Compact_disc

qas: question: When did Audio CDs become available for purchase?
answers: text: 1982
is_impossible: no

question: What does CD stand for?
answers: text: Compact Disc
is_impossible: no

question: What were CD's originally created to store?
answers: text: sound recordings
is_impossible: no

question: What does SVCD stand for?
answers: text: Super Video Compact Disc
is_impossible: no

question: In what year were compact discs realesed for purchase?
answers: text: 1982
is_impossible: no

question: What was the original intended format for CDs?
answers: text: data storage
is_impossible: no

question: What year were CDs changed so that they could store data?
is_impossible: yes

question: What does ROM in CD-ROM stand for?
is_impossible: yes

question: Which was released first; CD-R or CD-RW?
is_impossible: yes

question: Who created the CD?
is_impossible: yes

question: What does CD-i stand for?
is_impossible: yes

question: Who created Photo CDs?
is_impossible: yes

question: Which artist was the first to have their full catalogue converted to CD?
is_impossible: yes

question: What is liquid is applied to the blank CD?
is_impossible: yes
context: Compact Disc (CD) is a digital optical disc data storage format. The format was originally developed to store and play only sound recordings but was later adapted for storage of data (CD-ROM). Several other formats were further derived from these, including write-once audio and data storage (CD-R), rewritable media (CD-RW), Video Compact Disc (VCD), Super Video Compact Disc (SVCD), Photo CD, PictureCD, CD-i, and Enhanced Music CD. Audio CDs and audio CD players have been commercially available since October 1982.

qas: question: In what year were digital and physical music sales the same?
answers: text: 2014
is_impossible: no

question: How many CDs had been distrubuted worldwide by 2007?
answers: text: 200 billion
is_impossible: no

question: What percent decrease did audio CD sales experience?
answers: text: 50%
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question: How many CDs had been distrubuted around the world by 2007?
answers: text: 200 billion
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question: In 2004 how many CDs had been sold around the world?
answers: text: 30 billion
is_impossible: no

question: What year did digital media begin to replace CDs?
is_impossible: yes

question: How many CDs had been sold in the US by 2007?
is_impossible: yes

question: In what year did CD sales peak?
is_impossible: yes

question: Why are CD sales doing better than digital storage services?
is_impossible: yes

question: How have CD sales changed internationally?
is_impossible: yes

question: Why is the CD-RW more expensive than the ReWritable CD?
is_impossible: yes

question: What year was the digital audio disc released?
is_impossible: yes

question: How many CDs were mass produced in 1988?
is_impossible: yes
context: In 2004, worldwide sales of audio CDs, CD-ROMs and CD-Rs reached about 30 billion discs. By 2007, 200 billion CDs had been sold worldwide. CDs are increasingly being replaced by other forms of digital storage and distribution, with the result that audio CD sales rates in the U.S. have dropped about 50% from their peak; however, they remain one of the primary distribution methods for the music industry. In 2014, revenues from digital music services matched those from physical format sales for the first time.

qas: question: Who created Compact Disc prototypes in the 1970s?
answers: text: Philips and Sony
is_impossible: no

question: How lond did the creation of Red Book CD-DA standard take?
answers: text: a year
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question: How many CD players were sold in the United States in their first year?
answers: text: 400,000
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question: What did the CD evolve from?
answers: text: LaserDisc
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question: What made it possible for CDs to be played on any companies CD player?
answers: text: unified design
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question: To what does the compact disc owe its prosperity?
answers: text: cooperation between Philips and Sony
is_impossible: no

question: What year did CD players become available for purchase?
answers: text: 1982
is_impossible: no

question: Which company created the CD first?
is_impossible: yes

question: How many CD players sold in 1984?
is_impossible: yes

question: What year was the LaserDisc created?
is_impossible: yes

question: How long was the Red Book CD-DA in print?
is_impossible: yes

question: How were customers disadvantaged by the Philips and Sony merger?
is_impossible: yes

question: What does DRM stand for?
is_impossible: yes

question: What year was the digital rights management published?
is_impossible: yes

question: What is the PCM for an MP3 mono sound chanel?
is_impossible: yes
context: 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. Prototypes were developed by Philips and Sony independently in the late 1970s. In 1979, Sony and Philips set up a joint task force of engineers to design 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. The success of the compact disc has been credited to the cooperation between Philips and Sony, who came together to agree upon and develop 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.

qas: question: In what year did Philips institute a laboratory to create a digital audio disc?
answers: text: 1977
is_impossible: no

question: What was the proposed diameter for the original compact disc?
answers: text: 11.5 cm
is_impossible: no

question: What year did Philips propse the idea of a digital audio format?
answers: text: 1974
is_impossible: no

question: Who was the director of the Philips audio division in 1974?
answers: text: L. Ottens
is_impossible: no

question: What Philips engineer recommended a digital format?
is_impossible: yes

question: What was the 20cm diameter based on?
is_impossible: yes

question: What year was the digital audio disc released?
is_impossible: yes

question: How many engineer recommended the 11.5 cm diameter?
is_impossible: yes

question: Who was the director of Philips by 1977?
is_impossible: yes

question: When did Apple place MP3s on the market?
is_impossible: yes

question: Where is polycarbonate plastic created?
is_impossible: yes

question: What portion of music sales did CDs and DVDs account for in the United States as of 2012?
is_impossible: yes
context: In 1974, L. Ottens, director of the audio division of Philips, started a small group with the aim to develop an analog optical audio disc with a diameter of 20 cm 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, the diagonal of an audio cassette.

qas: question: Where was the 62nd AES Convention held?
answers: text: Brussels
is_impossible: no

question: Who was the general manger of Sony's audio department in 1971?
answers: text: Heitaro Nakajima
is_impossible: no

question: What year did Sony first exhibit the use of an optical digital audio disc?
answers: text: 1976
is_impossible: no

question: Where was the Philips Introduce Compact disc conference held?
answers: text: Eindhoven, Netherlands
is_impossible: no

question: What did Nakajima's team use to create a digital PCM adaptor audio tape recorder?
answers: text: Betamax video recorder
is_impossible: no

question: When did Sony release it's AES technical paper?
answers: text: 1 March 1979
is_impossible: no

question: What Japanese city is NHK located in?
is_impossible: yes

question: Who was Sony's general manager in 1970?
is_impossible: yes

question: When was the Betamax video recorder created?
is_impossible: yes

question: How many minutes could Sony's 1976 optical digital disk play?
is_impossible: yes

question: What was the sampling rate of Philips' 1979 optical digital dic?
is_impossible: yes

question: What is the priciest component of a CD?
is_impossible: yes

question: What has caused a decrease in CD sales?
is_impossible: yes

question: How many studio albums did David Bowie release in February 1985?
is_impossible: yes
context: 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. His team developed a digital PCM adaptor audio tape recorder using a Betamax video recorder in 1973. After this, in 1974 the leap to storing digital audio on an optical disc 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 disc that could play 60 minutes of digital audio (44,100 Hz sampling rate and 16-bit resolution) using MFM modulation. In September 1978, the company demonstrated an optical digital audio disc with a 150-minute playing time, 44,056 Hz sampling rate, 16-bit linear resolution, and cross-interleaved 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 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.

qas: question: In what year did Sony and Philips band together to design a new digital audio disc?
answers: text: 1979
is_impossible: no

question: What year was the Red Book CD-DA standard released?
answers: text: 1980
is_impossible: no

question: When did the IEC isntigate the Red Book CD-DA as an international standard?
answers: text: 1987
is_impossible: no

question: Who headed the 1979 Sony and Philips digital audio disc task force?
answers: text: Kees Schouhamer Immink and Toshitada Doi
is_impossible: no

question: Which company did Kees Schouhamer Immink work for?
is_impossible: yes

question: What did the team create five years after joining?
is_impossible: yes

question: What does IEC stand for?
is_impossible: yes

question: Who wrote the amendments in 1996?
is_impossible: yes

question: What did CD-DA stand for?
is_impossible: yes

question: What is the clear blank side made out of?
is_impossible: yes

question: What does SCMS stand for?
is_impossible: yes

question: In what year did Philips institute a laboratory to create a digital audio disc?
is_impossible: yes
context: As a result, in 1979, Sony and Philips set up 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 the standard in 1996.

qas: question: Who first sold a million copies on CD?
answers: text: Dire Straits
is_impossible: no

question: Which artist was the first to have their full catalogue converted to CD?
answers: text: David Bowie
is_impossible: no

question: What year was the Dire Straits album Brothers in Arms released?
answers: text: 1985
is_impossible: no

question: How many CDs were mass produced in 1988?
answers: text: 400 million
is_impossible: no

question: How many studio albums did David Bowie release in February 1985?
answers: text: 15
is_impossible: no

question: What is used to apply the reflecting layer to the clear layer?
is_impossible: yes

question: Why were successive formats less expensive than their predecessors?
is_impossible: yes

question: How many images could Photo CDs initially contain?
is_impossible: yes
context: The Japanese launch was followed in March 1983 by the introduction of CD players and discs to Europe and North America (where CBS Records released sixteen titles). This event is often seen as the "Big Bang" of the digital audio revolution. The new audio disc 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 the introduction of the portable Walkman the CD began to gain popularity in the larger popular and rock music markets. The first artist to sell a million copies on CD was Dire Straits, with their 1985 album Brothers in Arms. The first major artist to have his entire catalogue converted to CD was David Bowie, whose 15 studio albums were made available by RCA Records in February 1985, along with four greatest hits albums. In 1988, 400 million CDs were manufactured by 50 pressing plants around the world.

qas: question: What does ROM stand for?
answers: text: read-only memory
is_impossible: no

question: What year did Sony and Philips release CD-Recordable?
answers: text: 1990
is_impossible: no

question: What year was the 73rd AES Convention?
answers: text: 1983
is_impossible: no

question: What was the CDs predecessor?
answers: text: gramophone record
is_impossible: no

question: When was the gramophone released?
is_impossible: yes

question: What was the problem with recordable CDs?
is_impossible: yes

question: When was the DVD first released?
is_impossible: yes

question: Who created the DVD and Blu-ray discs?
is_impossible: yes

question: Who created the gramophone?
is_impossible: yes

question: Why are CD-G players not useful for karaoke?
is_impossible: yes

question: What wavelenght is used to pull data from a CD?
is_impossible: yes

question: Why does disc rot allow CD-Rs to last for years?
is_impossible: yes
context: The CD was planned to be the successor of the gramophone record for playing music, rather than primarily as a data storage medium. From its origins as a musical format, CDs have grown to encompass other applications. In 1983, following the CD's introduction, Immink and 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, CD-Recordable were introduced, also developed by both Sony and Philips. Recordable CDs were a new alternative to tape for recording music and copying music albums without defects introduced in compression used in other digital recording methods. Other newer video formats such as DVD and Blu-ray use the same physical geometry as CD, and most DVD and Blu-ray players are backward compatible with audio CD.

qas: question: What portion of music sales did CDs and DVDs account for in the United States as of 2012?
answers: text: 34 percent
is_impossible: no

question: Which country attributes over 80 percent of its music sales to physical formats?
answers: text: Japan
is_impossible: no

question: How are MP3s compressed?
answers: text: lossily-compressed
is_impossible: no

question: When did CD sales experience their original decline?
answers: text: 2000s
is_impossible: no

question: What has caused a decrease in CD sales?
answers: text: Internet-based distribution of files
is_impossible: no

question: In what year did CDs have an unusual spike in sales?
is_impossible: yes

question: What percentage of music sales do MP3s make up?
is_impossible: yes

question: How are CDs compressed?
is_impossible: yes

question: By what percentage have DIY and independent CDs increased?
is_impossible: yes

question: When did MP3 sales take off in Japan?
is_impossible: yes

question: When was the Beige Book published?
is_impossible: yes

question: What type of environment is best for a CD-R?
is_impossible: yes

question: How many engineer recommended the 11.5 cm diameter?
is_impossible: yes
context: Meanwhile, with the advent and popularity of Internet-based distribution of files in lossily-compressed audio formats such as MP3, sales of CDs began to decline in the 2000s. For example, between 2000 - 2008, despite overall growth in music sales and one anomalous year of increase, major-label CD sales declined overall by 20%, although independent and DIY music sales may be tracking better according to figures released 30 March 2009, and CDs still continue to sell greatly. As of 2012, CDs and DVDs made up only 34 percent of music sales in the United States. In Japan, however, over 80 percent of music was bought on CDs and other physical formats as of 2015.

qas: question: How are CDs mass produced?
answers: text: hydraulic press
is_impossible: no

question: What type of material is used to make CDs?
answers: text: raw polycarbonate plastic
is_impossible: no

question: What size is the diameter of the center hole in a CD?
answers: text: 15 mm
is_impossible: no

question: How long does it take to stamp out one CD?
answers: text: two to three seconds
is_impossible: no

question: What is the term for the center hole in a CD?
answers: text: stacking ring
is_impossible: no

question: How large is the screw that forces the plastic into the cavity?
is_impossible: yes

question: How long does it take the plastic to cool?
is_impossible: yes

question: What is the robotic arm called?
is_impossible: yes

question: What is a hydraulic press made out of?
is_impossible: yes

question: What closes the mold?
is_impossible: yes

question: What is the clear blank side made out of?
is_impossible: yes

question: Why is the CD-RW more expensive than the ReWritable CD?
is_impossible: yes

question: How are scratches on a CD fixed?
is_impossible: yes
context: Replicated CDs are mass-produced initially using a hydraulic press. Small granules of heated raw polycarbonate plastic are fed into the press. A screw forces the liquefied plastic into the mold cavity. The mold closes with a metal stamper in contact with the disc surface. The plastic is allowed to cool and harden. Once opened, the disc substrate is removed from the mold by a robotic arm, and a 15 mm diameter center hole (called a stacking ring) is created. The time it takes to "stamp" one CD is usually two to three seconds.

qas: question: What materials can be used to make the reflective layer on a CD?
answers: text: usually aluminium, but sometimes gold or other metal
is_impossible: no

question: What type of light is used to cure CDs?
answers: text: UV
is_impossible: no

question: What is a glass master?
answers: text: positive image of the desired CD surface
is_impossible: no

question: How are glass masters created?
answers: text: high-powered laser
is_impossible: no

question: What is the clear blank side made out of?
is_impossible: yes

question: What is used to apply the reflecting layer to the clear layer?
is_impossible: yes

question: How is a CD writer made?
is_impossible: yes

question: How is a positive image made of the CD made?
is_impossible: yes

question: How are the pits and lands made?
is_impossible: yes

question: Who was the director of Philips by 1977?
is_impossible: yes

question: Who was the director of the Philips audio division in 1974?
is_impossible: yes

question: When was the Kodak Picture CD released?
is_impossible: yes
context: This method produces the clear plastic blank part of the disc. After a metallic reflecting layer (usually aluminium, but sometimes gold or other metal) is applied to the clear blank substrate, the disc goes under a UV light for curing and it is ready to go to press. To prepare to press a CD, a glass master is made, using a high-powered laser on a device similar to a CD writer. The glass master is a positive image of the desired CD surface (with the desired microscopic pits and lands). After testing, it is used to make a die by pressing it against a metal disc.

qas: question: What is the term for a negative image of the glass master?
answers: text: die
is_impossible: no

question: How is the positive image on a CD protected? 
answers: text: lacquer
is_impossible: no

question: How is lacquer distrubted on a CD?
answers: text: rapid spinning
is_impossible: no

question: What is the name of the positive image?
is_impossible: yes

question: What is liquid is applied to the blank CD?
is_impossible: yes

question: How much edge protection lacquer is needed for the finished disc?
is_impossible: yes

question: How is the physical image placed on the blank CD?
is_impossible: yes

question: Why is the CD-RW more expensive than the ReWritable CD?
is_impossible: yes

question: Which ReWriteable CD is most common?
is_impossible: yes

question: How many CDs had been distrubuted worldwide by 2007?
is_impossible: yes
context: The die is a negative image of the glass master: typically, several are made, depending on the number of pressing mills that are to make the CD. The die then goes into a press, and the physical image is transferred to the blank CD, leaving a final positive image on the disc. A small amount of lacquer is applied as a ring around the center of the disc, and rapid spinning spreads it evenly over the surface. Edge protection lacquer is applied before the disc is finished. The disc can then be printed and packed.

qas: question: What is the priciest component of a CD?
answers: text: jewel case
is_impossible: no

question: Why did the cost of audio music increase when the production costs decreased?
answers: text: value increased
is_impossible: no

question: What did CDs retail for in 1995?
answers: text: $16.98
is_impossible: no

question: Who received the most profit from the sale of CDs?
answers: text: the store
is_impossible: no

question: How much did a jewel case cost in 1995?
answers: text: 30 cents
is_impossible: no

question: Why were successive formats less expensive than their predecessors?
is_impossible: yes

question: When did Apple place MP3s on the market?
is_impossible: yes

question: What was the wholesale cost of a cassette tape?
is_impossible: yes

question: What was the most expensive part of an MP3?
is_impossible: yes

question: What percentage of an MP3 does Apple receive?
is_impossible: yes

question: What royalties does a CD-RW have?
is_impossible: yes

question: What Philips engineer recommended a digital format?
is_impossible: yes

question: How were customers disadvantaged by the Philips and Sony merger?
is_impossible: yes
context: The most expensive part of a CD is the jewel case. In 1995, material costs were 30 cents for the jewel case and 10 to 15 cents for the CD. Wholesale cost of CDs was $0.75 to $1.15, which retailed for $16.98. On average, the store received 35 percent of the retail price, the record company 27 percent, the artist 16 percent, the manufacturer 13 percent, and the distributor 9 percent. When 8-track tapes, cassette tapes, and CDs were introduced, each was marketed at a higher price than the format they succeeded, even though the cost to produce the media was reduced. This was done because the apparent value increased. This continued from vinyl to CDs but was broken when Apple marketed MP3s for $0.99, and albums for $9.99. The incremental cost, though, to produce an MP3 is very small.

qas: question: How long are CDs expected to last?
answers: text: 20 to 100 years
is_impossible: no

question: What can cause sudden disc degradation?
answers: text: disc rot
is_impossible: no

question: Are CDs meant for permanent or temporary use?
answers: text: permanent
is_impossible: no

question: What can the aluminium on a disc cause reading errors?
is_impossible: yes

question: Why does disc rot allow CD-Rs to last for years?
is_impossible: yes

question: Why are CD-Rs considered temporary?
is_impossible: yes

question: What company discovered disc rot?
is_impossible: yes

question: What type of environment is best for a CD-R?
is_impossible: yes

question: How long does it take the plastic to cool?
is_impossible: yes

question: In what year did Sony and Philips band together to design a new digital audio disc?
is_impossible: yes

question: In what year did CD sales peak?
is_impossible: yes
context: CD-R recordings are designed to be permanent. Over time, the dye's physical characteristics may change causing read errors and data loss until the reading device cannot recover with error correction methods. The design life is from 20 to 100 years, depending on the quality of the discs, the quality of the writing drive, and storage conditions. However, testing has demonstrated such degradation of some discs in as little as 18 months under normal storage conditions. This failure is known as disc rot, for which there are several, mostly environmental, reasons.

qas: question: What does SCMS stand for?
answers: text: Serial Copy Management System
is_impossible: no

question: What does DRM stand for?
answers: text: digital rights management
is_impossible: no

question: What does AHRA stand for?
answers: text: Audio Home Recording Act
is_impossible: no

question: What type of CD is intended to be used in a Consumer audio CD Recorder?
answers: text: ReWritable Audio CD
is_impossible: no

question: Which is less expensive, the ReWritable Audio CD or a CD-RW?
answers: text: CD-RW
is_impossible: no

question: What plays standard CD-RW discs without changes?
is_impossible: yes

question: What royalties does a CD-RW have?
is_impossible: yes

question: What year was the digital rights management published?
is_impossible: yes

question: What is the international standard for home recordings?
is_impossible: yes

question: Why is the CD-RW more expensive than the ReWritable CD?
is_impossible: yes

question: When was the Beige Book published?
is_impossible: yes

question: When was the Betamax video recorder created?
is_impossible: yes

question: Who headed the 1979 Sony and Philips digital audio disc task force?
is_impossible: yes
context: The ReWritable Audio CD is designed to be used in a consumer audio CD recorder, which will not (without modification) accept standard CD-RW discs. These consumer audio CD recorders use the Serial Copy Management System (SCMS), an early form of digital rights management (DRM), to conform to the United States' Audio Home Recording Act (AHRA). The ReWritable Audio CD is typically somewhat more expensive than CD-RW due to (a) lower volume and (b) a 3% AHRA royalty used to compensate the music industry for the making of a copy.

qas: question: How fast could the first ReWritable CD be written?
answers: text: 4x speed
is_impossible: no

question: Which CD has writing speeds betwen 4x and 12x?
answers: text: High Speed ReWritable CD
is_impossible: no

question: How fast can Ultra Speed+ CDs write?
answers: text: 32x
is_impossible: no

question: How fast can Ultra Speed CDs write?
answers: text: 16x to 24x
is_impossible: no

question: What has only a 1x write speed?
is_impossible: yes

question: Which type of CD-RW cannot be read on a CD drive?
is_impossible: yes

question: Does a High Speed CD-RW drive write faster on ReWriteable CDs or High Speed ReWritable CDs?
is_impossible: yes

question: Which ReWriteable CD is most common?
is_impossible: yes

question: Why was the original ReWriteable CD written only at speeds faster than 4x?
is_impossible: yes

question: Where does the fungus Geotrichum candidum originate from?
is_impossible: yes

question: What type of light is used to cure CDs?
is_impossible: yes

question: What was the original intended format for CDs?
is_impossible: yes
context: Due to technical limitations, the original ReWritable CD could be written no faster than 4x speed. High Speed ReWritable CD has a different design, which permits writing at speeds ranging from 4x to 12x. Original CD-RW drives can only write to original ReWritable CDs. High Speed CD-RW drives can typically write to both original ReWritable CDs and High Speed ReWritable CDs. Both types of CD-RW discs can be read in most CD drives. Higher speed CD-RW discs, Ultra Speed (16x to 24x write speed) and Ultra Speed+ (32x write speed) are now available.

qas: question: Where is the semiconductor laser found in a CD player?
answers: text: on a swing arm
is_impossible: no

question: What wavelenght is used to pull data from a CD?
answers: text: 780 nm
is_impossible: no

question: In what pattern is data stored on a CD?
answers: text: spiral
is_impossible: no

question: What is used to discern the change of intensity in light on a CD?
answers: text: photodiode
is_impossible: no

question: What createds the change in light reflected off of a CD?
answers: text: change in height between pits and lands
is_impossible: no

question: How long is the swing arm?
is_impossible: yes

question: How many layers of polycarbonate are there?
is_impossible: yes

question: Why is the data arranged in a spiral pattern?
is_impossible: yes

question: Where is the photodiode?
is_impossible: yes

question: What does the width of a pit indicate?
is_impossible: yes

question: What year was the digital rights management published?
is_impossible: yes

question: How much video can a CD-R contain?
is_impossible: yes

question: What percentage of music sales do MP3s make up?
is_impossible: yes
context: A CD is read by focusing a 780 nm wavelength (near infrared) semiconductor laser housed within the CD player, through 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. By measuring the intensity change with a photodiode, the data can be read from the disc. In order to accommodate the spiral pattern of data, the semiconductor laser is placed on a swing arm within the disc tray of any CD player. This swing arm allows the laser to read information from the centre to the edge of a disc, without having to interrupt the spinning of the disc itself.

qas: question: What type of encoding do CDs implement?
answers: text: non-return-to-zero
is_impossible: no

question: Where can one find the encoding techniques for CDs?
answers: text: Red Book
is_impossible: no

question: What type of result from a CD will return a one?
answers: text: change from pit to land or land to pit
is_impossible: no

question: What type of modulation is implemented when a disc is mastered?
answers: text: eight-to-fourteen
is_impossible: no

question: How many ones are there between each zero?
is_impossible: yes

question: What decodes the eight-to-fourteen modulation?
is_impossible: yes

question: What is Reed-Solomon coding?
is_impossible: yes

question: Who designed the CD Digital Audio coding techniques?
is_impossible: yes

question: What does a land represent?
is_impossible: yes

question: Who created Compact Disc prototypes in the 1970s?
is_impossible: yes

question: How is the positive image on a CD protected? 
is_impossible: yes

question: What type of paper can Photo CD images be produced on?
is_impossible: yes
context: The pits and lands themselves do not directly represent the zeros and ones of binary data. Instead, non-return-to-zero, inverted encoding is used: a change from pit to land or land to pit indicates a one, while no change indicates a series of zeros. There must be at least two and no more than ten zeros between each one, 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 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).

qas: question: Where can one expect to find damage on a disc?
answers: text: label side of the disc
is_impossible: no

question: How are scratches on a CD fixed?
answers: text: refilling them with similar refractive plastic or by careful polishing
is_impossible: no

question: What eats at the plastic and aluminum found in CDs?
answers: text: fungus Geotrichum candidum
is_impossible: no

question: Where does the fungus Geotrichum candidum originate from?
answers: text: Belize
is_impossible: no

question: Where is polycarbonate plastic created?
is_impossible: yes

question: What are lands closer to?
is_impossible: yes

question: How are scratches on the labeled side of a disc fixed?
is_impossible: yes

question: What causes edges of CDs to be incorrectly sealed?
is_impossible: yes

question: Where is the metal reflective layer located?
is_impossible: yes

question: When was four-channel sound implemented?
is_impossible: yes

question: How many CDs had been distrubuted around the world by 2007?
is_impossible: yes

question: Where is the start of data on a CD?
is_impossible: yes
context: 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 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 corrode the metal reflective layer and to interfere with the focus of the laser on the pits. The fungus Geotrichum candidum, found in Belize, has been found to consume the polycarbonate plastic and aluminium found in CDs.

qas: question: Where is the start of data on a CD?
answers: text: the center
is_impossible: no

question: What size CD is most frequently used?
answers: text: 120 millimetres (4.7 in)
is_impossible: no

question: What is the size of a Mini CD?
answers: text: Eighty-millimeter
is_impossible: no

question: What is the size of a Maxi Single?
answers: text: 120 mm
is_impossible: no

question: Who was the Sony Executive in 1980?
answers: text: Norio Ohga
is_impossible: no

question: Who named the Maxi single?
is_impossible: yes

question: How many minutes does a Super Audio CD hold?
is_impossible: yes

question: When were Mini-CDs released?
is_impossible: yes

question: Why are CDs limited to one size?
is_impossible: yes

question: When was the London Philharmonic Orchestra's recording of the Ninth Symphony created?
is_impossible: yes

question: When was the Betamax video recorder created?
is_impossible: yes

question: Who created Photo CDs?
is_impossible: yes

question: Where is the metal reflective layer located?
is_impossible: yes
context: The digital data on a CD begins at the center of the disc and proceeds toward the edge, which allows adaptation to the different size formats available. Standard CDs are available in two sizes. By far, the most common is 120 millimetres (4.7 in) in diameter, with a 74- or 80-minute audio capacity and a 650 or 700 MiB (737,280,000-byte) data capacity. This capacity was reportedly specified by Sony executive Norio Ohga in May 1980 so as to be able to contain the entirety of the London Philharmonic Orchestra's recording of Beethoven's Ninth Symphony on one disc. This is a myth according to Kees Immink, as the code format had not yet been decided in May 1980. The adoption of EFM one month later would have allowed a playing time of 97 minutes for 120 mm diameter or 74 minutes for a disc as small as 100 mm. The 120 mm diameter has been adopted by subsequent formats, including Super Audio CD, DVD, HD DVD, and Blu-ray Disc. Eighty-millimeter discs ("Mini CDs") were originally designed for CD singles and can hold up to 24 minutes of music or 210 MiB of data but never became popular.[citation needed] Today, nearly every single is released on a 120 mm CD, called a Maxi single.[citation needed]

qas: question: Where does the Red Book get it's name from?
answers: text: the colour of its cover
is_impossible: no

question: What is the formal name for a CD? 
answers: text: Compact Disc Digital Audio
is_impossible: no

question: Do CDs have a two or four channel format?
answers: text: two-channel
is_impossible: no

question: What format has never been implemented on CDs?
answers: text: Four-channel sound
is_impossible: no

question: What was the sampling rate for the four-channel sound?
is_impossible: yes

question: When was four-channel sound implemented?
is_impossible: yes

question: What is the Red Book format for monaural audio?
is_impossible: yes

question: What is the official name of the Red Book?
is_impossible: yes

question: What is the PCM for an MP3 mono sound chanel?
is_impossible: yes

question: Why is the CD-RW more expensive than the ReWritable CD?
is_impossible: yes

question: Which company did Kees Schouhamer Immink work for?
is_impossible: yes

question: Why does disc rot allow CD-Rs to last for years?
is_impossible: yes
context: The logical format of an audio CD (officially Compact Disc Digital Audio or CD-DA) 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 colour 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 a Red Book CD; thus, mono source material is usually presented as two identical channels in a standard Red Book stereo track (i.e., mirrored mono); an MP3 CD, however, can have audio file formats with mono sound.

qas: question: What is the primary use of Compact Disc + Graphics?
answers: text: to display lyrics on a television set for karaoke
is_impossible: no

question: How is graphics information read from a CD+ Graphics?
answers: text: television set or a computer monitor
is_impossible: no

question: Which channels does the CD+G use to hold graphics data?
answers: text: channels R through W
is_impossible: no

question: Why can a CD+G not play on an audio CD player?
is_impossible: yes

question: How many bits does a normal CD use?
is_impossible: yes

question: Why are CD-G players not useful for karaoke?
is_impossible: yes

question: What channels does a normal CD use?
is_impossible: yes

question: When was the Compact Disc Digital Audio logo copyrighted?
is_impossible: yes

question: What type of encoding do CDs implement?
is_impossible: yes

question: When were Mini-CDs released?
is_impossible: yes
context: 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 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.

qas: question: How much video can a CD-R contain?
answers: text: 60 minutes
is_impossible: no

question: Which has better resolution, a VCD or SVCD?
answers: text: SVCD
is_impossible: no

question: How are lengthy videos fit onto SVCDs?
answers: text: lower the video bit rate
is_impossible: no

question: What is the maximum amount of video a SVCD can properly hold?
answers: text: 100 minutes
is_impossible: no

question: How much can a VCD hold?
is_impossible: yes

question: Why is there a video length limit on SVCD?
is_impossible: yes

question: What is the kilobit rate for a DVD?
is_impossible: yes

question: How does a VCN compare to a DVD?
is_impossible: yes

question: Why is it difficult to put more than 60 minutes on a DVD?
is_impossible: yes

question: What channels does a normal CD use?
is_impossible: yes

question: How is the positive image on a CD protected? 
is_impossible: yes

question: How many studio albums did David Bowie release in February 1985?
is_impossible: yes
context: SVCD has two-thirds the resolution of DVD, and over 2.7 times the resolution of VCD. One CD-R disc can hold up to 60 minutes of standard quality SVCD-format video. While no specific limit on SVCD video length is mandated by the specification, one must lower the video bit rate, and therefore quality, to accommodate very long videos. It is usually difficult to fit much more than 100 minutes of video onto one SVCD without incurring significant quality loss, and many hardware players are unable to play video with an instantaneous bit rate lower than 300 to 600 kilobits per second.

qas: question: Who created Photo CDs?
answers: text: Kodak
is_impossible: no

question: When were Photo CDs initially released?
answers: text: 1992
is_impossible: no

question: How many images could Photo CDs initially contain?
answers: text: 100
is_impossible: no

question: What type of paper can Photo CD images be produced on?
answers: text: photographic paper
is_impossible: no

question: In what book are Photo CD standards defined?
answers: text: Beige Book
is_impossible: no

question: When was the Beige Book published?
is_impossible: yes

question: How many photos does the CD-ROM XA hold?
is_impossible: yes

question: Who invented CD-i Players?
is_impossible: yes

question: Why can't Photo CDs work on any computer?
is_impossible: yes

question: When was the Kodak Picture CD released?
is_impossible: yes

question: Which channels does the CD+G use to hold graphics data?
is_impossible: yes

question: Do CDs have a two or four channel format?
is_impossible: yes

question: Who created Compact Disc prototypes in the 1970s?
is_impossible: yes
context: Photo CD is a system designed by Kodak for digitizing and storing photos on a CD. Launched in 1992, the discs were designed to hold nearly 100 high-quality images, scanned prints and slides using special proprietary encoding. Photo CDs are defined in the Beige Book and conform to the CD-ROM XA and CD-i Bridge specifications as well. They are intended to play on CD-i players, Photo CD players and any computer with the suitable software irrespective of the operating system. The images can also be printed out on photographic paper with a special Kodak machine. This format is not to be confused with Kodak Picture CD, which is a consumer product in CD-ROM format.

qas: question: When did record companies first attempt to protect their CDs from copying?
answers: text: 2001
is_impossible: no

question: Who said that protected CDs are not allowed to carry the CDDA logo?
answers: text: Philips
is_impossible: no

question: Where does the Red Book mention copy protection?
answers: text: in the subcode
is_impossible: no

question: When was the "anti-copy" subcode written in the Red Book?
is_impossible: yes

question: Who created the anti-protection systems software?
is_impossible: yes

question: When was the Compact Disc Digital Audio logo copyrighted?
is_impossible: yes

question: What devices do standard CDs not play on?
is_impossible: yes

question: Why does Philips want non-standard discs to have the trademarked logo?
is_impossible: yes

question: How have CD sales changed internationally?
is_impossible: yes

question: Where is the start of data on a CD?
is_impossible: yes

question: To what does the compact disc owe its prosperity?
is_impossible: yes
context: The Red Book audio specification, except for a simple "anti-copy" statement in the subcode, does not include any copy protection mechanism. Known at least as early as 2001, attempts were made by record companies to market "copy-protected" non-standard compact discs, which cannot be ripped, or copied, to hard drives or easily converted to MP3s. One major drawback to these copy-protected discs is that most will not play on either computer CD-ROM drives or some standalone CD players that use CD-ROM mechanisms. Philips has stated that such discs are not permitted to bear the trademarked Compact Disc Digital Audio logo because they violate the Red Book specifications. Numerous copy-protection systems have been countered by readily available, often free, software.