modules/audio_coding/codecs/cng/audio_encoder_cng.cc - src - Git at Google

 /*
  *  Copyright (c) 2014 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 "modules/audio_coding/codecs/cng/audio_encoder_cng.h"

 #include <cstdint>
 #include <memory>
 #include <utility>

 #include "modules/audio_coding/codecs/cng/webrtc_cng.h"
 #include "rtc_base/checks.h"

 namespace webrtc {

 namespace {

 const int kMaxFrameSizeMs = 60;

 class AudioEncoderCng final : public AudioEncoder {
  public:
   explicit AudioEncoderCng(AudioEncoderCngConfig&& config);
   ~AudioEncoderCng() override;

   // Not copyable or moveable.
   AudioEncoderCng(const AudioEncoderCng&) = delete;
   AudioEncoderCng(AudioEncoderCng&&) = delete;
   AudioEncoderCng& operator=(const AudioEncoderCng&) = delete;
   AudioEncoderCng& operator=(AudioEncoderCng&&) = delete;

   int SampleRateHz() const override;
   size_t NumChannels() const override;
   int RtpTimestampRateHz() const override;
   size_t Num10MsFramesInNextPacket() const override;
   size_t Max10MsFramesInAPacket() const override;
   int GetTargetBitrate() const override;
   EncodedInfo EncodeImpl(uint32_t rtp_timestamp,
                          rtc::ArrayView<const int16_t> audio,
                          rtc::Buffer* encoded) override;
   void Reset() override;
   bool SetFec(bool enable) override;
   bool SetDtx(bool enable) override;
   bool SetApplication(Application application) override;
   void SetMaxPlaybackRate(int frequency_hz) override;
   rtc::ArrayView<std::unique_ptr<AudioEncoder>> ReclaimContainedEncoders()
       override;
   void OnReceivedUplinkPacketLossFraction(
       float uplink_packet_loss_fraction) override;
   void OnReceivedUplinkBandwidth(
       int target_audio_bitrate_bps,
       absl::optional<int64_t> bwe_period_ms) override;

  private:
   EncodedInfo EncodePassive(size_t frames_to_encode, rtc::Buffer* encoded);
   EncodedInfo EncodeActive(size_t frames_to_encode, rtc::Buffer* encoded);
   size_t SamplesPer10msFrame() const;

   std::unique_ptr<AudioEncoder> speech_encoder_;
   const int cng_payload_type_;
   const int num_cng_coefficients_;
   const int sid_frame_interval_ms_;
   std::vector<int16_t> speech_buffer_;
   std::vector<uint32_t> rtp_timestamps_;
   bool last_frame_active_;
   std::unique_ptr<Vad> vad_;
   std::unique_ptr<ComfortNoiseEncoder> cng_encoder_;
 };

 AudioEncoderCng::AudioEncoderCng(AudioEncoderCngConfig&& config)
     : speech_encoder_((static_cast<void>([&] {
                          RTC_CHECK(config.IsOk()) << "Invalid configuration.";
                        }()),
                        std::move(config.speech_encoder))),
       cng_payload_type_(config.payload_type),
       num_cng_coefficients_(config.num_cng_coefficients),
       sid_frame_interval_ms_(config.sid_frame_interval_ms),
       last_frame_active_(true),
       vad_(config.vad ? std::unique_ptr<Vad>(config.vad)
                       : CreateVad(config.vad_mode)),
       cng_encoder_(new ComfortNoiseEncoder(SampleRateHz(),
                                            sid_frame_interval_ms_,
                                            num_cng_coefficients_)) {}

 AudioEncoderCng::~AudioEncoderCng() = default;

 int AudioEncoderCng::SampleRateHz() const {
   return speech_encoder_->SampleRateHz();
 }

 size_t AudioEncoderCng::NumChannels() const {
   return 1;
 }

 int AudioEncoderCng::RtpTimestampRateHz() const {
   return speech_encoder_->RtpTimestampRateHz();
 }

 size_t AudioEncoderCng::Num10MsFramesInNextPacket() const {
   return speech_encoder_->Num10MsFramesInNextPacket();
 }

 size_t AudioEncoderCng::Max10MsFramesInAPacket() const {
   return speech_encoder_->Max10MsFramesInAPacket();
 }

 int AudioEncoderCng::GetTargetBitrate() const {
   return speech_encoder_->GetTargetBitrate();
 }

 AudioEncoder::EncodedInfo AudioEncoderCng::EncodeImpl(
     uint32_t rtp_timestamp,
     rtc::ArrayView<const int16_t> audio,
     rtc::Buffer* encoded) {
   const size_t samples_per_10ms_frame = SamplesPer10msFrame();
   RTC_CHECK_EQ(speech_buffer_.size(),
                rtp_timestamps_.size() * samples_per_10ms_frame);
   rtp_timestamps_.push_back(rtp_timestamp);
   RTC_DCHECK_EQ(samples_per_10ms_frame, audio.size());
   speech_buffer_.insert(speech_buffer_.end(), audio.cbegin(), audio.cend());
   const size_t frames_to_encode = speech_encoder_->Num10MsFramesInNextPacket();
   if (rtp_timestamps_.size() < frames_to_encode) {
     return EncodedInfo();
   }
   RTC_CHECK_LE(frames_to_encode * 10, kMaxFrameSizeMs)
       << "Frame size cannot be larger than " << kMaxFrameSizeMs
       << " ms when using VAD/CNG.";

   // Group several 10 ms blocks per VAD call. Call VAD once or twice using the
   // following split sizes:
   // 10 ms = 10 + 0 ms; 20 ms = 20 + 0 ms; 30 ms = 30 + 0 ms;
   // 40 ms = 20 + 20 ms; 50 ms = 30 + 20 ms; 60 ms = 30 + 30 ms.
   size_t blocks_in_first_vad_call =
       (frames_to_encode > 3 ? 3 : frames_to_encode);
   if (frames_to_encode == 4)
     blocks_in_first_vad_call = 2;
   RTC_CHECK_GE(frames_to_encode, blocks_in_first_vad_call);
   const size_t blocks_in_second_vad_call =
       frames_to_encode - blocks_in_first_vad_call;

   // Check if all of the buffer is passive speech. Start with checking the first
   // block.
   Vad::Activity activity = vad_->VoiceActivity(
       &speech_buffer_[0], samples_per_10ms_frame * blocks_in_first_vad_call,
       SampleRateHz());
   if (activity == Vad::kPassive && blocks_in_second_vad_call > 0) {
     // Only check the second block if the first was passive.
     activity = vad_->VoiceActivity(
         &speech_buffer_[samples_per_10ms_frame * blocks_in_first_vad_call],
         samples_per_10ms_frame * blocks_in_second_vad_call, SampleRateHz());
   }

   EncodedInfo info;
   switch (activity) {
     case Vad::kPassive: {
       info = EncodePassive(frames_to_encode, encoded);
       last_frame_active_ = false;
       break;
     }
     case Vad::kActive: {
       info = EncodeActive(frames_to_encode, encoded);
       last_frame_active_ = true;
       break;
     }
     case Vad::kError: {
       FATAL();  // Fails only if fed invalid data.
       break;
     }
   }

   speech_buffer_.erase(
       speech_buffer_.begin(),
       speech_buffer_.begin() + frames_to_encode * samples_per_10ms_frame);
   rtp_timestamps_.erase(rtp_timestamps_.begin(),
                         rtp_timestamps_.begin() + frames_to_encode);
   return info;
 }

 void AudioEncoderCng::Reset() {
   speech_encoder_->Reset();
   speech_buffer_.clear();
   rtp_timestamps_.clear();
   last_frame_active_ = true;
   vad_->Reset();
   cng_encoder_.reset(new ComfortNoiseEncoder(
       SampleRateHz(), sid_frame_interval_ms_, num_cng_coefficients_));
 }

 bool AudioEncoderCng::SetFec(bool enable) {
   return speech_encoder_->SetFec(enable);
 }

 bool AudioEncoderCng::SetDtx(bool enable) {
   return speech_encoder_->SetDtx(enable);
 }

 bool AudioEncoderCng::SetApplication(Application application) {
   return speech_encoder_->SetApplication(application);
 }

 void AudioEncoderCng::SetMaxPlaybackRate(int frequency_hz) {
   speech_encoder_->SetMaxPlaybackRate(frequency_hz);
 }

 rtc::ArrayView<std::unique_ptr<AudioEncoder>>
 AudioEncoderCng::ReclaimContainedEncoders() {
   return rtc::ArrayView<std::unique_ptr<AudioEncoder>>(&speech_encoder_, 1);
 }

 void AudioEncoderCng::OnReceivedUplinkPacketLossFraction(
     float uplink_packet_loss_fraction) {
   speech_encoder_->OnReceivedUplinkPacketLossFraction(
       uplink_packet_loss_fraction);
 }

 void AudioEncoderCng::OnReceivedUplinkBandwidth(
     int target_audio_bitrate_bps,
     absl::optional<int64_t> bwe_period_ms) {
   speech_encoder_->OnReceivedUplinkBandwidth(target_audio_bitrate_bps,
                                              bwe_period_ms);
 }

 AudioEncoder::EncodedInfo AudioEncoderCng::EncodePassive(
     size_t frames_to_encode,
     rtc::Buffer* encoded) {
   bool force_sid = last_frame_active_;
   bool output_produced = false;
   const size_t samples_per_10ms_frame = SamplesPer10msFrame();
   AudioEncoder::EncodedInfo info;

   for (size_t i = 0; i < frames_to_encode; ++i) {
     // It's important not to pass &info.encoded_bytes directly to
     // WebRtcCng_Encode(), since later loop iterations may return zero in
     // that value, in which case we don't want to overwrite any value from
     // an earlier iteration.
     size_t encoded_bytes_tmp =
         cng_encoder_->Encode(rtc::ArrayView<const int16_t>(
                                  &speech_buffer_[i * samples_per_10ms_frame],
                                  samples_per_10ms_frame),
                              force_sid, encoded);

     if (encoded_bytes_tmp > 0) {
       RTC_CHECK(!output_produced);
       info.encoded_bytes = encoded_bytes_tmp;
       output_produced = true;
       force_sid = false;
     }
   }

   info.encoded_timestamp = rtp_timestamps_.front();
   info.payload_type = cng_payload_type_;
   info.send_even_if_empty = true;
   info.speech = false;
   return info;
 }

 AudioEncoder::EncodedInfo AudioEncoderCng::EncodeActive(size_t frames_to_encode,
                                                         rtc::Buffer* encoded) {
   const size_t samples_per_10ms_frame = SamplesPer10msFrame();
   AudioEncoder::EncodedInfo info;
   for (size_t i = 0; i < frames_to_encode; ++i) {
     info =
         speech_encoder_->Encode(rtp_timestamps_.front(),
                                 rtc::ArrayView<const int16_t>(
                                     &speech_buffer_[i * samples_per_10ms_frame],
                                     samples_per_10ms_frame),
                                 encoded);
     if (i + 1 == frames_to_encode) {
       RTC_CHECK_GT(info.encoded_bytes, 0) << "Encoder didn't deliver data.";
     } else {
       RTC_CHECK_EQ(info.encoded_bytes, 0)
           << "Encoder delivered data too early.";
     }
   }
   return info;
 }

 size_t AudioEncoderCng::SamplesPer10msFrame() const {
   return rtc::CheckedDivExact(10 * SampleRateHz(), 1000);
 }

 }  // namespace

 AudioEncoderCngConfig::AudioEncoderCngConfig() = default;
 AudioEncoderCngConfig::AudioEncoderCngConfig(AudioEncoderCngConfig&&) = default;
 AudioEncoderCngConfig::~AudioEncoderCngConfig() = default;

 bool AudioEncoderCngConfig::IsOk() const {
   if (num_channels != 1)
     return false;
   if (!speech_encoder)
     return false;
   if (num_channels != speech_encoder->NumChannels())
     return false;
   if (sid_frame_interval_ms <
       static_cast<int>(speech_encoder->Max10MsFramesInAPacket() * 10))
     return false;
   if (num_cng_coefficients > WEBRTC_CNG_MAX_LPC_ORDER ||
       num_cng_coefficients <= 0)
     return false;
   return true;
 }

 std::unique_ptr<AudioEncoder> CreateComfortNoiseEncoder(
     AudioEncoderCngConfig&& config) {
   return std::make_unique<AudioEncoderCng>(std::move(config));
 }

 }  // namespace webrtc
	/*
	* Copyright (c) 2014 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 "modules/audio_coding/codecs/cng/audio_encoder_cng.h"

	#include <cstdint>
	#include <memory>
	#include <utility>

	#include "modules/audio_coding/codecs/cng/webrtc_cng.h"
	#include "rtc_base/checks.h"

	namespace webrtc {

	namespace {

	const int kMaxFrameSizeMs = 60;

	class AudioEncoderCng final : public AudioEncoder {
	public:
	explicit AudioEncoderCng(AudioEncoderCngConfig&& config);
	~AudioEncoderCng() override;

	// Not copyable or moveable.
	AudioEncoderCng(const AudioEncoderCng&) = delete;
	AudioEncoderCng(AudioEncoderCng&&) = delete;
	AudioEncoderCng& operator=(const AudioEncoderCng&) = delete;
	AudioEncoderCng& operator=(AudioEncoderCng&&) = delete;

	int SampleRateHz() const override;
	size_t NumChannels() const override;
	int RtpTimestampRateHz() const override;
	size_t Num10MsFramesInNextPacket() const override;
	size_t Max10MsFramesInAPacket() const override;
	int GetTargetBitrate() const override;
	EncodedInfo EncodeImpl(uint32_t rtp_timestamp,
	rtc::ArrayView<const int16_t> audio,
	rtc::Buffer* encoded) override;
	void Reset() override;
	bool SetFec(bool enable) override;
	bool SetDtx(bool enable) override;
	bool SetApplication(Application application) override;
	void SetMaxPlaybackRate(int frequency_hz) override;
	rtc::ArrayView<std::unique_ptr<AudioEncoder>> ReclaimContainedEncoders()
	override;
	void OnReceivedUplinkPacketLossFraction(
	float uplink_packet_loss_fraction) override;
	void OnReceivedUplinkBandwidth(
	int target_audio_bitrate_bps,
	absl::optional<int64_t> bwe_period_ms) override;

	private:
	EncodedInfo EncodePassive(size_t frames_to_encode, rtc::Buffer* encoded);
	EncodedInfo EncodeActive(size_t frames_to_encode, rtc::Buffer* encoded);
	size_t SamplesPer10msFrame() const;

	std::unique_ptr<AudioEncoder> speech_encoder_;
	const int cng_payload_type_;
	const int num_cng_coefficients_;
	const int sid_frame_interval_ms_;
	std::vector<int16_t> speech_buffer_;
	std::vector<uint32_t> rtp_timestamps_;
	bool last_frame_active_;
	std::unique_ptr<Vad> vad_;
	std::unique_ptr<ComfortNoiseEncoder> cng_encoder_;
	};

	AudioEncoderCng::AudioEncoderCng(AudioEncoderCngConfig&& config)
	: speech_encoder_((static_cast<void>([&] {
	RTC_CHECK(config.IsOk()) << "Invalid configuration.";
	}()),
	std::move(config.speech_encoder))),
	cng_payload_type_(config.payload_type),
	num_cng_coefficients_(config.num_cng_coefficients),
	sid_frame_interval_ms_(config.sid_frame_interval_ms),
	last_frame_active_(true),
	vad_(config.vad ? std::unique_ptr<Vad>(config.vad)
	: CreateVad(config.vad_mode)),
	cng_encoder_(new ComfortNoiseEncoder(SampleRateHz(),
	sid_frame_interval_ms_,
	num_cng_coefficients_)) {}

	AudioEncoderCng::~AudioEncoderCng() = default;

	int AudioEncoderCng::SampleRateHz() const {
	return speech_encoder_->SampleRateHz();
	}

	size_t AudioEncoderCng::NumChannels() const {
	return 1;
	}

	int AudioEncoderCng::RtpTimestampRateHz() const {
	return speech_encoder_->RtpTimestampRateHz();
	}

	size_t AudioEncoderCng::Num10MsFramesInNextPacket() const {
	return speech_encoder_->Num10MsFramesInNextPacket();
	}

	size_t AudioEncoderCng::Max10MsFramesInAPacket() const {
	return speech_encoder_->Max10MsFramesInAPacket();
	}

	int AudioEncoderCng::GetTargetBitrate() const {
	return speech_encoder_->GetTargetBitrate();
	}

	AudioEncoder::EncodedInfo AudioEncoderCng::EncodeImpl(
	uint32_t rtp_timestamp,
	rtc::ArrayView<const int16_t> audio,
	rtc::Buffer* encoded) {
	const size_t samples_per_10ms_frame = SamplesPer10msFrame();
	RTC_CHECK_EQ(speech_buffer_.size(),
	rtp_timestamps_.size() * samples_per_10ms_frame);
	rtp_timestamps_.push_back(rtp_timestamp);
	RTC_DCHECK_EQ(samples_per_10ms_frame, audio.size());
	speech_buffer_.insert(speech_buffer_.end(), audio.cbegin(), audio.cend());
	const size_t frames_to_encode = speech_encoder_->Num10MsFramesInNextPacket();
	if (rtp_timestamps_.size() < frames_to_encode) {
	return EncodedInfo();
	}
	RTC_CHECK_LE(frames_to_encode * 10, kMaxFrameSizeMs)
	<< "Frame size cannot be larger than " << kMaxFrameSizeMs
	<< " ms when using VAD/CNG.";

	// Group several 10 ms blocks per VAD call. Call VAD once or twice using the
	// following split sizes:
	// 10 ms = 10 + 0 ms; 20 ms = 20 + 0 ms; 30 ms = 30 + 0 ms;
	// 40 ms = 20 + 20 ms; 50 ms = 30 + 20 ms; 60 ms = 30 + 30 ms.
	size_t blocks_in_first_vad_call =
	(frames_to_encode > 3 ? 3 : frames_to_encode);
	if (frames_to_encode == 4)
	blocks_in_first_vad_call = 2;
	RTC_CHECK_GE(frames_to_encode, blocks_in_first_vad_call);
	const size_t blocks_in_second_vad_call =
	frames_to_encode - blocks_in_first_vad_call;

	// Check if all of the buffer is passive speech. Start with checking the first
	// block.
	Vad::Activity activity = vad_->VoiceActivity(
	&speech_buffer_[0], samples_per_10ms_frame * blocks_in_first_vad_call,
	SampleRateHz());
	if (activity == Vad::kPassive && blocks_in_second_vad_call > 0) {
	// Only check the second block if the first was passive.
	activity = vad_->VoiceActivity(
	&speech_buffer_[samples_per_10ms_frame * blocks_in_first_vad_call],
	samples_per_10ms_frame * blocks_in_second_vad_call, SampleRateHz());
	}

	EncodedInfo info;
	switch (activity) {
	case Vad::kPassive: {
	info = EncodePassive(frames_to_encode, encoded);
	last_frame_active_ = false;
	break;
	}
	case Vad::kActive: {
	info = EncodeActive(frames_to_encode, encoded);
	last_frame_active_ = true;
	break;
	}
	case Vad::kError: {
	FATAL(); // Fails only if fed invalid data.
	break;
	}
	}

	speech_buffer_.erase(
	speech_buffer_.begin(),
	speech_buffer_.begin() + frames_to_encode * samples_per_10ms_frame);
	rtp_timestamps_.erase(rtp_timestamps_.begin(),
	rtp_timestamps_.begin() + frames_to_encode);
	return info;
	}

	void AudioEncoderCng::Reset() {
	speech_encoder_->Reset();
	speech_buffer_.clear();
	rtp_timestamps_.clear();
	last_frame_active_ = true;
	vad_->Reset();
	cng_encoder_.reset(new ComfortNoiseEncoder(
	SampleRateHz(), sid_frame_interval_ms_, num_cng_coefficients_));
	}

	bool AudioEncoderCng::SetFec(bool enable) {
	return speech_encoder_->SetFec(enable);
	}

	bool AudioEncoderCng::SetDtx(bool enable) {
	return speech_encoder_->SetDtx(enable);
	}

	bool AudioEncoderCng::SetApplication(Application application) {
	return speech_encoder_->SetApplication(application);
	}

	void AudioEncoderCng::SetMaxPlaybackRate(int frequency_hz) {
	speech_encoder_->SetMaxPlaybackRate(frequency_hz);
	}

	rtc::ArrayView<std::unique_ptr<AudioEncoder>>
	AudioEncoderCng::ReclaimContainedEncoders() {
	return rtc::ArrayView<std::unique_ptr<AudioEncoder>>(&speech_encoder_, 1);
	}

	void AudioEncoderCng::OnReceivedUplinkPacketLossFraction(
	float uplink_packet_loss_fraction) {
	speech_encoder_->OnReceivedUplinkPacketLossFraction(
	uplink_packet_loss_fraction);
	}

	void AudioEncoderCng::OnReceivedUplinkBandwidth(
	int target_audio_bitrate_bps,
	absl::optional<int64_t> bwe_period_ms) {
	speech_encoder_->OnReceivedUplinkBandwidth(target_audio_bitrate_bps,
	bwe_period_ms);
	}

	AudioEncoder::EncodedInfo AudioEncoderCng::EncodePassive(
	size_t frames_to_encode,
	rtc::Buffer* encoded) {
	bool force_sid = last_frame_active_;
	bool output_produced = false;
	const size_t samples_per_10ms_frame = SamplesPer10msFrame();
	AudioEncoder::EncodedInfo info;

	for (size_t i = 0; i < frames_to_encode; ++i) {
	// It's important not to pass &info.encoded_bytes directly to
	// WebRtcCng_Encode(), since later loop iterations may return zero in
	// that value, in which case we don't want to overwrite any value from
	// an earlier iteration.
	size_t encoded_bytes_tmp =
	cng_encoder_->Encode(rtc::ArrayView<const int16_t>(
	&speech_buffer_[i * samples_per_10ms_frame],
	samples_per_10ms_frame),
	force_sid, encoded);

	if (encoded_bytes_tmp > 0) {
	RTC_CHECK(!output_produced);
	info.encoded_bytes = encoded_bytes_tmp;
	output_produced = true;
	force_sid = false;
	}
	}

	info.encoded_timestamp = rtp_timestamps_.front();
	info.payload_type = cng_payload_type_;
	info.send_even_if_empty = true;
	info.speech = false;
	return info;
	}

	AudioEncoder::EncodedInfo AudioEncoderCng::EncodeActive(size_t frames_to_encode,
	rtc::Buffer* encoded) {
	const size_t samples_per_10ms_frame = SamplesPer10msFrame();
	AudioEncoder::EncodedInfo info;
	for (size_t i = 0; i < frames_to_encode; ++i) {
	info =
	speech_encoder_->Encode(rtp_timestamps_.front(),
	rtc::ArrayView<const int16_t>(
	&speech_buffer_[i * samples_per_10ms_frame],
	samples_per_10ms_frame),
	encoded);
	if (i + 1 == frames_to_encode) {
	RTC_CHECK_GT(info.encoded_bytes, 0) << "Encoder didn't deliver data.";
	} else {
	RTC_CHECK_EQ(info.encoded_bytes, 0)
	<< "Encoder delivered data too early.";
	}
	}
	return info;
	}

	size_t AudioEncoderCng::SamplesPer10msFrame() const {
	return rtc::CheckedDivExact(10 * SampleRateHz(), 1000);
	}

	} // namespace

	AudioEncoderCngConfig::AudioEncoderCngConfig() = default;
	AudioEncoderCngConfig::AudioEncoderCngConfig(AudioEncoderCngConfig&&) = default;
	AudioEncoderCngConfig::~AudioEncoderCngConfig() = default;

	bool AudioEncoderCngConfig::IsOk() const {
	if (num_channels != 1)
	return false;
	if (!speech_encoder)
	return false;
	if (num_channels != speech_encoder->NumChannels())
	return false;
	if (sid_frame_interval_ms <
	static_cast<int>(speech_encoder->Max10MsFramesInAPacket() * 10))
	return false;
	if (num_cng_coefficients > WEBRTC_CNG_MAX_LPC_ORDER \|\|
	num_cng_coefficients <= 0)
	return false;
	return true;
	}

	std::unique_ptr<AudioEncoder> CreateComfortNoiseEncoder(
	AudioEncoderCngConfig&& config) {
	return std::make_unique<AudioEncoderCng>(std::move(config));
	}

	} // namespace webrtc