Capacitance Electronic Disc
The Capacitance Electronic Disc (CED) is an analog video disc playback system developed by Radio Corporation of America (RCA), in which video and audio could be played back on a TV set using a special stylus and high-density groove system similar to phonograph records.
First conceived in 1964, the CED system was widely seen as a technological success which was able to increase the density of a long-playing record by two orders of magnitude.[3] Despite this achievement, the CED system fell victim to poor planning, various conflicts with RCA management, and several technical difficulties that slowed development and stalled production of the system for 17 years—until 1981, by which time it had already been made obsolete by laser videodisc (DiscoVision, later called LaserVision and LaserDisc) as well as Betamax and VHS video cassette formats. Sales for the system were nowhere near projected estimates. In the spring of 1984, RCA announced it was discontinuing player production, but continued the production of videodiscs until 1986, losing an estimated $650 million in the process. RCA had initially intended to release the SKT425 CED player with their high end Dimensia system in late 1984, but cancelled CED player production prior to the Dimensia system's release.[4]
The format was commonly known as "videodisc", leading to much confusion with the contemporaneous LaserDisc format. LaserDiscs are read optically with a laser beam, whereas CED discs are read physically with a stylus (similar to a conventional phonograph record). The two systems are mutually incompatible.
RCA used the brand name "SelectaVision" for the CED system, a name also used for some early RCA brand VCRs,[5] and other experimental projects at RCA.[6][7] The Video High Density system is similar to that of CED.
History[edit]
Beginnings and release[edit]
RCA began developing the videodisc system in 1964, in an attempt to produce a phonograph-like method of reproducing video under the name 'Discpix'. Research and development was slow in the early years, as the RCA CED team originally consisted of only four men,[8] but by 1972, the CED team had produced a disc capable of holding ten minutes of color video (a portion of the Get Smart episode "A Tale of Two Tails", re-titled "Lum Fong").[9]
The first CED prototype discs were multi-layered, consisting of a vinyl substrate, nickel conductive layer, glow-discharge insulating layer and silicone lubricant top layer. Failure to fully solve the stylus/disc wear and manufacturing complexity forced RCA to seek simpler construction of the disc. The final disc was crafted using PVC blended with carbon to make the disc conductive. To preserve stylus and groove life, a thin layer of silicone was applied to the disc as a lubricant.
CED videodiscs were originally conceived as being housed in jackets and handled by hand similar to LP records, but during testing it was shown that exposure to dust caused skipped grooves. If dust was allowed to settle on the discs, the dust would absorb moisture from the air and cement the dust particle to the disc surface, causing the stylus to jump back in a locked groove situation. Thus, an idea was developed in which the disc would be stored and handled in a plastic caddy from which the CED would be extracted by the player so that exposure to dust would be minimized.[10]
After 17 years of research and development, the first CED player (model SFT100W) went on sale on March 22, 1981. A catalog of approximately 50 videodisc titles was released at the same time.[11] The first title to be manufactured was Race for Your Life, Charlie Brown.[11] Fifteen months later, RCA released the SGT200 and SGT250 players, both with stereo sound while the SGT-250 was also the first CED player model to include a wireless remote control. Models with random access were introduced in 1983.
Demise[edit]
Several problems doomed the CED system before it was even introduced. From the early development of the CED system, it was clear that VCRs and home videotape—with their longer storage capacity and recording capabilities—posed a threat to the system.[12] However, development pushed ahead. Once released, sales for the CED players were slow. When the forthcoming system was formally announced in late 1979, RCA had projected annual sales of between five and six million players and 200 to 500 million videodiscs. The company had expected to sell 200,000 players by the end of 1981, but only about half that number had been sold, and there was little improvement in sales throughout 1982 and 1983.[3][13]
The extremely long period of development—caused in part by political turmoil and a great deal of turnover in the high management of RCA—also contributed to the demise of the CED system. RCA had originally slated the videodisc system for a 1977 release; at that point, discs were not able to hold more than 30 minutes of video per side and the nickel-like compound used to make the discs was not sturdy enough for manufacture. Signal degradation was also an issue, as handling the discs was causing them to deteriorate more rapidly than expected, baffling engineers.
Sixty minutes per side rendered it impossible for most movies over 120 minutes to be released on one CED disc. This was easily attainable on VHS and Betamax, as a T-120 VHS, for example (which holds two hours and four minutes of tape), could carry most of these movies. However, this was not the case on CED. Many popular films such as some of the James Bond series, Mary Poppins, Star Trek: The Motion Picture and Return of the Jedi had to be released on two CED discs. All three of these examples were typically seen on one VHS/Betamax cassette.[15]
RCA had projected that by 1985, CED players would be in close to 50% of American homes,[3] but the sales of players continued to drop. RCA cut the prices of CED players and offered incentives to consumers such as rebates and free discs, but sales only slightly improved. RCA management realized that the system would never be profitable and announced the discontinuation of production of CED players on April 4, 1984.[13] Remaining stocks of players were sold by dealers and liquidation retailers for as little as $20 each. Unexpectedly, demand for the videodiscs themselves suddenly became high immediately after the announcement; RCA alerted dealers
and customers that videodiscs would continue to be manufactured and new titles released for at least another three years after the discontinuation of players. Less than a year after this announcement, the sale of discs began to decline, prompting RCA to abandon videodisc production after only two years, in 1986.[2]
The last titles released were The Jewel of the Nile by CBS/Fox Video,[16] and Memories of VideoDisc, a commemorative CED given to many RCA employees involved with the CED project,[17] both in 1986.
Advantages[edit]
CED players, from an early point in their life, appealed to a lower-income market more than VHS, Betamax, and LaserDisc. The video quality (approximately 3 MHz of luma bandwidth for CED[1]) was comparable to or better than a VHS-SP or Betamax-II video, but sub-par compared to LaserDisc (about 5 MHz of luma bandwidth).
CED players were intended to be "low-cost" because they cost around half as much to manufacture as a VCR and had fewer precision parts.[18]
The discs themselves could be inexpensively duplicated, stamped out on slightly-modified audio
LP record presses.
Like VCRs, CED videodisc players had features like rapid forward/reverse and visual search forward/reverse. They also had a pause feature, though it blanked the screen rather than displaying a still image; many players featured a "page mode", during which the current block of four successive frames would be repeatedly displayed.
Since CEDs were a disc-based system, they did not require rewinding. Early discs were available only in monophonic sound, but many later discs were issued in stereo sound. (Mono CED discs were packaged in white protective caddies, while the caddies for stereo discs were blue.) Other discs could be switched between two separate mono audio tracks, providing features such as bilingual audio capability.
Like the LaserDisc and DVD, some CEDs feature random access, allowing users to quickly move to certain parts of the movie. Each side of a CED disc could be split into up to 63 "chapters", or bands. Two late RCA players (the SJT400 and SKT400) could access these bands in any given order. Unlike its laser-based counterparts, the chapters in a CED are based on minutes of the film, not scenes.
Novelty discs and CED-based games were produced whereby accessing the chapters in a specified order would string together a different story each time. However, only a few were produced before the halt of CED player manufacturing,[19] and CEDs are much more prone to wear and tear compared to LaserDisc.
Disadvantages[edit]
In comparison with LaserDisc technology, CEDs suffered from the fact that they were a phonograph-style contact medium: RCA estimated that the number of times a CED could be played back, under ideal conditions, was 500.[20] By comparison, a clean, laser rot-free LaserDisc could, in theory, be played an unlimited number of times (although repeated or careless handling could still result in damage).
Since the CED system used a stylus to read the discs, it was necessary to regularly change the stylus in the player to avoid damage to the videodiscs, while worn and damaged discs also caused problems for consumers. When a disc began to wear, video and audio quality would severely decline, and the disc would begin to skip.[20] Several discs suffered from a condition called "video virus", where a CED would skip a great deal due to dust particles stuck in the grooves of the disc. However, playing the disc several times would generally solve this problem.[21]
Unlike VHS tapes, CEDs (along with LaserDisc) required a disc flip (however, some LaserDisc players were able to read both sides of the disc without physically flipping the disc, achieved by moving the laser from one side of the disc to the other, but this still resulted in a pause of playback during the change) at some point during the course of almost all films as only sixty minutes of video could be stored per side (75 mins on UK PAL discs due to the slower rotation speed); if a feature ran over two hours, it would be necessary to spread the feature over two discs.
In some cases, if a movie's theatrical running time was only slightly longer than two hours, studios would often trim short scenes throughout the movie and/or employ time compression (speeding the extra run time out of the film) in order to avoid the expense of issuing two discs.
This problem was not unique to CEDs: LaserDiscs presented the same difficulty, and some longer features, such as The Ten Commandments (1956), still required more than one tape or disc in the VHS, Beta, and LaserDisc formats. There were no two-disc UK PAL releases.
Less significant disadvantages include lack of support for freeze-frame during pause, since CEDs scanned four frames in one rotation versus one frame per rotation on CAV LaserDisc, while computer technology was not advanced enough at the time to outfit the player with a framebuffer affordably. However, a "page mode" was available on many players that would allow those four frames to be repeated in an endless loop.[22]
CEDs were also larger than VHS tapes, thicker than LaserDiscs, and considerably heavier due to the plastic caddies.
Available material[edit]
Media[edit]
Upon release, 50 titles were available for the CED; along with RCA (which included the company's partnership with Columbia Pictures plus Paramount and Disney releases), CBS Video Enterprises (later CBS/FOX Video) produced the first 50 titles.[14] Eventually, Disney, Metro-Goldwyn-Mayer, Paramount Pictures, MCA, Vestron Video, and other labels began to produce CED discs under their own home video labels, and did so until the end of disc manufacturing in 1986.
Market reception[edit]
Capacitance Electronic Disc's competitors, Philips/Magnavox and Pioneer, instead manufactured optical discs, read with lasers.[25] On April 4, 1984, after sales of only 550,000 players, RCA announced the discontinuation of CED videodisc players.[25] RCA's losses since the product's introduction were eventually estimated at $650 million.[26] The huge financial losses partially resulted in General Electric's acquisition of RCA in 1986, and the abandonment of the "SelectaVision" brand on all RCA video products.[25]