DVD Formats - Get a clear
(By Mok Heng
Ngee, Computer Times September 18, 2002)
With prices already
below the $1,000 mark, have you considered getting a DVD
burner for your PC? If so, do some research first, because
a DVD created by certain burners may not run on some DVD
Distributing your data or amateur home
videos on DVDs seems like a cool idea, especially since
home DVD players are getting common. A single DVD, or
digital versatile disc, can store between 4.7 GB and
17 GB of data, or seven times more than a 650 MB CD-ROM.
The DVD movies which you buy are encoded
in a format called DVD Video, which can be read by all
home DVD players and PC DVD drives. Some software makers
are also starting to distribute their applications on
a single DVD-ROM instead of multiple CD-ROMs.
While the two read-only DVD formats --
DVD Video and DVD-ROM -- are mature today, there is
a technology war being fought over the DVD recordable
Shop around for a DVD burner and you will
come across models supporting different recording formats:
DVD-RAM, DVD-R, DVD-RW, DVD+R and DVD+RW. And yes, the
plus sign is not a typo mistake.
Check the facts about compatibility before you settle
for a DVD burner or player.
Burners: How they compare:
to commercially distribute movies which can
be played on home DVD players
is 17 GB (if two layers on both sides are
used), huge capacity is big advantage over
CD-ROM as more movie details can be stored.
to store/ distribute data in the same way
CD-ROMs are used.
to DVD Video, but with computer-friendly file
|DVD-R and DVD+R
for storing data or movies. Write-once only;
versions of DVD-R: DVD-R(G) and DVD-R(A).
(DVD+R is relatively new in the market)
for storing data or movies. Rewritable up
to 1,000 times.
only CLV* rotation method; constant bit rate;
native Mac support; may be able to read DVD-RAM
management; supports both CLV and CAV** rotation
methods; variable bit rate; will be supported
by Mount Rainier file system in Windows Longhorn.
as a virtual hard disk/ shared storage on
PCs. Rewritable up to 100,000 times.
random read-write access; capacity is 2.6
GB to 4.7 GB per side.
|* CLV or Constant
Linear Velocity: The disc is read/ write at
a constant speed regardless of which part
of the disc is being accessed.
|** CAV or Constant
Angular Velocity: The disc is read/ write
at different speeds depending on which part
of the disc is being accessed.
From the names, it is obvious that DVD-R
and DVD+R are write-once formats.
Like their CD-R counterparts, DVD-R/+R
discs can only be recorded upon once.
On the other hand, DVD-RW and DVD+RW are
rewritable formats, which support up to 1,000 rewrites.
The fact is that the DVD-R/-RW and DVD+R/+RW
specifications originated from different camps, and
are backed by equally influential industrial bodies.
With members including Hitachi, Matsushita
(Panasonic), Toshiba and Pioneer, the DVD Forum (http://www.dvdforum.org/)
and the Recordable DVD Council are behind the DVD-R/-RW
(and DVD-RAM) specifications.
Supporting the DVD+R/ +RW standards is
the DVD+RW Alliance (http://www.dvdrw.com/) with leading
companies such as Sony, Ricoh, Hewlett-Packard, Philips,
Mitsubishi, Yamaha and Thomson Multimedia under the
If you get a DVD-R/-RW burner, make sure
you get the corresponding DVD-R or DVD-RW discs only.
All five types of recordable media are easily available
in Singapore from $8 (for a 4.7 GB DVD-R) to $39 (for
a 4.7 GB DVD-RAM).
While both standards record to a 4.7 GB
disc, DVD-RW and DVD+RW differ in several aspects. Most
DVD-RW burners provide native Macintosh support and
can also read DVD-RAM discs.
To make matters more complex, the DVD-R
format are sub-categorised into two groups: DVD-R(A),
and DVD-R(G) -- the A and G representing "Authoring"
"General" respectively. The
difference is significant since a DVD-R(A) burner may
not record to a DVD-R(G) disc and vice-versa.
Virtual hard disk
While you may want to burn your home videos
on a DVD-R/-RW or DVD+R/ +RW disc, the DVD-RAM format,
which is also supported by the DVD Forum, is geared
more towards data storage.
Unlike the other media types, DVD-RAM
discs are usually sold in cartridges and feature real
random read-write access. You can rewrite data to a
DVD-RAM disc for up to 100,000 times. On PCs and Macintoshes,
a DVD-RAM drive is very much like a hard drive of a
capacity of between 2.6 GB and 9.4 GB.
Now comes the tricky part: compatibility.
If you are one of those gizmo-geeks who had purchased
your home DVD player when it first appeared in the shops,
the bad news is that it is unlikely that your player
can play movies recorded on DVD-RW/+RW discs, although
most DVD-R/+R discs should work.
On the other hand, the newer DVD players
and DVD-ROM drives should be able to access data and
movies stored on DVD-R/-RW/+R/+RW discs with the exception
of DVD-RAM discs. DVD-RAM discs are really only good
for data back-up and storage.
Most DVD+RW burners will also be able
to write to DVD+R discs. Similarly, most DVD-RW burners
will be able to write to DVD-R discs. And almost all
DVD-R/-RW/+R/+RW burners will be able to read from any
of the recordable media types (except DVD-RAM discs).
Most of these (except DVD-RAM burners) should also be
able to read from and write to CD-R and CD-RW discs.
The above rules only act as a rough guideline;
be sure to ask your dealer about compatibility with
the various DVD recording formats.
So, which standard should you invest your
dollars in if you really want a DVD burner now?
For data back-up or shared network storage,
DVD-RAM is fine, if you ignore the compatibility issues.
For recording home videos, check if the
target DVD player supports your chosen format.
Many have likened the rivalry between
the two DVD recordable camps to the Sony Betamax versus
VHS showdown a couple of decades ago, or the competition
between the Iomega Zip disk and the LS-120 SuperDisk.
Nevertheless, in February this year,
several major electronic makers agreed on greater cooperation
for setting standards when the next generation of blue
laser DVDs appear.