[wdmaudiodev] Re: Enumeration of Nodes on Instantiated Pins
- From: "Mitchell Rundle" <mitchr@xxxxxxxxxxxxx>
- To: <wdmaudiodev@xxxxxxxxxxxxx>
- Date: Wed, 25 Sep 2002 11:50:13 -0700
I'm not laughing :) we do similar stuff in our test apps. If you only
have 1 renderer, then you can simply use the wave out DST line (master
volume) and set the waveout SRC line (assuming there is one) to unity.
If you have multiple devices, then the difficulty is in correlating
wave, mixer and dsound devices. Aside from that problem, I don't see
any reason to use KS at all.
Sorry for the tardiness of the whitepaper. I will be working on it this
week.
Mitch
-----Original Message-----
From: Art Edwards [mailto:snowdog0@xxxxxxxxxxxx]=20
Sent: Wednesday, September 25, 2002 11:28 AM
To: wdmaudiodev@xxxxxxxxxxxxx
Subject: [wdmaudiodev] Re: Enumeration of Nodes on Instantiated Pins
You assume correctly. I am referring to the mixer API.
OK. But don't laugh.
I'm interested in implementing an el-cheapo audio generator/analyzer.
I've=20
been using Directsound for the generator. I'd like to have some ability
to=20
predict what the output level (in volts or something similar) will be.
For calibrating the system, I was hoping to take the approach of
adjusting=20
the wave volume while reading the volume node until I get it somewhere
near=20
0dB. Then I figured I'd capture the mixer API setting & use that. I
told=20
you it was el-cheapo.
I suppose a better approach would be to go Kernel Streaming the whole=20
way. Then, I'd have a handle to the pin I created. But, I'm not sure
how=20
to accomplish that. Any news on that white-paper BTW ?...
At 01:48 PM 9/25/2002 , you wrote:
>By mixer, I assume you mean the mixer API and not Kmixer (Kmixer=20
>doesn't need to know anything about the topology of downstream=20
>filters).
>
>The mixer API gets the topology of the whole graph through Sysaudio.=20
>Sysaudio exposes the audio graph as a few unconnected "virtual"=20
>filters. E.g. The "wave" render graph is virtualized as a single filter
>with all the nodes of all the real filters in the graph. The=20
>inter-filter pin-to-pin connections are hidden in this view, which=20
>simplifies things for the clients (e.g. Windows APIs). So if the mixer
>API needs to set a volume control, it does so through a "virtualized"=20
>pin handle on the Sysaudio filter. Sysaudio routes the call=20
>appropriately.
>
>Out of curiosity, what are you trying to accomplish (big-picture-wise)?
>Thanks.
>
>Mitch Rundle
>Microsoft Corporation
>
>This posting confers no rights and contains no guarantees.
>
>
>-----Original Message-----
>From: Art Edwards [mailto:snowdog0@xxxxxxxxxxxx]=3D20
>Sent: Wednesday, September 25, 2002 10:00 AM
>To: wdmaudiodev@xxxxxxxxxxxxx
>Subject: [wdmaudiodev] Re: Enumeration of Nodes on Instantiated Pins
>
>
>
>Yes, I forgot to mention that I can get the count of pin instances from
>the filter.
>
>Hmmm, as I suspected...
>
>So, how does the mixer send property requests to the volume =
control=3D20=20
>pin-nodes on a wave out filter ?
>
>At 12:43 PM 9/25/2002 , you wrote:
>
> >It depends on what you mean by "enumerate". You can infer the count=20
> >of
>
> >pin instances, but you cannot get handles to them (which is what=20
> >you=3D20 need for sending property IOCTLs) unless you instantiated =
them
> >yourself
>
> >(e.g. via KsCreatePin).
> >
> >Mitch Rundle
> >Microsoft Corporation
> >
> >This posting confers no rights and contains no guarantees.
> >
> >-----Original Message-----
> >From: Art Edwards [mailto:snowdog0@xxxxxxxxxxxx]=3D3D20
> >Sent: Wednesday, September 25, 2002 5:45 AM
> >To: wdmaudiodev@xxxxxxxxxxxxx
> >Subject: [wdmaudiodev] Enumeration of Nodes on Instantiated Pins
> >
> >
> >
> >Does anyone know if an application can
> >enumerate pin instances on a filter ?
> >
> >If so, did I miss it when I searched the
> >DDK help and the WDMAudioDev archives ?
> >Or, is it top-secret ?
> >
> >I am trying to send IOCTL_KS_PROPERTY
> >requests to volume nodes associated with
> >a pin instance (i.e. so called
> >pin-nodes) on a filter. I have been
> >successful sending such requests to
> >nodes that are global to the filter.
> >(i.e. so called filter-nodes).
Art Edwards
Art's <http://members.localnet.com/~snowdog0/Resume>resume.
Art's <http://www.soniqboom.net>band (a.k.a. Soniq Boom).
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