GameCube FMV - why so poor looking?

Why is it that the FMV sequences in Resident Evil and Resident Evil Zero look so blatantly compressed, and overly compressed?
Watching any of the FMV sequences shows what looks like a rather dodgily compressed DivX video - and yet both games come on 2 discs so surely space isn't really the problem?
Just out of curiosity I watched the original Playstation version of Resident Evil, and I have to say the quality of the video was superior, which is surprising.

Any particular reason the FMV ain't so hot on the RE's? (I can't really speak for other GC games as the only other GC game I've ever played is the appalling True Crime and I don't recall it having any FMV - just cutscenes.)