[wdmaudiodev] AVStream minidriver Capture stream fails WASAPI Exclusive-mode Stream

  • From: "Dale Hill" <daleh@xxxxxxxxxxxxxxxxxxxxxxx>
  • To: <wdmaudiodev@xxxxxxxxxxxxx>
  • Date: Tue, 27 May 2014 10:13:38 -0600


We are unable to access capture streams using a WASAPI application in


We've developed a virtual audio driver based on the AVStream mini-driver
model. It's been around for awhile and at this point works pretty well.
Recently however we've been trying to access capture streams using a WASAPI
application in exclusive-mode (AUDCLNT_SHAREMODE_EXCLUSIVE). This seems to
work just fine on 32-bit Windows 7 but on 64-bit Windows 7,
IsFormatSupported fails with error AUDCLNT_E_UNSUPPORTED_FORMAT


A few things worth noting:

IsFormatSupported() works fine on 64-bit Windows 7 when ShareMode is set to

The driver only supports one format: 48KHz, 24bit, PCM. 

We're working with 64-bit Windows 7, SP1. 


I don't believe that the driver has anything to do with enable
exclusive-mode. Could someone please confirm that - one way or another?


Does anyone have any ideas or information on this?


Thanks in advance.





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