Multiple DVD rewritable formats ready to roll
By Yoshiko Hara
EE Times
(11/03/98, 3:48 p.m. EDT)
TOKYO — Consumers may soon be picking their
way through a minefield of competing rewritable
disk formats, wondering which of the
12-cm-diameter platters is compatible with their
DVD recorders.
Though the DVD-RAM disk with 2.6-Gbyte
capacity is at present the only rewritable disk that
packs more than a Gbyte, several formats are
ready to step up to bat between now and early
next year. They include the DVD-R/W,
promulgated by Pioneer, and the
second-generation DVD-RAM, both at 4.7-Gbyte
capacity; NEC's 5.2-Gbyte Multimedia Video File
disk system; and the 3-Gbyte DVD+RW from
Sony and Philips.
Pioneer Electronic Corp., the first to demonstrate a
different format, has leveraged its DVD-R
technology to develop a prototype DVD-R/W disk
system with a 4.7-Gbyte capacity. "DVD-R/W
aims at VCR replacement," said a Pioneer
spokesman.
Standard status?
Pioneer took the lead in establishing DVD-R as a
standard format at the DVD Forum, and now the
forum is considering whether DVD-R/W should
also become one of the DVD-family formats.
Though Pioneer expects that its physical format will
be established as version 1.0 next spring,
observers believe the scheme may not be ready for
prime time.
"Even if DVD-R/W is established in terms of
technology, it may take time before it becomes
version 1.0, the level ready for commercialization,
because of political reasons," said a spokesman for
the DVD Forum. Among the stumbling blocks are
copy protection and compatibility issues.
Meanwhile, the DVD Forum has been hammering
out the second-generation DVD-RAM, with a
capacity of 4.7 Gbytes, and expects to publish the
specification before the end of the year.
DVD-RAM — both the first and second
generation — is positioned as a peripheral drive for
personal computers. However, Hitachi and
Matsushita, the main DVD-RAM developers, have
already shown prototypes of video servers and
video-disk cameras that assume the
second-generation DVD-RAM disk system. These
companies do not deny the possibility of using the
4.7-Gbyte RAM for consumer applications.
"If both DVD-RAM and DVD-R/W are
introduced to the consumer market, how will we
position them in the market? The forum has not
reached accordance," said the DVD Forum
spokesman.
Hot potato
Copy protection is a hot potato in this market. The
4.7-Gbyte RAM will take over the same
PC-linked copy-protection measure that was used
for the 2.6-Gbyte version. But if DVD-R/W aims
at audio/video applications, it too must incorporate
a copyright scheme. Copy-protection
specifications have not been nailed down, and that
makes announcement of version 1.0 within this
year uncertain.
"It needed so much time [to work out specs] for
even a ROM disk. For recordable formats, it is
difficult to foresee how long it will take to settle the
copyright issue," said the forum spokesman.
Yet another problem facing DVD-R/W is
compatibility. A DVD-R disk is fully compatible
with ROM drives, and DVD-R/W must be, too.
Theoretically, ROM drives and ROM players
should be able to read the disk as it is. But in
reality, existing DVD video players cannot read
DVD-R/W disks because of differences in the
video format.
"We are developing a format suitable to
DVD-R/W," said the Pioneer spokesman.
NEC Corp. is another company that will propose a
proprietary rewritable format. Early next year,
NEC will begin shipping a sample of the 5.2-Gbyte
Multimedia Video File (MMVF) disk system.
NEC developed the original version of this format
in 1996 and has been fostering the disk system as
MMVF.
"NEC has already shifted MMVF from a
laboratory project to a business project," said an
NEC spokesman.
MMVF's specifications resemble those for DVD
disks. It employs a 12-cm diameter disk with two
0.6-mm-thick phase-change disks bonded, a
640-nm laser and land-and-groove track
recording. NEC claimed that the 5.2-Gbyte density
was achieved mainly by the development of new
PRML (partial response, maximum likelihood)
signal-processing technology, which makes it
possible to record in narrower-pitch tracks.
NEC plans to ship a bare-drive sample to set
manufacturers, including its internal
set-manufacturing section. "Some set
manufacturers may build a video recorder using the
drive as the core," said the NEC spokesman. "We
are participating in discussions at the DVD Forum
and may be involved in future format making, but at
present, NEC will concentrate on MMVF
promotion."
Sony and Philips, meanwhile, are promoting
DVD+RW, a 3-Gbyte system. Originally set to
debut this fall, DVD+RW has been delayed; Sony
now plans to begin shipments next spring.
For now, Sony positions the DVD+RW as a PC
peripheral. But in competition with DVD-RAM,
Sony and Philips are considering increasing the
capacity to 4.7 Gbytes and spinning it for
consumer gear.
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