The police have to deal with a terrible amount of abuse. Due to years of police "reform" by liberals they now have very few legal and physical methods to defend themselves. It's this reduction of their powers that have made them so useless and unfit for purpose, and is one of the two main reasons why crime is soaring. Having more of the same type of police officers will not make much difference; giving the police greater powers will make a difference.
Filming the police is just another liberal method of restricting them. In these film clips we see no background; we do not know what has happened beforehand, what might be happening out of shot, and most importantly we don't know the criminal record of the people being apprehended.
The abuse the police receive, is a symptom our modern culture which has a lack of respect for authority, including parents, teachers, police, paramedics etc.
Of course there is some level of police violence, but its miniscule compared to the abuse they get daily.
I know a policeman, used to work in Brighton: he said over 75% of crime he dealt with was drug related....so that doesnt help either