Track last packet receive times in RtpVideoStreamReceiver instead of the PacketBuffer.

Bug: webrtc:12579
Change-Id: I4adb8c6ada913127b9e65d97ddce0dc71ec6ccee
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/214784
Reviewed-by: Sam Zackrisson <saza@webrtc.org>
Reviewed-by: Erik Språng <sprang@webrtc.org>
Commit-Queue: Philip Eliasson <philipel@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#33713}
This commit is contained in:
philipel
2021-04-12 13:42:03 +02:00
committed by Commit Bot
parent cd83ae2d65
commit ce423ce12d
9 changed files with 125 additions and 180 deletions

View File

@ -30,7 +30,6 @@
#include "rtc_base/checks.h"
#include "rtc_base/logging.h"
#include "rtc_base/numerics/mod_ops.h"
#include "system_wrappers/include/clock.h"
namespace webrtc {
namespace video_coding {
@ -51,11 +50,8 @@ PacketBuffer::Packet::Packet(const RtpPacketReceived& rtp_packet,
rtp_packet.GetExtension<AbsoluteCaptureTimeExtension>(),
receive_time_ms) {}
PacketBuffer::PacketBuffer(Clock* clock,
size_t start_buffer_size,
size_t max_buffer_size)
: clock_(clock),
max_size_(max_buffer_size),
PacketBuffer::PacketBuffer(size_t start_buffer_size, size_t max_buffer_size)
: max_size_(max_buffer_size),
first_seq_num_(0),
first_packet_received_(false),
is_cleared_to_first_seq_num_(false),
@ -114,14 +110,6 @@ PacketBuffer::InsertResult PacketBuffer::InsertPacket(
}
}
int64_t now_ms = clock_->TimeInMilliseconds();
last_received_packet_ms_ = now_ms;
if (packet->video_header.frame_type == VideoFrameType::kVideoFrameKey ||
last_received_keyframe_rtp_timestamp_ == packet->timestamp) {
last_received_keyframe_packet_ms_ = now_ms;
last_received_keyframe_rtp_timestamp_ = packet->timestamp;
}
packet->continuous = false;
buffer_[index] = std::move(packet);
@ -181,18 +169,10 @@ PacketBuffer::InsertResult PacketBuffer::InsertPadding(uint16_t seq_num) {
return result;
}
absl::optional<int64_t> PacketBuffer::LastReceivedPacketMs() const {
MutexLock lock(&mutex_);
return last_received_packet_ms_;
}
absl::optional<int64_t> PacketBuffer::LastReceivedKeyframePacketMs() const {
MutexLock lock(&mutex_);
return last_received_keyframe_packet_ms_;
}
void PacketBuffer::ForceSpsPpsIdrIsH264Keyframe() {
sps_pps_idr_is_h264_keyframe_ = true;
}
void PacketBuffer::ClearInternal() {
for (auto& entry : buffer_) {
entry = nullptr;
@ -200,8 +180,6 @@ void PacketBuffer::ClearInternal() {
first_packet_received_ = false;
is_cleared_to_first_seq_num_ = false;
last_received_packet_ms_.reset();
last_received_keyframe_packet_ms_.reset();
newest_inserted_seq_num_.reset();
missing_packets_.clear();
}

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@ -25,7 +25,6 @@
#include "rtc_base/numerics/sequence_number_util.h"
#include "rtc_base/synchronization/mutex.h"
#include "rtc_base/thread_annotations.h"
#include "system_wrappers/include/clock.h"
namespace webrtc {
namespace video_coding {
@ -76,7 +75,7 @@ class PacketBuffer {
};
// Both |start_buffer_size| and |max_buffer_size| must be a power of 2.
PacketBuffer(Clock* clock, size_t start_buffer_size, size_t max_buffer_size);
PacketBuffer(size_t start_buffer_size, size_t max_buffer_size);
~PacketBuffer();
ABSL_MUST_USE_RESULT InsertResult InsertPacket(std::unique_ptr<Packet> packet)
@ -86,16 +85,9 @@ class PacketBuffer {
void ClearTo(uint16_t seq_num) RTC_LOCKS_EXCLUDED(mutex_);
void Clear() RTC_LOCKS_EXCLUDED(mutex_);
// Timestamp (not RTP timestamp) of the last received packet/keyframe packet.
absl::optional<int64_t> LastReceivedPacketMs() const
RTC_LOCKS_EXCLUDED(mutex_);
absl::optional<int64_t> LastReceivedKeyframePacketMs() const
RTC_LOCKS_EXCLUDED(mutex_);
void ForceSpsPpsIdrIsH264Keyframe();
private:
Clock* const clock_;
// Clears with |mutex_| taken.
void ClearInternal() RTC_EXCLUSIVE_LOCKS_REQUIRED(mutex_);
@ -132,13 +124,6 @@ class PacketBuffer {
// determine continuity between them.
std::vector<std::unique_ptr<Packet>> buffer_ RTC_GUARDED_BY(mutex_);
// Timestamp of the last received packet/keyframe packet.
absl::optional<int64_t> last_received_packet_ms_ RTC_GUARDED_BY(mutex_);
absl::optional<int64_t> last_received_keyframe_packet_ms_
RTC_GUARDED_BY(mutex_);
absl::optional<uint32_t> last_received_keyframe_rtp_timestamp_
RTC_GUARDED_BY(mutex_);
absl::optional<uint16_t> newest_inserted_seq_num_ RTC_GUARDED_BY(mutex_);
std::set<uint16_t, DescendingSeqNumComp<uint16_t>> missing_packets_
RTC_GUARDED_BY(mutex_);

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@ -19,7 +19,6 @@
#include "common_video/h264/h264_common.h"
#include "modules/video_coding/frame_object.h"
#include "rtc_base/random.h"
#include "system_wrappers/include/clock.h"
#include "test/field_trial.h"
#include "test/gmock.h"
#include "test/gtest.h"
@ -100,10 +99,7 @@ void PrintTo(const PacketBufferInsertResult& result, std::ostream* os) {
class PacketBufferTest : public ::testing::Test {
protected:
PacketBufferTest()
: rand_(0x7732213),
clock_(0),
packet_buffer_(&clock_, kStartSize, kMaxSize) {}
PacketBufferTest() : rand_(0x7732213), packet_buffer_(kStartSize, kMaxSize) {}
uint16_t Rand() { return rand_.Rand<uint16_t>(); }
@ -133,7 +129,6 @@ class PacketBufferTest : public ::testing::Test {
}
Random rand_;
SimulatedClock clock_;
PacketBuffer packet_buffer_;
};
@ -616,67 +611,6 @@ TEST_F(PacketBufferTest, ContinuousSeqNumDoubleMarkerBit) {
EXPECT_THAT(Insert(3, kKeyFrame, kNotFirst, kLast).packets, IsEmpty());
}
TEST_F(PacketBufferTest, PacketTimestamps) {
absl::optional<int64_t> packet_ms;
absl::optional<int64_t> packet_keyframe_ms;
packet_ms = packet_buffer_.LastReceivedPacketMs();
packet_keyframe_ms = packet_buffer_.LastReceivedKeyframePacketMs();
EXPECT_FALSE(packet_ms);
EXPECT_FALSE(packet_keyframe_ms);
int64_t keyframe_ms = clock_.TimeInMilliseconds();
Insert(100, kKeyFrame, kFirst, kLast, {}, /*timestamp=*/1000);
packet_ms = packet_buffer_.LastReceivedPacketMs();
packet_keyframe_ms = packet_buffer_.LastReceivedKeyframePacketMs();
EXPECT_TRUE(packet_ms);
EXPECT_TRUE(packet_keyframe_ms);
EXPECT_EQ(keyframe_ms, *packet_ms);
EXPECT_EQ(keyframe_ms, *packet_keyframe_ms);
clock_.AdvanceTimeMilliseconds(100);
int64_t delta_ms = clock_.TimeInMilliseconds();
Insert(101, kDeltaFrame, kFirst, kLast, {}, /*timestamp=*/2000);
packet_ms = packet_buffer_.LastReceivedPacketMs();
packet_keyframe_ms = packet_buffer_.LastReceivedKeyframePacketMs();
EXPECT_TRUE(packet_ms);
EXPECT_TRUE(packet_keyframe_ms);
EXPECT_EQ(delta_ms, *packet_ms);
EXPECT_EQ(keyframe_ms, *packet_keyframe_ms);
packet_buffer_.Clear();
packet_ms = packet_buffer_.LastReceivedPacketMs();
packet_keyframe_ms = packet_buffer_.LastReceivedKeyframePacketMs();
EXPECT_FALSE(packet_ms);
EXPECT_FALSE(packet_keyframe_ms);
}
TEST_F(PacketBufferTest,
LastReceivedKeyFrameReturnsReceiveTimeOfALastReceivedPacketOfAKeyFrame) {
clock_.AdvanceTimeMilliseconds(100);
Insert(/*seq_num=*/100, kKeyFrame, kFirst, kNotLast, {}, /*timestamp=*/1000);
EXPECT_EQ(packet_buffer_.LastReceivedKeyframePacketMs(),
clock_.TimeInMilliseconds());
clock_.AdvanceTimeMilliseconds(100);
Insert(/*seq_num=*/102, kDeltaFrame, kNotFirst, kLast, {},
/*timestamp=*/1000);
EXPECT_EQ(packet_buffer_.LastReceivedKeyframePacketMs(),
clock_.TimeInMilliseconds());
clock_.AdvanceTimeMilliseconds(100);
Insert(/*seq_num=*/101, kDeltaFrame, kNotFirst, kNotLast, {},
/*timestamp=*/1000);
EXPECT_EQ(packet_buffer_.LastReceivedKeyframePacketMs(),
clock_.TimeInMilliseconds());
clock_.AdvanceTimeMilliseconds(100);
Insert(/*seq_num=*/103, kDeltaFrame, kFirst, kNotLast, {},
/*timestamp=*/2000);
EXPECT_EQ(packet_buffer_.LastReceivedKeyframePacketMs(),
clock_.TimeInMilliseconds() - 100);
}
TEST_F(PacketBufferTest, IncomingCodecChange) {
auto packet = std::make_unique<PacketBuffer::Packet>();
packet->video_header.is_first_packet_in_frame = true;

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@ -13,7 +13,6 @@
#include "modules/video_coding/frame_object.h"
#include "modules/video_coding/packet_buffer.h"
#include "system_wrappers/include/clock.h"
#include "test/fuzzers/fuzz_data_helper.h"
namespace webrtc {
@ -24,8 +23,7 @@ void FuzzOneInput(const uint8_t* data, size_t size) {
if (size > 200000) {
return;
}
SimulatedClock clock(0);
video_coding::PacketBuffer packet_buffer(&clock, 8, 1024);
video_coding::PacketBuffer packet_buffer(8, 1024);
test::FuzzDataHelper helper(rtc::ArrayView<const uint8_t>(data, size));
while (helper.BytesLeft()) {

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@ -164,6 +164,7 @@ rtc_source_set("video_legacy") {
"../api:sequence_checker",
"../api/crypto:frame_decryptor_interface",
"../api/task_queue",
"../api/units:timestamp",
"../api/video:encoded_image",
"../api/video:recordable_encoded_frame",
"../api/video:video_frame",

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@ -271,7 +271,7 @@ RtpVideoStreamReceiver::RtpVideoStreamReceiver(
// TODO(bugs.webrtc.org/10336): Let |rtcp_feedback_buffer_| communicate
// directly with |rtp_rtcp_|.
rtcp_feedback_buffer_(this, nack_sender, this),
packet_buffer_(clock_, kPacketBufferStartSize, PacketBufferMaxSize()),
packet_buffer_(kPacketBufferStartSize, PacketBufferMaxSize()),
has_received_frame_(false),
frames_decryptable_(false),
absolute_capture_time_receiver_(clock) {
@ -384,11 +384,11 @@ absl::optional<Syncable::Info> RtpVideoStreamReceiver::GetSyncInfo() const {
}
{
MutexLock lock(&sync_info_lock_);
if (!last_received_rtp_timestamp_ || !last_received_rtp_system_time_ms_) {
if (!last_received_rtp_timestamp_ || !last_received_rtp_system_time_) {
return absl::nullopt;
}
info.latest_received_capture_timestamp = *last_received_rtp_timestamp_;
info.latest_receive_time_ms = *last_received_rtp_system_time_ms_;
info.latest_receive_time_ms = last_received_rtp_system_time_->ms();
}
// Leaves info.current_delay_ms uninitialized.
@ -543,6 +543,12 @@ void RtpVideoStreamReceiver::OnReceivedPayloadData(
ParseGenericDependenciesResult generic_descriptor_state =
ParseGenericDependenciesExtension(rtp_packet, &video_header);
if (!rtp_packet.recovered()) {
UpdatePacketReceiveTimestamps(
rtp_packet, video_header.frame_type == VideoFrameType::kVideoFrameKey);
}
if (generic_descriptor_state == kDropPacket)
return;
@ -671,35 +677,6 @@ void RtpVideoStreamReceiver::OnRtpPacket(const RtpPacketReceived& packet) {
return;
}
if (!packet.recovered()) {
// TODO(nisse): Exclude out-of-order packets?
int64_t now_ms = clock_->TimeInMilliseconds();
{
MutexLock lock(&sync_info_lock_);
last_received_rtp_timestamp_ = packet.Timestamp();
last_received_rtp_system_time_ms_ = now_ms;
}
// Periodically log the RTP header of incoming packets.
if (now_ms - last_packet_log_ms_ > kPacketLogIntervalMs) {
rtc::StringBuilder ss;
ss << "Packet received on SSRC: " << packet.Ssrc()
<< " with payload type: " << static_cast<int>(packet.PayloadType())
<< ", timestamp: " << packet.Timestamp()
<< ", sequence number: " << packet.SequenceNumber()
<< ", arrival time: " << packet.arrival_time_ms();
int32_t time_offset;
if (packet.GetExtension<TransmissionOffset>(&time_offset)) {
ss << ", toffset: " << time_offset;
}
uint32_t send_time;
if (packet.GetExtension<AbsoluteSendTime>(&send_time)) {
ss << ", abs send time: " << send_time;
}
RTC_LOG(LS_INFO) << ss.str();
last_packet_log_ms_ = now_ms;
}
}
ReceivePacket(packet);
// Update receive statistics after ReceivePacket.
@ -942,12 +919,21 @@ void RtpVideoStreamReceiver::UpdateRtt(int64_t max_rtt_ms) {
}
absl::optional<int64_t> RtpVideoStreamReceiver::LastReceivedPacketMs() const {
return packet_buffer_.LastReceivedPacketMs();
MutexLock lock(&sync_info_lock_);
if (last_received_rtp_system_time_) {
return absl::optional<int64_t>(last_received_rtp_system_time_->ms());
}
return absl::nullopt;
}
absl::optional<int64_t> RtpVideoStreamReceiver::LastReceivedKeyframePacketMs()
const {
return packet_buffer_.LastReceivedKeyframePacketMs();
MutexLock lock(&sync_info_lock_);
if (last_received_keyframe_rtp_system_time_) {
return absl::optional<int64_t>(
last_received_keyframe_rtp_system_time_->ms());
}
return absl::nullopt;
}
void RtpVideoStreamReceiver::AddSecondarySink(RtpPacketSinkInterface* sink) {
@ -1183,4 +1169,38 @@ void RtpVideoStreamReceiver::InsertSpsPpsIntoTracker(uint8_t payload_type) {
sprop_decoder.pps_nalu());
}
void RtpVideoStreamReceiver::UpdatePacketReceiveTimestamps(
const RtpPacketReceived& packet,
bool is_keyframe) {
Timestamp now = clock_->CurrentTime();
{
MutexLock lock(&sync_info_lock_);
if (is_keyframe) {
last_received_keyframe_rtp_system_time_ = now;
}
last_received_rtp_system_time_ = now;
last_received_rtp_timestamp_ = packet.Timestamp();
}
// Periodically log the RTP header of incoming packets.
if (now.ms() - last_packet_log_ms_ > kPacketLogIntervalMs) {
rtc::StringBuilder ss;
ss << "Packet received on SSRC: " << packet.Ssrc()
<< " with payload type: " << static_cast<int>(packet.PayloadType())
<< ", timestamp: " << packet.Timestamp()
<< ", sequence number: " << packet.SequenceNumber()
<< ", arrival time: " << packet.arrival_time_ms();
int32_t time_offset;
if (packet.GetExtension<TransmissionOffset>(&time_offset)) {
ss << ", toffset: " << time_offset;
}
uint32_t send_time;
if (packet.GetExtension<AbsoluteSendTime>(&send_time)) {
ss << ", abs send time: " << send_time;
}
RTC_LOG(LS_INFO) << ss.str();
last_packet_log_ms_ = now.ms();
}
}
} // namespace webrtc

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@ -22,6 +22,7 @@
#include "api/array_view.h"
#include "api/crypto/frame_decryptor_interface.h"
#include "api/sequence_checker.h"
#include "api/units/timestamp.h"
#include "api/video/color_space.h"
#include "api/video_codecs/video_codec.h"
#include "call/rtp_packet_sink_interface.h"
@ -303,6 +304,9 @@ class RtpVideoStreamReceiver : public LossNotificationSender,
const RtpPacketReceived& rtp_packet,
RTPVideoHeader* video_header) RTC_RUN_ON(worker_task_checker_);
void OnAssembledFrame(std::unique_ptr<RtpFrameObject> frame);
void UpdatePacketReceiveTimestamps(const RtpPacketReceived& packet,
bool is_keyframe)
RTC_RUN_ON(worker_task_checker_);
Clock* const clock_;
// Ownership of this object lies with VideoReceiveStream, which owns |this|.
@ -378,7 +382,9 @@ class RtpVideoStreamReceiver : public LossNotificationSender,
mutable Mutex sync_info_lock_;
absl::optional<uint32_t> last_received_rtp_timestamp_
RTC_GUARDED_BY(sync_info_lock_);
absl::optional<int64_t> last_received_rtp_system_time_ms_
absl::optional<Timestamp> last_received_rtp_system_time_
RTC_GUARDED_BY(sync_info_lock_);
absl::optional<Timestamp> last_received_keyframe_rtp_system_time_
RTC_GUARDED_BY(sync_info_lock_);
// Used to validate the buffered frame decryptor is always run on the correct

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@ -250,7 +250,7 @@ RtpVideoStreamReceiver2::RtpVideoStreamReceiver2(
clock_,
&rtcp_feedback_buffer_,
&rtcp_feedback_buffer_)),
packet_buffer_(clock_, kPacketBufferStartSize, PacketBufferMaxSize()),
packet_buffer_(kPacketBufferStartSize, PacketBufferMaxSize()),
has_received_frame_(false),
frames_decryptable_(false),
absolute_capture_time_receiver_(clock) {
@ -353,11 +353,11 @@ absl::optional<Syncable::Info> RtpVideoStreamReceiver2::GetSyncInfo() const {
return absl::nullopt;
}
if (!last_received_rtp_timestamp_ || !last_received_rtp_system_time_ms_) {
if (!last_received_rtp_timestamp_ || !last_received_rtp_system_time_) {
return absl::nullopt;
}
info.latest_received_capture_timestamp = *last_received_rtp_timestamp_;
info.latest_receive_time_ms = *last_received_rtp_system_time_ms_;
info.latest_receive_time_ms = last_received_rtp_system_time_->ms();
// Leaves info.current_delay_ms uninitialized.
return info;
@ -511,6 +511,12 @@ void RtpVideoStreamReceiver2::OnReceivedPayloadData(
ParseGenericDependenciesResult generic_descriptor_state =
ParseGenericDependenciesExtension(rtp_packet, &video_header);
if (!rtp_packet.recovered()) {
UpdatePacketReceiveTimestamps(
rtp_packet, video_header.frame_type == VideoFrameType::kVideoFrameKey);
}
if (generic_descriptor_state == kDropPacket)
return;
@ -639,34 +645,6 @@ void RtpVideoStreamReceiver2::OnRtpPacket(const RtpPacketReceived& packet) {
return;
}
if (!packet.recovered()) {
// TODO(nisse): Exclude out-of-order packets?
int64_t now_ms = clock_->TimeInMilliseconds();
last_received_rtp_timestamp_ = packet.Timestamp();
last_received_rtp_system_time_ms_ = now_ms;
// Periodically log the RTP header of incoming packets.
if (now_ms - last_packet_log_ms_ > kPacketLogIntervalMs) {
rtc::StringBuilder ss;
ss << "Packet received on SSRC: " << packet.Ssrc()
<< " with payload type: " << static_cast<int>(packet.PayloadType())
<< ", timestamp: " << packet.Timestamp()
<< ", sequence number: " << packet.SequenceNumber()
<< ", arrival time: " << packet.arrival_time_ms();
int32_t time_offset;
if (packet.GetExtension<TransmissionOffset>(&time_offset)) {
ss << ", toffset: " << time_offset;
}
uint32_t send_time;
if (packet.GetExtension<AbsoluteSendTime>(&send_time)) {
ss << ", abs send time: " << send_time;
}
RTC_LOG(LS_INFO) << ss.str();
last_packet_log_ms_ = now_ms;
}
}
ReceivePacket(packet);
// Update receive statistics after ReceivePacket.
@ -915,12 +893,20 @@ void RtpVideoStreamReceiver2::UpdateRtt(int64_t max_rtt_ms) {
absl::optional<int64_t> RtpVideoStreamReceiver2::LastReceivedPacketMs() const {
RTC_DCHECK_RUN_ON(&worker_task_checker_);
return last_received_rtp_system_time_ms_;
if (last_received_rtp_system_time_) {
return absl::optional<int64_t>(last_received_rtp_system_time_->ms());
}
return absl::nullopt;
}
absl::optional<int64_t> RtpVideoStreamReceiver2::LastReceivedKeyframePacketMs()
const {
return packet_buffer_.LastReceivedKeyframePacketMs();
RTC_DCHECK_RUN_ON(&worker_task_checker_);
if (last_received_keyframe_rtp_system_time_) {
return absl::optional<int64_t>(
last_received_keyframe_rtp_system_time_->ms());
}
return absl::nullopt;
}
void RtpVideoStreamReceiver2::ManageFrame(
@ -1137,4 +1123,35 @@ void RtpVideoStreamReceiver2::InsertSpsPpsIntoTracker(uint8_t payload_type) {
sprop_decoder.pps_nalu());
}
void RtpVideoStreamReceiver2::UpdatePacketReceiveTimestamps(
const RtpPacketReceived& packet,
bool is_keyframe) {
Timestamp now = clock_->CurrentTime();
if (is_keyframe) {
last_received_keyframe_rtp_system_time_ = now;
}
last_received_rtp_system_time_ = now;
last_received_rtp_timestamp_ = packet.Timestamp();
// Periodically log the RTP header of incoming packets.
if (now.ms() - last_packet_log_ms_ > kPacketLogIntervalMs) {
rtc::StringBuilder ss;
ss << "Packet received on SSRC: " << packet.Ssrc()
<< " with payload type: " << static_cast<int>(packet.PayloadType())
<< ", timestamp: " << packet.Timestamp()
<< ", sequence number: " << packet.SequenceNumber()
<< ", arrival time: " << packet.arrival_time_ms();
int32_t time_offset;
if (packet.GetExtension<TransmissionOffset>(&time_offset)) {
ss << ", toffset: " << time_offset;
}
uint32_t send_time;
if (packet.GetExtension<AbsoluteSendTime>(&send_time)) {
ss << ", abs send time: " << send_time;
}
RTC_LOG(LS_INFO) << ss.str();
last_packet_log_ms_ = now.ms();
}
}
} // namespace webrtc

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@ -19,6 +19,7 @@
#include "absl/types/optional.h"
#include "api/crypto/frame_decryptor_interface.h"
#include "api/sequence_checker.h"
#include "api/units/timestamp.h"
#include "api/video/color_space.h"
#include "api/video_codecs/video_codec.h"
#include "call/rtp_packet_sink_interface.h"
@ -260,6 +261,9 @@ class RtpVideoStreamReceiver2 : public LossNotificationSender,
const RtpPacketReceived& rtp_packet,
RTPVideoHeader* video_header) RTC_RUN_ON(worker_task_checker_);
void OnAssembledFrame(std::unique_ptr<RtpFrameObject> frame);
void UpdatePacketReceiveTimestamps(const RtpPacketReceived& packet,
bool is_keyframe)
RTC_RUN_ON(worker_task_checker_);
Clock* const clock_;
// Ownership of this object lies with VideoReceiveStream, which owns |this|.
@ -331,7 +335,9 @@ class RtpVideoStreamReceiver2 : public LossNotificationSender,
absl::optional<uint32_t> last_received_rtp_timestamp_
RTC_GUARDED_BY(worker_task_checker_);
absl::optional<int64_t> last_received_rtp_system_time_ms_
absl::optional<Timestamp> last_received_rtp_system_time_
RTC_GUARDED_BY(worker_task_checker_);
absl::optional<Timestamp> last_received_keyframe_rtp_system_time_
RTC_GUARDED_BY(worker_task_checker_);
// Handles incoming encrypted frames and forwards them to the