android获取音量分贝值

AudioRecordDemo.java

package com.example.recording;import android.media.AudioFormat;import android.media.AudioRecord;import android.media.MediaRecorder;import android.util.Log;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); if(volume>80){Log.d(TAG, "恭喜您获得一元优惠券");  } // 大概一秒十次  synchronized (mLock) {  try {  mLock.wait(100);  } catch (InterruptedException e) {  e.printStackTrace();  }  }  }  mAudioRecord.stop();  mAudioRecord.release();  mAudioRecord = null;  }  }).start();  }  }

MediaRecorderDemo.java

package com.example.recording;import java.io.File;import java.io.IOException;import android.media.MediaRecorder;import android.os.Handler;import android.util.Log;public class MediaRecorderDemo {private final String TAG = "MediaRecord";  private MediaRecorder mMediaRecorder;  public static final int MAX_LENGTH = 1000 * 60 * 10;// 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 = 1;  private int SPACE = 100;// 间隔取样时间  private void updateMicStatus() {  if (mMediaRecorder != null) {  double ratio = (double)mMediaRecorder.getMaxAmplitude() /BASE;  double db = 0;// 分贝  if (ratio > 1)  db = 20 * Math.log10(ratio);  Log.d(TAG,"分贝值："+db);  mHandler.postDelayed(mUpdateMicStatusTimer, SPACE);  }  }  }

MainActivity.java

package com.example.recording;import android.os.Bundle;import android.app.Activity;import android.view.Menu;public class MainActivity extends Activity {@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);new AudioRecordDemo().getNoiseLevel();}}

activity_main.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:tools="http://schemas.android.com/tools"    android:layout_width="match_parent"    android:layout_height="match_parent"    android:paddingBottom="@dimen/activity_vertical_margin"    android:paddingLeft="@dimen/activity_horizontal_margin"    android:paddingRight="@dimen/activity_horizontal_margin"    android:paddingTop="@dimen/activity_vertical_margin"    tools:context=".MainActivity" >    <TextView        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:text="@string/hello_world" /></RelativeLayout>

最后别忘了，在AndroidManifest.xml中配置

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

源码：http://download.csdn.net/detail/zhupengqq/9584312