[wdmaudiodev] Re: Audio AGC?
- From: Matthew van Eerde <Matthew.van.Eerde@xxxxxxxxxxxxx>
- To: "wdmaudiodev@xxxxxxxxxxxxx" <wdmaudiodev@xxxxxxxxxxxxx>
- Date: Wed, 19 Dec 2012 23:06:36 +0000
Yes, that would cause Windows to use your KSPROPERTY_AUDIO_VOLUMELEVEL instead
of injecting a software volume APO, yes. You would then control the default
volume, as well as the min/max/step size. This is usually used to control a
hardware amplifier below the driver; it is not meant to enable kernel-mode
digital signal processing, which is risky and entails floating-point state
recovery etc.
Perhaps a simpler option is to change your pin category to something
non-microphone-ish.
The article says “Of course, the INF file that installs an audio adapter driver
can override the operating system's default volume settings with its own
default settings” but I don’t know details, or even whether that is still true.
From: wdmaudiodev-bounce@xxxxxxxxxxxxx
[mailto:wdmaudiodev-bounce@xxxxxxxxxxxxx] On Behalf Of Tim Roberts
Sent: Wednesday, December 19, 2012 2:51 PM
To: wdmaudiodev@xxxxxxxxxxxxx
Subject: [wdmaudiodev] Re: Audio AGC?
Matthew van Eerde wrote:
What version of Windows are you running on?
See the chart here:
http://msdn.microsoft.com/en-us/library/windows/hardware/ff536251(v=vs.85).aspx<http://msdn.microsoft.com/en-us/library/windows/hardware/ff536251%28v=vs.85%29.aspx>
That's the key reference point I was missing -- enormous thanks for that.
I'm currently testing on Win 7, as is the client. I do advertise myself as a
microphone, so the system is applying a +30dB boost. So, am I right in
thinking I can solve my problem by supporting KSPROPERTY_AUDIO_VOLUMELEVEL?
--
Tim Roberts, timr@xxxxxxxxx<mailto:timr@xxxxxxxxx>
Providenza & Boekelheide, Inc.
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