http://copwatcher.info/2014/03/video-recording-police/
Above is a great link to a video and in depth discussion of the legality of recording police on duty. Several different cases of recording police conduct are discussed and video is provided.
Despite some law enforcement agencies claims, it is legal to record police in public in all 50 states as long as you are not intering with the performance of their duties. What constitutes interfering with police is open to debate and advice and tips are given by Cato.org as well as CopWatcher.info.
Make sure you are recording in a public place, as opposed to private property not accessible by the public or in an active crime scene. Also make sure you stay a safe distance away from police while they do their job. Not only is it distracting to them to have someone in their personal space, it is a legitimate safety issue for police. Police by nature are suspicious of everyone, and to an extent they have to be. As a result they do not want anyone nearby when they encounter a suspect. Police most likely do not know who you are and if you might end up being a threat.
Police also have a responsibility to provide a certain level of privacy to both suspects and victims. Certain personal identifying information can not be released to the public among other privacy concerns. A video recording of a sexual assault victim being interviewed by police posted on Youtube could pose legal issues for police. So use some common sense and decency when recording. Also use some discretion if a police officer asks you to stop recording. He may not be in a position to explain to you the exact nature of the request.
