CD-Text is an extension of the Red Book

Compact Disc The compact disc (CD) is a digital optical disc data storage format that was co-developed by Philips and Sony to store and play digital audio recordings. In August 1982, the first compact disc was manufactured. It was then released in Oc ...

specifications standard for audio CDs. It allows storage of additional information (e.g. album name, song name, and artist name) on a standards-compliant audio CD. The specification for CD-Text was included in the Multi-Media Commands Set 3 R01 (MMC-3) standard, released in September 1996 and backed by

Sony , commonly stylized as SONY, is a Japanese multinational conglomerate corporation headquartered in Minato, Tokyo, Japan. As a major technology company, it operates as one of the world's largest manufacturers of consumer and professiona ...

. It was also added to new revisions of the Red Book. The actual text is stored in a format compatible with

Interactive Text Transmission System This is an incomplete list of standards published by the International Electrotechnical Commission (IEC). The numbers of older IEC standards were converted in 1997 by adding 60000; for example IEC 27 became IEC 60027. IEC standards often have m ...

(ITTS), defined in the IEC 61866 standard.IEC 61866:1997 Audiovisual systems – Interactive text transmission system (ITTS)
The ITTS standard is also applied in the MiniDisc format, as well as in

Digital Audio Broadcasting Digital radio is the use of digital technology to transmit or receive across the radio spectrum. Digital transmission by radio waves includes digital broadcasting, and especially digital audio radio services. Types In digital broadcasting sy ...

technology and

Digital Compact Cassette The Digital Compact Cassette (DCC) is a magnetic tape sound recording format introduced by Philips and Matsushita Electric in late and marketed as the successor to the standard analog Compact Cassette. It was also a direct competitor to Sony ...

Storage

The CD-Text information is stored in the subchannels ''R'' to ''W'' on the disc. This information is usually stored in the subchannels in the lead-in area of the disc, where there is roughly 5 kilobytes of space available. It can also be stored on the main program area of the disc (where the audio tracks are), which can store about 31 megabytes.Unofficial CD Text FAQ
Since the R to W channels are not used in the Red Book specification of audio CDs, they are not read by all CD players, which prevents some devices from reading CD-Text information.

Format

CD-text data is defined in a scattered manner between MMC-3 and Sony documentation. The below uses GNU libcdio's description.
in GNU libcdio documentation. Provides references to MMC-3 and Sony standards. On the lowest level, CD-text is stored in 18-byte "pack" units; this part is defined in MMC-3 Annex J. Each pack consists of 4 bytes of header (type indicator, track number reference, sequential counter, block number and character position indicator NCPI, 12 bytes of payload, and 2 bytes of CRC. The type indicator ranges from 0x80 to 0x8F, the 13 defined values being:MMC-3 Draft R10G
/ref> The BNPCI is used to define information that does not fit in one pack. This can be text or binary data. The BNCPI also indicates whether the text is single-byte or double-byte data in the top bit. This determines how

null-terminated string In computer programming, a null-terminated string is a character string stored as an array containing the characters and terminated with a null character (a character with a value of zero, called NUL in this article). Alternative names are C str ...

s are defined one or two bytes of 0x00. (Note: the DBCS mode is rarely, if ever, used. Its special null handling is not necessary for computer DBCS code pages, as they are "hybrid" with ASCII and compatible in the NUL behavior.

UTF-16 UTF-16 (16-bit Unicode Transformation Format) is a character encoding capable of encoding all 1,112,064 valid code points of Unicode (in fact this number of code points is dictated by the design of UTF-16). The encoding is variable-length, as cod ...

could be the intended use.) For block types listed above as "character" (per MMC-3), the payload is a simple null-terminated string. (MMC-3 is written confusingly here it describes the encoding as "ASCII" in the pack type table despite mentioning the BNCPI flag modifying its behavior later.) The descriptions of the binary fields are vague, but the developers of GNU libcdio has either matched them to sections of MMC-3 or written new descriptions based on Sony's sample. Another layer of encoding specification is found at this payload level, in the SIZE_INFO block. Here the first byte may be used to indicate the encoding,

ASCII ASCII ( ), abbreviated from American Standard Code for Information Interchange, is a character encoding standard for electronic communication. ASCII codes represent text in computers, telecommunications equipment, and other devices. Because ...

Latin-1 ISO/IEC 8859-1:1998, ''Information technology — 8-bit single-byte coded graphic character sets — Part 1: Latin alphabet No. 1'', is part of the ISO/IEC 8859 series of ASCII-based standard character encodings, first edition published in 1 ...

, or "MS-JIS". This is supported by the original Sony authoring tools.

References

External links

CD-Recordable FAQ, question 3-28: How do I add CD-Text information?
{{DEFAULTSORT:Cd-Text Compact disc Metadata

Storage

Format

See also

References

External links