Java把V3音频文件转化为wav文件的算法

Java把V3音频文件转化为wav文件的算法
来源：http://www.oschina.net/code/snippet_855150_14739

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import org.apache.commons.net.ftp.FTPClient;
import org.apache.commons.net.ftp.FTPClientConfig;
import org.apache.commons.net.ftp.FTPFile;
import com.eshore.ccf.CCFLogger;
public class V3FileUtil {
	private String voxfreq = "6000";
	public V3FileUtil() {
	}
	
	public void long2Byte(byte[] output, long[] input, int len) {
		int i, j;
		for (i = 0, j = 0; j < len; i++, j += 4) {
			output[j] = (byte) (input[i] & 0xffL);
			output[j + 1] = (byte) ((input[i] >>> 8) & 0xffL);
			output[j + 2] = (byte) ((input[i] >>> 16) & 0xffL);
			output[j + 3] = (byte) ((input[i] >>> 24) & 0xffL);
		}
	}
	public void short2Byte(byte[] output, short sh) {
		output[0] = (byte) (sh & 0xffL);
		output[1] = (byte) ((sh >>> 8) & 0xffL);
	}
	public short byte2Short(byte b) {
		return b < 0 ? (short) (b & 0x7F + 128) : b;
	}
	public void convert(String v3File , String wavFile) throws Exception{
		BufferedInputStream fileInput = null;
		BufferedOutputStream fileOut = null;
		int[] indsft = { -1, -1, -1,-1, 2, 4, 6, 8 };
		int[] stpsz = { 16, 17, 19, 21, 23, 25, 28, 31, 34, 37, 41, 45, 50, 55,
				60, 66, 73, 80, 88, 97, 107, 118, 130, 143, 157, 173, 190, 209,
				230, 253, 279, 307, 337, 371, 408, 449, 494, 544, 598, 658,
				724, 796, 876, 963, 1060, 1166, 1282, 1411, 1552, 1707, 1878,
				2066, 2272, 2499, 2749, 3024, 3327, 3660, 4026, 4428, 4871,
				5358, 5894, 6484, 7132, 7845, 8630, 9493, 10442, 11487, 12635,
				13899, 15289, 16818, 18500, 20350, 22385, 24623, 27086, 29794 };
		/* nibble to bit map */
		int nbl2bit[][] = { { 0, 0, 0, 0 }, { 0, 0, 0, 1 }, { 0, 0, 1, 0 },
				{ 0, 0, 1, 1 }, { 0, 1, 0, 0 }, { 0, 1, 0, 1 }, { 0, 1, 1, 0 },
				{ 0, 1, 1, 1 }, { 1, 0, 0, 0 }, { 1, 0, 0, 1 }, { 1, 0, 1, 0 },
				{ 1, 0, 1, 1 }, { 1, 1, 0, 0 }, { 1, 1, 0, 1 }, { 1, 1, 1, 0 },
				{ 1, 1, 1, 1 } };
		/* sign table */
		int sgns[] = { 1, -1 };
		File file = new File(v3File);
		/* step size index */
		int ssindex = 0;
			if(file == null) {
				CCFLogger.logger.info("没有找到文件:" + v3File);
				return ;
			}
			
			fileInput = new BufferedInputStream(new FileInputStream(file));
			fileOut = new BufferedOutputStream (new FileOutputStream(wavFile));
			long lPCMHDR[] = { 0x46464952, 0, 0x45564157, 0x20746d66, 16,
					0x10001, 0, 0, 0x100002, 0x61746164, 0 };
			lPCMHDR[1] = 4 * file.length() + 0x30; // 文件长度
			lPCMHDR[6] = Integer.parseInt(voxfreq);
			lPCMHDR[7] = 2 * Integer.parseInt(voxfreq);
			lPCMHDR[10] = 4 * file.length();
			// 先写一个头
			byte[] b = new byte[44];
			long2Byte(b, lPCMHDR, 44);
			fileOut.write(b, (int) 0, b.length);
			short iVal = 0;
			int pos = 0;
			byte[] szBuf = new byte[128 * 1024];
			int diff;
			short incoded;
			byte[] szDesBuf = new byte[4 * 128 * 1024];
			int dwRead = 0;
			
			while ((dwRead = fileInput.read(szBuf, 0, 128 * 1024))!= -1) {
				for (int idx = 0; idx < dwRead - 1; idx++) {
					incoded = (short) (byte2Short(szBuf[idx]) / 16);
					diff = sgns[nbl2bit[incoded][0]]
							* (stpsz[ssindex] * nbl2bit[incoded][1]
									+ (stpsz[ssindex] / 2)
									* nbl2bit[incoded][2]
									+ (stpsz[ssindex] / 4)
									* nbl2bit[incoded][3] + (stpsz[ssindex] / 8));
					ssindex = ssindex + indsft[(incoded % 8)];
					if (ssindex < 0)
						ssindex = 0;
					if (ssindex > 48)
						ssindex = 48;
					iVal += diff;
					if (iVal > 2047)
						iVal = 2047;
					else if (iVal < -2047)
						iVal = -2047;
					
					byte[] b2 = new byte[2];
					short2Byte(b2, (short) (iVal * 16));
					szDesBuf[pos] = b2[0];
					pos++;
					szDesBuf[pos] = b2[1];
					pos++;
					
					// /////////////////////////////////////////////////
					incoded = (short) (byte2Short(szBuf[idx]) % 16);
					diff = sgns[nbl2bit[incoded][0]]
							* (stpsz[ssindex] * nbl2bit[incoded][1]
									+ (stpsz[ssindex] / 2)
									* nbl2bit[incoded][2]
									+ (stpsz[ssindex] / 4)
									* nbl2bit[incoded][3] + (stpsz[ssindex] / 8));
					ssindex = ssindex + indsft[(incoded % 8)];
					if (ssindex < 0)
						ssindex = 0;
					if (ssindex > 48)
						ssindex = 48;
					iVal += diff;
					//波长
					if (iVal > 2047)
						iVal = 2047;
					else if (iVal < -2047)
						iVal = -2047;
					byte[] b3 = new byte[2];
					short2Byte(b3, (short) (iVal * 16));
					szDesBuf[pos] = b3[0];
					pos++;
					szDesBuf[pos] = b3[1];
					pos++;
				}
				try {
					fileOut.write(szDesBuf, 0,  dwRead * 4 );
					fileOut.flush();
				} catch (Exception e) {
					CCFLogger.logger.error("转换文件失败！", e);
				}
				pos = 0;
			}
			CCFLogger.logger.error("转换文件到wav成功.......................");
			try {
				if (fileInput != null) fileInput.close();
				if (fileOut != null) fileOut.close();
			} catch (IOException e) {}
			return ;
	}
}