Product Code Database
CD-Text is an extension of the Red Book Compact Disc 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. It was also added to new revisions of the Red Book. Approved Compact Disc Logo configurations. The actual text is stored in a format compatible with Interactive Text Transmission System (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 technology and Digital Compact Cassette.
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 BNCPI), 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
| + CD-Text keywords |
| Character |
| Character |
| Binary |
| Binary |
| Character |
| Character |
| Character |
| Character |
| Character |
| Binary |
| Binary |
| Character |
| Binary |
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 DBCS data in the top bit. This determines how null-terminated strings 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 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, Latin-1, or "MS-JIS". This is supported by the original Sony authoring tools.
See also
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