[wdmaudiodev] custom multichannel devices in Vista
- From: "Marc Titinger" <mtittinge@xxxxxxxxxxx>
- To: wdmaudiodev@xxxxxxxxxxxxx
- Date: Fri, 21 Jul 2006 18:46:37 +0200
Hi All,
We developed a wavepci miniport for a multichannel sound card. In WinXP, we
could expose a Directsound device with 24 channels for instance, and have
Media Player 10 play a wave file with 24 interlaced channels without
problem. This worked in our case, because DirectSound called into the
miniport?s DataRangeIntersection handler and retrieved in return the min
between the actual device channels (24) and the channel count it requested
(65536).
In Vista, this preliminary call into the DataRangeIntersection handler seems
to be gone (with kmixer?) . Instead, it looks like the channel layout
defined with mmsys.cpl is used, but the choice can be ?only? mono to 7.1.
I added a GET and SET support for KSPROPERTY_AUDIO_CHANNEL_CONFIG so that
the KSAUDIO_SPEAKER_DIRECTOUT (zero) value can used with
IDirectSound::SetSpeakerConfig, but a successful call to this method (and
Format.nChannels = 24 ) still doesn?t prevent the stream to be created
with the profile defined in mmsys.cpl.
Should?nt DirectSound keep asking for a datarange intersection when the
application says ?this is a custom channel mapping? by setting
IDirectSound::SetSpeakerConfig(0) ? Am I doing something wrong (besides
using lots of channels ^^) ?
Thanks for your help,
Marc.
http://www.osronline.com/DDKx/stream/pcdesign_29bb.htm
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