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问java pcm转wav
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Stack Overflow用户

提问于 2010-12-14 14:09:53

回答 5查看 10.3K关注 0票数 4

我有一个pcm文件，我想把它转换成wav文件。

有没有合适的api或代码来做这件事？

java

wav

pcm

回答 5

Stack Overflow用户

发布于 2013-08-28 14:03:17

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: 2016-01-11

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;
}

票数 7

Stack Overflow用户

发布于 2016-07-29 05:33:11

这应该很容易做到，因为WAV = Metadata + PCM (按照这个顺序)。这应该是可行的：

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

它使用起来非常简单。就像这样叫它：

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();
}

这一切是如何工作的

如您所见，WAV报头是WAV和PCM文件格式之间的唯一区别。假设您正在录制16位PCM单声道音频(根据您的代码，您是)。rawToWave函数只是巧妙地向WAV文件添加了头文件，以便音乐播放器知道在打开文件时会发生什么，然后在头文件之后，它只是从最后一位开始写入PCM数据。

Cool Tip

如果你想改变你声音的音调，或者制作一个变音应用，你所要做的就是增加/减少代码中writeInt(output, 44100); // sample rate的值。减少它将告诉玩家以不同的速率播放它，从而改变输出音高。只是一点额外的“很高兴知道”的事情。:)

票数 4

Stack Overflow用户

发布于 2018-03-23 21:22:19

我还不能发表评论，但请注意，devflow答案中的get16BitPcm方法正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;
}