What is SDDS sound format?

Sony Dynamic Digital Sound or SDDS is a theatrical cinema sound system developed by the Japanese multinational company Sony.

In this format, digital sound information is recorded on both outer edges of 35mm film release prints. Altogether, the system supports as many as eight independent channels of sound, including five front channels, two surround channels, and a single sub-bass channel. The front channels are particularly useful in large cinema auditoriums where the angular distance between the center and left/right channels may be considerable.

Originally, the SDDS project was premiered on June 17, 1993, with the Arnold Schwarzenegger film Last Action Hero. Since then, around 1500 movies have been mixed in the format, and, over 6,750 movie theatres were equipped with SDDS by 1999.

However, compared to the other two digital sound formats; Dolby Digital and DTS, SDDS is less popular. As of now, SDDS is not available on any home entertainment format.