Java 写wav文件

关于wav的文件结构网上能抓到一大把，这里只是简单的提一下。
wav文件分4个块，RIFF chunk ，Format chunk ，Data chunk是必须的。Fact chunk 可选。

其中RIFFSIZE DataSize 字段需要根据文件字节数计算： RIFFSize=DataSize+36-8; 因为三个chunk大小是36bytes，除去ID字节。

其他参数按照自己需求设置，formattag 如果是采用pcm则为1。

有一点要注意的是写入文件时候要考虑little—Endian和big_endian的区别。wav文件默认的little—endian方式。所以写入数据时要将顺序调整后在写入。
一下是我写的一个例子的代码：

虽然javasound可以直接保存为wav，但是我的实际需求是从需要更底层的控制，所以就自己写了一个demo。从microphone采集音频，并保存为文件。

import java.io.BufferedOutputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStream;

import javax.sound.sampled.AudioFormat;
import javax.sound.sampled.AudioInputStream;
import javax.sound.sampled.AudioSystem;
import javax.sound.sampled.DataLine;
import javax.sound.sampled.LineUnavailableException;
import javax.sound.sampled.TargetDataLine;

public class SpeechStore {

	private static byte[]  RIFF="RIFF".getBytes();
	private static byte[] RIFF_SIZE=new byte[4];
	private static byte[] RIFF_TYPE="WAVE".getBytes();


	private static byte[] FORMAT="fmt ".getBytes();
	private static byte[] FORMAT_SIZE=new byte[4];
	 private static byte[] FORMATTAG=new byte[2];
	 private static byte[] CHANNELS=new byte[2];
	private static byte[] SamplesPerSec =new byte[4];
	private static byte[] AvgBytesPerSec=new byte[4];
	private static byte[] BlockAlign =new byte[2];
	private static byte[] BitsPerSample =new byte[2];

	private static byte[] DataChunkID="data".getBytes();
	private static byte[] DataSize=new byte[4];
	public static boolean isrecording=false;



 public void writeToWave(){

 }

 public static void init(){
//这里主要就是设置参数，要注意revers函数在这里的作用

	 FORMAT_SIZE=new byte[]{(byte)16,(byte)0,(byte)0,(byte)0};
	 byte[] tmp=revers(intToBytes(1));
	 FORMATTAG=new byte[]{tmp[0],tmp[1]};
	 CHANNELS=new byte[]{tmp[0],tmp[1]};
	 SamplesPerSec=revers(intToBytes(16000));
	 AvgBytesPerSec=revers(intToBytes(32000));
	  tmp=revers(intToBytes(2));
	 BlockAlign=new byte[]{tmp[0],tmp[1]};
	 tmp=revers(intToBytes(16));
	 BitsPerSample=new byte[]{tmp[0],tmp[1]};
 }
 public static byte[] revers(byte[] tmp){
	 byte[] reversed=new byte[tmp.length];
	 for(int i=0;i		 reversed[i]=tmp[tmp.length-i-1];

	 }
	 return reversed;
 }
 public static byte[] intToBytes(int num){
	 byte[]  bytes=new byte[4];
	 bytes[0]=(byte)(num>>24);
	 bytes[1]=(byte)((num>>16)& 0x000000FF);
	 bytes[2]=(byte)((num>>8)& 0x000000FF);
	 bytes[3]=(byte)(num & 0x000000FF);
	 return bytes;

 }


 public static void main(String[] args){


	InputStream input=capAudio();
	int toaldatasize=0;
	int audiolen;
	byte[] audiochunk=new byte[1024];
//因为文件需要顺序读写，并且只能在最后才能确定riffsize和datasize参数，所以对前面的data要缓存。
	ByteArrayOutputStream bytebuff=new ByteArrayOutputStream(9600000);
	Timer tm=new Timer(20000);
	tm.start();
	try {
		while(isrecording){
			audiolen=input.read(audiochunk);
			toaldatasize+=audiolen;
			 bytebuff.write(audiochunk, 0, audiolen);
		}
	} catch (IOException e1) {
		// TODO Auto-generated catch block
		e1.printStackTrace();
	}

	 	DataSize=revers(intToBytes(toaldatasize));
	RIFF_SIZE=revers(intToBytes(toaldatasize+36-8));
	File wavfile= new File("F:\\writedformdata.wav");
	FileOutputStream file=null;

	 try {
		  file=new FileOutputStream(wavfile);
		  BufferedOutputStream fw=new BufferedOutputStream(file);
		  init();

	fw.write(RIFF);
	fw.write(RIFF_SIZE);
	fw.write(RIFF_TYPE);
	fw.write(FORMAT);
	fw.write(FORMAT_SIZE);
	fw.write(FORMATTAG);
	fw.write(CHANNELS);
	fw.write(SamplesPerSec);
	fw.write(AvgBytesPerSec);
	fw.write(BlockAlign);
	fw.write(BitsPerSample);

	fw.write(DataChunkID);
	fw.write(DataSize);
	fw.write(bytebuff.toByteArray());
	fw.flush();
	 } catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
 }

//这是音频采集的部分。
 public static InputStream capAudio(){
	 float fFrameRate = 16000.0F;
		TargetDataLine target_line = null;
		AudioFormat format = new AudioFormat(AudioFormat.Encoding.PCM_SIGNED,
				fFrameRate, 16, 1, 2, fFrameRate, false);
		DataLine.Info lineInfo = new DataLine.Info(TargetDataLine.class,
				format, 65536);
		try {
			target_line = (TargetDataLine) AudioSystem.getLine(lineInfo);
			target_line.open(format, 655360);

		} catch (LineUnavailableException e) {
			System.err
					.println("ERROR: LineUnavailableException at AudioSender()");
			e.printStackTrace();
		}
		AudioInputStream audio_input = new AudioInputStream(target_line);
		target_line.start();
		isrecording=true;
		return audio_input;
 }

 public void stopRecord(){

 }
}


//Timer 是一个定时线程，到指定时间后将isrecording设置为false从而停止采集音频。

public class Timer extends Thread{

	private int len;
	public Timer(int len_){
		this.len=len_;
	}
	public void run(){
		try {
			Thread.sleep(len);
		} catch (InterruptedException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		SpeechStore.isrecording=false;
	}
}