modules/audio_mixer/frame_combiner.cc - src - Git at Google

 /*
  *  Copyright (c) 2017 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_mixer/frame_combiner.h"

 #include <algorithm>
 #include <array>
 #include <cstdint>
 #include <iterator>
 #include <string>

 #include "absl/memory/memory.h"
 #include "api/array_view.h"
 #include "common_audio/include/audio_util.h"
 #include "modules/audio_mixer/audio_frame_manipulator.h"
 #include "modules/audio_mixer/audio_mixer_impl.h"
 #include "modules/audio_processing/include/audio_frame_view.h"
 #include "modules/audio_processing/include/audio_processing.h"
 #include "modules/audio_processing/logging/apm_data_dumper.h"
 #include "rtc_base/arraysize.h"
 #include "rtc_base/checks.h"
 #include "system_wrappers/include/metrics.h"

 namespace webrtc {
 namespace {

 using MixingBuffer =
     std::array<std::array<float, FrameCombiner::kMaximumChannelSize>,
                FrameCombiner::kMaximumNumberOfChannels>;

 void SetAudioFrameFields(const std::vector<AudioFrame*>& mix_list,
                          size_t number_of_channels,
                          int sample_rate,
                          size_t number_of_streams,
                          AudioFrame* audio_frame_for_mixing) {
   const size_t samples_per_channel = static_cast<size_t>(
       (sample_rate * webrtc::AudioMixerImpl::kFrameDurationInMs) / 1000);

   // TODO(minyue): Issue bugs.webrtc.org/3390.
   // Audio frame timestamp. The 'timestamp_' field is set to dummy
   // value '0', because it is only supported in the one channel case and
   // is then updated in the helper functions.
   audio_frame_for_mixing->UpdateFrame(
       0, nullptr, samples_per_channel, sample_rate, AudioFrame::kUndefined,
       AudioFrame::kVadUnknown, number_of_channels);

   if (mix_list.empty()) {
     audio_frame_for_mixing->elapsed_time_ms_ = -1;
   } else if (mix_list.size() == 1) {
     audio_frame_for_mixing->timestamp_ = mix_list[0]->timestamp_;
     audio_frame_for_mixing->elapsed_time_ms_ = mix_list[0]->elapsed_time_ms_;
     audio_frame_for_mixing->ntp_time_ms_ = mix_list[0]->ntp_time_ms_;
   }
 }

 void MixFewFramesWithNoLimiter(const std::vector<AudioFrame*>& mix_list,
                                AudioFrame* audio_frame_for_mixing) {
   if (mix_list.empty()) {
     audio_frame_for_mixing->Mute();
     return;
   }
   RTC_DCHECK_LE(mix_list.size(), 1);
   std::copy(mix_list[0]->data(),
             mix_list[0]->data() +
                 mix_list[0]->num_channels_ * mix_list[0]->samples_per_channel_,
             audio_frame_for_mixing->mutable_data());
 }

 void MixToFloatFrame(const std::vector<AudioFrame*>& mix_list,
                      size_t samples_per_channel,
                      size_t number_of_channels,
                      MixingBuffer* mixing_buffer) {
   RTC_DCHECK_LE(samples_per_channel, FrameCombiner::kMaximumChannelSize);
   RTC_DCHECK_LE(number_of_channels, FrameCombiner::kMaximumNumberOfChannels);
   // Clear the mixing buffer.
   for (auto& one_channel_buffer : *mixing_buffer) {
     std::fill(one_channel_buffer.begin(), one_channel_buffer.end(), 0.f);
   }

   // Convert to FloatS16 and mix.
   for (size_t i = 0; i < mix_list.size(); ++i) {
     const AudioFrame* const frame = mix_list[i];
     for (size_t j = 0; j < std::min(number_of_channels,
                                     FrameCombiner::kMaximumNumberOfChannels);
          ++j) {
       for (size_t k = 0; k < std::min(samples_per_channel,
                                       FrameCombiner::kMaximumChannelSize);
            ++k) {
         (*mixing_buffer)[j][k] += frame->data()[number_of_channels * k + j];
       }
     }
   }
 }

 void RunLimiter(AudioFrameView<float> mixing_buffer_view, Limiter* limiter) {
   const size_t sample_rate = mixing_buffer_view.samples_per_channel() * 1000 /
                              AudioMixerImpl::kFrameDurationInMs;
   // TODO(alessiob): Avoid calling SetSampleRate every time.
   limiter->SetSampleRate(sample_rate);
   limiter->Process(mixing_buffer_view);
 }

 // Both interleaves and rounds.
 void InterleaveToAudioFrame(AudioFrameView<const float> mixing_buffer_view,
                             AudioFrame* audio_frame_for_mixing) {
   const size_t number_of_channels = mixing_buffer_view.num_channels();
   const size_t samples_per_channel = mixing_buffer_view.samples_per_channel();
   // Put data in the result frame.
   for (size_t i = 0; i < number_of_channels; ++i) {
     for (size_t j = 0; j < samples_per_channel; ++j) {
       audio_frame_for_mixing->mutable_data()[number_of_channels * j + i] =
           FloatS16ToS16(mixing_buffer_view.channel(i)[j]);
     }
   }
 }
 }  // namespace

 constexpr size_t FrameCombiner::kMaximumNumberOfChannels;
 constexpr size_t FrameCombiner::kMaximumChannelSize;

 FrameCombiner::FrameCombiner(bool use_limiter)
     : data_dumper_(new ApmDataDumper(0)),
       mixing_buffer_(
           absl::make_unique<std::array<std::array<float, kMaximumChannelSize>,
                                        kMaximumNumberOfChannels>>()),
       limiter_(static_cast<size_t>(48000), data_dumper_.get(), "AudioMixer"),
       use_limiter_(use_limiter) {
   static_assert(kMaximumChannelSize * kMaximumNumberOfChannels <=
                     AudioFrame::kMaxDataSizeSamples,
                 "");
 }

 FrameCombiner::~FrameCombiner() = default;

 void FrameCombiner::Combine(const std::vector<AudioFrame*>& mix_list,
                             size_t number_of_channels,
                             int sample_rate,
                             size_t number_of_streams,
                             AudioFrame* audio_frame_for_mixing) {
   RTC_DCHECK(audio_frame_for_mixing);

   LogMixingStats(mix_list, sample_rate, number_of_streams);

   SetAudioFrameFields(mix_list, number_of_channels, sample_rate,
                       number_of_streams, audio_frame_for_mixing);

   const size_t samples_per_channel = static_cast<size_t>(
       (sample_rate * webrtc::AudioMixerImpl::kFrameDurationInMs) / 1000);

   for (const auto* frame : mix_list) {
     RTC_DCHECK_EQ(samples_per_channel, frame->samples_per_channel_);
     RTC_DCHECK_EQ(sample_rate, frame->sample_rate_hz_);
   }

   // The 'num_channels_' field of frames in 'mix_list' could be
   // different from 'number_of_channels'.
   for (auto* frame : mix_list) {
     RemixFrame(number_of_channels, frame);
   }

   if (number_of_streams <= 1) {
     MixFewFramesWithNoLimiter(mix_list, audio_frame_for_mixing);
     return;
   }

   MixToFloatFrame(mix_list, samples_per_channel, number_of_channels,
                   mixing_buffer_.get());

   const size_t output_number_of_channels =
       std::min(number_of_channels, kMaximumNumberOfChannels);
   const size_t output_samples_per_channel =
       std::min(samples_per_channel, kMaximumChannelSize);

   // Put float data in an AudioFrameView.
   std::array<float*, kMaximumNumberOfChannels> channel_pointers{};
   for (size_t i = 0; i < output_number_of_channels; ++i) {
     channel_pointers[i] = &(*mixing_buffer_.get())[i][0];
   }
   AudioFrameView<float> mixing_buffer_view(&channel_pointers[0],
                                            output_number_of_channels,
                                            output_samples_per_channel);

   if (use_limiter_) {
     RunLimiter(mixing_buffer_view, &limiter_);
   }

   InterleaveToAudioFrame(mixing_buffer_view, audio_frame_for_mixing);
 }

 void FrameCombiner::LogMixingStats(const std::vector<AudioFrame*>& mix_list,
                                    int sample_rate,
                                    size_t number_of_streams) const {
   // Log every second.
   uma_logging_counter_++;
   if (uma_logging_counter_ > 1000 / AudioMixerImpl::kFrameDurationInMs) {
     uma_logging_counter_ = 0;
     RTC_HISTOGRAM_COUNTS_100("WebRTC.Audio.AudioMixer.NumIncomingStreams",
                              static_cast<int>(number_of_streams));
     RTC_HISTOGRAM_ENUMERATION(
         "WebRTC.Audio.AudioMixer.NumIncomingActiveStreams",
         static_cast<int>(mix_list.size()),
         AudioMixerImpl::kMaximumAmountOfMixedAudioSources);

     using NativeRate = AudioProcessing::NativeRate;
     static constexpr NativeRate native_rates[] = {
         NativeRate::kSampleRate8kHz, NativeRate::kSampleRate16kHz,
         NativeRate::kSampleRate32kHz, NativeRate::kSampleRate48kHz};
     const auto* rate_position = std::lower_bound(
         std::begin(native_rates), std::end(native_rates), sample_rate);

     RTC_HISTOGRAM_ENUMERATION(
         "WebRTC.Audio.AudioMixer.MixingRate",
         std::distance(std::begin(native_rates), rate_position),
         arraysize(native_rates));
   }
 }

 }  // namespace webrtc
	/*
	* Copyright (c) 2017 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_mixer/frame_combiner.h"

	#include <algorithm>
	#include <array>
	#include <cstdint>
	#include <iterator>
	#include <string>

	#include "absl/memory/memory.h"
	#include "api/array_view.h"
	#include "common_audio/include/audio_util.h"
	#include "modules/audio_mixer/audio_frame_manipulator.h"
	#include "modules/audio_mixer/audio_mixer_impl.h"
	#include "modules/audio_processing/include/audio_frame_view.h"
	#include "modules/audio_processing/include/audio_processing.h"
	#include "modules/audio_processing/logging/apm_data_dumper.h"
	#include "rtc_base/arraysize.h"
	#include "rtc_base/checks.h"
	#include "system_wrappers/include/metrics.h"

	namespace webrtc {
	namespace {

	using MixingBuffer =
	std::array<std::array<float, FrameCombiner::kMaximumChannelSize>,
	FrameCombiner::kMaximumNumberOfChannels>;

	void SetAudioFrameFields(const std::vector<AudioFrame*>& mix_list,
	size_t number_of_channels,
	int sample_rate,
	size_t number_of_streams,
	AudioFrame* audio_frame_for_mixing) {
	const size_t samples_per_channel = static_cast<size_t>(
	(sample_rate * webrtc::AudioMixerImpl::kFrameDurationInMs) / 1000);

	// TODO(minyue): Issue bugs.webrtc.org/3390.
	// Audio frame timestamp. The 'timestamp_' field is set to dummy
	// value '0', because it is only supported in the one channel case and
	// is then updated in the helper functions.
	audio_frame_for_mixing->UpdateFrame(
	0, nullptr, samples_per_channel, sample_rate, AudioFrame::kUndefined,
	AudioFrame::kVadUnknown, number_of_channels);

	if (mix_list.empty()) {
	audio_frame_for_mixing->elapsed_time_ms_ = -1;
	} else if (mix_list.size() == 1) {
	audio_frame_for_mixing->timestamp_ = mix_list[0]->timestamp_;
	audio_frame_for_mixing->elapsed_time_ms_ = mix_list[0]->elapsed_time_ms_;
	audio_frame_for_mixing->ntp_time_ms_ = mix_list[0]->ntp_time_ms_;
	}
	}

	void MixFewFramesWithNoLimiter(const std::vector<AudioFrame*>& mix_list,
	AudioFrame* audio_frame_for_mixing) {
	if (mix_list.empty()) {
	audio_frame_for_mixing->Mute();
	return;
	}
	RTC_DCHECK_LE(mix_list.size(), 1);
	std::copy(mix_list[0]->data(),
	mix_list[0]->data() +
	mix_list[0]->num_channels_ * mix_list[0]->samples_per_channel_,
	audio_frame_for_mixing->mutable_data());
	}

	void MixToFloatFrame(const std::vector<AudioFrame*>& mix_list,
	size_t samples_per_channel,
	size_t number_of_channels,
	MixingBuffer* mixing_buffer) {
	RTC_DCHECK_LE(samples_per_channel, FrameCombiner::kMaximumChannelSize);
	RTC_DCHECK_LE(number_of_channels, FrameCombiner::kMaximumNumberOfChannels);
	// Clear the mixing buffer.
	for (auto& one_channel_buffer : *mixing_buffer) {
	std::fill(one_channel_buffer.begin(), one_channel_buffer.end(), 0.f);
	}

	// Convert to FloatS16 and mix.
	for (size_t i = 0; i < mix_list.size(); ++i) {
	const AudioFrame* const frame = mix_list[i];
	for (size_t j = 0; j < std::min(number_of_channels,
	FrameCombiner::kMaximumNumberOfChannels);
	++j) {
	for (size_t k = 0; k < std::min(samples_per_channel,
	FrameCombiner::kMaximumChannelSize);
	++k) {
	(mixing_buffer)[j][k] += frame->data()[number_of_channels k + j];
	}
	}
	}
	}

	void RunLimiter(AudioFrameView<float> mixing_buffer_view, Limiter* limiter) {
	const size_t sample_rate = mixing_buffer_view.samples_per_channel() * 1000 /
	AudioMixerImpl::kFrameDurationInMs;
	// TODO(alessiob): Avoid calling SetSampleRate every time.
	limiter->SetSampleRate(sample_rate);
	limiter->Process(mixing_buffer_view);
	}

	// Both interleaves and rounds.
	void InterleaveToAudioFrame(AudioFrameView<const float> mixing_buffer_view,
	AudioFrame* audio_frame_for_mixing) {
	const size_t number_of_channels = mixing_buffer_view.num_channels();
	const size_t samples_per_channel = mixing_buffer_view.samples_per_channel();
	// Put data in the result frame.
	for (size_t i = 0; i < number_of_channels; ++i) {
	for (size_t j = 0; j < samples_per_channel; ++j) {
	audio_frame_for_mixing->mutable_data()[number_of_channels * j + i] =
	FloatS16ToS16(mixing_buffer_view.channel(i)[j]);
	}
	}
	}
	} // namespace

	constexpr size_t FrameCombiner::kMaximumNumberOfChannels;
	constexpr size_t FrameCombiner::kMaximumChannelSize;

	FrameCombiner::FrameCombiner(bool use_limiter)
	: data_dumper_(new ApmDataDumper(0)),
	mixing_buffer_(
	absl::make_unique<std::array<std::array<float, kMaximumChannelSize>,
	kMaximumNumberOfChannels>>()),
	limiter_(static_cast<size_t>(48000), data_dumper_.get(), "AudioMixer"),
	use_limiter_(use_limiter) {
	static_assert(kMaximumChannelSize * kMaximumNumberOfChannels <=
	AudioFrame::kMaxDataSizeSamples,
	"");
	}

	FrameCombiner::~FrameCombiner() = default;

	void FrameCombiner::Combine(const std::vector<AudioFrame*>& mix_list,
	size_t number_of_channels,
	int sample_rate,
	size_t number_of_streams,
	AudioFrame* audio_frame_for_mixing) {
	RTC_DCHECK(audio_frame_for_mixing);

	LogMixingStats(mix_list, sample_rate, number_of_streams);

	SetAudioFrameFields(mix_list, number_of_channels, sample_rate,
	number_of_streams, audio_frame_for_mixing);

	const size_t samples_per_channel = static_cast<size_t>(
	(sample_rate * webrtc::AudioMixerImpl::kFrameDurationInMs) / 1000);

	for (const auto* frame : mix_list) {
	RTC_DCHECK_EQ(samples_per_channel, frame->samples_per_channel_);
	RTC_DCHECK_EQ(sample_rate, frame->sample_rate_hz_);
	}

	// The 'num_channels_' field of frames in 'mix_list' could be
	// different from 'number_of_channels'.
	for (auto* frame : mix_list) {
	RemixFrame(number_of_channels, frame);
	}

	if (number_of_streams <= 1) {
	MixFewFramesWithNoLimiter(mix_list, audio_frame_for_mixing);
	return;
	}

	MixToFloatFrame(mix_list, samples_per_channel, number_of_channels,
	mixing_buffer_.get());

	const size_t output_number_of_channels =
	std::min(number_of_channels, kMaximumNumberOfChannels);
	const size_t output_samples_per_channel =
	std::min(samples_per_channel, kMaximumChannelSize);

	// Put float data in an AudioFrameView.
	std::array<float*, kMaximumNumberOfChannels> channel_pointers{};
	for (size_t i = 0; i < output_number_of_channels; ++i) {
	channel_pointers[i] = &(*mixing_buffer_.get())[i][0];
	}
	AudioFrameView<float> mixing_buffer_view(&channel_pointers[0],
	output_number_of_channels,
	output_samples_per_channel);

	if (use_limiter_) {
	RunLimiter(mixing_buffer_view, &limiter_);
	}

	InterleaveToAudioFrame(mixing_buffer_view, audio_frame_for_mixing);
	}

	void FrameCombiner::LogMixingStats(const std::vector<AudioFrame*>& mix_list,
	int sample_rate,
	size_t number_of_streams) const {
	// Log every second.
	uma_logging_counter_++;
	if (uma_logging_counter_ > 1000 / AudioMixerImpl::kFrameDurationInMs) {
	uma_logging_counter_ = 0;
	RTC_HISTOGRAM_COUNTS_100("WebRTC.Audio.AudioMixer.NumIncomingStreams",
	static_cast<int>(number_of_streams));
	RTC_HISTOGRAM_ENUMERATION(
	"WebRTC.Audio.AudioMixer.NumIncomingActiveStreams",
	static_cast<int>(mix_list.size()),
	AudioMixerImpl::kMaximumAmountOfMixedAudioSources);

	using NativeRate = AudioProcessing::NativeRate;
	static constexpr NativeRate native_rates[] = {
	NativeRate::kSampleRate8kHz, NativeRate::kSampleRate16kHz,
	NativeRate::kSampleRate32kHz, NativeRate::kSampleRate48kHz};
	const auto* rate_position = std::lower_bound(
	std::begin(native_rates), std::end(native_rates), sample_rate);

	RTC_HISTOGRAM_ENUMERATION(
	"WebRTC.Audio.AudioMixer.MixingRate",
	std::distance(std::begin(native_rates), rate_position),
	arraysize(native_rates));
	}
	}

	} // namespace webrtc