The camera belonged to a photographer working for TMZ.com, which posted the video, TMZ Managing Editor Harvey Levin said Monday.
The 47-year-old actor was leaving a restaurant Sunday night, according to TMZ, when he was surrounded by paparazzi. He's seen chatting amiably with them as he walks to his car, when one begins shouting insults.
He looks into the video camera of a TMZ photographer, says "Excuse me," and slaps the lens.
"What are you hitting me for?" the videographer shouts, adding he wasn't the one yelling at Garrett. "You hit my face with that," he says as Garrett gets in his car to leave.
Levin said the man suffered minor injuries, including a swollen eye.
Garrett's manager, Glenn Robbins, didn't immediately respond to an e-mail seeking comment.
Levin said TMZ wouldn't press charges because the camera wasn't damaged.
Garrett won three Emmy Awards for his role as Ray Romano's brother, Robert, on CBS' "Everybody Loves Raymond."