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// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef MEDIA_BASE_AUDIO_RENDERER_MIXER_H_
#define MEDIA_BASE_AUDIO_RENDERER_MIXER_H_
#include <stdint.h>
#include <map>
#include <memory>
#include "base/containers/flat_map.h"
#include "base/containers/flat_set.h"
#include "base/synchronization/lock.h"
#include "base/thread_annotations.h"
#include "base/time/time.h"
#include "media/base/audio_converter.h"
#include "media/base/audio_renderer_sink.h"
#include "media/base/loopback_audio_converter.h"
namespace media {
class AudioRendererMixerInput;
// Mixes a set of AudioConverter::InputCallbacks into a single output stream
// which is funneled into a single shared AudioRendererSink; saving a bundle
// on renderer side resources.
class MEDIA_EXPORT AudioRendererMixer
: public AudioRendererSink::RenderCallback {
public:
AudioRendererMixer(const AudioParameters& output_params,
scoped_refptr<AudioRendererSink> sink);
AudioRendererMixer(const AudioRendererMixer&) = delete;
AudioRendererMixer& operator=(const AudioRendererMixer&) = delete;
~AudioRendererMixer() override;
// Add or remove a mixer input from mixing; called by AudioRendererMixerInput.
void AddMixerInput(const AudioParameters& input_params,
AudioConverter::InputCallback* input);
void RemoveMixerInput(const AudioParameters& input_params,
AudioConverter::InputCallback* input);
// Since errors may occur even when no inputs are playing, an error callback
// must be registered separately from adding a mixer input.
void AddErrorCallback(AudioRendererMixerInput* input);
void RemoveErrorCallback(AudioRendererMixerInput* input);
// Returns true if called on rendering thread, otherwise false.
bool CurrentThreadIsRenderingThread();
void SetPauseDelayForTesting(base::TimeDelta delay);
const AudioParameters& get_output_params_for_testing() const {
return output_params_;
}
private:
// AudioRendererSink::RenderCallback implementation.
int Render(base::TimeDelta delay,
base::TimeTicks delay_timestamp,
int prior_frames_skipped,
AudioBus* audio_bus) override;
void OnRenderError() override;
bool can_passthrough(int sample_rate) const {
return sample_rate == output_params_.sample_rate();
}
// Output parameters for this mixer.
const AudioParameters output_params_;
// Output sink for this mixer.
const scoped_refptr<AudioRendererSink> audio_sink_;
// ---------------[ All variables below protected by |lock_| ]---------------
base::Lock lock_;
// List of error callbacks used by this mixer.
base::flat_set<AudioRendererMixerInput*> error_callbacks_ GUARDED_BY(lock_);
// Maps input sample rate to the dedicated converter.
using AudioConvertersMap =
base::flat_map<int, std::unique_ptr<LoopbackAudioConverter>>;
// Each of these converters mixes inputs with a given sample rate and
// resamples them to the output sample rate. Inputs not requiring resampling
// go directly to |aggregate_converter_|.
AudioConvertersMap converters_ GUARDED_BY(lock_);
// Aggregate converter which mixes all the outputs from |converters_| as well
// as mixer inputs that are in the output sample rate.
AudioConverter aggregate_converter_ GUARDED_BY(lock_);
// Handles physical stream pause when no inputs are playing. For latency
// reasons we don't want to immediately pause the physical stream.
base::TimeDelta pause_delay_ GUARDED_BY(lock_);
base::TimeTicks last_play_time_ GUARDED_BY(lock_);
bool playing_ GUARDED_BY(lock_);
};
} // namespace media
#endif // MEDIA_BASE_AUDIO_RENDERER_MIXER_H_
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