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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 <string>
#include "base/macros.h"
#include "base/memory/scoped_ptr.h"
#include "base/synchronization/lock.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
: NON_EXPORTED_BASE(public AudioRendererSink::RenderCallback) {
public:
AudioRendererMixer(const AudioParameters& output_params,
const scoped_refptr<AudioRendererSink>& sink);
~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 set_pause_delay_for_testing(base::TimeDelta delay) {
pause_delay_ = delay;
}
// TODO(guidou): remove this method. The output device of a mixer should
// never be switched, as it may result in a discrepancy between the output
// parameters of the new device and the output parameters with which the
// mixer was initialized. See crbug.com/506507
OutputDevice* GetOutputDevice();
private:
// Maps input sample rate to the dedicated converter.
typedef std::map<int, scoped_ptr<LoopbackAudioConverter>> AudioConvertersMap;
// AudioRendererSink::RenderCallback implementation.
int Render(AudioBus* audio_bus,
uint32_t frames_delayed,
uint32_t frames_skipped) override;
void OnRenderError() override;
bool is_master_sample_rate(int sample_rate) {
return sample_rate == output_params_.sample_rate();
}
// Output sink for this mixer.
scoped_refptr<AudioRendererSink> audio_sink_;
// Output parameters for this mixer.
AudioParameters output_params_;
// ---------------[ 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_;
// 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_;
// Master converter which mixes all the outputs from |converters_| as well as
// mixer inputs that are in the output sample rate.
AudioConverter master_converter_;
// 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_;
base::TimeTicks last_play_time_;
bool playing_;
DISALLOW_COPY_AND_ASSIGN(AudioRendererMixer);
};
} // namespace media
#endif // MEDIA_BASE_AUDIO_RENDERER_MIXER_H_
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