1. A method for replacing a portion of a video stream with a targeted advertisement, the method comprising: receiving a video stream at a set-top box; continually creating statistical parameterized representations for windows of the video stream at the set-top box; continually comparing the statistical parameterized representations to windows of a plurality of fingerprints, wherein each of the plurality of fingerprints includes associated statistical parameterized representations of known video content; detecting the known video content in the video stream when a particular fingerprint of the plurality of fingerprints has at least a threshold level of similarity with the statistical parameterized representations; selecting the targeted advertisement based on the known video content; and replacing the known video content in the video stream with the selected targeted advertisement when the known video content has been detected.