Got the SGI-propriatary VW320-specific drivers? Been a while, but the last time I looked there were some VW320 downloads available on SGI's Supportfolio site.
If you haven't already been there, SGI also has some VW320 info archived on their ftp.
There still is some info out there regarding video capture:
and a clue as to which SGI-specific digital media modules (sgidmedia.dll, sgidv.dll, sgijpeg.dll, sgilivfw.dll, sgiqt.qtr, sgiqt.qtx, sgival.dll, sgiyuv.dll) and drivers (sgijack.sys, sgilivid.sys) were used by the VW320:
Some of the VW320 drivers look to still be available on what's left of reality.sgi:
And there's also a few "win2k" ssk patches on SGI's public ftp:
Looks like a number of the links are MIA, but there is a quicktime capture utility over in the programming examples folder:
There's also a few additional mentions of the VW here: