Android 录音获取分贝值的办法

public class MediaRecorderDemo {
private final String TAG = "MediaRecord";
private MediaRecorder mMediaRecorder;
public static final int MAX_LENGTH = * * ;// 最大录音时长1000*60*10;
private String filePath; public MediaRecorderDemo(){
this.filePath = "/dev/null";
} public MediaRecorderDemo(File file) {
this.filePath = file.getAbsolutePath();
} private long startTime;
private long endTime; /**
* 开始录音 使用amr格式
*
* 录音文件
* @return
*/
public void startRecord() {
// 开始录音
/* ①Initial：实例化MediaRecorder对象 */
if (mMediaRecorder == null)
mMediaRecorder = new MediaRecorder();
try {
/* ②setAudioSource/setVedioSource */
mMediaRecorder.setAudioSource(MediaRecorder.AudioSource.MIC);// 设置麦克风
/* ②设置音频文件的编码：AAC/AMR_NB/AMR_MB/Default 声音的（波形）的采样 */
mMediaRecorder.setOutputFormat(MediaRecorder.OutputFormat.DEFAULT);
/*
* ②设置输出文件的格式：THREE_GPP/MPEG-4/RAW_AMR/Default THREE_GPP(3gp格式
* ，H263视频/ARM音频编码)、MPEG-4、RAW_AMR(只支持音频且音频编码要求为AMR_NB)
*/
mMediaRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB); /* ③准备 */
mMediaRecorder.setOutputFile(filePath);
mMediaRecorder.setMaxDuration(MAX_LENGTH);
mMediaRecorder.prepare();
/* ④开始 */
mMediaRecorder.start();
// AudioRecord audioRecord.
/* 获取开始时间* */
startTime = System.currentTimeMillis();
updateMicStatus();
Log.i("ACTION_START", "startTime" + startTime);
} catch (IllegalStateException e) {
Log.i(TAG,
"call startAmr(File mRecAudioFile) failed!"
+ e.getMessage());
} catch (IOException e) {
Log.i(TAG,
"call startAmr(File mRecAudioFile) failed!"
+ e.getMessage());
}
} /**
* 停止录音
*
*/
public long stopRecord() {
if (mMediaRecorder == null)
return 0L;
endTime = System.currentTimeMillis();
Log.i("ACTION_END", "endTime" + endTime);
mMediaRecorder.stop();
mMediaRecorder.reset();
mMediaRecorder.release();
mMediaRecorder = null;
Log.i("ACTION_LENGTH", "Time" + (endTime - startTime));
return endTime - startTime;
} private final Handler mHandler = new Handler();
private Runnable mUpdateMicStatusTimer = new Runnable() {
public void run() {
updateMicStatus();
}
}; /**
* 更新话筒状态
*
*/
private int BASE = ;
private int SPACE = ;// 间隔取样时间 private void updateMicStatus() {
if (mMediaRecorder != null) {
double ratio = (double)mMediaRecorder.getMaxAmplitude() /BASE;
double db = ;// 分贝
if (ratio > )
db = * Math.log10(ratio);
Log.d(TAG,"分贝值："+db);
mHandler.postDelayed(mUpdateMicStatusTimer, SPACE);
}
}
}