[wdmaudiodev] Few questions about core Audio APIs in Vista

  • From: Andrew Mindrin <wdmaudiodev@xxxxxxxxxxxxxxxxxx>
  • To: wdmaudiodev@xxxxxxxxxxxxx
  • Date: Fri, 1 Dec 2006 11:09:13 +0400


The questions are:

Q1. Enumerating all audio sessions
I need to enumerate all audio sessions in Vista to take control over
them like Sndvol.exe. Is there a way? I need that to create custom
volume control software.

I've tried to play with WASAPI, but it is possible only to create new
session or to open a sessions of current process created by high-level

Q2. Volume levels in Vista
I've noticed that some sound drivers for Vista doesn't support precise
volume setup. E.g. with the latest driver from Creative (2.11.0000) when
I set volume by using IAudioVolumeLevel::SetLevel to e.g. -5.02 dB and
then has read it by using IAudioVolumeLevel::GetLevel, the result is -5
dB instead of -5.02 dB. Is this driver bug or volume level in Vista can
be set\read only with a step returned by GetLevelRange method (pfStepping
parameter)? If this is not a bug, how to set\read precise levels?

Many thanks,


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