I just found that when taking one of these clips into QuickTime Player, I can open “Properties/MPEG2 Video/Visual Settings”, then uncheck “Preserve Aspect Ratio” and manually change the Current Size from 720×404 to 720×480. When I do this, the frame rate changes from 30 fps to 24 fps.(?) I have no clue why a change in image size and pixel aspect would affect frame rate – maybe this is related to the MPEG-2 spec. I think my problem is solved for now, but if anyone has more insight into working with MPEG-2 files with 24 fps source footage, I’d appreciate any shared knowledge or experience.
Thanks,
Mike