If he had not had that camera, he would of got maced, then tazered.

He would of got his day in court. Policeman would of denied or downplayed his dialogue, his buddy would of corroborated, and he would of spent the weekend in jail, probably got a couple hits with the baton, fined and a record of disorderly conduct, resisting arrest just to name a few.

His knowledge didnt win that, the camera did, just have someone always around video taping, and collectively other 3rd party witnesses.

Good luck.