Ivan R. Judson judson at mcs.anl.gov
Sat May 25 10:11:02 CDT 2002

Hi Abraham,

It's great news that you are working on installing an Access Grid Node!
Anything we can do to help we'll try to do.

I'm not familiar with VCON or the Accord MCU, but I'll do the best that
I can.

On question #1: VFW vs WDM, this is what I've learned:

Vic is using the older vfw api because it's older code, primarily
supported on non-microsoft operating systems.  Converting it to use the
more modern WDM, or more current DirectShow interfaces to Video Capture
would be ideal, but we haven't gotten to it.  From what I do know, the
vfw API is a legacy interface on most current capture hardware, so as
such it might have lower performance, but I'd be surprised if it was a
full 10 FPS! 

Jay Beavers from MS Research might have some better suggestions.

On question #2: Which capture card to use:

We recommend the Hauppage card because we're familiar with it.  We've
also used the Osprey card (at least one model anyhow).  If you are
familiar with other capture cards and can debug the interaction with
Vic, I'd say go for it.  But, you'll get less help from the current
community than you would if you use what's more familiar.  It's a
trade-off, but the choice is yours.



-----Original Message-----
From: owner-ag-tech at mcs.anl.gov [mailto:owner-ag-tech at mcs.anl.gov] On
Behalf Of AGAY at vms.HUJI.AC.IL
Sent: Saturday, May 25, 2002 5:51 AM
To: ag-tech at accessgrid.org
Subject: [AG-TECH] VfW and WDM

                                                  ag-tech at accessgrid.org


 We are trying to build a kind of mini Access Grid node  (actually there
will be 4 of them, one in each campus).

 We would also like to use the mini node as a conference
 room for VRVS (we have a reflector), and with the VCON
 H.323 clients and Accord MCU already bought by our IUCC.

 Some dumb questions:

 1.  Both VRVS/VIC and AG/VIC use on Windows the VfW
     (Video for Windows) driver interface.

     If the video capture card driver is WDM, then the
     Microsft VfW-to-WDM Mapper automatically kicks in
     and provides compatibility?  Is it possible the
     Mapper will lower frame rate by a factor of 10?
     Should we use only VfW drivers?

 2.  Should we stick with Hauppauge or Osprey capture
     cards, or others like LifeView/FlyVideo are ok?

 Abraham Agay

 Abraham Agay (Hebrew U. of Jerusalem)
 Email:  agay at vms.huji.ac.il

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