Film-Tech Forum ARCHIVE: CDS Digital Sound

This is topic CDS Digital Sound in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Andy Davis (Member # 262) on 01-26-2000, 01:43 PM:

What happened to CDS sound? Was the digital data encoded onto a CD or on the film?

Posted by Ian Price (Member # 14) on 01-26-2000, 02:04 PM:

CDS was encoded on the film in the area that was the analogue soundtrack. CDS sounded great. The only problem was that when the digital failed there was no backup analogue track. They used to send each theatre a 2nd analogue print for emergencies.

I ran The Doors on 35 mm at the Coronet in Los Angeles for a week. It was great. Then we ran T2 in 70 mm at the Continental in Denver. The soundtrack failed after a couple of weeks and I never heared about CDS Digital again.

They had to have two kinds of prints, CDS and analogue. The industry hates duel inventory. Afew years later I was opening Downtown Plaza in Sacramento. We had 7 old movies we were running for the public for free. One of them was T2. I built them up in a hurry because we had no time. I hit the screen and the sound was Shuuu..... The first reel was CDS.

Bobby Pinkston was the fellow who ran the CDS program at ORC. He is now with Dolby.

I do have one CDS poster in my office as a reminder.

Posted by John Pytlak (Member # 331) on 01-26-2000, 02:29 PM:

In the mid-1980's, John F. Allen demonstrated digital sound in a theatre environment by interlocking a projector with a video recorder playing PCM digital sound. Showings of "Fantasia" with digital sound were very successful, but this "double system" was not considered commercially viable for large releases.

Cinema Digital Sound (CDS) was the first commercial system to print a multi-channel digital soundtrack (bits) directly on the film. It was a joint project between Kodak and Optical Radiation Corporation (ORC). To a large extent, it led the way in convincing film makers, distributors and exhibitors that digital sound was viable in theatres. CDS was used for both 35mm and 70mm prints. The first major release was "Dick Tracy" in June 1990.

For 35mm prints, the CDS track was printed in the "protected" area used for analog sound, to wisely avoid projector abrasion and wear of the digital data. But by eliminating the analog soundtrack, "dual inventories" of prints were required, and there was no analog backup if the digital sound system failed. Some early (fixable) hardware problems gave CDS a "black eye" when the system failed without having analog backup. By 1992, Dolby and DTS came out with their systems, and CDS became history. It's "failure" was really a success story for film, as CDS paved the way for today's digital sound systems.

Perry Sun's "Movie Sound Page" has a good description of CDS written by Bobby Henderson. Here is the link:
http://www/moviesoundpage.com/msp_cds.htm

Another private web page has the original CDS brochure, specifications, and photos:
http://members.aol.com/cds3570/

------------------
John P. Pytlak, Senior Technical Specialist
Worldwide Technical Services, Professional Motion Imaging
Eastman Kodak Company
Research Labs, Building 69, Room 7419
Rochester, New York, 14650-1922 USA
Tel: 716-477-5325 Fax: 716-722-7243
E-Mail: john.pytlak@kodak.com

Posted by John Pytlak (Member # 331) on 01-26-2000, 02:39 PM:

OOPS! :0

I mistyped the CDS link on Perry Sun's Movie Sound Page:
http://www.moviesoundpage.com/msp_cds.htm

Posted by Michael Barry (Member # 237) on 01-27-2000, 09:06 AM:

Apart from 'Dick Tracy', wasn't 'Final Approach' one of the first, if not the first CDS release? Or was it just the first all-digital sound stem feature film?

Although most people I've spoken to (of the ones who remember it!) dislike this film, I thought it was remarkable, and I still think about it. Unfortunately, there was no theatrical release of the film in Australia, because I kept imagining how great it would have been on a large screen with CDS sound. Instead, I saw it on Laserdisc. I had no idea what kind of film to expect and was very surprised - I thought Hector Elizondo was brilliant.

Posted by Martin Frandsen (Member # 74) on 01-27-2000, 10:10 AM:

The 'moviesoundpage' has some good reading stuff about CDS. 'Dick Tracy' was the first 70mm film to have CDS, later came the 'The Doors' which was the first 35mm film to have CDS encoded!

WHY did they have to place the CDS track were the optical track is? Was it not possibel at that time to place it were the Dolby Digital track is today? That way we could have had CDS today insted of Dolby

Posted by John Pytlak (Member # 331) on 01-27-2000, 02:46 PM:

It is well known that the edges and perforation area of the print are abraded by certain projector components. Most good equipment designs take great care to minimize any abrasive contact with the picture or analog soundtrack area of the film. Cinema Digital Sound took the "good engineering" approach of printing the digital data where it was least likely to be abraded or damaged, which was in the already "protected" analog soundtrack area.

Projector wear and abrasion can be a problem with digital tracks printed along the edges or between the perforations of the film. Sooner or later, enough damage will occur to cause data error rates to increase. A proven way of reducing projector abrasion is proper print lubrication, per Kodak's processing specifications (H-24.02, H-24.09) and SMPTE Recommended Practice RP-151. Unfortunately, edge-waxing is rarely done anymore because of environmental restrictions on the solvents used to apply the wax.

The design, materials, and finish of the projector gate and sprocket shoe greatly affect projector wear. Proper cleaning and maintenance (alignment, tensions) of the film path is also very important to reducing projector abrasion, and the dusting/flaking of prints.

Posted by Gordon McLeod (Member # 33) on 01-28-2000, 02:17 PM:

A interesting approached was proposed by the National Film Board of canada and published in a older SMPTE journal (i forget the date) that used a beam splitter to defract the interefence pattern of the digital data into a seperate CCD camera and the regular optical track printed under it in to a solar cell

Posted by John Pytlak (Member # 331) on 01-31-2000, 09:30 AM:

I was not involved with the CDS program, but I understand that the most hardware problems had something to do with overheating. That sounds like something that is fixable.

Posted by David Kilderry (Member # 142) on 02-05-2000, 09:08 PM:

A lesson here for the cinema industry as it looks at digital projection. The first to jump and commit to a digital projection system may well be hung out to dry with well engineered equipment that nobody else picks up.

CDS did the tough initial breakthrough stuff only to have Dolby, DTS and SDDS make the money.

Posted by Stefan Scholz (Member # 147) on 02-06-2000, 03:31 AM:

Some brains, that initially designed CDS, later on "perfected" the system for a different company, a system currently in use and called SDDS.

Posted by Gordon McLeod (Member # 33) on 02-06-2000, 04:48 PM:

Hopefully SDDS meets the same fate as soon as possible