New patents are issued by the USPTO on Tuesdays. Today's Spotlight Patents address aspects of digital watermarking and digital fingerprinting. Assigned to MobiTV, the first patent concerns techniques for scalable watermark insertion for fragmented media stream delivery. Assigned to British Telecom, the second of today's patents concerns techniques for a digitally encoded video fingerprinting system.
9,330,429, "Scalable watermark insertion for fragmented media stream delivery," assigned to MobiTV.
A media stream is delineated into multiple fragments. Different watermark variants of individual fragments are generated. Particular sequences of watermark variants are selected for particular clients and maintained in a user access database. Analyzing media streams allows determination of the sequences of watermark variants and identification of particular clients intended to receive the media streams. Fragments can continue to be cached efficiently and unique watermarks need not be generated for each individual client.
9,330,426, "Digital video fingerprinting," assigned to British Telecom (GB)
A digitally encoded video fingerprinting system for generating and comparing/matching finger-prints from digitally encoded video which has been encoded according to an encoding method which involves the generation of residual macroblocks of pixels and the generation of quantized transform coefficients of the residual macroblocks, or of portions of the residual macroblocks, comprises a fingerprint database (5) and a video processing subsystem (10). The video processing subsystem (10) includes a fingerprint sequence selection module (14, 24) which is operable to select one or more sets of frames from input video content to be processed in order to generate a fingerprint; a fingerprint calculation module (14, 26) which is operable to generate a fingerprint based on a set of frames selected by the fingerprint sequence selection module; and a fingerprint comparator module (14, 28) which is operable to compare two fingerprints and to output a similarity score of the compared fingerprints. The method used by the fingerprint selection and fingerprint calculation modules includes selecting a group of frames of the encoded video content; processing the digitally encoded video content to obtain a set of quantized transform coefficients of residual macroblocks or portions of residual macroblocks associated with each of the selected frames; identifying a set of residual macroblocks per frame whose transform coefficients satisfy a threshold criterion; and generating a digital video fingerprint for the encoded video content in dependence upon the identified macroblocks or some property thereof within each of the selected frames.