Widescreen is the display format of a motion picture with an aspect ratio of 1.78:1, which corresponds to a 16:9 display. This format is optimized for the human field of view and is used in HDTV, Ultra-HDTV, in PALplus and in DigitalVideoBroadcasting( DVB).
The wider cinema format has an aspect ratio of 21:9, or 2.35:1, and is referred to as ultra widescreen. Cinema films shot in the widescreen format with an aspect ratio of 2.35:1 are shown on widescreen displays (16:9) with black stripes at the top and bottom of the screen. Transmissions in 4:3 format are displayed with black bars on the right and left edges of the screen. If, on the other hand, the widescreen format is displayed on a 4:3 screen, it appears compressed horizontally.