CD single in the context of A-side and B-side

The compact disc (CD) is a digital optical disc data storage format co-developed by Philips and Sony to store and play digital audio recordings. It employs the Compact Disc Digital Audio (CD-DA) standard and is capable of holding uncompressed stereo audio. First released in Japan in October 1982, the CD was the second optical disc format to reach the market, following the larger LaserDisc (LD). In later years, the technology was adapted for computer data storage as CD-ROM and subsequently expanded into various writable and multimedia formats. As of 2007, over 200 billion CDs (including audio CDs, CD-ROMs, and CD-Rs) had been sold worldwide.

Standard CDs have a diameter of 120 millimetres (4.7 inches) and typically hold up to 74 minutes of audio or approximately 650 MiB (681,574,400 bytes) of data. This was later regularly extended to 80 minutes or 700 MiB (734,003,200 bytes) by reducing the spacing between data tracks, with some discs unofficially reaching up to 99 minutes or 870 MiB (912,261,120 bytes) which falls outside established specifications. Smaller variants, such as the Mini CD, range from 60 to 80 millimetres (2.4 to 3.1 in) in diameter and have been used for CD singles or distributing device drivers and software.

Compact disc (CD) is a digital optical disc data storage format co-developed by Philips and Sony to store and play digital audio recordings. It employs the Compact Disc Digital Audio (CD-DA) standard and is capable of holding uncompressed stereo audio. First released in Japan in October 1982, the CD was the second optical disc format to reach the market, following the larger LaserDisc (LD). In later years, the technology was adapted for computer data storage as CD-ROM and subsequently expanded into various writable and multimedia formats. As of 2007, over 200 billion CDs (including audio CDs, CD-ROMs, and CD-Rs) had been sold worldwide.

Standard CDs have a diameter of 120 millimetres (4.7 inches) and typically hold up to 74 minutes of audio or approximately 650 MiB (681,574,400 bytes) of data. This was later regularly extended to 80 minutes or 700 MiB (734,003,200 bytes) by reducing the spacing between data tracks, with some discs unofficially reaching up to 99 minutes or 870 MiB (912,261,120 bytes) which falls outside established specifications. Smaller variants, such as the Mini CD, range from 60 to 80 millimetres (2.4 to 3.1 in) in diameter and have been used for CD singles or distributing device drivers and software.

MiniDVD or 8 cm DVD (also "3 inch DVD") is a DVD disc with a reduced diameter of 8 centimetres (3.15 in). It has been most commonly used in camcorders due to its compact size. The most common MiniDVDs are single layered and hold 1.4 GB of data, but there are variants that can offer up to 5.2 GB of storage space, through a combination of dual layers and dual sides.

8 cm DVDs were originally used for music videos and as such became known as DVD single, similarly to how 8 cm optical discs were previously used for music singles on compact discs (i.e. CD single and miniCD). However the MiniDVD format has been mostly used as recordable discs in DVD-based camcorders during the 2000s; a single layer disc can record up to 30 minutes of standard definition video. A number of movies and TV shows have also been released on the format in the mid-2000s, usually targeting children using low-cost small players.