CONTENT IDENTIFICATION FOR BROADCAST MEDIA

摘要

A method and apparatus for repeatedly embedding content identification information ('identifiers') into a media data stream, such as an MPEG video data stream. The identifiers are embedded into the data stream using a hash function that binds an identifier with a rapidly varying property of the data stream so that it is difficult for an unauthorised device to insert false identifier information or to edit the identifier information. The identifier may be secured also with a digital signature. The method and apparatus also provides for transcoding of the data stream and re-calculation of the embedded identifier, by an authorised device, where the rapidly varying property of the data stream may be altered by the transcoding operation.