我有一个pcm文件，想将其转换为wav文件。
是否有适合的API或代码可以实现这一功能？
5个回答
8
这是我的代码
/**
* Write PCM data as WAV file
* @param os Stream to save file to
* @param pcmdata 8 bit PCMData
* @param srate Sample rate - 8000, 16000, etc.
* @param channel Number of channels - Mono = 1, Stereo = 2, etc..
* @param format Number of bits per sample (16 here)
* @throws IOException
*/
public void PCMtoFile(OutputStream os, short[] pcmdata, int srate, int channel, int format) throws IOException {
byte[] header = new byte[44];
byte[] data = get16BitPcm(pcmdata);
long totalDataLen = data.length + 36;
long bitrate = srate * channel * format;
header[0] = 'R';
header[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';
header[9] = 'A';
header[10] = 'V';
header[11] = 'E';
header[12] = 'f';
header[13] = 'm';
header[14] = 't';
header[15] = ' ';
header[16] = (byte) format;
header[17] = 0;
header[18] = 0;
header[19] = 0;
header[20] = 1;
header[21] = 0;
header[22] = (byte) channel;
header[23] = 0;
header[24] = (byte) (srate & 0xff);
header[25] = (byte) ((srate >> 8) & 0xff);
header[26] = (byte) ((srate >> 16) & 0xff);
header[27] = (byte) ((srate >> 24) & 0xff);
header[28] = (byte) ((bitrate / 8) & 0xff);
header[29] = (byte) (((bitrate / 8) >> 8) & 0xff);
header[30] = (byte) (((bitrate / 8) >> 16) & 0xff);
header[31] = (byte) (((bitrate / 8) >> 24) & 0xff);
header[32] = (byte) ((channel * format) / 8);
header[33] = 0;
header[34] = 16;
header[35] = 0;
header[36] = 'd';
header[37] = 'a';
header[38] = 't';
header[39] = 'a';
header[40] = (byte) (data.length & 0xff);
header[41] = (byte) ((data.length >> 8) & 0xff);
header[42] = (byte) ((data.length >> 16) & 0xff);
header[43] = (byte) ((data.length >> 24) & 0xff);
os.write(header, 0, 44);
os.write(data);
os.close();
}
编辑：2016年01月11日
public byte[] get16BitPcm(short[] data) {
byte[] resultData = new byte[2 * data.length];
int iter = 0;
for (double sample : data) {
short maxSample = (short)((sample * Short.MAX_VALUE));
resultData[iter++] = (byte)(maxSample & 0x00ff);
resultData[iter++] = (byte)((maxSample & 0xff00) >>> 8);
}
return resultData;
}
- devflow
3
4
这应该很容易做到，因为WAV = 元数据 + PCM（按顺序）。以下方法可行：
private void rawToWave(final File rawFile, final File waveFile) throws IOException {
byte[] rawData = new byte[(int) rawFile.length()];
DataInputStream input = null;
try {
input = new DataInputStream(new FileInputStream(rawFile));
input.read(rawData);
} finally {
if (input != null) {
input.close();
}
}
DataOutputStream output = null;
try {
output = new DataOutputStream(new FileOutputStream(waveFile));
// WAVE header
// see http://ccrma.stanford.edu/courses/422/projects/WaveFormat/
writeString(output, "RIFF"); // chunk id
writeInt(output, 36 + rawData.length); // chunk size
writeString(output, "WAVE"); // format
writeString(output, "fmt "); // subchunk 1 id
writeInt(output, 16); // subchunk 1 size
writeShort(output, (short) 1); // audio format (1 = PCM)
writeShort(output, (short) 1); // number of channels
writeInt(output, 44100); // sample rate
writeInt(output, RECORDER_SAMPLERATE * 2); // byte rate
writeShort(output, (short) 2); // block align
writeShort(output, (short) 16); // bits per sample
writeString(output, "data"); // subchunk 2 id
writeInt(output, rawData.length); // subchunk 2 size
// Audio data (conversion big endian -> little endian)
short[] shorts = new short[rawData.length / 2];
ByteBuffer.wrap(rawData).order(ByteOrder.LITTLE_ENDIAN).asShortBuffer().get(shorts);
ByteBuffer bytes = ByteBuffer.allocate(shorts.length * 2);
for (short s : shorts) {
bytes.putShort(s);
}
output.write(fullyReadFileToBytes(rawFile));
} finally {
if (output != null) {
output.close();
}
}
}
byte[] fullyReadFileToBytes(File f) throws IOException {
int size = (int) f.length();
byte bytes[] = new byte[size];
byte tmpBuff[] = new byte[size];
FileInputStream fis= new FileInputStream(f);
try {
int read = fis.read(bytes, 0, size);
if (read < size) {
int remain = size - read;
while (remain > 0) {
read = fis.read(tmpBuff, 0, remain);
System.arraycopy(tmpBuff, 0, bytes, size - remain, read);
remain -= read;
}
}
} catch (IOException e){
throw e;
} finally {
fis.close();
}
return bytes;
}
private void writeInt(final DataOutputStream output, final int value) throws IOException {
output.write(value >> 0);
output.write(value >> 8);
output.write(value >> 16);
output.write(value >> 24);
}
private void writeShort(final DataOutputStream output, final short value) throws IOException {
output.write(value >> 0);
output.write(value >> 8);
}
private void writeString(final DataOutputStream output, final String value) throws IOException {
for (int i = 0; i < value.length(); i++) {
output.write(value.charAt(i));
}
}
如何使用
使用起来非常简单。只需像这样调用它：
File f1 = new File("/sdcard/44100Sampling-16bit-mono-mic.pcm"); // The location of your PCM file
File f2 = new File("/sdcard/44100Sampling-16bit-mono-mic.wav"); // The location where you want your WAV file
try {
rawToWave(f1, f2);
} catch (IOException e) {
e.printStackTrace();
}
工作原理
可以看到，WAV头是WAV和PCM文件格式之间唯一的区别。假设你正在录制16位PCM MONO音频（根据你的代码，你是这样做的）。rawToWave函数只是将头文件整齐地添加到WAV文件中，以便音乐播放器在打开文件时知道该期望什么，然后在头文件之后，它只会从最后一位开始写入PCM数据。
小提示
如果您想改变声音的音高或制作声音变换应用程序，您只需要增加/减少代码中的writeInt(output, 44100); // sample rate的值。将其减小会告诉播放器以不同速率播放，从而改变输出音高。这只是一个额外的“好知道”的东西。:)
- Advait Saravade
2
我还不能留下评论，但请注意devflow回答中的get16BitPcm方法在[奇怪地]缩放输入数据。如果您已经有16位pcm数据要写入wav文件，则该方法应该如下所示：
public byte[] get16BitPcm(short[] data) {
byte[] resultData = new byte[2 * data.length];
int iter = 0;
for (short sample : data) {
resultData[iter++] = (byte)(sample & 0x00ff);
resultData[iter++] = (byte)((sample & 0xff00) >>> 8);
}
return resultData;
}
- wolf1oo
0
我知道一个叫做"OperateWav"的工具，我曾在我的第一个实习项目中使用它来开发一个转换器（Linux C / C ++）。我不确定这个工具是否真正存在，以及它是否支持Java。实际上，WAV文件只是在PCM原始数据上添加了一个WAV格式头...
- jasonkim
网页内容由stack overflow 提供, 点击上面的可以查看英文原文，
原文链接
原文链接
get16BitPcm(short[])函数是否只是将一个byte[]的大小扩大两倍？如果是，它的字节序是什么？如果不是，它是做什么用的？ - Scruffy