Problems with jsresources SingleChannelStereoAudioInputStream.java example

Question

I've noticed something quite peculiar with the SingleChannelStereoAudioInputStream.java example. The algorithm seems to be able to place the mono waveform on either the left or right channel (I confirm this using the Adobe Audition waveform display), but instead of leaving the other channel completely silent, it creates a periodic noise spike every other couple of seconds. I've tried this with many mono audio files with the same results. Has anyone else experienced this?
Thanks in advance.

Answer 1

Thanks for the quick reply.
Unfortunately, whether sm_bOptimizeSilenceWriting is set to true or false, the results are the same. I'm not quite sure which array they're referring to when they state: +"This assumes that the array has been filled with 0's outside of this class, which is often the case."+
The only array from the code (*m_abSilenceSample*) that seems to be filled with 0's in this example is the following:
// A silence sample (mono) in byte representation of this stream.
private byte[] m_abSilenceSample;
int nSampleSizeInBytes = getFormat().getFrameSize() / 2;
m_abSilenceSample = new byte[nSampleSizeInBytes];
// For signed PCM representation, the values of the array
// m_abSilenceSample are left with the initial value 0 (this
// represents silence). For unsigned 8 bit, the value 128
// represents silence. Therefore, the (single) byte is
// initialized with this value. Unsigned formats with more
// than 8 bits are not supported.
if (getFormat().getEncoding().equals(AudioFormat.Encoding.PCM_UNSIGNED)) {
   if (getFormat().getSampleSizeInBits() == 8) {
      m_abSilenceSample[0] = (byte) 128;
   } else {
      throw new IllegalArgumentException("unsigned formats are only supported for 8 bit");
}Unfortunately, it doesn't seem to be used in the read() portion of the code.