[wdmaudiodev] Re: Audio AGC?
- From: Matthew van Eerde <Matthew.van.Eerde@xxxxxxxxxxxxx>
- To: "wdmaudiodev@xxxxxxxxxxxxx" <wdmaudiodev@xxxxxxxxxxxxx>
- Date: Wed, 19 Dec 2012 22:40:23 +0000
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
From: wdmaudiodev-bounce@xxxxxxxxxxxxx
[mailto:wdmaudiodev-bounce@xxxxxxxxxxxxx] On Behalf Of Tim Roberts
Sent: Wednesday, December 19, 2012 2:35 PM
To: wdmaudiodev@xxxxxxxxxxxxx
Subject: [wdmaudiodev] Audio AGC?
I have an AVStream virtual audio driver, based originally on the "avsamp"
sample but almost completely rewritten. I serve exactly one format at a time,
usually 22050-M-16. The only properties I support are the two jack
descriptors. If I connect directly to the device in graphedt under the "WDM
Streaming Capture Devices" category, audio plays fine. But if I build a graph
using the instance under "Audio Capture Sources", it appears that the system
audio engine gets involved. One minor side effect is that the pin always says
44100-S-16, even though I don't support that format. The audio does play,
however (so someone is converting).
The larger problem, however, is that my audio is being boosted to the point of
distortion. I don't understand where this is coming from. I'm currently
attenuating my own signal by 50%, and the resulting stream is still painfully
overdriven.
Where is this coming from? Is there some AGC in the audio system? Does it
sample a short period to decide what my average volume is and boost to
compensate? How can I stop this?
--
Tim Roberts, timr@xxxxxxxxx<mailto:timr@xxxxxxxxx>
Providenza & Boekelheide, Inc.
Other related posts:
