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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 "base/callback.h"
#include "base/threading/thread_checker.h"
#include "media/audio/audio_io.h"
#include "media/audio/audio_parameters.h"
#include "media/base/audio_converter.h"
namespace media {
class VirtualAudioInputStream;
// VirtualAudioOutputStream attaches to a VirtualAudioInputStream when Start()
// is called and is used as an audio source. VirtualAudioOutputStream also
// implements an interface so it can be used as an input to AudioConverter so
// that we can get audio frames that match the AudioParameters that
// VirtualAudioInputStream expects.
class MEDIA_EXPORT VirtualAudioOutputStream
: public AudioOutputStream,
public AudioConverter::InputCallback {
// Callback invoked just after VirtualAudioOutputStream is closed.
typedef base::Callback<void(VirtualAudioOutputStream* vaos)>
// Construct an audio loopback pathway to the given |target| (not owned).
// |target| must outlive this instance.
VirtualAudioOutputStream(const AudioParameters& params,
VirtualAudioInputStream* target,
const AfterCloseCallback& after_close_cb);
virtual ~VirtualAudioOutputStream();
// AudioOutputStream:
virtual bool Open() OVERRIDE;
virtual void Start(AudioSourceCallback* callback) OVERRIDE;
virtual void Stop() OVERRIDE;
virtual void SetVolume(double volume) OVERRIDE;
virtual void GetVolume(double* volume) OVERRIDE;
virtual void Close() OVERRIDE;
// AudioConverter::InputCallback:
virtual double ProvideInput(AudioBus* audio_bus,
base::TimeDelta buffer_delay) OVERRIDE;
const AudioParameters params_;
// Pointer to the VirtualAudioInputStream to attach to when Start() is called.
// This pointer should always be valid because VirtualAudioInputStream should
// outlive this class.
VirtualAudioInputStream* const target_input_stream_;
AfterCloseCallback after_close_cb_;
AudioSourceCallback* callback_;
double volume_;
base::ThreadChecker thread_checker_;
} // namespace media