Editing Compact disc (section)

== Logical format ==
{{Unreferenced section|date=May 2018}}
=== Audio CD ===
[[File:CDP101a.jpg|thumb|[[Sony CDP-101]] from 1982, the first commercially released [[CD]] player for [[consumer]]s]]
[[File:CD player.jpg|thumb|Philips CD100 from 1983, the first commercially released CD player in the US and Europe]]
{{Main|Compact Disc Digital Audio}}
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.<ref>{{Cite web|title=IEC 60908:1999 {{!}} IEC Webstore|url=https://webstore.iec.ch/publication/3885|access-date=2020-07-09|website=webstore.iec.ch|archive-url=https://web.archive.org/web/20160506194944/https://webstore.iec.ch/publication/3885|archive-date=6 May 2016|url-status=live}}</ref> 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|44.1&nbsp;kHz]] [[sampling rate]] per channel. [[Four-channel Compact Disc Digital Audio|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, the mono source material is usually presented as two identical channels in a standard ''Red Book'' stereo track (i.e., [[mono sound#Mirrored mono|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 is stored either in the [[Optical disc authoring|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 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 the [[#CD + Graphics|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 ===
{{Main|Super Audio CD}}
Super Audio CD (SACD) is a high-resolution, read-only [[optical disc|optical]] [[audio storage|audio disc]] format that was designed to provide [[high fidelity|higher-fidelity]] digital audio reproduction than 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 is playable in standard CD players, thus making them backward compatible.

=== CD-MIDI ===
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''.

=== CD-ROM ===
{{Main|CD-ROM}}
For 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 ===
{{Main|Video CD}}
Video CD (VCD, View CD, and Compact Disc digital video) is a standard digital format for storing video media on 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, [[Panasonic|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 [[Source Input Format|SIF]]) resolution 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.

=== Super Video CD ===
{{Main|Super Video CD}}
Super Video CD (Super Video Compact Disc or SVCD) is a format used for storing video media on standard compact discs. SVCD was intended as a successor to VCD and an alternative to DVD-Video and falls somewhere between both in terms of technical capability and picture quality.

SVCD has two-thirds the [[display resolution|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 a significant quality loss, and many hardware players are unable to play a video with an instantaneous bit rate lower than 300 to 600 [[kilobit]]s per second.

=== Photo CD ===
{{Main|Photo CD}}
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 suitable software (irrespective of [[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.

=== CD-i ===
{{Main|Philips CD-i}}
The Philips ''[[Green Book (CD standard)|Green Book]]'' specifies a standard for interactive multimedia compact discs designed for [[CD-i]] players (1993). CD-i discs can contain audio tracks that can be played on regular [[CD player]]s, but CD-i discs are not compatible with most [[CD-ROM]] drives and software. The [[CD-i Ready]] specification was later created to improve compatibility with audio CD players, and the [[CD-i Bridge]] specification was added to create CD-i-compatible discs that can be accessed by regular CD-ROM drives.

=== CD-i Ready ===
{{Main|CD-i Ready}}
Philips defined a format similar to CD-i called [[CD-i Ready]], which puts CD-i software and data into the [[Pregap#Computer data in pregap|pregap]] of track 1. This format was supposed to be more compatible with older audio CD players.

=== Enhanced Music CD (CD+) ===
{{Main|Blue Book (CD standard)}}
Enhanced Music CD, also known as CD Extra or CD Plus, is a format that combines [[CD-DA|audio tracks]] and [[CD-ROM|data tracks]] on the same disc by putting audio tracks in a first [[Session (CD)|session]] and data in a second session. It was developed by Philips and Sony, and it is defined in the ''[[Blue Book (CD standard)|Blue Book]]''.

=== VinylDisc ===
{{Main|VinylDisc}}
VinylDisc is the hybrid of a standard audio CD and the [[Gramophone record|vinyl record]]. The vinyl layer on the disc's label side can hold approximately three minutes of music.