Audio description refers to an additional narration track for blind and visually impaired viewers of visual media, including television and movies, dance, opera, and visual art. For simplicity, this article focuses on the most common venues for description: TV and film. The description narrator talks through the presentation, describing what is happening on the screen during the natural pauses in the audio (and sometimes during dialogue if deemed necessary). In fiction, a narrator is a voice or character who tells the story. ... Blindness can be defined physiologically as the condition of lacking visual perception. ... Blindness can be defined physiologically as the condition of lacking sight. ... Film refers to the celluloid media on which movies are printed Film is a term that encompasses motion pictures as individual projects, as well as the field in general. ... A contemporary dancer rehearsing in a dance studio Dance (from Old French dance, further history unknown) generally refers to human movement either used as a form of expression (see also body language) or presented in a social, spiritual or performance setting. ... The foyer of Charles Garniers Opéra, Paris, opened 1875 Opera is an art form consisting of a dramatic stage performance set to music. ... Many times, the term art is used to refer to the visual arts. ... See TV (disambiguation) for other uses and Television (band) for the rock band European networks National In much of Europe television broadcasting has historically been state dominated, rather than commercially organised, although commercial stations have grown in number recently. ... Film refers to the celluloid media on which movies are printed Film is a term that encompasses motion pictures as individual projects, as well as the field in general. ...

On NTSC-format television in North America, audio description is usually transmitted on the secondary audio program (SAP). However: NTSC is the analog television system in use in the United States and some other places, mostly the Americas (see map). ... It has been suggested that Northern America be merged into this article or section. ... Second[ary] audio program[ming] (SAP) is an auxiliary audio channel for television that can be broadcast or transmitted both over the air and by cable TV. It is often used for an alternate language (hence giving the facetious Spanish audio program expansion to the acronym), or for the Descriptive...

• SAP must be turned on to hear the descriptions, which are pre-mixed with the original soundtrack.
• The sound is monaural and not very good, but it works.
• The visual interfaces used to turn on SAP are a problem for blind people.
• There are many technical impediments that pop up from time to time and interfere with passing through a SAP signal on cable and satellite systems.

Pure-digital services (as on satellite and digital cable TV) cannot transmit Second Audio Program. Some satellite and digital-cable platforms offer multiple audio tracks using proprietary systems, and an original SAP channel can be mapped onto one of them. Nonetheless, in practice it is difficult for viewers at home to watch descriptions recorded on SAP via satellite or digital cable unless the satellite or cable operator takes extraordinary measures. Monaural sound reproduction is single channel. ... In general usage, an interface is the point, area, or surface along which two substances or other qualitatively different things meet; it is also used metaphorically for the juncture between items. ...

In all broadcast systems in North America, blind and visually-impaired viewers face the accessibility obstacle of having to turn the description track on and off using visual menu systems they can't see.

Audio Description (AD) on Digital Terrestrial Television in the United Kingdom is delivered on a separate track making it possible to adjust the AD volume separately from that of the audio from the television programme. Most people receive Audio Description via digital satellite television however, as you don't need to buy a special box and can just select Audio Description (or Narrative) via the menus on your satellite set-top box. On satellite television]] the AD soundtrack is pre-mixed - the traditional way of experiencing description through your TV. Digital Terrestrial Television (DTTV or DTT) is an implementation of digital technology to provide a greater number of channels (SDTV) and/or better quality of picture (EDTV, HDTV) and sound (AC3, Dolby Digital) through a conventional aerial instead of a satellite dish or cable connection. ...

In movie theaters, audio description can be heard using DVS Theatrical and similar systems (including DTS-CSS and Dolby Screentalk). Users listen to the narrator on a wireless headset. Wireless was an old-fashioned term for a radio receiver, referring to its use as a wireless telegraph. ... Headset may refer to: headset (earphone, headphone) headset (bicycle part) This is a disambiguation page — a navigational aid which lists other pages that might otherwise share the same title. ...

DVDs very rarely include audio description using one of the eight audio tracks available on DVD-Video discs. However, the visual interface used to turn the description track on or off can be inaccessible to a blind person. // DVD is an optical disc storage media format that can be used for storing data, including movies with high video and sound quality. ...

External links

• Joe Clark on audio description
• ADI - Audio Description International