blob: 284a50185e13c9f7e410c3c03dab63021469baef [file] [log] [blame]
/*
* Copyright (c) 2012 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.
*/
#include "video/rtp_video_stream_receiver2.h"
#include <algorithm>
#include <limits>
#include <memory>
#include <utility>
#include <vector>
#include "absl/algorithm/container.h"
#include "absl/memory/memory.h"
#include "absl/types/optional.h"
#include "api/video/video_codec_type.h"
#include "media/base/media_constants.h"
#include "modules/pacing/packet_router.h"
#include "modules/remote_bitrate_estimator/include/remote_bitrate_estimator.h"
#include "modules/rtp_rtcp/include/receive_statistics.h"
#include "modules/rtp_rtcp/include/rtp_cvo.h"
#include "modules/rtp_rtcp/source/create_video_rtp_depacketizer.h"
#include "modules/rtp_rtcp/source/rtp_dependency_descriptor_extension.h"
#include "modules/rtp_rtcp/source/rtp_format.h"
#include "modules/rtp_rtcp/source/rtp_generic_frame_descriptor.h"
#include "modules/rtp_rtcp/source/rtp_generic_frame_descriptor_extension.h"
#include "modules/rtp_rtcp/source/rtp_header_extensions.h"
#include "modules/rtp_rtcp/source/rtp_packet_received.h"
#include "modules/rtp_rtcp/source/rtp_rtcp_config.h"
#include "modules/rtp_rtcp/source/ulpfec_receiver.h"
#include "modules/rtp_rtcp/source/video_rtp_depacketizer.h"
#include "modules/rtp_rtcp/source/video_rtp_depacketizer_raw.h"
#include "modules/video_coding/frame_object.h"
#include "modules/video_coding/h264_sprop_parameter_sets.h"
#include "modules/video_coding/h264_sps_pps_tracker.h"
#include "modules/video_coding/nack_requester.h"
#include "modules/video_coding/packet_buffer.h"
#include "rtc_base/checks.h"
#include "rtc_base/location.h"
#include "rtc_base/logging.h"
#include "rtc_base/strings/string_builder.h"
#include "system_wrappers/include/metrics.h"
#include "system_wrappers/include/ntp_time.h"
namespace webrtc {
namespace {
// TODO(philipel): Change kPacketBufferStartSize back to 32 in M63 see:
// crbug.com/752886
constexpr int kPacketBufferStartSize = 512;
constexpr int kPacketBufferMaxSize = 2048;
constexpr int kMaxPacketAgeToNack = 450;
int PacketBufferMaxSize(const FieldTrialsView& field_trials) {
// The group here must be a positive power of 2, in which case that is used as
// size. All other values shall result in the default value being used.
const std::string group_name =
field_trials.Lookup("WebRTC-PacketBufferMaxSize");
int packet_buffer_max_size = kPacketBufferMaxSize;
if (!group_name.empty() &&
(sscanf(group_name.c_str(), "%d", &packet_buffer_max_size) != 1 ||
packet_buffer_max_size <= 0 ||
// Verify that the number is a positive power of 2.
(packet_buffer_max_size & (packet_buffer_max_size - 1)) != 0)) {
RTC_LOG(LS_WARNING) << "Invalid packet buffer max size: " << group_name;
packet_buffer_max_size = kPacketBufferMaxSize;
}
return packet_buffer_max_size;
}
std::unique_ptr<ModuleRtpRtcpImpl2> CreateRtpRtcpModule(
Clock* clock,
ReceiveStatistics* receive_statistics,
Transport* outgoing_transport,
RtcpRttStats* rtt_stats,
RtcpPacketTypeCounterObserver* rtcp_packet_type_counter_observer,
RtcpCnameCallback* rtcp_cname_callback,
bool non_sender_rtt_measurement,
uint32_t local_ssrc) {
RtpRtcpInterface::Configuration configuration;
configuration.clock = clock;
configuration.audio = false;
configuration.receiver_only = true;
configuration.receive_statistics = receive_statistics;
configuration.outgoing_transport = outgoing_transport;
configuration.rtt_stats = rtt_stats;
configuration.rtcp_packet_type_counter_observer =
rtcp_packet_type_counter_observer;
configuration.rtcp_cname_callback = rtcp_cname_callback;
configuration.local_media_ssrc = local_ssrc;
configuration.non_sender_rtt_measurement = non_sender_rtt_measurement;
std::unique_ptr<ModuleRtpRtcpImpl2> rtp_rtcp =
ModuleRtpRtcpImpl2::Create(configuration);
rtp_rtcp->SetRTCPStatus(RtcpMode::kCompound);
return rtp_rtcp;
}
std::unique_ptr<NackRequester> MaybeConstructNackModule(
TaskQueueBase* current_queue,
NackPeriodicProcessor* nack_periodic_processor,
const NackConfig& nack,
Clock* clock,
NackSender* nack_sender,
KeyFrameRequestSender* keyframe_request_sender,
const FieldTrialsView& field_trials) {
if (nack.rtp_history_ms == 0)
return nullptr;
// TODO(bugs.webrtc.org/12420): pass rtp_history_ms to the nack module.
return std::make_unique<NackRequester>(current_queue, nack_periodic_processor,
clock, nack_sender,
keyframe_request_sender, field_trials);
}
static const int kPacketLogIntervalMs = 10000;
} // namespace
RtpVideoStreamReceiver2::RtcpFeedbackBuffer::RtcpFeedbackBuffer(
KeyFrameRequestSender* key_frame_request_sender,
NackSender* nack_sender,
LossNotificationSender* loss_notification_sender)
: key_frame_request_sender_(key_frame_request_sender),
nack_sender_(nack_sender),
loss_notification_sender_(loss_notification_sender),
request_key_frame_(false) {
RTC_DCHECK(key_frame_request_sender_);
RTC_DCHECK(nack_sender_);
RTC_DCHECK(loss_notification_sender_);
packet_sequence_checker_.Detach();
}
void RtpVideoStreamReceiver2::RtcpFeedbackBuffer::RequestKeyFrame() {
RTC_DCHECK_RUN_ON(&packet_sequence_checker_);
request_key_frame_ = true;
}
void RtpVideoStreamReceiver2::RtcpFeedbackBuffer::SendNack(
const std::vector<uint16_t>& sequence_numbers,
bool buffering_allowed) {
RTC_DCHECK_RUN_ON(&packet_sequence_checker_);
RTC_DCHECK(!sequence_numbers.empty());
nack_sequence_numbers_.insert(nack_sequence_numbers_.end(),
sequence_numbers.cbegin(),
sequence_numbers.cend());
if (!buffering_allowed) {
// Note that while *buffering* is not allowed, *batching* is, meaning that
// previously buffered messages may be sent along with the current message.
SendBufferedRtcpFeedback();
}
}
void RtpVideoStreamReceiver2::RtcpFeedbackBuffer::SendLossNotification(
uint16_t last_decoded_seq_num,
uint16_t last_received_seq_num,
bool decodability_flag,
bool buffering_allowed) {
RTC_DCHECK_RUN_ON(&packet_sequence_checker_);
RTC_DCHECK(buffering_allowed);
RTC_DCHECK(!lntf_state_)
<< "SendLossNotification() called twice in a row with no call to "
"SendBufferedRtcpFeedback() in between.";
lntf_state_ = absl::make_optional<LossNotificationState>(
last_decoded_seq_num, last_received_seq_num, decodability_flag);
}
void RtpVideoStreamReceiver2::RtcpFeedbackBuffer::SendBufferedRtcpFeedback() {
RTC_DCHECK_RUN_ON(&packet_sequence_checker_);
bool request_key_frame = false;
std::vector<uint16_t> nack_sequence_numbers;
absl::optional<LossNotificationState> lntf_state;
std::swap(request_key_frame, request_key_frame_);
std::swap(nack_sequence_numbers, nack_sequence_numbers_);
std::swap(lntf_state, lntf_state_);
if (lntf_state) {
// If either a NACK or a key frame request is sent, we should buffer
// the LNTF and wait for them (NACK or key frame request) to trigger
// the compound feedback message.
// Otherwise, the LNTF should be sent out immediately.
const bool buffering_allowed =
request_key_frame || !nack_sequence_numbers.empty();
loss_notification_sender_->SendLossNotification(
lntf_state->last_decoded_seq_num, lntf_state->last_received_seq_num,
lntf_state->decodability_flag, buffering_allowed);
}
if (request_key_frame) {
key_frame_request_sender_->RequestKeyFrame();
} else if (!nack_sequence_numbers.empty()) {
nack_sender_->SendNack(nack_sequence_numbers, true);
}
}
void RtpVideoStreamReceiver2::RtcpFeedbackBuffer::ClearLossNotificationState() {
RTC_DCHECK_RUN_ON(&packet_sequence_checker_);
lntf_state_.reset();
}
RtpVideoStreamReceiver2::RtpVideoStreamReceiver2(
TaskQueueBase* current_queue,
Clock* clock,
Transport* transport,
RtcpRttStats* rtt_stats,
PacketRouter* packet_router,
const VideoReceiveStreamInterface::Config* config,
ReceiveStatistics* rtp_receive_statistics,
RtcpPacketTypeCounterObserver* rtcp_packet_type_counter_observer,
RtcpCnameCallback* rtcp_cname_callback,
NackPeriodicProcessor* nack_periodic_processor,
OnCompleteFrameCallback* complete_frame_callback,
rtc::scoped_refptr<FrameDecryptorInterface> frame_decryptor,
rtc::scoped_refptr<FrameTransformerInterface> frame_transformer,
const FieldTrialsView& field_trials)
: field_trials_(field_trials),
worker_queue_(current_queue),
clock_(clock),
config_(*config),
packet_router_(packet_router),
ntp_estimator_(clock),
rtp_header_extensions_(config_.rtp.extensions),
forced_playout_delay_max_ms_("max_ms", absl::nullopt),
forced_playout_delay_min_ms_("min_ms", absl::nullopt),
rtp_receive_statistics_(rtp_receive_statistics),
ulpfec_receiver_(
std::make_unique<UlpfecReceiver>(config->rtp.remote_ssrc,
config_.rtp.ulpfec_payload_type,
this,
config->rtp.extensions,
clock)),
packet_sink_(config->rtp.packet_sink_),
receiving_(false),
last_packet_log_ms_(-1),
rtp_rtcp_(CreateRtpRtcpModule(
clock,
rtp_receive_statistics_,
transport,
rtt_stats,
rtcp_packet_type_counter_observer,
rtcp_cname_callback,
config_.rtp.rtcp_xr.receiver_reference_time_report,
config_.rtp.local_ssrc)),
nack_periodic_processor_(nack_periodic_processor),
complete_frame_callback_(complete_frame_callback),
keyframe_request_method_(config_.rtp.keyframe_method),
// TODO(bugs.webrtc.org/10336): Let `rtcp_feedback_buffer_` communicate
// directly with `rtp_rtcp_`.
rtcp_feedback_buffer_(this, this, this),
nack_module_(MaybeConstructNackModule(current_queue,
nack_periodic_processor,
config_.rtp.nack,
clock_,
&rtcp_feedback_buffer_,
&rtcp_feedback_buffer_,
field_trials_)),
packet_buffer_(kPacketBufferStartSize,
PacketBufferMaxSize(field_trials_)),
reference_finder_(std::make_unique<RtpFrameReferenceFinder>()),
has_received_frame_(false),
frames_decryptable_(false),
absolute_capture_time_interpolator_(clock) {
packet_sequence_checker_.Detach();
constexpr bool remb_candidate = true;
if (packet_router_)
packet_router_->AddReceiveRtpModule(rtp_rtcp_.get(), remb_candidate);
RTC_DCHECK(config_.rtp.rtcp_mode != RtcpMode::kOff)
<< "A stream should not be configured with RTCP disabled. This value is "
"reserved for internal usage.";
// TODO(pbos): What's an appropriate local_ssrc for receive-only streams?
RTC_DCHECK(config_.rtp.local_ssrc != 0);
RTC_DCHECK(config_.rtp.remote_ssrc != config_.rtp.local_ssrc);
rtp_rtcp_->SetRTCPStatus(config_.rtp.rtcp_mode);
rtp_rtcp_->SetRemoteSSRC(config_.rtp.remote_ssrc);
if (config_.rtp.nack.rtp_history_ms > 0) {
rtp_receive_statistics_->SetMaxReorderingThreshold(config_.rtp.remote_ssrc,
kMaxPacketAgeToNack);
}
ParseFieldTrial(
{&forced_playout_delay_max_ms_, &forced_playout_delay_min_ms_},
field_trials_.Lookup("WebRTC-ForcePlayoutDelay"));
if (config_.rtp.lntf.enabled) {
loss_notification_controller_ =
std::make_unique<LossNotificationController>(&rtcp_feedback_buffer_,
&rtcp_feedback_buffer_);
}
// Only construct the encrypted receiver if frame encryption is enabled.
if (config_.crypto_options.sframe.require_frame_encryption) {
buffered_frame_decryptor_ =
std::make_unique<BufferedFrameDecryptor>(this, this, field_trials_);
if (frame_decryptor != nullptr) {
buffered_frame_decryptor_->SetFrameDecryptor(std::move(frame_decryptor));
}
}
if (frame_transformer) {
frame_transformer_delegate_ =
rtc::make_ref_counted<RtpVideoStreamReceiverFrameTransformerDelegate>(
this, std::move(frame_transformer), rtc::Thread::Current(),
config_.rtp.remote_ssrc);
frame_transformer_delegate_->Init();
}
}
RtpVideoStreamReceiver2::~RtpVideoStreamReceiver2() {
if (packet_router_)
packet_router_->RemoveReceiveRtpModule(rtp_rtcp_.get());
ulpfec_receiver_.reset();
if (frame_transformer_delegate_)
frame_transformer_delegate_->Reset();
}
void RtpVideoStreamReceiver2::AddReceiveCodec(
uint8_t payload_type,
VideoCodecType video_codec,
const std::map<std::string, std::string>& codec_params,
bool raw_payload) {
RTC_DCHECK_RUN_ON(&packet_sequence_checker_);
if (codec_params.count(cricket::kH264FmtpSpsPpsIdrInKeyframe) ||
field_trials_.IsEnabled("WebRTC-SpsPpsIdrIsH264Keyframe")) {
packet_buffer_.ForceSpsPpsIdrIsH264Keyframe();
}
payload_type_map_.emplace(
payload_type, raw_payload ? std::make_unique<VideoRtpDepacketizerRaw>()
: CreateVideoRtpDepacketizer(video_codec));
pt_codec_params_.emplace(payload_type, codec_params);
}
absl::optional<Syncable::Info> RtpVideoStreamReceiver2::GetSyncInfo() const {
RTC_DCHECK_RUN_ON(&packet_sequence_checker_);
Syncable::Info info;
if (rtp_rtcp_->RemoteNTP(&info.capture_time_ntp_secs,
&info.capture_time_ntp_frac,
/*rtcp_arrival_time_secs=*/nullptr,
/*rtcp_arrival_time_frac=*/nullptr,
&info.capture_time_source_clock) != 0) {
return absl::nullopt;
}
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();
// Leaves info.current_delay_ms uninitialized.
return info;
}
RtpVideoStreamReceiver2::ParseGenericDependenciesResult
RtpVideoStreamReceiver2::ParseGenericDependenciesExtension(
const RtpPacketReceived& rtp_packet,
RTPVideoHeader* video_header) {
RTC_DCHECK_RUN_ON(&packet_sequence_checker_);
if (rtp_packet.HasExtension<RtpDependencyDescriptorExtension>()) {
webrtc::DependencyDescriptor dependency_descriptor;
if (!rtp_packet.GetExtension<RtpDependencyDescriptorExtension>(
video_structure_.get(), &dependency_descriptor)) {
// Descriptor is there, but failed to parse. Either it is invalid,
// or too old packet (after relevant video_structure_ changed),
// or too new packet (before relevant video_structure_ arrived).
// Drop such packet to be on the safe side.
// TODO(bugs.webrtc.org/10342): Stash too new packet.
RTC_LOG(LS_WARNING) << "ssrc: " << rtp_packet.Ssrc()
<< " Failed to parse dependency descriptor.";
return kDropPacket;
}
if (dependency_descriptor.attached_structure != nullptr &&
!dependency_descriptor.first_packet_in_frame) {
RTC_LOG(LS_WARNING) << "ssrc: " << rtp_packet.Ssrc()
<< "Invalid dependency descriptor: structure "
"attached to non first packet of a frame.";
return kDropPacket;
}
video_header->is_first_packet_in_frame =
dependency_descriptor.first_packet_in_frame;
video_header->is_last_packet_in_frame =
dependency_descriptor.last_packet_in_frame;
int64_t frame_id =
frame_id_unwrapper_.Unwrap(dependency_descriptor.frame_number);
auto& generic_descriptor_info = video_header->generic.emplace();
generic_descriptor_info.frame_id = frame_id;
generic_descriptor_info.spatial_index =
dependency_descriptor.frame_dependencies.spatial_id;
generic_descriptor_info.temporal_index =
dependency_descriptor.frame_dependencies.temporal_id;
for (int fdiff : dependency_descriptor.frame_dependencies.frame_diffs) {
generic_descriptor_info.dependencies.push_back(frame_id - fdiff);
}
generic_descriptor_info.decode_target_indications =
dependency_descriptor.frame_dependencies.decode_target_indications;
if (dependency_descriptor.resolution) {
video_header->width = dependency_descriptor.resolution->Width();
video_header->height = dependency_descriptor.resolution->Height();
}
// FrameDependencyStructure is sent in dependency descriptor of the first
// packet of a key frame and required for parsed dependency descriptor in
// all the following packets until next key frame.
// Save it if there is a (potentially) new structure.
if (dependency_descriptor.attached_structure) {
RTC_DCHECK(dependency_descriptor.first_packet_in_frame);
if (video_structure_frame_id_ > frame_id) {
RTC_LOG(LS_WARNING)
<< "Arrived key frame with id " << frame_id << " and structure id "
<< dependency_descriptor.attached_structure->structure_id
<< " is older than the latest received key frame with id "
<< *video_structure_frame_id_ << " and structure id "
<< video_structure_->structure_id;
return kDropPacket;
}
video_structure_ = std::move(dependency_descriptor.attached_structure);
video_structure_frame_id_ = frame_id;
video_header->frame_type = VideoFrameType::kVideoFrameKey;
} else {
video_header->frame_type = VideoFrameType::kVideoFrameDelta;
}
return kHasGenericDescriptor;
}
RtpGenericFrameDescriptor generic_frame_descriptor;
if (!rtp_packet.GetExtension<RtpGenericFrameDescriptorExtension00>(
&generic_frame_descriptor)) {
return kNoGenericDescriptor;
}
video_header->is_first_packet_in_frame =
generic_frame_descriptor.FirstPacketInSubFrame();
video_header->is_last_packet_in_frame =
generic_frame_descriptor.LastPacketInSubFrame();
if (generic_frame_descriptor.FirstPacketInSubFrame()) {
video_header->frame_type =
generic_frame_descriptor.FrameDependenciesDiffs().empty()
? VideoFrameType::kVideoFrameKey
: VideoFrameType::kVideoFrameDelta;
auto& generic_descriptor_info = video_header->generic.emplace();
int64_t frame_id =
frame_id_unwrapper_.Unwrap(generic_frame_descriptor.FrameId());
generic_descriptor_info.frame_id = frame_id;
generic_descriptor_info.spatial_index =
generic_frame_descriptor.SpatialLayer();
generic_descriptor_info.temporal_index =
generic_frame_descriptor.TemporalLayer();
for (uint16_t fdiff : generic_frame_descriptor.FrameDependenciesDiffs()) {
generic_descriptor_info.dependencies.push_back(frame_id - fdiff);
}
}
video_header->width = generic_frame_descriptor.Width();
video_header->height = generic_frame_descriptor.Height();
return kHasGenericDescriptor;
}
void RtpVideoStreamReceiver2::OnReceivedPayloadData(
rtc::CopyOnWriteBuffer codec_payload,
const RtpPacketReceived& rtp_packet,
const RTPVideoHeader& video) {
RTC_DCHECK_RUN_ON(&packet_sequence_checker_);
auto packet =
std::make_unique<video_coding::PacketBuffer::Packet>(rtp_packet, video);
int64_t unwrapped_rtp_seq_num =
rtp_seq_num_unwrapper_.Unwrap(rtp_packet.SequenceNumber());
auto& packet_info =
packet_infos_
.emplace(
unwrapped_rtp_seq_num,
RtpPacketInfo(
rtp_packet.Ssrc(), rtp_packet.Csrcs(), rtp_packet.Timestamp(),
/*audio_level=*/absl::nullopt,
rtp_packet.GetExtension<AbsoluteCaptureTimeExtension>(),
/*receive_time_ms=*/clock_->CurrentTime()))
.first->second;
// Try to extrapolate absolute capture time if it is missing.
packet_info.set_absolute_capture_time(
absolute_capture_time_interpolator_.OnReceivePacket(
AbsoluteCaptureTimeInterpolator::GetSource(packet_info.ssrc(),
packet_info.csrcs()),
packet_info.rtp_timestamp(),
// Assume frequency is the same one for all video frames.
kVideoPayloadTypeFrequency, packet_info.absolute_capture_time()));
RTPVideoHeader& video_header = packet->video_header;
video_header.rotation = kVideoRotation_0;
video_header.content_type = VideoContentType::UNSPECIFIED;
video_header.video_timing.flags = VideoSendTiming::kInvalid;
video_header.is_last_packet_in_frame |= rtp_packet.Marker();
rtp_packet.GetExtension<VideoOrientation>(&video_header.rotation);
rtp_packet.GetExtension<VideoContentTypeExtension>(
&video_header.content_type);
rtp_packet.GetExtension<VideoTimingExtension>(&video_header.video_timing);
if (forced_playout_delay_max_ms_ && forced_playout_delay_min_ms_) {
video_header.playout_delay.max_ms = *forced_playout_delay_max_ms_;
video_header.playout_delay.min_ms = *forced_playout_delay_min_ms_;
} else {
rtp_packet.GetExtension<PlayoutDelayLimits>(&video_header.playout_delay);
}
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) {
Timestamp now = clock_->CurrentTime();
if (video_structure_ == nullptr &&
next_keyframe_request_for_missing_video_structure_ < now) {
// No video structure received yet, most likely part of the initial
// keyframe was lost.
RequestKeyFrame();
next_keyframe_request_for_missing_video_structure_ =
now + TimeDelta::Seconds(1);
}
return;
}
// Color space should only be transmitted in the last packet of a frame,
// therefore, neglect it otherwise so that last_color_space_ is not reset by
// mistake.
if (video_header.is_last_packet_in_frame) {
video_header.color_space = rtp_packet.GetExtension<ColorSpaceExtension>();
if (video_header.color_space ||
video_header.frame_type == VideoFrameType::kVideoFrameKey) {
// Store color space since it's only transmitted when changed or for key
// frames. Color space will be cleared if a key frame is transmitted
// without color space information.
last_color_space_ = video_header.color_space;
} else if (last_color_space_) {
video_header.color_space = last_color_space_;
}
}
video_header.video_frame_tracking_id =
rtp_packet.GetExtension<VideoFrameTrackingIdExtension>();
if (loss_notification_controller_) {
if (rtp_packet.recovered()) {
// TODO(bugs.webrtc.org/10336): Implement support for reordering.
RTC_LOG(LS_INFO)
<< "LossNotificationController does not support reordering.";
} else if (generic_descriptor_state == kNoGenericDescriptor) {
RTC_LOG(LS_WARNING) << "LossNotificationController requires generic "
"frame descriptor, but it is missing.";
} else {
if (video_header.is_first_packet_in_frame) {
RTC_DCHECK(video_header.generic);
LossNotificationController::FrameDetails frame;
frame.is_keyframe =
video_header.frame_type == VideoFrameType::kVideoFrameKey;
frame.frame_id = video_header.generic->frame_id;
frame.frame_dependencies = video_header.generic->dependencies;
loss_notification_controller_->OnReceivedPacket(
rtp_packet.SequenceNumber(), &frame);
} else {
loss_notification_controller_->OnReceivedPacket(
rtp_packet.SequenceNumber(), nullptr);
}
}
}
if (nack_module_) {
const bool is_keyframe =
video_header.is_first_packet_in_frame &&
video_header.frame_type == VideoFrameType::kVideoFrameKey;
packet->times_nacked = nack_module_->OnReceivedPacket(
rtp_packet.SequenceNumber(), is_keyframe, rtp_packet.recovered());
} else {
packet->times_nacked = -1;
}
if (codec_payload.size() == 0) {
NotifyReceiverOfEmptyPacket(packet->seq_num);
rtcp_feedback_buffer_.SendBufferedRtcpFeedback();
return;
}
if (packet->codec() == kVideoCodecH264) {
// Only when we start to receive packets will we know what payload type
// that will be used. When we know the payload type insert the correct
// sps/pps into the tracker.
if (packet->payload_type != last_payload_type_) {
last_payload_type_ = packet->payload_type;
InsertSpsPpsIntoTracker(packet->payload_type);
}
video_coding::H264SpsPpsTracker::FixedBitstream fixed =
tracker_.CopyAndFixBitstream(
rtc::MakeArrayView(codec_payload.cdata(), codec_payload.size()),
&packet->video_header);
switch (fixed.action) {
case video_coding::H264SpsPpsTracker::kRequestKeyframe:
rtcp_feedback_buffer_.RequestKeyFrame();
rtcp_feedback_buffer_.SendBufferedRtcpFeedback();
[[fallthrough]];
case video_coding::H264SpsPpsTracker::kDrop:
return;
case video_coding::H264SpsPpsTracker::kInsert:
packet->video_payload = std::move(fixed.bitstream);
break;
}
} else {
packet->video_payload = std::move(codec_payload);
}
rtcp_feedback_buffer_.SendBufferedRtcpFeedback();
frame_counter_.Add(packet->timestamp);
OnInsertedPacket(packet_buffer_.InsertPacket(std::move(packet)));
}
void RtpVideoStreamReceiver2::OnRecoveredPacket(const uint8_t* rtp_packet,
size_t rtp_packet_length) {
RTC_DCHECK_RUN_ON(&packet_sequence_checker_);
RtpPacketReceived packet;
if (!packet.Parse(rtp_packet, rtp_packet_length))
return;
if (packet.PayloadType() == config_.rtp.red_payload_type) {
RTC_LOG(LS_WARNING) << "Discarding recovered packet with RED encapsulation";
return;
}
packet.IdentifyExtensions(rtp_header_extensions_);
packet.set_payload_type_frequency(kVideoPayloadTypeFrequency);
// TODO(bugs.webrtc.org/7135): UlpfecReceiverImpl::ProcessReceivedFec passes
// both original (decapsulated) media packets and recovered packets to this
// callback. We need a way to distinguish, for setting packet.recovered()
// correctly. Ideally, move RED decapsulation out of the Ulpfec
// implementation.
ReceivePacket(packet);
}
// This method handles both regular RTP packets and packets recovered
// via FlexFEC.
void RtpVideoStreamReceiver2::OnRtpPacket(const RtpPacketReceived& packet) {
RTC_DCHECK_RUN_ON(&packet_sequence_checker_);
if (!receiving_)
return;
ReceivePacket(packet);
// Update receive statistics after ReceivePacket.
// Receive statistics will be reset if the payload type changes (make sure
// that the first packet is included in the stats).
if (!packet.recovered()) {
rtp_receive_statistics_->OnRtpPacket(packet);
}
if (packet_sink_) {
packet_sink_->OnRtpPacket(packet);
}
}
void RtpVideoStreamReceiver2::RequestKeyFrame() {
RTC_DCHECK_RUN_ON(&worker_task_checker_);
// TODO(bugs.webrtc.org/10336): Allow the sender to ignore key frame requests
// issued by anything other than the LossNotificationController if it (the
// sender) is relying on LNTF alone.
if (keyframe_request_method_ == KeyFrameReqMethod::kPliRtcp) {
rtp_rtcp_->SendPictureLossIndication();
} else if (keyframe_request_method_ == KeyFrameReqMethod::kFirRtcp) {
rtp_rtcp_->SendFullIntraRequest();
}
}
void RtpVideoStreamReceiver2::SendNack(
const std::vector<uint16_t>& sequence_numbers,
bool /*buffering_allowed*/) {
rtp_rtcp_->SendNack(sequence_numbers);
}
void RtpVideoStreamReceiver2::SendLossNotification(
uint16_t last_decoded_seq_num,
uint16_t last_received_seq_num,
bool decodability_flag,
bool buffering_allowed) {
RTC_DCHECK(config_.rtp.lntf.enabled);
rtp_rtcp_->SendLossNotification(last_decoded_seq_num, last_received_seq_num,
decodability_flag, buffering_allowed);
}
bool RtpVideoStreamReceiver2::IsDecryptable() const {
RTC_DCHECK_RUN_ON(&worker_task_checker_);
return frames_decryptable_;
}
void RtpVideoStreamReceiver2::OnInsertedPacket(
video_coding::PacketBuffer::InsertResult result) {
RTC_DCHECK_RUN_ON(&packet_sequence_checker_);
RTC_DCHECK_RUN_ON(&worker_task_checker_);
video_coding::PacketBuffer::Packet* first_packet = nullptr;
int max_nack_count;
int64_t min_recv_time;
int64_t max_recv_time;
std::vector<rtc::ArrayView<const uint8_t>> payloads;
RtpPacketInfos::vector_type packet_infos;
bool frame_boundary = true;
for (auto& packet : result.packets) {
// PacketBuffer promisses frame boundaries are correctly set on each
// packet. Document that assumption with the DCHECKs.
RTC_DCHECK_EQ(frame_boundary, packet->is_first_packet_in_frame());
int64_t unwrapped_rtp_seq_num =
rtp_seq_num_unwrapper_.Unwrap(packet->seq_num);
RTC_DCHECK(packet_infos_.count(unwrapped_rtp_seq_num) > 0);
RtpPacketInfo& packet_info = packet_infos_[unwrapped_rtp_seq_num];
if (packet->is_first_packet_in_frame()) {
first_packet = packet.get();
max_nack_count = packet->times_nacked;
min_recv_time = packet_info.receive_time().ms();
max_recv_time = packet_info.receive_time().ms();
} else {
max_nack_count = std::max(max_nack_count, packet->times_nacked);
min_recv_time = std::min(min_recv_time, packet_info.receive_time().ms());
max_recv_time = std::max(max_recv_time, packet_info.receive_time().ms());
}
payloads.emplace_back(packet->video_payload);
packet_infos.push_back(packet_info);
frame_boundary = packet->is_last_packet_in_frame();
if (packet->is_last_packet_in_frame()) {
auto depacketizer_it = payload_type_map_.find(first_packet->payload_type);
RTC_CHECK(depacketizer_it != payload_type_map_.end());
rtc::scoped_refptr<EncodedImageBuffer> bitstream =
depacketizer_it->second->AssembleFrame(payloads);
if (!bitstream) {
// Failed to assemble a frame. Discard and continue.
continue;
}
const video_coding::PacketBuffer::Packet& last_packet = *packet;
OnAssembledFrame(std::make_unique<RtpFrameObject>(
first_packet->seq_num, //
last_packet.seq_num, //
last_packet.marker_bit, //
max_nack_count, //
min_recv_time, //
max_recv_time, //
first_packet->timestamp, //
ntp_estimator_.Estimate(first_packet->timestamp), //
last_packet.video_header.video_timing, //
first_packet->payload_type, //
first_packet->codec(), //
last_packet.video_header.rotation, //
last_packet.video_header.content_type, //
first_packet->video_header, //
last_packet.video_header.color_space, //
RtpPacketInfos(std::move(packet_infos)), //
std::move(bitstream)));
payloads.clear();
packet_infos.clear();
}
}
RTC_DCHECK(frame_boundary);
if (result.buffer_cleared) {
last_received_rtp_system_time_.reset();
last_received_keyframe_rtp_system_time_.reset();
last_received_keyframe_rtp_timestamp_.reset();
packet_infos_.clear();
RequestKeyFrame();
}
}
void RtpVideoStreamReceiver2::OnAssembledFrame(
std::unique_ptr<RtpFrameObject> frame) {
RTC_DCHECK_RUN_ON(&packet_sequence_checker_);
RTC_DCHECK(frame);
const absl::optional<RTPVideoHeader::GenericDescriptorInfo>& descriptor =
frame->GetRtpVideoHeader().generic;
if (loss_notification_controller_ && descriptor) {
loss_notification_controller_->OnAssembledFrame(
frame->first_seq_num(), descriptor->frame_id,
absl::c_linear_search(descriptor->decode_target_indications,
DecodeTargetIndication::kDiscardable),
descriptor->dependencies);
}
// If frames arrive before a key frame, they would not be decodable.
// In that case, request a key frame ASAP.
if (!has_received_frame_) {
if (frame->FrameType() != VideoFrameType::kVideoFrameKey) {
// `loss_notification_controller_`, if present, would have already
// requested a key frame when the first packet for the non-key frame
// had arrived, so no need to replicate the request.
if (!loss_notification_controller_) {
RequestKeyFrame();
}
}
has_received_frame_ = true;
}
// Reset `reference_finder_` if `frame` is new and the codec have changed.
if (current_codec_) {
bool frame_is_newer =
AheadOf(frame->Timestamp(), last_assembled_frame_rtp_timestamp_);
if (frame->codec_type() != current_codec_) {
if (frame_is_newer) {
// When we reset the `reference_finder_` we don't want new picture ids
// to overlap with old picture ids. To ensure that doesn't happen we
// start from the `last_completed_picture_id_` and add an offset in case
// of reordering.
reference_finder_ = std::make_unique<RtpFrameReferenceFinder>(
last_completed_picture_id_ + std::numeric_limits<uint16_t>::max());
current_codec_ = frame->codec_type();
} else {
// Old frame from before the codec switch, discard it.
return;
}
}
if (frame_is_newer) {
last_assembled_frame_rtp_timestamp_ = frame->Timestamp();
}
} else {
current_codec_ = frame->codec_type();
last_assembled_frame_rtp_timestamp_ = frame->Timestamp();
}
if (buffered_frame_decryptor_ != nullptr) {
buffered_frame_decryptor_->ManageEncryptedFrame(std::move(frame));
} else if (frame_transformer_delegate_) {
frame_transformer_delegate_->TransformFrame(std::move(frame));
} else {
OnCompleteFrames(reference_finder_->ManageFrame(std::move(frame)));
}
}
void RtpVideoStreamReceiver2::OnCompleteFrames(
RtpFrameReferenceFinder::ReturnVector frames) {
RTC_DCHECK_RUN_ON(&packet_sequence_checker_);
for (auto& frame : frames) {
last_seq_num_for_pic_id_[frame->Id()] = frame->last_seq_num();
last_completed_picture_id_ =
std::max(last_completed_picture_id_, frame->Id());
complete_frame_callback_->OnCompleteFrame(std::move(frame));
}
}
void RtpVideoStreamReceiver2::OnDecryptedFrame(
std::unique_ptr<RtpFrameObject> frame) {
RTC_DCHECK_RUN_ON(&packet_sequence_checker_);
OnCompleteFrames(reference_finder_->ManageFrame(std::move(frame)));
}
void RtpVideoStreamReceiver2::OnDecryptionStatusChange(
FrameDecryptorInterface::Status status) {
RTC_DCHECK_RUN_ON(&worker_task_checker_);
// Called from BufferedFrameDecryptor::DecryptFrame.
frames_decryptable_ =
(status == FrameDecryptorInterface::Status::kOk) ||
(status == FrameDecryptorInterface::Status::kRecoverable);
}
void RtpVideoStreamReceiver2::SetFrameDecryptor(
rtc::scoped_refptr<FrameDecryptorInterface> frame_decryptor) {
// TODO(bugs.webrtc.org/11993): Update callers or post the operation over to
// the network thread.
RTC_DCHECK_RUN_ON(&packet_sequence_checker_);
if (buffered_frame_decryptor_ == nullptr) {
buffered_frame_decryptor_ =
std::make_unique<BufferedFrameDecryptor>(this, this, field_trials_);
}
buffered_frame_decryptor_->SetFrameDecryptor(std::move(frame_decryptor));
}
void RtpVideoStreamReceiver2::SetDepacketizerToDecoderFrameTransformer(
rtc::scoped_refptr<FrameTransformerInterface> frame_transformer) {
RTC_DCHECK_RUN_ON(&worker_task_checker_);
frame_transformer_delegate_ =
rtc::make_ref_counted<RtpVideoStreamReceiverFrameTransformerDelegate>(
this, std::move(frame_transformer), rtc::Thread::Current(),
config_.rtp.remote_ssrc);
frame_transformer_delegate_->Init();
}
void RtpVideoStreamReceiver2::SetRtpExtensions(
const std::vector<RtpExtension>& extensions) {
RTC_DCHECK_RUN_ON(&packet_sequence_checker_);
rtp_header_extensions_.Reset(extensions);
}
const RtpHeaderExtensionMap& RtpVideoStreamReceiver2::GetRtpExtensions() const {
RTC_DCHECK_RUN_ON(&packet_sequence_checker_);
return rtp_header_extensions_;
}
void RtpVideoStreamReceiver2::UpdateRtt(int64_t max_rtt_ms) {
RTC_DCHECK_RUN_ON(&packet_sequence_checker_);
if (nack_module_)
nack_module_->UpdateRtt(max_rtt_ms);
}
void RtpVideoStreamReceiver2::OnLocalSsrcChange(uint32_t local_ssrc) {
RTC_DCHECK_RUN_ON(&packet_sequence_checker_);
rtp_rtcp_->SetLocalSsrc(local_ssrc);
}
void RtpVideoStreamReceiver2::SetRtcpMode(RtcpMode mode) {
RTC_DCHECK_RUN_ON(&packet_sequence_checker_);
rtp_rtcp_->SetRTCPStatus(mode);
}
void RtpVideoStreamReceiver2::SetPacketSink(
RtpPacketSinkInterface* packet_sink) {
RTC_DCHECK_RUN_ON(&packet_sequence_checker_);
packet_sink_ = packet_sink;
}
void RtpVideoStreamReceiver2::SetLossNotificationEnabled(bool enabled) {
RTC_DCHECK_RUN_ON(&packet_sequence_checker_);
if (enabled && !loss_notification_controller_) {
loss_notification_controller_ =
std::make_unique<LossNotificationController>(&rtcp_feedback_buffer_,
&rtcp_feedback_buffer_);
} else if (!enabled && loss_notification_controller_) {
loss_notification_controller_.reset();
rtcp_feedback_buffer_.ClearLossNotificationState();
}
}
void RtpVideoStreamReceiver2::SetNackHistory(TimeDelta history) {
RTC_DCHECK_RUN_ON(&packet_sequence_checker_);
if (history.ms() == 0) {
nack_module_.reset();
} else if (!nack_module_) {
nack_module_ = std::make_unique<NackRequester>(
worker_queue_, nack_periodic_processor_, clock_, &rtcp_feedback_buffer_,
&rtcp_feedback_buffer_, field_trials_);
}
rtp_receive_statistics_->SetMaxReorderingThreshold(
config_.rtp.remote_ssrc,
history.ms() > 0 ? kMaxPacketAgeToNack : kDefaultMaxReorderingThreshold);
}
absl::optional<int64_t> RtpVideoStreamReceiver2::LastReceivedPacketMs() const {
RTC_DCHECK_RUN_ON(&packet_sequence_checker_);
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 {
RTC_DCHECK_RUN_ON(&packet_sequence_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(
std::unique_ptr<RtpFrameObject> frame) {
RTC_DCHECK_RUN_ON(&packet_sequence_checker_);
OnCompleteFrames(reference_finder_->ManageFrame(std::move(frame)));
}
void RtpVideoStreamReceiver2::ReceivePacket(const RtpPacketReceived& packet) {
RTC_DCHECK_RUN_ON(&packet_sequence_checker_);
if (packet.payload_size() == 0) {
// Padding or keep-alive packet.
// TODO(nisse): Could drop empty packets earlier, but need to figure out how
// they should be counted in stats.
NotifyReceiverOfEmptyPacket(packet.SequenceNumber());
return;
}
if (packet.PayloadType() == config_.rtp.red_payload_type) {
ParseAndHandleEncapsulatingHeader(packet);
return;
}
const auto type_it = payload_type_map_.find(packet.PayloadType());
if (type_it == payload_type_map_.end()) {
return;
}
absl::optional<VideoRtpDepacketizer::ParsedRtpPayload> parsed_payload =
type_it->second->Parse(packet.PayloadBuffer());
if (parsed_payload == absl::nullopt) {
RTC_LOG(LS_WARNING) << "Failed parsing payload.";
return;
}
OnReceivedPayloadData(std::move(parsed_payload->video_payload), packet,
parsed_payload->video_header);
}
void RtpVideoStreamReceiver2::ParseAndHandleEncapsulatingHeader(
const RtpPacketReceived& packet) {
RTC_DCHECK_RUN_ON(&packet_sequence_checker_);
if (packet.PayloadType() == config_.rtp.red_payload_type &&
packet.payload_size() > 0) {
if (packet.payload()[0] == config_.rtp.ulpfec_payload_type) {
// Notify video_receiver about received FEC packets to avoid NACKing these
// packets.
NotifyReceiverOfEmptyPacket(packet.SequenceNumber());
}
if (!ulpfec_receiver_->AddReceivedRedPacket(packet)) {
return;
}
ulpfec_receiver_->ProcessReceivedFec();
}
}
// In the case of a video stream without picture ids and no rtx the
// RtpFrameReferenceFinder will need to know about padding to
// correctly calculate frame references.
void RtpVideoStreamReceiver2::NotifyReceiverOfEmptyPacket(uint16_t seq_num) {
RTC_DCHECK_RUN_ON(&packet_sequence_checker_);
RTC_DCHECK_RUN_ON(&worker_task_checker_);
OnCompleteFrames(reference_finder_->PaddingReceived(seq_num));
OnInsertedPacket(packet_buffer_.InsertPadding(seq_num));
if (nack_module_) {
nack_module_->OnReceivedPacket(seq_num, /* is_keyframe = */ false,
/* is _recovered = */ false);
}
if (loss_notification_controller_) {
// TODO(bugs.webrtc.org/10336): Handle empty packets.
RTC_LOG(LS_WARNING)
<< "LossNotificationController does not expect empty packets.";
}
}
bool RtpVideoStreamReceiver2::DeliverRtcp(const uint8_t* rtcp_packet,
size_t rtcp_packet_length) {
RTC_DCHECK_RUN_ON(&packet_sequence_checker_);
if (!receiving_) {
return false;
}
rtp_rtcp_->IncomingRtcpPacket(rtcp_packet, rtcp_packet_length);
int64_t rtt = 0;
rtp_rtcp_->RTT(config_.rtp.remote_ssrc, &rtt, nullptr, nullptr, nullptr);
if (rtt == 0) {
// Waiting for valid rtt.
return true;
}
uint32_t ntp_secs = 0;
uint32_t ntp_frac = 0;
uint32_t rtp_timestamp = 0;
uint32_t received_ntp_secs = 0;
uint32_t received_ntp_frac = 0;
if (rtp_rtcp_->RemoteNTP(&ntp_secs, &ntp_frac, &received_ntp_secs,
&received_ntp_frac, &rtp_timestamp) != 0) {
// Waiting for RTCP.
return true;
}
NtpTime received_ntp(received_ntp_secs, received_ntp_frac);
int64_t time_since_received =
clock_->CurrentNtpInMilliseconds() - received_ntp.ToMs();
// Don't use old SRs to estimate time.
if (time_since_received <= 1) {
ntp_estimator_.UpdateRtcpTimestamp(
TimeDelta::Millis(rtt), NtpTime(ntp_secs, ntp_frac), rtp_timestamp);
absl::optional<int64_t> remote_to_local_clock_offset =
ntp_estimator_.EstimateRemoteToLocalClockOffset();
if (remote_to_local_clock_offset.has_value()) {
capture_clock_offset_updater_.SetRemoteToLocalClockOffset(
*remote_to_local_clock_offset);
}
}
return true;
}
void RtpVideoStreamReceiver2::FrameContinuous(int64_t picture_id) {
RTC_DCHECK_RUN_ON(&packet_sequence_checker_);
if (!nack_module_)
return;
int seq_num = -1;
auto seq_num_it = last_seq_num_for_pic_id_.find(picture_id);
if (seq_num_it != last_seq_num_for_pic_id_.end())
seq_num = seq_num_it->second;
if (seq_num != -1)
nack_module_->ClearUpTo(seq_num);
}
void RtpVideoStreamReceiver2::FrameDecoded(int64_t picture_id) {
RTC_DCHECK_RUN_ON(&packet_sequence_checker_);
int seq_num = -1;
auto seq_num_it = last_seq_num_for_pic_id_.find(picture_id);
if (seq_num_it != last_seq_num_for_pic_id_.end()) {
seq_num = seq_num_it->second;
last_seq_num_for_pic_id_.erase(last_seq_num_for_pic_id_.begin(),
++seq_num_it);
}
if (seq_num != -1) {
int64_t unwrapped_rtp_seq_num = rtp_seq_num_unwrapper_.Unwrap(seq_num);
packet_infos_.erase(packet_infos_.begin(),
packet_infos_.upper_bound(unwrapped_rtp_seq_num));
packet_buffer_.ClearTo(seq_num);
reference_finder_->ClearTo(seq_num);
}
}
void RtpVideoStreamReceiver2::SignalNetworkState(NetworkState state) {
RTC_DCHECK_RUN_ON(&worker_task_checker_);
rtp_rtcp_->SetRTCPStatus(state == kNetworkUp ? config_.rtp.rtcp_mode
: RtcpMode::kOff);
}
void RtpVideoStreamReceiver2::StartReceive() {
RTC_DCHECK_RUN_ON(&packet_sequence_checker_);
receiving_ = true;
}
void RtpVideoStreamReceiver2::StopReceive() {
RTC_DCHECK_RUN_ON(&packet_sequence_checker_);
receiving_ = false;
}
void RtpVideoStreamReceiver2::InsertSpsPpsIntoTracker(uint8_t payload_type) {
RTC_DCHECK_RUN_ON(&packet_sequence_checker_);
RTC_DCHECK_RUN_ON(&worker_task_checker_);
auto codec_params_it = pt_codec_params_.find(payload_type);
if (codec_params_it == pt_codec_params_.end())
return;
RTC_LOG(LS_INFO) << "Found out of band supplied codec parameters for"
" payload type: "
<< static_cast<int>(payload_type);
H264SpropParameterSets sprop_decoder;
auto sprop_base64_it =
codec_params_it->second.find(cricket::kH264FmtpSpropParameterSets);
if (sprop_base64_it == codec_params_it->second.end())
return;
if (!sprop_decoder.DecodeSprop(sprop_base64_it->second.c_str()))
return;
tracker_.InsertSpsPpsNalus(sprop_decoder.sps_nalu(),
sprop_decoder.pps_nalu());
}
void RtpVideoStreamReceiver2::UpdatePacketReceiveTimestamps(
const RtpPacketReceived& packet,
bool is_keyframe) {
Timestamp now = clock_->CurrentTime();
if (is_keyframe ||
last_received_keyframe_rtp_timestamp_ == packet.Timestamp()) {
last_received_keyframe_rtp_timestamp_ = packet.Timestamp();
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: " << ToString(packet.arrival_time());
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