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// Copyright (c) 2006-2008 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_AUDIO_SIMPLE_SOURCES_H_
#define MEDIA_AUDIO_SIMPLE_SOURCES_H_
#include <list>
#include "base/lock.h"
#include "media/audio/audio_output.h"
// An audio source that produces a pure sinusoidal tone.
class SineWaveAudioSource : public AudioOutputStream::AudioSourceCallback {
public:
enum Format {
FORMAT_8BIT_LINEAR_PCM,
FORMAT_16BIT_LINEAR_PCM,
};
// |channels| is the number of audio channels, |freq| is the frequency in
// hertz and it has to be less than half of the sampling frequency
// |sample_freq| or else you will get aliasing.
SineWaveAudioSource(Format format, int channels,
double freq, double sample_freq);
virtual ~SineWaveAudioSource() {}
// Implementation of AudioSourceCallback.
virtual size_t OnMoreData(AudioOutputStream* stream,
void* dest, size_t max_size, int pending_bytes);
virtual void OnClose(AudioOutputStream* stream);
virtual void OnError(AudioOutputStream* stream, int code);
protected:
Format format_;
int channels_;
double freq_;
double sample_freq_;
};
// Defines an interface for pushing audio output. In contrast, the interfaces
// defined by AudioSourceCallback are pull model only.
class PushAudioOutput {
public:
virtual ~PushAudioOutput(){}
// Write audio data to the audio device. It will be played eventually.
// Returns false on failure.
virtual bool Write(const void* data, size_t len) = 0;
// Returns the number of bytes that have been buffered but not yet given
// to the audio device.
virtual size_t UnProcessedBytes() = 0;
};
// A fairly basic class to connect a push model provider PushAudioOutput to
// a pull model provider AudioSourceCallback. Fundamentally it manages a series
// of audio buffers and is unaware of the actual audio format.
class PushSource : public AudioOutputStream::AudioSourceCallback,
public PushAudioOutput {
public:
// Construct the audio source. Pass the same |packet_size| specified in the
// AudioOutputStream::Open() here.
// TODO(hclam): |packet_size| is not used anymore, remove it.
explicit PushSource(size_t packet_size);
virtual ~PushSource();
// Write one buffer. The ideal size is |packet_size| but smaller sizes are
// accepted.
virtual bool Write(const void* data, size_t len);
// Return the total number of bytes not given to the audio device yet.
virtual size_t UnProcessedBytes();
// Implementation of AudioSourceCallback.
virtual size_t OnMoreData(AudioOutputStream* stream,
void* dest, size_t max_size, int pending_bytes);
virtual void OnClose(AudioOutputStream* stream);
virtual void OnError(AudioOutputStream* stream, int code);
private:
// Defines the unit of playback. We own the memory pointed by |buffer|.
struct Packet {
char* buffer;
size_t size;
};
// Free acquired resources.
void CleanUp();
const size_t packet_size_;
typedef std::list<Packet> PacketList;
PacketList packets_;
size_t buffered_bytes_;
size_t front_buffer_consumed_;
// Serialize access to packets_ and buffered_bytes_ using this lock.
Lock lock_;
};
#endif // MEDIA_AUDIO_SIMPLE_SOURCES_H_
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