Hi to all,
ever wondered how Dolby Digital 5.1 sound is ACTUALLY carried by a 35mm cinema film ?
Turns out the 320 kbit/s DD data stream is encoded onto squares optical grids of about 60 x 60 bits & very cunningly fitted in * between* the sprocket holes !!
The embedded Dolby logo is cute dontcha think ?
A tiny CCD camera in the projector captures each 2.4mm square image, 96 of them per second, so it can be processed into 5 channels of audio.
The other tracks you see are Sony SDDS, L/R stereo analogue and timing pulses for DTS so the CD can be synched with the movie.
Such a multi-format movie can be shown by any cinema in the world and exact copies are made by ordinary, chemical film processing.
Betcha you ALL knew that already ....
....... Phil