What you can say is if there are N videos and k types of transforms that are used to "hide" content this would be hypothetically perfect with O(n + k) train exa

What you can say is if there are N videos and k types of transforms that are used to "hide" content this would be hypothetically perfect with O(n + k) train examples - naive "reporting only" would be O(nk). This means that you should just need one example of each transform and one known instance of a particular copyright infringing media in order to get high performance. Mirroring etc. would just be one example of the transforms an approach like this would be robust to. It's hard to say what the error rates will be, but you should be on the last 5-10% Pd/Pfa pretty much instantly and then if you want more you can just acquire more true labelled data (if a user can find a copyrighted video on your site, I would think a contractor could, too!).