Dolby


Dolby Laboratories, Inc. is an American technology corporation specializing in audio noise reduction, audio encoding/compression, spatial audio, and high-dynamic-range television imaging. Dolby licenses its technologies to consumer electronics manufacturers.

History

Dolby Labs was founded by Ray Dolby in London, England, 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 cassette 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. After this, other companies began purchasing Dolby’s A301 technology, which was the professional noise reduction system used in recording, motion picture, broadcasting stations and communications networks. These companies include BBC, Pye, IBC, CBS Studios, RCA, and Granada.
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 continued to work 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. The company was approached by Stanley Kubrick, who wanted to use Dolby’s noise reduction system to facilitate the film’s extensive mixing. The film went on to use Dolby noise reduction on all pre-mixes and masters, but a conventional optical soundtrack 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. In 2005, Dolby's stereo 4-channel optical theater surround was inducted into the TECnology Hall of Fame, an honor given to "products and innovations that have had an enduring impact on the development of audio technology."
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 extra hardware was needed 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 40th 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, which added two rear surround channels to the 5.1 format. The first film to be released in this format was Pixar's Toy Story 3.
In April 2012, Dolby introduced Dolby Atmos, a new cinema technology adding overhead sound, first applied in Pixar's motion picture Brave. In the same year, Dolby bought the naming rights of Hollywood's Dolby Theatre, the venue of the annual Academy Awards ceremony. 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 2015, Dolby reopened the Vine Theatre, Hollywood as a 70-seat showcase theater, known as Dolby @ Vine or Dolby Screening Room Hollywood Vine.
In May 2019, Dolby added Dolby Atmos to hundreds of newer songs in the music industry.
In May 2020, Dolby launched a developer platform, Dolby.io, aimed at providing developers self-service access to Dolby technologies through public APIs. It allows any person, organization, small and big, to integrate in their websites, apps, games, etc. features such as media enhancements and transcoding, spatial audio, high-quality video communication and low-latency streaming.
In May 2025, BBC Radio 4 broadcast Surrounded by Sound: Ray Dolby and the Art of Noise Reduction to mark Dolby Laboratories' 60th anniversary. This included interviews with his widow Dagmar and two of the first Dolby sound engineers, David Robinson and Ioan Allen, and Crimson Tide and Armageddon sound designer Midge Costin. A version of the programme was made in binaural sound.

Technologies

Analog audio noise reduction

  • Dolby A: professional noise reduction systems for analog reel-to-reel tape and cassettes.
  • Dolby NR/B/C/S: consumer noise reduction systems for tapes and analog cassettes.
  • Dolby SR : professional four-channel noise reduction system in use since 1986, which improves the dynamic range of analog recordings and transmissions by as much as 25 dB. Dolby SR is utilized by recording and post-production engineers, broadcasters, and other audio professionals. It is also the benchmark in analog film sound, being included today on nearly all 35 mm film prints. On films with digital soundtracks, the SR track is used in cinemas not equipped for digital playback, and it serves as a backup in case of problems with the digital track.
  • Dolby FM: noise reduction system for FM broadcast radio. Dolby FM was tried by a few radio stations starting with WFMT in 1971. It used Dolby B, combined with 25 microsecond pre-emphasis. A small number of models of tuners and receivers were offered with the necessary decoder built in. In addition, a few cassette deck models appeared that allowed the deck's internal Dolby B decoder to be put in the line level pass-through path, permitting its use with Dolby FM broadcasts. The system was not successful and was on the decline by 1974.
  • Dolby HX Pro: single-ended system used on high-end tape recorders to increase headroom. The recording bias is lowered as the high-frequency component of the signal being recorded increases, and vice versa. It does nothing to the actual audio that is being recorded, and it does not require a special decoder. Any HX Pro recorded tape will have, in theory, better sound on any deck.
  • Dolby Advanced Audio: Dolby surround sound, locking preferred volume level, optimizes audio performance for specific PC models and lets turning up the volume to the built-in speakers without distorting the sound.

    Audio encoding/compression

  • Dolby Surround
  • Dolby Digital is a lossy audio compression format. It supports channel configurations from mono up to six discrete channels. This format first allowed and popularized surround sound. It was first developed for movie theater sound and spread to Laserdisc and DVD. It has been adopted in many broadcast formats including all North American digital television, DVB-T, direct broadcast satellite, cable television, DTMB, IPTV, and surround sound radio services. It is also part of both the Blu-ray and the now-defunct HD DVD standards. Dolby Digital is used to enable surround sound output by most video game consoles. Several personal computers support converting all audio to Dolby Digital for output.
  • * Dolby Digital EX: introduces a matrix-encoded center rear surround channel to Dolby Digital for 6.1 channel output. This center-rear channel is often split to two rear back speakers for 7.1 channel output.
  • * Dolby Digital Plus is a lossy audio codec based on Dolby Digital that is backward compatible, but more advanced. The DVD Forum has selected Dolby Digital Plus as a standard audio format for HD DVD video. It supports data rates up to 6 Mbit/s, an increase from Dolby Digital's 640 kbit/s maximum. On Blu-ray, Dolby Digital Plus is implemented differently, as a legacy 640 kbit/s Dolby Digital stream plus an additional stream to expand the surround sound, with a total bandwidth of approximately 1.7 Mbit/s. Dolby Digital Plus is also optimized for limited data-rate environments such as Digital broadcasting.
  • * Dolby Digital Live is a real-time hardware encoding technology for interactive media such as video games. It converts any audio signals on a PC or game console into the 5.1-channel Dolby Digital format and transports it via a single S/PDIF cable. A similar technology known as DTS Connect is available from competitor DTS.
  • Image:Dolby-E Hardware.jpg|thumb|180px|Dolby E selected hardware Dolby E: professional coding system optimized for the distribution of surround and multichannel audio through digital two-channel post-production and broadcasting infrastructures, or for recording surround audio on two audio tracks of conventional digital video tapes, video servers, communication links, switchers, and routers. The Dolby E signal does not reach viewers at home. It is transcoded to Dolby Digital at a lower data rate for final DTV transmission.
  • Dolby Stereo : original analog optical technology developed for 35 mm prints and is encoded with four sound channels: Left/Center/Right and Surround for ambient sound and special effects. This technology also employs A-type or SR-type noise reduction, listed above with regards to analog cassette tapes. See also Dolby Surround
  • Dolby TrueHD: Offers bit-for-bit sound reproduction identical to the studio master. Over seven full-range 24-bit/96 kHz discrete channels are supported along with the HDMI interface. Theoretically, Dolby TrueHD can support more channels, but this number has been limited to 8 for HD DVD and Blu-ray Disc.
  • Dolby Pulse: released in 2009, it is identical to the HE-AAC v2 codec except for the addition of Dolby metadata, which is common for Dolby's other digital audio codecs. This metadata "ensures consistency of broadcast quality."
  • Dolby AC-4 is a lossy audio compression format that can contain audio channels and/or audio objects.
  • Dolby Atmos is a suite of technologies for immersive audio having both horizontal and vertical sound placement, using a combination of channel and object-based mixing and delivery. It was first introduced in cinemas with Brave. The first game released with Dolby Atmos audio was Star Wars Battlefront. The means of delivering the channels and objects differ given the technical limitations across different media, and the target platform. Dolby Atmos is not a codec; on the consumer market, pre-recorded Dolby Atmos is delivered as an extension to a Dolby TrueHD, Dolby Digital Plus, or Dolby AC-4 stream.