Searching TV Programs Using Teletext Subtitles
Many TV programmes have accompanying TeleText subtitles, and this offers an opportunity to find footage by searching for keywords in the subtitles.
Ahe Subtitles Search System deals with the problem of finding all the relevant documents in a video collection of TV programs for a given user's query.
The purpose of a video document retrieval system is to automatically index and then retrieve relevant items from a large collection of video recordings in response to a user query. The video documents will be TV programme with accompanying subtitles.
Potential users of the system are likely to watch video on their computer instead of on their TV, examine individual clips within program store rather than entire programs. This project is a step towards Video On Demand (VOD) and interactive TV. Customers can watch video whenever and whatever they want. However VOD and iTV are still a long way too go.
Though devices like the Tivo can time-shift TV and record it, they can only hold 30 hours. The web, especially with a broadband connection, can hold unlimited amounts of video.
To retrieve desired information from such huge video repositories, a search engine is demanded. Some cursive video search web sites are based on videos' description. Either a trailer of a relevant film or a complete version is playbacked as one result. User cannot skip around in the movie and find the scene they are interested.
Since many television programmes (more than 70%), movies on DVD and pre-recorded video tapes have specially coded closed caption subtitles, the feature that interests deaf and hard of hearing users, makes feasible to search by keywords in the subtitles without any requirements on voice or image recognition.
On television programs, subtitles are provided on teletext page 888. It is available on ITV, Channel 4, Channel 5 and BBC1 and 2. Both programs and their accompanying subtitles can be captured by a TV card installed on a workstation. It's possible to use currently available devices to get video source and subtitles as well and develop a web-based search engine for video documents, enabling users to access specific program clips in response to the keywords they input.