commit bc5a40870c6d83642523d27c660f75896ac5d6c3
author philipel <philipel@webrtc.org> Wed Dec 06 09:41:08 2017
committer Commit Bot <commit-bot@chromium.org> Wed Dec 06 12:15:42 2017
tree 3b86a06ee0e11a806b8de16974296eab95c825eb
parent a129ed60e07561ebdd527e3d3ce47c7ee11eb846

Fix off-by-one error when removing information about missing packet in PacketBuffer.

In the ClearTo function we risked removing one packet too many from the set of
|missing_packets_|, and in the case of H264 this would cause us to create incomplete
delta frames. This is turn disrupt the stream and a keyframe request has to be made.

Bug: webrtc:8536
Change-Id: Ie7ccd5f1631a4cf3bd463878d5b0fe746744ec23
Reviewed-on: https://webrtc-review.googlesource.com/30141
Commit-Queue: Philip Eliasson <philipel@webrtc.org>
Reviewed-by: Rasmus Brandt <brandtr@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#21119}

modules/video_coding/packet_buffer.cc

diff --git a/modules/video_coding/packet_buffer.cc b/modules/video_coding/packet_buffer.cc
index 9b3d93e..741c11e 100644
--- a/modules/video_coding/packet_buffer.cc
+++ b/modules/video_coding/packet_buffer.cc
@@ -162,8 +162,11 @@
   first_seq_num_ = seq_num;
 
   is_cleared_to_first_seq_num_ = true;
-  missing_packets_.erase(missing_packets_.begin(),
-                         missing_packets_.upper_bound(seq_num));
+  auto clear_to_it = missing_packets_.upper_bound(seq_num);
+  if (clear_to_it != missing_packets_.begin()) {
+    --clear_to_it;
+    missing_packets_.erase(missing_packets_.begin(), clear_to_it);
+  }
 }
 
 void PacketBuffer::Clear() {

modules/video_coding/video_packet_buffer_unittest.cc

diff --git a/modules/video_coding/video_packet_buffer_unittest.cc b/modules/video_coding/video_packet_buffer_unittest.cc
index f8b3dc6..8936493 100644
--- a/modules/video_coding/video_packet_buffer_unittest.cc
+++ b/modules/video_coding/video_packet_buffer_unittest.cc
@@ -489,6 +489,16 @@
                         TestPacketBufferH264Parameterized,
                         ::testing::Values(false, true));
 
+TEST_P(TestPacketBufferH264Parameterized, DontRemoveMissingPacketOnClearTo) {
+  EXPECT_TRUE(InsertH264(0, kKeyFrame, kFirst, kLast, 0));
+  EXPECT_TRUE(InsertH264(2, kDeltaFrame, kFirst, kNotLast, 2));
+  packet_buffer_->ClearTo(0);
+  EXPECT_TRUE(InsertH264(3, kDeltaFrame, kNotFirst, kLast, 2));
+
+  ASSERT_EQ(1UL, frames_from_callback_.size());
+  CheckFrame(0);
+}
+
 TEST_P(TestPacketBufferH264Parameterized, GetBitstreamOneFrameFullBuffer) {
   uint8_t* data_arr[kStartSize];
   uint8_t expected[kStartSize];