Digital Versatile Disc Technology (DVD)
(PowerPoint Slides)
Severine Bennett
Jay Huber
Yanping Wang

Overview of the Technology

DVD (Digital Video Disc or Digital Versatile Disc), is a new medium for the distribution of digital data. A DVD disc looks much the same as a standard audio CD disc and works in much the same way. It is a silvery platter, 12 cm in diameter, with a hole in the center. Like a CD, a DVD disc is divided into tracks and data are stored in a spiral trail of tiny pits on a reflective metal surface embedded in plastic that correspond to the zeros and ones of the digital information contained within the tracks. As the disc revolves, the laser beam follows the spiral, reads the information from the pits, and then plays back that information. But here is where the similarity ends.

In order to store large amounts of diverse information, a disc with a large capacity is essential. DVD achieves this capacity by reducing the track spacing to about half that of a CD, making the pits smaller and the spiral tighter, and by recording the data in as many as four layers, two on each side of the disc by using a semi-transparent gold layer atop the reflective silver-colored layer. In order to read the data, a laser with the ability to read in much finer detail is required. Using a lower-power beam, the laser can read the data from the gold layer; then, with an increase in power, it can access and read the silver layer. While the laser in an ordinary CD-ROM drive has a 780-nanometer (nm) wavelength, DVD drives use lasers with 650-nm or 635-nm wavelengths, thereby supporting more than double the pits per track, and more than double the tracks per recording surface. Other advances, such as a new sector format, better error-correction code, and improved channel modulation, raise the data density an additional one and a  half times. By focusing the laser light through a larger aperture lens, a narrower focus is obtained and high-density reading is achieved.

A DVD disc is comprised of two 0.6 mm thick discs bonded back to back, which not only helps strengthen the disc but gives it the same 1.2 mm thickness as a CD. This bonded configuration also makes these discs less prone to warping due to heat and humidity compared to the single CD disc. Most DVD discs can store 4.7 GB of data on each side, or 9.4 GB total. However, there is a technique for increasing density that will soon result in discs that can hold up to 17 GB of data, the equivalent of 26 normal CD-ROMS. This technique, adding another data layer, would double the capacity of a single side. By making the first layer semi-transparent, a second laser could actually punch through and read the data on the layer beneath. This technique sacrifices a little capacity per side, down to 8.5 GB, but by bonding these two dual-layer sides together, a 17 GB capacity is achieved. Also, through this ability to store data much more tightly, DVD drives throughput can exceed that of a 9x CD-ROM drive, and can transfer data up to 2.7MB per second.
Specification DVD CD
Diameter (mm) 120 120
Disc Thickness (mm) 1.2 1.2
Substrate Thickness (mm) 0.6 1.2
Track Pitch ([micro]meter) 0.74 1.6
Minimum Pit Size ([micro]meter) 0.4 0.83
Wavelength (nm) 635/650 780
Single Layer Capacity (GB) 4.7 0.65

One other aspect of DVD technology that is worth mentioning is the development of special recordable discs. There are three types of recordable discs available: DVD-R, with a capacity of 3.95GB and the ability for one-time recording, DVD-RAM, with a capacity of 2.58GB and the ability to write over and over, and DVD-+RW, with a capacity of 3GB and the ability to write over and over.  All of these recordable formats hold less than the 4.7GB capacity of read-only discs (DVD-ROM). Analysts predict that it will be late 1999 before 4.7 GB will be available on one surface of a DVD-RAM disc.

The large amount of storage capacity is one of the primary features of DVD.  Typically CD/CD-ROMs can store about 650MB of information on a disc, while DVD formats can hold several times as much data.  The actual amount of data a disc can hold depends on the specific DVD format.  The recordable and re-recordable formats are limited to a slightly lower capacity due to the physical processes used to create them.  However, the read-only formats can store 4-17 GB of data, and newer formats are being proposed to store even higher amounts.

The following table shows the capacity for some of the most popular DVD formats:
DVD Format # of Sides # of Layers Capacity (est.) Notes
DVD-5 Single Single 4.7 GB Stores roughly 2 hours of high quality video
DVD-9 Single Double 8.75 GB Stores about 4 hours of high quality video
DVD-10 Double Single 9.4 GB Stores about 4.5 hours of high quality video
DVD-18 Double Double 17 GB Stores over 8 hours of high quality video
DVD-R Single Single 3.95 GB
DVD-R Double Single 7.38 GB
DVD-RAM Single Single 2.6 GB Expected to reach 4.7 GB within a year
DVD-RAM Double Single 5.2 GB
DVD-+RW Single Single 3 GB
DVD-+RW Double Single 6 GB
In the case of DVD-Video, the storage capacity is often discussed in terms of duration - a.k.a. "How long can a movie be and still fit?".  However, this question does not have a clear-cut answer.  The figures vary depending upon the amount of compression used on both the audio and video, as well as the number of audio tracks included.  It is actually possible to fit almost 9 hours worth of video and audio onto a single layer DVD if they are compressed to VHS quality levels, yet most DVD-Videos only fit about 2 hours on the same disc due to their compression selection.

DVD-Video discs can be manufactured for one-fourth the cost of a VHS tape and are much more durable. DVD also has the potential to deliver studio-quality video that’s even crisper and more colorful than that of a laserdisc, with 25 or 30 frames per second full-screen video resolution, multiple data streams for closed captioning and dubbing in multiple languages, virtual reality and high-resolution graphics with text and video support, and parallel video streams for viewing from different angles. DVD’s audio benefits may be best of all, delivering digital surround sound, including Dolby AC-3, which supports six separate channels of high-quality audio. Some experts are even predicting that DVD will be to VHS what the CD was to the long-playing record.   Interesting point: DVD-Video format specifies the application layer as well as the physical and logical layers.  DVD-ROM/RAM/+RW only specify the physical and logical layers and leave the application layer unspecified.

One slight drawback of DVD has to do with access time. Access time is the time required for the drive to locate the required information on a disc. Optical drives like CD and DVD are relatively slow and can demand up to several hundred milliseconds to access information. In fact, because of the massive amount of data and the greater density, DVDs are actually slower than ordinary CD-ROMs. For example, access time for a normal CD is 180ms, while currently available DVD kits sport access times that range between 200 and 470ms.
Another technological issue regarding DVD is the topic of copy protection and the ability for people to make perfect duplicates of the digital data on commercial DVD discs.  Developers of DVD software and movies do not want people to be able to make copies of their products - known as pirate copies - either to other digital devices, or to analog devices.  In order to prevent this from happening, DVD uses four different types of copy protection. (Following descriptions taken from the DVD FAQ -

  1. Analog CPS (Macrovision)

  2. Analog copying, such as copying DVD-Videos to VHS tape, is prevented with a Macrovision 7.0 or similar circuit in every DVD player. The general term is APS (Analog Protection System). Computer video cards with composite or s-video (Y/C) output must also use APS. Macrovision adds a rapidly modulated colorburst signal ("Colorstripe") along with pulses in the vertical blanking signal ("AGC") to the composite video and s-video outputs. This confuses the synchronization and automatic-recording-level circuitry in 95% of consumer VCRs. Unfortunately, it can degrade the picture, especially with old or nonstandard equipment. Macrovision may show up as stripes of color, distortion, rolling, black & white picture, and dark cycling. Macrovision creates severe problems for most line doublers. Macrovision is not present on analog component video output of early players, but is required on newer players such as the Sony S7000 (AGC only, since there is no burst in a component signal). The discs themselves tell the player whether or not to enable Macrovision AGC with or without Colorstripe. The producer of the disc decides what amount of copy protection to enable and then pays Macrovision royalties accordingly. Just as with videotapes, some DVDs are Macrovision-protected and some aren't.
  3. CGMS

  4. Each disc also contains information specifying if the contents can be copied. This is a "serial" copy generation management system (CGMS) designed to prevent copies or copies of copies. The CGMS information is embedded in the outgoing video signal. For CGMS to work, the equipment making the copy must recognize and respect the CGMS. The analog standard (CGMS/A) encodes the data on NTSC line 21. The digital standard (CGMS/D) is not yet finalized, but will apply to digital connections such as IEEE 1394/Firewire. See 4) below.
  5. Content Scrambling System (CSS)

  6. Because of the potential for perfect digital copies, paranoid movie studios forced a deeper copy protection requirement into the DVD-Video standard. Content Scrambling System (CSS) is a form of data encryption to discourage reading media files directly from the disc. Most players have a decryption circuit that decodes the data before displaying it. No unscrambled digital output is allowed until work in progress for secure digital connections is finished. On the computer side, DVD-ROM drives and video display/decoder hardware or software exchange encryption keys so that the video is decrypted just before being displayed by the encoder. This means that many DVD-ROM drives and video display boards have extra hardware (and cost) for movie copy protection. In 1999, all DVD-ROM drives will be required to support regional management in conjunction with CSS. Some drives may allow the user to reset the region a limited number of times; other drives will self-program after a certain number of movies have been played. Makers of equipment used to display DVD-Video (drives, chips, display boards, etc.) must license CSS. There is no charge for a CSS license, but it's currently a lengthy process, so it's recommended that interested parties apply as soon as possible. Near the end of May 1997, CSS licenses were finally granted for software decoding.
  7. Digital CPS

  8. In order to provide for digital connections between components without allowing perfect digital copies, a digital copy protection system has been developed, focused on IEEE 1394/FireWire. The draft proposal was made by Intel, Sony, Hitachi, Matsushita, and Toshiba in Feb. 1998. Content is marked with standard CGMS flags of "copy never" or "copy once." Devices that are digitally connected, such as a DVD player and a digital TV, will exchange keys and authentication certificates to establish a channel. The DVD player will encrypt the encoded video signal as it sends it to the receiving device, which must decrypt it. Digital display devices will be able to receive and display all data. Digital recording devices will only be able to receive data which is not marked "copy never," and they must change the CGMS flags to zero copies if the source is marked for one copy. Digital CPS is designed for the next generation of digital TVs and digital video recorders. It will require new DVD players with digital connectors (such as those provided on DV cameras and decks). These new products probably won't appear before mid 1999. Since the encryption is done by the player, no changes are needed to the existing disc format.
    Movie studios and consumer electronics companies want to make it illegal to defeat DVD copy protection, and are pursuing legislation in the U.S. and other countries. A co-chair of the legal group of the copy protection committee stated, "in the video context, the contemplated legislation should also provide some specific assurances that certain reasonable and customary home recording practices will be permitted, in addition to providing penalties for circumvention." It's not at all clear how this might be "permitted" by a player.

    CSS is allowed for DVD-video content only. Of course, since a DVD-ROM can hold any form of computer data, any desired encryption scheme can be implemented.

    The first three forms of copy protection are optional for the producer of a disc. Movie decryption is also optional for hardware and software playback manufacturers: a player or computer without decryption capability will only be able to play unencrypted movies. Digital CPS is performed by the DVD player, not by the disc developer.

    These copy protection schemes are designed only to guard against casual copying (which the studios claim causes billions of dollars in lost revenue). The goal is to "keep the honest people honest." Even the people who developed the copy protection standards admit that they won't stop well-equipped pirates. There are inexpensive devices that defeat analog copy protection, but Macrovision claims none of the devices are effective against the new Colorstripe feature (yet).

    Macrovision and DigiMarc have proposed a watermark process for DVD, which permanently marks each video frame with visually undetectable information. This can be recognized by video equipment to prevent copying, even when the video is transmitted digitally. New players and other equipment will be required to support watermarking. It's possible to make new watermarked discs compatible with existing players, but movie studios will probably not allow it.

Application & Strategic Uses

Due to its large storage capacity, DVD has a wide variety of applications.  Many of these are not yet in use, as DVD-ROMs are not readily available on the market at low prices, nor are they standard on PCs at this time.  The status of being standard on PCs and lower prices will become reality in the near future, however, and at that time more of these applications will be used, as well as some that may not have been devised yet.  Society will both adjust to what DVD can do, and find uses for it, as well as push the development of DVD even further, giving it more capabilities than it currently has.

In their present state DVDs will best be used for loading software programs and maintaining a huge amount of data for applications that run off of computers’ hard disks.  Another application is getting large amounts of information to consumers.  Some more specific examples of these are discussed below.

DVD’s best applications are for programs that require large amounts of data, and for storage of large databases.  Examples of such applications are some mapping programs and phone number or address listings for the entire United States(such as Microsoft’s Encarta)—or even the world. Encyclopedias and digital photograph databases would also be ideal applications.  Encyclopedias could have vivid photographs and even “live-action”, such as a lion roaring on the screen.  Some of these databases are either in development, or have already been released on CD-ROMs.  Such collections of information that already exist on multiple CD-ROMs could be republished on one DVD through a process known as “repurposing.”  This would obviously cut down on the number of disks required for storage, but it would also decrease the amount of raw materials used to store the same amount of information, which may lead to savings for both the industry and the consumer.

Another application would be within the video game industry.  With the additional storage space on a DVD, games can be condensed from multiple CD-ROMs to one DVD; include more full-motion video clips and better sound; not to mention more variations to the game because of extra data tracks (such as different endings, more characters, or more levels one has to go through within the game).  This will enable games to become more interactive, challenging, and entertaining, as well as have more multimedia content.  Some people feel that the development of video games is what is going to push the development of DVD.

As the above demonstrates, DVD technology is primarily going to impact the computer and entertainment industries via the advent of DVD-ROM and DVD-R respectively.  However, certain other industries may benefit as well.  One potential impact of DVD technology is in the area of distribution of large amounts of electronic information.  Organizations who want to be able to inexpensively distribute large amounts of audio/video/data information may turn to DVDs as the solution.

Consider a college recruiting office and the information they distribute to all prospective students.  Class catalogs, videos of the campus, applications, interactive software, etc. are all becoming common materials distributed by admissions offices at most college campuses.  It would be very beneficial to be able to distribute one DVD which contained all of this information on a single disk.  This could reduce costs for production of the materials on the other mediums as well as distribution costs for mailing these larger, heavier packages.  Clearly there are still costs involved in the production and distribution of a promotional package containing a single DVD, but if this expense became sufficiently cost-effective, the option of delivering their material in this manner would be an interesting alternative.

It is possible to imagine other similar scenarios where an organization has to deliver large volumes of information to their “customers”.  The CD-ROM replaced many former ways of distributing large amounts of data and it is possible for the DVD to perform the same task in an era of ever increasing data volumes.

Although few software applications exist at this time that would require as much space as a DVD has to offer, software tends to expand to the capabilities of the media and beyond.  People within the movie, video game, and computer industries feel that DVD is going to continue to develop over time, as the CD-ROM did, and that people will find ways to use the space on a DVD—and later require even more space!  DVD is still in its infancy, and like with any new technology, both society and the technology have adjustments to make to each other.

Of course, the principal application of DVD at the moment is for films.  The additional storage space on a DVD, as compared to laserdiscs or video tapes, allows for different versions of the same movie on one disk.  Within the same piece of media could be an “R” rated version and a “PG” version, each with voice-overs and subtitles in several languages.  This particular feature enables consumers to have greater flexibility in viewing films within their homes.  The chart below shows a comparison between DVD, LaserDisc, and VHS video tapes in terms of quality, cost, storage capacity, and availability.
DVD LaserDisc VHS
Picture Resolution 500 lines 425 lines 250-270 lines
Primary Audio Format Dolby Digital Dolby Digital Pro-Logic
Storage Capacity 133 min. per layer 30 min./60 min. Max. 3-4 hrs.
Cost of Players Around 500 lbs. 600-2000 lbs. 200-500 lbs.
Cost of Media Around 15-20 lbs. 20-40 lbs. 10-20 lbs.
Size of Media 5 inch diameter 12 inch diameter 7.5 x 4 inches
Number of discs/tapes Around 100 Over 8000 (NTSC) Thousands!
Screen Ratios 16:9 or 4:3 Mostly 16:9 Mostly 4:3
Recordable By 2000? No Yes

There are more applications both now and in the future for DVD.  When it comes to storing one’s own database information on a DVD, the technology is not quite to the point of magnetic disks or tape yet, but the industry is working to make it so that DVD-Rs or DVD-RAMs could potentially be used in place of tapes.  Tapes presently offer storage of large amounts of information, and are typically used within corporations to make backups of their daily or weekly business transactions.  Currently a DVD-R can only be written to once.  In the near future, however, DVD-RAMs will be available, and these disks are rewritable.  There are sacrifices for being able to write to these disks, though.  One is space.  A DVD-R holds 3.95GB of data and a DVD-RAM holds 2.58GB.  This is considerably less than the 4.7GB that read-only DVDs hold.  The amount of data storage space on the DVD-R and the DVD-RAM are expected to increase in the future, but right now they hold only the above amounts.  Another disadvantage of the DVD-RAM is that one cannot do staggered recording on it; one must erase the present data and start from scratch each time.  This is not so much a problem for replacing tapes for backup, but it means that DVD-RAM is not well-suited to dynamic information that is constantly changing, and that would typically be stored in the same location.  This makes recording difficult, but the industry is working to make DVD-RAMs such that they can accommodate staggered recording.

DVD-RAM has certain advantages over other optical disk technologies, such as magneto-optical, for data storage.  This may impact the overall market for data storage media, since DVD-RAM has advantages as to cost, durability, compatibility, and capacity.  As previously mentioned, DVD-RAM may also impact the market for using tape drives as backup devices.  DVDs will be able to store as much data as tapes, and would be advantageous for storing archival information, provided that the media costs are compatible or DVD is less expensive.
Worth noting is that manufacturers are making DVD-ROM drives backward-compatible.  This means that DVD-ROM drives will also be able to read CD-ROMs, allowing customers to upgrade to the new drive, but still be able to use their old software disks.  Additionally, drive manufacturers and content providers have agreed upon an encryption method, so that disks cannot be duplicated.  This is especially important for the movie industry, to ensure that pirated copies of movies on DVD cannot be made and sold on the black market in the US, or overseas.

It is expected that DVD-ROM drives will become standard on PCs in the next few years, which means that consumers do not have long to wait before they can use and enjoy the additional storage capacity of DVD.  And as can be seen from the information contained in this section, there are several applications for DVD already, and certain to be more on the way in the not-so-distant future.  Here are a few potential areas which may benefit from DVD technologies.

Music Industry

Although it is unlikely that music audio CDs will be severely impacted by DVD, it is possible that some music anthologies and even audio books are produced for DVD.  Audio selections which would currently span several audio CDs are the most likely candidates for migration to the DVD format.  Although this is a possibility, the industry would have to see value (profit) in providing the material in this manner.

One area of the music industry which might see an impact from DVD is karaoke.  The capacity of DVDs and the features, such as subtitling and multi-track recording, which are supported by DVD provide a benefit to karaoke.  It would be possible to include a full recording, acoustic recording, backup vocals only recording, etc. on a single DVD.  In addition, a karaoke DVD could include animated subtitles for each recording in a wide variety of languages.

Multimedia-Based Training

In an era when training is critical to keep pace with ever changing technology, and yet companies are trying to reduce travel expenses, it is likely that computer based training (CBT) will play a large part in many organizations.  Sources such as the OmniTech Consulting Group predict that multimedia-based training will see a substantial growth before the year 2000.  They suggest that multimedia-based training will more than double by that time.  We certainly see such a trend here at Carnegie Mellon.  The Heinz School and the Software Engineering Institute (among others) offer distance learning courses, and departments on campus have developed just in time (JIT) lecture and presentation formats for delivering such content.

DVD is an excellent format for delivering such multimedia intensive information to the desktop or television.  DVD-ROMs are an excellent platform for delivering CBT material and DVD-Video could become equally strong in the area of home instruction.  They allow a vast amount of highly interactive information to reside on a single disk.  The benefits of multiple audio tracks, subtitles, branching, menus and other interactive features provide an environment (on both computers and televisions) which should be much more conducive to learning.  Learning sessions can be driven by responses, video footage can provide different angles, a single DVD could be used both at home on a television and at work on a PC, and a workout video never has to be rewound - nor does it wear out from daily usage.  There are many advantages to the DVD format which will directly apply to the area of training.

Portable Computing

The Gartner Group, in a December 1997 research note, suggests that the area most likely to see rapid adoption of DVD-ROM technology is that of notebook computers.  Certainly the current crop of notebook computers includes several options for DVD-ROM drives.  Also, the typical high-end usage of notebooks is for corporate presentations which are often multimedia demanding.  The additional capacity and capabilities of DVD will only enhance the ability to use a notebook computer in such situations.

It is possible that DVD will have an even bigger impact on notebook computing once DVD-RAM/+RW devices are available at this level.  Re-recordable media which are small in physical size and weight, yet large on capacity, are ideal for the notebook user.  These type of devices could potentially replace the standard hard drives, floppy drives and CD-ROM drives on notebooks.  Imagine the ability to open up your notebook computer on a cross-country flight, pick up your e-mail, put the polish on a multimedia presentation for your next stop, and then sit back and relax while viewing the latest movie release on DVD.

Desktop Storage/Backups

At a time when both Quantum and Seagate have introduced 18GB hard drives and a typical desktop PC ships with a 4GB hard drive, it would not be surprising to see DVD-RAM/+RW become widely used on desktop PCs.  The current DVD-RAM/+RW standards provide approximately 3 GB of re-recordable storage on a disk costing an estimated $50.  This would place these type of drives in competition with high capacity, high speed storage options such as Iomegas's Jaz drive.  If the cost of DVD-RAM/+RW dropped to the point where they were a viable alternative (cost wise) to such storage options, then it is likely that users would select DVD as a format for both backups and archives.  It is even possible, much like the case with notebook computers, that users would even consider using DVD drives as a primary storage device.

Economic Impacts Of DVD

It is already being proven that DVD will have an economic impact on the film market.  As previously stated, DVD provides higher quality picture and sound than VHS tapes, yet can be purchased for about the same cost. Before much longer DVD will be available to rent at video stores, such as Blockbuster, which will further impact the film market where rentals are concerned. Therefore, it is likely that DVD will eventually replace VHS tapes.  DVD may even replace current film-projecting systems in cinemas around the world, as patrons would want to view movies on “the big screen” with the best possible picture and sound.  It is probably safe to say that DVD will do to viewing films what the CD did to listening to music.

But after the CD impacted the music industry, it impacted the computer industry.  So, what about telecommunications?  What will DVD do to our use of computers and networks in the future?

As described in the “Overview of the Technology” section, DVDs can hold much more data than a CD.  DVD manufacturers are already devising writable DVDs.  This could become an ideal medium for backing-up large amounts of data, such as a company’s database, that currently needs to be stored on tape.  DVDs would not only make the process of backing-up faster, but would also consolidate the back-up.  The entire database could be stored on just a few slim DVDs, as opposed to several bulky tapes.  Storage of large amounts of data on DVDs, such as databases or plans for items a company manufactures (be it buildings, cars, or widgets), may eventually create a trickle-down effect of savings to consumers—or larger profits for the manufacturers.

It is also likely that DVD will have an impact on networks and their usage.  In order to transmit the amount of data contained on a DVD, a more advanced means of transport would be necessary.  Even if a POTS line could support the amount of data, it would take a very long time to transmit.  ISDN lines may not even be enough.  What this implies is that the more advanced means of transporting data over networks will need to be made available to the general population, whereas they are only available in some areas at the moment.  These lines will also need to be offered at an affordable price, so that the average consumer can afford the service.

It is difficult to say exactly what impacts DVD will have on the computer and telecommunications industries.  However, by following the path of the CD’s impact on these industries and tracking the trends of DVD, we wish to present a proposal of what DVD might be expected to do in the future.

Social Impacts

When considering the impacts of DVD technology on society we must understand that the impact is not one-way, which means that society also influences the creation and development of DVD technology. Before we go into any details on this topic, let us look at a structural model for the relationship between technology and society, which is provided by James McQuivey [reference].

Figure 1 shows the individual/social constructionist view of relationship between technology and society including the influence of time. Technology, society, and individuals interact with each other through a symbol over a period of time. A symbol exists as a reified concept that is somewhat independent of the objective properties of the technology or the subjective experience of the society and individual. To fully appreciate this figure, it is useful to use the notion that all symbols carry a dual role: they are both models of reality and models for reality. To borrow a great example from American culture: a white wedding dress once symbolized the purity of a virgin bride; at the same time, it served as an admonition to all young women that they should desire to be virgin brides.

To apply this model to the relationship between DVD technology and society we must  first know what the particular symbol is in this situation. The symbol here is that DVD can store huge amounts of information and has the multimedia capabilities that are impossible for other data storage methods.

Currently, almost all applications of DVD technology are targeting at the new form of entertaining information – home theater – whether it is in the form of DVD player that is connected to TV or  DVD-ROM that is installed on a PC.  DVD video can offer state-of-the-art visual enhancements for a superior video experience.  With a DVD video, people can conveniently sit at home to enjoy a movie having Dolby Digital Sound and an exceptional picture previously available only in movie theaters. Therefore, with the development of DVD technology and the lowering of its cost, the end result may be fewer and fewer people going to movie theaters. Since most TV sets or computer monitors are not wide-screen, it may also require a new method to record movies.

Compared to regular video, DVD video is easy to use; there is no rewinding or jamming. It also won’t degrade or wear out. The price of DVD is comparable to many videotapes and less expensive than laser discs. Typically they sell for less than $25. The affordability of  DVD movie and music videos is the principal reason for the popularity of DVD.  According to the estimation of the DVD Video Group, approximately 500,000 players have been sold to date since DVD video was first launched in late 1997, compared to just 35,000 compact disc players sold in that format’s first year in 1983. On the software side, the DVD Video Group projects that the number of titles to be released in 1998 will bring the total number of available titles to approximately 1,500.

Society, on the other hand, may also influence the development of the DVD technology through the bridge – the symbol. As DVDs are able to carry more than 8GB of data (double sided), other applications such as libraries, databases, distance learning, etc. will also push DVD technology in certain directions. For example, recordable DVDs are needed for most database applications. A static database is unimaginable and impractical. As a result, Hitachi just announced its recordable DVD-RAM for PCs, and recordable DVD-players are expected to be on the market by the year 2000.

The development history of CD-ROMs is also illustrative, with regard to expectations for the mutual impact between DVD technology and society in the future. CD-ROMs can also store large amounts of information. In its early stage, the targeting was on the capacity for storing volumes of information. Entire libraries can be placed on just a few disks. However, people were not willing to pay for entire libraries of information. As a result, providers turned to emphasizing the multimedia capabilities offered by the CD-ROM. Users’ symbolic expectations also changed after significant interaction with the technology. A related study by McQuivey showed that there were significant differences among expected utility and actual utility of CD-ROM in three of the five surveyed categories. The result is shown in table 1. From table one, it is easy to see that people used CD-ROMs for information and education less than they expected, but played more CD-ROM arcade games than they had expected.
Variable Pairs Means Std.Dev.
Expected to use CD-ROM for information/reference 
Uses CD-ROM for information/reference
Expected to use CD-ROM for Education 
Uses CD-ROM for Education 
Expected to use CD-ROM for arcade games 
Uses CD-ROM for arcade games 
Expected to use CD-ROM for non-game entertainment 
Uses CD-ROM for non-game entertainment 
Expected to use CD-ROM for installation/storage 
Uses CD-ROM for installation/storage 
All scores based on a rating of 1 to 5 where 5 = most important use and 1 = least important use. 

Most of the computer electronics companies have a DVD research and development division to support DVD technology. JVC Company of America, Panasonic Consumer Electronics Company, Philips Consumer Electronics Company, Pioneer Electronics (USA), Samsung North America, Sony Electronics, and Toshiba are among the manufacturers that currently produce DVD video players and DVD-ROM drives.

It should be expected that with the further development of DVD technology, its impact on people and society will change accordingly. The reverse is also true; that changes in society will impact DVD technology. Another good example to look at is the copyright issue brought up by DVD technology that resulted in DVD encryption and the advent of Digital Video Express (Divx). Divx is a new DVD development and  a video rental system for DVD, and is explained below.

At the initial stage of DVD’s development, major motion picture studios feared that the almost-perfect reproductions provided by DVD technology would make the pirating of films rampant. With conventional VHS video tape, the quality falls fast with each copy generation. To get a reasonably good copy on VHS, users must acquire the original or a first generation copy of it. DVD copies, on the other hand, are almost perfect, and a copy of the original and a copy of a hundredth-generation copy are almost identical. This could result in copies spreading fast, from friend to friend, with a resulting drop in the sales of the original version.  There was also concern about copies of films that had already been released on DVD in the United States finding their way to Europe while the films were still playing in theaters there.  If copies were available on DVD, European box office sales and profits would suffer.

Therefore, representatives from the major hardware manufacturers in the DVD consortium, computer manufacturers, motion picture studios, and industry associates joined together and formed the Copyright Protection Technical Working Group’s (CPTWG) subcommittee on DVD technology. The committee came up with complicated copyright protection systems that not only are able to stop copies from DVD to DVD, from DVD to VHS, but also cover regional coding, which means that new titles cannot be played outside the area in which they are bought.

However, even with these cautions, quite a few major studios were reluctant to release new titles with DVDs, worrying about the pirating technology. The Divx system was developed with extraordinary safeguards against movie copying and piracy. It has multiple layers of protection which include individual serialization of players and discs, triple DES encryption, watermarking, and analog copy prevention. With this technique, if you lend a Divx disc to someone else, they will have to pay for a viewing period even if you have already paid for it once – or bought the disc outright. Due to its superior copyright and piracy protection, some major studios (Paramount, Universal, and 20th Century Fox) have committed to make all new titles, and almost a thousand catalog titles, available for release on Divx discs - far more than what is available for DVDs. The immediate consequence is that we will have more choices for what  to watch at home with theater quality.

All the above examples tell us that DVD technology  affects our society within a large area and to a large extent; and on the other hand, that society constantly pushes the improvement of DVD technology. They impact each other and never stop their evolution.

Speed of Adoption

The DVD has not lived up to the original expectations in terms of sales (both hardware and software).  However, it has certainly being accepted more rapidly than most other new technologies in this area.  The introduction of DVD was met with greater sales (again both hardware and software) during its first year than the video cassette recorder (VCR), compact disc (CD), or laserdisc (LD) did during their first years.  Certainly this is a good sign and is a strong indicator that DVD will meet with greater success than many recent technologies (digital compact cassettes - DCC, MiniDiscs - MD, etc.).  Depending on the sources, it is believed that over 500,000 DVD-Video players were sold by the end of 1997 along with 2 million videos.  Additionally, over 300,000 DVD-ROM drives were shipped world-wide by the end of 1997.  Several recent predictions from a variety of sources regarding the saturation of DVD-Video and DVD-ROM include: Although these numbers are a bit divergent, they do show that most major sources believe that the saturation of DVD into the home entertainment (DVD-Video) and computer (DVD-ROM/RAM/+RW) markets will continue to increase over the next 5 years.  While DVD may not replace video cassettes and CDs in the next year or two, it does appear that DVDs represent a strong threat to overtake a variety of current media formats early in the 21st century.

Likely factors in the rate at which DVD technology is adopted include: cost, availability, and standards.  For example, when the cost of a DVD-ROM/RAM/+RW drive drops low enough to compete with the cost of a CD-ROM/R drive, it is likely that consumers will opt to purchase systems with a DVD drive instead (or even replace existing CD drives which fail with DVD drives instead).  In the area of DVD-Video, the availability of titles will have a large impact on consumers' decisions to purchase DVD hardware.  Currently, video collectors tend to favor the laserdisc (LD) format due to its high quality, relative durability, and moderately extensive catalog of titles.  Until the catalog of titles available on DVD grows to a level which compares to LD, it is likely that consumers will be a bit more reluctant to buy into DVD technology.  These are but two examples of how the cost and availability of DVD hardware and software (e.g. movies, computer programs, video games) will play a big role in the adoption of DVD technology in various areas of consumer electronics.

Although cost and availability typically have an impact on most major new technologies, the issue of standards when discussing DVD is a bit more unique.  The current battles over recordable/re-recordable DVD (DVD-RAM/+RW/R) formats are one of the biggest current obstacles.  The battle has been equated to the early years of video cassettes when VHS and Betamax were two proposed standards for video cassettes.  Much like the video cassette battle, the DVD format battle is centered around licensing rights moreso than technological superiority.  Sony, Philips, and Hewlett-Packard are pushing their version of re-recordable DVD format called DVD-+RW.  This format is in competition with the standards announced by the industry consortium - DVD Forum.  The consortium standardized on DVD-RAM as the specification for re-recordable DVDs.  Although several other formats are also being proposed by a few other companies, it appears as though either DVD-RAM (which is expected to be available in the first half of 1998) or DVD-+RW (which is not expected until later in 1998) will be the format of choice (it will be interesting to see if Sony learned anything from their marketing and licensing of Betamax technology and how the superior technology failed due to competing standards).  Regardless of which format is superior, or which format sells better, it is possible that many consumers will decide to delay any purchases because of the lack of standards across all vendors.
One other factor which may impact the future of DVD-ROM is the impending release of Microsoft Windows 98.  DVD-ROM is not going to alleviate the problems associated with configuring hardware on the large installed base of WinTel computers, but Microsoft has suggested that it will include DirectShow (the successor to ActiveMovie and Media Control Interface MCI) in Windows 98 which will provide MPEG-2/DVD support.  Microsoft plans to implement a set of APIs (application programming interfaces) under the name DirectShow and these APIs will provide an abstraction layer between the hardware and the application.  This abstraction layer will make it easier for developers in that they can develop programs without worrying about the actual hardware that will run the program.  Although Microsoft claims that DirectShow will run on Windows 95, it will be fully implemented as part of Windows 98 and Windows NT 5 and their releases are more likely to have an impact on the saturation of DirectShow in the WinTel market.  If Microsoft provides good support for the DVD format within the operating system, it will certainly help DVD developers/manufacturers and increase the likelihood of the formats success.  (NOTE: This is another example where lack of standards is a roadblock to the success of DVD)


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