Editing Closed captioning (section)

==== Technical aspects ====
There were many shortcomings in the original Line 21 specification from a [[typography|typographic]] standpoint, since, for example, it lacked many of the characters required for captioning in languages other than English. Since that time, the core Line 21 character set has been expanded to include quite a few more characters, handling most requirements for languages common in North and South America such as [[French language|French]], [[spanish language|Spanish]], and [[portuguese language|Portuguese]], though those extended characters are not required in all decoders and are thus unreliable in everyday use. The problem has been almost eliminated with a market specific full set of Western European characters and a private adopted [[Norpak]] extension for [[South Korea]]n and [[Japan]]ese markets. The full [[EIA-708]] standard for digital television has worldwide character set support, but there has been little use of it due to [[EBU]] Teletext dominating [[Digital Video Broadcasting|DVB]] countries, which has its own extended character sets.

Captions are often edited to make them easier to read and to reduce the amount of text displayed onscreen. This editing can be very minor, with only a few occasional unimportant missed lines, to severe, where virtually every line spoken by the actors is condensed. The measure used to guide this editing is words per minute, commonly varying from 180 to 300, depending on the type of program. Offensive words are also captioned, but if the program is censored for TV broadcast, the broadcaster might not have arranged for the captioning to be edited or censored also. The "TV Guardian", a television [[set-top box]], is available to parents who wish to censor offensive language of programs—the video signal is fed into the box and if it detects an offensive word in the captioning, the audio signal is bleeped or muted for that period of time.