I would imagine it's simply a temporal comparison of pixel colors at predetermined locations, similar to how the Shazam algorithm[1] works? You'd just need to a

I would imagine it's simply a temporal comparison of pixel colors at predetermined locations, similar to how the Shazam algorithm[1] works? You'd just need to analyze enough pixels to reduce "collisions", coupled with the temporal aspect! [1] https://www.ee.columbia.edu/~dpwe/papers/Wang03-shazam.pdf https://www.ee.columbia.edu/~dpwe/papers/Wang03-shazam.pdf