Wrong file/data size in Wave Header

Question

Hi all,
I record audio from the Mic into a byteArrayOutputStream and afterwards like to store it in a file. This is the main code:
     private void sendAudio() {
               byte audioData[] = byteArrayOutputStream.toByteArray();
               AudioInputStream ais = new AudioInputStream(new ByteArrayInputStream(audioData), getAudioFormat(), audioData.length);
               File file = new File("d:\\test.wav");
               AudioSystem.write(ais, AudioFileFormat.Type.WAVE, file);
     private AudioFormat getAudioFormat() {
          float sampleRate = 8000.0F;
          int sampleSizeInBits = 16;
          int channels = 1;
          boolean signed = true;
          boolean bigEndian = false;
          return new AudioFormat(sampleRate, sampleSizeInBits, channels, signed, bigEndian);
     }If i use a sampleSize of 8bits the generated wave file is fine. But when I use 16bit the size specified in the riff chunk and data chunk is wrong. It is twice the size it should be. I looked it up in the source code and it looks like the calculated sizes are mulitplied with the number of bytes of one sample. This works fine for 8 bits (num=1) but doesn't work for 16 bits (num=2).
Windows Media Player refuses to play the 16bit wav file. After correcting the size values (basically dividing the size without header by 2) the files are played fine.
Is it a bug in the WaveFileWriter Implementation or did I forget to specify a parameter somewhere.
Any help appreciated,
Jan

Answer 1

I found it.
You need to specify the number of samples when construction the AudioInputStream. I passed the length of the audioData, which is wrong:
//wrong
AudioInputStream ais = new AudioInputStream(new ByteArrayInputStream(audioData), getAudioFormat(), audioData.length);
/right
AudioInputStream ais = new AudioInputStream(new ByteArrayInputStream(audioData), getAudioFormat(), audioData.length / (sampleRate / 8) );