int count = GetAudioCapture(APTR handle, APTR buffer, int size);
HWEXT_AUDIOADAPTER_CAPTURE
extension bit has been set. See Extension plugins for details. In that case, it
must copy PCM samples from the buffer of the audio capture specified by handle to the
memory buffer passed in the buffer parameter. The size of the buffer in bytes will be
passed to this function in the size parameter. You may copy up to size bytes to the
buffer specified by buffer. The handle parameter is a handle allocated by the StartAudioCapture()
function.
Your implementation of GetAudioCapture() must return the number of bytes actually copied
to the memory buffer specified in buffer. It's absolutely allowed to return 0 in case
there are currently no samples that can be copied to the buffer. If that is the case,
just return 0. Hollywood will then call GetAudioCapture() again until there are samples
to be copied.