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DVD: An Introduction for Health Sciences Librarians Brian D. Cameron MA, MLS Information Specialist, Health Sciences Libraries The Toronto Hospital 585 University Avenue, BW 9-601 Toronto, Ontario M5G 2C4 tel: (416) 340-4800, ext 3022 ; fax: (416) 340-4384 e-mail:
[email protected]
CD-ROM is now being displaced by DVD, a new data storage system offering tremendous advantages over CD-ROM. Recent predictions suggest that by the year 2001, DVD will overtake CD-ROM in the optical computer disc market. It will also replace VHS, laserdisc, and audio and video CD formats. Librarians will need to know how DVD differs from CD-ROM, what benefits DVD offers, what we can expect from this new medium, and what the future holds for optical disc storage.
What is DVD? In September 1995, ten years after the launch of CD-ROM and thirteen years after the launch of audio CD, the two competing consortiums developing high-density storage systems— the Toshiba/Warner group and the Philips/Sony group— agreed to compromise on their high-density disc specifications and support a unified format that would satisfy both the movie industry and computer applications developers. DVD, the resulting format, was launched in Japan in November 1996. Table 1 outlines the five format configurations designed by the DVD Forum. (In order to express its applicability to more than video, DVD, formerly known as Digital Video Disc, was changed to Digital Versatile Disc. Now, DVD has been reduced to an acronym that stands for itself). Table 1 - DVD Formats Format Mode DVD-Video playback only
Applications movies, audio/visual media
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DVD is high-capacity optical disc technology, on the surface not unlike CD-ROM. Both polycarbonate discs are 12 cm in diameter, weigh 25.57 grams, are 1.2 mm thick, but, unlike CD-ROM, DVD is comprised of two bonded 0.6 mm discs. The bonding of two discs creates a more rigid substrate than CD. More importantly, it produces a disc with two distinct, readable sides. A double-sided disc, created from two discrete thinner discs, allows for increased pit density and narrower tracks, resulting in higher data density— as much as 17 billion bytes. CD-ROM can comfortably hold 650 MB of data, or approximately 74 minutes of digital audio. As indicated in Table 2, a DVD disc can accommodate 4.7 GB (or 2 hours of MPEG-2 video) and, eventually, 17 GB (or almost 8 hours of video).
Table 2 - DVD-ROM and DVD-Video Format and Capacity Format Configuration Capacity Video (approx.) DVD-5 Single-Sided/Single-Layered 4.7 GB 2 hours DVD-9 Single-Sided/Dual-Layered 8.5 GB 4 hours DVD-10 Double-Sided/Single-Layered 9.4 GB 4.5 hours DVD-18 Double-Sided/Dual-Layered 17 GB 8 hours
Double-sided discs will have to be flipped or used in drives capable of reading both sides. Currently, most DVD-ROM and DVD-Video discs follow DVD-5 specifications.
The DVD Advantage DVD offers many advantages: the ability to accommodate a full-length feature film (approximately 135 minutes), increased picture quality (based on higher compression ratios of MPEG-2 video), audio compatibility with matrixed surround (DTS and Dolby AC-3 audiostream), 5.1 position channels offering better fidelity and complete channel separation, multiple aspect ratios, non-linear access, the ability to accommodate three to five languages and multiple versions of the same program on one disc, copy protection, a parental lock-out feature, backwards compatibility with CD-ROM, and interactivity. Many of
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CD had been invented. Unlike CD-ROM, DVD is designed to be computer-compatible because it utilizes the Universal File System. The result is faster data transfer. Even though CD was not designed for computer applications, CD-ROM databases matured into a very sophisticated medium. And, the multimedia industry adopted CD-ROM once its value had been demonstrated in libraries. Because DVD has been designed with both the home entertainment and computer industries in mind, databases and other applications on DVD will be quantitatively and qualitatively different, especially once DVD’s potential is fully recognized by developers.
DVD in libraries Currently, we are in the third stage of DVD development, with some DVD drive manufacturers shipping second and third generation products. In the near future, DVD will become a more economical product than CD-ROM. The number of titles will continue to grow, and DVD drives will decrease in price and become a standard peripheral on most PCs. While the decision to upgrade to DVD may not be clear cut for every library (1), once performance and reliability are established and compatibility issues are completely resolved, DVD will be adopted by many libraries. (2)
Librarians and information professionals will appreciate the advantages of DVD’s increased data storage and faster data transfer. At its maximum capacity, DVD can store the content of 25 to 30 CDROMs. An obvious benefit of higher-capacity discs is that they provide the ability to search greater spans of years, larger data sets, or multiple databases without changing discs or re-executing search strategies. As an example, early DVD databases included phone directories, otherwise spread over several CD-ROMs.
The first ‘build database’on DVD, The Union Catalogue of Belgian Research Libraries, took
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commitment to utilizing DVD technology, and it ensures that advancements will continue to be made in database design.
With improved multimedia capabilities, DVD represents a significant revolution in both database design and searching capabilities. Large amounts of video cannot be included on CD-ROM because CDvideo (utilizing MPEG-1) requires enormous storage space. DVD alleviates that restriction. DVD will enable librarians and researchers to do more than simply gain additional control over the bibliographic universe. Quite conceivably, we could see electronic surgery texts on DVD offering more than pictures. With a click of the mouse, readers could be taken from text to a high-quality audio and video demonstration of complex surgical procedures. The possibilities go well beyond this simple example.
Some entertainment DVDs already utilize advanced DVD features. A recent concert on DVD allows viewers to zoom in on selected musicians, and even to increase the relative volume of certain instruments. In our surgical scenario, users would be able to zoom in on various aspects of the surgical procedure, change perspectives in order to observe surgical nursing techniques, the anaesthetist, or to replay in slow motion or in reverse angle, and even to click on icons for more information or lists of references. There is no question that, at least initially, production of such software would be expensive.
The number of DVD drives and titles is set to take off. According to DISK/TREND, shipments of DVD drives will lead CD-ROM drives by 2001 (3). InfoTech predicts that nearly 70 million DVD drives will be installed by 2000 (4). There will be plenty of software to go with the hardware. As early as 1997, 50% of CD-ROM publishers announced plans to develop products on DVD-ROM. At present, more than 1600 titles are available, the majority being movies.
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Storage Technology Association’s efforts to avoid a format war similar to the one that plagued CD development. So far, the history of DVD development has been a history of competition. Only grudgingly have manufacturers come to accept a unified standard for the first two DVD formats.
The DVD Forum’s (Orange Book) DVD-RAM standard has the support of major manufacturers. Nevertheless, Sony is pushing its own ‘DVD+RW’. Philips, despite its alliance with Sony, announced its intention of manufacturing a stand-alone, rewriteable video disc next year. Pioneer is developing its own recordable technology, ‘DVD-RW’. And, if that isn’t enough, Hitachi will launch a DVD camcorder based on an 8cm DVD-RAM disc format, and one developer promises a DVD-RAM navigation system for automobiles. Most proposals for read/write capabilities have compatibility problems with DVD-ROM drives; Sony, for example, has no plans to enable DVD-ROM drives to read DVD-RAM discs. Noncompatibility is something we may have to live with. Some industry analysts suggest that full compatibility may not happen and that several formats will coexist, perhaps all of them incompatible with DVD-ROM. In the immediate future, we can only hope to see the establishment of a unified standard for recordable and rewriteable DVD, one that may or may not be backwards compatible.
New drives are shipped frequently, so keeping up with the latest DVD-RAM technology is extremely difficult. A few competing rewriteable formats and format proposals are indicated in Table 3.
Table 3 - The DVD Forum Standard and some rewriteable formats (5) Manufacturer Format Capacity
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*supported by Hewlett-Packard, MCC/Verbatim, Philips, Ricoh, and Yamaha
Although rewriteable DVD drives are already available, there are indications that widespread market release may not be imminent. The market for CD-R (recordable) and CD-RW (rewriteable) continues to grow at a significant rate, and manufacturers are smart enough to realize that it is not profitable to kill successful products to make way for a new one.
More change is on the way. The industry is anticipating the development of a new system to meet the needs of future data and video storage. One manufacturer is promising to push DVD’s limit by developing a 30GB DVD-RAM by 2005. One can only guess if such new developments will be compatible with today’s DVD drives; nevertheless, they will eventually be successful. DVD will replace CD-ROM simply because it offers clear advantages over it, and because applications developers will publish on DVD at the expense of CD-ROM.
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Appendix Where to get more information DVD Forum http://www.dvdforum.org/ Optical Storage Technology Association http://www.osta.org/ DVD Frequently Asked Questions (with answers!) http://www.videodiscovery.com/vdyweb/dvd/dvdfaq.html EMedia Professional http://www.emediapro.net/ DVD information (from Scandinavia) http://www.unik.no/~robert/hifi/dvd/ DVD FAQs By Kilroy Hughes http://www.icdia.org/dvdfaq02.html C-Cube Microsystems Inc. http://www.c-cube.com/technology/dvd.html DVD Resources http://www.mpeg.org/MPEG/dvd.html DVD Insider http://www.dvdinsider.com/
References 1. Cameron, B.D. Assessing the DVD option in a medical library. Computers in Libraries 1998 Nov/Dec; 18(10): 60-65.
2. Jessop, D.J. DVD basics for libraries and information centers. Computers in Libraries 1998 Apr; 18(4): 62-66.
3. NewMedia Canada 1998 Sept 22; 13(28); see also: http://www.disktrend.com.
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8 (online at: http://www.nikkeibp.asiabiztech.com/Database/1999_Feb/08/Fea.01.gwif.html); see also: Paker, D.J. The many faces of high-density rewriteable optical. Emedia Professional 1998 Jan; 11(1): 6071 (online at: http://www.emediapro.net/EM1998/parker1.html).
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Author Information Brian Cameron, the Information Specialist for the Medical Directorate and Cardiovascular Sciences in the Toronto Hospital Health Sciences Libraries, teaches an internet course and is interested in emerging technologies. Brian graduated from the University of Toronto with an M.L.S. after completing a B.A. at the University of Guelph and an M.A. at Wilfrid Laurier University. Brian is Past-President of the Toronto Health Libraries Association.
