Android音频开发之音频采集的实现示例

//设置采集来源为麦克风
private static final int AUDIO_RESOURCE = MediaRecorder.AudioSource.MIC;
//设置采样率为44100，目前为常用的采样率，官方文档表示这个值可以兼容所有的设置
private final static int AUDIO_SAMPLE_RATE = 44100;
//设置声道声道数量为双声道
private final static int CHANNEL_CONFIG = AudioFormat.CHANNEL_IN_STEREO;
//设置采样精度，将采样的数据以PCM进行编码，每次采集的数据位宽为16bit。
private final static int AUDIO_FORMAT = AudioFormat.ENCODING_PCM_16BIT;

public AudioRecord(int audioSource, int sampleRateInHz, int channelConfig, int audioFormat, int bufferSizeInBytes)

public void startRecording ()

public int read (ByteBuffer audioBuffer, int sizeInBytes)
public int read (byte[] audioData, int offsetInBytes, int sizeInBytes)
public int read (short[] audioData, int offsetInShorts, int sizeInShorts)

public void stop ()

public int getState ()

public int getRecordingState()

<uses-permission android:name="android.permission.RECORD_AUDIO" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

if (AudioRecord.ERROR_BAD_VALUE == bufferSizeInBytes || AudioRecord.ERROR == bufferSizeInBytes) {
  throw new RuntimeException("Unable to getMinBufferSize");
}

//bufferSizeInBytes is available...

//判断AudioRecord的状态是否初始化完毕
//在AudioRecord对象构造完毕之后，就处于AudioRecord.STATE_INITIALIZED状态了。
int state = audioRecord.getState();
if (state == AudioRecord.STATE_UNINITIALIZED) {
  throw new RuntimeException("AudioRecord STATE_UNINITIALIZED");
}

audioRecord.startRecording();
//开启线程读取数据
new Thread(recordTask).start();

//创建一个流，存放从AudioRecord读取的数据
File saveFile = new File(Environment.getExternalStorageDirectory(), "audio-record.pcm");
DataOutputStream dataOutputStream = new DataOutputStream(
        new BufferedOutputStream(new FileOutputStream(saveFile)));

private Runnable recordTask = new Runnable() {
  @Override
  public void run() {
    //设置线程的优先级
    android.os.Process.setThreadPriority(android.os.Process.THREAD_PRIOR
    Log.i(TAG, "设置采集音频线程优先级");
    final byte[] data = new byte[bufferSizeInBytes];
    //标记为开始采集状态
    isRecording = true;
    Log.i(TAG, "设置当前当前状态为采集状态");
    //getRecordingState获取当前AudioReroding是否正在采集数据的状态
    while (isRecording && audioRecord.getRecordingState() == AudioRecord
      //读取采集数据到缓冲区中，read就是读取到的数据量
      final int read = audioRecord.read(data, 0, bufferSizeInBytes);
      if (AudioRecord.ERROR_INVALID_OPERATION != read && AudioRecord.E
        //将数据写入到文件中
        dataOutputStream.write(buffer,0,read);
      }
    }
  }
};

/**
 * 停止录音
 */
public void stopRecord() throws IOException {
  Log.i(TAG, "停止录音，回收AudioRecord对象，释放内存");
  isRecording = false;
  if (audioRecord != null) {
    if (audioRecord.getRecordingState() == AudioRecord.RECORDSTATE_RECORDING) {
      audioRecord.stop();
      Log.i(TAG, "audioRecord.stop()");
    }
    if (audioRecord.getState() == AudioRecord.STATE_INITIALIZED) {
      audioRecord.release();
      Log.i(TAG, "audioRecord.release()");
    }
  }
}