jerky video

[AntiHero]

I'm using Adobe Premiere CS3 to produce my video, and when I export it to avi the resulting video has many sections which are slightly jerky/jittery. It's almost subliminal, but it's nearly constant and impossible not to notice. It's like working under a light that's just barely flickering - it bothers the eyes even if the light doesn't go completely out. The thing is, I can't find a common denominator. It begins at a clip where I'd adjusted the speed, but it also affects clips where the speed is not adjusted. Does anyone have a similar experience or idea as to the cause/solution?

Thanks.

[Pwolf]

post an example?

[BasharOfTheAges]

Might also be worth mentioning how the video is encoded.

[AntiHero]

The problem has improved a bit. I cropped a segment out that's jittery every time, but on its own there's no jitter. My theory is that it has something to do with the machine I'm working on (not my own). Adobe gets really low on memory while I'm working.