[wdmaudiodev] Re: AVStream Audio Frustration
- From: Matthew van Eerde <Matthew.van.Eerde@xxxxxxxxxxxxx>
- To: "wdmaudiodev@xxxxxxxxxxxxx" <wdmaudiodev@xxxxxxxxxxxxx>
- Date: Fri, 2 Nov 2012 23:03:29 +0000
I understand capture devices can show up twice in DirectShow. For example, if
I have a microphone KS filter and muxed line-in/microphone KS filter, I get
five DirectShow filters:
http://blogs.msdn.com/b/matthew_van_eerde/archive/2010/12/18/10014843.aspx
-- Audio Capture Sources ({33D9A762-90C8-11D0-BD43-00A0C911CE86}) --
Front Microphone (High Definiti
Line In (High Definition Audio
Rear Microphone (High Definitio
...
-- WDM Streaming Capture Devices ({65E8773D-8F56-11D0-A3B9-00A0C9223196}) --
HD Audio Microphone
HD Audio Muxed capture
That said, I believe it's normal and expected behavior for DirectShow to
sometimes insert software format conversion and to sometimes not. (I don't
consider myself a DirectShow guru; perhaps this question should go to
http://social.msdn.microsoft.com/Forums/en/windowsdirectshowdevelopment/threads
)
Can you clarify why it is a problem for a format converter to be inserted above
you?
From: wdmaudiodev-bounce@xxxxxxxxxxxxx
[mailto:wdmaudiodev-bounce@xxxxxxxxxxxxx] On Behalf Of Matt Gonzalez
Sent: Friday, November 2, 2012 3:59 PM
To: wdmaudiodev@xxxxxxxxxxxxx
Subject: [wdmaudiodev] Re: AVStream Audio Frustration
Hello Tim,
I share your frustration; since Windows Vista, the new architecture caches the
audio format in the registry and frequently ignores the capabilities reported
by the driver.
Have you tried KSEVENT_PINCAPS_FORMATCHANGE? It's only supported on Windows 7,
but that may be what you're looking for.
Cheers,
Matt
On 11/2/2012 3:54 PM, Tim Roberts wrote:
What I'm saying is that I am pretty well convinced this is not a problem in my
filter. I'm doing the right thing, in AVStream terms. In the sysaudio/waveIn
case, someone above me is deciding what my default audio format is, and caching
that information without consulting me, and without considering that my
capabilities might change over time. That's what I need to nail down.
--
Tim Roberts, timr@xxxxxxxxx<mailto:timr@xxxxxxxxx>
Providenza & Boekelheide, Inc.
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