No, today's compression is about compressing what's already in the one movie. But imagine that you run your training set over 100's or 1000's of films, and extr

No, today's compression is about compressing what's already in the one movie. But imagine that you run your training set over 100's or 1000's of films, and extract just enough to represent say different types of trees in a few bytes. You could 'compress' a film by replacing data with markers that essentially describe some properties of the tree, and those properties + the training set are then used during 'decompression' to recreate (an approximation of) the tree. This would of course not give you any space savings when you want to distribute 1 movie. There would be some minimum number of movies where the training set + actual movies would be smaller than the sum of the sizes of the individual movies compressed. I'm not saying this would be a net space saver, or necessarily a good technique at all, but the concept is intriguing.