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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 <string>
#include "base/macros.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 {
// 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:
typedef base::Callback<void(int)> UmaLogCallback;
AudioRendererMixer(const AudioParameters& output_params,
scoped_refptr<AudioRendererSink> sink,
const UmaLogCallback& log_callback);
~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. The same callback
// must be given to both the functions.
void AddErrorCallback(const base::Closure& error_cb);
void RemoveErrorCallback(const base::Closure& error_cb);
void SetPauseDelayForTesting(base::TimeDelta delay);
OutputDeviceInfo GetOutputDeviceInfo();
// Returns true if called on rendering thread, otherwise false.
bool CurrentThreadIsRenderingThread();
const AudioParameters& GetOutputParamsForTesting() { return output_params_; };
private:
class UMAMaxValueTracker;
// Maps input sample rate to the dedicated converter.
using AudioConvertersMap =
std::map<int, std::unique_ptr<LoopbackAudioConverter>>;
// AudioRendererSink::RenderCallback implementation.
int Render(base::TimeDelta delay,
base::TimeTicks delay_timestamp,
int prior_frames_skipped,
AudioBus* audio_bus) override;
void OnRenderError() override;
bool is_master_sample_rate(int sample_rate) {
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.
typedef std::list<base::Closure> ErrorCallbackList;
ErrorCallbackList error_callbacks_ GUARDED_BY(lock_);
// Each of these converters mixes inputs with a given sample rate and
// resamples them to the output sample rate. Inputs not reqiuring resampling
// go directly to |master_converter_|.
AudioConvertersMap converters_ GUARDED_BY(lock_);
// Master converter which mixes all the outputs from |converters_| as well as
// mixer inputs that are in the output sample rate.
AudioConverter master_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_);
// Tracks the maximum number of simultaneous mixer inputs and logs it into
// UMA histogram upon the destruction.
std::unique_ptr<UMAMaxValueTracker> input_count_tracker_ GUARDED_BY(lock_);
DISALLOW_COPY_AND_ASSIGN(AudioRendererMixer);
};
} // namespace media
#endif // MEDIA_BASE_AUDIO_RENDERER_MIXER_H_