[wdmaudiodev] please remove me from the maillist
- From: Patrick Zou <patrick_zou@xxxxxxxxxxx>
- To: <wdmaudiodev@xxxxxxxxxxxxx>
- Date: Mon, 13 Nov 2006 14:49:26 +0000
From: jeff@xxxxxxxxxxxxxxxxxx: wdmaudiodev@xxxxxxxxxxxxxxxxxxxx: [wdmaudiodev]
Vista audio engine sampling rate woesDate: Mon, 13 Nov 2006 15:05:42 +1100
One of our products is an AES3 (aka AES/EBU) 24-bit sound card, on which the
user can set the hardware sampling rate as 96kHz, 48kHz, 44.1kHz or have it
derived from external AES11 sync reference. While I can do sampling rate
conversions in the DSP on the card, I was thinking that since Vista runs its
audio engine at a fixed rate independent of applications, it would be nice if I
could set that rate to be the same as the card's hardware rate so as to avoid
an additional sampling rate conversion.
The WDK's discussion of Data-Intersection Handlers speaks of situations such as
this and recommends creating pin data range entries for all the possible
sampling rates and then using either the data range intersection handler or the
format testing in NewStream to reject rates that don't match the hardware rate,
but this doesn't seem to work under Vista RC2 - it insists on using 16-bit
44.1kHz (or whatever other OEM format I specify in the INF file) and then
refuses to work if that doesn't match the hardware rate, without even trying
any of the other supported rates.
If I create just one entry in the pin data range table and make its sampling
rate equal to the hardware rate, I can almost achieve what I want, except if
the user changes the hardware rate, Vista's audio engine insists on still
trying to use the original rate, even after a reboot. The only way to then make
it work again is to manually go into the Advanced page of all the render and
capture endpoint settings and change them to the new rate.
Is there a way to achieve what I want under Vista (ie. to dynamically change
the audio engine's sampling rate to match the current hardware rate of my
card), or do I have to set the OEM format in the INF file to 24-bit 96kHz and
rely on the sampling rate converter in my DSP to convert that to the hardware
rate?
Jeff Pages
Innes Corporation Pty Ltd
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