| // Copyright 2021 The Chromium Authors |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #ifndef SERVICES_AUDIO_MIXING_GRAPH_IMPL_H_ |
| #define SERVICES_AUDIO_MIXING_GRAPH_IMPL_H_ |
| |
| #include "base/gtest_prod_util.h" |
| #include "services/audio/mixing_graph.h" |
| |
| #include <map> |
| |
| #include "base/synchronization/lock.h" |
| |
| namespace media { |
| class LoopbackAudioConverter; |
| } |
| |
| namespace audio { |
| |
| class MixingGraphImpl : public MixingGraph { |
| public: |
| using CreateConverterCallback = |
| base::RepeatingCallback<std::unique_ptr<media::LoopbackAudioConverter>( |
| const media::AudioParameters& input_params, |
| const media::AudioParameters& output_params)>; |
| MixingGraphImpl(const media::AudioParameters& output_params, |
| OnMoreDataCallback on_more_data_cb, |
| OnErrorCallback on_error_cb); |
| MixingGraphImpl(const media::AudioParameters& output_params, |
| OnMoreDataCallback on_more_data_cb, |
| OnErrorCallback on_error_cb, |
| CreateConverterCallback create_converter_cb); |
| ~MixingGraphImpl() override; |
| |
| std::unique_ptr<Input> CreateInput( |
| const media::AudioParameters& params) final; |
| void AddInput(Input* node) final; |
| void RemoveInput(Input* node) final; |
| |
| // media::AudioOutputStream::AudioSourceCallback |
| int OnMoreData(base::TimeDelta delay, |
| base::TimeTicks delay_timestamp, |
| int prior_frames_skipped, |
| media::AudioBus* dest) final; |
| |
| void OnError(ErrorType type) final; |
| |
| protected: |
| class OvertimeLogger; |
| |
| media::LoopbackAudioConverter* FindOrAddConverter( |
| const media::AudioParameters& input_params, |
| const media::AudioParameters& output_params, |
| media::LoopbackAudioConverter* parent_converter); |
| |
| class AudioConverterKey { |
| public: |
| explicit AudioConverterKey(const media::AudioParameters& params) |
| : sample_rate_(params.sample_rate()), |
| channel_layout_(params.channel_layout()), |
| channels_(params.channels()) {} |
| |
| inline bool operator==(const AudioConverterKey& other) const { |
| return sample_rate_ == other.sample_rate_ && |
| channel_layout_ == other.channel_layout_ && |
| channels_ == other.channels_; |
| } |
| |
| inline bool operator<(const AudioConverterKey& other) const { |
| if (sample_rate_ != other.sample_rate_) |
| return sample_rate_ < other.sample_rate_; |
| if (channel_layout_ != other.channel_layout_) |
| return channel_layout_ < other.channel_layout_; |
| return channels_ < other.channels_; |
| } |
| |
| inline bool SameChannelSetup(const media::AudioParameters& params) const { |
| return channel_layout_ == params.channel_layout() && |
| channels_ == params.channels(); |
| } |
| |
| inline void UpdateChannelSetup(const media::AudioParameters& params) { |
| channel_layout_ = params.channel_layout(); |
| channels_ = params.channels(); |
| } |
| |
| inline int sample_rate() const { return sample_rate_; } |
| |
| inline void set_sample_rate(int sample_rate) { sample_rate_ = sample_rate; } |
| |
| private: |
| int sample_rate_; |
| media::ChannelLayout channel_layout_; |
| int channels_; |
| }; |
| FRIEND_TEST_ALL_PREFIXES(MixingGraphImpl, AudioConverterKeySorting); |
| |
| void Remove(const AudioConverterKey& key, |
| media::AudioConverter::InputCallback* input); |
| |
| using AudioConverters = |
| std::map<AudioConverterKey, |
| std::unique_ptr<media::LoopbackAudioConverter>>; |
| |
| SEQUENCE_CHECKER(owning_sequence_); |
| |
| // The audio format of the mixed audio leaving the mixing graph. |
| const media::AudioParameters output_params_; |
| // Called from OnMoreData() with mixed audio as input. |
| const OnMoreDataCallback on_more_data_cb_; |
| // Notifies the client about audio rendering errors. |
| const OnErrorCallback on_error_cb_; |
| // Called when a new converter needs to be created. |
| const CreateConverterCallback create_converter_cb_; |
| |
| // UMA logging. |
| const std::unique_ptr<OvertimeLogger> overtime_logger_; |
| |
| base::Lock lock_; |
| |
| // The |main_converter_|, the |converters_| and the inputs are connected |
| // to form a graph (tree structure) that determines how the input audio is |
| // channel mixed, resampled, and added to the final output. Channel mixing |
| // and resampling are handled by converters. The tree is constructed to |
| // minimize the use of resampling, which is the most complex operation. |
| // 1. For inputs with a channel layout different from the output channel |
| // layout: All inputs of the same sample rate and channel layout are combined |
| // and channel mixed to produce new inputs with the output channel layout. |
| // 2. For inputs with a sample rate different from the output sample rate: All |
| // inputs of the same sample rate (and after channel mixing the same channel |
| // layout) are combined and resampled to produce new inputs of the |
| // output sample rate (and channel layout). |
| // 3. All inputs of the output sample rate and channel layout are combined by |
| // the main converter to produce a single output. |
| AudioConverters converters_; |
| media::AudioConverter main_converter_; |
| }; |
| |
| } // namespace audio |
| #endif // SERVICES_AUDIO_MIXING_GRAPH_IMPL_H_ |