Need Help: Distorted "Pixelated" Footage in AE

[Kwan Khan]

I'm working on AE CS4, and this just recently started happening. When I Import quicktimes footage, the image becomes all blocky and jagged, like it's being pixelated. I've tried reinterpreting the footage, making sure I'm viewing it in Full quality, etc, but no luck. My comp window is set to full res. I have other graphics made in AE that look fine within the same comp.

Anyone have any ideas?