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From: Tim Roberts on 18 Apr 2010 02:29
MsdnSubscriber <MsdnSubscriber(a)discussions.microsoft.com> wrote:
>
>Ok...now I'm a bit confused because sAPOs and xAPOs are two different
>things..right? To me XAPOs are the same as DirectShow filters...which means
>that if I write an XPO then the effect will apply only to the local stream or
>XAudio based applications.

Yes.

>However, sAPOs apply to the entire system...which is one my requirements
>i.e. to apply effect on the combined audio stream of the system that is ready
>to be sent to an audio endpoint.

Yes. However, Microsoft's philosophy is that APOs are an extension of the
hardware. They are installed with the audio driver. If you are creating
the audio hardware, then it may be the right solution for you.
--
Tim Roberts, timr(a)probo.com
Providenza & Boekelheide, Inc.
From: MsdnSubscriber on 18 Apr 2010 06:17
So basically I need to write an sAPO.

Is it possible to install an sAPO without a hardware/audio driver? there are
instructions in DDK on how to install just the APO...but they don't mention
anything about installing the audio driver.

Also, is there a limit of one GFX sAPO per system? or can there be
multiple-different GFX sAPOs linked in chain?

Thanks!

"Tim Roberts" wrote:

> MsdnSubscriber <MsdnSubscriber(a)discussions.microsoft.com> wrote:
> >
> >Ok...now I'm a bit confused because sAPOs and xAPOs are two different
> >things..right? To me XAPOs are the same as DirectShow filters...which means
> >that if I write an XPO then the effect will apply only to the local stream or
> >XAudio based applications.
>
> Yes.
>
> >However, sAPOs apply to the entire system...which is one my requirements
> >i.e. to apply effect on the combined audio stream of the system that is ready
> >to be sent to an audio endpoint.
>
> Yes. However, Microsoft's philosophy is that APOs are an extension of the
> hardware. They are installed with the audio driver. If you are creating
> the audio hardware, then it may be the right solution for you.
> --
> Tim Roberts, timr(a)probo.com
> Providenza & Boekelheide, Inc.
> .
>
From: Tim Roberts on 20 Apr 2010 02:08
MsdnSubscriber <MsdnSubscriber(a)discussions.microsoft.com> wrote:
>
>Is it possible to install an sAPO without a hardware/audio driver? there are
>instructions in DDK on how to install just the APO...but they don't mention
>anything about installing the audio driver.

Well, there has to be SOME audio device. The the APO is installed in the
audio path -- if there's no hardware, there's no path.

>Also, is there a limit of one GFX sAPO per system? or can there be
>multiple-different GFX sAPOs linked in chain?

There is only one GFX APO. When you install an APO, you're supposed to go
check to see if there was one already and chain to it yourself. There's a
white paper that describes this.

http://www.microsoft.com/whdc/device/audio/vista_sysfx.mspx
--
Tim Roberts, timr(a)probo.com
Providenza & Boekelheide, Inc.
From: MsdnSubscriber on 21 Apr 2010 00:04
"Tim Roberts" wrote:

> Well, there has to be SOME audio device. The the APO is installed in the
> audio path -- if there's no hardware, there's no path.

An audio-out device is present in almost all PCs these days. What I was
asking was if it is possible for a third-party/developer to install GFX APO
for an audio-device already installed on the system - supplied by someother
manufacturer. Or does the APO need to be installed with the audio device's
driver?

> There is only one GFX APO. When you install an APO, you're supposed to go
> check to see if there was one already and chain to it yourself. There's a
> white paper that describes this.

That's what I wanted to confirm...there's supposed to one GFX APO...but then
you said that if there is already one then I'm supposed to chain mine to
it...which implies that there could be multiple GFX APOs linked together and
active at the same time?


> http://www.microsoft.com/whdc/device/audio/vista_sysfx.mspx

Yes, I've seen this...however, I'm still confused about the above questions
thats why I'm asking here :)

Btw...thanks for all the help so far!
From: Tim Roberts on 21 Apr 2010 23:44
MsdnSubscriber <MsdnSubscriber(a)discussions.microsoft.com> wrote:
>
>An audio-out device is present in almost all PCs these days. What I was
>asking was if it is possible for a third-party/developer to install GFX APO
>for an audio-device already installed on the system - supplied by someother
>manufacturer.

Possible? Yes. Supported? No. It requires a certain amount of trickery
and subterfuge, and goes against Microsoft's philosophy, which is that the
APO is part of the hardware.

>Or does the APO need to be installed with the audio device's driver?

That is Microsoft's view. That is not architecturally enforced, but some
things make assumptions that it will be the case.

>That's what I wanted to confirm...there's supposed to one GFX APO...but then
>you said that if there is already one then I'm supposed to chain mine to
>it...which implies that there could be multiple GFX APOs linked together and
>active at the same time?

If you think about it for a moment, if an APO comes only from the hardware
manufacturer, then there are only two possible APOs: the one from the
manufacturer, and the standard Microsoft effects APO. Unless trickery is
involved, there can't be more. If trickery is involved, then anything can
happen.
--
Tim Roberts, timr(a)probo.com
Providenza & Boekelheide, Inc.
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