COMPATIBLE DIGITAL SOUNDTRACKS FOR 70 MM MOTION PICTURE FILM

摘要

Dolby Digital and Sony SDDS digital signal carrying optical symbols on large-format motion picture film (e.g., film having any of the various 70 mm formats) are recorded in such a way as to permit existing 35 mm optical readers and signal decoders to recover the soundtracks with little or no modification. The normal format of a motion picture soundtrack in the form of a two-dimensional array of photographically recorded symbols (10) representing digital information intended for application to 35 mm motion picture film is modified by stretching the symbols (10) in the direction in which the motion picture film is transported when played, the degree of stretching being commensurate with the increase in film speed of the large-format motion picture film with respect to said 35 mm motion picture film. The stretched format soundtrack is applied to the large-format motion picture film, whereby when said large-format motion picture film is played the information recovered is essentially the same as the information recovered from 35 mm motion picture film to which the normal format of said motion picture soundtrack is applied.