AudioRecord类获取录音音量分贝数

转自:http://www.jb51.net/article/64806.htm

 

public class AudioRecordDemo {

 

  private static final String TAG = "AudioRecord";

  static final int SAMPLE_RATE_IN_HZ = 8000;

  static final int BUFFER_SIZE = AudioRecord.getMinBufferSize(SAMPLE_RATE_IN_HZ,

          AudioFormat.CHANNEL_IN_DEFAULT, AudioFormat.ENCODING_PCM_16BIT);

  AudioRecord mAudioRecord;

  boolean isGetVoiceRun;

  Object mLock;

 

  public AudioRecordDemo() {

    mLock = new Object();

  }

 

  public void getNoiseLevel() {

    if (isGetVoiceRun) {

      Log.e(TAG, "还在录着呢");

      return;

    }

    mAudioRecord = new AudioRecord(MediaRecorder.AudioSource.MIC,

        SAMPLE_RATE_IN_HZ, AudioFormat.CHANNEL_IN_DEFAULT,

        AudioFormat.ENCODING_PCM_16BIT, BUFFER_SIZE);

    if (mAudioRecord == null) {

      Log.e("sound", "mAudioRecord初始化失败");

    }

    isGetVoiceRun = true;

 

    new Thread(new Runnable() {

      @Override

      public void run() {

        mAudioRecord.startRecording();

        short[] buffer = new short[BUFFER_SIZE];

        while (isGetVoiceRun) {

          //r是实际读取的数据长度，一般而言r会小于buffersize

          int r = mAudioRecord.read(buffer, 0, BUFFER_SIZE);

          long v = 0;

          // 将 buffer 内容取出，进行平方和运算

          for (int i = 0; i < buffer.length; i++) {

            v += buffer[i] * buffer[i];

          }

          // 平方和除以数据总长度，得到音量大小。

          double mean = v / (double) r;

          double volume = 10 * Math.log10(mean);

          Log.d(TAG, "分贝值:" + volume);

          // 大概一秒十次

          synchronized (mLock) {

            try {

              mLock.wait(100);

            } catch (InterruptedException e) {

              e.printStackTrace();

            }

          }

        }

        mAudioRecord.stop();

        mAudioRecord.release();

        mAudioRecord = null;

      }

    }).start();

  }

}