US Patent 7779271 Watermark embedding

Advanced watermark embedders use psycho visual/acoustic models to minimize perception of the embedded watermark in media contents. However, it is expensive to implement such advanced watermark embedders in consumer appliances (3) such as DVD recorders. In accordance with the invention, embedding strength parameters (JND) are calculated (13) off-line at a remote location (1) and transmitted along with the media contents to the consumer appliance (3). A relatively simple embedder (33) uses the received parameters to control the strength of the watermark (36) to be embedded. The parameters may be accommodated in the transmitted signal as payload of a fragile watermark or as user data in an encrypted MPEG stream.