I don't think it would work with video signal, but if something like this exists for video signal, then it could work!

...and now, something completely different... a lot of time ago, I was reading in a thread that a user have captured the RGB signal from a laserdisc (with RGB output, of course) three times, each for read, green and blue signal, then recombined it (don't rembember if with avisynth) and the result was better than "straight" composite.

Now, it happens I have a laserdisc player with RGB output - but I was not able to find anywhere a DB9-to-RCA (or to BNC) cable... if someone could provide me that cable, or point me to some store that has it, I will be more than happy to test this technique!