USC SCA is extremely hard to gain admission to for its undergraduate majors. The acceptance rates are in the range of 4-6% I believe. Basically, you have to gain admission twice… being accepted generally by USC as the overall university and also swaying the SCA (School of Cinematic Arts) admissions’ staff/faculty. Gaining similar admission to graduate level programs at USC SCA is only going to be harder (or at least as difficult) and will require a significant creative portfolio, especially related to filmmaking production or screenwriting, based on your declared interests. I would thus suspect that a film and media studies undergraduate major is not going to be sufficient alone, absent a tremendous amount of extra work on your part to craft the prerequisite portfolio that they will expect to be seeing from you. If you truly are thinking about pursuing an MFA in either production or screenwriting, I would instead encourage you to apply to programs where the degrees are geared more specifically toward one of those areas… and not just an area concentration in film/media studies or the like. You could potentially spend a few semesters deciding on which major to declare, but I would then graduate from an undergraduate program with something more fine-tuned than just a generalist degree, like media studies.
Websites like CollegBoard.com offer college searches where you can differentiate between those type of majors and specifically locate schools that teach film/tv production (like USC, FSU, UMiami, etc) or screenwriting versus just more general degree categories.
You can certainly pursue a more diverse degree like film/media studies, but if USC SCA is truly your goal for an MFA program, a more specialized education could serve you better. At least that is my opinion.
Good Luck…