Digital Media Systems

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DIGITAL MEDIA SYSTEMS

The conversion from analog to digital technology is one of the most fundamental and dramatic changes in modern media. Digital technology is displacing analog at every stage of the production-distribution-exhibition (PDE) process. At the exhibition level, consumers already have a variety of digital devices in their homes, offices, and cars. The computer is the most prominent, but by no means the only, example; compact discs (CDs) have replaced vinyl records, and the digital cell telephone has displaced its analog predecessor. Handheld minicomputers or personal digital assistants (PDAs) are required technology for some executives; answering machines, still cameras, and home video cameras have all made the jump to the digital binary language of zeros and ones. At the production and distribution levels, most media sectors, including broadcast and cable television, the recording industry, and even print media, have been deeply involved in the process of converting to digital. This has all set the stage for what many see as the eventual melding, or convergence, of these previously distinct channels of communication.

There are a number of reasons for the switch to digital. In the analog world, reproduction and distribution of information usually requires some form of copying, such as making additional prints of films or copies of audiotapes. Every time an analog copy is made, however, the quality of the image or sound deteriorates. The more copying that is done from one generation to the next, the greater the loss in original fidelity. Digital communication does not suffer from this handicap. When the equipment is working properly, the last copy in the chain retains all the quality of the original. Converting information to the language of computers also makes it almost infinitely malleable. Audio, video, and textual information that are distinct in the real world are converted into the same currency of digital bits in the computer world, where they can be combined in ways that are limited only by the human imagination. Sights and sounds can be altered, enhanced, created, and destroyed.

Video Production

Traditional analog methods of electronically capturing, assembling, and storing images involved the use of either videotape or film. For image capture, digital cameras began replacing their analog predecessors in the 1990s. While the signals that they generate can be stored and edited on tape, disk storage, which is faster at accessing and transferring material, is usually preferred.

Editing analog videotape, as has been done in television news and entertainment, involves a laborious process of copying segments of images from the original master tape and assembling them into a coherent story, or package. The process requires a sequential, or linear, assembly of shots, like creating a railroad train by adding one car at a time. It does not allow the insertion of one car between two others, nor one scene between two existing shots, without re-editing the full piece. Digital, or nonlinear, editing frees the editor from this constraint. Shots can be arranged and rearranged like a giant jigsaw puzzle with little technical effort. Different compositions can be quickly attempted, discarded, or accepted. Television news uses digital technology to increase dramatically the speed of creating video packages for the evening news.

Film Production

In the motion picture industry, 35-mm film is likely to remain the staple for major studio production and exhibition for many years, largely because of the superior quality of the analog image that is prized by most filmmakers. Nonetheless, many see a day when a large-screen, digital video format will displace film. Rather than making physical copies, or prints, of film for shipment to theaters, some see the instant electronic distribution of digital "films" to multiplexed screens around the world. Meanwhile, filmmakers make use of digital technology in a variety of other ways. Rough cuts, a kind of rough draft of a finished film, can be edited much more quickly using nonlinear editing, with the digital product serving as a guide for the splicing of film for the finished product. Computer-generated special effects are among the most easily recognized digital applications. Nearly any part of a movie or television show can be digitally created or transformed, extending the creative range of television and film artists. Star Wars I: The Phantom Menace, for example, featured extraterrestrial characters that were fabricated through the use of computer animation. In television and film, entire sets, the background setting for a program, can be generated digitally so that an actor or television news anchor appears to be standing in a forest or on a busy city street when in fact he or she is standing in an empty studio.

Home Video and Audio

The power of digital video production is available for home users as well. Digital still-cameras that store images on a disk instead of film are common. On home computers, these images can be cropped, sized, or otherwise altered in hundreds of ways before being printed or sent by e-mailed. Home computers that have the appropriate software can also be used to edit home video, shot on either digital or analog cameras. These digital home movies, edited using the same nonlinear techniques as those that are employed by professionals, can be stored on videotape and played in the family videocassette recorder (VCR). Consumers also can create their own video CDs.

The versatile CD has become the vehicle of choice for many applications. It is the primary medium for recorded music and commercial computer software, and it is increasingly being used in place of videotape for home viewing of theatrical films. In the latter case, manufacturers have adopted the term "DVD" (meaning either digital videodisc or digital versatile disc, depending on the manufacturer). The standard analog videotape player also has a digital companion in the personal video recorder (PVR), which uses computer hard drives to allow a viewer to record and watch a television program, with the full functionality of a VCR (including pause, rewind, and automatic commercial deletion), even while the program is being aired.

For the recording industry, CDs have been supplemented by several other digital technologies, including minidiscs, digital audiotape, and MP3 players that download music from the Internet.

Broadcast Television

The distribution of radio and television programming began migrating to a digital format in 1998 when television stations began their initial digital transmissions. The change means several things. Broadcasters, over time, have to give up their old analog frequencies for the new digital channels and invest hundreds of millions of dollars in new equipment. Because the traditional analog television set cannot use digital signals, every analog television set must eventually be replaced. Converter boxes that translate digital signals into usable analog signals will ease the transition, allowing consumers to make the change at their leisure.

There are a number of benefits for both broadcasters and the public. Digital images, coupled with high-resolution transmission formats, provide sharper, more detailed images. One of the applications of digital television technology is high-definition television (HDTV), which improves the clarity and detail of the home picture. High definition also changes the aspect ratio of television images from the 3 X 4 (three units high by four units wide) dimensions of analog sets to a wider 9 X 16 frame that mirrors the dimensions of a movie screen.

Through digital compression, broadcasters can squeeze more information into their signal and thereby offer new services. For example, programs can be simultaneously broadcast in multiple languages for different audiences. Detailed textual information, such as baseball statistics that viewers can access on-screen during the game, can be fed with the normal programming. Broadcasters can also offer datacasting services, such as paging and Internet access, completely separate from traditional television programming. Digital compression also allows broadcasters to transmit multiple program channels, instead of just one.

Digital Radio

Radio broadcasting has lagged behind television in the migration to digital, but new industry standards for digital radio will, as with television, mean the eventual replacement of all analog receivers in homes and automobiles. Unlike television, however, digital radio will use the same channels as existing analog service, with broadcasters transmitting both digital and analog during the transition period. Conversion to digital means CD-quality sound and allows broadcasters to transmit information about the music, including title, artist, and label, for display on a small screen. Station call letters and formats are also available, and programmable receivers allow drivers to lock automatically onto successive regional jazz stations as they drive across the country. Digital radio technology can also datacast information such as stock market quotes, sports scores, and traffic updates.

In addition to traditional terrestrial broadcasters, nationally distributed satellite digital radio services have emerged. These subscription services beam dozens of audio channels from dedicated communications satellites. Similar to older cable audio services, the channels are divided into special-interest categories from country and western to jazz to opera. Web-based radio stations are also proliferating, and wireless receiving units for them are being developed.

Digital Cable

In the late 1990s, cable television operators began adding digital capacity to their systems, increasing channel capacity and interactivity. Just as in digital broadcasting, cable operators can take a channel that had carried one analog signal and use it to carry multiple digital signals. The increase in channel capacity has meant an increase in consumer program choices. The Discovery Channel, for example, created specialty channels for children, health, aviation, science, and other niche interests. Premium movie services such as Home Box Office and Encore also developed themed or multiplexed channels in categories such as mysteries, westerns, romance, and family entertainment. Digital technology means more pay-per-view movie choices as well. The cable and satellite industry envisions a digital future in which films will be placed on high-capacity servers and customers will be able to order those films whenever they want. Customers need only press a button on their remote control to invoke this video-on-demand (VOD) service. Moreover, the service will provide full VCR functionality; the subscriber will be able to start, stop, and rewind the movie at his or her convenience. Some people see more programming moving to this VOD model, allowing subscribers to order reruns of their favorite old shows, music videos, documentaries, and other material whenever they choose.

Using video streaming—the playing of movies and other video material from digital servers— Internet companies already provide a variety of similar video-on-demand services, although the quality of the image delivered over a standard telephone modem is very poor. Communications companies of all types are looking to marry broadband delivery platforms, such as cable, with video-streaming technology to make instant, on-demand programming a reality.

Digital service also means greater integration of video programming with data for broadcasters, satellite television, and cable operators. Viewers can call up baseball statistics during the game, as noted above, but even greater interaction is possible. In addition to detailed statistics, the living room fans may be able to request a picture-in-picture screen that shows favorite players in old games, or they may be able to change camera angles to watch only the outfielder. Using computer-like pull-down menus, viewers will be able to order tickets to the next game or buy home-team hats and tee-shirts.

Digital Publishing

Newspaper, magazine, and book publishing have all been affected by the digital revolution. One of the most prominent manifestations is their use of the Internet, from the delivery of additional or enhanced content in the case of newspapers, magazines, and journals to book-buying online. Nearly every magazine and newspaper has its own website that features material culled from their print editions and supplemented with additional information, searchable archives, audio and video feeds, and hot links to related sites.

Reinventing the backroom, or production process, in publishing was one of the pioneering steps in digital communications. Newspapers began replacing typewriters with computers in the 1970s, converting over the next two decades to systems in which stories were written, edited, and set in type all within the confines of the computer. In the 1990s, newspaper and magazine photographers began switching from film to digital imagery. Film, which at one time had to be shot in the field, carried back to the newspaper, developed in the lab, printed in the darkroom, and edited physically, can now be transmitted electronically to the newspaper, edited in the computer, and placed in print in a fraction of the time.

The development of "desktop publishing"— which relies on home computers, sophisticated word processing and publishing software, packages full of clip art, and inexpensive digital scan-ners—has turned millions of hobbyists into home publishers, churning out newsletters, pamphlets, and minimagazines for their schools, churches, and civic clubs.

For years, newspaper publishers, and to a lesser extent magazine publishers, sought a means of delivering their product electronically using small, portable wireless readers or flat screens to replace paper. Flat-panel technology is still evolving and may merge with other developing wireless devices. The book publishing industry has also developed electronic book readers. "E-books" can be purchased on disk or downloaded from the World Wide Web and played back, or read, on the flat-screen device that is designed to emulate the sense and feel of a real book. The industry has also considered a "books-on-demand" system in which titles are stored electronically and printed as needed at a local outlet. Using this system, publishers would no longer have to guess about consumer demand and press runs, saving time, money, and natural resources, and there would no longer be such a thing as an out-of-print book.

Wireless

The ubiquitous cell telephone is being replaced by a digital cellular unit, sometimes called a personal communications system (PCS). In addition to improving the clarity of the telephone call, small, built-in screens allow these units to be used for data communication. Users can check their e-mail, trade stocks, or buy gifts online. For more powerful web surfing, the digital telephones serve as wireless modems for laptop computers. Wireless PDAs such as Palm Pilot and two-way, Internet-enabled pagers offer similar tetherless features. Global digital telephone systems that use low-Earth-orbiting satellites are extending this power all over the world.

The Digital Home

The digital future is a switched, broadband, highly interactive information and communication system. A variety of industries, including telephone, cable, television satellite, and even power companies, will vie to provide consumers with bundled packages of telephone service, Internet access, paging, and television programming and present one bill for everything at the end of the month. In the home, it will likely mean high-resolution display screens in as many rooms as the owner wishes. While screens will vary in size— large ones in the family room, small ones in the den—each will have similar capacities to view movies, surf the Internet, look at e-mail, or order dinner. While most home devices may be wired, wireless technologies will be common for any mobile application, from surfing the web on the patio to reviewing voicemail in the car or at the airport. In short, digital technology is changing the way people work, play, and socialize.

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Patrick R. Parsons

Encyclopedia of Communication and Information