[tedunangst]

I'm surprised whatever feature detection they use isn't robust against trivial changes like that. Rotation, flipping, and scaling/cropping should all result in the same hash.

[viewer5]

We only brushed over how hashes work in college, so I may be totally ignorant, but-- wouldn't rearranging the order of the data (rotate, flip, etc) necessarily change the resulting hash?

[icebraining]

They don't use those hashes, they use content fingerprinting: http://en.m.wikipedia.org/wiki/Digital_video_fingerprinting