A C2 error is a read error of a

Compact Disc The compact disc (CD) is a Digital media, digital optical disc data storage format co-developed by Philips and Sony to store and play digital audio recordings. It employs the Compact Disc Digital Audio (CD-DA) standard and was capable of hol ...

. C2 errors can to a degree be recovered by the hardware

error detection and correction In information theory and coding theory with applications in computer science and telecommunications, error detection and correction (EDAC) or error control are techniques that enable reliable delivery of digital data over unreliable communi ...

scheme. A CD drive can have extraction errors when the data on the disc is not readable due to scratches or smudges. The drive can compensate by supplying a "best guess" of what the missing data was, then supplying the missing data. C2 error correction is an analysis over many interleaved frames, an improvement over C1 error correction, which analyzed just one frame, resulting in more accurate data correction. C2 error correction codes are also used by the

Digital Audio Tape Digital Audio Tape (DAT or R-DAT) is a signal recording and playback medium developed by Sony and introduced in 1987. In appearance it is similar to a Compact Cassette, using 3.81 mm / 0.15" (commonly referred to as 4 mm) magnetic t ...

(DAT) format. C2 errors can cause problems for CD rippers when copying CD-Audio discs, and specialized software exists to overcome this problem, such as

Exact Audio Copy Exact Audio Copy (EAC) is a CD ripping program for Microsoft Windows. The program has been developed by Andre Wiethoff since 1998. Wiethoff's motivation for creating the program was that other such software only performed jitter correction whil ...

. Some

copy protection Copy protection, also known as content protection, copy prevention and copy restriction, is any measure to enforce copyright by preventing the reproduction of software, films, music, and other media. Copy protection is most commonly found on vid ...

schemes add false C2 errors to discs to discourage copying. While causing data loss on

Video CD Video CD (abbreviated as VCD, and also known as Compact Disc Digital Video), (not to be confused with CD Video which is a type of Laserdisc) is a home video format and the first format for distributing films on standard optical discs. The f ...

s (''Mode 2 Form 2'') and

Audio CD Compact Disc Digital Audio (CDDA or CD-DA), also known as Digital Audio Compact Disc or simply as Audio CD, is the standard format for audio compact discs. The standard is defined in the '' Red Book'' technical specifications, which is why t ...

s, individual C2 errors are correctable on data CDs (using ''Mode 1'' and ''Mode 2 Form 1'').

Measurement

C2 errors can be measured using surface error scanning, and are usually caused by scratches and dirt on the data surface, as well as media degradation. Error scanning functionality and support varies among vendors and models of

optical disc drive In computing, an optical disc drive (ODD) is a disc drive that uses laser light or electromagnetic waves within or near the visible light spectrum as part of the process of reading or writing data to or from optical discs. Some drives can on ...

References

Compact disc DVD Optical computer storage media {{compu-storage-stub

Measurement

See also

References