尝试将原始PCM写入WAV并且仅获取标头

Question

I am currently using this code:

File wavFile=new File("tmp"+File.separator+"recordings"+File.separator+uuid.toString()+".wav");
try{
    FileInputStream pcmInputStream=new FileInputStream(file);
    FileOutputStream wavOutputStream=new FileOutputStream(wavFile);
    AudioSystem.write(new AudioInputStream(new ByteArrayInputStream(IOUtils.toByteArray(pcmInputStream)),
    new AudioFormat(48000,16,2,true,
    true),IOUtils.toByteArray(pcmInputStream).length/4),
    AudioFileFormat.Type.WAVE,wavOutputStream);
    wavOutputStream.flush();
    wavOutputStream.close();
    pcmInputStream.close();
    fileOutputStream.close();
}catch(IOException e){
    e.printStackTrace();
}

Having checked, I can confirm that the PCM has 30 seconds of data and is approximately 4.7MB. This writes the .wav file however it is only 44 bytes and not playable, I reckon that this 44 bytes is the RIFF header but am unsure of how to solve it. I have tried using different lengths and different combinations of File/ByteArray OutputStreams.

Answer 1

When creating the AudioInputStream , you call IOUtils.toByteArray(pcmInputStream) twice, and on the second call, the input stream is already advanced to the end, so toByteArray returns an empty array. This results in 0 getting passed as the argument to the AudioInputStream constructor's length.

new AudioInputStream(
    new ByteArrayInputStream( IOUtils.toByteArray(pcmInputStream) ),
    new AudioFormat(48000,16,2,true,true),
    ( IOUtils.toByteArray(pcmInputStream) ).length/4
)

You should save the byte array to a temporary variable instead of trying to call toByteArray twice on the same input stream.