The R to W data are protected by a Reed Solomon error correction code. Eight times interleaving is added to improve burst error correction. The R to W data can be in any of the following modes defined within the subcode channels. It is now possible to buy CD-G Karaoke versions of portable CD hifi audio equipment. They only need a television set to see the graphics and text which are the song lyrics and the owner has a portable self-contained Karaoke system.
User mode is intended for professional applications.
The meaning of the data is application specific. CD TEXT CD TEXT is a recent addition to the CD audio specification allowing disc and track related information to be added to standard audio CDs for playback on suitably equipped CD audio players. The CD TEXT data is repeated throughout each track to reduce the delay in retrieving the data. The specification also allows for future additional data such as JPEG coded images. Menus are used for the selection of text for display.