Advance picture id of keyframe if the stream has been continuous without a new keyframe for a while.

webrtc/modules/video_coding/rtp_frame_reference_finder_unittest.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 282 matching lines @@
   reference_finder_->PaddingReceived(sn + 4);
   InsertGeneric(sn + 2, sn + 3, false);
   InsertGeneric(sn + 5, sn + 5, true);
   reference_finder_->PaddingReceived(sn + 6);
   reference_finder_->PaddingReceived(sn + 9);
   InsertGeneric(sn + 7, sn + 8, false);
 
   EXPECT_EQ(4UL, frames_from_callback_.size());
 }
 
+TEST_F(TestRtpFrameReferenceFinder, AdvanceSavedKeyframe) {
+  uint16_t sn = Rand();

[terelius, 2017/02/20 13:19:48]

With a random sequence number you have no way of knowing if or when the sequence
number wraps, right?

[philipel, 2017/02/20 13:26:42]

That is true, but the problem only occurs when the sequence number of the last
packet of a frame is further ahead than <keyframe sequence number + 2^15>. If
the actual sequence number has wrapped or not does not matter in this case.

+
+  InsertGeneric(sn, sn, true);
+  InsertGeneric(sn + 1, sn + 1, true);
+  InsertGeneric(sn + 2, sn + 10000, false);
+  InsertGeneric(sn + 10001, sn + 20000, false);
+  InsertGeneric(sn + 20001, sn + 30000, false);
+  InsertGeneric(sn + 30001, sn + 40000, false);
+
+  EXPECT_EQ(6UL, frames_from_callback_.size());
+}
+
 TEST_F(TestRtpFrameReferenceFinder, ClearTo) {
   uint16_t sn = Rand();
 
   InsertGeneric(sn, sn + 1, true);
   InsertGeneric(sn + 4, sn + 5, false);  // stashed
   EXPECT_EQ(1UL, frames_from_callback_.size());
 
   InsertGeneric(sn + 6, sn + 7, true);  // keyframe
   EXPECT_EQ(2UL, frames_from_callback_.size());
   reference_finder_->ClearTo(sn + 7);
@@ skipping 1165 matching lines @@
     reference_finder_->ManageFrame(std::move(frame));
   }
 
   ASSERT_EQ(2UL, frames_from_callback_.size());
   CheckReferencesVp9(1, 0);
   CheckReferencesVp9(129, 0);
 }
 
 }  // namespace video_coding
 }  // namespace webrtc