OBVIOUSLY if police officer is committing a CRIME the footage of that crime is evidence enough, but I've seen many times cut up security footage of "cops harassing someone" only to see the full footage of the "someone" in question being the aggressor the whole time and then yelling about police brutality when he is apprehended and escorted into the police van.

We've witnessed this US LARP in my country just recently where protestors were nicely carried into police vans by the cops, but some intentionally went completely limb to hinder the operation and footage of these limb people getting dragged into the van was used as evidence of how brutal our police force is even though there was dozens of removals where people were carried without even touching the ground.