'Complex problems have simple, easy-to-understand wrong
May 12, 2020 | Keeping track of standards in the
optical disc industry is something that only appeals to
a certain kind of person--the same type of person, I would
imagine, who enjoys memorizing and categorizing the details
of pre-Columbian pottery, the genera of dinosaurs, or the
spectral signatures of exoplanets. In the CD world, all
the obscure variations on the red, yellow, green, white,
orange, and blue books are sufficient to sate any pedant,
even as they frustrate and bore the layman.
DVD was supposed to change all that. The idea, often expressed
in the early development stages of the DVD format family,
was to correct or avoid the "mistakes" of CD. While this
might be good news for the casual users of DVD, and for
developers, it didn't bode well for the lovers of arcana
or for standards columnists. The more complex and nonsensical
it gets, the better I like it. If DVD had in fact turned
out to make understanding optical disc formats easy, I'd
have been forced to turn to writing about something slightly
more inscrutable, like, say, the human genome.
As it turns out, I needn't have worried. Today, slightly
more than three years after DVD-Video's first appearance
in the market, there are--count 'em, folks--no fewer than
fifteen DVD-based formats. I couldn't be happier; I just
love explaining the DVD formats to my clients, especially
when I can give them the forewarning, "OK, now the first
thing you have to do is let go of the notion that any of
this is going to make sense."
The read-only group is comprised of DVD-ROM, DVD-Video,
DVD-Audio and SACD. SACD (Super Audio CD, by Sony and Philips)
is included even though it is not a DVD Forum-approved format,
because it is at least based on the physical format of DVD.
As disc formats go, this small group looks simple and well-defined,
but appearances are deceiving. By definition, any DVD title
containing elements that only work on a PC--such as games
or Web connections--is a DVD-ROM, even if it is sold as
a DVD-Video movie. All DVD-Videos, in fact, are a subset
of DVD-ROM, but as new platforms and intelligent set-tops
appear, we can count on no end of variations on this theme--for
example, PlayStation DVD games. I have great expectations
for this category to keep me supplied with column fodder
for years to come.
Once there was one write-once option, and soon there will
be three, possibly four. DVD-R version 1.0 is the 3.95 billion
byte media that is wavelength-specific for 635nm lasers.
For version 2, 4.7 billion byte DVD-R will be split into
two, possibly three, mutually incompatible parts. First,
there is DVD-R version 2 General, which will use a 650nm
laser and media specific to that wavelength. Second, there
is DVD-R version 2 Authoring, with a 635nm laser and media.
Third, the DVD Forum is considering adding a third variation
on version 2.0 DVD-R, tentatively called DVD-R Special Authoring,
which would be developed in conjunction with the MPAA, include
CSS capability, and which might have to be restricted to
licensed users. None of the media manufactured to one of
these DVD-R variations will be recordable on the other recorders,
but all of them, once recorded, should be readable in existing
readers and players.
The controversial DVD-RAM, DVD-RW, and DVD+RW group is
my favorite, because it is so controversial and little understood.
Again, DVD+RW is included because even though it is not
an official DVD Forum-approved format, it is based on the
physical DVD format. In fact, it's far more similar to pressed
DVD than the DVD Forum-blessed DVD-RAM, which bears little
resemblance at all to the read-only version other than form
factor. There are two versions of DVD-RAM, 2.6 billion byte,
and--real soon now--4.7 billion byte.
There is one version of DVD-RW, starting out at 4.7 billion
bytes capacity and currently available in a consumer version,
only in Japan, for $2,500. In addition, there will be one
DVD+RW, version 2.0, at 4.7 billion bytes when it appears
in (projected) early 2001. Even though each of these types
of rewritable media will use non-wavelength-specific phase-change
media, none of the media will be rewritable on any of the
Finally, there are the DVD Recording Application Formats:
DVD-VR, DVD-SR, and DVD-AR. These are specifications for
recording non-digital video, streaming, digitized video,
and audio, respectively, and they "sit on" the physical
formats of the writable DVDs as application layers. Naturally,
none is compatible with existing DVD-Video or forthcoming
Well, maybe not finally, after all--because there's no
indication that the format creation and innovation process
for DVD-based media is slowing down. There's even a possibility
that the DVD Forum will create a program to ensure interoperability
in DVD players and drives for all the members of the official
Forum-approved DVD format family, which is a great idea.
I wish I'd thought of it.
In any case, I'm not concerned anymore that DVD will become
so simple and easy to understand that I will be forced to
turn to classifying macromolecules. Even if the DVD formats
get no more complex than they are today--which is not likely--I'm
reasonably sure the next optical technology to come along
will turn out to be just as much fun.
Dana J. Parker (firstname.lastname@example.org)
is a Denver, Colorado-based independent consultant and writer
and regular columnist for Standard Deviations. She is also
a contributing editor for EMedia Magazine, co-author of
CD-ROM Professional's CD-Recordable Handbook (Pemberton
Press, 1996), and chair of Online Inc.'s DVD Pro Conference
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