To me, and in the usage I am familiar with, vids would not be multimedia--because that is the media they are--video, meaning only one media--pictures, sound, music, etc.--no matter where they come from--all combine to form that media.

So I disagree with the notion that the multi-media indicates the source (maybe you have a vid featuring television, music, and magazine stories, for instance)--it all comes together to make one media.

Multimedia would mean using the video as part of my theater presentation and such.