[wdmaudiodev] Re: Issues in installing custom sAPO.
- From: Frank Yerrace <Frank.Yerrace@xxxxxxxxxxxxx>
- To: "wdmaudiodev@xxxxxxxxxxxxx" <wdmaudiodev@xxxxxxxxxxxxx>
- Date: Thu, 11 Oct 2012 20:02:32 +0000
Tim's statements are largely correct. There are two "entities" that control
what signal processing is available to a user: the application and the audio
driver. Windows has no model for a third player to be involved. Even just
having these two controlling entities has caused problems in some (important)
user scenarios.
Frank Yerrace
Microsoft Corporation
-----Original Message-----
From: wdmaudiodev-bounce@xxxxxxxxxxxxx
[mailto:wdmaudiodev-bounce@xxxxxxxxxxxxx] On Behalf Of Robert Bielik
Sent: Thursday, October 11, 2012 11:06 AM
To: wdmaudiodev@xxxxxxxxxxxxx
Subject: [wdmaudiodev] Re: Issues in installing custom sAPO.
Tim Roberts skrev 2012-10-11 19:07:
> There is no clear and obvious path to implement general-purpose audio effects
> products in Vista and beyond. That was mostly an intentional design decision.
> There were so many poorly written effects in the pre-Vista world that it was
> impossible to implement reliable professional audio applications.
Really ? Do you have any documentation to back up this statement ? Question is
not only for Tim but any Microsoft member of this list.
In the pre-Vista world there was only WaveCyclic and the impossibility for
reliable professional applications lay in the core of the WDM audio
implementation and more importantly, OS thread scheduling. On XP I cannot get
any reliable low latency app to work without setting process+thread to RT. Not
good, and possibly VERY unstable. With Vista++, WaveRT and reliable scheduling
with MMCSS has had that changed significantly, but that has *nothing* to do
with APOs or not.
And secondly, since the audio server functionality now is User Mode (and thus
the execution of any APO effects), as opposed to Kernel Mode in pre-Vista,
there is even lesser of a chance to mess things up! I think it is only a
"convenient" route taken by Microsoft.
/Rob
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