Teletext / Videotext is an information retrieval service provided by television broadcast companies, most popularly in Europe, which provides both informational pages and captions or subtitles to television programs. In 1992, teletext was provided in 18 countries.
In the PAL standard, Teletext and Caption data is digitally encoded in the VBI on lines 17 through 20.
Digital television (DTV)
The European standards ETSI EN 300 472 "Specification for conveying ITU-R System B Teletext in DVB bitstreams" and ETSI EN 301 775 "Specification for the carriage of Vertical Blanking Information (VBI) data in DVB bitstreams".
The DVB standard transmits sliced VBI data in a separate elementary stream.