It's best not to use another film.
One of the kids at my school did it, even with another related, but the teacher still wasn't happy.
The best and easiest ones to do are photographs or paintings. try to stay away from ads because their main purpose is to make a profit, not to send out a message (except that their product is the best)
Also, you can do anything with photos and if you make a mistake, it is likely the teacher won't even know what text it is! As if the people marking the HSC are going to search up every piece of related material they get in order to find if what you're saying is correct!
Novels are also good, but my teacher says that you really need to know how to do it though. There's a lot of people who do novels and end up stuffing it up. I'm doing a novel, Picture of Dorian Gray, by Oscar Wilde. Needless to say, I've been doing like a million essays for my teacher to mark, and she's still not happy with it! But I'm sticking with my choice because it is one of my favourite books of all time!!!