if the time delay between you posting the video and him filing the complaint was greater than 60 days you could most likely have gotten away with posting it from your home connection without being tracked, for something this minor at the most they will subpoena youtube, who will tell them the posting ip, then they subpoena the isp that was assigned that ip on that day, and if the subpoena was submitted more than 60 days later (some go out as long as 90) the isp tells them to go jump in a lake they don't keep that info for that length of time. in the future, don't use tor, use a mac addy spoofer for your wireless (or a cash bought disposable wireless antenna, big lots sells em for $10) and use the best proxy in the world...starbucks
Edited to fix spelling and add:
by the way, youtube charges a subpoena compliance fee, and so does the isp most likely, so he'd have to throw a couple hundred bucks at this to even get it looked at (in addition to hiring a lawyer, the most damning evidence against you is your own reaction, and that is most likely the only thing he could possibly bring to bear against you in court)