Make the cops prove it with video evidence?

Doesn't help against it being selectively enforced, only against it being used for false accusations.

Oh great, nonstop video surveillance of pedestrians. I don't like that either.

Isn't that a bridge that's already been crossed?

It's one thing to have street cameras that are used to investigate serious crimes, or to help direct first responders.

It's another to regularly use that camera footage for petty crimes like j-walking or cell-phone-walking.

But we don't really just have "street cameras that are used to investigate serious crimes." We have police driving around taking photos of everyone's license plates, allowing them to keep track of where everybody goes; sophisticated facial recognitions; etc.

If cops are charging people that didn't even commit a crime then selective enforcement isn't really your biggest problem.