[wdmaudiodev] Re: MSVAD multistr multiple streams supported or NOT !!!!
- From: Tim Roberts <timr@xxxxxxxxx>
- To: wdmaudiodev@xxxxxxxxxxxxx
- Date: Thu, 12 Mar 2009 09:54:52 -0700
Vipin Kumar wrote:
>
> i am developing a driver off MSVAD multistr but when i tested
> the sample driver on XP SP3, multiple streams are not getting created..
>
> i am playing 3 different songs using 3 different, so as 3 streams
> should be simultaneously active however, only 1 stream is created,
> ...
> CMiniportWaveCyclic::NewStream ( minwave.cpp ) is callled only when
> no stream is active. If only 1 stream can be active then what is the
> difference of MSVAD simple and MSVAD multistr .
>
> Can somebody throw some light as to why the sample is not working.If i
> am thing right 3 media player, playing 3 songs(simulateneously in 3
> different players) should make 3 active streams. is this true???
Nope, only in user mode. Windows includes a "kernel mixer", which will
mathematically mix all of your streams into a single data stream to feed
to the default playback device. Remember, you haven't really created
multiple "streams". As far as the system knows, what you have created
is multiple separate output DEVICES.
If you want multiple output streams to go to separate output devices,
you have to change each application to request that output device.
Barring that, all applications will output to the default playback
device, and all streams will be mixed in the kernel mixer.
However, I'm wondering why you would WANT separate apps to go to
separate output devices.
--
Tim Roberts, timr@xxxxxxxxx
Providenza & Boekelheide, Inc.
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