These games don't have streamed audio, as is usual in Nintendo titles. I supose all loop info is stored in the bcsar file, but I don't know how to reach it. Could someone share it or tell me how to seek it, in order to make custom looped files? Thanks!
X/Y does have streamed files. It uses .aac, which is hilarious. I'm almost positive we have determined that the loop points are in the .bcsar, but I don't think there's any way to edit them other than knowing where they are and hex editing them manually.
I find the X/Y rip weird. Especially how some of them even have a kind of ending. For example the "Battle (Mewtwo)" thing, after the loop usually ends, there's a bit where it just has the percussion, with the weird sound at the beginning... or something.
If it's there, it'll be in the sound table from the INFO section of the bcsar. I'll check at some point to confirm if loop information is stored in bcsar/bfsars, though I don't know for sure.
Probably nobody on here at least. There's really no need for it since the soundtrack was released not long after the game (in much higher quality as well).
I actually manually looped the X&Y OST's audio myself, although it did take a little while to convert everything. Not sure if I want to share it publicly though because I don't feel comfortable dealing with possible legality issues or something related. (I don't know if sharing looped OSTs has more consequences or something than sharing game rips. I could be totally wrong.)
Actually, you could try checking Smash Custom Music to see if X and Y audio is looped on there (once the site is back up).