That's why Google filed a patent application, Detecting Repeating Content in Broadcast Media (20070124756), which the USPTO published yesterday.
There are multiple aspects to the patent application, but I'll highlight only a few by taking text verbatim from the specification.
- Video Ad Removal: One of the complaints that broadcasters have had about allowing material to be searched and played back is the rebroadcast of embedded advertising. From the point of view of the broadcasters, this rebroadcast is counterproductive: it lowers the value of the broadcasts that the advertiser pays for directly, since it provides that advertiser with free advertising. Unless old advertisements are removed and new advertisements are put in place in a way that returns some review to the original broadcasters, they do not profit from the replay of their previously broadcast material. The process 700 described below provides a way of detecting embedded advertisement by looking for repetitions, possibly in conjunction with other criteria (e.g., duration, volume, visual activity, bracketing blank frames, etc.).
- Audio Snippet Auctions: In some implementations, advertisers can participate in auctions related to the presence of ambient audio that is related to the product or service that the advertiser want to sell. For example, multiple advertisers could bid in an auction for the right to associate its products or services with an audio snippet or descriptor associated with "Seinfeld." The winner of the auction could then put some related information in front of the viewer (e.g., the sponsored links) whenever the subject ambient audio is present. In some implementations, advertisers could bid on ambient audio snippets having a meta-level description. For example, advertisers could bid on audio that is associated with a television ad (e.g., this is the audio associated with a Ford Explorer TV ad), on closed captioning (e.g., the captioning says "Yankees baseball"), on program segment location (e.g., this audio will occur 15 min into the "Seinfeld" and will occur 3 minutes after the previous commercial break and 1 min before the next commercial break), or on low-level acoustic or visual properties (e.g., "background music," "conversational voices," "explosive-like", etc.)