Definition: closed captions

Textual notations for the deaf at the bottom of the screen of TV programs and DVDs. Unlike foreign subtitles, which are created for people who can hear but not understand the spoken language, closed captions must include text that describes periodic background noises such as a barking dog, a sudden, loud noise from a vehicle or a gunshot.

Closed captions are created for DVD programs by importing the text as subtitles into the DVD authoring program. For video streaming, the closed captions text is linked with the video. For example, MAGpie (Media Access Generator) from the National Center for Accessible Media (http://ncam.wgbh.org) is software that synchronizes closed captions text with video files for streaming over the Web.