Let's say you like the jungle. You have a few Survivor episodes and Predator movies. You'd like to separate the jungle clips from clips involving humans. Maybe to play as a projector show at a party, or so.
My first thought: many shows and movies are hysterically chopped up in shots. As such a shot shift is often dramatic in terms of on-screen data change, they could be detected, and then each shot saved as a separate file. This will take some time, but when it's done you could manually sort out the jungle.
But, some jungle would be lost because some shots slide from jungle to human, or from human to jungle.
Then I thought, some digital cameras are able to spot humans and instantaneously give them focus. If I had that, I could simply drop all frames with humans.
Do you know of such software?