There's no provision for flight crew to use the erase feature of the CVR (especially nowadays with 25h CVRs), why would it be different with video recorders?
Not sure what you mean by "provision" but the erase button deletes the entire recording as long as the aircraft is on the ground and the brake is set (A320), it was the only way any of the pilot unions would agree to having them. I would expect that any cockpit video recorder would offer the same facility.