Compact disc - History

A compact disc (or CD) is an optical disc used to store digital data, originally developed for storing digital audio. It is the standard playback format for commercial audio recordings today. A standard compact disc, often known as an "audio CD" to differentiate it from later variants, stores audio data in a format compliant with the red book standard. An audio CD consists of several stereo tracks stored using 16-bit PCM coding at a sampling rate of 44.1 kHz. Standard compact discs have a diameter of 120 mm, th ...

Including:

• Compact disc - History
• Compact disc - Physical details
• Compact disc - Audio format
• Compact disc - Storage capacity
• Compact disc - Data structure
• Compact disc - Subcode
• Compact disc - CD-Text
• Compact disc - The AAD ADD DDD code for audio CDs
• Compact disc - CD-ROM
• Compact disc - Recordability
• Compact disc - Copy protection
• Compact disc - Non-standard CD behaviors
• Compact disc - Name

Read more here: » Compact disc: Encyclopedia - Compact disc

Many CDs, especially classical music and many popular recordings (especially on early CDs), come with a three letter code printed on the back, where "A" stands for analog and "D" stands for digital. The first letter represents how the album was recorded, the second how it was mixed, and the third how it was transferred (inevitably a D, as the CD is a digital medium). Almost all early CDs are "AAD" (analog recording and mixing, digital transfer to CD) as a result. Often this code was accompanied by a short description such as "Full Digit ...

See also:

Compact disc, Compact disc - History, Compact disc - Physical details, Compact disc - Audio format, Compact disc - Storage capacity, Compact disc - Data structure, Compact disc - Subcode, Compact disc - CD-Text, Compact disc - The AAD, ADD, DDD code for audio CDs, Compact disc - CD-ROM, Compact disc - Recordability, Compact disc - Copy protection, Compact disc - Non-standard CD behaviors, Compact disc - Name

Read more here: » Compact disc: Encyclopedia II - Compact disc - The AAD, ADD, DDD code for audio CDs

In the early 1970s, using video Laserdisc technology, Philips' researchers started experiments with "audio-only" optical discs, initially with wideband frequency modulation FM and later digitized PCM audio signals. At the end of the 1970s, Philips, Sony, and other companies presented prototypes of digital audio discs. In 1979 Philips and Sony decided to join forces, setting up a joint task force of engineers whose mission was to design the new digital audio disc. Prominent members of the task force were Kees Immink and Toshitada Doi. ...

See also:

Compact disc, Compact disc - History, Compact disc - Physical details, Compact disc - Manufacturing Process, Compact disc - Audio format, Compact disc - Storage capacity, Compact disc - Data structure, Compact disc - Subcode, Compact disc - CD-Text, Compact disc - The SPARS Code for audio CDs, Compact disc - Three-Letter Codes, Compact disc - CD-ROM, Compact disc - Recordability, Compact disc - Copy protection, Compact disc - Non-standard CD behaviors, Compact disc - Name

Read more here: » Compact disc: Encyclopedia II - Compact disc - History

In the early 1970s, using video Laserdisc technology, Philips' researchers started experiments with "audio-only" optical discs, initially with wideband frequency modulation FM and later digitized PCM audio signals. At the end of the 70s, Philips, Sony, and other companies presented prototypes of digital audio discs. In 1979 Philips and Sony decided to join forces, setting up a joint taskforce of engineers whose mission was to design the new digital audio disc. Prominent members of the taskforce were Kees Immink and Toshitada Doi. Afte ...

See also:

Compact disc, Compact disc - History, Compact disc - Physical details, Compact disc - Audio format, Compact disc - Storage capacity, Compact disc - Data structure, Compact disc - Subcode, Compact disc - CD-Text, Compact disc - The AAD ADD DDD code for audio CDs, Compact disc - CD-ROM, Compact disc - Recordability, Compact disc - Copy protection, Compact disc - Non-standard CD behaviors, Compact disc - Name

Read more here: » Compact disc: Encyclopedia II - Compact disc - History

Compact discs are made from a 1.2 mm thick disc of polycarbonate plastic coated with a much thinner layer of Super Purity Aluminium (or rarely, gold, used for its data longevity, such as in some limited-edition audiophile CDs) layer which is protected by a film of lacquer. The lacquer can be printed with a label. Common printing methods for compact discs are silkscreening and offset printing. CDs are available in two sizes. By far the most common is 120 mm in diameter, with a 74-minute audio capacity and a 650-MB data (See storage ...

See also:

Compact disc, Compact disc - History, Compact disc - Physical details, Compact disc - Audio format, Compact disc - Storage capacity, Compact disc - Data structure, Compact disc - Subcode, Compact disc - CD-Text, Compact disc - The AAD ADD DDD code for audio CDs, Compact disc - CD-ROM, Compact disc - Recordability, Compact disc - Copy protection, Compact disc - Non-standard CD behaviors, Compact disc - Name

Read more here: » Compact disc: Encyclopedia II - Compact disc - Physical details

Compact discs are made from a 1.2 mm thick disc of polycarbonate plastic coated with a much thinner layer of Super Purity Aluminium (or rarely, gold, used for its data longevity, such as in some limited-edition audiophile CDs) layer which is protected by a film of lacquer. The lacquer can be printed with a label. Common printing methods for compact discs are silkscreening and offset printing. CDs are available in two sizes. By far the most common is 120 mm in diameter, with a 74-minute audio capacity and a 650-MB data (See storage ...

See also:

Compact disc, Compact disc - History, Compact disc - Physical details, Compact disc - Manufacturing Process, Compact disc - Audio format, Compact disc - Storage capacity, Compact disc - Data structure, Compact disc - Subcode, Compact disc - CD-Text, Compact disc - The SPARS Code for audio CDs, Compact disc - Three-Letter Codes, Compact disc - CD-ROM, Compact disc - Recordability, Compact disc - Copy protection, Compact disc - Non-standard CD behaviors, Compact disc - Name

Read more here: » Compact disc: Encyclopedia II - Compact disc - Physical details

Mastering Process: First, in a clean room, a glass master is prepared by coating a perfectly flat piece of half inch thick circular glass with a layer of nickel. The nickel is transfered by exciting the nickel to a plasma state whereupon a thin layer of nickel will adhere to the glass. The glass is coated with an emulsion. Source material is encoded into the appropriate format whereupon a computer controlled machine "burns" the pits into the emulsion layer of the glass master. The glass master produced ...

See also:

Compact disc, Compact disc - History, Compact disc - Physical details, Compact disc - Manufacturing Process, Compact disc - Audio format, Compact disc - Storage capacity, Compact disc - Data structure, Compact disc - Subcode, Compact disc - CD-Text, Compact disc - The SPARS Code for audio CDs, Compact disc - Three-Letter Codes, Compact disc - CD-ROM, Compact disc - Recordability, Compact disc - Copy protection, Compact disc - Non-standard CD behaviors, Compact disc - Name

Read more here: » Compact disc: Encyclopedia II - Compact disc - Manufacturing Process

The Red Book audio specification does not include any copy protection mechanism. Ripping is the process by which the contents of an audio disc is copied out verbatim to a duplicate disc or re-encoded into some other format, such as MP3 or Ogg Vorbis. An error-correcting code is included with Red Book audio to deal with small scratches or defects on the disc media. Where error correction fails on larger defects, audio CD players are expected to apply interpolati ...

See also:

Compact disc, Compact disc - History, Compact disc - Physical details, Compact disc - Manufacturing Process, Compact disc - Audio format, Compact disc - Storage capacity, Compact disc - Data structure, Compact disc - Subcode, Compact disc - CD-Text, Compact disc - The SPARS Code for audio CDs, Compact disc - Three-Letter Codes, Compact disc - CD-ROM, Compact disc - Recordability, Compact disc - Copy protection, Compact disc - Non-standard CD behaviors, Compact disc - Name

Read more here: » Compact disc: Encyclopedia II - Compact disc - Copy protection

Some commercially released audio discs have a "secret" bonus track. These may be an extension of the last audio track or a separate track hidden from the disc's table of contents. Either way, the hidden portion is heard when the disc is played to the end. Other discs hide the extra material at the beginning of the disc. On most discs, the location of the first track listed in the table of contents immediately follows the table of contents itself. In this case, the hidden track is an unlisted track sandwiched between the two. To hear the hidden track, the listener must usually "rewind" the player past the beginn ...

See also:

Compact disc, Compact disc - History, Compact disc - Physical details, Compact disc - Manufacturing Process, Compact disc - Audio format, Compact disc - Storage capacity, Compact disc - Data structure, Compact disc - Subcode, Compact disc - CD-Text, Compact disc - The SPARS Code for audio CDs, Compact disc - Three-Letter Codes, Compact disc - CD-ROM, Compact disc - Recordability, Compact disc - Copy protection, Compact disc - Non-standard CD behaviors, Compact disc - Name

Read more here: » Compact disc: Encyclopedia II - Compact disc - Non-standard CD behaviors

Injection moulding is used to mass produce compact discs. A "stamper" is made from the original media (audio tape, data disc, etc.) by writing to a glass disc (referred to as a glass master) coated with a photosensitive dye with a laser. This dye is then etched, leaving the data track. It is then plated to make a positive version of the CD. Polycarbonate is liquified and injected into the mold cavity where the stamper transfers the pattern of pits and lands to the polycarbonate disc. The disc is the ...

See also:

Compact disc, Compact disc - History, Compact disc - Physical details, Compact disc - Manufacturing Process, Compact disc - Audio format, Compact disc - Storage capacity, Compact disc - Data structure, Compact disc - Subcode, Compact disc - CD-Text, Compact disc - The SPARS Code for audio CDs, Compact disc - Three-Letter Codes, Compact disc - CD-ROM, Compact disc - Recordability, Compact disc - Copy protection, Compact disc - Non-standard CD behaviors, Compact disc - Name

Read more here: » Compact disc: Encyclopedia II - Compact disc - Recordability

Main article: CD-ROM For its first few years of existence, the compact disc was purely an audio format. However, in 1985 Yellow Book CD-ROM standard was established by Sony and Philips, which defined a non-volatile optical data storage medium using the same physical format as audio compact discs, readable by a computer with a CD-ROM drive. ...

See also:

Compact disc, Compact disc - History, Compact disc - Physical details, Compact disc - Manufacturing Process, Compact disc - Audio format, Compact disc - Storage capacity, Compact disc - Data structure, Compact disc - Subcode, Compact disc - CD-Text, Compact disc - The SPARS Code for audio CDs, Compact disc - Three-Letter Codes, Compact disc - CD-ROM, Compact disc - Recordability, Compact disc - Copy protection, Compact disc - Non-standard CD behaviors, Compact disc - Name

Read more here: » Compact disc: Encyclopedia II - Compact disc - CD-ROM

Under a microscope, all that is visible is a series of various-sized pits arranged in a long spiral, starting near the inner hole. As bit-times are counted off, a transition (pit-to-land, or land-to-pit) is interpreted as a "1" bit, while a constant region (all-land or all-pit) is interpreted as a "0" bit. Each 14 consecutive bits are grouped and decoded using Eight-to-Fourteen Modulation to get a byte. Each 14-bit ...

See also:

Compact disc, Compact disc - History, Compact disc - Physical details, Compact disc - Manufacturing Process, Compact disc - Audio format, Compact disc - Storage capacity, Compact disc - Data structure, Compact disc - Subcode, Compact disc - CD-Text, Compact disc - The SPARS Code for audio CDs, Compact disc - Three-Letter Codes, Compact disc - CD-ROM, Compact disc - Recordability, Compact disc - Copy protection, Compact disc - Non-standard CD behaviors, Compact disc - Name

Read more here: » Compact disc: Encyclopedia II - Compact disc - Data structure

Many CDs, especially classical music and many popular recordings, come with a three-letter code printed on the back known as the SPARS (acronym for Society of Professional Audio Recording Studios) Code, where "A" stands for analog and "D" stands for digital. The first letter represents how the album was recorded, the second how it was mixed, and the third how it was transferred (inevitably a D, as the CD is a digital medium). Almost all early CDs are "AAD" (analog recording and mixing, digital transfer to CD) as a result. Often this code was accompanied by a short description such as "Full Digital Recor ...

See also:

Compact disc, Compact disc - History, Compact disc - Physical details, Compact disc - Manufacturing Process, Compact disc - Audio format, Compact disc - Storage capacity, Compact disc - Data structure, Compact disc - Subcode, Compact disc - CD-Text, Compact disc - The SPARS Code for audio CDs, Compact disc - Three-Letter Codes, Compact disc - CD-ROM, Compact disc - Recordability, Compact disc - Copy protection, Compact disc - Non-standard CD behaviors, Compact disc - Name

Read more here: » Compact disc: Encyclopedia II - Compact disc - The SPARS Code for audio CDs

The format of the audio disc, known as the "Red Book" / Sony standard, was laid out by Sony and Philips in 1981. Philips is responsible for the licensing program of the intellectual property pertinent to the Compact Disc including the "Compact Disc Digital Audio" logo that appears on the disc. In broad terms the format is a two-channel (four-channel sound is an allowed option within the Red Book format, but has never been implemented) stereo 16-bit PCM encoding at a 44.1 kHz sampling rate. Reed-Solomon error correction allows the CD to be scratched ...

See also:

Compact disc, Compact disc - History, Compact disc - Physical details, Compact disc - Manufacturing Process, Compact disc - Audio format, Compact disc - Storage capacity, Compact disc - Data structure, Compact disc - Subcode, Compact disc - CD-Text, Compact disc - The SPARS Code for audio CDs, Compact disc - Three-Letter Codes, Compact disc - CD-ROM, Compact disc - Recordability, Compact disc - Copy protection, Compact disc - Non-standard CD behaviors, Compact disc - Name

Read more here: » Compact disc: Encyclopedia II - Compact disc - Audio format

Many CDs, especially classical music and many popular recordings (especially on early CDs), come with a three letter code printed on the back, where "A" stands for analog and "D" stands for digital. The first letter represents how the album was recorded, the second how it was mixed, and the third how it was transferred (inevitably a D, as the CD is a digital medium). Almost all early CDs are "AAD" (analog recording and mixing, digital transfer to CD) as a result. Often this code was accompanied by a short description such as "Full Digital ...

See also:

Compact disc, Compact disc - History, Compact disc - Physical details, Compact disc - Audio format, Compact disc - Storage capacity, Compact disc - Data structure, Compact disc - Subcode, Compact disc - CD-Text, Compact disc - The AAD ADD DDD code for audio CDs, Compact disc - CD-ROM, Compact disc - Recordability, Compact disc - Copy protection, Compact disc - Non-standard CD behaviors, Compact disc - Name

Read more here: » Compact disc: Encyclopedia II - Compact disc - The AAD ADD DDD code for audio CDs

Injection moulding is used to mass produce compact discs. A "stamper" is made from the original media (audio tape, data disc, etc.) by writing to a glass disc (referred to as a glass master) coated with a photosensitive dye with a laser. This dye is then etched, leaving the data track. It is then plated to make a positive version of the CD. Polycarbonate is liquified and injected into the mold cavity where the stamper transfers the pattern of pits and lands to the polycarbonate disc. The disc is the ...

See also:

Compact disc, Compact disc - History, Compact disc - Physical details, Compact disc - Audio format, Compact disc - Storage capacity, Compact disc - Data structure, Compact disc - Subcode, Compact disc - CD-Text, Compact disc - The AAD ADD DDD code for audio CDs, Compact disc - CD-ROM, Compact disc - Recordability, Compact disc - Copy protection, Compact disc - Non-standard CD behaviors, Compact disc - Name

Read more here: » Compact disc: Encyclopedia II - Compact disc - Recordability

The Red Book audio specification does not include any copy protection mechanism. Ripping is the process by which the contents of an audio disc is copied out verbatim to a duplicate disc or re-encoded into some other format, such as MP3. An error-correcting code is included with Red Book audio to deal with small scratches or defects on the disc media. Where error correction fails on larger defects, audio CD players are expected to apply interpolati ...

See also:

Compact disc, Compact disc - History, Compact disc - Physical details, Compact disc - Audio format, Compact disc - Storage capacity, Compact disc - Data structure, Compact disc - Subcode, Compact disc - CD-Text, Compact disc - The AAD ADD DDD code for audio CDs, Compact disc - CD-ROM, Compact disc - Recordability, Compact disc - Copy protection, Compact disc - Non-standard CD behaviors, Compact disc - Name

Read more here: » Compact disc: Encyclopedia II - Compact disc - Copy protection

The smallest entity in the CD audio format is called a frame. A frame can accommodate six complete 16-bit stereo samples, i.e. 2×2×6 = 24 bytes. Data in a CD-ROM are organized in both frames and sectors. A CD-ROM sector contains 98 frames, and holds 98×24 = 2352 bytes. The CD-ROM is in essence a data disc, which cannot rely on error concealment, and it requires therefore a higher reliability of the retrieved data. In order to achieve improved error correction and detection, a CD-ROM has a t ...

See also:

Compact disc, Compact disc - History, Compact disc - Physical details, Compact disc - Audio format, Compact disc - Storage capacity, Compact disc - Data structure, Compact disc - Subcode, Compact disc - CD-Text, Compact disc - The AAD ADD DDD code for audio CDs, Compact disc - CD-ROM, Compact disc - Recordability, Compact disc - Copy protection, Compact disc - Non-standard CD behaviors, Compact disc - Name

Read more here: » Compact disc: Encyclopedia II - Compact disc - Data structure

The format of the audio disc, known as the "Red Book" / Sony standard, was laid out by Sony and Philips in 1981. Philips is responsible for the licensing program of the intellectual property pertinent to the Compact Disc including the "Compact Disc Digital Audio" logo that appears on the disc. In broad terms the format is a two-channel (four-channel sound is an allowed option within the Red Book format, but has never been implemented) stereo 16-bit PCM encoding at a 44.1 kHz sampling rate. Reed-Solomon error correction allows the CD to be scratched ...

See also:

Compact disc, Compact disc - History, Compact disc - Physical details, Compact disc - Audio format, Compact disc - Storage capacity, Compact disc - Data structure, Compact disc - Subcode, Compact disc - CD-Text, Compact disc - The AAD ADD DDD code for audio CDs, Compact disc - CD-ROM, Compact disc - Recordability, Compact disc - Copy protection, Compact disc - Non-standard CD behaviors, Compact disc - Name

Read more here: » Compact disc: Encyclopedia II - Compact disc - Audio format

Some commercially released audio discs have a "secret" bonus track. These may be an extension of the last audio track or a separate track hidden from the disc's table of contents. Either way, the hidden portion is heard when the disc is played to the end. Other discs hide the extra material at the beginning of the disc. On most discs, the location of the first track listed in the table of contents immediately follows the table of contents itself. In this case, the hidden track is an unlisted track sandwiched between the two. To hear the hidden track, the listener must usually "rewind" the player past the beginn ...

See also:

Compact disc, Compact disc - History, Compact disc - Physical details, Compact disc - Audio format, Compact disc - Storage capacity, Compact disc - Data structure, Compact disc - Subcode, Compact disc - CD-Text, Compact disc - The AAD ADD DDD code for audio CDs, Compact disc - CD-ROM, Compact disc - Recordability, Compact disc - Copy protection, Compact disc - Non-standard CD behaviors, Compact disc - Name

Read more here: » Compact disc: Encyclopedia II - Compact disc - Non-standard CD behaviors