Is it technologically possible to translate video and audio on the fly?

Technically yes but Google's translation page is about as good as the translations as you are going to get -- and try for example translating the lyrics to one of Cesaria Evora's songs even if they are in Cape Verdean Creole. There is nothing to say this sort of thing is unfeasible but the level of machine translations we are willing to accept is very low. It is not generally a good idea.