Podzinger, a podcast search engine, now hunts down video files. It joins an increasingly crowded field of companies offering online video search, including AOL, Google, and Yahoo.

Podzinger claims it enables full-text search, compared to rivals that index data associated with audiovisual files such as text transcripts and metadata. "This is a critical differentiation," says Alex Laats, president of Podzinger. "Our whole premise is you have to be able to search inside the audio."

That's a distinction blinkx claims, too, for its blinkx.tv video search site. Blinkx's speech-to-text technology listens to all the words in a video and audio file and then automatically creates a transcript, says a company spokesperson.

However, neither Podzinger nor blinkx makes a full-text transcript available to users.

The indexes of searchable video and audio content return widely varying results. A search for "Dick Cheney" returned 35 results from Podzinger's video index, 50 results from blinkx, 51 from Google, 244 from Yahoo, and 372 results from AOL's Truveo.

More results, however, doesn't necessarily mean more relevant ones. Both Podzinger and Truveo returned links to adult sites--and Truveo had been set to exclude adult content.

One major difference between Podzinger and blinkx is that the former presents video excerpts and source segments in its search results window, where they can be played. The search links on blinkx open a new window that calls up the content distributor's site. Blinkx's approach may be slower because a new site has to load, but it's also more accommodating to owners of copyrighted content.

Laats suggests that full-text search of audiovisual files lets content creators better monetize their content by making shows more transparent to advertisers. He predicts strong growth in video-related advertising revenue in the months to come as a result of Podzinger's capabilities.

That may be a foregone conclusion now that Rocketboom, the pioneering video blog, got $40,000 for five 15-second ad spots during the week of March 6th from automated teller machine maker TRM. And Internet service provider EarthLink also signed up to run ads on Rocketboom.