Abstract: An analog-digitizer sound system for motion pictures that automatically converts both old and new analog stereo film-sound tracks to digital quality sound. The system eliminates the noise, rumble and hiss from any standard 35 mm analog optical sound track. By simply playing the film through the projector sound head in the normal manner the system automatically converts the analog optical sound tracks to digital format. No special storing of digital data on film is required and no special digital decoder equipment is needed. The system produces noise-free sound, increased frequency response, expanded dynamic range and clarity of dialogue. Film studios will no longer need to maintain a double inventory of digital and analog sound or process sound tracks for noise reduction.