I have a very narrow “is this supported” question for NT6+ regarding user
mode driver / waveform audio.
I realize that Vista/LH completely revamped the audio system and that as
documented ‘mixer’ devices exposed via legacy (NT4) style audio drivers are
no longer supported.
What I cannot seem to answer is for devices that expose PCM audio stream
access via a user mode driver / kernel driver pair - is this model still
supported?
An important point here is that these ‘devices’ never had nor will have
‘mixer’ functionality (or auxiliary audio or MCI) but are just PCM streams.
Indeed, they are telephony channels and are exposed (made known to)
applications via a corresponding TAPI 2.x TSP which allows querying the
wave/in/out device ID as the means of identifying the PCM device.
As best I can tell the analogous “voice modem” support for UNIMODEM
continues to be delivered using exactly the same technique and it sure seems
to be present in Win7.
The key question is not if it works (I know the answer to that and it is
‘yes’) but “is it supported?”.
If the answer is “no, it is not supported to add your own wave(n)=blah.drv
in DRIVERS32 anymore and expect MMSYSTEM to load it for waveform audio” then
what is the alternative driver to usermode transition mechanism to move PCM
audio in this specialized case? All applications interacting with this
device start with TAPI 2.x, call lineGetID() with wave{/in|/out|/in/out} to
get a wave device and then use waveform audio APIs from MMSYSTEM.
Thanks,
Dave Cattley
Consulting Engineer
Systems Software Development