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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.
#include <map>
#include "base/synchronization/lock.h"
#include "base/time/time.h"
#include "media/base/audio_converter.h"
#include "media/base/audio_renderer_sink.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) {
AudioRendererMixer(const AudioParameters& input_params,
const AudioParameters& output_params,
const scoped_refptr<AudioRendererSink>& sink);
~AudioRendererMixer() override;
// Add or remove a mixer input from mixing; called by AudioRendererMixerInput.
void AddMixerInput(AudioConverter::InputCallback* input);
void RemoveMixerInput(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;
// AudioRendererSink::RenderCallback implementation.
int Render(AudioBus* audio_bus, int audio_delay_milliseconds) override;
void OnRenderError() override;
// Output sink for this mixer.
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_;
// Handles mixing and resampling between input and output parameters.
AudioConverter audio_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_;
} // namespace media