That is a policy implemented within the Windows audio system. Sent from Windows Mail on my Surface Pro From: Tim Roberts<mailto:timr@xxxxxxxxx> Sent: ?Friday?, ?August? ?16?, ?2013 ?4?:?45? ?PM To: wdmaudiodev@xxxxxxxxxxxxx<mailto:wdmaudiodev@xxxxxxxxxxxxx> Andrew Sha...... wrote: Hardware-Offloaded Audio Processing http://msdn.microsoft.com/en-us/library/windows/hardware/dn302038(v=vs.85).aspx<http://msdn.microsoft.com/en-us/library/windows/hardware/dn302038%28v=vs.85%29.aspx> So how to discover offloaded formats? There are some fascinating things on that page. This paragraph near the bottom stands out: The functionality described for this new type of audio adapter and its associated driver, can be used by Windows Store apps via WASAPI, Media Foundation, Media Engine, or the HTML 5 <audio> tags. Note that Wave and DSound cannot be used, as they are not available to Windows Store apps. Also note that Classic Win32 applications cannot use adapters that are capable of processing hardware-offloaded audio. How can there possibly be a feature set that is available to Windows Store applications, but NOT to Win32 applications? Win32 applications can access WASAPI and Media Foundation just fine. -- Tim Roberts, timr@xxxxxxxxx<mailto:timr@xxxxxxxxx> Providenza & Boekelheide, Inc.