I have IOS 8.something (latest version for this genre iPad) and it normally plays all YouTube video, either through the app or through Safari. The other day I located a three or four year old series of videos on my PC, and decided to AirPlay them later for my wife to view on our TV using Apple TV. The videos would not play on the iPad --- no error message, just a spinning indicator in the middle of a dark screen that never resolved. The show is British, "Restoration House." What do I conclude about this? The video format on YouTube is/was incompatible with iPad? I thought all that Flash nonsense was converted on the fly so iPad could view all YouTube stuff. Anyone have an idea? Thanks.