that video was legal to make in Maryland

This is the second time recently that a Maryland cop got in trouble thanks to video evidence - in the other case, a camera phone recorded a cop attacking a pedestrian without provocation (and of course the pedestrian was charged with attacking the police officer, before the video surfaced - which combined with a similar incident captured on film in New York lately makes me wonder how many people are currently in jail for the crime of being attacked by a cop).

However, the law in Maryland only covers cases where at least one party has an expectation of privacy, which does not include on-duty cops (except perhaps when they are in the restroom taking a leak). The law and the courts have been clear, but some of the police there, used to being "untouchable", are deliberately misinterpreting the law so that they can harass this guy.

My understanding is that the only state where videotaping on-duty police officers is a crime is Illinois, where the state legislature was careful to write a law just for that purpose. Of course, Illinois is also notoriously corrupt (second only to Louisiana) and their police forces especially so.