Abstract: Extra high quality or ultralong digital audio channels with an aggregate data bit rate that exceeds the maximum data bit rate for a digital storage medium, such as a CD, laser disk or digital audio tape, are recorded on the audio medium. The recording is accomplished by compressing the data bit rates of the multi-channel input signals so that their aggregate data bit rate after compression does not exceed the maximum for the storage medium, multiplexing the compressed audio signals, encoding the multiplexed signal into a predetermined format, and recording the encoded signal on the storage medium. With the storage medium configured to store audio samples having a predetermined number of bits per sample, the compressed audio signals are multiplexed into data groups having the same number of bits, thereby emulating a normal input to the storage medium, even when this involves dividing various input samples among different data groups.

Abstract: Dynamic range and passband problems in cinema sound transmission are solved by using a laser disk (9) read by a laser disk player (10, 11, 12) synchronized (14) with the original sound track of the film. Problems relating to splices in the film are solved by reading the sound in advance, in storing it in a memory (13), in reading it back subsequently from the memory, and, where necessary, in causing the memory read back system to jump (24) in order to avoid reproducing sound that corresponds to images that have been removed from the film.

Abstract: A digital sound system for motion picture films employs a digital time code on the film to trigger the transfer of sound data from a digital audio store to a FIFO memory. The digital audio data is read out from the FIFO memory and played back in the theater at a constant rate, with any jumps in the digital time code handled by making a corresponding jump within the digital audio store but not in the FIFO memory. Readout from the FIFO memory and clocking of the digital-to-analog converters (DACs) used for theater playback is synchronized to the AC mains that powers the theater projector, and thus allows for an uninterrupted audio playback even if time code entries on the film are obliterated. The FIFO memory need only have enough capacity to accommodate the maximum audio store access time, and can be quite small.