Digital Watermark Technology Announced by DVD Group

On Tuesday, February 16, five major computer and consumer-electronics companies---Hitachi, IBM, NEC, Pioneer, and Sony---announced that they have achieved an acceptable copyright-protection system for digitally reproduced movies and videos. The five companies are original members of the 11-member Copy Protection Technical Working Group (CPTWG), which has been at work on the problem for two years under the auspices of the DVD Forum.

The group has finally endorsed a "digital watermark technology," which implants an invisible mark in the picture. The companies did extensive research with expert viewers to find a system that would be transparent to users. The watermarking technology can be scaled to allow a video to be copied once, many times, or not at all, depending on the nature of the copyright. The new copy-protection system is functionally similar to the Serial Copy Management System (SCMS), which has been in place in consumer DATs for many years.

Technical details of the newly accepted system weren't released with the announcement, and IBM Vice President Dan Sullivan spoke only generally in his remarks: "Part of the data in the mark is copy-control information. It says the image is copyrighted, so do not copy; copy it once; or copy as many times as you like."

The hardware industry has been hard at work on the problem at the behest of the film and video industries, which fear widespread piracy in the wake of the growing popularity of DVD-Video and the increasing availability of cheap, high-capacity digital storage devices. DVD will get immediate attention from the new copy-protection technology, as will digital television broadcasting.

The CPTWG has been working on the watermarking project at a stepped-up pace since last summer, when seven promising proposals were winnowed down to three. With Tuesday's announcement, the original goals of the CPTWG's Digital Hiding Sub Group appear to have been met. Among these goals are invisibility in digital-video materials, low gate count for digital-detection circuitry, and easy detection of the watermark in a compressed elementary datastream. Other goals of the group are generational copy control that includes "never-copy," "one-copy," and "no-more-copy" functions; low false-positive detection; reliable detection; the ability to survive normal video processing in consumer use; the ability to be licensed under reasonable terms; and the use of mature technologies for embedding and detecting watermarks. The final system incorporates the best aspects of the three final contenders.