SGML for access: No/Yes

for readers who do not know much about access technologies but do know something about SGML

First, definitions:

Captioning

Rendering dialogue and other sounds in visible words. Sign language has nothing to do with captioning. Nominally, only time-based media like TV and film (and CD-ROMs and the like) can be captioned, but it's possible to caption radio or other audio-only telecasts and live plays.

Closed-captioning

Captions transmitted in the form of a code. You need a decoder (or, more likely, just a decoder chip) to turn the captions into visible words. Nearly all North American TVs carry decoder chips as standard equipment now. Before built-in decoders were required by law, you needed an external decoder, which are still available in declining supply. For captioning in PAL- and SECAM-standard countries, you generally need a special teletext television; captioning is merely one aspect of the general teletext service.

Open-captioning

Captions that are an indelible part of the picture and are always visible. (Open-captioning effectively does not exist anymore, and in fact the number of hours of open-captioning produced in the history of the world is inconsequential compared to the hours of closed-captioning produced in the world in a single week. It is assumed, on the basis of no scientific studies whatsoever, that hearing people simply will not tolerate open-captioning.)

Note: Captioning and subtitling have as little in common as bicycles and motorcycles. Three big differences are:

• Captions are in the same language as the audio (with relatively rare exceptions).
• Captions denote sound effects meaningful to the narrative or to understanding the program.
• Captions move to indicate the position of the speaker.

Subtitles are a translation, ignore sound effects, and are always located in the same spot on-screen.

Audio description

Rendering visual details in a spoken narrative. In audio description, a special narrator succinctly describes action, settings, facial expressions, onscreen graphics, clothing, and other visual details. The narrator speaks out loud; A.D. is an auditory medium, not a visual one. Narrators typically speak during pauses in dialogue or at other appropriate moments, but sometimes they narrate over dialogue, over music, and so on.

How does this relate to information technology and SGML? The Common Issues homepage tells more.