The Biggest Disc Ever: Is DVD All It's Hyped To Be?

by Loren Alldrin
Winter 1997

Don't look now, but a there's a new disc technology poised to explode on the consumer electronics scene that could fundamentally change the way we use our computers, televisions, CD players and VHS recorders.

DVD, or "digital versatile disc" as it's now commonly called, is a data storage and playback system that stands ready to revolutionize home electronics.

Still in its formative stages, DVD faces the usual issues central to the widespread adoption of a new technology: cost, availability, utility, ease of use, consumer demand and industry support.

DVD is different from other young technology we've watched develop because "DVD" actually encompasses two completely different systems--one computer-based, called DVD-ROM, and one television-based, called DVD-video.

This distinction tends to be blurred by manufacturer and media hype, which, if you listen to it, has DVD poised to replace the ubiquitous VHS VCR, the audio CD player and the computer CD-ROM drive--just for starters.

It's still young and expensive enough that it could fizzle, but if its catches on, then the shiny DVD certainly has the potential to ultimately change the way you watch, program and interact with your TV, and with the way your computer and TV interact with each other. At its core, the technology is exciting and fundamentally sound.

Tomorrow's TV sets, for example, could have DVD drives and related hardware built right in, all controlled from a remote pointer and keyboard and wired as part of complete DVD-based home theater system that would replace the VCR and audio CD player.

But there are significant hurdles to clear before that will happen, and before we get too far into the future, let's look at today's DVD technology and some of the issues surrounding it.

A Big Bit Bucket

Though it looks identical to a standard CD-ROM, a DVD disc will hold roughly seven times the data of its predecessor--4.7 gigabytes (GB), to be exact. In the future, manufacturers estimate they will be able to make DVD discs with two layers of data on one side (total storage: 8.5 GB), single layers on both sides (9.4 GB) and two layers on both sides (17 GB). All these figures translate to an unprecedented amount of storage capacity for digital video, digital audio, data, graphics, text and more.

DVD consists of two distinct sub-formats, each specifying a different way of allocating the same storage space. The most "rigid" (and most universally compatible) of the two is DVD-video. DVD-video calls for a specific type of compressed video (MPEG-2) and compressed audio in one of two formats, including the high-end Dolby AC-3.

To these, DVD-video can add graphics, multiple language tracks, parental control and basic branching. The branching routines give the format some rudimentary interactive capabilities, but DVD-video's main application is in the linear playback of pre-recorded movies.

DVD-ROM, the second DVD sub-format, is more truly "versatile." Like any computer storage medium (CD-ROM, for example), DVD-ROM is simply a "bit bucket" to store data. Manufacturers can pack DVD-ROM with any kind of information, including digital audio and video in any format. A DVD-ROM disc can hold the same exact video and audio information as its DVD-video brethren; the key is it doesn't have to.

Separate Worlds

These two types of DVD data have two distinct target applications. DVD-video is the format that manufacturers hope will replace your VCR as the way you watch pre-recorded movies. Set-top DVD-video players cost less than $500 today, and many predict prices may fall as low as $250 in coming years. Still, DVD players won't completely replace VCRs until they are made capable of recording. Over the next two years, if the industry grows to its potential, expect the introduction of a recordable format. When the price of this machine compares to that of a VCR, sing a dirge for the latter.

DVD-ROM, by nature of its open-ended file system, is a direct hit for the distribution of computer software. CD-ROM developers are already porting their multi-disc behemoths onto a single DVD, and many are adding enhanced capabilities in the process. Expect to see the most dramatic improvement with DVD titles in video and audio. Where CD-ROM developers often had to squeeze jumpy video into small windows, DVD-ROM titles can flaunt full-screen, full-motion video and better-than-CD sound. When you factor in the ability to supplement video and audio with any other type of data, the increased flexibility of the DVD-ROM format is clear.

What's not so clear, at first glance, is where these two related formats cross paths. Can a computer DVD-ROM drive play back a movie from a DVD-video disc? Can a set-top DVD-video player access DVD-ROM data? Many interactive multimedia publishers are dealing with this question by creating dual-format DVD titles playable on either computer DVD-ROM or consumer DVD-video players.

A survey earlier this year of 56 consumer multimedia manufacturers by Infotech, a Vermont-based research organization, revealed that 23 percent of more than 80 DVD-ROM titles that were in development will be cross-compatible with DVD-video players.

A cross-compatible DVD disc plays on either type of player, either video or ROM, but the DVD-ROM version has the capability to offer more extensive interactivity and richer sound and graphics.

How truly interactive this "new" dual format will be on the TV, how much it will cost and how it will be labeled for consumers remains to be seen, but buyers should beware of placing too much stock in these claims of "duality" during these early stages of the game, while all the marketing and technology kinks get worked out.

Swap Meet

But chances are there will eventually be a satisfactory conclusion to these outstanding issues, and to understand the implications of swapping discs between computers and set-top players, it's helpful to explore what each format does with data once it's read off DVD disc.

In the case of a DVD-video player, the processing is rather simple. After audio and video data come off the drive, they go to dedicated processors for decompression and conversion to analog. The end result is a composite, S-video or component video signal, and stereo or surround audio.

In response to user commands, the DVD-video player will also access up to eight different foreign language soundtracks, 32 subtitle streams, and up to nine different camera angles for a given scene, if they are available. The DVD player will allow users to select from different movie formats (i.e. 16x9, letterbox or pan-and-scan) or ratings (G, PG, PG13) on the same disc if included. Finally, the DVD player will allow users to pilot through different endings or alternate story lines when available. As a video playback device, the DVD-video player is smarter than a satellite receiver and Laserdisc player put together. As for computer-style processing, the DVD-video player doesn't hold a candle to a Sony Playstation.

In comparison, a DVD-ROM player is feeding data to a full-fledged computer. This computer may include dedicated 3D graphics processors, a sound card or synthesizer and multimedia capabilities galore. Because of the computer's power, the potential for intellectual richness and depth in a DVD-ROM title can't be beat. Whereas a DVD-video unit is primarily a playback device, a computer with a DVD-ROM drive is a processing device.

Which brings us back to the topic of interchangeability between DVD-video and DVD-ROM. In the same way it's easier to make a computer act like a TV than vice-versa, it's much simpler to equip a computer to read DVD-video discs than a DVD-player to read (and process) DVD-ROM.

To view a letterboxed DVD-video version of Legends of the Fall on your computer, you need only equip your computer with MPEG-2 and audio decompression capabilities. Currently, the best way to do this is in hardware, though developers are working to decompress MPEG-2 in software on Intel's new MMX processor. Plug in a card or two, and your computer will operate just like a set-top DVD-video player. If you don't want to upgrade your current computer, you don't have to. Gateway 2000's Destination "big screen" PC/TV comes standard with a DVD-ROM reader and decompression hardware, making it able to play both DVD-video movies and DVD-ROM titles. Other computer and convergence product manufacturers are following suit.

Unfortunately, going the other direction isn't so easy. Bringing a DVD-ROM title to life on the living room television would require a full-fledged computer to handle all the processing chores. A DVD-video player would need a CPU (central processing unit), graphics chips, RAM, a sound card and dozens of other subsystems to boot up a fully interactive DVD-ROM program. While at press time none actually existed, industry officials say that interactive "movies" like Tsunami's Silent Steel are being outfitted to work with a DVD-video player's story-line branching capabilities.

According to a Tsunami Media statement, "The intricate, branching story line …is perfectly suited for set-top DVD-video players, and the video and software engine that drives the PC version would require little change for a TV version,"

This approach would work equally well other relatively simple story-line based adventure games, where during the course of the "movie," a player would make decisions that would affect the outcome of the plot, but applications with a higher degree of sophistication are beyond the capabilities of the DVD-video player. A basic DVD player, for example, can't render the real-time 3D graphics required for a flight simulator or first-person shoot-em-up.

A Matter of Time

DVD-ROM will inevitably grow as a computer-based storage medium for the simple reasons the discs hold more data and the drivers play them back faster. Because the players are backward compatible with CD-ROMs, as the cost comes down, gamers and other disc-heads will lead the widespread adoption of the next generation of disc-based technology.

Issues surrounding the DVD-video format are more complicated and are reminiscent of the VHS-Betamax format wars. Early in 1997, a forum of manufacturers had supposedly agreed on a standard format for manufacturing DVD discs. That was before at least three of the manufacturers apparently reneged and announced they would launch a format of their own that was significantly different from the forum standard. As of press time, there was no resolution to this situation. We've seen competing formats hurt a fledgling technology before in the case of the VCR, and the future of DVD largely rests on what happens on this front.

Without an industry standard, the competition this affords, and the lower prices this creates, consumers will most likely be unwilling to support the new technology in numbers sufficient to drive its growth. Without consumer support, movie industry executives, who have so far been tentatively supportive of the new technology, will decline to adopt it wholeheartedly. Without lots of new movie titles migrating to the new format, it will fail to meet the consumer demand now filled by VHS. DVD could either revolutionize the way we watch TV, or fade into the obscurity of unfulfilled potential.

Loren Alldrin is a technology consultant and freelance writer.