As I said earlier in the thread:
Could be a refresh rate difference between what the video driver wants to sync to and what the Bink Player that's being used in-game wants to do....I'm kinda encountering the same problem myself: Back when I was using some older 3Dfx drivers, other bink movies would run fine in-game (this is in games other than FF8pc), but ever since I had updated to one of the newer driver sets, I get stuttering in ANY bink movie....and it annoys the crud out of me.
Anyway, the point is that it is possible for the actual video card driver itself to be causing this problem, and yes, I know that that suggestion is gonna get a big "Duh", but I might as well get it out there anyway, LOL.
Another thing this may be related to is your sound card, especially if you're using a hardware buffer for acceleration (which is usually a good thing, its essentially the sound card equivalent of hardware TnL, in terms of offloading the CPU).....anyway, despite the fact that FF8pc's problem on my machine with running the hi-res movies could be related to that video driver incompatibility, I found that turning my card's hardware buffer off somehow fixed it, but it comes at the cost of the fact that that also means EAX support is disabled, as it relies on the hardware buffer to function.