|
||
 |
||
|
| Crossing The Digital Versatile Disc Divide |
 Email This
 Print ThisView My Personal Library |
|
Computing Basics October 2001 • Vol.12 Issue 10 Page(s) 56-59 in print issue |
Crossing The Digital Versatile Disc Divide What You Need To Know About Competing DVD Formats | ||
 The many competing DVD (digital versatile disc) formats and specifications might make purchasing seem like a difficult process, but manufacturers are working hard to prevent confusion about disc and drive incompatibilities. This month we'll discuss these differences so you can do your DVD shopping with peace of mind. Scott Mueller, president of Mueller Technical Research and author of "Upgrading and Repairing PCs," offers this description of DVD: "From a technical point of view, DVDs are the same as CDs. The big thing about DVD is that the track is about four times denser than a CD. Combining this greater density with improved encoding schemes, we end up with much greater capacity."  Something Old, Something New Six types of DVD drives are currently available (not counting the still-mysterious DVD+R format). Most consumers are aware of the increasingly popular DVD-Video (for home DVD players) and DVD-ROM formats, but four newer formats go beyond simple movie playback or data access to let users record information and media to DVDs as well. These formats include DVD-R (DVD-recordable), DVD-RAM, DVD-RW (DVD-rewriteable), and the latest, DVD+RW (DVD +rewriteable). The emergence of the DVD+RW format has prompted industry people to refer to DVD-RW as "DVD minus RW." Although it hasn't hit the market as of press time, early support from Dell, its No. 1 PC manufacturer, should help it make a considerable splash when it arrives. DVD-Video. DVD-Video players read CD-ROMs, DVD-Video discs, DVD-Rs, DVD-RWs, and will also be able to read DVD+RW media. Certain players equipped with the MultiRead and MultiPlay technologies established by OSTA (the Optical Storage Technology Association) can also read CD-R (CD-recordable), CD-RW (CD-rewriteable), and DVD-RAM media, but can't read DVD-ROMs. Several media subformats for movies fall under the DVD-Video format and primarily pertain to a disc's capacity. They include single-layer, single-sided discs; single-layer, double-sided discs; double-layer, single-sided discs; and double-layer, double-sided discs. These formats include nearly all the discs you rent or buy at your local video store, and each corresponds to an industry specification, such as DVD-5 or DVD-10. DVD-5, for example, is a 4.7GB read-only, single-layer, and single-sided disc (the other side usually has a label on it). Another format, DVD-10, is somewhat like two DVD-5 discs glued back to back with no label that offers 9.4GB of capacity. DVD-9, or single-side, dual-layer discs, offer 8.5GB of capacity, but don't require you to turn them over. Instead, your player's laser refocuses at a different depth to access additional content. DVD-9 discs (which compose most of the newer movie releases coming out now) are usually gold instead of silver, which makes them easy to recognize. Finally, the DVD-18 format is a double-sided DVD-9 disc with a 17GB capacity. Users can't write to any of these formats or copy DVD movies to a recordable DVD disc as they are copy-protected. DVD-ROM. Standard DVD-ROM drives can read any of the formats listed above except DVD-RAM. Drives equipped with MultiRead/MultiPlay technology can read that format as well. You can purchase software products on DVD-ROM, and DVD-ROM drives can also read DVD-Video media. Movie playback, however, requires a special software application, such as InterVideo's WinDVD. This is because DVD-Video media store movies using MPEG-2 (Moving Pictures Experts Group) compression. In order to read such formats as CD-R and CD-RW, DVD-ROM drive manufacturers have to incorporate a special component called a dual-laser pickup. "Even though [DVD-ROM drives] use a different wavelength laser than those used to read CD-ROMs, the way the disc is stamped makes a DVD drive capable of reading it," says Mueller. "However, that's not the case with CD-R or CD-RW discs." Mueller explains that the CD-R and CD-RW formats record data differently on the surface of the disc than standard CDs or DVDs. Without dual-laser pickups, DVD-ROM drives wouldn't be able to read such formats. DVD-R. DVD-R, like the CD-R format, only lets users write to each disc one time. Other than its ability to record information, however, a DVD-R drive works much the same way a DVD-ROM drive does. DVD-R drives can read CD-ROM, DVD-Video, DVD-ROM, and DVD+RW media. They can read and write to CD-R, CD-RW, and DVD-R media, even though they aren't compatible with DVD-RAM.
DVD-R's wide compatibility is no accident; the DVD Forum (http://www.dvdforum.org), the standard-setting body for the DVDformat, built it that way. Mike Evangelist, Apple Computer's senior product line manager for DVD products, agrees that compatibility is key. "When we started doing our research on this sort of product two or three years back, it was very clear that the number one consideration of the customer is compatibility," he says. DVD-RAM. DVD-RAM drives can read all formats, but can write only to DVD-RAM media. Stephan Buehler, Vivastar's director of channel development for Europe, says, "DVD-RAM can be rewritten 100,000 times, and is a nice solution for backup because it writes data in a spiral, like a hard drive." Unfortunately, he says, this same feature makes DVD-RAM unable to write to DVD-Video or DVD Audio formats. Bob DeMoulin, product marketing manager for Sony's Value Added Project Division, says the design of DVD-RAM media is a further impediment to cross-platform compatibility. DVD-RAM discs are encased in caddies, which precludes their use with DVD-Video players or standard DVD-ROM drives. DVD-RW and DVD+RW. DVD-RW and DVD+RW drives, like CD-RW drives, are useful because users can erase data and rewrite a single disc many times. DVD-RW drives can read all formats except DVD-RAM, and can write to CD-R, CD-RW, DVD-R, and DVD-RW media. DVD+RW drives, which should become available this fall, can read all formats and write to CD-R, CD-RW, and DVD+RW. They can write data in a continuous stream, which is useful for storing content from TV or other video sources on the fly, much the way a VCR does. "The +RW format also has built-in defect management, so it's really designed to be formatted and used as a computer disk," says Mueller. "You'll be able to drag and drop files to it seamlessly; it will basically act like a 4.7GB hard drive." Mueller favors the +RW format over –RW for several reasons: "The +RW format seems to have the most features, the most backward compatibility with existing drives, and the most forward universal capability," he says. Mueller also cites support from major companies such as Phillips and Sony, which have been instrumental in developing current CD and DVD standards as another major selling point. DVD+R. Although it hasn't gotten much press, yet another recordable DVD format, DVD+R, is in the wings. However, some debate still exists as to whether it will include drives and discs or just non-rewriteable media for DVD+RW drives. Format Showdown "We're kind of in a Beta-max vs. VHS war, especially when we're talking about the rewriteable formats: DVD-RAM, DVD-RW, and DVD+ RW," Mueller says. He says consumers are as confused about competing DVD formats as they initially were about recordable CD formats. "A lot of new CD players are [touting] their compatibility with recordable CD media. I think you can look at the whole recordable CD history as a pretty close parallel to what's happening with DVD." Fortunately, industry experts also think it won't take long to shed some of the confusion. For one thing, DVD products are likely to reach a level of compatibility and customer satisfaction similar to that of current recordable CD products very quickly. Vivastar's Buehler says, "If you compare CD with DVD, it has taken CD years to get the first OEMs [original equipment manufacturers] to integrate the product. But now, OEMs like Compaq, Dell, NEC, Apple, and others are coming out with this product already and selling it as part of a ‘video PC.' And the [DVD] ramp will get up much, much quicker than on the CD." As OEMs adopt recordable DVD technologies, it is likely one or two will quickly emerge as clear front-runners, which should take the guesswork out of buying into this market. Apple's Mike Evangelist says, "We all generally believe that one of these formats will emerge as the dominant one. That doesn't mean that the other types of formats will go away, but it may mean that the other sorts of drives will have to support both types of media, for example." Evangelist echoes Mueller's statement that many new CD players make a point of advertising their compatibility with recordable CD media, and that the DVD market will likely follow the same path. One way to sort out the confusion in the meantime is to carefully inspect the packaging of various DVD products where you shop for electronics. Several formats are currently out there, but packaging for both the hardware and media should nearly always be clearly marked with compatibility information. "It doesn't matter which manufacturer you see on the cover of a product," Buehler says. "If you see DVD-R, it's a [standard] capacity. The same goes for DVD-RW or +RW or RAM. [DVD-RAM] is even easier, because the media for all the current-generation drives in the market are inside fixed covers." Safe Bets For highest compatibility with the best-established formats, DVD-R drives (or better yet, DVD-R combo drives that offer compatibility with more than one format) are your best bets in the current market. Sony's Bob Demoulin says, "A DVD-R/DVD-RW combo would be the safest bet for compatibility to read, write and record DVD-Rs, DVD-RWs, CD-Rs, and CD-RWs." However, if you prefer to play it closer to the vest and let the market sort itself out, you probably won't have to wait long.  by David Geer View the graphics that accompany this article. (NOTE: These pages are PDF (Portable Document Format) files. You will need Adobe Acrobat to view these pages. Download Adobe Acrobat Reader)
|
|
Home Copyright & Legal Information Privacy Policy Site Map Contact Us