Recently, there have been a number of exciting developments in digital versatile disc (DVD) technology. Just a year ago, recording to DVD was a big-budget affair. Today, however, DVD-Recordable (DVD-R) drives and media are hitting the streets at applications.
The benefits of using DVD technology in the personal studio are substantial. However, so that they can make intelligent decisions when mastering their music in this medium, it is important for musicians to learn about the various physical and application formats that come under the guise of DVD.
What are the differences between the various DVD formats? What can you do with a DVD that can't be done with CD? Let's take a look.
Part One: Dissecting DVD
Like CDs, DVDs originally entered the marketplace as a nonrecordable format. However, unlike the development of the CD-Recordable format, which occurred a number of years after CDs were introduced, the first DVD-Recordable drives and media appeared within a few months of the release of DVD. DVD-R was created in part to meet the demands of content producers who needed a reasonable way to proof their releases.
The first drive to hit the market, the Pioneer S-101, was priced at $17,000. Although the price was steep, DVD producers quickly found that they couldn't live without this tool.
Recordable DVD technology got a giant boost in 1999 with the release of the Pioneer S-201 ($5,400). At less than a third of the price of the S-101, the S-201 opened DVD-R to a broader market. At the same time, inexpensive yet incompatible DVD-RAM drives and media became available. In January 2001, Pioneer announced the release of the Pioneer A03, a so-called Super Drive that handles write-once and write-many DVD formats as well as CD-R and CD-RW. Pioneer believes that it will be able to price the A03 substantially less than $1,000.
Other manufacturers (notably Panasonic) have now entered the market, and Compaq and Apple are bundling DVD-R drives with their products. Component drives priced less than $1,000 for existing computers were expected to hit the stores in June. By the time you read this, recordable DVD will be a reality for mainstream consumers, with multiple offerings available from a growing list of vendors.
DVD has three primary uses: in desktop applications as a giant “bit bucket” for data storage; in consumer-player applications using the standard consumer DVD formats; and in hybrid applications that can combine standard DVD features with special functions, such as Web linking, that are available only when the DVD is played on a computer.
Standard and hybrid DVD applications offer five basic benefits over compact discs: DVD audio quality surpasses the audio quality of a normal CD; DVDs are able to store discrete, multichannel surround sound and high-quality video; DVDs offer much longer playing times than do CDs; and PC-based interactivity can be authored into a DVD. Although you can combine these features, there are limits to the ways that video images, high-density audio, and surround sound can be used together. For example, with the DVD-Video format, multichannel surround audio is only available in a data-compressed form when it accompanies video content. If you want your audio uncompressed, you are permitted only two channels.
A Ball Of Confusion
You will need a little more than the usual knowledge and ingenuity to tap the DVD-R's full potential while staying within your budget. To begin with, there are a number of different formats to work with, and there are incompatible variants within the most prevalent format as well. Incompatibilities linger between the recordable media and some players on the market, which affects the range of practical applications.
In addition, there are multiple DVD applications for musicians to consider. The great majority of players play the DVD-Video format only. However, DVD-Audio offers important advantages for musicians.
Finally, although there are a number of affordable tools for preparing and mastering DVD-compatible content, such products tend to be biased toward video and often do not support the full range of DVD's audio capabilities. To use the current crop of DVD authoring tools solely for audio applications requires special knowledge and careful attention. Depending on your requirements, the costs of the tools can vary greatly.
Recordable Or Replicated
In order for DVD to become a commercially viable format, two technological hurdles needed to be overcome. Disc manufacturers needed to be able to consistently meet the necessary tolerances in pit size and track pitch (which is the distance from one data track to another) in order to put several times more data on a DVD than they were able to put on a CD. The second requirement was a laser element that could read those much finer pits. The size of the pit that can be read by an optical drive (CD or DVD) depends on the wavelength (or color) of the light emitted by the pickup head. The lasers required for DVD, which read shorter wavelengths, became available in the late 1990s.
For both CDs and DVDs, there are fundamental differences between a manufactured disc and the recordable medium. Up to this point, I've been referring to pits on the disc. In reality, the data on an optical disc can be represented in several ways. The player's laser-pickup head includes a light-emitting laser diode and a separate photo diode that responds to light and dark. The laser diode focuses its beam of light at the target. The photo diode sees the return signal as either light or dark. In manufactured CDs and DVDs, data is represented by pits that scatter the light or lands that reflect it straight back to the pickup head.
In recordable DVD and CD technology, there are no pits. Light and dark states are produced by a photosensitive dye or a metal alloy, the reflectiveness of which changes in response to the writing laser.
Because DVD players are designed principally to play commercially mass-produced discs, there is no guarantee that the laser pickups on a given player will match the reflective characteristics of today's DVD-R discs. That is especially true with older DVD players.
Replicated DVDs also have a technology element not present in CD: the ability to put data on separate layers. Both data layers of a DVD disc are transparent, and both have a reflective layer behind them. The drive's laser-pickup head focuses on one layer or the other. That ability is similar to the way you can look out a window on a rainy day and selectively focus on the raindrops or on the landscape beyond. However, with DVD-R, in which the medium is opaque by nature, there is only a single layer. This is an excerpt from the following article: DVD-R: A World of Options.
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