[AG-TECH] Realtek compatibility with RAT

Douglas Kosovic douglask at itee.uq.edu.au
Tue Sep 11 22:36:25 CDT 2007


Hi Sam,

> I understand that Realtek audio cards (chips?) are not compatible with
> RAT. Is this still the case for the latest RAT, bundled with AG 3.1
> Beta? (I no longer have a Realtek card to test.)

It is only the Intel HD audio with the RealTek codec. Earlier RealTek based
AC'97 audio is fine.

> If so, for what reasons? I assume they are technical; what are they?
> Is the problem at RAT's or Realtek's end? Is there a feasible work-around?
> Is there potential to actually solve the problem? I've heard something
> about the Realtek chips not supporting 'proper' multi-cast...

I've got a MacPro with Realtek HD onboard audio, RAT works fine on it with
MacOS X and Linux, but not WinXP and Vista.

RAT doesn't support separate input and output audio devices. Unfortunately
with the RealTek HD driver on WinXP, the driver appears as separate input
and output audio devices, so doesn't get listed as an audio device within
RAT.

With Vista, all audio drivers appear as separate input and output devices,
so RAT doesn't work with any audio device on Vista.

> I ask because I am employed by VPAC (www.vpac.org) and work with both
> RAT and VIC. My boss is interested in providing realtek compatibility.

It requires modifying the RAT code to support separate input and output
devices. I've been thinking about modifying the code, but haven't gotten
around to it. You can grab the RAT code from the Sumover SVN repository,
see:
   http://mediatools.cs.ucl.ac.uk/nets/mmedia/wiki/SvnDev

As you don't have RealTek HD audio, to reproduce the issue, just use two
separate audio devices, e.g USB headset for input and onboard audio for
output.

> I'm not sure of the contractual and intellectual property licensing
> specifics - we're a not-for-profit organisation for what it's worth -
> but it'd be good to get an idea of the amount of work required, if it
> is at all feasible, to provide realtek compatibility.

The code modifications will involve an understanding the Win32 MME (audio)
API. The file that will require the most modifications is auddev_win32.c,
see:
 
http://mediatools.cs.ucl.ac.uk/nets/mmedia/browser/rat/trunk/auddev_win32.c
There is also a bit Tcl/Tk code modification to the GUI, but that isn't
significant.


Cheers,
Doug






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