To reformat a wide screen movie for a standard definition (SD) screen, which is more square. Prior to the advent of HDTVs, pan & scan was performed on many films for home viewing. It is no longer required today. See SDTV and HDTV.How It Was DoneAs the original movie was played, a technician decided which part of the scene was critical and moved an SD viewing window horizontally across the wide image to capture it.Since nearly half the original scene was missing with pan & scan, artistic elements were often degraded. For example, landscapes were always clipped, and when two important objects were at opposite ends of the frame, one was lost. Pan & scan eliminated the black bars at the top and bottom of the screen (see letterbox).Shoot Both FormatsIn order to avoid the extra cost of pan & scan, many wide screen movies were shot with a standard TV outline in the middle of the camera's viewfinder so that the director could keep critical objects in the center of the frame at all times. In that way, the movie could be automatically converted for standard TVs with 4:3 aspect ratios by truncating both sides automatically. See anamorphic DVD.