This is a really stupid idea and quite honestly, it sucks. I don't know how others feel, but the backup SDDS track in my opinion sounds WORSE than just falling to SR. To make matters worse, I sometimes hear some of the channels dropping to the backup track, while the others that are not experiencing a dropout continue playing in the primary track. This is horribly distracting during a show!

Question #1:
How can this backup SDDS track be 100% completely and absolutely defeated at all times? I do not ever want to hear it play again. Like I said before, analog SR sounds better...but in this particular installation, if the SDDS falls back to it's backup track, there are two more digital systems just waiting to "jump in and take over", but that won't happen until the SDDS drops through it's low quality track. Thus, the SDDS will have to be placed last in line of the 3 digital units (pretty much defeating the 8 channel) if this can not be defeated.

Question #2:
Is there a way to modify an SDDS player so that it will function like a SRD unit, in the idea that it will not attempt to resume digital playback until "X" number of seconds after good data is received?

Anyone?

_____________________________________________________________________

"Eight Discrete Digital Audio Channel Capability
Up to eight discrete digital audio channels (L, LC, C, RC, R, SW,
SL, SR) are recorded on the two edges (S&P sides) of the 35mm
film negative stock. The SDDS Recorder System is also capable of
creating six channel soundtracks on the film negative as well.

Advanced Error Correction
The data patterns are Reed-Solomon encoded for error
detection/correction. In addition to this powerful error correction
scheme (termed Blocked Cross-Interleave Reed-Solomon Code,
BCIRC) a unique feature of the SDDS encoding system is the
recording of "back-up" channels of audio data.

SDDS soundtrack information is placed redundantly on both sides of the film to keep the film
playing in digital should damage occur to the film print. The process of switching to the back-up
information is known as digital concealment. To assist in concealment when switching to the
digital "back-up" channels, discrete level codes for the original three channels are encoded along
with the audio data."

_____________________________________________________________________

Somehow, I recall that they did not "split" the data between the P and S tracks. Any film (e.g., damaged edge), lab (e.g., safelight fog) or reader (e.g., tracking, focus) problems would likely be confined to one side of the film, so it would seem more logical to have a complete set of data on each side of the print.

Should be simple enough to cover each track separately and hear/see what you get.

------------------
John P. Pytlak, Senior Technical Specialist
Worldwide Technical Services, Entertainment Imaging
Eastman Kodak Company
Research Labs, Building 69, Room 7419
Rochester, New York, 14650-1922 USA
Tel: 716-477-5325 Cell: 716-781-4036 Fax: 716-722-7243
E-Mail: john.pytlak@kodak.com
Web site: http://www.kodak.com/go/motion

This phenomenon is most noticeable on items like the THX Broadway logo. It sounds as if someone is A/B switching between two EQs where one eq has everything on the highest frequencies completely cut...and only on certain channels! It doesn't happen on every film, but when it does, it is very obvious and highly annoying. (And yes, I've done this test where the film was not even threaded through the analog reader.)

The problem is at it's worst when the reader (2000 series) is threaded "to the red line", as the manual says. When the reader is threaded one perforation less tension, it does not happen near as often and the sprockets of the film are not under so much stress. Actual dropouts to analog are also less frequent (if at all) when threaded one perforation less. Of course, try and demo this to hard headed people and it's like talking to a brick wall.

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The P-side carries the "full quality" information for the L, LC, LS, and SW channels along with a "back-up quality" track for the R, RC, RS, and C channels. The S-side is opposite of this. (Full quality R, RC, RS, and C, backup quality L, LC, LS, and SW) Continuously blocking one or the other tracks would provide for switching to analog if digital info is invalid, but you would be playing four entire channels in the lower quality back-up track at all times. I would not want to watch (listen) to a movie this way. Not to mention that the system would still (if you had a bad reel) jump between analog and digital continuosly, regardless of the length of time valid data is present, unlike SRD.

Are you installing a DFP-2000 or a DFP-3000? If your automation is flexible enough and it is a DFP-3000, you could define a format for SDDS-8, (with DTS & SRD fallback) add an extra cue for 8 channel features, and run the rest of the time in DTS or SRD. This way you would retain SDDS-8 capability and eliminate many potential problems with SDDS-6 tracks. If it is a 2000 (or 2500) you could probably use your little trick you describe in the Tips section to bypass the unit unless you have an 8 channel print. Just an idea.

I've been told that there is a way around this, because the labs supposedly have set up their units in this manner to check the printing. Someone out there must know how this is done!

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If you're correct, I guess my SDDS brochure that identifies the S-track as "SDDS Track" and the P-track as "SDDS Back-Up Track" was written by a marketing person, rather than someone who knew the details of the format. As I said, it would be more logical NOT to split the channels between the two tracks, as any problem would tend to affect one side of the print.

------------------
John P. Pytlak, Senior Technical Specialist
Worldwide Technical Services, Entertainment Imaging
Eastman Kodak Company
Research Labs, Building 69, Room 7419
Rochester, New York, 14650-1922 USA
Tel: 716-477-5325 Cell: 716-781-4036 Fax: 716-722-7243
E-Mail: john.pytlak@kodak.com
Web site: http://www.kodak.com/go/motion

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