Video search is the latest battleground on the web, as broadband brings more audiovisual media online, with significant implications for other interactive video services.

The technologies that are now being demonstrated on the web could also become crucial to the navigation of content for video-on-demand and broadband television.

Blinkx, which produces a desktop search tool for personal computers, has revealed an online search engine that scans broadcast television channels and online streams.

Using a combination of techniques, including speaker independent speech recognition, blinkx TV claims to watch, read and listen to audio and video signals in real time to build metadata tracks that are synchronized with the associated digital media.

The company says that unlike keyword based approaches, blinkx ‘thinks while it links,’ using what it calls context clustering to support conceptual searches. This allows users to search television, radio and the web for relevant clips.

“At blinkx we’ve recognized consumers’ needs and taken the search engine to a new level. Ground breaking automatic transcription technology, which transcribes content straight from the cable box on the fly or from video already stored on the web, together with advanced phonetic matching speech recognition technology, automate the process of searching TV clips for the first time,” said Suranga Chandratillake, who founded blinkx after leaving Autonomy where he was chief technology officer.

“Rich media, like video, is the next step in the evolution of search from web, to desktop, to living room,” according to Mark Opzoomer, chief executive of blinkx. He recently joined the company from Yahoo, where he was managing director in Europe.

Yahoo has also launched a beta release of its video search engine for the web. To combat the difficulties associated with searching for multimedia content online, Yahoo is proposing to support the RSS syndication format and is suggesting an optional set of metadata extensions. This metadata could include the names of the cast and crew, length of the program, licensing terms or available formats.

“Part of our strategy for video is to leverage the momentum of RSS and the community,” said Bradley Horowitz, director of multimedia search at Yahoo.

It will be interesting to see whether such an ad hoc approach gains grassroots support over more complex schemas such as TV-Anytime.

Although the approaches of blinkx and Yahoo appear to be quite different, they do have something else in common. Yahoo’s Bradley Horowitz was a founder of Virage, a company that developed video logging tools including speech recognition. Virage first launched a video search engine back in 2000. The company was subsequently sold to none other than Autonomy.

Meanwhile, Google has also been demonstrating its own search technology to broadcasters, thought to involve text searching closed caption subtitles. With Microsoft also believed to be working on a video search engine, you can expect blinkx to be the subject of considerable industry attention, if not an acquisition.