Digitalisation of cable, satellite and terrestial television networks within Europe is based on the Digital Video Broadcasting (DVB) series of standards and on the companion MPEG-2 standard used for digital video and audio transport (including compression to make more effective use of available bandwidth).
Within the DVB family there is a standard (ETSI EN 300 468) specifically for metadata, or Service Information (SI) as it called in this context. The standard allows for SI to accompany broadcast signals and is intended to assist the receiver/decoder and viewers to navigate through the growing array of digital services on offer.
Within DVB-SI, the Event Information Table (EIT) is especially important as a means of communicating programme ("event") information. For DVB compliance it is mandatory to provide information on the currently running programme and on the next programme. In addition there is the option of providing an EIT schedule with information further into the future and for more than one channel.
The EIT can be used to give information such as the programme title, start time, duration, a description and parental rating. It is also possible to classify programmes using what are known as "content descriptors". These are drawn from what is, in effect, a two-level genre list (the top level consisting of ten broad programme categories - movie/drama, news/current affairs, show/game show etc. - within each of which there are from 7 to 18 sub-categories).
Although DVB-SI is currently the most widely implemented TV metadata standard, its full potential is far from being realised. Often only the mandatory minimum information is provided. Full use is not made of the descriptive tools that DVB-SI makes available. Programmes are often not classified using content descriptors and information is only provided on the present and following programme/event - rather than for several days ahead and multiple channels. As a result many viewers are not watching programmes that they would otherwise have watched. They don't even know that they exist.