Voice-over (also known as off-camera or off-stage commentary) is a production technique where a voice—that is not part of the narrative (non-diegetic)—is used in a radio, television production, filmmaking, theatre, or other presentations.[1] The voice-over may be spoken by someone who appears elsewhere in the production or by a specialist voice actor. It is pre-recorded and placed over the top of a film or video and commonly used in documentaries or news reports to explain information.