Question

我正在收听实时电话，并且能够获得原始PCM字节。我也能通过java的音频api听这些字节。这些都适用于小程序。

现在我希望能够将电话呼叫的原始PCM字节转换为WAV字节，以便我可以将其直接写入ServletOutputStream。这将允许浏览器实际收听电话。

有没有人知道我怎么能在运行中将一些原始PCM字节[]转换为WAV字节[]？

我见过的例子都与将文件转换为另一个文件有关。

java pcm to wav

How can I write a WAV file from byte array in java?

谢谢。

Answer 1

我也陷入了同样的境地，这就是我如何解决问题的方法。

public static boolean getWavFile(String filePath, InputStream audioStream) throws IOException {

    boolean result = false;
    try {

        byte[] decodedData = IOUtils.toByteArray(audioStream);

        System.out.println(">>Decoded Data" + Arrays.toString(decodedData));
        File outFile = new File(filePath);
        AudioFormat format = new AudioFormat(8000, 16, 1, true, false);
        AudioSystem.write(new AudioInputStream(new ByteArrayInputStream(
                decodedData), format, decodedData.length), AudioFileFormat.Type.WAVE, outFile);
        result = true;
        return result;
    } catch (IOException ex) {
        System.out.println("<<getWavFile - impl" + ex);
        return result;

    }
}

Answer 2

已经有一段时间了，但我认为这可能会对某人有所帮助。这是我的解决方案-我将字节写回到任何输出流（在我的情况下是servletoutputstream）。首先，我写入WAV标头（44字节）以输出流并写入pcm字节（您需要将pcm数据转换为字节数组）。我在html中使用了音频标签，并指定了src标签作为我的api网址，并且效果很好。

public void streamCloudObject(OutputStream stream, InputStream pcmData) throws IOException {

    stream.write(WAVHeader.build(44100,5242880));
    //byte_chunk_size is stream buffer size, I have it as 1MB, so at a time you are streaming 1MB of bytes
    byte[] outBytes = new byte[BYTE_CHUNK_SIZE];

    while(true) {   
        int r = pcmData.read(outBytes);
        if(r == -1)
            break;      
        stream.write(outBytes,0,r); 

    }

}


public class WAVHeader {

private static final int CHUNK_SIZE = 36;
private static final int BIT_RATE_16 = 16;
private static final int MONO = 1;
private static final int HEADER_SIZE = 44;

//inputStreamLength - I send the pcm filesize here and I get it from s3.
public static byte[] build(int sampleRate,int inputStreamLength) {

    byte[] header = new byte[HEADER_SIZE];
    int srate = resp.getSampleRate();
    int channel = MONO;
    int format = BIT_RATE_16;
    long dataLength = inputStreamLength;

    long totalDataLen = dataLength + CHUNK_SIZE;
    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) (dataLength  & 0xff);
    header[41] = (byte) ((dataLength >> 8) & 0xff);
    header[42] = (byte) ((dataLength >> 16) & 0xff);
    header[43] = (byte) ((dataLength >> 24) & 0xff);
    return header;
}
}

将PCM原始字节转换为WAV字节

2 个答案: