anti-alising problem?
 

I have made a few DVD releases but one thing puzzles me: in the final DVD version the picture looks like lack of anti-aliasing. If there is a diagonal line it looks jagged. I thought it was just because of the nature of interlacing video. But why normal interlaced TV programs don't have this artifacts?
Would that problem be gone if I shoot 30f? I always have been shooting 60i so far.