在我们开发中，会遇到pcm格式的音频转为wav，下面讲解一下具体怎么实现：
第一步：pcm文件转wav文件
/*** pcm文件转wav文件** @param inFilename 源文件路径* @param outFilename 目标文件路径* @param deleteOrg 是否删除源文件*/
public void pcmToWav(String inFilename, String outFilename, boolean deleteOrg) {FileInputStream in;FileOutputStream out;long totalAudioLen;long totalDataLen;long longSampleRate = mSampleRate;int channels = 2;long byteRate = 16 * mSampleRate * channels / 8;byte[] data = new byte[mBufferSize];try {in = new FileInputStream(inFilename);out = new FileOutputStream(outFilename);totalAudioLen = in.getChannel().size();totalDataLen = totalAudioLen + 36;writeWaveFileHeader(out, totalAudioLen, totalDataLen,longSampleRate, channels, byteRate);while (in.read(data) != -1) {out.write(data);}in.close();out.close();if (deleteOrg) {new File(inFilename).delete();}} catch (IOException e) {e.printStackTrace();}
}
第二步：加入wav文件头
/* * 加入wav文件头*/
private void writeWaveFileHeader(FileOutputStream out, long totalAudioLen,long totalDataLen, long longSampleRate, int channels, long byteRate)throws IOException {byte[] header = new byte[44];header[0] = 'R'; // RIFF/WAVE headerheader[1] = 'I';header[2] = 'F';header[3] = 'F';header[4] = (byte) (totalDataLen & 0xff);header[5] = (byte) ((totalDataLen >> 8) & 0xff);header[6] = (byte) ((totalDataLen >> 16) & 0xff);header[7] = (byte) ((totalDataLen >> 24) & 0xff);header[8] = 'W'; //WAVEheader[9] = 'A';header[10] = 'V';header[11] = 'E';header[12] = 'f'; // 'fmt ' chunkheader[13] = 'm';header[14] = 't';header[15] = ' ';header[16] = 16; // 4 bytes: size of 'fmt ' chunkheader[17] = 0;header[18] = 0;header[19] = 0;header[20] = 1; // format = 1header[21] = 0;header[22] = (byte) channels;header[23] = 0;header[24] = (byte) (longSampleRate & 0xff);header[25] = (byte) ((longSampleRate >> 8) & 0xff);header[26] = (byte) ((longSampleRate >> 16) & 0xff);header[27] = (byte) ((longSampleRate >> 24) & 0xff);header[28] = (byte) (byteRate & 0xff);header[29] = (byte) ((byteRate >> 8) & 0xff);header[30] = (byte) ((byteRate >> 16) & 0xff);header[31] = (byte) ((byteRate >> 24) & 0xff);header[32] = (byte) (2 * 16 / 8); // block alignheader[33] = 0;header[34] = 16; // bits per sampleheader[35] = 0;header[36] = 'd'; //dataheader[37] = 'a';header[38] = 't';header[39] = 'a';header[40] = (byte) (totalAudioLen & 0xff);header[41] = (byte) ((totalAudioLen >> 8) & 0xff);header[42] = (byte) ((totalAudioLen >> 16) & 0xff);header[43] = (byte) ((totalAudioLen >> 24) & 0xff);out.write(header, 0, 44);
}
下面附上全部的代码，写成相对应的工具类：
public class PcmToWavUtil {private int mBufferSize; //缓存的音频大小private int mSampleRate = 44100;// 此处的值必须与录音时的采样率一致private int mChannel = AudioFormat.CHANNEL_IN_STEREO; //立体声private int mEncoding = AudioFormat.ENCODING_PCM_16BIT;private static class SingleHolder {static PcmToWavUtil mInstance = new PcmToWavUtil();}public static PcmToWavUtil getInstance() {return SingleHolder.mInstance;}public PcmToWavUtil() {this.mBufferSize = AudioRecord.getMinBufferSize(mSampleRate, mChannel, mEncoding);}/*** @param sampleRate sample rate、采样率* @param channel channel、声道* @param encoding Audio data format、音频格式*/public PcmToWavUtil(int sampleRate, int channel, int encoding) {this.mSampleRate = sampleRate;this.mChannel = channel;this.mEncoding = encoding;this.mBufferSize = AudioRecord.getMinBufferSize(mSampleRate, mChannel, mEncoding);}/*** pcm文件转wav文件** @param inFilename 源文件路径* @param outFilename 目标文件路径* @param deleteOrg 是否删除源文件*/public void pcmToWav(String inFilename, String outFilename, boolean deleteOrg) {FileInputStream in;FileOutputStream out;long totalAudioLen;long totalDataLen;long longSampleRate = mSampleRate;int channels = 2;long byteRate = 16 * mSampleRate * channels / 8;byte[] data = new byte[mBufferSize];try {in = new FileInputStream(inFilename);out = new FileOutputStream(outFilename);totalAudioLen = in.getChannel().size();totalDataLen = totalAudioLen + 36;writeWaveFileHeader(out, totalAudioLen, totalDataLen,longSampleRate, channels, byteRate);while (in.read(data) != -1) {out.write(data);}in.close();out.close();if (deleteOrg) {new File(inFilename).delete();}} catch (IOException e) {e.printStackTrace();}}public void pcmToWav(String inFilename, String outFilename) {pcmToWav(inFilename, outFilename, false);}/*** 加入wav文件头*/private void writeWaveFileHeader(FileOutputStream out, long totalAudioLen,long totalDataLen, long longSampleRate, int channels, long byteRate)throws IOException {byte[] header = new byte[44];header[0] = 'R'; // RIFF/WAVE headerheader[1] = 'I';header[2] = 'F';header[3] = 'F';header[4] = (byte) (totalDataLen & 0xff);header[5] = (byte) ((totalDataLen >> 8) & 0xff);header[6] = (byte) ((totalDataLen >> 16) & 0xff);header[7] = (byte) ((totalDataLen >> 24) & 0xff);header[8] = 'W'; //WAVEheader[9] = 'A';header[10] = 'V';header[11] = 'E';header[12] = 'f'; // 'fmt ' chunkheader[13] = 'm';header[14] = 't';header[15] = ' ';header[16] = 16; // 4 bytes: size of 'fmt ' chunkheader[17] = 0;header[18] = 0;header[19] = 0;header[20] = 1; // format = 1header[21] = 0;header[22] = (byte) channels;header[23] = 0;header[24] = (byte) (longSampleRate & 0xff);header[25] = (byte) ((longSampleRate >> 8) & 0xff);header[26] = (byte) ((longSampleRate >> 16) & 0xff);header[27] = (byte) ((longSampleRate >> 24) & 0xff);header[28] = (byte) (byteRate & 0xff);header[29] = (byte) ((byteRate >> 8) & 0xff);header[30] = (byte) ((byteRate >> 16) & 0xff);header[31] = (byte) ((byteRate >> 24) & 0xff);header[32] = (byte) (2 * 16 / 8); // block alignheader[33] = 0;header[34] = 16; // bits per sampleheader[35] = 0;header[36] = 'd'; //dataheader[37] = 'a';header[38] = 't';header[39] = 'a';header[40] = (byte) (totalAudioLen & 0xff);header[41] = (byte) ((totalAudioLen >> 8) & 0xff);header[42] = (byte) ((totalAudioLen >> 16) & 0xff);header[43] = (byte) ((totalAudioLen >> 24) & 0xff);out.write(header, 0, 44);}}
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