It amazes me how when articles like this are posted on "conservative" sites, there is always a contingent who jump up and decry "cop haters!"
Seems that the cops (the bad ones, anyway) fear a camera worse than guns. Thuggish and pitiful. My advice is to be sure your phone has a "record" button on it and have it going whenever you are approached by police. You don't need to be open and blatant about it. In fact, it would be better if you simply recorded it without anyone knowing.
The vast majority of cops are good guys. Cameras and recorders help the rest of them.