An audio format is a medium for sound recording and reproduction. 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. Note on the use of analog compared to digital in this list; the definition of digital used here for early formats is that which is represented using discrete values rather than fluctuating variables. A piano roll is digital as it has discrete values, that being a hole for each key, unlike a phonograph record which is analog with a fluctuating groove.

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

Timeline of audio format developments Year Physical media formats Recording formats 1805 Panharmonicon Digital, automated sound reproducing machine. 1810s Organ Cob Mechanical digital, also known as a barrel organ. Nails in wooden cylinder actuate mechanical parts of organ. 1817 Apollonicon Digital, automated sound reproducing machine. 1851 Piano Cylinder Digital, automatically played by means of revolving cylinders 1877 Tinfoil Phonograph Analog; sound waveform transcribed to tinfoil 1883 Piano roll Digital (vacuum-operated piano) 1886 Music Box disc Digital (vacuum-operated music box)Late 1880s Brown Wax cylinder Analog; vertical groove, vertical stylus motion – could be re-recorded Ediphone, Dictaphone Analog, the Ediphone and subsequent wax cylinders used in Edison's other product lines continued to be sold up until 1929 when the Edison Manufacturing Company folded. 1894 Pathé cylinder Mechanical analog; vertical grooves, vertical stylus motion 1897 78rpm Record (Emile Berliner Patent) Mechanical analog; lateral groove, horizontal stylus motion – early examples made from hard rubber, most made from shellac. 1898 Wire recording Analog; magnetization; DC bias 1902 Edison Gold Moulded Record Mechanical analog; vertical groove, horizontal stylus motion – made from hard black wax – 160 rpm standard – 100 threads per inch 1903 Phonograph Postcard Mechanical analog; lateral groove, horizontal stylus motion1905Centre-start phonograph Record Mechanical analog; lateral groove, horizontal stylus motion, starts from the centre of the discPathé disc Mechanical analog; vertical groove, vertical stylus motion. Alternative to 78s manufactured by Pathé Records, Brunswick Records and Grey Gull Records. 1908 2-minute or Amberol Cylinder Record Mechanical analog; vertical groove, vertical stylus motion – made from hard black wax – 160 rpm standard – 200 threads per inch. Best known are the later 12-inch Amberols, which came out in 1912. 1912Diamond Disc Mechanical analog; vertical groove, vertical stylus motion – made from Bakelite or china clay 1924 Electrical cut 78 Mechanical analog; electrically cut from amplified microphone signal, lateral groove, horizontal stylus motion, most at now standardized 78 rpm A record player for electrical cut 78s can play acoustic 78s, but one should not play electrical cut 78s on a record player meant for acoustic 78s. 1930 Filmophone flexible record Mechanical analog; lateral groove, horizontal stylus movement – made from cellulose of various colours – 78 rpm Durium Record or Hit of the Week Records Mechanical analog; lateral groove – made from paper coated in a brown resin (Durium) 1930s Reel-to-reel, magnetic tape Analog; magnetization; AC "bias" dramatically increases linearity/fidelity, tape speed at 30 ips, later 15 ips and other refined speeds: ips, ips, ips Electrical transcriptions Mechanical analog; electrically cut from amplified microphone signal, high fidelity sound, lateral or vertical groove, horizontal or vertical stylus motion, most discs 16" at  rpm 1942 SoundScriber Mechanical analog; vertical groove, 4–6 inch discs, it recorded sound by pressing grooves into soft vinyl discs 1947 Dictabelt (Memobelt) Analog, medium consisting of a thin, plastic belt 3.5" wide that was placed on a cylinder and rotated like a tank tread, developed by the Dictaphone company in 1947 1948 33.3 RPM LP record (Columbia) Analog, with preemphasis and other equalization techniques (LP, RIAA); lateral groove, horizontal stylus motion; discs 7", 10" and 12" at  rpm, 1st LP Columbia ML 4001 Milstein, Mendelssohn Violin Concerto 1949 Vinyl 45 record (RCA) Analog 45 rpm vinyl 7" disk, first 45 pressed "PeeWee the Piccolo" RCA 47-0147 Indianapolis 1950 Tefifon Electro–mechanical analog, vinyl belt housed in a cassette, used an embossing technique using a stylus to imprint the information, was the first thing to resemble a modern audio cassette 16 2/3rpm vinyl record Mechanical analog; lateral groove, horizontal stylus motion – played at half the regular speed of an LP 1951 Minifon P55 Analog, magnetic wire on reel, 30 cm/s or about 11.8 ips was quickly adopted by many governments as being the ultimate "spy" recorder of its day 1957 Stereophonic vinyl record Analog, with pre-emphasis and other equalization techniques. Combination lateral/vertical stylus motion with each channel encoded 45 degrees to the vertical Dictet Analog, tape, 2.48 in/s, (3-inch reels housed 5.875 × 3 × .4375 inch cassette), developed by the Dictaphone Corp 1958 RCA tape cartridge (Sound Tape) (Magazine Loading Cartridge) Analog, inch wide tape (stereo & mono), in/s & 1.875 in/s, one of the first attempts to offer reel-to-reel tape recording quality in a convenient format for the consumer market 1959 NAB Cart Tape (Fidelipac) Analog, inch wide tape in cartridge, in/s & 15 in/s, Introduced in 1959 by Collins Radio, the cart tape format was designed for use by radio broadcasters to play commercials, bumpers and announcements Synchrofax Sound Paper Magnetic coating on paper. 1961 Orrtronic Tapette. Analog, endless tape cartridge. 1962 4-Track (Muntz Stereo-Pak) Analog, tape, in/s, endless-loop cartridge 1963 Compact cassette Analog, with bias. tape, ips. 1970: introduced Dolby noise reduction 1964 Sanyo Micro Pack 35Channel Master 6546Westinghouse H29R1 inch wide tape housed in a transparent cartridge measuring 2.6 × 2.9 × 1.9 inches, tape was stored on two reels residing atop one another, keeping the cartridge compact Sabamobil A cartridge format for embedding and easy handling usual 3-inch-tape-reels with inch tape, compatible to reel-to-reel audio recording in ips. 1965 8-Track (Stereo-8) Analog, inch wide tape, in/s, endless-loop cartridge DC-International cassette system Analog cassette format introduced by Grundig, Telefunken and Blaupunkt: 120 × 77 × 12 mm cassette with inch wide tape run at 5.08 cm per second. 1966 PlayTape Analog, inch wide tape, endless-loop cartridge, introduced by Frank Stanton 1969 Microcassette Analog, inch wide tape, used generally for note taking, mostly mono, some stereo (developed in the early '80s). 2.4 cm/s or 1.2 cm/s Minicassette Analog, inch wide tape, used generally for note taking, 1.2 cm/s 1970 Quadraphonic 8-Track (Quad-8) (Q8) Analog, inch wide tape, in/s, 4-channel stereo, endless-loop cartridge 1971 Quadraphonic Vinyl Record (CD-4) (SQ Matrix) Analog, introduced by CBS Records for matrix and RCA / JVC for CD-4

Recorded two tracks on both stereo channels, requiring a decoder to hear all four tracks. Despite this, the format is playable on any LP turntable. 1971 HiPac Analog, a successor of the 1966 PlayTape, using tape width of the 1963 Compact Cassette, Japan only1976 Dolby Stereo cinema surround sound Analog Elcaset Analog, name comes from "L-Cassette/Large Cassette" 1982 Compact Disc (CD-DA) Digital. Linear PCM (LPCM) 1986 High Definition Compatible Digital (HDCD) Digital. Redbook compatible physical CD containing 20–24 bit information (uses linear pulse-code modulation (LPCM)) 1987 Digital Audio Tape (DAT) Digital. This audio format famously caused controversy among recording companies when released due to the potential of perfect digital copies to increase piracy 1988 AIFF (file format) Digital. Audio Interchange File Format (AIFF) 1992 Digital Compact Cassette (DCC) Digital, inch wide tape,  in/s, introduced by Philips and Matsushita in late 1992, marketed as the successor to the standard analog compact cassette WAV (file format) Digital. Named after the waveform created by a sound wave. Dolby Digital Cinema Sound Digital. Also known as Dolby Stereo Digital until 1994. MiniDisc (MD) Digital. Adaptive Transform Acoustic Coding (ATRAC) 1993 DTS, SDDS, MP3 (file formats) Digital. Digital Theatre System (DTS), Sony Dynamic Digital Sound (SDDS), MPEG-1 Audio Layer III (MP3) 1994 TwinVQ Digital. 1995 RealAudio 1997 DTS-CD Digital. DTS audio 1998 WavPack (file format) Digital. PCM, lossless compression (2002 hybrid compression) (2016 DSD support) 1999 DVD-Audio Digital. Including Meridian Lossless Packing (MLP), Linear PCM (LPCM), Dolby Digital (AC-3) and Digital Theatre System (DTS) Super Audio CD (SACD) Digital. Direct Stream Digital WMA (file format) Digital. Windows Media Audio TTA (file format) Digital. The True Audio Lossless Codec. 2000 FLAC (file format) Digital. Free Lossless Audio Codec (open, non-proprietary, patent-and-royalty-free) Ogg Vorbis (file format) Digital. Vorbis compressed audio format (open, non-proprietary, patent-and-royalty-free) DSDIFF (file format) Digital. DSD, optional DST compression APE (file format) Digital. Monkey's Audio 2001 AAC (file format) Digital. Advanced Audio Coding 2002 WSD (file format) Digital. DSD 2004 ALE or ALAC (file formats) Digital. Apple Lossless 2005 DSF (file format) Digital. DSD 2008 slotMusic Digital. Usually at 320 kbit/s MP3 on microSD or microSDHC. Blu-spec CD Digital. PCM 2012 Opus (file format) Digital. Opus lossy audio coding format (IETF standard, open, non-proprietary, royalty-free) 2016 Blu-Ray HFPA Digital. Audio-only version of Blu-Ray.

See also Timeline of video formats Format war Audio data compression

References

External links Museum Of Obsolete Media – Audio Formats