The PTO issues new patents on Tuesdays. Both of today's Spotlight Patents concern aspects of digital watermarking. Assigned to Limelight Networks, the first of today's patents addresses techniques for the unique watermarking of content objects according to end user identity. Assigned to Broadcom, the second patent addresses techniques for robust watermark insertion and extraction for digital set-top boxes.
8,806,558, "Unique watermarking of content objects according to end user identity," assigned to Limelight Networks.
A machine-implementable method for uniquely watermarking a content object according to end user identity includes transcoding an original content object to a format that is compatible with end user systems, and storing the transcoded content object where it is accessible by one or more points of presence (POPs) of a content delivery network. One of the POPs receives identifying information associated with a specific one of the end user systems. A digital watermark engine adds uncorrected digital watermark information correlating to the end user system, to the content object, to form a uniquely watermarked content object. The uncorrected digital watermark information is correctable by error correction capability of the specific end user system to deliver a version of the content object that is indistinguishable by a human from the original content object. The method further includes transmitting the uniquely watermarked content object to the specific end user system.
8,806,215, "Method and system for robust watermark insertion and extraction for digital set-top boxes," assigned to Broadcom.
Methods and systems for robust watermark insertion and extraction for digital set-top boxes are disclosed and may include descrambling, detecting watermarking messages in a received video signal utilizing a watermark message parser, and immediately watermarking the descrambled video signal utilizing an embedded CPU. The embedded CPU may utilize code that may be signed by an authorized key, encrypted externally to the chip, decrypted, and stored in memory in a region off-limits to other processors. The video signal may be watermarked in a decompressed domain. The enabling of the watermarking may be verified utilizing a watchdog timer. The descriptors corresponding to the watermarking may be stored in memory that may be inaccessible by the main CPU. The watermark may comprise unique identifier data specific to the chip and a time stamp, and may be encrypted utilizing an on-chip combinatorial function.