It is legal in MA to video tape anyone without audio, this includes police officers.
In response to a flood of Facebook and YouTube videos that depict police abuse, a new trend in law enforcement is gaining popularity. In at least three states, it is now illegal to record any on-duty police officer.
Even if the encounter involves you and may be necessary to your defense, and even if the recording is on a public street where no expectation of privacy exists.
The legal justification for arresting the "shooter" rests on existing wiretapping or eavesdropping laws, with statutes against obstructing law enforcement sometimes cited. Illinois, Massachusetts, and Maryland are among the 12 states in which all parties must consent for a recording to be legal unless, as with TV news crews, it is obvious to all that recording is underway. Since the police do not consent, the camera-wielder can be arrested. Most all-party-consent states also include an exception for recording in public places where "no expectation of privacy exists" (Illinois does not) but in practice this exception is not being recognized.
Massachusetts attorney June Jensen represented Simon Glik who was arrested for such a recording. She explained, "[T]he statute has been misconstrued by Boston police. You could go to the Boston Common and snap pictures and record if you want." Legal scholar and professor Jonathan Turley agrees, "The police are basing this claim on a ridiculous reading of the two-party consent surveillance law - requiring all parties to consent to being taped. I have written in the area of surveillance law and can say that this is utter nonsense."
In 2001, when Michael Hyde was arrested for criminally violating the state's electronic surveillance law - aka recording a police encounter - the Massachusetts Supreme Judicial Court upheld his conviction 4-2. In dissent, Chief Justice Margaret Marshall stated, "Citizens have a particularly important role to play when the official conduct at issue is that of the police. Their role cannot be performed if citizens must fear criminal reprisals…." (Note: In some states it is the audio alone that makes the recording illegal.)