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104-613: In 1983, just a year after the introduction of the compact disc , Kees Schouhamer Immink and Joseph Braat presented the first experiments with erasable magneto-optical compact discs during the 73rd AES Convention in Eindhoven . The technology was introduced commercially in 1985. Although optical, they normally appear as hard disk drives to an operating system and can be formatted with any file system . Magneto-optical drives were common in some countries, such as Japan, but have fallen into disuse. Early drives are 130 mm and have

208-494: A Red Book CD; thus, the mono source material is usually presented as two identical channels in a standard Red Book stereo track (i.e., mirrored mono ); an MP3 CD , can have audio file formats with mono sound. CD-Text is an extension of the Red Book specification for an audio CD that allows for the storage of additional text information (e.g., album name, song name, artist) on a standards-compliant audio CD. The information

312-453: A ferromagnetic material sealed beneath a plastic coating. The only physical contact is during recording when a magnetic head is brought into contact with the side of the disc opposite to the laser, similar to Floptical drives , but not the same. During reading, a laser projects a beam on the disk and, according to the magnetic state of the surface, the reflected light varies due to the magneto-optic Kerr effect . During recording, laser power

416-437: A personal computer hard disk drive . Several other formats were further derived, both pre-pressed and blank user writable, including write-once audio and data storage ( CD-R ), rewritable media ( CD-RW ), Video CD (VCD), Super Video CD (SVCD), Photo CD , Picture CD , Compact Disc-Interactive ( CD-i ), Enhanced Music CD , and Super Audio CD (SACD) which may have a CD-DA layer. The optophone , first presented in 1931,

520-474: A 150-minute playing time, 44,056 Hz sampling rate, 16-bit linear resolution, and cross-interleaved Reed-Solomon coding (CIRC) error correction code —specifications similar to those later settled upon for the standard compact disc format in 1980. Technical details of Sony's digital audio disc were presented during the 62nd AES Convention, held on 13–16 March 1979, in Brussels . Sony's AES technical paper

624-603: A CD. VCDs are playable in dedicated VCD players, most modern DVD-Video players, personal computers, and some video game consoles. The VCD standard was created in 1993 by Sony, Philips, Matsushita , and JVC and is referred to as the White Book standard. Overall picture quality is intended to be comparable to VHS video. Poorly compressed VCD video can sometimes be of lower quality than VHS video, but VCD exhibits block artifacts rather than analog noise and does not deteriorate further with each use. 352×240 (or SIF ) resolution

728-479: A diameter of 20 cm (7.9 in) and a sound quality superior to that of the vinyl record. However, due to the unsatisfactory performance of the analog format, two Philips research engineers recommended a digital format in March 1974. In 1977, Philips then established a laboratory with the mission of creating a digital audio disc. The diameter of Philips's prototype compact disc was set at 11.5 cm (4.5 in),

832-417: A disc played from beginning to end slows its rotation rate during playback. The program area is 86.05 cm and the length of the recordable spiral is 86.05 cm / 1.6 μm = 5.38 km. With a scanning speed of 1.2 m/s, the playing time is 74 minutes or 650 MiB of data on a CD-ROM. A disc with data packed slightly more densely is tolerated by most players (though some old ones fail). Using

936-400: A former member of the task force, gives background information on the many technical decisions made, including the choice of the sampling frequency, playing time, and disc diameter. The task force consisted of around 6 persons, though according to Philips, the compact disc was "invented collectively by a large group of people working as a team". Early milestones in the launch and adoption of

1040-469: A graphics signal (typically, the CD+G player is hooked up to a television set or a computer monitor); these graphics are almost exclusively used to display lyrics on a television set for karaoke performers to sing along with. The CD+G format takes advantage of the channels R through W. These six bits store the graphics information. CD + Extended Graphics (CD+EG, also known as CD+XG) is an improved variant of

1144-759: A higher level of performance than previous magneto-optical drives. LIMDOW drives that shipped in the second half of 1997 has search speeds of less than 15 ms and data transfer rates in excess of 4 Mbit/s, which are fast enough for storing audio and streaming MPEG-2 video. Magneto-optical drives were first offered in NeXT computers. They were later also offered in Canon products. Sony MiniDiscs are magneto-optical, and Sony produces many other formats of magneto-optical media. As of August 2021, Sony continues to manufacture one type of blank MiniDisc available only in Japan;

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1248-563: A joint task force of engineers to design a new digital audio disc. Led by engineers Kees Schouhamer Immink and Toshitada Doi , the research pushed forward laser and optical disc technology. After a year of experimentation and discussion, the task force produced the Red Book CD-DA standard. First published in 1980, the standard was formally adopted by the IEC as an international standard in 1987, with various amendments becoming part of

1352-453: A linear velocity of 1.2 m/s and a narrower track pitch of 1.5 μm increases the playing time to 80 minutes, and data capacity to 700 MiB. Even denser tracks are possible, with semi-standard 90 minute/800 MiB discs having 1.33 μm, and 99 minute/870 MiB having 1.26 μm, but compatibility suffers as density increases. A CD is read by focusing a 780 nm wavelength ( near infrared ) semiconductor laser through

1456-476: A malfunctioning CD writer . Error scanning can reliably predict data losses caused by media deterioration. Support of error scanning differs between vendors and models of optical disc drives , and extended error scanning (known as "advanced error scanning" in Nero DiscSpeed ) has only been available on Plextor and some BenQ optical drives so far, as of 2020. The digital data on a CD begins at

1560-620: A new digital audio disc. After a year of experimentation and discussion, the Red Book CD-DA standard was published in 1980. After their commercial release in 1982, compact discs and their players were extremely popular. Despite costing up to $ 1,000, over 400,000 CD players were sold in the United States between 1983 and 1984. By 1988, CD sales in the United States surpassed those of vinyl LPs, and, by 1992, CD sales surpassed those of prerecorded music-cassette tapes. The success of

1664-448: A new phenomenon, magnetization melting by photoinduced photoconductors, was discovered in magnetic photoconductors. It was demonstrated that extremely low light intensities in the range of 1 μWcm can be used to read/write magnetic information in femtosecond (10 s timescales) allowing high-speed, high-density data storage in principle. Compact disc The compact disc ( CD ) is a digital optical disc data storage format that

1768-531: A private patent licensing organization, had acquired rights from over 20 corporations and one university to license a patent pool of approximately 640 worldwide patents, which it claimed were "essential" to use of MPEG-2 technology. The patent holders included Sony , Mitsubishi Electric , Fujitsu , Panasonic , Scientific Atlanta , Columbia University , Philips , General Instrument , Canon , Hitachi , JVC Kenwood , LG Electronics , NTT , Samsung , Sanyo , Sharp and Toshiba . Where Software patentability

1872-533: A spin-off of Maxtor Corp., was a major manufacturer of 130 mm or 5.25" magneto-optical drives. A current model is the T7-9100 drive, which has a maximum capacity of 9.1 GB and is downward read and write compatible with 5.2 GB, 4.8 GB, 4.1 GB, 2.6 GB, and 2.3 GB magneto-optical disks, and read compatible with 1.3 GB, 1.2 GB, 650 MB, and 600 MB magneto-optical disks. Popular older models of 5.25" Maxoptix MO drives are

1976-460: A variation of this technique called pulse-density modulation (PDM), while Matsushita (now Panasonic ) chose pulse-width modulation (PWM), advertising it as MASH, which is an acronym derived from their patented Multi-stAge noiSe-sHaping PWM topology. The CD was primarily planned as the successor to the vinyl record for playing music, rather than as a data storage medium. However, CDs have grown to encompass other applications. In 1983, following

2080-451: A worm gear is used, a second shorter-throw linear motor, in the form of a coil and magnet, makes fine position adjustments to track eccentricities in the disk at high speed. Some CD drives (particularly those manufactured by Philips during the 1980s and early 1990s) use a swing arm similar to that seen on a gramophone. The pits and lands do not directly represent the 0s and 1s of binary data . Instead, non-return-to-zero, inverted encoding

2184-473: Is a standard for "the generic coding of moving pictures and associated audio information". It describes a combination of lossy video compression and lossy audio data compression methods, which permit storage and transmission of movies using currently available storage media and transmission bandwidth. While MPEG-2 is not as efficient as newer standards such as H.264/AVC and H.265/HEVC , backwards compatibility with existing hardware and software means it

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2288-475: Is backwards-compatible with MPEG-1, allowing MPEG-1 audio decoders to decode the two main stereo components of the presentation. This extension is called MPEG Multichannel or MPEG-2 BC (backwards-compatible). MPEG-2 Part 3 also defines additional bit rates and sampling rates for MPEG-1 Audio Layers I, II, and III. This extension is known as MPEG-2 LSF (low sampling frequencies), since the new sampling rates are one-half multiples (16, 22.05 and 24 kHz) of

2392-407: Is debatable whether Russell's concepts, patents, and prototypes instigated and in some measure influenced the compact disc's design. The compact disc is an evolution of LaserDisc technology, where a focused laser beam is used that enables the high information density required for high-quality digital audio signals. Unlike the prior art by Optophonie and James Russell, the information on the disc

2496-506: Is described in a document produced in 1980 by the format's joint creators, Sony and Philips. The document is known colloquially as the Red Book CD-DA after the color of its cover. The format is a two-channel 16-bit PCM encoding at a 44.1 kHz sampling rate per channel. Four-channel sound was to be an allowable option within the Red Book format, but has never been implemented. Monaural audio has no existing standard on

2600-436: Is heated up to one temperature; but if it is heated up further, it will take its polarity from the other magnetic layer. To write the data onto the disk, the magneto-optical drive's laser pulses between two powers. At high power, the surface heats up more and takes its magnetic charge from the north pole magnetic layer. At the lower power, it heats up less and takes its magnetic charge from the south pole layer. Thus, with LIMDOW

2704-505: Is in some ways less complicated than its predecessor, MPEG-1 Part 3 Audio Layer 3 , in that it does not have the hybrid filter bank. It supports from 1 to 48 channels at sampling rates of 8 to 96 kHz, with multichannel, multilingual, and multiprogram capabilities. AAC is also defined in MPEG-4 Part 3 . MPEG-2 standards are published as "Parts". Each part covers a certain aspect of the whole specification. MPEG-2 evolved out of

2808-454: Is increased to heat the material to the Curie point in a single spot. This enables an electromagnet positioned on the opposite side of the disc to change the local magnetic polarization. The polarization is retained after the temperature drops. Each write cycle requires both a pass to erase a region and another pass to write information. Both passes use the laser to heat the recording layer;

2912-407: Is playable in standard CD players, thus making them backward compatible. CD- MIDI is a format used to store music-performance data, which upon playback is performed by electronic instruments that synthesize the audio. Hence, unlike the original Red Book CD-DA, these recordings are not digitally sampled audio recordings. The CD-MIDI format is defined as an extension of the original Red Book . For

3016-510: Is protected by a film of lacquer normally spin coated directly on the reflective layer. The label is printed on the lacquer layer, usually by screen printing or offset printing . CD data is represented as tiny indentations known as pits , encoded in a spiral track molded into the top of the polycarbonate layer. The areas between pits are known as lands . Each pit is approximately 100  nm deep by 500 nm wide, and varies from 850 nm to 3.5  μm in length. The distance between

3120-522: Is read from a reflective layer using a laser as a light source through a protective substrate. Prototypes were developed by Philips and Sony independently in the late 1970s. Although originally dismissed by Philips Research management as a trivial pursuit, the CD became the primary focus for Philips as the LaserDisc format struggled. In 1979, Sony and Philips set up a joint task force of engineers to design

3224-527: Is split in half over both sides of the disk. The 2.6 GB disks, for example, have a formatted capacity of 1.2 GB per side. The 130 mm drives were always SCSI . The 90 mm discs had their entire capacity on one side, with no capability to flip them over. The 90 mm drives were produced in SCSI, IDE, and USB formats. Capacities range from 128 MB to 2.3 GB. While they were never particularly popular with consumers (the main consumer market

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3328-565: Is still widely used, for example in over-the-air digital television broadcasting and in the DVD-Video standard. MPEG-2 is widely used as the format of digital television signals that are broadcast by terrestrial (over-the-air), cable , and direct broadcast satellite TV systems. It also specifies the format of movies and other programs that are distributed on DVD and similar discs. TV stations , TV receivers , DVD players, and other equipment are often designed to this standard. MPEG-2

3432-432: Is stored either in the lead-in area of the CD, where there are roughly five kilobytes of space available or in the subcode channels R to W on the disc, which can store about 31 megabytes. Compact Disc + Graphics is a special audio compact disc that contains graphics data in addition to the audio data on the disc. The disc can be played on a regular audio CD player, but when played on a special CD+G player, it can output

3536-432: Is supported, Blu-ray does not support MPEG-2 audio (parts 3 and 7). Additionally, the container format used on Blu-ray discs is an MPEG-2 transport stream, regardless of which audio and video codecs are used. As of January 3, 2024, MPEG-2 patents have expired worldwide, with the exception of only Malaysia, where the last patent is expected to expire in 2035. The last US patent expired on February 23, 2018. MPEG LA ,

3640-567: Is the core of most digital television and DVD formats, it does not completely specify them. Regional institutions can adapt it to their needs by restricting and augmenting aspects of the standard. See Video profiles and levels . MPEG-2 Part 1 (ISO/IEC 13818-1 and ITU-T Rec. H.222.0 ), titled Systems , defines two distinct, but related, container formats . One is the transport stream , a data packet format designed to transmit one data packet in four ATM data packets for streaming digital video and audio over fixed or mobile transmission mediums, where

3744-538: Is upheld and patents have not expired (only Malaysia), the use of MPEG-2 requires the payment of licensing fees to the patent holders. Other patents were licensed by Audio MPEG, Inc. The development of the standard itself took less time than the patent negotiations. Patent pooling between essential and peripheral patent holders in the MPEG-2 pool was the subject of a study by the University of Wisconsin. According to

3848-426: Is used on Blu-ray discs, AVCHD on re-writable DVDs and HDV on compact flash cards. Program stream files include VOB on DVDs and Enhanced VOB on the short lived HD DVD . The standard MPEG-2 transport stream contains packets of 188 bytes. M2TS prepends each packet with 4 bytes containing a 2-bit copy permission indicator and 30-bit timestamp. ISO authorized the " SMPTE Registration Authority, LLC" as

3952-559: Is used to follow the optical tracks, while a magnetic head touches the recording surface. The drives can also read and write traditional 3.5" diskettes, although not the 2.88 megabyte variety. Flopticals were manufactured by Insite Peripherals, a company founded by Jim Burke. At the Consumer Electronics Show in January 2004, Sony revealed a 1 gigabyte capacity MiniDisc called Hi-MD . Its recorders can also double

4056-408: Is used: a change from either pit to land or land to pit indicates a 1, while no change indicates a series of 0s. There must be at least two, and no more than ten 0s between each 1, which is defined by the length of the pit. This, in turn, is decoded by reversing the eight-to-fourteen modulation used in mastering the disc, and then reversing the cross-interleaved Reed–Solomon coding , finally revealing

4160-552: Is written without any concurrent data integrity checking. Using a magneto-optical disc is much more like using a diskette drive than a CD-RW drive. During a read cycle, the laser is operated at a lower power setting, emitting polarized light. The reflected light has a change in Kerr rotation and Kerr ellipticity which is measured by an analyzer and corresponds to either a logical 0 or 1. The 130 mm drives have been available in capacities from 650 MB to 9.2 GB. However, this

4264-483: The Compact Disc + Graphics (CD+G) format. Like CD+G, CD+EG uses basic CD-ROM features to display text and video information in addition to the music being played. This extra data is stored in subcode channels R-W. Very few CD+EG discs have been published. Super Audio CD (SACD) is a high-resolution, read-only optical audio disc format that was designed to provide higher-fidelity digital audio reproduction than

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4368-520: The DVB standard: Allowed resolutions for SDTV : For HDTV: The ATSC A/53 standard used in the United States, uses MPEG-2 video at the Main Profile @ High Level (MP@HL), with additional restrictions such as the maximum bitrate of 19.39 Mbit/s for broadcast television and 38.8 Mbit/s for cable television, 4:2:0 chroma subsampling format, and mandatory colorimetry information. ATSC allows

4472-522: The Red Book . Introduced in 1999, it was developed by Sony and Philips, the same companies that created the Red Book . SACD was in a format war with DVD-Audio , but neither has replaced audio CDs. The SACD standard is referred to as the Scarlet Book standard. Titles in the SACD format can be issued as hybrid discs; these discs contain the SACD audio stream as well as a standard audio CD layer which

4576-752: The vinyl revival . During the 2010s, the increasing popularity of solid-state media and music streaming services caused automakers to remove automotive CD players in favor of minijack auxiliary inputs, wired connections to USB devices and wireless Bluetooth connections. Automakers viewed CD players as using up valuable space and taking up weight which could be reallocated to more popular features, like large touchscreens. By 2021, only Lexus and General Motors were still including CD players as standard equipment with certain vehicles. CDs continued to be strong in some markets such as Japan where 132 million units were produced in 2019. The decline in CD sales has slowed in recent years; in 2021, CD sales increased in

4680-716: The 120 mm size was adopted. The adoption of EFM in June 1980 allowed 30 percent more playing time that would have resulted in 97 minutes for 120 mm diameter or 74 minutes for a disc as small as 100 millimetres (3.9 in). Instead, the information density was lowered by 30 percent to keep the playing time at 74 minutes. The 120 mm diameter has been adopted by subsequent formats, including Super Audio CD , DVD , HD DVD , and Blu-ray Disc. The 80-millimetre (3.1 in) diameter discs (" Mini CDs ") can hold up to 24 minutes of music or 210 MiB. The logical format of an audio CD (officially Compact Disc Digital Audio or CD-DA)

4784-611: The 2000s designed as successors to the CD: the Super Audio CD (SACD) and DVD-Audio . However neither of these were adopted partly due to increased relevance of digital (virtual) music and the apparent lack of audible improvements in audio quality to most human ears. These effectively extended the CD's longevity in the music market. With the advent and popularity of Internet-based distribution of files in lossy-compressed audio formats such as MP3 , sales of CDs began to decline in

4888-502: The 2000s. For example, between 2000 and 2008, despite overall growth in music sales and one anomalous year of increase, major-label CD sales declined overall by 20%. Despite rapidly declining sales year-over-year, the pervasiveness of the technology lingered for a time, with companies placing CDs in pharmacies, supermarkets, and filling station convenience stores to target buyers less likely to be able to use Internet-based distribution. In 2012, CDs and DVDs made up only 34% of music sales in

4992-467: The CD's introduction, Immink and Joseph Braat presented the first experiments with erasable compact discs during the 73rd AES Convention . In June 1985, the computer-readable CD-ROM (read-only memory) and, in 1990, recordable CD-R discs were introduced. Recordable CDs became an alternative to tape for recording and distributing music and could be duplicated without degradation in sound quality. Other newer video formats such as DVD and Blu-ray use

5096-475: The DAC. Even when using high-precision components, this approach was prone to decoding errors. Another issue was jitter , a time-related defect. Confronted with the instability of DACs, manufacturers initially turned to increasing the number of bits in the DAC and using several DACs per audio channel, averaging their output. This increased the cost of CD players but did not solve the core problem. A breakthrough in

5200-451: The MPEG-2 licensing agreement any use of MPEG-2 technology in countries with active patents (Malaysia) is subject to royalties . MPEG-2 encoders and decoders are subject to $ 0.35 per unit. Also, any packaged medium (DVDs/Data Streams) is subject to licence fees according to length of recording/broadcast. The royalties were previously priced higher but were lowered at several points, most recently on January 1, 2018. An earlier criticism of

5304-501: The T6 Star, T6-5200 and T5-2600 MO drives. Maxoptix was acquired by Techware Distribution in 2008. Fujitsu was a major manufacturer of 90 mm magneto-optical drives, exceeding 2 GB in capacity, but they have discontinued production and sale of this product category. PDO Konica Minolta was the last manufacturer of 90 mm 3.5" magneto-optical drives. They had a 3.5" 1.3 GB USB external pocket drive available for sale in

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5408-451: The US for the first time since 2004, with Axios citing its rise to "young people who are finding they like hard copies of music in the digital age". It came at the same time as both vinyl and cassette reached sales levels not seen in 30 years. The RIAA reported that CD revenue made a dip in 2022, before increasing again in 2023 and overtook downloading for the first time in over a decade. In

5512-521: The US, 33.4 million CD albums were sold in the year 2022. In France in 2023, 10.5 million CDs were sold, almost double that of vinyl, but both of them represented generated 12% each of the French music industry revenues. Sony and Philips received praise for the development of the compact disc from professional organizations. These awards include: A CD is made from 1.2-millimetre (0.047 in) thick, polycarbonate plastic, and weighs 14–33 grams. From

5616-421: The United States and Europe. Magneto-optical drives are not Floptical drives, which likewise combine ferromagnetic and optical technologies, albeit in a different manner. Flopticals are 21 megabyte 3.5" magnetic diskettes using optical tracks to increase the tracking precision of the magnetic head, from the usual 135 tracks per inch to 1,250 tracks per inch. No laser or heating is involved; a simple infrared LED

5720-412: The United States and elsewhere. The DVD-Video standard uses MPEG-2 video, but imposes some restrictions: HDV is a format for recording and playback of high-definition MPEG-2 video on a DV cassette tape. MOD and TOD are recording formats for use in consumer digital file-based camcorders. XDCAM is a professional file-based video recording format. Application-specific restrictions on MPEG-2 video in

5824-620: The United States. By 2015, only 24% of music in the United States was purchased on physical media, two thirds of this consisting of CDs; however, in the same year in Japan, over 80% of music was bought on CDs and other physical formats. In 2018, U.S. CD sales were 52 million units—less than 6% of the peak sales volume in 2000. In the UK, 32 million units were sold, almost 100 million fewer than in 2008. In 2018, Best Buy announced plans to decrease their focus on CD sales, however, while continuing to sell records, sales of which are growing during

5928-591: The beginning and the end of the stream may not be identified, such as radio frequency , cable and linear recording mediums, examples of which include ATSC / DVB / ISDB / SBTVD broadcasting, and HDV recording on tape. The other is the program stream , an extended version of the MPEG-1 container format with less overhead than transport stream . Program stream is designed for random access storage mediums such as hard disk drives , optical discs and flash memory . Transport stream file formats include M2TS , which

6032-406: The bottom of the polycarbonate layer. The change in height between pits and lands results in a difference in the way the light is reflected. Because the pits are indented into the top layer of the disc and are read through the transparent polycarbonate base, the pits form bumps when read. The laser hits the disc, casting a circle of light wider than the modulated spiral track reflecting partially from

6136-463: The capacity of regular MiniDiscs with special formatting that renders the disc incompatible with other recorders. As with all removable storage media, the advent of cheap CD and DVD drives and flash memory has made them largely obsolete. Magneto-optical disks in particular were expensive when new, with high reliability but slow writing. Magnetic tape formats like LTO have far surpassed MO media for high capacity enterprise-grade backup storage. In 2016

6240-451: The center of the disc and proceeds toward the edge, which allows adaptation to the different sizes available. Standard CDs are available in two sizes. By far, the most common is 120 millimetres (4.7 in) in diameter, with a 74-, 80, 90, or 99-minute audio capacity and a 650, 700, 800, or 870 MiB (737,280,000-byte) data capacity. Discs are 1.2 millimetres (0.047 in) thick, with a 15 millimetres (0.59 in) center hole. The size of

6344-407: The center outward, components are: the center spindle hole (15 mm), the first-transition area (clamping ring), the clamping area (stacking ring), the second-transition area (mirror band), the program (data) area, and the rim. The inner program area occupies a radius from 25 to 58 mm. A thin layer of aluminum or, more rarely, gold is applied to the surface, making it reflective. The metal

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6448-505: The characteristics of the underlying private data. MPEG-2 Part 2 (ISO/IEC 13818-2 and ITU-T Rec. H.262), titled Video , is similar to the previous MPEG-1 Part 2 standard, but adds support for interlaced video , the format used by analog broadcast TV systems. MPEG-2 video is not optimized for low bit rates , especially less than 1 Mbit/s at standard-definition resolutions. All standards-compliant MPEG-2 Video decoders are fully capable of playing back MPEG-1 Video streams conforming to

6552-450: The compact disc has been credited to the cooperation between Philips and Sony, which together agreed upon and developed compatible hardware. The unified design of the compact disc allowed consumers to purchase any disc or player from any company and allowed the CD to dominate the at-home music market unchallenged. In 1974, Lou Ottens, director of the audio division of Philips, started a small group to develop an analog optical audio disc with

6656-477: The constrained parameters bitstream (CPB) limits. With some enhancements, MPEG-2 Video and Systems are also used in some HDTV transmission systems, and is the standard format for over-the-air ATSC digital television. MPEG-2 introduces new audio encoding methods compared to MPEG-1: MPEG-2 Part 3 (ISO/IEC 13818-3), titled Audio , enhances MPEG-1 's audio by allowing the coding of audio programs with more than two channels , up to 5.1 multichannel. This method

6760-627: The decoder to interlace them and perform 3:2 pulldown before display. This allows broadcasters to switch between 60 Hz interlaced (news, soap operas) and 24 Hz progressive (prime-time) content without ending the MPEG-2 sequence and introducing several seconds of delay as the TV switches formats. This is the reason why 1080p30 and 1080p24 sequences allowed by the ATSC specification are not used in practice. The 1080-line formats are encoded with 1920 × 1088 pixel luma matrices and 960 × 540 chroma matrices, but

6864-423: The diagonal of an audio cassette. Heitaro Nakajima , who developed an early digital audio recorder within Japan's national public broadcasting organization, NHK , in 1970, became general manager of Sony's audio department in 1971. In 1973, his team developed a digital PCM adaptor that made audio recordings using a Betamax video recorder. After this, in 1974 the leap to storing digital audio on an optical disc

6968-406: The entire market share in regard to US music sales . The CD is considered the last dominant audio format of the album era , as the rise of MP3 , iTunes , cellular ringtones , and other downloadable music formats in the mid-2000s ended the decade-long dominance of the CD. The format was later adapted (as CD-ROM ) for general purpose data storage and initially could hold much more data than

7072-553: The first MPEG-2 SAVI (System/Audio/Video) decoder in 1995. .mpg, .mpeg, .m2v, .mp2, . mp3 are some of a number of filename extensions used for MPEG-1 or MPEG-2 audio and video file formats. File extension MP3 (formally MPEG-1 Audio Layer III or MPEG-2 Audio Layer III ) is a coding format for digital audio developed largely by the Fraunhofer Society in Germany, with support from other digital scientists in

7176-516: The first few years of its existence, the CD was a medium used purely for audio. In 1988, the Yellow Book CD-ROM standard was established by Sony and Philips, which defined a non-volatile optical data computer data storage medium using the same physical format as audio compact discs, readable by a computer with a CD-ROM drive. Video CD (VCD, View CD, and Compact Disc digital video) is a standard digital format for storing video media on

7280-463: The first four UK albums by the Beatles were released in mono on compact disc. The growing acceptance of the CD in 1983 marks the beginning of the popular digital audio revolution. It was enthusiastically received, especially in the early-adopting classical music and audiophile communities, and its handling quality received particular praise. As the price of players gradually came down, and with

7384-450: The following video resolutions, aspect ratios, and frame/field rates: ATSC standard A/63 defines additional resolutions and aspect rates for 50 Hz (PAL) signal. The ATSC specification and MPEG-2 allow the use of progressive frames, even within an interlaced video sequence. For example, a station that transmits 1080i60 video sequence can use a coding method where those 60 fields are coded with 24 progressive frames and metadata instructs

7488-813: The format included: The first artist to sell a million copies on CD was Dire Straits , with their 1985 album Brothers in Arms . One of the first CD markets was devoted to reissuing popular music whose commercial potential was already proven. The first major artist to have their entire catalog converted to CD was David Bowie , whose first fourteen studio albums (up to Scary Monsters (and Super Creeps) ) of (then) sixteen were made available by RCA Records in February 1985, along with four greatest hits albums; his fifteenth and sixteenth albums ( Let's Dance and Tonight , respectively) had already been issued on CD by EMI Records in 1983 and 1984, respectively. On 26 February 1987,

7592-530: The hole was chosen by Joop Sinjou and based on a Dutch 10-cent coin: a dubbeltje . Philips/Sony patented the physical dimensions. The official Philips history says the capacity was specified by Sony executive Norio Ohga to be able to contain the entirety of Beethoven's Ninth Symphony on one disc. This is a myth according to Kees Immink , as the EFM code format had not yet been decided in December 1979, when

7696-505: The introduction of the portable Discman , the CD began to gain popularity in the larger popular and rock music markets. With the rise in CD sales, pre-recorded cassette tape sales began to decline in the late 1980s; CD sales overtook cassette sales in the early 1990s. In 1988, 400 million CDs were manufactured by 50 pressing plants around the world. Early CD players employed binary-weighted digital-to-analog converters (DAC), which contained individual electrical components for each bit of

7800-476: The label side of the disc. Scratches on the clear side can be repaired by refilling them with similar refractive plastic or by careful polishing. The edges of CDs are sometimes incompletely sealed, allowing gases and liquids to enter the CD and corrode the metal reflective layer and/or interfere with the focus of the laser on the pits, a condition known as disc rot . The fungus Geotrichum candidum has been found—under conditions of high heat and humidity—to consume

7904-510: The lands and partially from the top of any bumps where they are present. As the laser passes over a pit (bump), its height means that the round trip path of the light reflected from its peak is 1/2 wavelength out of phase with the light reflected from the land around it. This is because the height of a bump is around 1/4 of the wavelength of the light used, so the light falls 1/4 out of phase before reflection and another 1/4 wavelength out of phase after reflection. This causes partial cancellation of

8008-419: The laser's reflection from the surface. By measuring the reflected intensity change with a photodiode , a modulated signal is read back from the disc. To accommodate the spiral pattern of data, the laser is placed on a mobile mechanism within the disc tray of any CD player. This mechanism typically takes the form of a sled that moves along a rail. The sled can be driven by a worm gear or linear motor . Where

8112-485: The last 8 lines are discarded by the MPEG-2 decoding and display process. ATSC A/72 is the newest revision of ATSC standards for digital television, which allows the use of H.264/AVC video coding format and 1080p60 signal. MPEG-2 audio was a contender for the ATSC standard during the DTV " Grand Alliance " shootout, but lost out to Dolby AC-3 . Technical features of MPEG-2 in ATSC are also valid for ISDB-T , except that in

8216-428: The late 1980s culminated in development of the 1-bit DAC , which converts high-resolution low-frequency digital input signal into a lower-resolution high-frequency signal that is mapped to voltages and then smoothed with an analog filter. The temporary use of a lower-resolution signal simplified circuit design and improved efficiency, which is why it became dominant in CD players starting from the early 1990s. Philips used

8320-425: The magnetic field is used to change the magnetic orientation of the recording layer. The electromagnet reverses polarity for writing, and the laser is pulsed to record spots of "1" over the erased region of "0". As a result of this two-pass process, it takes twice as long to write data as it does to read it. In 1990, a 300 mm disc with 7 GB capacity was made available. In 1996, Direct Overwrite technology

8424-411: The magneto-optical write process has a single stage, improving write times. Because the magnetic surface is adjacent to the writing surface, rather than somewhere outside the disk itself, the magnetic writing can be done at a higher resolution, including that of the resolution of the laser spot doing the heating up. In the spring of 1997 Plasmon launched its DW260 drive, which used LIMDOW technology for

8528-500: The main TS has aggregated a second program for mobile devices compressed in MPEG-4 H.264 AVC for video and AAC -LC for audio, mainly known as 1seg . MPEG-2 is one of the three supported video coding formats supported by Blu-ray Disc. Early Blu-ray releases typically used MPEG-2 video, but recent releases are almost always in H.264 or occasionally VC-1 . Only MPEG-2 video (MPEG-2 part 2)

8632-564: The much larger LaserDisc (LD). By 2007, 200 billion CDs (including audio CDs, CD-ROMs and CD-Rs) had been sold worldwide. Standard CDs have a diameter of 120 mm (4.7 in), and are designed to hold up to 74 minutes of uncompressed stereo digital audio or about 650   MiB ( 681,574,400  bytes) of data. Capacity is routinely extended to 80 minutes and 700  MiB ( 734,003,200  bytes), 90 minutes 800  MiB ( 838,860,800  bytes), or 99 minutes 870  MiB ( 912,261,120  bytes) by arranging data more closely on

8736-536: The polycarbonate plastic and aluminium found in CDs. The data integrity of compact discs can be measured using surface error scanning , which can measure the rates of different types of data errors, known as C1 , C2 , CU and extended (finer-grain) error measurements known as E11 , E12 , E21 , E22 , E31 and E32 , of which higher rates indicate a possibly damaged or unclean data surface, low media quality, deteriorating media and recordable media written to by

8840-543: The raw data stored on the disc. These encoding techniques (defined in the Red Book ) were originally designed for CD Digital Audio , but they later became a standard for almost all CD formats (such as CD-ROM ). CDs are susceptible to damage during handling and from environmental exposure. Pits are much closer to the label side of a disc, enabling defects and contaminants on the clear side to be out of focus during playback. Consequently, CDs are more likely to suffer damage on

8944-423: The registration authority for MPEG-2 format identifiers. The registration descriptor of MPEG-2 transport is provided by ISO/IEC 13818-1 in order to enable users of the standard to unambiguously carry data when its format is not necessarily a recognized international standard. This provision will permit the MPEG-2 transport standard to carry all types of data while providing for a method of unambiguous identification of

9048-658: The rest of the world only has access to dwindling new stock from vendors on sites such as eBay or Amazon. TEAC & TASCAM continued to manufacture MiniDisc decks up until 2020 while Sony ceased production of hardware in 2013. Pinnacle Micro was a major manufacturer of magneto-optical drives. 3.5" drives were 128 MB and 230 MB. 5.25" drives produced were 650 MB and 1.3 GB (Sierra), 2.6 GB (Vertex) and 4.6 GB (Apex). The Vertex and Apex were non-ISO standard drives and used proprietary media. Pinnacle Micro has ceased production of these products. LMSI produced 5.25" magneto-optical drives as well. Maxoptix,

9152-425: The same basic principle as a standard magneto-optical drive: the write surface is heated up and took on a magnetic force applied from outside. But instead of using a magnetic head in the drive to make the changes, the magnets were built into the disk itself. The LIMDOW disk has two magnetic layers just behind the reflective writing surface. This write surface can take magnetism from one of those magnetic layers when it

9256-432: The same physical geometry as CD, and most DVD and Blu-ray players are backward compatible with audio CDs. CD sales in the United States peaked by 2000. By the early 2000s, the CD player had largely replaced the audio cassette player as standard equipment in new automobiles, with 2010 being the final model year for any car in the United States to have a factory-equipped cassette player. Two new formats were marketed in

9360-488: The same-sized disc. The Mini CD has various diameters ranging from 60 to 80 millimetres (2.4 to 3.1 in); they have been used for CD singles or delivering device drivers . The CD gained rapid popularity in the 1990s, quickly outselling all other audio formats in the United States by 1991, ending the market dominance of the phonograph record and the cassette tape . By 2000, the CD accounted for 92.3% of

9464-460: The sampling rates defined in MPEG-1 (32, 44.1 and 48 kHz). MPEG-2 Part 7 (ISO/IEC 13818-7), titled Advanced Audio Coding (AAC) specifies a rather different, non-backwards-compatible audio format. This format is most commonly called Advanced Audio Coding (AAC), but was originally called MPEG-2 NBC (non-backwards-compatible). AAC is more efficient than the previous MPEG audio standards, and

9568-566: The shortcomings of MPEG-1. MPEG-1's known weaknesses: Sakae Okubo of NTT was the ITU-T coordinator for developing the H.262/MPEG-2 Part 2 video coding standard and the requirements chairman in MPEG for the MPEG-2 set of standards. The majority of patents underlying MPEG-2 technology are owned by three companies: Sony (311 patents), Thomson (198 patents) and Mitsubishi Electric (119 patents). Hyundai Electronics (now SK Hynix ) developed

9672-575: The size of full-height 130 mm hard-drives (like in the IBM PC XT ). 130 mm media looks similar to a CD-ROM enclosed in an old-style caddy , while 90 mm media is about the size of a regular 3 1 ⁄ 2 -inch floppy disk , but twice the thickness. The cases provide dust resistance, and the drives themselves have slots constructed in such a way that they always appear to be closed. Original MO systems were WORM (write once, read many), and later systems were read/write. The disc consists of

9776-511: The standard in 1996. Philips coined the term compact disc in line with another audio product, the Compact Cassette , and contributed the general manufacturing process , based on video LaserDisc technology. Philips also contributed eight-to-fourteen modulation (EFM), while Sony contributed the error-correction method, CIRC, which offers resilience to defects such as scratches and fingerprints. The Compact Disc Story , told by

9880-541: The time) high storage capacity were required. The optical libraries could also manually be used on a Windows 2000/XP machine by selecting and ejecting discs under the Computer Management icon's Removable Storage Service, but this is cumbersome in practice. Light Intensity Modulated Direct OverWrite (LIMDOW) technology used a different write technology, which improved on the performance levels of earlier magneto-optical devices. LIMDOW disks and drives worked on

9984-420: The windings (the pitch ) is 1.6 μm (measured center-to-center, not between the edges). When playing an audio CD, a motor within the CD player spins the disc to a scanning velocity of 1.2–1.4 m/s ( constant linear velocity , CLV)—equivalent to approximately 500 RPM at the inside of the disc, and approximately 200 RPM at the outside edge. The track on the CD begins at the inside and spirals outward so

10088-468: Was an early device that used light for both recording and playback of sound signals on a transparent photograph . More than thirty years later, American inventor James T. Russell has been credited with inventing the first system to record digital media on a photosensitive plate. Russell's patent application was filed in 1966, and he was granted a patent in 1970. Following litigation, Sony and Philips licensed Russell's patents for recording in 1988. It

10192-501: Was chosen because it is half the vertical and half the horizontal resolution of the NTSC video. 352×288 is a similarly one-quarter PAL/SECAM resolution. This approximates the (overall) resolution of an analog VHS tape, which, although it has double the number of (vertical) scan lines, has a much lower horizontal resolution. MPEG-2 MPEG-2 (a.k.a. H.222/H.262 as was defined by the ITU )

10296-611: Was co-developed by Philips and Sony to store and play digital audio recordings. It uses the Compact Disc Digital Audio format which typically provides 74 minutes of audio on a disc. In later years, the compact disc was adapted for non-audio computer data storage purposes as CD-ROM and its derivatives. First released in Japan in October 1982, the CD was the second optical disc technology to be invented, after

10400-464: Was easily made. Sony first publicly demonstrated an optical digital audio disc in September 1976. A year later, in September 1977, Sony showed the press a 30 cm (12 in) disc that could play an hour of digital audio (44,100 Hz sampling rate and 16-bit resolution) using modified frequency modulation encoding. In September 1978, the company demonstrated an optical digital audio disc with

10504-483: Was introduced for 90 mm discs eliminating the initial erase pass when writing. This requires special media. By default, magneto-optical drives verify information after writing it to the disc, and are able to immediately report any problems to the operating system. This means writing can actually take three times longer than reading, but it makes the media extremely reliable, unlike the CD-R or DVD-R media upon which data

10608-458: Was published on 1 March 1979. A week later, on 8 March, Philips publicly demonstrated a prototype of an optical digital audio disc at a press conference called "Philips Introduce Compact Disc" in Eindhoven , Netherlands. Sony executive Norio Ohga , later CEO and chairman of Sony, and Heitaro Nakajima were convinced of the format's commercial potential and pushed further development despite widespread skepticism. In 1979, Sony and Philips set up

10712-581: Was the 90 mm drives), the 130 mm drives had some lasting service in corporate storage and retrieval. Optical libraries, such as the Hewlett Packard 40XT, were created to automate loading and storing of the disks. A self-contained unit holding 16 or more disks and connected by SCSI to a host computer, the library required specialized archival software to store indices of data, and select disks. Popular uses were for legal document storage and medical imaging, where high reliability, long life, and (at

10816-577: Was the second of several standards developed by the Moving Pictures Expert Group ( MPEG ) and is an international standard ( ISO / IEC 13818 , titled Information technology — Generic coding of moving pictures and associated audio information ). Parts 1 and 2 of MPEG-2 were developed in a collaboration with ITU-T , and they have a respective catalog number in the ITU-T Recommendation Series. While MPEG-2

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