Widescreen films do not easily fit onto standard 4:3 screens, so the film industry developed a technique to scan the film and select the most important part of the frame for transfer to video. Because the important part of the frame is not always in the center, a technician must "pan" back and forth in the frame to follow the action. Effectively, each frame is cropped to the 4:3 aspect ratio and image falling outside that field is discarded.
Aspect ratio down conversion with full vertical screen occupation and on-line control of horizontal centering. Synonyms: PanScan
(aka Full Screen) - A process by which significant action in film is determined on a shot-by-shot basis, and less significant parts are eliminated to fit onto a television-sized screen. A way of compensating for television's narrow aspect ratio when transferring film to video. Contrast with Letterboxing.