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, in which 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 such as 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.