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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_SINK_H_
#define MEDIA_BASE_AUDIO_RENDERER_SINK_H_
#include <vector>
#include "base/basictypes.h"
#include "base/memory/ref_counted.h"
#include "media/audio/audio_parameters.h"
#include "media/base/media_export.h"
namespace media {
// AudioRendererSink is an interface representing the end-point for
// rendered audio. An implementation is expected to
// periodically call Render() on a callback object.
class AudioRendererSink
: public base::RefCountedThreadSafe<media::AudioRendererSink> {
public:
class RenderCallback {
public:
// Fills entire buffer of length |number_of_frames| but returns actual
// number of frames it got from its source (|number_of_frames| in case of
// continuous stream). That actual number of frames is passed to host
// together with PCM audio data and host is free to use or ignore it.
// TODO(crogers): use base:Callback instead.
virtual int Render(const std::vector<float*>& audio_data,
int number_of_frames,
int audio_delay_milliseconds) = 0;
// Signals an error has occurred.
virtual void OnRenderError() = 0;
protected:
virtual ~RenderCallback() {}
};
// Sets important information about the audio stream format.
// It must be called before any of the other methods.
virtual void Initialize(const AudioParameters& params,
RenderCallback* callback) = 0;
// Starts audio playback.
virtual void Start() = 0;
// Stops audio playback.
virtual void Stop() = 0;
// Pauses playback.
virtual void Pause(bool flush) = 0;
// Resumes playback after calling Pause().
virtual void Play() = 0;
// Sets the playback volume, with range [0.0, 1.0] inclusive.
// Returns |true| on success.
virtual bool SetVolume(double volume) = 0;
protected:
friend class base::RefCountedThreadSafe<AudioRendererSink>;
virtual ~AudioRendererSink() {}
};
} // namespace media
#endif // MEDIA_BASE_AUDIO_RENDERER_SINK_H_