Welcome to America.
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 in court, 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.
Basically, if you are videotaping police officers (they could be abusing their power, it doesn't matter), you can get arrested and go to jail for 4 - 15 years.