Dolby Labs was founded byRay Dolby(1933–2013) inLondon,England, in 1965.[5]In the same year, he invented theDolby Noise Reduction system,a form ofaudio signal processingfor reducing the background hissing sound oncassette taperecordings.[6]His first U.S. patent on the technology was filed in 1969, four years later. The method was first used byDecca Recordsin the UK.[7]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.[8]These companies includeBBC,Pye,IBC, CBS Studios, RCA, and Granada.[9]
He moved the company headquarters to the United States (San Francisco,California) in 1976.[10]The first product Dolby Labs produced was the Dolby 301 unit which incorporated Type A Dolby Noise Reduction, acompander-based noise reduction system.[9]These units were intended for use in professional recording studios.
Dolby was persuaded byHenry KlossofKLHto 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:[citation needed]
Upon investigation, Dolby found that many of the limitations inoptical soundstemmed directly from its significantly high background noise. To filter this noise, the high-frequency response of theatre playback systems was deliberately curtailed… To make matters worse, to increase dialogue intelligibility over such systems, sound mixers were recording soundtracks with so much high-frequency pre-emphasis that high distortion resulted.
The first film with Dolby sound wasA Clockwork Orange(1971). The company was approached by Stanley Kubrick, who wanted to use Dolby’s noise reduction system to facilitate the film’s extensive mixing.[11]The film went on to use Dolby noise reduction on all pre-mixes and masters, but a conventional optical soundtrack on release prints.Callan(1974) was the first film with a Dolby-encoded optical soundtrack.[12]In 1975, Dolby releasedDolby Stereo,which included a noise reduction system in addition to more audio channels (Dolby Stereo could actually contain additional center and surround channels matrixed from the left and right). The first film with a Dolby-encoded stereo optical soundtrack wasLisztomania(1975), although this only used an LCR (Left-Center-Right) encoding technique. The first true LCRS (Left-Center-Right-Surround) soundtrack was encoded on the movieA Star Is Bornin 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 introducedDolby Surround,which only extracted a surround channel, and the more impressiveDolby Pro Logic,which was the domestic equivalent of the theatrical Dolby Stereo.[13]
On June 18, 2010, Dolby introducedDolby Surround 7.1,and set up theaters worldwide with 7.1 surround speaker setups to deliver theatrical7.1 surround sound.The first film to be released with this format wasPixar'sToy Story 3which was later followed by fifty releases using the format. About 80% of films released are now mixed in Dolby Surround 7.1 by default.
In April 2012, Dolby introduced itsDolby Atmos,a new cinematic technology adding overhead sound, first applied in Pixar's motion pictureBrave.[15]In July 2014, Dolby Laboratories announced plans to bring Atmos to home theater. The first television show to use the technology on disc wasGame of Thrones.
On February 24, 2014, Dolby acquiredDoremi Labsfor $92.5 million in cash plus an additional $20 million in contingent consideration that may be earned over a four-year period.[16]
In May 2015, Dolby reopenedVine Theatreas a 70-seat showcase theater, known as Dolby @ Vine or Dolby Screening Room Hollywood Vine.[17][18][19]
In May 2019, Dolby added Dolby Atmos to hundreds of newer songs in the music industry.[20]
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.[21]
Dolby NR/B/C/S:consumer noise reduction systems for tapes and analog cassettes.
Dolby SR(Spectral Recording): professional four-channel noise reduction system in use since 1986, which improves the dynamic range of analog recordings and transmissions by as much as 25dB.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 incinemasnot 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 withWFMTin 1971. It used Dolby B, combined with 25 microsecondpre-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 theline levelpass-throughpath, 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 recordingbiasis 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:Dolbysurround 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.[22]
Dolby Digital EX:introduces a matrix-encoded center rear surround channel to Dolby Digital for 6.1 channel output.[23]This center-rear channel is often split to two rear back speakers for 7.1 channel output.
Dolby Digital Plus(also known asE-AC-3) 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 forHD DVDvideo. It supports data rates up to 6 Mbit/s, an increase fromDolby 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 asDigital broadcasting.
Dolby Digital Liveis a real-time hardware encoding technology for interactive media such asvideo games.It converts any audio signals on aPCorgame consoleinto the 5.1-channel Dolby Digital format and transports it via a singleS/PDIFcable.[24]A similar technology known asDTS Connectis available from competitorDTS.
Dolby E selected hardwareDolby 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(also known asStereo A): original analog optical technology developed for 35 mm prints and is encoded with four sound channels: Left/Center/Right (which are located behind the screen) and Surround (which is heard over speakers on the sides and rear of the theatre) 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 alsoDolby 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 (plus anLFEchannel, making it 7.1 surround) along with theHDMIinterface. 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."[25]
Dolby AC-4is a lossy audio compression format that can contain audio channels and/or audio objects.
Dolby Atmosis 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 withBrave (2012 film).The first game released with Dolby Atmos audio wasStar Wars Battlefront (2015 video game).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.
Dolby Virtual Speaker:simulates 5.1 surround sound in a setup of two standard stereo speakers.[26]
Dolby Surround,Dolby Pro Logic,Dolby Pro Logic II,Dolby Pro Logic IIx,andDolby Pro Logic IIz:these decoders expand sound to a greater number of channels. All can decode surround sound that has been matrixed into two channels; some can expand surround sound to a greater number of speakers than the original source material. See the referenced articles for more details on each decoder.
Dolby Mobile:A version of Dolby's surround sound technology specifically designed for mobile phones, notably theHTC Desire HD,LG ArenaandLG Renoir.
Dolby Audio Plug-in for Android:An API packaged as a Java Library that allows Android Developers to take advantage of Dolby Digital Plus Technology embedded into mobile and tablet devices, notably theFire HD,Fire HDX,andSamsung Galaxy Tab 3 series.
Dolby Voice:Hardware and software products for enterprise-level web conferencing.[29]
Dolby Visionis a content mastering and delivery format similar to the HDR10 media profile. It supports bothhigh dynamic range(HDR) andwide color gamut(ITU-R Rec. 2020 and 2100) at all stages from content creation and production to transmission and playback. Dolby Vision includes the Perceptual Quantizier (SMPTE ST-2084) electro-optical transfer function and supports displays with up to 10,000-nit maximum brightness (4,000-nit in practice). It also provides up to 8K resolution and color depth of up to 12-bits (backwards compatible with current 8-bit and 10-bit displays).[38]Dolby Vision can encode mastering display colorimetry information using static metadata (SMPTE ST 2086) and dynamic metadata (SMPTE ST 2094-10, Dolby format) for each scene or frame of a video.[39]Examples of Ultra HD (UHD) Dolby Vision are available in TV, monitor, mobile devices and theater. Dolby Vision content can be delivered onUltra HD Blu-raydiscs,[40][41]over conventional broadcasting, OTT, and onlinestreaming media services.[42]Dolby Vision metadata can be carried via HDMI interface versions 1.4b and above.[43]It also supports IPTPQc2 color space, that is similar to ICtCp. Dolby Vision IQ is an update designed to optimize Dolby Vision content according to the brightness of the room.[44]
ICtCpprovides an improved color representation that is designed for high dynamic range (HDR) and wide color gamut (WCG).[45]An improved constant luminance is an advantage for color processing operations such aschroma subsamplingand gamut mapping where only color information is changed.[45]ICtCp is based on a modification ofIPTcalled ICaCb.[46]
Cinema 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. Discrete Magnetic 6-Track variant for 70mm.
Upmixes non-Encoded Stereo to Surround 5.1. Can also be used to decode Dolby Surround for 5.1 Playback. Consumer Decoders often include specific Movie, Music, or Game modes.
Extension to PLII. Enhancement of either Stereo, Dolby Surround, Dolby Digital 5.1 to 6.1 or 7.1. Decodes Dolby Digital EX to 6.1 or 7.1. Retains Movie, Music, or Game modes in Consumer Products.
Extension to PLIIx. Decodes Stereo, Dolby Surround or Discrete 5.1/6.1/7.1 to 7.1 Height or Full 9.1 with the addition of Front Height Channels. Last Pro Logic Branded Decoder from Dolby.
Dolby reintroduced the Dolby Surround terminology in 2014. The term now refers to a new frequency-domain decoder/upmixer. Dolby Surround is a complete replacement for Pro Logic; it takes in stereo (discrete or matrixed), 5.1 and 7.1 inputs to play over a wide range of output configurations including those with height channels.
Discrete channel encoder/decoder. Stereo output can be generated from the 5 program channels using Pro Logic encoding. This allows systems that are limited to stereo output to carry surround sound.
Lossless 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 (5.1) 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.
Lossy 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.
Cinema: SSLAC. Consumer: Dolby Digital Plus-JOC, MLP, AC-4.
2012
Expands on existing surround sound formats by adding top surround channels and audio objects. Each audio object consists of a mono audio signal plus metadata that describes the sound location, size, and other rendering control parameters. An object renderer is used to convert the audio objects to output channel signals. The use of audio objects allows a sound to be described independently of any specific loudspeaker configuration. For cinema distribution, all audio is losslessly encoded as PCM or SSLAC (Samplerate Scalable Lossless Audio Coding).
Cinema soundtrack channels:
L, R, C, LFE, Lss, Rss (side surrounds), Lrs, Rrs (rear surrounds), Lts, Rts (top surrounds). Note: the number and intended location of _output_ channels is defined at playback based on the available loudspeakers.
^Welch, Rosanne; Lamphier, Peg A. (2019).Technical Innovation in American History: An Encyclopedia of Science and Technology [3 volumes].Santa Barbara, CA: ABC-CLIO. p. 47.ISBN978-1-61069-094-2.
^Billboard (1971).Dolby System's Acceptance Builds Insurmountable Lead.New York: Nielsen Business Media, Inc. p. 23.
US$1.25 billion(2022)
