The Format
Sony designed SDDS exclusively for motion picture theatres, there is no consumer equivalent.
SDDS is the only motion picture sound format to offer up to 8 channels of discrete, clear, crisp, vibrant digital sound.
| Soundtrack |
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| The soundtrack consists of an array of microscopic
dots (or pixels) much like those recorded on a CD. With SDDS, both
edges are used to provide two continuous streams of data interleaved
using a cross-redundant error correction technique to further prevent
drop-outs from film damage or scratches. |
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Reader
The SDDS reader is mounted on top of a 35mm projector. The film is threaded through the reader before it passes through the picture aperture. As the film runs, red LEDs are used to illuminate the SDDS soundtrack. Special integrated circuits—called CCDs (Charge Coupled Devices) — read the SDDS data and convert the stream of dots on the film into digital information. This information is pre-processed in the reader and passed on to the SDDS decoder. |
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Decoder The SDDS decoder is installed in the sound equipment rack. The decoder receives the information from the reader and translates it into audio signals routed to the cinema's power amplifiers. The decoder is responsible for a series of processes that must be performed before the audio is recovered. Next, errors caused by scratches or damage to the film are corrected using redundant error recovery data. Since SDDS is read at the top of the projector, the data is delayed slightly to restore synchronization with the picture. And finally, adjustments in tonal balance and playback level are made to match the specific auditorium's sound system and acoustics. SDDS is designed to process sound entirely in the digital domain, bypassing any existing analog processor, preserving clarity and providing full dynamic range. |
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