It's been a while since I dabbled in it, but I believe you need a video capture card or device. Which usually puts it in a rather bloated mp4 format. Then you need to scale it down to manageable size by transcoding into another format like xvid.
There used to be plenty of free software for converting video, I used the Doom9.org site way back when(which appears to be down). I remember stripping all the episodes of Kung Fu from DVDs and put it into manageable sizes xvid format, for archiving. Took weeks to transcode all the episodes - a very CPU intensive task.