At what point are you legally obligated to pay royalties

[jaguar]

And if this thing is going to touch TV, then trust me, they will track you down. There are people here in LA whose whole job is to watch TV channels from around the world and keep track of every single piece of intellectual property that gets used.

Boy that sounds like a stimulating career option. If it's old enough it might be in public domain but the media industry is doing it's best to snuff out such commie pinko concepts.