ok so here's my situation: I filmed and edited a project in full HD. (1920 x 1080). I need to export a 640 x 480 .mov version to be put on the web (without squashing it). I know I'm prob going about it the wrong way, but here's what I did... I exported (from main hd sequence) as a full sized qt file and then started a new project in fcp. I then imported the 16x9 hd video into a 4x3 ntsc sequence & brought the aspect ratio down until it fit. I then exported that as a .mov. Everything looks good except that there's scan lines (is that what you call them?) when it's played back on quicktime.
I know there's an easier way of doing this, can someone please steer me in the right direction? and how did I get the scan lines & how do I get rid of it in the process?