- Audio format
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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: 7½ ips, 3¾ ips, 1⅞ ips 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 33⅓ rpm 1948 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 33⅓ 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 (6.4 mm) tape, 3¾ in/s, endless loop cartridge. 1963 Compact Cassette Analog, with bias, preemphasis, 0.15-inch-wide (3.8 mm) tape, 1⅞ in/s. 1970: introduced Dolby noise reduction. 1965 8-Track (Stereo-8) Analog, ¼ inch wide tape, 3¾ in/s, endless loop cartridge. 1969 Microcassette Analog, ⅛ inch wide tape, used generally for notetaking, mostly mono, some stereo. 2.4 cm/s or 1.2 cm/s. Minicassette Analog, ⅛ inch wide tape, used generally for notetaking, 1.2 cm/s 1970 Quadraphonic 8-Track (Quad-8) (Q8) Analog, ¼ inch wide tape, 3¾ in/s, 4 Channel Stereo, endless loop cartridge. 1971 Quadraphonic Vinyl Record (CD-4) (SQ Matrix) Analog. 1975 Betamax Digital Audio Dolby Stereo cinema surround sound 1976 Elcaset Analog. 1978 Laserdisc Digital. 1982 Compact Disc (CD-DA) Digital. PCM 1985 Audio Interchange File Format (AIFF) 1985 Sound Designer (by Digidesign) 1986 High Definition Compatible Digital (HDCD) Digital. Redbook compatible physical CD containing 20–24 bit information. 1987 Digital Audio Tape (DAT) Digital. 1991 MiniDisc (MD) Digital. Adaptive Transform Acoustic Coding (ATRAC) 1992 Digital Compact Cassette (DCC) Digital. WAVEform (WAV) Dolby Digital surround cinema sound
1993 Digital Theatre System (DTS) 1997 DVD Dolby Digital DTS-CD DTS Audio 1999 DVD-Audio Digital. Super Audio CD (SACD) Direct Stream Digital Windows Media Audio (WMA) The True Audio Lossless Codec (TTA) 2000 Free Lossless Audio Codec (FLAC) 2001 Advanced audio coding (AAC) 2002 Ogg Vorbis 2003 DualDisc Digital. 2004 Apple Lossless (ALE or ALAC) 2005 HD DVD Dolby TrueHD, DTS-HD Master Audio OggPCM 2006 Blu-ray Disc Dolby TrueHD, DTS-HD Master Audio 2008 slotMusic 320kb/s MP3 on microSD or microSDHC NEW CD Blu-spec CD
See also
- Audio data compression
- Audio file format
- Format war
External links
Music technology Sound recording Recording media Gramophone record · Magnetic tape · Compact Cassette · Compact Disc · DAT · Hard disk · MiniDisc · MP3Analog recording Reel-to-reel audio recording · 8-track cartridge · Amplifier · Analog vs. digital · Cassette player · Experimental musical instrument · Loudspeaker · Phonograph · Pianola · Tape recorderDigital audio Live music Electronic music Software People and organisations Related topics Categories:- Audio storage
- Audio format converters
- Technology timelines
- Technology-related lists
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