As I reread your question, it makes me wonder if I introduced the problem when i imported through MPEG Streamclip. Perhaps i made it 640X480. If I reendcoded it would I be able to make that the reference file — or would I have to recut the whole thing?
I am helping a friend cut a shorter reel from a very long DVD collection of scenes he has. On the DVD I pulled from, none of the clips looked squeezed. When I finished cutting and burned a DVD I realized that much of what I cut looked squeezed. I noticed in the browser it tells me it’s 640X480. And I had my timeline set to 720. When I switched a clip to 640 in a new sequence it unsqueezed. That’s why I am barking up this tree.
Danny