An audio format is a medium for storing sound and music. The term is applied to both the physical recording media and the recording formats of the audio content – in computer science it is often limited to the audio file format, but its wider use usually refers to the physical method used to store the data.

Music is recorded and distributed using a variety of audio formats, some of which store additional information.

Timeline of audio format developments

Year	Media formats	Recording formats
1877	Phonograph cylinder	Mechanical analog; "hill-and-dale" grooves, vertical stylus motion
1883	Music roll	Mechanical digital (automated musical instruments)
1895	Gramophone record	Mechanical analog; lateral grooves, horizontal stylus motion
1898	Wire recording	Analog; magnetization; no "bias"
1925	Electrical cut record	Mechanical analog; electrically cut from amplified microphone signal, lateral grooves, horizontal stylus motion, discs at 7", 10", 12", most at 78 rpm
1930s	Reel-to-Reel, Magnetic Tape	Analog; magnetization; "bias" dramatically increases linearity/fidelity, tape speed at 30 ips, later 15 ips with NAB equalization; refined speeds: 7 1/2 ips, 3 3/4 ips, 1 7/8 ips
1930s	Electrical transcriptions	Mechanical analog; electrically cut from amplified microphone signal, high fidelity sound, lateral or vertical grooves, horizontal or vertical stylus motion, most discs 16" at 33 1/3 rpm
1948 (Commercial release)	Vinyl Record	Analog, with preemphasis and other equalization techniques (LP, RIAA); lateral grooves, horizontal stylus motion; discs at 7" (most 45 rpm), 10" and 12" (most 33 1/3 rpm)
1957	Stereophonic Vinyl Record	Analog, with preemphasis and other equalization techniques. Combination lateral/vertical stylus motion with each channel encoded 45 degrees to the vertical.
1962	4-Track (Stereo-Pak)	Analog, 1/4 inch wide tape, 3 3/4 inches/sec, endless loop cartridge.
1963	Compact Cassette	Analog, with bias, preemphasis, 0.15 inch wide tape, 17/8 inches/sec. 1970: introduced Dolby noise reduction.
1965	8-Track (Stereo-8)	Analog, 1/4 inch wide tape, 3 3/4 inches/sec, endless loop cartridge.
1969	Microcassette	Analog, 1/8 inch wide tape, used generally for notetaking, mostly mono, some stereo. 2.4 cm/s or 1.2 cm/s.
1969	Minicassette	Analog, 1/8 inch wide tape, used generally for notetaking, 1.2 cm/s
1970	Quadraphonic 8-Track (Quad-8) (Q8)	Analog, 1/4 inch wide tape, 3 3/4 inches/sec, 4 Channel Stereo, endless loop cartridge.
1971	Quadraphonic Vinyl Record (CD-4) (SQ Matrix)
1975	Betamax Digital Audio	'Dolby Stereo' cinema surround sound
1976	Elcaset
1978	Laserdisc
1982	Compact Disc (CD-DA)	PCM
1985		Audio Interchange File Format (AIFF)
1985		Sound Designer (by Digidesign)
1987	Digital Audio Tape (DAT)
1991	MiniDisc (MD)	ATRAC
1992	Digital Compact Cassette (DCC)
1992		WAVEform (WAV) Dolby Digital surround cinema sound
1993		Digital Theatre System (DTS) Sony Dynamic Digital Sound (SDDS)
1995		MP3
1997	DVD	Dolby Digital
1997	DTS-CD	DTS Audio
1999	DVD-Audio
1999	Super Audio CD (SACD)
1999		Windows Media Audio (WMA)
1999		The True Audio Lossless Codec (TTA)
2000		Free Lossless Audio Codec (FLAC)
2001		Advanced audio coding (AAC)
2002		Ogg Vorbis
2003	DualDisc
2004		Apple Lossless (ALE or ALAC)
2005	HD DVD
2005		OggPCM
2006	Blu-Ray
2008		Iklax

See also

• Audio data compression
• Audio file format
• Format war

External links

• recording-history.org