This is topic "Cinema Digital" sound in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.
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Posted by David Stambaugh (Member # 1102) on 01-16-2002, 08:47 PM:
Just curious if anyone here had the opportunity to work with Cinema Digital sound in a commercial theatre. I think it was developed by Optical Radiation (what a great name for a company!). I recall seeing Dick Tracy in spring of 1990 at the Edwards "Big Newport" in Newport Beach CA, in 70mm Cinema Digital sound. My recollection of the Dick Tracy show is it was flawless sound-wise.Besides only working on 70mm, wasn't C-D also severely handicapped by not having any analog fallback? A digital failure would mean no sound, period. How did the system perform during its limited commercial application? The format actually had at least one major advantage over current digital sound formats: It supposedly used very little compression. But at that time, they didn't have a 35mm version working yet, and I guess Dolby and others leapfrogged Optical Radiation by coming up with a viable 35mm system first. Thus making "Cinema Digital Sound" an interesting historical trivia question for film handlers I guess.
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- dave
Crab juice, or Mountain Dew?
Posted by Aaron Sisemore (Member # 145) on 01-16-2002, 09:00 PM:
Its CDS (Cinema Digital Sound) and was developed by ORC and Kodak.Both 35mm and 70mm CDS prints of several titles (with the 70mm 'Dick Tracy' being the 'historical first') were made, and yes the major drawback was that there was no analog backup track (the 35mm prints had the CDS track in the space where the regular analog track would go). Unfortunately, the system was extremely unreliable and failed constantly. This problem ultimately killed the format in a couple short years...
I believe Brad has a CDS system in his screening room.
-Aaron
Posted by Ethan Harper (Member # 472) on 01-16-2002, 09:11 PM:
Cds had no ananlog backup because it was printed in place of the analog soundtrack on the film. I have heard some theaters would get 2-3 prints shipped if they played that certain movie in CDS format in case something did go wrong. They did print CDS on 35 and 70 as well.------------------
--"That's my story and i'm sticking to it!"--
Posted by David Stambaugh (Member # 1102) on 01-16-2002, 09:12 PM:
I searched on "cinema digital" before posting, didn't realize the correct acronym is CDS (duh). I see now there's been a lot of discussion about this.
Posted by John Walsh (Member # 168) on 01-16-2002, 11:34 PM:
The "Hollywood" legend I heard (don't know if it's true) is that CDS demo'ed their system to Steven Spielberg. There were problems, so Spielberg said "No way" and went for DTS. Although CDS did fix most problems, it was too late: that demo killed the company.
Posted by Thomas Hauerslev (Member # 566) on 01-17-2002, 02:52 AM:
Bobby Hendesson once wrote this about CDS. A list of the films is here here.
I was fortunate to work with CDS with "T2" in 35mm 10+ years ago. Worked perfectly. Terriffic sound.
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Cheers, Thomas
..in70mm - The 70mm Newsletter
www.in70mm.com www.dp70.com www.70mm.dk www.hauerslev.com http://hjem.get2net.dk/in70mm
Posted by John Pytlak (Member # 331) on 01-17-2002, 07:59 AM:
Steve Kraus' site also has CDS information:
http://members.aol.com/cds3570 ------------------
John P. Pytlak, Senior Technical Specialist
Worldwide Technical Services, Entertainment Imaging
Research Labs, Building 69, Room 7525A
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
Posted by Mark Gulbrandsen (Member # 72) on 01-17-2002, 09:47 AM:
I think the reason it used all of the available space was because it was un-compressed digital data.
Mark @ GTS
Posted by Jack Johnston (Member # 887) on 01-21-2002, 01:26 PM:
I worked for ORC (Optical Radiation Corporation) during the CDS heyday and the reports of field failure were GREATLY over exaggerated to say the least. Yes there were a few failures for this new technology but the 'rumor mill' went to work fast and efficiently to make ORC the "first in/first out" of the digital sound arena. In one field failure of "Days of Thunder" in Westwood, California, the system power supply was backed into a corner blocking air ventilation which lead to the failure regardless of the instruction manual making very specific comment on how to place the supply to allow sufficient airflow.
As reported above from Copenhagen, I was in the theatre the night they played "T2" as the closing film for the very first Copenhagen Film Festival. I worked closely with Steen Larsen (God rest his soul) and the evening ended on a very HIGH note - as the attendees exited the theatre I stood in the lobby..."Yeah good movie, but the sound, it was great" was hearlded from the masses.
CDS fell victim to Hollywood where no one wants to be first but everyone wants to be second. What did they say about the 'talkies' - it'll never last; what did they say about the advent of color: same thing. ORC did have problems but those problems were primarily those of ego for being the first digital system ... the systems, when installed/maintained ran an impressive 96.4% reliability - whatelse in the booth can you say that about?
Posted by David Stambaugh (Member # 1102) on 03-31-2002, 05:52 PM:
Today I found this newspaper clipping, a display ad by Edwards Theatres for the debut of CDS in their flagship location. Kind of a nifty piece of movie trivia, especially as it relates to the eventual widespread use of digital sound (I also mentioned this in my Edwards obituary in the Ground Level forum). 
Posted by Gordon McLeod (Member # 33) on 03-31-2002, 06:08 PM:
Until this xmas I had a CDS ceramic tiled cup coaster
What ever happened with the laserdisk timecode system that strong tried to market in cojunction with a ca based company
I often wondered if it hadn't had its development by the for-runners of DTS
Posted by David Stambaugh (Member # 1102) on 03-31-2002, 06:45 PM:
I vaguely remember that "Fantasia" ran in digital sound at an LA-area theater in the late 80s. I think there was a newspaper writeup about it that talked about syncing the film to a sound source that might have been VHS tape. Does anyone remember the Corvus Mirror backup system? It allowed huge amounts (for its time) of digital computer data to be backed up to standard VHS tape. Maybe this sound system was related to that. I dunno.
Posted by Brad Miller (Member # 2) on 03-31-2002, 07:00 PM:
I think John F. Allen did that Fantasia setup. To my understanding, it was an external digital source (digital tape, cd, etc.) that was sync'ed up to the film. There may or may not have been some form of timecode to keep things locked together. JFA would be the best person to explain the setup.
Posted by Gordon McLeod (Member # 33) on 03-31-2002, 07:00 PM:
That was John Allens use of a digital on video tape I gather it used a shaft encoder on the projector to lock it up
Posted by Bobby Henderson (Member # 840) on 04-01-2002, 12:19 AM:
I'm trying to remember the specifics of the "Fantasia" screening in the 1980's (Widescreen Review had an interview with John Allen some years ago where he went into detail about how they rigged up the setup). Basically it was a separate digital audio reel to reel tape system playing 2.0 channel stereo audio in synch with the 35mm film print.The marketing of the HPS-4000 sound system as "the first in digital" was always kind of a confusing thing since HPS-4000 itself was more akin to THX and not a sound storage/recording process. That's why I always consider Cinema Digital Sound to be the real "first" theatrical digital sound format. It was a complete digital sound delivery system.
I've never been able to find out for sure just what the bitrate was for CDS. I know it was not uncompressed LinearPCM. But even though Delta Modulation does not require as many bits as LPCM, one could argue the audio is not really compressed --at least not in the typical lossy data reduction method used by DTS, Dolby Digital and SDDS. Sony's Super Audio CD format (with its Direct Stream Digital encoding process) uses a more advanced version audio coding like that used by CDS. But they call it Delta Sigma Modulation. I'm not a math wiz or audio engineer so I couldn't break down the specific differences. Judging by the audio quality of CDS, it did sound very very good. I was always impressed by the sound of "Dick Tracy" and am wondering just how good (or not so good) it will be transferred over into Dolby Digital 5.1 with its upcoming DVD release.
Posted by Aaron Sisemore (Member # 145) on 04-01-2002, 01:15 AM:
Laurie Anderson's 'Home Of The Brave' was also done via a VHS-recorded digital track synced to a 35mm print.-Aaron
Posted by John Pytlak (Member # 331) on 04-01-2002, 12:35 PM:
Bobby Henderson said: "I've never been able to find out for sure just what the bitrate was for CDS"The details were given in the SMPTE papers "Cinema Digital Sound -- The Technology" and "Cinema Digital Sound -- System Overview", by Howard J. Flemming and Ronald E. Uhlig, presented at the 132nd SMPTE Technical Conference in October 1990. For 35mm prints, the raw bit rate was 5,850,000 bits per second. Each bit was 14 x 14 micrometres in size, with 180 columns of bits across the track, and 32,500 rows of bits in each second (24 frames) of film.
------------------
John P. Pytlak, Senior Technical Specialist
Worldwide Technical Services, Entertainment Imaging
Research Labs, Building 69, Room 7525A
Rochester, New York, 14650-1922 USA
Tel: +1 585 477 5325 Cell: +1 585 781 4036 Fax: +1 585 722 7243
E-Mail: john.pytlak@kodak.com
Web site: http://www.kodak.com/go/motion
Posted by Bobby Henderson (Member # 840) on 04-01-2002, 09:20 PM:
Holy Moly! 5.8 million bits per second!? That's a lot more data than the loose "4:1" claims on data compression ratio I had heard. That kind of bandwidth is more than double the 2.2 million spots total per second used by SDDS (and only 1.2 million are used in the primary soundtrack for SDDS). CDS' 5.8Mb/s is actually more than the 4.6Mb/s needed for a 16-bit/44.1kHz audio track featuring 6 full bandwidth channels. But I am assuming all the extra data is needed for error correction.Those fellows at ORC sure had some guts by printing digital audio tracks with that much data. Limits on film printing certainly introduced problems, but CCD imagers back in 1990 were nowhere near the level of sophistication and speed we see today. It kind of makes me wonder how reliability would be improved with a new CDS reader designed with current CCD electronics.
Posted by John Pytlak (Member # 331) on 04-02-2002, 07:18 AM:
I recall that Kodak's Ron Uhlig worked closely with film laboratories to assure that the CDS tracks could be printed reliably. Putting the bits in the analog soundtrack area minimized any wear during projection. The lack of analog backup and the dual print inventory issues were problematic. Yet CDS paved the way for today's digital sound systems. ------------------
John P. Pytlak, Senior Technical Specialist
Worldwide Technical Services, Entertainment Imaging
Research Labs, Building 69, Room 7525A
Rochester, New York, 14650-1922 USA
Tel: +1 585 477 5325 Cell: +1 585 781 4036 Fax: +1 585 722 7243
E-Mail: john.pytlak@kodak.com
Web site: http://www.kodak.com/go/motion
Posted by Steve Kraus (Member # 476) on 04-02-2002, 06:55 PM:
The raw bit rate (180 x 32,494 = 5,848,920 b/s) includes Reed-Solomon error correcting codes which adds quite a bit of overhead. The CDS specs claimed the main channels were the equivalent of 16-bits/sample, 44.1K samples/sec. That works out to 3,528,000 bits per second. I'm not sure about the sub channel but let's say it's half the sampling rate and half the bits per sample. That brings us up to 3,704,800. Add some auxilary data bits and the error correcting code makes up the balance.
Posted by Joe Redifer (Member # 3) on 04-02-2002, 08:25 PM:
Here is a picture of the HUGE CDS reader. This thing weighs more than you do.
And below is the only picture I could dig up of the massive "rack mounted" decoder (the grey unit). It bears many similarities to SDDS, actually.
One time Brad and I actually got this thing to boot up. It was an amazing moment! Nowadays this same technology could be built to be 1u high! Maybe 2u if you really need all those buttons.
Posted by Brad Miller (Member # 2) on 04-02-2002, 10:42 PM:
Huge is hardly the word for CDS. Joe isn't kidding about how unnecessarily heavy that reader is. I'll try and remember to take some pictures of the guts of the processor and reader and post them soon.
Posted by Steve Kraus (Member # 476) on 04-03-2002, 08:49 AM:
THE Actual Joe Redifer said:
>It bears many similarities to SDDS, actually.I believe Howard Fleming of CDS was the primary designer of SDDS. As for the reader, they designed it they way they thought a projector penthouse ought to be designed starting with a cast metal housing just like a 6 or 4 track magnetic penthouse.