in the past i have used an interface device made by "Dazzle".
input -
TV composite video (what is the correct term ?)(look like stereo cables)
output - Firewire
in that case i used an Adaptec Firewire card. & spent many hours compressing
my VHS version of the "Matrix" in various forms. circa 2003.
a lot of video cards have a "video in video out" connector. they come with
a mating cable - which i think also has composite video connectors. i've
never installed that.
what do you want to do with it once you get the videos into the computer ?
sort of like have a "jukebox" that has a bunch of movies and music ...
anyway, hope that helped. i know there's more modern stuff.