|  | /* | 
|  | *  Copyright (c) 2015 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 "audio/audio_receive_stream.h" | 
|  |  | 
|  | #include <cstddef> | 
|  | #include <cstdint> | 
|  | #include <map> | 
|  | #include <memory> | 
|  | #include <optional> | 
|  | #include <string> | 
|  | #include <utility> | 
|  | #include <vector> | 
|  |  | 
|  | #include "absl/strings/string_view.h" | 
|  | #include "api/array_view.h" | 
|  | #include "api/audio/audio_frame.h" | 
|  | #include "api/audio/audio_mixer.h" | 
|  | #include "api/audio_codecs/audio_format.h" | 
|  | #include "api/call/audio_sink.h" | 
|  | #include "api/environment/environment.h" | 
|  | #include "api/frame_transformer_interface.h" | 
|  | #include "api/neteq/neteq_factory.h" | 
|  | #include "api/rtp_headers.h" | 
|  | #include "api/scoped_refptr.h" | 
|  | #include "api/sequence_checker.h" | 
|  | #include "api/transport/rtp/rtp_source.h" | 
|  | #include "audio/audio_send_stream.h" | 
|  | #include "audio/audio_state.h" | 
|  | #include "audio/channel_receive.h" | 
|  | #include "audio/conversion.h" | 
|  | #include "call/audio_state.h" | 
|  | #include "call/rtp_config.h" | 
|  | #include "call/rtp_stream_receiver_controller_interface.h" | 
|  | #include "call/syncable.h" | 
|  | #include "rtc_base/checks.h" | 
|  | #include "rtc_base/logging.h" | 
|  | #include "rtc_base/strings/string_builder.h" | 
|  | #include "rtc_base/time_utils.h" | 
|  |  | 
|  | namespace webrtc { | 
|  |  | 
|  | std::string AudioReceiveStreamInterface::Config::Rtp::ToString() const { | 
|  | char ss_buf[1024]; | 
|  | SimpleStringBuilder ss(ss_buf); | 
|  | ss << "{remote_ssrc: " << remote_ssrc; | 
|  | ss << ", local_ssrc: " << local_ssrc; | 
|  | ss << ", nack: " << nack.ToString(); | 
|  | ss << ", rtcp: " | 
|  | << (rtcp_mode == RtcpMode::kCompound | 
|  | ? "compound" | 
|  | : (rtcp_mode == RtcpMode::kReducedSize ? "reducedSize" : "off")); | 
|  | ss << '}'; | 
|  | return ss.str(); | 
|  | } | 
|  |  | 
|  | std::string AudioReceiveStreamInterface::Config::ToString() const { | 
|  | char ss_buf[1024]; | 
|  | SimpleStringBuilder ss(ss_buf); | 
|  | ss << "{rtp: " << rtp.ToString(); | 
|  | ss << ", rtcp_send_transport: " | 
|  | << (rtcp_send_transport ? "(Transport)" : "null"); | 
|  | if (!sync_group.empty()) { | 
|  | ss << ", sync_group: " << sync_group; | 
|  | } | 
|  | ss << '}'; | 
|  | return ss.str(); | 
|  | } | 
|  |  | 
|  | namespace { | 
|  | std::unique_ptr<voe::ChannelReceiveInterface> CreateChannelReceive( | 
|  | const Environment& env, | 
|  | AudioState* audio_state, | 
|  | NetEqFactory* neteq_factory, | 
|  | const AudioReceiveStreamInterface::Config& config) { | 
|  | RTC_DCHECK(audio_state); | 
|  | internal::AudioState* internal_audio_state = | 
|  | static_cast<internal::AudioState*>(audio_state); | 
|  | return voe::CreateChannelReceive( | 
|  | env, neteq_factory, internal_audio_state->audio_device_module(), | 
|  | config.rtcp_send_transport, config.rtp.local_ssrc, config.rtp.remote_ssrc, | 
|  | config.jitter_buffer_max_packets, config.jitter_buffer_fast_accelerate, | 
|  | config.jitter_buffer_min_delay_ms, config.enable_non_sender_rtt, | 
|  | config.decoder_factory, config.codec_pair_id, | 
|  | std::move(config.frame_decryptor), config.crypto_options, | 
|  | std::move(config.frame_transformer)); | 
|  | } | 
|  | }  // namespace | 
|  |  | 
|  | AudioReceiveStreamImpl::AudioReceiveStreamImpl( | 
|  | const Environment& env, | 
|  | PacketRouter* packet_router, | 
|  | NetEqFactory* neteq_factory, | 
|  | const AudioReceiveStreamInterface::Config& config, | 
|  | const scoped_refptr<AudioState>& audio_state) | 
|  | : AudioReceiveStreamImpl( | 
|  | env, | 
|  | packet_router, | 
|  | config, | 
|  | audio_state, | 
|  | CreateChannelReceive(env, audio_state.get(), neteq_factory, config)) { | 
|  | } | 
|  |  | 
|  | AudioReceiveStreamImpl::AudioReceiveStreamImpl( | 
|  | const Environment& /* env */, | 
|  | PacketRouter* packet_router, | 
|  | const AudioReceiveStreamInterface::Config& config, | 
|  | const scoped_refptr<AudioState>& audio_state, | 
|  | std::unique_ptr<voe::ChannelReceiveInterface> channel_receive) | 
|  | : config_(config), | 
|  | audio_state_(audio_state), | 
|  | channel_receive_(std::move(channel_receive)) { | 
|  | RTC_LOG(LS_INFO) << "AudioReceiveStreamImpl: " << config.rtp.remote_ssrc; | 
|  | RTC_DCHECK(config.decoder_factory); | 
|  | RTC_DCHECK(config.rtcp_send_transport); | 
|  | RTC_DCHECK(audio_state_); | 
|  | RTC_DCHECK(channel_receive_); | 
|  |  | 
|  | RTC_DCHECK(packet_router); | 
|  | // Configure bandwidth estimation. | 
|  | channel_receive_->RegisterReceiverCongestionControlObjects(packet_router); | 
|  |  | 
|  | // Complete configuration. | 
|  | // TODO(solenberg): Config NACK history window (which is a packet count), | 
|  | // using the actual packet size for the configured codec. | 
|  | channel_receive_->SetNACKStatus(config.rtp.nack.rtp_history_ms != 0, | 
|  | config.rtp.nack.rtp_history_ms / 20); | 
|  | channel_receive_->SetRtcpMode(config.rtp.rtcp_mode); | 
|  | channel_receive_->SetReceiveCodecs(config.decoder_map); | 
|  | // `frame_transformer` and `frame_decryptor` have been given to | 
|  | // `channel_receive_` already. | 
|  | } | 
|  |  | 
|  | AudioReceiveStreamImpl::~AudioReceiveStreamImpl() { | 
|  | RTC_DCHECK_RUN_ON(&worker_thread_checker_); | 
|  | RTC_LOG(LS_INFO) << "~AudioReceiveStreamImpl: " << remote_ssrc(); | 
|  | Stop(); | 
|  | channel_receive_->ResetReceiverCongestionControlObjects(); | 
|  | } | 
|  |  | 
|  | void AudioReceiveStreamImpl::RegisterWithTransport( | 
|  | RtpStreamReceiverControllerInterface* receiver_controller) { | 
|  | RTC_DCHECK_RUN_ON(&packet_sequence_checker_); | 
|  | RTC_DCHECK(!rtp_stream_receiver_); | 
|  | rtp_stream_receiver_ = receiver_controller->CreateReceiver( | 
|  | remote_ssrc(), channel_receive_.get()); | 
|  | } | 
|  |  | 
|  | void AudioReceiveStreamImpl::UnregisterFromTransport() { | 
|  | RTC_DCHECK_RUN_ON(&packet_sequence_checker_); | 
|  | rtp_stream_receiver_.reset(); | 
|  | } | 
|  |  | 
|  | void AudioReceiveStreamImpl::ReconfigureForTesting( | 
|  | const AudioReceiveStreamInterface::Config& config) { | 
|  | RTC_DCHECK_RUN_ON(&worker_thread_checker_); | 
|  |  | 
|  | // SSRC can't be changed mid-stream. | 
|  | RTC_DCHECK_EQ(remote_ssrc(), config.rtp.remote_ssrc); | 
|  | RTC_DCHECK_EQ(local_ssrc(), config.rtp.local_ssrc); | 
|  |  | 
|  | // Configuration parameters which cannot be changed. | 
|  | RTC_DCHECK_EQ(config_.rtcp_send_transport, config.rtcp_send_transport); | 
|  | // Decoder factory cannot be changed because it is configured at | 
|  | // voe::Channel construction time. | 
|  | RTC_DCHECK_EQ(config_.decoder_factory, config.decoder_factory); | 
|  |  | 
|  | // TODO(solenberg): Config NACK history window (which is a packet count), | 
|  | // using the actual packet size for the configured codec. | 
|  | RTC_DCHECK_EQ(config_.rtp.nack.rtp_history_ms, config.rtp.nack.rtp_history_ms) | 
|  | << "Use SetUseTransportCcAndNackHistory"; | 
|  |  | 
|  | RTC_DCHECK(config_.decoder_map == config.decoder_map) << "Use SetDecoderMap"; | 
|  | RTC_DCHECK_EQ(config_.frame_transformer, config.frame_transformer) | 
|  | << "Use SetDepacketizerToDecoderFrameTransformer"; | 
|  |  | 
|  | config_ = config; | 
|  | } | 
|  |  | 
|  | void AudioReceiveStreamImpl::Start() { | 
|  | RTC_DCHECK_RUN_ON(&worker_thread_checker_); | 
|  | if (playing_) { | 
|  | return; | 
|  | } | 
|  | RTC_LOG(LS_INFO) << "AudioReceiveStreamImpl::Start: " << remote_ssrc(); | 
|  | channel_receive_->StartPlayout(); | 
|  | playing_ = true; | 
|  | audio_state()->AddReceivingStream(this); | 
|  | } | 
|  |  | 
|  | void AudioReceiveStreamImpl::Stop() { | 
|  | RTC_DCHECK_RUN_ON(&worker_thread_checker_); | 
|  | if (!playing_) { | 
|  | return; | 
|  | } | 
|  | RTC_LOG(LS_INFO) << "AudioReceiveStreamImpl::Stop: " << remote_ssrc(); | 
|  | channel_receive_->StopPlayout(); | 
|  | playing_ = false; | 
|  | audio_state()->RemoveReceivingStream(this); | 
|  | } | 
|  |  | 
|  | bool AudioReceiveStreamImpl::IsRunning() const { | 
|  | RTC_DCHECK_RUN_ON(&worker_thread_checker_); | 
|  | return playing_; | 
|  | } | 
|  |  | 
|  | void AudioReceiveStreamImpl::SetDepacketizerToDecoderFrameTransformer( | 
|  | scoped_refptr<FrameTransformerInterface> frame_transformer) { | 
|  | RTC_DCHECK_RUN_ON(&worker_thread_checker_); | 
|  | channel_receive_->SetDepacketizerToDecoderFrameTransformer( | 
|  | std::move(frame_transformer)); | 
|  | } | 
|  |  | 
|  | void AudioReceiveStreamImpl::SetDecoderMap( | 
|  | std::map<int, SdpAudioFormat> decoder_map) { | 
|  | RTC_DCHECK_RUN_ON(&worker_thread_checker_); | 
|  | config_.decoder_map = std::move(decoder_map); | 
|  | channel_receive_->SetReceiveCodecs(config_.decoder_map); | 
|  | } | 
|  |  | 
|  | void AudioReceiveStreamImpl::SetNackHistory(int history_ms) { | 
|  | RTC_DCHECK_RUN_ON(&worker_thread_checker_); | 
|  | RTC_DCHECK_GE(history_ms, 0); | 
|  |  | 
|  | if (config_.rtp.nack.rtp_history_ms == history_ms) | 
|  | return; | 
|  |  | 
|  | config_.rtp.nack.rtp_history_ms = history_ms; | 
|  | // TODO(solenberg): Config NACK history window (which is a packet count), | 
|  | // using the actual packet size for the configured codec. | 
|  | channel_receive_->SetNACKStatus(history_ms != 0, history_ms / 20); | 
|  | } | 
|  |  | 
|  | void AudioReceiveStreamImpl::SetRtcpMode(RtcpMode mode) { | 
|  | RTC_DCHECK_RUN_ON(&worker_thread_checker_); | 
|  |  | 
|  | if (config_.rtp.rtcp_mode == mode) | 
|  | return; | 
|  |  | 
|  | config_.rtp.rtcp_mode = mode; | 
|  | channel_receive_->SetRtcpMode(mode); | 
|  | } | 
|  |  | 
|  | void AudioReceiveStreamImpl::SetNonSenderRttMeasurement(bool enabled) { | 
|  | RTC_DCHECK_RUN_ON(&worker_thread_checker_); | 
|  | config_.enable_non_sender_rtt = enabled; | 
|  | channel_receive_->SetNonSenderRttMeasurement(enabled); | 
|  | } | 
|  |  | 
|  | void AudioReceiveStreamImpl::SetFrameDecryptor( | 
|  | scoped_refptr<FrameDecryptorInterface> frame_decryptor) { | 
|  | // TODO(bugs.webrtc.org/11993): This is called via WebRtcAudioReceiveStream, | 
|  | // expect to be called on the network thread. | 
|  | RTC_DCHECK_RUN_ON(&worker_thread_checker_); | 
|  | channel_receive_->SetFrameDecryptor(std::move(frame_decryptor)); | 
|  | } | 
|  |  | 
|  | AudioReceiveStreamInterface::Stats AudioReceiveStreamImpl::GetStats( | 
|  | bool get_and_clear_legacy_stats) const { | 
|  | RTC_DCHECK_RUN_ON(&worker_thread_checker_); | 
|  | AudioReceiveStreamInterface::Stats stats; | 
|  | stats.remote_ssrc = remote_ssrc(); | 
|  |  | 
|  | auto receive_codec = channel_receive_->GetReceiveCodec(); | 
|  | if (receive_codec) { | 
|  | stats.codec_name = receive_codec->second.name; | 
|  | stats.codec_payload_type = receive_codec->first; | 
|  | } | 
|  |  | 
|  | CallReceiveStatistics call_stats = channel_receive_->GetRTCPStatistics(); | 
|  | stats.payload_bytes_received = call_stats.payload_bytes_received; | 
|  | stats.header_and_padding_bytes_received = | 
|  | call_stats.header_and_padding_bytes_received; | 
|  | stats.packets_received = call_stats.packets_received; | 
|  | stats.packets_lost = call_stats.packets_lost; | 
|  | stats.jitter_ms = call_stats.jitter_ms; | 
|  | stats.nacks_sent = call_stats.nacks_sent; | 
|  | stats.capture_start_ntp_time_ms = call_stats.capture_start_ntp_time_ms; | 
|  | stats.last_packet_received = call_stats.last_packet_received; | 
|  | stats.last_sender_report_timestamp = call_stats.last_sender_report_timestamp; | 
|  | stats.last_sender_report_utc_timestamp = | 
|  | call_stats.last_sender_report_utc_timestamp; | 
|  | stats.last_sender_report_remote_utc_timestamp = | 
|  | call_stats.last_sender_report_remote_utc_timestamp; | 
|  | stats.sender_reports_packets_sent = call_stats.sender_reports_packets_sent; | 
|  | stats.sender_reports_bytes_sent = call_stats.sender_reports_bytes_sent; | 
|  | stats.sender_reports_reports_count = call_stats.sender_reports_reports_count; | 
|  | stats.round_trip_time = call_stats.round_trip_time; | 
|  | stats.round_trip_time_measurements = call_stats.round_trip_time_measurements; | 
|  | stats.total_round_trip_time = call_stats.total_round_trip_time; | 
|  |  | 
|  | stats.delay_estimate_ms = channel_receive_->GetDelayEstimate(); | 
|  | stats.audio_level = channel_receive_->GetSpeechOutputLevelFullRange(); | 
|  | stats.total_output_energy = channel_receive_->GetTotalOutputEnergy(); | 
|  | stats.total_output_duration = channel_receive_->GetTotalOutputDuration(); | 
|  | stats.estimated_playout_ntp_timestamp_ms = | 
|  | channel_receive_->GetCurrentEstimatedPlayoutNtpTimestampMs(TimeMillis()); | 
|  |  | 
|  | // Get jitter buffer and total delay (alg + jitter + playout) stats. | 
|  | auto ns = channel_receive_->GetNetworkStatistics(get_and_clear_legacy_stats); | 
|  | stats.packets_discarded = ns.packetsDiscarded; | 
|  | stats.fec_packets_received = ns.fecPacketsReceived; | 
|  | stats.fec_packets_discarded = ns.fecPacketsDiscarded; | 
|  | stats.jitter_buffer_ms = ns.currentBufferSize; | 
|  | stats.jitter_buffer_preferred_ms = ns.preferredBufferSize; | 
|  | stats.total_samples_received = ns.totalSamplesReceived; | 
|  | stats.concealed_samples = ns.concealedSamples; | 
|  | stats.silent_concealed_samples = ns.silentConcealedSamples; | 
|  | stats.concealment_events = ns.concealmentEvents; | 
|  | stats.jitter_buffer_delay_seconds = | 
|  | static_cast<double>(ns.jitterBufferDelayMs) / | 
|  | static_cast<double>(kNumMillisecsPerSec); | 
|  | stats.jitter_buffer_emitted_count = ns.jitterBufferEmittedCount; | 
|  | stats.jitter_buffer_target_delay_seconds = | 
|  | static_cast<double>(ns.jitterBufferTargetDelayMs) / | 
|  | static_cast<double>(kNumMillisecsPerSec); | 
|  | stats.jitter_buffer_minimum_delay_seconds = | 
|  | static_cast<double>(ns.jitterBufferMinimumDelayMs) / | 
|  | static_cast<double>(kNumMillisecsPerSec); | 
|  | stats.inserted_samples_for_deceleration = ns.insertedSamplesForDeceleration; | 
|  | stats.removed_samples_for_acceleration = ns.removedSamplesForAcceleration; | 
|  | stats.total_processing_delay_seconds = | 
|  | static_cast<double>(ns.totalProcessingDelayUs) / | 
|  | static_cast<double>(kNumMicrosecsPerSec); | 
|  | stats.expand_rate = Q14ToFloat(ns.currentExpandRate); | 
|  | stats.speech_expand_rate = Q14ToFloat(ns.currentSpeechExpandRate); | 
|  | stats.secondary_decoded_rate = Q14ToFloat(ns.currentSecondaryDecodedRate); | 
|  | stats.secondary_discarded_rate = Q14ToFloat(ns.currentSecondaryDiscardedRate); | 
|  | stats.accelerate_rate = Q14ToFloat(ns.currentAccelerateRate); | 
|  | stats.preemptive_expand_rate = Q14ToFloat(ns.currentPreemptiveRate); | 
|  | stats.jitter_buffer_flushes = ns.packetBufferFlushes; | 
|  | stats.delayed_packet_outage_samples = ns.delayedPacketOutageSamples; | 
|  | stats.relative_packet_arrival_delay_seconds = | 
|  | static_cast<double>(ns.relativePacketArrivalDelayMs) / | 
|  | static_cast<double>(kNumMillisecsPerSec); | 
|  | stats.interruption_count = ns.interruptionCount; | 
|  | stats.total_interruption_duration_ms = ns.totalInterruptionDurationMs; | 
|  |  | 
|  | auto ds = channel_receive_->GetDecodingCallStatistics(); | 
|  | stats.decoding_calls_to_silence_generator = ds.calls_to_silence_generator; | 
|  | stats.decoding_calls_to_neteq = ds.calls_to_neteq; | 
|  | stats.decoding_normal = ds.decoded_normal; | 
|  | stats.decoding_plc = ds.decoded_neteq_plc; | 
|  | stats.decoding_codec_plc = ds.decoded_codec_plc; | 
|  | stats.decoding_cng = ds.decoded_cng; | 
|  | stats.decoding_plc_cng = ds.decoded_plc_cng; | 
|  | stats.decoding_muted_output = ds.decoded_muted_output; | 
|  |  | 
|  | return stats; | 
|  | } | 
|  |  | 
|  | void AudioReceiveStreamImpl::SetSink(AudioSinkInterface* sink) { | 
|  | RTC_DCHECK_RUN_ON(&worker_thread_checker_); | 
|  | channel_receive_->SetSink(sink); | 
|  | } | 
|  |  | 
|  | void AudioReceiveStreamImpl::SetGain(float gain) { | 
|  | RTC_DCHECK_RUN_ON(&worker_thread_checker_); | 
|  | channel_receive_->SetChannelOutputVolumeScaling(gain); | 
|  | } | 
|  |  | 
|  | bool AudioReceiveStreamImpl::SetBaseMinimumPlayoutDelayMs(int delay_ms) { | 
|  | RTC_DCHECK_RUN_ON(&worker_thread_checker_); | 
|  | return channel_receive_->SetBaseMinimumPlayoutDelayMs(delay_ms); | 
|  | } | 
|  |  | 
|  | int AudioReceiveStreamImpl::GetBaseMinimumPlayoutDelayMs() const { | 
|  | RTC_DCHECK_RUN_ON(&worker_thread_checker_); | 
|  | return channel_receive_->GetBaseMinimumPlayoutDelayMs(); | 
|  | } | 
|  |  | 
|  | std::vector<RtpSource> AudioReceiveStreamImpl::GetSources() const { | 
|  | RTC_DCHECK_RUN_ON(&worker_thread_checker_); | 
|  | return channel_receive_->GetSources(); | 
|  | } | 
|  |  | 
|  | AudioMixer::Source::AudioFrameInfo | 
|  | AudioReceiveStreamImpl::GetAudioFrameWithInfo(int sample_rate_hz, | 
|  | AudioFrame* audio_frame) { | 
|  | return channel_receive_->GetAudioFrameWithInfo(sample_rate_hz, audio_frame); | 
|  | } | 
|  |  | 
|  | int AudioReceiveStreamImpl::Ssrc() const { | 
|  | return remote_ssrc(); | 
|  | } | 
|  |  | 
|  | int AudioReceiveStreamImpl::PreferredSampleRate() const { | 
|  | return channel_receive_->PreferredSampleRate(); | 
|  | } | 
|  |  | 
|  | uint32_t AudioReceiveStreamImpl::id() const { | 
|  | RTC_DCHECK_RUN_ON(&worker_thread_checker_); | 
|  | return remote_ssrc(); | 
|  | } | 
|  |  | 
|  | std::optional<Syncable::Info> AudioReceiveStreamImpl::GetInfo() const { | 
|  | // TODO(bugs.webrtc.org/11993): This is called via RtpStreamsSynchronizer, | 
|  | // expect to be called on the network thread. | 
|  | RTC_DCHECK_RUN_ON(&worker_thread_checker_); | 
|  | return channel_receive_->GetSyncInfo(); | 
|  | } | 
|  |  | 
|  | bool AudioReceiveStreamImpl::GetPlayoutRtpTimestamp(uint32_t* rtp_timestamp, | 
|  | int64_t* time_ms) const { | 
|  | // Called on video capture thread. | 
|  | return channel_receive_->GetPlayoutRtpTimestamp(rtp_timestamp, time_ms); | 
|  | } | 
|  |  | 
|  | void AudioReceiveStreamImpl::SetEstimatedPlayoutNtpTimestampMs( | 
|  | int64_t ntp_timestamp_ms, | 
|  | int64_t time_ms) { | 
|  | // Called on video capture thread. | 
|  | channel_receive_->SetEstimatedPlayoutNtpTimestampMs(ntp_timestamp_ms, | 
|  | time_ms); | 
|  | } | 
|  |  | 
|  | bool AudioReceiveStreamImpl::SetMinimumPlayoutDelay(int delay_ms) { | 
|  | // TODO(bugs.webrtc.org/11993): This is called via RtpStreamsSynchronizer, | 
|  | // expect to be called on the network thread. | 
|  | RTC_DCHECK_RUN_ON(&worker_thread_checker_); | 
|  | return channel_receive_->SetMinimumPlayoutDelay(delay_ms); | 
|  | } | 
|  |  | 
|  | void AudioReceiveStreamImpl::DeliverRtcp(const uint8_t* packet, size_t length) { | 
|  | RTC_DCHECK_RUN_ON(&worker_thread_checker_); | 
|  | channel_receive_->ReceivedRTCPPacket(packet, length); | 
|  | } | 
|  |  | 
|  | void AudioReceiveStreamImpl::SetSyncGroup(absl::string_view sync_group) { | 
|  | RTC_DCHECK_RUN_ON(&packet_sequence_checker_); | 
|  | config_.sync_group = std::string(sync_group); | 
|  | } | 
|  |  | 
|  | void AudioReceiveStreamImpl::SetLocalSsrc(uint32_t local_ssrc) { | 
|  | RTC_DCHECK_RUN_ON(&packet_sequence_checker_); | 
|  | // TODO(tommi): Consider storing local_ssrc in one place. | 
|  | config_.rtp.local_ssrc = local_ssrc; | 
|  | channel_receive_->OnLocalSsrcChange(local_ssrc); | 
|  | } | 
|  |  | 
|  | uint32_t AudioReceiveStreamImpl::local_ssrc() const { | 
|  | RTC_DCHECK_RUN_ON(&packet_sequence_checker_); | 
|  | return config_.rtp.local_ssrc; | 
|  | } | 
|  |  | 
|  | const std::string& AudioReceiveStreamImpl::sync_group() const { | 
|  | RTC_DCHECK_RUN_ON(&packet_sequence_checker_); | 
|  | return config_.sync_group; | 
|  | } | 
|  |  | 
|  | internal::AudioState* AudioReceiveStreamImpl::audio_state() const { | 
|  | auto* audio_state = static_cast<internal::AudioState*>(audio_state_.get()); | 
|  | RTC_DCHECK(audio_state); | 
|  | return audio_state; | 
|  | } | 
|  | }  // namespace webrtc |