CD-Text
CD-Text is an extension of an audio CD (more precisely an extension of the Red Book of audio CDs), which contains textual information such as title, artist and name of the individual pieces of music. Some CD players can display this text while playing. Playability on devices that do not support CD-Text is usually not affected. With some, mostly older CD players, access to tracks can be extended by CD-Text.
technology
The text is always stored in the RW subcodes of the CD in the form of the Interactive Text Transmission System (ITTS) (which is also used with DAB and MiniDisc ) and can be in two possible positions: in the lead-in on the CD or in parallel to the music.
In the first case, about 5 KB are available for the data. This is the normal storage location for title information. This area can also by most CD-ROM - drives are read because the MMC specification defines the relevant commands. The extension of the MMC standard required for this is based on a proposal by Sony .
CD-Text data that is recorded parallel to the music is currently not provided. There are, however, CDs that contain data in the RW subcodes within the tracks that can be read by a few drives and are therefore not commonly used. The 31 MB available here are used for applications such as CD + G (CDs with additional pictures, e.g. for karaoke ).
The maximum number of characters that CD-Text can have is limited. A maximum of 64 characters can be used for the track title and 64 characters for the artist as well. There is no obvious limit to album titles and album artists. The total number of characters on the disc must not exceed 3024 characters. Otherwise no CD-Text will be shown in the display. The same applies if the track artist or track title has more than 64 characters; then many CD players refuse to display CD-Text. The format of the character encoding is specified (if the data is stored in the lead-in) in the Pack Type Indicator ID1 for album title, singer, songwriter, composer, arranger and provider. Defined values are 0 ( ISO 8859-1 ), 1 ( ISO 646 = 7 bit ASCII), 0x80 ( Japanese ), 0x81 ( Korean ) and 0x82 ( Chinese ), although the specification lacks precise information about the type of coding hide behind the Korean and Chinese variants ( "to be defined" ). The standard used is 0 (ISO 8859-1), which is required by practically all burning programs and CD players.
Special characters and umlauts can be used. Depending on the type of display on the playback device ( dot matrix or segment display ), it may happen that the special characters are displayed as spaces. Lowercase letters are always shown in upper case on segment displays.
application
Writing: Most burning programs support writing CD-Text in the lead-in. However, this often has to be activated separately. The CD must be burned in SAO or DAO mode (recommended) or in raw mode . If the RAW mode is used, CD-Text can also be generated on devices that are not intended for CD-Text.
Reading: To display the CD text, special playback devices with the appropriate support are required, which, for example, almost all modern car radios have. By updating the firmware (if possible), this function could also be retrofitted for conventional CD players, but this is usually hampered by the lack of display options for letters. Almost all CD burning programs allow CD-Text to be added when copying, based on information from CDDB or freedb .
Commercial CDs
An increasing number of retail CDs contain CD-Text. These include above all those from Sony Music , which have been provided with CD-Text since April 1997.
Individual evidence
- ↑ Feurio Questions & Answers - Questions about CD-TEXT: Maximum size of CD-Text information? Retrieved December 28, 2008 .
- ↑ Feurio Questions & Answers - Questions about CD-TEXT: Character set for CD-Text (special characters)? Retrieved December 28, 2008 .