Streamsage has this technology (Score 1)

The folks down at Streamsage have been working on this for a while now. They are working on an index of NPR, last I heard. They do video and audio; a search retrieves the relevant clips of video. It works really well, apparently. This will be a fantastic boon for universities who have all kinds of lectures on video with no way of knowing where to find the information a student needs.