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// Copyright (c) 2010 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_AUDIO_INPUT_CONTROLLER_H_
#define MEDIA_AUDIO_AUDIO_INPUT_CONTROLLER_H_
#include "base/lock.h"
#include "base/ref_counted.h"
#include "base/scoped_ptr.h"
#include "base/thread.h"
#include "media/audio/audio_io.h"
// An AudioInputController controls an AudioInputStream and records data
// from this input stream. It has an important function that it executes
// audio operations like record, pause, stop, etc. on a separate thread.
//
// All the public methods of AudioInputController are non-blocking except
// close, the actual operations are performed on the audio input controller
// thread.
//
// Here is a state diagram for the AudioInputController:
//
// .--> [ Closed / Error ] <--.
// | |
// | |
// [ Created ] ----------> [ Recording ]
// ^
// |
// *[ Empty ]
//
// * Initial state
//
namespace media {
class AudioInputController :
public base::RefCountedThreadSafe<AudioInputController>,
public AudioInputStream::AudioInputCallback {
public:
// An event handler that receives events from the AudioInputController. The
// following methods are called on the audio input controller thread.
class EventHandler {
public:
virtual ~EventHandler() {}
virtual void OnCreated(AudioInputController* controller) = 0;
virtual void OnRecording(AudioInputController* controller) = 0;
virtual void OnError(AudioInputController* controller, int error_code) = 0;
virtual void OnData(AudioInputController* controller, const uint8* data,
uint32 size) = 0;
};
virtual ~AudioInputController();
// Factory method for creating an AudioInputController.
// If successful, an audio input controller thread is created. The audio
// device will be created on the new thread and when that is done event
// handler will receive a OnCreated() call.
static scoped_refptr<AudioInputController> Create(
EventHandler* event_handler,
AudioManager::Format format, // Format of the stream.
int channels, // Number of channels.
int sample_rate, // Sampling frequency/rate.
int bits_per_sample, // Number of bits per sample.
int samples_per_packet); // Size of the hardware buffer.
// Starts recording in this audio input stream.
void Record();
// Closes the audio input stream and shutdown the audio input controller
// thread. This method returns only after all operations are completed. This
// input controller cannot be used after this method is called.
//
// It is safe to call this method more than once. Calls after the first one
// will have no effect.
void Close();
///////////////////////////////////////////////////////////////////////////
// AudioInputCallback methods.
virtual void OnData(AudioInputStream* stream, const uint8* src, uint32 size);
virtual void OnClose(AudioInputStream* stream);
virtual void OnError(AudioInputStream* stream, int code);
private:
// Internal state of the source.
enum State {
kEmpty,
kCreated,
kRecording,
kClosed,
kError
};
AudioInputController(EventHandler* handler);
// The following methods are executed on the audio controller thread.
void DoCreate(AudioManager::Format format, int channels,
int sample_rate, int bits_per_sample,
uint32 samples_per_packet);
void DoRecord();
void DoClose();
void DoReportError(int code);
EventHandler* handler_;
AudioInputStream* stream_;
// |state_| is written on the audio input controller thread and is read on
// the hardware audio thread. These operations need to be locked. But lock
// is not required for reading on the audio input controller thread.
State state_;
Lock lock_;
// The audio input controller thread that this object runs on.
base::Thread thread_;
DISALLOW_COPY_AND_ASSIGN(AudioInputController);
};
} // namespace media
#endif // MEDIA_AUDIO_AUDIO_INPUT_CONTROLLER_H_
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