We are witnessing a quiet but dramatic technological revolution in AV. And one of the major players in this revolution is the Digital Versatile Disc, sometimes referred to by its original name: Digital Video Disc.

DVDs can do much more than just play video. This compact-sized digital media format is referred to as a "convergence" medium, because it encompasses both home entertainment and information storage. It is destined to replace the audio CD, laser disc, videotape, CD-ROM, and even video game cartridges. As the only technology to be jointly developed and supported by the major electronics companies, computer companies, and movie and music studios, it is rapidly becoming the most successful consumer electronics product of all time--within only three years of its introduction.

What is a DVD? It looks like a CD, but has seven times the capacity. A DVD can be single-sided or double-sided. Each side has one or two layers of data.

How much can it hold? A single-layer disc typically holds just over two hours of video. However, it's possible to put about eight hours of VHS-quality video or 160 hours of audio on a single-layer. A CD holds about 650 megabytes (0.64 gigabytes). A double-sided, double-layer DVD can hold 17 gigabytes of data.

DVD-Video vs. DVD-ROM--DVD-Video holds video programs and is played in a DVD player hooked up to a TV. DVD-ROM holds computer data and is read by a DVD-ROM drive hooked up to a computer. The difference is similar to the difference between an audio CD and a CD-ROM. Most computers with DVD-ROM drives can also play DVD-Video discs. Since all DVD drives can also read CDs, forecasters expect manufacturers to stop making CD-ROM drives in 2001 or 2002. Anyone buying a computer these days should consider getting one with a DVD drive.

Recordable DVD--Things are not so clear-cut on the recordable front. There are four recordable versions of DVD-ROM. DVD-R holds 4.7 gigabytes and is compatible with many of the existing drives and video players. But it can be "written," or recorded on, only once. The other three can be rewritten a thousand times. DVD-RAM is not compatible with most existing drives and video players, and acts more like a removable hard disc that can also read DVD-ROM discs. DVD-RW and DVD+RW, supported by different manufacturers, will be available by 2001.

Computer Requirements--Most DVD PCs can play DVD movies. In addition to the drive, the computer must have the proper hardware or software to decode MPEG-2 video and Dolby Digital audio. Good quality software-only playback requires at least a 350MHz Pentium II or a Mac G4. Microsoft Windows 98 and 2000 both include DirectShow, which provides standardized support for DVD-Video and MPEG-2 playback. DirectShow can also be installed in Windows 95. Windows NT 4.0 supports DVD-ROM drives for data, but has very little support for playing DVD-Video discs. Macintosh G4s come standard with DVD-ROM or DVD-RAM drives.

DVD and TV--Computers actually have the potential to produce better video than set-top DVD players. This is because of progressive display and higher scan rates. A PC with a good decoder connected to a large VGA monitor can provide picture quality far beyond a standard DVD player and TV.

DVD vs. VHS--Most planners use VHS video to provide training, promote incentive trips, and the like. Since most people don't have a VCR and monitor on their desk, they have to convene somewhere to watch the video. And since VHS is a linear format, you have to fast-forward or rewind to go to specific spots. VHS is also a poor archival medium, as tapes can be degraded during playback and storage. DVD addresses all of these problems. A DVD device can be mounted on a network for distribution from a single point. You can have up to eight audio tracks, so a single DVD can address geographic and cultural barriers by supporting multiple language tracks or subtitles. Multiple video tracks can be embedded on a DVD, allowing diverse audiences to be addressed by a single disc, while ensuring that viewers see only the material that is relevant to them. A DVD is lighter to ship and more durable than videotape. And if all this isn't enough, it's cheaper to produce.

The revolution is at hand!