[wdmaudiodev] Windows usbaudio.sys architecture question

  • From: Bartosik Lukasz-ALB045 <lukasz.bartosik@xxxxxxxxxxxxxxxxxxxxx>
  • To: "wdmaudiodev@xxxxxxxxxxxxx" <wdmaudiodev@xxxxxxxxxxxxx>
  • Date: Mon, 10 Sep 2012 12:52:30 +0000


We are developing USB audio device which will use generic usbaudio.sys driver 
provided by Windows 7.

The device's USB descriptors define 5 input mono terminals (2 headsets, 1 
microphone, 2 lines in) which use one isochronous IN USB endpoint to transport 
audio data from the device to Windows OS.

When the device is connected, Windows reports 5 recording devices. What is a 
bit surprising to me is that each of the 5 recording devices has 5 channels and 
can be used to receive data from all 5 channels. What's more when one of the 
five devices is being used to receive audio data then an attempt to use other 
device ends with an error message "device already in use".

Our device has the following topology (captured with ksstudio.exe):


Basically everything works fine and I'm just looking for confirmation whether 
the behavior described above is expected or are we using Windows' audio 
architecture in a way it was not designed (I mean we are misusing it) ?



JPEG image

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