Sony Dynamic Digital Sound

Sony Dynamic Digital Sound (Japanese: ソニーダイナミックデジタルサウンド, Hepburn: Sonī Dainamikku Dejitaru Saundo^?, SDDS) is a cinema sound system developed by Sony. Compressed digital sound information is recorded on both outer edges of the 35 mm film release print. The system supports up to eight independent channels of sound: five front channels, two surround channels and a single sub-bass channel. The eight channel arrangement is similar to large format film magnetic sound formats like Cinerama and Cinemiracle. The five front channels are useful for very large cinema auditoriums where the angular distance between center and left/right channels may be considerable. SDDS decoders provide the ability to downmix to fewer channels if required.

Although originally slated to premier with Hook, the SDDS project was delayed and instead premiered on June 17, 1993, with the Arnold Schwarzenegger film Last Action Hero. Since then, over 1,400 movies have been mixed in Sony Dynamic Digital Sound, and as early as 1999 over 6,750 movie theaters were equipped with SDDS.

The code name for the SDDS project was "Green Lantern", taken from the name of the comic book hero and the old term of "magic lantern" used to describe the original projected pictures in the late 19th century. Green came to mind because the key to imprinting the 8 micrometre data bits was to use a green laser.

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