Dolby Laboratories

Dolby Laboratories, Inc. is an American company specializing in audio noise reduction and audio encoding/compression. Dolby licenses its technologies to consumer electronics manufacturers.


Dolby Labs was founded by Ray Dolby in London, United Kingdom, in 1965. In the same year, he invented the Dolby Noise Reduction System, a form of audio signal processing for reducing the background hissing sound on audio tape recordings. His first U.S. patent on the technology was filed in 1969, four years later. The method was first used by Decca Records in the UK.
He moved the company headquarters to the United States in 1976. The first product Dolby Labs produced was the Dolby 301 unit which incorporated Type A Dolby Noise Reduction, a compander-based noise reduction system. These units were intended for use in professional recording studios.
Dolby was persuaded by Henry Kloss of KLH to manufacture a consumer version of his noise reduction. Dolby worked more on companding systems and introduced Type B in 1968.
Dolby also sought to improve film sound. As the corporation's history explains:
The first film with Dolby sound was A Clockwork Orange, which used Dolby noise reduction on all pre-mixes and masters, but a conventional optical sound track on release prints. Callan was the first film with a Dolby-encoded optical soundtrack. In 1975, Dolby released Dolby Stereo, which included a noise reduction system in addition to more audio channels. The first film with a Dolby-encoded stereo optical soundtrack was Lisztomania, although this only used an LCR encoding technique. The first true LCRS soundtrack was encoded on the movie A Star Is Born in 1976. In less than ten years, 6,000 cinemas worldwide were equipped to use Dolby Stereo sound. Dolby reworked the system slightly for home use and introduced Dolby Surround, which only extracted a surround channel, and the more impressive Dolby Pro Logic, which was the domestic equivalent of the theatrical Dolby Stereo.
Dolby developed a digital surround sound compression scheme for the cinema. Dolby Stereo Digital was first featured on the 1992 film Batman Returns. Introduced to the home theater market as Dolby AC-3 with the 1995 laserdisc release of Clear and Present Danger, the format did not become widespread in the consumer market, partly because of extra hardware that was necessary to make use of it, until it was adopted as part of the DVD specification. Dolby Digital is now found in the HDTV standard of the United States, DVD players, and many satellite-TV and cable-TV receivers.
Dolby developed a digital surround sound compression scheme for the TV series The Simpsons.
On February 17, 2005, the company became public, offering its shares on the New York Stock Exchange, under the symbol DLB. On March 15, 2005, Dolby celebrated its fortieth anniversary at the ShoWest 2005 Festival in San Francisco.
On January 8, 2007, Dolby announced the arrival of Dolby Volume at the International Consumer Electronics Show.
On June 18, 2010, Dolby introduced Dolby Surround 7.1, and set up theaters worldwide with 7.1 surround speaker setups to deliver theatrical 7.1 surround sound. The first film to be released with this format was Pixar's Toy Story 3 which was later followed by 50 releases using the format. About eighty percent of films released are mixed in Dolby Surround 7.1 by default.
In April 2012, Dolby introduced its Dolby Atmos, a new cinematic technology adding overhead sound, first applied in Pixar's motion picture Brave. In July 2014, Dolby Laboratories announced plans to bring Atmos to home theater. The first television show to use the technology on disc was Game of Thrones.
On February 24, 2014, Dolby acquired Doremi Labs for $92.5 million in cash plus an additional $20 million in contingent consideration that may be earned over a four-year period.
In May 2019, Dolby decided to add Dolby Atmos to hundreds of newer songs in the music industry.


Analog audio noise reduction

Over the years Dolby has introduced several surround sound systems. Their differences are explained below.
Dolby StereoDolby MP Matrix1975Cinema use with optical technology. Uses Dolby A for noise reduction. 4:2 encoded for 35mm film and 2:4 decoded back to 4.0 by Dolby Stereo Processor. Magnetic 6-Track variant for 70mm.FL FR with C and MonoSurround matrixed
Dolby SurroundDolby Surround1982First Home use. Analog. Upmix stereo to Surround 3.0.FL FR and MonoSurround matrixed
Dolby Stereo SR1986Cinema use. Uses Dolby SR for noise reduction.FL FR with C and MonoSurround matrixed
Dolby Pro Logic1987Improved Dolby Surround. Upmix Stereo to Surround 4.0.FL FR with C and MonoSurround matrixed
Dolby DigitalAC-31986 Modern
1992 Film
1995 Laser Disc
Discrete channel encoder/decoder. Pro Logic Decoder can be used for downmixed stereo inputs.FL FR C SL SR SUB
Dolby Digital EX/Dolby Digital Surround EX1999non-discrete 6.1 or 7.1 FL FR C SL SR SUB
Dolby Pro Logic II2000Improved Dolby Pro Logic. Upmix Stereo to Surround 5.1 in either Movie, Music, or Game mode.FL FR C SL SR SUB
Dolby Pro Logic IIx2002Upmix Stereo or Surround 5.1 to 6.1 or 7.1 in either Movie, Music, or Game mode.FL FR C SL SR SUB Left Back and Right Back
Dolby Digital PlusDolby Media Encoder2005Lossy compression codec; 48 kHz sampling frequency, 20-bit word length; supports data rates of 32 kbit/s – 6 Mbit/s, scalable, including 768 kbit/s – 1.5 Mbit/s on high-definition optical discs, typically, and 256 kbit/s for broadcast and online. 1.0- to 7.1-channel support for current media applications; extensible to 16 channels; discrete. Backward compatible with Dolby Digital through S/PDIF connection up to 640 kbit/s. Supports Dolby Metadata.FL FR C SL SR SUB Left Back and Right Back
Dolby TrueHDDolby Media Encoder2005Lossless compression codec; supports 44.1 kHz to 192 kHz sampling frequency up to 24-bit word length; supports variable data rate up to 18 Mbit/s; maximum channel support is 16 channels as presently deployed. Higher bitrate than Dolby Digital Plus. Blu-ray Disc channel support up to eight channels of 96 kHz/24-bit audio; six channels up to 192 kHz/24-bit; and two- to six-channel support up to 192 kHz/24-bit maximum bit rate up to the maximum of 18 Mbit/s.
Dolby Pro Logic IIzDolby Laboratories2009Upmix Stereo or Surround 5.1/7.1 to 7.1 Height or 9.1 with the addition of front height channels. L, C, R, Ls, Rs, Lrs, Rrs, LFE, Lvh and Rvh