A CD-ROM is a type of read-only memory consisting of a pre-pressed optical compact disc that contains data computers can read—but not write or erase—CD-ROMs. Some CDs, called enhanced CDs, hold both computer data and audio with the latter capable of being played on a CD player, while data is only usable on a computer.

Compact Disc Digital Audio, also known as Digital Audio Compact Disc or simply as Audio CD, is the standard format for audio compact discs. The standard is defined in the Red Book, one of a series of Rainbow Books that contain the technical specifications for all CD formats. CDDA utilises pulse-code modulation (PCM) and uses a 44,100 Hz sampling frequency and 16-bit resolution, and stores up to 80 minutes of stereo audio per disc.