Yes!
The filming of government officials engaged in their duties in a public place, including police officers performing their responsibilities, fits comfortably within these principles. Gathering information about government officials in a form that can readily be disseminated to others serves a cardinal First Amendment interest in protecting and promoting “the free discussion of governmental affairs.”
US First Circuit Court (PDF) via The Agitator
This is huge. Common sense tells us there's no expectation of privacy for police officers on duty, but it's great to have cell phone videographers' rights officially affirmed.
