The board you're holding, as does the box with the credit card remote, and PCB copyright looks like what was released with the Quadra 630 system. So it has the narrow
34pin DVA Connector anyway? That card will work with anything from Q630-6500 without problem, but you need the wider
60pin DAV connector for use with the PCI based AVID kit linked above if that was your wont. VidCard and USB cards you've chosen are better suited to that machine I think.
Apple MPEG Media System is for use in the 040 based 6xx series' PDS Slot. It has the narrow DVA cable setup. It was for MPEG1 playback and PhotoCD as I recall. Played with it last about 10 years ago?
The Apple MPEG Media System was produced by Apple Computer to provide some 68040-based Macintosh models with the ability to play back MPEG-1 video in real time before the introduction of PowerPC processors. The Apple MPEG Media System card fits the PDS slot of the Quadra 630 series (as well as...
apple.fandom.com
edit: looks like an adapter cable kit was available to use the older DVA boards like yours with the DAV/AVID Cinema Card in your 6500.