Nine companies gathered here this week to announce the successor to DVD technology, the Blu-ray Disc, a far denser, blue-laser-based medium that is not compatible with its wildly successful ancestor. All nine are also steering committee members of the DVD Forum but have opted to conduct the Blu-ray work outside of the DVD Forum.

Conspicuously absent from the Blu-ray roster is DVD Forum leader and DVD format pioneer Toshiba Corp., which reportedly was invited to join but demurred, asserting that the work should be conducted under the auspices of the forum. With the DVD Forum headed for its annual general meeting at month's end and nine of the 17 steering committee members pursuing Blu-ray, there may be some locking of horns over the forum's future direction. It is possible that the focus could shift to the Blu-ray format by majority vote.

The proposed format uses a blue-violet laser, a 0.1-mm protection layer and a lens with a numerical aperture (NA) of 0.85. Current DVD disks employ a 650-nm red laser, bond 0.6-mm-thick disks and specify a 0.6 NA. Systems based on the Blu-ray format could ship as early as the fall of 2003. Technology licensing is expected to start this spring.

While the format itself is not compatible with DVD technologies, systems could be made compatible in some way, said Pioneer executive corporate engineering adviser Masao Sugimoto. He did not offer specifics.

"This is a technological format; product planning is up to each company," he said.

The 12-cm disk is the same size as its DVD counterpart but has a maximum capacity of 27 Gbytes per side (compared with 4.7 Gbytes for DVD disks) to accommodate high-definition content recording. The format would allow a disk to store more than two hours of HD video content and 13 hours of standard television broadcasts.

The nine companies backing the format are Hitachi, LG Electronics, Matsushita Electric Industrial, Pioneer, Royal Philips Electronics, Samsung Electronics, Sharp, Sony and Thomson Multimedia.

At Optical Data Storage Topical Meeting 2001, held last April in Santa Fe, N.M., all nine companies now backing Blu-ray presented papers detailing a similar technology: a blue-violet laser with a wavelength of around 400 nm; a 0.1-mm protection layer and a lens NA of 0.85.

By last autumn, physical parameters had converged on that set of parameters for next-generation disk systems. Further, all prototypes demonstrated last autumn at CEATEC in Japan by disk system developers such as Sony, Philips, Hitachi, Pioneer and Matsushita were based on those parameters.

Group management committee member Jan Oosterveld of Philips Electronics said that the consumer electronics industry has coalesced around a common format, which will be essential to the Blu-ray Disc's success.

The driving force behind the new density is the emergence of high-definition TV, which has stumbled in the United States but which is slated to debut in terrestrial broadcast systems next year. Blu-ray single-disk recording capacity is defined as 23.3 Gbytes, 25 Gbytes and 27 Gbytes.

A double-layer disk with about a 50-Gbyte capacity that Matsushita and Hitachi demonstrated will also be included in the format within this year. Further variations, such as 30 Gbytes per layer, read-only disks and one-time-recording disks, are also in the works.

In the groove

The format uses only the groove tracks to record data. The track pitch of the 27-Gbyte version, at 0.32 micron, is less than half the 0.74 micron of DVD disks. The minimum mark length is 0.14 micron, down from DVD's 0.4 micron.

The data-transfer rate is 36 Mbits/second — fast enough to record HD content. MPEG-2 transport stream compression is specified to maintain compatibility with global digital broadcast standards. A unique ID for each disk protects copyrights.

The format will be marketed first in Japan and then in the United States and Korea, Pioneer's Sugimoto said.

The DVD Forum, for its part, is not limiting its format standardization efforts to red-laser-based disk systems, a forum spokesman said. Preparatory work on the next-generation DVD follow-on for HD video content has begun, he said.

Technical schisms, of course, are nothing new to the consumer segment. The DVD Forum failed to unify the recording format for standard-definition video recording on DVDs, and both DVD-RAM and DVD-RW continue to have their adherents. Outside of the forum, still other parties have backed DVD+RW.

Forum leader and DVD format originator Toshiba, meanwhile, was asked to join the Blu-ray Disc effort but declined. A Toshiba spokesman said the company wanted the work to proceed under the auspices of the DVD Forum.

Reconcilable differences

For the Sony-Philips camp, Blu-ray constitutes an effort to kick-start its initiative in optical-disk standards, said Reiji Asakura, a high-tech writer and columnist. Before the DVD format coalesced around a 12-cm optical video disk in 1995, Sony and Philips proposed the Multimedia CD (MMCD) format, butting heads with Toshiba, Matsushita, Hitachi and other backers of the Super Density (SD) format. Ultimately, the DVD format was built primarily around the SD proposal but with some amendments contributed by the MMCD camp. Since then, Toshiba has been the flag bearer for DVD format activity.

That dominance "started back in 1994, [when] MMCD lost against SD. Then Sony and Philips lost the RAM recording-format dispute," Asakura said.

Toshiba intends to stick to its guns in calling for open discussions of the next-generation format within the DVD Forum. Toshiba also has its own proposal for a next-generation disk system, which was demonstrated at the Consumer Electronics Show in January. It features capacity of 30 Gbytes per layer using land and groove recording.

None of the Blu-ray proponents has yet made clear its marketing plans for the disk systems. Asakura expects recorders to debut in the fall of 2003. "It will take at least one year for system design, IC design, software and firmware development," he said.