Letterboxing (filming)

Letterboxing is the practice of transferring film shot in a widescreen aspect ratio to standard-width video formats while preserving the film's original aspect ratio. The resulting videographic image has mattes (black bars) above and below it; these mattes are part of each frame of the video signal. LBX or LTBX are identifying abbreviations for films and images thus formatted.

A 2.35:1 widescreen image letterboxed in a 1.33:1 screen