[wdmaudiodev] Re: AVStream Audio Frustration
- From: Tim Roberts <timr@xxxxxxxxx>
- To: "wdmaudiodev@xxxxxxxxxxxxx" <wdmaudiodev@xxxxxxxxxxxxx>
- Date: Fri, 2 Nov 2012 16:46:21 -0700
Matthew van Eerde wrote:
>
>
> Can you clarify why it is a problem for a format converter to be
> inserted above you?
>
I may have thrown up too much information and distracted us from the
main point, or maybe it's just that I'm isolating the problem better as
time goes on. I don't really care about DirectShow; my use case is
waveIn. It just so happens that Graphedt shows the same behavior in
that one case.
Someone, somewhere, is caching my "default audio format". I think we
can all agree that's true; it's displayed in the control panel
Microphone Properties "Advanced" tab. When I change that selection (as
I've just learned), the Audio Engine does go through my intersect
handler. It will only allow a selection that passes my intersection.
The issue is that, in the sysaudio/waveIn scenario, the system will only
send me the "default audio format", even if that format no longer passes
my intersection. If my format set has changed, I fail in the SetFormat
handler and unhappiness ensues.
Say that I select 22-M-16 in control panel. Now, let's say that I
reboot, and after the reboot I can only handle 44-S-8. In that case,
the system will still only connect at 22-M-16 (from the cache), even
though that no longer passes my intersect handler.
Matt Gonzalez wrote:
> Have you tried KSEVENT_PINCAPS_FORMATCHANGE? It's only supported on
> Windows 7, but that may be what you're looking for.
I'm not sure I know how to send that. That would be a pin event
(wouldn't it?), and I can't connect the pin if the format doesn't
match. I suppose I could accept the bad format then generate the
event. Hmmm.
--
Tim Roberts, timr@xxxxxxxxx
Providenza & Boekelheide, Inc.
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