A LaserDisc (left), compared with a DVD. |
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| Media type | Optical disc |
| Encoding | NTSC, PAL |
| Capacity | 60 minutes per side on CLV discs 30 minutes per side on CAV discs |
| Read mechanism | 780 nm wavelength semiconductor laser |
| Developed by | Philips, MCA, and Pioneer |
| Usage | Home video Data Storage |
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| Standards | |
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| See also | |
LaserDisc (LD) was a home video format and the first commercial optical disc storage medium. Initially licensed, sold, and marketed as MCA DiscoVision (also known as simply "DiscoVision") in North America in 1978, the technology was previously referred to internally as Optical Videodisc System, Reflective Optical Videodisc, Laser Optical Videodisc, and Disco-Vision (with a dash), with the first players referring to the format as "Video Long Play". Later, Pioneer Electronics purchased the majority stake in the format and marketed it as both LaserVision (format name) and LaserDisc (brand name) in 1980, with some releases unofficially referring to the medium as "Laser Videodisc".
Although the format was capable of offering higher quality video and audio than its consumer rivals, the VHS and Betamax videocassette systems, it was poorly received in North America.[1] It also remained a largely obscure format in Europe and Australia. However, it was much more popular in Japan and in the more affluent regions of South East Asia, such as Hong Kong, Malaysia and Singapore. Laserdisc was the prevalent rental video medium in Hong Kong during the 1990s.
Significantly, the technologies and concepts behind Laserdisc are the foundation for later and more popular optical disc formats, including Compact Discs and DVDs.
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Laserdisc technology, using a transparent disc,[2] was invented by David Paul Gregg in 1958 (and patented in 1961 and 1990).[3][4] By 1969, Philips had developed a videodisc in reflective mode, which has advantages over the transparent mode. MCA and Philips decided to combine their efforts: they first publicly demonstrated the videodisc in 1972. Laserdisc was first available on the market, in Atlanta, on December 15, 1978,[5] two years after the introduction of the VHS VCR, and four years before the introduction of the CD (which is based on Laserdisc technology). Philips produced the players while MCA produced the discs. The Philips-MCA cooperation was not successful, and discontinued after a few years. Several of the scientists responsible for the early research (Richard Wilkinson, Ray Dakin and John Winslow) founded Optical Disc Corporation (now ODC Nimbus).
In 1979, the Museum of Science and Industry in Chicago opened their "Newspaper" exhibit which used interactive Laserdiscs to allow visitors to search for the front page of any Chicago Tribune newspaper. This was a very early example of public access to electronically stored information in a museum.
The first Laserdisc title marketed in North America was the MCA DiscoVision release of Jaws in 1978. The last two titles released in North America were Paramount's Sleepy Hollow and Bringing Out the Dead in 2000. The last Japanese released movie was the Hong Kong film Tokyo Raiders from Golden Harvest. A dozen or so more titles continued to be released in Japan, until the end of 2001. Production of Laserdisc players continued until January 14, 2009, when Pioneer stopped making them.[6][7][8]
It was estimated that in 1998, Laserdisc players were in approximately 2% of U.S. households (roughly two million).[9] By comparison, in 1999, players were in 10% of Japanese households.[10] Laserdisc was released on June 10, 1981, and a total of 3.6 million Laserdisc players were sold in Japan.[11] A total of 16.8 million Laserdisc players were sold worldwide, of which 9.5 million of them were sold by Pioneer.[6][7][8]
By the early 2000s, Laserdisc was completely replaced by DVD in the North American retail marketplace, as neither players nor software were now produced. Players were still exported to North America from Japan until the end of 2001. The format has retained some popularity among American collectors, and to a greater degree in Japan, where the format was better supported and more prevalent during its life. In Europe, Laserdisc always remained an obscure format. It was, however, chosen by the British Broadcasting Corporation (BBC) for the BBC Domesday Project in the mid-1980s, a school-based project to commemorate 900 years since the original Domesday Book in England.
The standard home video Laserdisc was 11.81 in (30 cm) in diameter and made up of two single-sided aluminum discs layered in plastic. Although appearing similar to compact discs or DVDs, Laserdiscs used analog video stored in the composite domain with analog sound and/or some form of digital audio. However, despite its analog nature, the Laserdisc at its most fundamental level was still recorded as a series of pits and lands much like CDs, DVDs, and even Blu-rays are today.[12] The first Laserdiscs featured in 1978 were entirely analog but the format evolved to incorporate digital stereo sound in CD format (sometimes with a TOSlink or coax output to feed an external DAC), and later multi-channel formats such as Dolby Digital and DTS.
Since digital encoding and compression schemes were either unavailable or impractical in 1978, three encoding formats based on the rotation speed were used:
As Pioneer introduced Digital Audio to Laserdisc in 1985, they further refined the CAA format. CAA55 was introduced in 1985 with a total playback capacity per side of 55 minutes 5 seconds, reducing the video capacity to resolve bandwidth issues with the inclusion of Digital Audio. Several titles released between 1985 and 1987 were analog audio only due to the length of the title and the desire to keep the film on one disc (e.g., Back to the Future). By 1987, Pioneer had overcome the technical challenges and was able to once again encode in CAA60—allowing a total of 60 minutes 5 seconds. Pioneer further refined CAA, offering CAA45—encoding 45 minutes of material, but filling the entire playback surface of the side. Used on only a handful of titles, CAA65 offered 65 minutes 5 seconds of playback time per side. The final variant of CAA is CAA70, which could accommodate 70 minutes of playback time per side. There are not any known uses of this format on the consumer market.
Audio could be stored in either analog or digital format and in a variety of surround sound formats; NTSC discs could carry two analog audio tracks, plus two uncompressed PCM digital audio tracks, which were CD encoded channels, (EFM, CIRC, 16-bit and 44.1 kHz sample rate).[14] PAL discs could carry one pair of audio tracks, either analog or digital; in the UK, the term LaserVision is used to refer to discs with analog sound, while LaserDisc is used for those with digital audio. The digital sound signal in both formats are EFM-encoded as in CD.[14] Dolby Digital (also called AC-3) and DTS—which are now common on DVD titles—first became available on Laserdisc, and Star Wars: Episode I (1999) which was released on Laserdisc in Japan, is among the first home video releases ever to include 6.1 channel Dolby Digital EX Surround.[15] Unlike DVDs, which carry Dolby Digital audio in digital form, Laserdiscs store Dolby Digital in a frequency modulated form within a track normally used for analog audio. Extracting Dolby Digital from a Laserdisc required a player equipped with a special "AC-3 RF" output and an external demodulator in addition to an AC-3 decoder. The demodulator was necessary to convert the 2.88 MHz modulated AC-3 information on the disc into a 384 kbit/s signal that the decoder could handle. DTS audio, when available on a disc, replaced the digital audio tracks; hearing DTS sound required only an S/PDIF compliant digital connection to a DTS decoder.
The two FM audio channels occupied the disc spectrum at 2.3 and 2.8 MHz on NTSC formatted discs and each channel had a 100 kHz FM deviation. The FM audio carrier frequencies were chosen to minimize their visibility in the video image, so that even with a poorly mastered disc, audio carrier beats in the video will be at least -35 dB down, and thus, invisible. Due to the frequencies chosen, the 2.8 MHz audio carrier (Right Channel) and the lower edge of the chroma signal are very close together and if filters are not carefully set during mastering, there can be interference between the two. In addition, high audio levels combined with high chroma levels can cause mutual interference, leading to beats becoming visible in highly saturated areas of the image. To help deal with this, Pioneer decided to implement the CX Noise Reduction System on the analog tracks. By reducing the dynamic range and peak levels of the audio signals stored on the disc, filtering requirements were relaxed and visible beats greatly reduced or eliminated. The CX system gives a total NR effect of 20 dB, but in the interest of better compatibility for non-decoded playback, Pioneer reduced this to only 14 dB of noise reduction (the RCA CED system used the "original" 20 dB CX system). This also relaxed calibration tolerances in players and helped reduce audible pumping if the CX decoder was not calibrated correctly.
At least where the digital audio tracks were concerned, the sound quality was unsurpassed at the time compared to consumer videotape, but the quality of the analog soundtracks varied greatly depending on the disc and, sometimes, the player. Many early and lower-end LD players had poor analog audio components, and many early discs had poorly mastered analog audio tracks, making digital soundtracks in any form most desirable to serious enthusiasts. Early DiscoVision and Laserdisc titles lacked the digital audio option, but many of those movies received digital sound in later re-issues by Universal, and the quality of analog audio tracks generally got far better as time went on. Many discs that had originally carried old analog stereo tracks received new Dolby Stereo and Dolby Surround tracks instead, often in addition to digital tracks, helping boost sound quality. Later analog discs also applied CX Noise Reduction, which improved the signal-noise ratio of their audio.
Both AC-3 and DTS surround audio were clumsily implemented on Laserdiscs, leading to some interesting player- and disc-dependent issues. A disc that included AC-3 audio forfeited the right analog audio channel to the modulated AC-3 RF stream. If the player did not have an AC-3 output available, the next most attractive playback option would be the digital Dolby Surround or stereo audio tracks. The reason for this is the RF signal needs to bypass the audio circuitry in order to be properly processed by the demodulator. If either the player did not support digital audio tracks (common in older players), or the disc did not include digital audio tracks at all (uncommon for a disc which is mastered with an AC-3 track), the only remaining option was to fall back to a monophonic presentation of the left analog audio track. However, many older analog-only players not only failed to output AC-3 streams correctly, but were not even aware of their potential existence. Such a player will happily play the analog audio tracks verbatim, resulting in garbage (static) output in the right channel.
On a DTS disc, digital PCM audio was not available, so if a DTS decoder was also not available, the only option is to fall back to the analog Dolby Surround or stereo audio tracks. In some cases, the analog audio tracks were further made unavailable through replacement with supplementary audio such as isolated scores or audio commentary. This effectively reduced playback of a DTS disc on a non-DTS equipped system to mono audio—or in a handful of cases, no film soundtrack at all.[16]
Only one 5.1 surround sound option existed on a given Laserdisc (either Dolby Digital or DTS), so if surround sound is desired, the disc had to be matched to the capabilities of the playback equipment (LD Player and Receiver/Decoder) by the purchaser. A fully capable Laserdisc playback rig included a newer Laserdisc player that is capable of playing digital tracks, had a digital optical output for digital PCM and DTS audio, would be aware of AC-3 audio tracks, and had an AC-3 coaxial output; an external or internal AC-3 RF demodulator and AC-3 decoder; and a DTS decoder. Many 1990s A/V receivers combined the AC-3 decoder and DTS decoder logic, but an integrated AC-3 demodulator was rare both in Laserdisc players and in later A/V receivers.[17]
The earliest players employed gas Helium-neon laser tubes to read discs and had a red-orange light with a wavelength of 628 nm, while later solid-state players used infrared semiconductor laser diodes with a wavelength of 780 nm. Many Pioneer Model-III (DiscoVision PR-7820), VP-1000, LD-1100, LD-660 and PR-8210s are still in good working order. Both the Magnavox Magnavision and the Pioneer LD players used the same model of laser tube. Optical hobbyists have been known to cannibalize the laser tube machines. From 1978 to 1984, basically all LaserDisc players, either industrial or consumer, used Helium-Neon laser tubes.
In March 1984, Pioneer introduced the first consumer player with a solid-state laser, the LD-700. It was also the first LD player to load from the front and not the top. One year earlier Hitachi introduced an expensive industrial player with a laser diode, but the player, which had poor picture quality due to an inadequate drop-out compensator, was made only in limited quantities. After Pioneer released the LD-700, gas lasers were no longer used in consumer players, despite their advantages, although Philips continued to use gas lasers in their industrial units until 1985. Helium-Neon gas lasers had a shorter-wavelength laser that created a much smaller spot on the disc, leading to better tracking of imperfectly manufactured discs——such as an off-center hole punch or slightly eccentric tracks. The use of a solid state laser diode necessitated the introduction of the tilt-servo mechanism in LD players; this physically tilted the entire laser table, keeping it parallel with the disc, thus ensuring the larger laser beam spot was always perfectly circular and helping to reduce or eliminate crosstalk on warped CLV discs. In addition, the gas laser was less sensitive to external vibration, a must in certain industrial environments, and generated less photon-shot noise than the solid-state laser diode, resulting in a cleaner, less "busy" on-screen image.
The picture produced by the LD-700's laser could be instantly recognized at the time; it was slightly softer, and large expanses of color in the image, such as a blue sky, would show streaking artifacts. Also, the infrared laser did not cope as well with disc manufacturing defects, such as dirt trapped under the surface of the disc (inclusions), an off-center hole or track errors created during mastering, such as track-to-track "kissing" (tracks touching). Because of this, collectors with large MCA DiscoVision collections (DiscoVision discs had just those type of above mentioned defects) tended to use tube-based LaserDisc players since they played these discs better. In addition to being the first LD player to use a laser diode, the Pioneer LD-700 was also the first player ever to have the aforementioned "tilt" servo, which was arguably one of the greatest advances in LD players, providing superior tracking.
Most machines made were single-sided and required the viewer to manually turn the disc over to play the other side. A number of players (all diode laser based) were made that were capable of playing both sides of the disc automatically; at the end of the first side, or at the viewers command, the machine would reverse the direction of the disc's rotation, simultaneously moving the laser pickup head to the other side of the disc, and then initiate playback. Since LD's are made up of two single sided discs glued together, the auto-reverse player would center each disc side individually. Laserdisc players used either a simple U-shaped reversing mechanism, known as "Epsilon Turn", or technique known as "Gamma Turn", where the player physically rotated the laser reading head 180° as it moved from one side of the disc to the other, ensuring that the laser retained the same playback orientation on both sides of the disc. While Pioneer produced some industrial "jukeboxes" that held more than 50 discs, one company offered, for a short time in 1984, a "LaserStack" unit that required the user to physically remove the player lid for installation and attached to the top of the Pioneer LD-600, LD-1100 or the Sylvania/Magnavox clones. LaserStack held up to 10 discs and could automatically load or remove them from the player or change sides in around 15 seconds. A version for the Magnavox Magnavision and Pioneer VP-1000 was announced, as was a model for the front-loading players, but the company went out of business before the units were available. Only one consumer player, the LD-W1 (it was also released industrially too), was made that could hold more than a single disc; the W1 held two discs and could automatically change discs and sides by rotating the entire mechanism, including both the laser and turntable. Electrically, the LD-W1 was identical to the Elite LD-S1. The LD-W1 remained in the Pioneer catalog for many years and received many improvements: While the first 'version' of the W1 had only 2X oversampling and 16-bit D/A converters in the digital audio, the later units had 4X oversampling with 20-bit D/A converters. The video noise reduction was improved too, sharpening the picture and reducing disc noise while eliminating the artifacts it caused. In addition, high-frequency response in the FM video demodulator and A/D-D/A converters was extended and flattened, increasing resolution and reducing visible digital artifacts. The W1's player software was refined too, making disc and side-changing faster—plus, during side or disc changes, it grabbed a still-frame closer to the actual end-of-program instead of just any frame from the side's last five minutes.
The Pioneer PR7820 was the first mass-produced industrial laserdisc player, sold originally as the MCA DiscoVision PR-7820. This unit was used in many GM dealerships as a source of training videos and presentation of GM's new line of cars and trucks in the late 1970s and early 1980s. After MCA DiscoVision shut down, Pioneer continued to sell the player under the Pioneer name as the Pioneer Model-III. The unit was a full Level-III player and could accept a data-dump from discs themselves. It could also be controlled by an external computer and could be gen-locked to external video sources.
The 7820 was the only player ever sold to either the industrial or consumer market that was entirely designed and engineered by the technicians at MCA Disco-Vision and contained all of their preferred design approaches, such as playing the disc with the laser on top (instead of underneath) and moving the disc radially to provide tracking instead of moving the laser radially. MCA engineers designed the player at the DiscoVision labs in Torrance, CA and Universal-Pioneer mass produced it in Japan. The 7820 was such a high quality player that MCA themselves used it at their DiscoVision disc pressing plant in Carson, CA for quality control checks of both master discs and finished sets. Unfortunately, this caused problems because the 7820 could easily play discs that the poorly designed and quite primitive consumer player, the Magnavox VH-8000, simply could not cope with.
In 1980, Discovision Associates released a factory update (it could also be retrofitted to existing 7820s) that reduced disc search times to less than three seconds, and added the ability to jump up to 99 tracks during vertical blanking, giving essentially "instant" searches. An external computer interface box was also made available at the same time which contained additional memory that increased the total size of a disc-based computer program the 7820 could store and execute to 256k.
The 7820 was the first LD player to use solid-state tangential tracking — instead of a tangential tracking mirror, the 7820 used an electronic CCD delay line to provide tangential tracking corrections, giving the player superb color quality. It was not until 1985/6 that the tangential mirror began to be replaced by electronic correction, first by Yamaha in their first consumer LD player, and eventually, by Pioneer themselves.
MCA DiscoVision had no suggested retail price for the PR-7820; depending on the number purchased, it varied from $3,500 to $2,200 per unit if more than 1000 were bought at once. Fully functional 7820s are not easily available on eBay and are nearly impossible to find in fully functional condition. Because they have a steel chassis, weight is a shipping problem.
Most players made after the mid-1980s were capable of also playing audio CDs. These players included a 4.7 in (12 cm) indentation in the loading tray, where the CD would be placed for play. At least one Pioneer model (CLD-M301) also operated as a CD-changer, with several 4.7 in indentations around the circumference of the main tray.
In 1996, the first model DVD/LD combi-player (and first Pioneer DVD player, for that matter) was the Pioneer DVL-9 released in Japan. The Pioneer Elite DVL-90, an updated version, followed by a similar, though supposedly lower-end model, the DVL-700, were released in 1997. Successors to this model include the Pioneer DVL-909, Pioneer DVL-919, and the Pioneer Elite DVL-91. Although the DVD/LD combi players offered competent LD performance, they paled in comparison to high-end LD players such as the Pioneer Elite CLD-99 and the Pioneer Hi-Vision/MUSE HLD-X9.
The Pioneer DVL-909 lacks support for DTS output. However, a modification to the player can allow this player to support DTS streams on DTS discs, essentially turning the DVL-909 into a Pioneer Elite DVL-91.
The last model DVD/LD player was the Japanese only DVL-H9, but the older DVL-919 is still sold in the U.S. and appears on Pioneer's North American website. However, it has not been actively marketed since the late 1990s. The DVL-919 supports DTS output. The DVL-919's DVD section is unremarkable by modern standards, and does not support progressive scan (480p) even though it has component output. As noted above, the LD section, while competent, is inferior to earlier high-end LD players. A few Pioneer dealers offer North American specification DVL-919s, and a unit purchased in April 2004 had a manufacture date of December 2003. Manufacturing of the DVL-919 continued until January 1, 2009, when Pioneer announced[18] that production would cease after a final production run of 3000 DVL-919 and other model laser disc players.
Certain Japanese players—which are considered to be of higher quality or of greater capacity for quality playback than the North American units—are occasionally imported by enthusiasts. These include the CLD-R7G, LD-S9, HLD-X9 and HLD-X0. All four were manufactured by Pioneer and three contained technology that was never officially available in North American Laserdisc players.
The CLD-R7G, LD-S9 and HLD-X9 share a highly advanced comb filter, allowing them to offer a considerable advantage in picture quality over most other LD players when the S-Video connection is used. The comb filter present in these players is unique and is purportedly the finest comb filter ever used in consumer A/V gear: it is still currently in use in Mitsubishi's top-spec CRT rear-projection television sets (the Diamond and now defunct Platinum series sets) and Pioneer's Elite line of rear-projection televisions.
In addition to the advanced comb filter, the HLD-X9 contains a red-laser pickup, which significantly reduces crosstalk and picture-noise levels compared to players with the traditional infrared laser; it can also read through all but the worst cases of laser rot and surface wear. The HLD-X9 was also a MUSE player, capable when properly equipped of playing back high-definition video Laserdiscs, called Hi-Vision or MUSE discs in Japan.
The HLD-X0 was Pioneer's original MUSE player, and is the player of choice for many enthusiasts despite the fact that it lacks the comb filter shared by the R7G, S9 and X9. It was entirely hand built from hand picked electronics and weighed 79 lb (36 kg). Many argue that the newer X9 was a more capable MUSE player but that the X0 had superior performance with standard NTSC discs. Nonetheless, the X9 remained the more popular of the two models, as it included the newer comb filter and is a dual-side player, meaning that double sided discs did not need to be manually flipped over in order for both sides to be played.
PAL laserdiscs had a slightly longer playing time than NTSC discs, but had fewer audio options. PAL discs only have two audio tracks, consisting of either two analog-only tracks on older PAL LDs, or two digital-only tracks on newer discs. In comparison, later NTSC LDs are capable of carrying four tracks (two analog and two digital). On certain releases, one of the analog tracks is used to carry a modulated AC-3 signal for 5.1 channel audio (for decoding and playback by newer LD players with an "AC-3 RF" output). However, older NTSC LDs made before 1984 (such as the original DiscoVision discs) only have two analog audio tracks.
During its development, MCA, which co-owned the technology, referred to it as the Optical Videodisc System, "Reflective Optical Videodisc" or "Laser Optical Videodisc", depending on the document; changing the name once in 1969 to Disco-Vision and then again in 1978 to DiscoVision (without the hyphen), which became the official spelling. Technical documents and brochures produced by MCA Disco-Vision during the early and mid-'70s also used the term "Disco-Vision Records" to refer to the pressed discs. MCA owned the rights to the largest catalog of films in the world during this time, and they manufactured and distributed the DiscoVision releases of those films under the "MCA DiscoVision" software and manufacturing label; consumer sale of those titles began on December 15, 1978, with the aforementioned Jaws.
Philips' preferred name for the format was "VLP", after the Dutch words Video Langspeel-Plaat ("Video long-play disc"), which in English-speaking countries stood for Video Long-Play. The first consumer player, the Magnavox VH-8000 even had the VLP logo on the player. For a while in the early and mid-1970s, Philips also discussed a compatible audio-only format they called "ALP", but that was soon dropped as the Compact Disc system became a non-compatible project in the Philips corporation. Until early 1980, the format had no "official" name; however, the LaserVision Association, made up of MCA, Universal-Pioneer, IBM, and Philips/Magnavox, was formed to standardize the technical specifications of the format (which had been causing problems for the consumer market) and finally named the system officially as "LaserVision".
After its introduction in Japan in 1981, the format was introduced in Europe in 1983 with the LaserVision name although Philips used "VLP" in model designations, such as VLP-600. Philips tried renaming the entire format in 1987 to "CD-Video", and while the name and logo appeared on players and labels for years, the 'official' name of the format remained LaserVision. In the early 1990s, the format's name was finally changed to LaserDisc.
Pioneer Electronics also entered the optical disc market in 1977 as a 50/50 joint-venture with MCA called Universal-Pioneer and manufacturing MCA designed industrial players under the MCA DiscoVision name (the PR-7800 and PR-7820). For the 1980 launch of the first Universal-Pioneer player, the VP-1000, the name became Laser Disc (with a 'rainbow' type logo joining the two words); in 1981, the space was eliminated and the intercap "LaserDisc" became the final and common brand name for the format, although the official name was LaserVision (as seen at the beginning of many LaserDisc releases just before the start of the film). However, as Pioneer reminded numerous video magazines and stores in 1984, LaserDisc was a trademarked word, standing only for LaserVision products manufactured for sale by Pioneer Video or Pioneer Electronics. A 1984 Ray Charles ad for the LD-700 player bore the term "Pioneer LaserDisc brand videodisc player". From 1981 until the early 1990s, all properly licensed discs carried the LaserVision name and logo, even Pioneer Artists titles.
On single sided Laserdiscs mastered by Pioneer, playing the wrong side will cause a still screen to appear with a happy, upside down turtle that has a Laserdisc for a stomach (nicknamed the "Laserdisc Turtle"). The words "Program material is recorded on the other side of this disc" are below the turtle. Other manufacturers used a regular text message without graphics.
During the early years, MCA also manufactured discs for other companies including Paramount, Disney and Warner Bros. Some of them added their own names to the disc jacket to signify that the movie was not owned by MCA. After Discovision Associates shut down in early 1982, Universal Studio's videodisc software label, called MCA Videodisc until 1984, began reissuing many DiscoVision titles. Sadly, quite a few, such as Battlestar Galactica and Jaws, were time-compressed versions of their CAV or CLV DiscoVision originals. The time-compressed CLV re-issue of Jaws no longer had the original soundtrack, having had incidental background music replaced for the videodisc version due to licensing cost (the music would not be available until the THX LaserDisc box set was released in 1995). One Universal/Columbia co-production issued by MCA DiscoVision in both CAV and CLV versions, The Electric Horseman, is still not available in any other home video format with its original score intact; even the most recent DVD release has had substantial music replacements of both instrumental score and Willie Nelson's songs. An MCA release of Universal′s Howard the Duck, sees only the start credits shown in widescreen before changing to 4:3 for the rest of the film. For many years this was the only disc-based release of the film, until widescreen DVD formats were released with extras. Also, the laser disc release of E.T. the Extra-Terrestrial, is the only format to include the cut scene of a young Harrison Ford playing the part of the school headmaster telling off Elliott for letting the frogs free in the biology class.
For a comparison of consumer video resolutions see List of Common Resolutions (Television)
LD had a number of advantages over VHS. It featured a far sharper picture with a horizontal resolution of 425 TVL lines for NTSC and 440 TVL lines for PAL discs, while VHS featured only 240 TVL lines [19] with NTSC. It could handle analog and digital audio where VHS was mostly analog only (VHS can have PCM audio in professional applications but is uncommon), and the NTSC discs could store multiple audio tracks. This allowed for extras like director's commentary tracks and other features to be added on to a film, creating "Special Edition" releases that would not have been possible with VHS. Disc access was random and chapter based, like the DVD format, meaning that one could jump to any point on a given disc very quickly. By comparison, VHS would require tedious rewinding and fast-forwarding to get to specific points. Laserdiscs were initially cheaper than videocassettes to manufacture, because they lacked the moving parts and plastic outer shell that are necessary for VHS tapes to work, and the duplication process was much simpler. A VHS cassette has at least 14 parts including the actual tape while laserdisc has one part with five or six layers. A disc can be stamped out in a matter of seconds whereas duplicating videotape required a complex bulk tape duplication mechanism and was a time-consuming process. However, by the end of the 1980s, average disc-pressing prices were over $5.00 per two-sided disc, due to the large amount of plastic material and the costly glass-mastering process need to make the metal stamper mechanisms. Due to the larger volume of demand, videocassettes quickly became much cheaper to duplicate, costing as little as $1.00 by the beginning of the 1990s.
Laserdiscs potentially had a much longer lifespan than videocassettes. Because the discs were read optically instead of magnetically, no physical contact needs to be made between the player and the disc, except for the player's clamp that holds the disc at its center as it is spun and read. As a result, playback would not wear the information-bearing part of the discs, and properly manufactured LDs would theoretically last beyond one's lifetime (however, see Laser rot, below). By contrast, a VHS tape held all of its picture and sound information on the tape in a magnetic coating which is in contact with the spinning heads on the head drum, causing progressive wear with each use (though later in VHS's lifespan, engineering improvements allowed tapes to be made and played back without contact). Also, the tape was thin and delicate, and it was easy for a player mechanism, especially on a low quality or malfunctioning model, to mishandle the tape and damage it by creasing it, frilling (stretching) its edges, or even breaking it.
Laserdisc was a composite video format: the luminance (black and white) and chrominance (color) information were transmitted in one signal, separated by the receiver. While good comb filters can do so adequately, these two signals cannot be completely separated. On DVDs, data is stored in the form of digital blocks which make up each independent frame. The signal produced is dependent on the equipment used to master the disc. Signals range from composite and split, to YUV and RGB. Depending upon which format is used, this can result in far higher fidelity, particularly at strong color borders or regions of high detail (especially if there is moderate movement in the picture) and low-contrast details like skin tones, where comb filters almost inevitably smudge some detail.
In contrast to the entirely digital DVD, Laserdiscs use only analog video. As the Laserdisc format is not digitally encoded and does not make use of compression techniques, it is immune to video macroblocking (most visible as blockiness during high motion sequences) or contrast banding (subtle visible lines in gradient areas, such as skies or light casts from spotlights) that can be caused by the MPEG-2 encoding process as video is prepared for DVD. However, proprietary human-assisted encoders manually operated by specialist experts can vastly reduce the incidence of artifacts, depending on playing time and image complexity.
DVDs use compressed audio formats such as Dolby Digital and DTS for multichannel sound. Most Laserdiscs were encoded with stereo (often Dolby Surround) CD quality audio 16bit/44.1 kHz tracks as well as analog audio tracks.[20]
DTS-encoded Laserdisc have full-bitrate DTS soundtracks (1,536 kbit/s) instead of the "half" bitrate (768 kbit/s) DTS tracks often used on DVDs.
Laserdisc players can provide a great degree of control over the playback process. Unlike many DVD players, the operator is immediately tied to the transport mechanism: pause, fast-forward, and fast-reverse commands are always accepted. There were no "User Prohibited Options" where content protection code instructs the player to refuse commands to skip a specific part (such as fast forwarding through copyright warnings). However, some DVD players, particularly in the higher-end units, have the ability to ignore the blocking code and play the video without restrictions. With CAV Laserdiscs the user can jump directly to any individual frame of a video simply by entering the frame number on the remote keypad, a feature not common among DVD players. However, some DVD players have cache features which stores a certain amount of the video in RAM which allows the player to index a DVD as quickly as an LD, even down to the frame in some players.
Another advantage of Laserdisc was that damaged spots can be skipped, while a DVD will become unplayable. Some newer DVD players feature a repair+skip algorithm, which alleviates this problem by continuing to play the disc, filling in unreadable areas of the picture with blank space or a frozen frame of the last readable image and sound. The success of this feature depends upon the amount of damage. Laserdisc players, when working in full analog, recover from such errors faster than DVD players. Direct comparison is, however, almost impossible due to the sheer size differences between the two media. A 1 in (3 cm) scratch on a DVD will probably cause more problems than a 1" scratch on an Laserdisc, but a fingerprint taking up 1% of the area of a DVD would almost certainly cause fewer problems than a similar mark covering 1% of the surface of a Laserdisc.
Similar to the CD versus LP sound quality debates common in the audiophile community, some videophiles argue that Laserdisc maintains a "smoother", more "film-like", natural image while DVD still looks slightly more artificial. Early DVD demo discs often had compression or encoding problems, lending additional support to such claims at the time. However, the lower video signal-to-noise ratio of Laserdisc is substantially less than that of DVDs, making DVDs appear sharper and clearer to most viewers.
Laserdisc's support for multiple audio tracks allowed for vast supplemental materials to be included on-disc and made it the first available format for "Special Edition" releases; the 1984 Criterion Collection edition of Citizen Kane is generally credited as being the first "Special Edition" release to home video, and for setting the standard by which future SE discs were measured. The disc provided interviews, commentary tracks, documentaries, still photographs, and other features for historians and collectors.
Despite the advantages over competing technology at the time (namely VHS and Betamax), the format does have drawbacks. The discs are heavy (weighing about one pound each), cumbersome, more prone to damage if mishandled than a VHS tape, and manufacturers did not market LD units with recording capabilities to consumers. Also, because of their size, greater mechanical effort was required to spin the discs at the proper speed, resulting in much more noise generated than other media.
The space-consuming analog video signal of a Laserdisc limited playback duration to 30 minutes (CAV) or 60 minutes (CLV) per side because of the hardware manufacturer's refusal to reduce line count for increased playtime. After one side was finished playing, a disc has to be flipped over in order to continue watching a movie, and some titles fill two or more discs. Many players, especially units built after the mid-1980s, can "flip" discs automatically by rotating the optical pickup to the other side of the disc, but this is accompanied by a pause in the movie during the side change. If the movie is longer than what could be stored on two sides of a single disc, manually swapping to a second disc is necessary at some point during the film. One exception to this rule is the Pioneer LD-W1, which features two disc platters. In addition, perfect still frames and random access to individual still frames is limited only to the more expensive CAV discs, which only had a playing time of approximately 30 minutes per side. In later years, Pioneer and other manufacturers overcame this limitation by incorporating a digital memory buffer, which "grabbed" a single frame from a CLV disc.
The analog information encoded on Laserdiscs does not include any form of built-in checksum or error correction. Because of this, slight dust and scratches on the disc surface can result in read-errors which cause various video quality problems—glitches, streaks, bursts of static, or momentary picture interruptions. In contrast, the digital MPEG-2 format information used on DVDs has built-in error correction which ensures that the signal from a damaged disc will remain identical to that from a perfect disc right up until the point at which damage to the disc surface is so substantial that it prevents the laser from being able to identify usable data.
In addition, Laserdisc video sometimes exhibit a problem known as “crosstalk”. The issue can arise when the laser optical pickup assembly within the player is out of alignment or because the disc is damaged or excessively warped, but it could also occur even with a properly functioning player and a factory-new disc, depending on electrical and mechanical alignment problems. In these instances, the issue arose due to the fact that CLV discs require subtle changes in rotating speed at various points during playback. During a change in speed, the optical pickup inside the player might read video information from a track adjacent to the intended one, causing data from the two tracks to "cross"; the extra video information picked up from that second track shows up as distortion in the picture which looks reminiscent of swirling "barber poles" or rolling lines of static.
Assuming the player's optical pickup is in proper working order, crosstalk distortion normally does not occur during playback of CAV format Laserdiscs, as the rotational speed never varies. However, if the player calibration is out of order or if the CAV disc is faulty or damaged, other problems affecting tracking accuracy can occur. One such problem is "laser lock", where the player reads the same two fields for a given frame over and over again, causing the picture to look frozen as if the movie were paused.
Another significant issue unique to Laserdisc is one involving the inconsistency of playback quality between different makers and models of player. On most televisions, a given DVD player will produce a picture that is visually indistinguishable from other units. Differences in image quality between players only becomes easily apparent on large televisions and substantial leaps in image quality are generally only obtained with expensive, high-end players that allow for post-processing of the MPEG-2 stream during playback. In contrast, Laserdisc playback quality is highly dependent on hardware quality. Major variances in picture quality appear between different makers and models of LD players, even when tested on a low to mid-range television. The obvious benefits of using high quality equipment has helped keep demand for some players high, thus also keeping pricing for those units comparably high. In the 1990s, notable players sold for anywhere from US$200 to well over $1,000, while older and less desirable players could be purchased in working condition for as little as $25.
Many early LDs were not manufactured properly; sometimes a substandard adhesive was used to sandwich together the two sides of the disc. The adhesive contained impurities that were able to penetrate the lacquer seal layer and chemically attack the metalized reflective aluminium layer, causing it to oxidize and lose its reflective characteristics. This was a problem that was coined "laser rot" (or, "LaserRot", after the original official CamelCase "LaserDisc" name of the underlying product) among LD enthusiasts, also called "color flash" internally by laserdisc-pressing plants. Some forms of laser rot could appear as black spots that looked like mold or burned plastic which cause the disc to skip and the movie to exhibit excessive speckling noise. But, for the most part, rotted discs could actually appear perfectly fine to the naked eye.
Later optical standards have been known to suffer similar problems, including a notorious batch of defective CDs manufactured by Philips-DuPont Optical in Europe during the early 1990s.
Laserdisc was poorly received in North America due to the high cost of the players and discs, which were far more expensive than VHS players and tapes, and due to marketplace confusion with the technologically inferior CED, which also went by the name Videodisc. While the format was unsuitable with most North American consumers, it was well received among videophiles and celebrities due to the superior audio and video quality compared to VHS and Betamax tapes. The format was more popular in Japan than in North America because prices were kept low to ensure adoption, resulting in minimal price differences between VHS tapes and the higher quality Laserdiscs, helping ensure that it quickly became the dominant consumer video format in Japan. Anime collectors in every country the LD format was released, which includes both North America and Japan, also quickly became familiar with this format, and sought the higher video and sound quality of laserdisc and the availability of numerous titles not available on VHS. Laserdiscs were also popular alternatives to videocasettes among movie enthusiasts in the more affluent regions of South East Asia, such as Singapore, due to their high integration with the Japanese export market and the disc-based media's superior longevity compared to videocassette, especially in the humid conditions endemic to that area of the world.
The format also became quite popular in Hong Kong during the 1990s before the introduction of VCDs and DVD; although people rarely bought the discs (because each LD is priced around USD100), high rental activity helped the video rental business in the city grow larger than it had ever been previously. Due to integration with the Japanese export market, NTSC laserdiscs were used in the Hong Kong market, in contrast to the PAL standard used for broadcast (This anomaly also exists for DVD). This created a market for multi-system TVs and multi-system VCRs which could display or play both PAL and NTSC materials in addition to SECAM materials (which were never popular in Hong Kong). Some LD players could convert NTSC signals to PAL so that most TVs used in Hong Kong could display the LD materials.
Despite the mild popularity, manufacturers refused to market recordable Laserdisc devices on the consumer market, even though the competing VCR devices could record onto cassette, which hurt sales worldwide. The inconvenient disc size, the high cost of both the players and the media and the inability to record onto the discs combined to take a serious toll on sales, and contributed to the format's poor adoption figures.
Although the Laserdisc format was supplanted by DVD by the late 1990s, many LD titles are still highly coveted by movie enthusiasts (for example, Disney's Song of the South which is unavailable in the US in any format, but was issued in Japan on LD). This is largely because there are many films that are still only available on LD and many other LD releases contain supplemental material not available on subsequent DVD versions of those films. Until the end of 2001, many titles were released on VHS, Laserdisc and DVD in Japan.
LD players are also sometimes still found in contemporary North American high school and college physics classrooms, in order to play a disc of the Physics: Cinema Classics series of mid-20th century Encyclopædia Britannica films reproducing classic experiments in the field which are difficult or impossible to replicate in the laboratories in educational settings.[21] These films have now been released on DVD.[22]
In the early 1980s, Philips produced a Laserdisc player model adapted for a computer interface, dubbed "professional". In 1985, Jasmine Multimedia created laserdisc Juke Boxes featuring music videos from Michael Jackson, Duran Duran, and Cyndi Lauper. When connected to a PC this combination could be used to display images or information for educational or archival purposes, for example thousands of scanned medieval manuscripts. This strange device could be considered a very early equivalent of a CD-ROM.
In 1986, a SCSI-equipped Laserdisc player attached to a BBC Master computer was used for the BBC Domesday Project. The player was referred as an LV-ROM (LaserVision Read Only Memory) as the discs contained the driving software as well as the video frames. The discs used the CAV format, and encoded data as a binary signal represented by the analog audio recording. These discs could contain in each CAV frame video/audio or video/binary data, but not both. "Data" frames would appear blank when played as video. It was typical for each disc to start with the disc catalog (a few blank frames) then the video introduction before the rest of the data. Because the format (based on the ADFS hard disc format) used a starting sector for each file, the data layout effectively skipped over any video frames. If all 54,000 frames are used for data storage an LV-ROM disc can contain 324 MB of data.[23] The Domesday Project systems also included a genlock, allowing video frames, clips and audio to be mixed with graphics originated from the BBC Master; this was used to great effect for displaying high resolution photographs and maps, which could then be zoomed into.
Apple's HyperCard scripting language provided Macintosh computer users with a means to design databases of slides, animation, video and sounds from Laserdiscs and then to create interfaces for users to play specific content from the disc. User-created "stacks" were shared and were especially popular in education where teacher-generated stacks were used to access discs ranging from art collections to basic biological processes. Commercially available stacks were also popular with the Voyager company being possibly the most successful distributor.[24]
Commodore International's 1992 multimedia presentation system for the Amiga, AmigaVision, included device drivers for controlling a number of Laserdisc players through a serial port. Coupled with the Amiga's ability to use a Genlock, this allowed for the Laserdisc video to be overlaid with computer graphics and integrated into presentations and multimedia displays, years before such practice was commonplace.
Pioneer also made computer-controlled units such as the LD-V2000. It had a back-panel RS-232 serial connection through a five-pin DIN connector, and no front-panel controls except Open/Close. (The disc would be played automatically upon insertion.)
Under contract from the U.S. Military, Matrox produced a combination computer laserdisc player for instructional purposes. The computer was a 286, the Laserdisc player only capable of reading the analog audio tracks. Together they weighed 43 lb (20 kg) and sturdy handles were provided in case two people were required to lift the unit. The computer controlled the player via a 25-pin serial port at the back of the player and a ribbon cable connected to a proprietary port on the motherboard. Many of these were sold as surplus by the military during the 1990s, often without the controller software. Nevertheless, it is possible to control the unit by removing the ribbon cable and connecting a serial cable directly from the computer's serial port to the port on the laserdisc player.
The format's instant-access capability made it possible for a new breed of Laserdisc-based video arcade games and several companies saw potential in using Laserdiscs for video games in the 1980s and 1990s, beginning in 1983 with Sega’s Astron Belt. American Laser Games and Cinematronics produced elaborate arcade consoles that used the random-access features to create interactive movies such as Dragon's Lair and Space Ace. Similarly, the Pioneer Laseractive and Halcyon were introduced as home video game consoles that used laserdisc media for their software.
In 1991, several manufacturers announced specifications for what would become known as MUSE Laserdisc, representing a span of almost 15 years until the feats of this HD analog optical disc system would finally be duplicated digitally by HD DVD and Blu-ray. Encoded using NHK's MUSE "Hi-Vision" analogue TV system, MUSE discs would operate like standard Laserdiscs but would contain high-definition 1,125-line (1,035 visible lines) (Sony HDVS) video with a 5:3 aspect ratio. The MUSE players were also capable of playing standard NTSC format discs and are superior in performance to non-MUSE players even with these NTSC discs. The MUSE-capable players had several noteworthy advantages over standard Laserdisc players, including a red laser with a much narrower wavelength than the lasers found in standard players. The red laser was capable of reading through disc defects such as scratches and even mild disc rot that would cause most other players to stop, stutter or drop-out. Crosstalk was not an issue with MUSE discs, and the narrow wavelength of the laser allowed for the virtual elimination of crosstalk with normal discs.
In order to view MUSE encoded discs, it was necessary to have a MUSE decoder in addition to a compatible player. There are televisions with MUSE decoding built-in and set top tuners with decoders that can provide the proper MUSE input. Equipment prices were high, especially for early HDTVs which generally eclipsed US$10,000, and even in Japan the market for MUSE was tiny. Players and discs were never officially sold in North America, although several distributors imported MUSE discs along with other import titles. Terminator 2: Judgment Day, Lawrence of Arabia, A League of Their Own, Bugsy, Close Encounters of the Third Kind, Bram Stoker's Dracula and Chaplin were among the theatrical releases available on MUSE LDs. Several documentaries, including one about Formula One at Japan's Suzuka Circuit were also released.
The most common size of Laserdisc was 11.81 in (30 cm). These approximated the size of 12 in (30 cm) LP vinyl records. These discs allowed for 30 minutes per side (CAV) or 60 minutes per side (CLV). The vast majority of programming for the Laserdisc format was produced on these discs.
A number of 7.9 in (20 cm) Laserdiscs were also published. These smaller "EP"-sized LDs allowed for 20 minutes per side (CLV). They are much rarer than the full-size LDs, especially in North America. These discs were often used for music video compilations (e.g. Bon Jovi′s "Breakout", Bananarama′s "Video Singles" or T'Pau's "View From A Bridge").
There were also 4.7 in (12 cm) "single"-style discs produced that were playable on Laserdisc players. These were referred to as CD Video (CD-V) discs, and Video Single Discs (VSD). A CD-V carried up to five minutes of analog Laserdisc-type video content (usually a music video), as well as up to 20 minutes of digital audio CD tracks. The original 1989 release of David Bowie's restrospective Sound and Vision CD box set prominently featured a CD-V video of Ashes To Ashes, and standalone promo CD-Vs featured the video, plus three audio tracks: John, I'm Only Dancing, Changes and The Supermen.
CD-Vs are not to be confused with Video CDs (which are all-digital and can only be played on VCD players, DVD players, CD-i players, computers, and later-model Laserdisc players, such as the DVL series from Pioneer that can also play DVDs). CD-Vs can only be played back on Laserdisc players with CD-V capability. VSDs were the same as CD-Vs, but without the audio CD tracks. CD-Vs were somewhat popular for a brief time worldwide, but soon faded from view. VSDs were popular only in Japan and other parts of Asia, and were never really introduced to the rest of the world.
Picture discs have artistic etching on one side of the disc to make the disc more visually attractive than the standard shiny silver surface. This etching might look like a movie character, logo, or other promotional material. Sometimes that side of the LD would be made with colored plastic rather than the clear material used for the data side. Picture disc LDs only had video material on one side as the "picture" side could not contain any data. Picture discs are rare in North America.
Pioneer Electronics—one of the format's largest supporters/investors—was also deeply involved in the karaoke business in Japan, and used Laserdiscs as the storage medium for music and additional content such as graphics. The format was generally called LD-G. While several other karaoke labels manufactured Laserdiscs, there was nothing like the breadth of competition in that industry that exists now, as almost all manufacturers have transitioned to CD+G discs (en route, possibly, to a new DVD-based format).
With the release of 16:9 televisions in the mid 1990s, Pioneer and Toshiba decided that it was time to take advantage of this aspect ratio. Squeeze LDs were enhanced 16:9-ratio widescreen Laserdiscs. During the video transfer stage, the movie was stored in an anamorphic "squeezed" format. The widescreen movie image was stretched to fill the entire video frame with less or none of the video resolution wasted to create letterbox bars. The advantage was a 33% greater vertical resolution compared to letterboxed widescreen Laserdisc. This same procedure was used for DVD. Unlike all DVD players, very few LD players had the ability to unsqueeze the image for 4:3 sets. If the discs were played on a 4:3 television the image would be distorted. Since very few people owned 16:9 displays, the marketability of these special discs was very limited.
There were no anamorphic laserdisc titles available in the US except for promotional purposes. Upon purchase of a Toshiba 16:9 television viewers had the option of selecting a number of Warner Brothers 16:9 films. Titles include Unforgiven, Grumpy Old Men, The Fugitive, and Free Willy. The Japanese lineup of titles was different. A series of releases under the banner "SQUEEZE LD" from Pioneer of mostly Carolco titles included Basic Instinct, Stargate, Terminator 2: Judgment Day, Showgirls, Cutthroat Island, and Cliffhanger. Strangely, Terminator 2 was released twice in Squeeze LD, the second release being THX certified and a notable improvement over the first.
Another type of video media, CRVdisc, or "Component Recordable Video Disc" were available for a short time, mostly to professionals. Developed by Sony, CRVdiscs resemble early PC CD-ROM caddies with a disc inside resembling a full-sized LD. CRVdiscs were blank, write-once, read-many media that could be recorded once on each side. CRVdiscs were used largely for backup storage in professional/commercial applications.
Another form of recordable Laserdisc that was completely playback-compatible with the Laserdisc format (unlike CRVdisc with its caddy enclosure) is the RLV, or Recordable LaserVision disc. It was developed and first marketed by the Optical Disc Corporation (ODC, now ODC Nimbus) in 1984. RLV discs, like CRVdisc, are also a WORM technology, and function exactly like a CD-R disc. RLV discs looked almost exactly like standard Laserdiscs, and could play in any standard Laserdisc player after they have been recorded.
The only cosmetic difference between an RLV disc and a regular factory-pressed Laserdiscs was their reflective purple-violet (or blue with some RLV discs) color resulting from the dye embedded in the reflective layer of the disc to make it recordable, as opposed to the silver mirror appearance of regular LDs. The purplish color of RLVs was very similar to present-day DVD-R and DVD+R discs. RLVs were popular for making short-run quantities of Laserdiscs for specialized applications such as interactive kiosks and flight simulators.
In spite of nonrecordability being commonly regarded as the primary weakness of the Laserdisc format, these recordable LD systems were never marketed toward the general public, and are so poorly known as to create the misconception that a home recording system for Laserdiscs was impossible.
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