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Use timestamp instead of seq_num to distinguish between packets.

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In the case a frame_object is kept for some time before it is deleted,
it may happend that a new frame is received with overlapping sequence
numbers. If the old frame_object is removed while receiving the new
frame there used to be a crash.

Bug: webrtc:9629
Change-Id: I270a8caa2b58b73c000542aa504c0ebe277d49c4
Reviewed-on: https://webrtc-review.googlesource.com/102683
Reviewed-by: Philip Eliasson <philipel@webrtc.org>
Commit-Queue: Johannes Kron <kron@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#24914}
This commit is contained in:
Johannes Kron
2018-10-01 14:53:01 +02:00
committed by Commit Bot
parent 147013a60f
commit 957c62e0d6
2 changed files with 51 additions and 2 deletions
Download Patch File Download Diff File Expand all files Collapse all files

12
modules/video_coding/packet_buffer.cc
View File

@ -398,8 +398,12 @@ void PacketBuffer::ReturnFrame(RtpFrameObject* frame) {
size_t index = frame->first_seq_num() % size_;
size_t end = (frame->last_seq_num() + 1) % size_;
uint16_t seq_num = frame->first_seq_num();
uint32_t timestamp = frame->Timestamp();
while (index != end) {
if (sequence_buffer_[index].seq_num == seq_num) {
// Check both seq_num and timestamp to handle the case when seq_num wraps
// around too quickly for high packet rates.
if (sequence_buffer_[index].seq_num == seq_num &&
data_buffer_[index].timestamp == timestamp) {
delete[] data_buffer_[index].dataPtr;
data_buffer_[index].dataPtr = nullptr;
sequence_buffer_[index].used = false;
@ -417,11 +421,15 @@ bool PacketBuffer::GetBitstream(const RtpFrameObject& frame,
size_t index = frame.first_seq_num() % size_;
size_t end = (frame.last_seq_num() + 1) % size_;
uint16_t seq_num = frame.first_seq_num();
uint32_t timestamp = frame.Timestamp();
uint8_t* destination_end = destination + frame.size();
do {
// Check both seq_num and timestamp to handle the case when seq_num wraps
// around too quickly for high packet rates.
if (!sequence_buffer_[index].used ||
sequence_buffer_[index].seq_num != seq_num) {
sequence_buffer_[index].seq_num != seq_num ||
data_buffer_[index].timestamp != timestamp) {
return false;
}

41
modules/video_coding/video_packet_buffer_unittest.cc
View File

@ -82,6 +82,14 @@ class TestPacketBuffer : public ::testing::Test,
<< ".";
}
void DeleteFrame(uint16_t first_seq_num) {
auto frame_it = frames_from_callback_.find(first_seq_num);
ASSERT_FALSE(frame_it == frames_from_callback_.end())
<< "Could not find frame with first sequence number " << first_seq_num
<< ".";
frames_from_callback_.erase(frame_it);
}
static constexpr int kStartSize = 16;
static constexpr int kMaxSize = 64;
@ -494,6 +502,39 @@ TEST_F(TestPacketBuffer, GetBitstreamOneFrameFullBuffer) {
EXPECT_EQ(memcmp(result, expected, kStartSize), 0);
}
TEST_F(TestPacketBuffer, InsertPacketAfterOldFrameObjectIsRemoved) {
uint16_t kFirstSeqNum = 0;
uint32_t kTimestampDelta = 100;
uint32_t timestamp = 10000;
uint16_t seq_num = kFirstSeqNum;
// Loop until seq_num wraps around.
SeqNumUnwrapper<uint16_t> unwrapper(0);
while (unwrapper.Unwrap(seq_num) < std::numeric_limits<uint16_t>::max()) {
Insert(seq_num++, kKeyFrame, kFirst, kNotLast, 0, nullptr, timestamp);
for (int i = 0; i < 5; ++i) {
Insert(seq_num++, kKeyFrame, kNotFirst, kNotLast, 0, nullptr, timestamp);
}
Insert(seq_num++, kKeyFrame, kNotFirst, kLast, 0, nullptr, timestamp);
timestamp += kTimestampDelta;
}
size_t number_of_frames = frames_from_callback_.size();
// Delete old frame object while receiving frame with overlapping sequence
// numbers.
Insert(seq_num++, kKeyFrame, kFirst, kNotLast, 0, nullptr, timestamp);
for (int i = 0; i < 5; ++i) {
Insert(seq_num++, kKeyFrame, kNotFirst, kNotLast, 0, nullptr, timestamp);
}
// Delete FrameObject connected to packets that have already been cleared.
DeleteFrame(kFirstSeqNum);
Insert(seq_num++, kKeyFrame, kNotFirst, kLast, 0, nullptr, timestamp);
// Regardless of the initial size, the number of frames should be constant
// after removing and then adding a new frame object.
EXPECT_EQ(number_of_frames, frames_from_callback_.size());
}
// If |sps_pps_idr_is_keyframe| is true, we require keyframes to contain
// SPS/PPS/IDR and the keyframes we create as part of the test do contain
// SPS/PPS/IDR. If |sps_pps_idr_is_keyframe| is false, we only require and