Weird, I've made a few videos of JPop Rock Band custom charts and I've never gotten copyright issues. The only videos I've got a notice on are Roar (GSL OP) and Lion (Macross OP); nothing happened to Lion and the only thing that happened to Roar was that it got blocked in Germany. I even put the actual song mp3s directly over the videos and YT only complained on those two occasions, and I've yet to get anything taken down.
Anyway, the Fair Use clause should be able to get you through any copyright claims (unless you are somehow making money off of them). You should be able to contest a claim put on a video.
Anyway, the Fair Use clause should be able to get you through any copyright claims (unless you are somehow making money off of them). You should be able to contest a claim put on a video.