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Fifteen Flavors of DVD

by Dana Parker

'Complex problems have simple, easy-to-understand wrong answers.'


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 other drives.

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 DVD-Audio players.

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 (danapark@ix.netcom.com) 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 & Expo.

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