Doesn't matter, the nice thing about software patents is that somebody somewhere could have a patent on using the number '2' in a video codec. And you never know until they get bought out by your enemy.
Of course, but the point is that if there is a submarine patent--On2 doesn't have it, someone else does, because On2 already disclaimed all of their rights.
And yes, video formats and encoders are notorious for incredibly trivial and retarded patents.
For example, Predicted_MV = Median(Left_MV,Top_MV,TopRight_MV) is patented.