[wdmaudiodev] Re: AW: Re: SFX APO not opened for each playing app
- From: Tim Roberts <timr@xxxxxxxxx>
- To: wdmaudiodev@xxxxxxxxxxxxx
- Date: Fri, 13 Apr 2018 13:18:22 -0700
Johannes Freyberger wrote:
* Like what kind of parameters?
I.e. different EQ-Settings if my SFX is an EQ, or different gain
adjustments for an AGC – I think there’s a lot of use cases.
I don't think there are. How could you possibly administer that? What
would the user experience be? How would you control it?
The application is supposed to be in charge of all of this. That's
essentially why the APO model is so restrictive. If an application
wants individual EQ or gain adjustments, then the application will make
that happen. It's not up to the hardware to do that on the
application's behalf. Remember -- an APO is considered by Microsoft to
be part of the hardware. You can't install an APO by itself -- only as
part of the INF file for a device.
I really would like to process the audio streams from different
applications in a separate way, before they are mixed down by audiodg
and finally arrive in my driver as an already mixed bunch of samples.
This just seems like a Bad Idea. One of the major reasons Microsoft
redesigned the audio subsystem in Vista was because too many people were
trying to "add value" by writing helpful audio filter drivers. It got
to the point that professional audio device manufacturers simply could
not get reliable and reproducible results, because they couldn't predict
what filters were interfering. As of Vista, the application is in
charge. The philosophy is that no one should be inserting filters or
effects that the application (or the user) didn't specifically request.
Tim Roberts, timr@xxxxxxxxx
Providenza & Boekelheide, Inc.
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