,
+                          int picture_id) EXCLUSIVE_LOCKS_REQUIRED(crit_);
 
   // Find references for Vp8 frames
   void ManageFrameVp8(std::unique_ptr<RtpFrameObject> frame)
       EXCLUSIVE_LOCKS_REQUIRED(crit_);
 
   // Updates all necessary state used to determine frame references
   // for Vp8 and then calls the |frame_callback| callback with the
   // completed frame.
   void CompletedFrameVp8(std::unique_ptr<RtpFrameObject> frame)
       EXCLUSIVE_LOCKS_REQUIRED(crit_);
@@ skipping 79 matching lines @@
              kMaxTemporalLayers>
       missing_frames_for_layer_ GUARDED_BY(crit_);
 
   OnCompleteFrameCallback* frame_callback_;
 };
 
 }  // namespace video_coding
 }  // namespace webrtc
 
 #endif  // WEBRTC_MODULES_VIDEO_CODING_RTP_FRAME_REFERENCE_FINDER_H_