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 {

	@Override
	protected 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" />