Hi, I am not sure if it has been already discussed. I searched but did not get some thing real worth. I am do not have any experience in audio driver development. But I need to develop an virtual audio driver which will simply buffer audio data that is being played in your system. I have looked into MSVAD example available in WDK. But I am confused which one should I choose ac3,pcmex........ or which one actually suffice my requirement. Any pointer or any hint will help a lot.