There's an article in the Chronicle of Higher Ed. (subscription) about how human indexers at USC have indexed every minute of the 120,000 hours of Holocaust testimony in the Shoah Foundation Institute for Visual History and Education's video collection. It is one of the most comprehensively indexed video collections of its size. The indexing allows researchers to search for various topics through keywords and gain access to the testimonies at the very moments that those topics begin to be discussed.
USC hopes that the institute's labor-intensive, manual method will be a model for other video archives. Video isn't much use as a research tool unless it is indexed. The method of indexing the tapes in one-minute segments and using keywords has been patented, and the university plans to market the patents to other archives. The technology has already been licensed to the state archives of Italy, which is processing video in its holdings.
You can see how the online search of the collection works in the Testimony Catalog.