CD-Text
CD-Text is part of the CD+G extension to the Red Book standard for audio CDs. It allows for storage of additional information (e.g. album name, song name, and artist) on a standards-compliant audio CD. The information is stored in the lead-in area of the CD, where there is roughly five kilobytes of space available, or in the R through W subcode channels on the disc, which are not used by strict Red Book CDs. About 24 megabytes of information can be stored there. The text is stored in a format usable by the Interactive Text Transmission System (ITTS). ITTS is also used by Digital Audio Broadcasting or the MiniDisc.
Note that the CD+G or “karaoke” extension also uses the R-W subcode channels to store low resolution graphics.
Read more about this topic: Compact Disc Subcode