Dolby Digital Sony Dynamic Digital Sound Obsolete formats Cinema Digital Sound, an optical format which was the first commercial digital sound format, used between 1990 and 1992 Fantasound. This was a system developed by RCA and Disney Studios with a multi-channel soundtrack recorded on a separate strip of film from the picture. It was used for the initial release of Walt Disney's Fantasia (1940) Phonofilm, patented by Lee De Forest in 1919, defunct by 1929 See also Charles A. Hoxie List of film formats List of film sound systems Movietone sound system Optigan Phonofilm RCA Photophone Variophone Eugène Lauste Joseph Tykociński-Tykociner References External links Multichannel Film Sound (MKPE) Audiovisual introductions in 1919 Film and video technology Film sound production History of film Motion picture film formats Sound