1. A method comprising: receiving from a server into a local cache on a computing device a signature file of fingerprints of media content and corresponding identifiers of the media content after the computing device sends one or more initial fingerprints determined from a media stream by the computing device, wherein the fingerprints in the signature file are for features anticipated to appear in the media stream at predetermined times; and the computing device using the cached fingerprints of media content in the signature file to identify a media content item within the media stream based on one or more additional fingerprints determined from the media stream.