使用TargetDataLine来获取实时音频：缓冲区不变

Question

I have some code like this:

  byte tempBuffer[] = new byte[10000];

  //call sleep thread (how long specified by second parameter)
  //After sleep time is up it sets stopCapture to true
  AudioSleepThread ast = new AudioSleepThread(this, seconds);
  ast.start();

  while(!this.stopCapture) {
    //this method blocks
    int cnt = targetDataLine.read(tempBuffer, 0, tempBuffer.length);
    System.out.println(cnt);
    if (cnt>0) {
          // Subsequent requests must **only** contain the audio data.
          RequestThread reqt = new RequestThread(responseObserver, requestObserver, tempBuffer);
          reqt.start();
          //Add it to array list
          this.reqtArray.add(reqt);
    }
  }

I have a tempBuffer, in which I store 10000 bytes at a time. Each time I have 10000 bytes worth of audio, I send it along a request thread to process this chunk of audio. My problem is that I keep sending the same buffer with the same audio to every single one of my request threads.

In my mind, what is supposed to happen is that targetDataLine will read the audio 10000 bytes at a time and pass each of tempBuffers containing different parts of my audio to each of my request threads.

Perhaps I have misunderstood TargetDataLine.

Answer 1

You are only creating tempBuffer once, outside of your loop. Each call to targetDataLine.read is overwriting the contents of the buffer with the new data. Unless you are copying the buffer in the RequestThread constructor this will cause problems. You should proably create a new buffer for each read:

while(!this.stopCapture) {
  byte tempBuffer[] = new byte[10000];
  //this method blocks
  int cnt = targetDataLine.read(tempBuffer, 0, tempBuffer.length);

You must also take notice of the number of bytes read returned by the read (your cnt variable). The read does not guarantee to fill the buffer.