kind of an odd question but what was the first Macintosh to offer A/V in jacks as standard? also were there any A/V in Nubus or PDS cards for older Macintosh II systems?
If we're talking about video capture the Quicktime software infrastructure and compatible hardware dates back to the late Mac II era the SuperMac Video Spigot was a notable milestone, circa 1991, but so far as I'm aware the first Macs with video capture capabilities built in were the mid-1993-vintage Quadra 660/840AV machines.
Strictly speaking there were versions of the "ComputerEyes" and similar frame-grabbing video digitizers made to be plugged into the original Macintosh pretty much from day one, but I don't imagine that really counts.