my profile | my password | search | faq & rules | forum home

» Film-Tech Forum ARCHIVE   » Operations   » Film Handlers' Forum   » What happened to Cinema Digital Sound? (Page 2)

This topic comprises 2 pages: 1  2

Author Topic: What happened to Cinema Digital Sound? Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 02-13-2009 07:16 PM                     quote: Louis Bornwasser Sounded OK. . . . .when it functioned at all. Thats exactly what we tell customers that have them too! Thankfully just a few odd 3000's here and there and those are actually pretty darn reliable. Mark  |  IP: Logged Joe Redifer You need a beating today Posts: 12859 From: Denver, Colorado Registered: May 99 posted 02-13-2009 07:40 PM                        quote: Martin Brooks Flatliners, Edward Scissorhands and The Doors sounded really good (in 70mm) Since you distinguished 70mm sounding good, was the bitrate for 35mm and 70mm the same, therefore one could not sound better than the other?  |  IP: Logged Gordon McLeod Film God Posts: 9532 From: Toronto Ontario Canada Registered: Jun 99 posted 02-13-2009 08:44 PM                     the linear speed of the print vs error correction probably made the difference  |  IP: Logged Sean Weitzel Jedi Master Film Handler Posts: 619 From: Vacaville, CA (1790 miles west of Rockwall) Registered: Dec 1999 posted 02-14-2009 10:18 AM                     Some published CDS specifications: FORMAT SPECIFICATIONS * Columns of Data: 180 * Rows of data per second: 32,494 * Track Width 0.102 in (2.59 mm) * Bit size, 35mm (height x width) 14 x 14 microns (0.00055 x 0.00055 in.) * Bit size, 70 mm (height x width) 17.5 x 14 microns (0.00069 x 0.00055 in.) * Sound/picture displacement: Zero frames AUDIO SPECIFICATIONS * Number of Channels: 6 (5 full bandwidth plus 1 sub-woofer) * Dynamic Range: 90dB * Channel Separation: 90dB * Sampling Frequency: 44.1 kHz * Frequency Range: 20 Hz-2OkHz +/- 0.5dB * Total Harmonic Distortion + Noise: <0.1% * Control Channel: MIDI* * Synchronization Track SMPTE Time Code * Film ID Number: ID Data Fields * Bits Per Sample: Equivalent to 16-Bit Linear PCM * Data Encoding: Proprietary * EDAC Strategy**: Uses Reed-Solomon Burst Error Correction with Cyclic Redundancy Check Character Backup. Details Proprietary  |  IP: Logged Martin Brooks Jedi Master Film Handler Posts: 900 From: Forest Hills, NY, USA Registered: May 2002 posted 02-20-2009 03:45 PM                        quote: quote: Martin Brooks Flatliners, Edward Scissorhands and The Doors sounded really good (in 70mm) Redifer: Since you distinguished 70mm sounding good, was the bitrate for 35mm and 70mm the same, therefore one could not sound better than the other? | I dunno. I was just indicating that I saw those films in 70mm and not 35mm. But I think the bitrate for 70mm was higher which is why the first films were released only in 70mm - if I remember correctly they couldn't initially get it to work in 35mm. But I'm sure others will have the tech details to confirm either way.  |  IP: Logged Mark J. Marshall Film God Posts: 3188 From: New Castle, DE, USA Registered: Aug 2002 posted 02-21-2009 09:06 AM                    I seem to recall that the bit rate was the same but the physical bits were bigger. But I could be wrong.  |  IP: Logged Thomas Hauerslev Master Film Handler Posts: 451 From: Copenhagen, Denmark Registered: Aug 2000 posted 02-24-2009 01:38 AM                        Film list Don't forget the demo "Sounds like the real World" - simply spectacular sound I ran "T2" in CDS 35mm - very good sound  |  IP: Logged William Short Film Handler Posts: 5 From: Southborough, MA, USA Registered: Feb 2009 posted 03-15-2009 02:45 PM                        This recent thread reminded me I should dig up some archival materials and put them here for those curious about the early days of what eventually became CDS. In doing so, I don't mean to take away from the fabulous work done by Ron Uhlig and his team at Eastman Kodak and Howard Flemming and his team at ORC. This work was done independently, with their knowledge and cooperation, to get some quick sense of how bad the error rate might be with the small spot size they required on the film. The hope was that some quick and dirty measurements with readily available equipment would give some confidence before building up the specialized recorders and readers needed to do the definitive experiments. I used a test target where the digital data in each column of the row was the same, so I didn't have to worry about tracking the film laterally. I made error measurements when the print was new, and then after several hundred passes through a Century C in a changeover house, spliced into their trailer reel, figuring that would be worst-case. The photos show what the film looked like. No film cleaner in use in this booth (at least not back then). Film travel in all these images is left to right. The top image is a new print, the middle is several hundred passes, and the bottom is the image at a tape splice after several hundred passes. The images look pretty wretched, but the actual error rates were manageable, which encouraged the Eastman Kodak folks and ORC folks in the early days. The next photos show the installation of the prototype CDS system in the screening room at the Eastman Kodak Hollywood sales office. The rack has a booth monitor at the top, three Yamaha stereo DSP units that provided third-octave eq, and then the rest is prototype processor. The prototype CDS reader sits atop the mag penthouse. One of the reasons the processor was so big was that the custom high-performance DSP chip needed for the system failed to meet specs, and so four of these heat-generating power hogs were needed in the processor, rather than one as originally planned. Second generation processors (which were manufactured at least in pilot-run quantities, but I do not know if any were ever installed in theaters) were considerably smaller. All the development work was done on 35mm. The reason to introduce on 70mm was purely a marketing decision, as far as I know. Track specifications were identical for 35mm and 70mm. Spot widths were the same, but spot length was 25% longer in 70mm, due to the faster linear speed of 70mm film. One problem with 70mm was where to put the track. It had to be inboard of the perfs so it could be printed with existing machines, but there wasn't room between the perforations and the nominal projectable image. My recollection is that CDS cheated, and intruded into what nominally should have been projectable area. The photos below compare the CDS data spot size on 35mm to the Dolby Digital 35mm spot size, at the same magnification. The individual spots on the CDS track can't be resolved at this magnification, so the track has a mottled appearance. Here's a view of the CDS soundtrack image from a 35mm print at greater magnification showing the individual data spots.  |  IP: Logged Mike Blakesley Film God Posts: 12767 From: Forsyth, Montana Registered: Jun 99 posted 03-15-2009 08:14 PM                        quote: William Short My recollection is that CDS cheated, and intruded into what nominally should have been projectable area. Really? I always thought CDS used the exact same amount of film real estate as the analog track...? Very interesting pics, thanks for posting them and welcome to the forum.  |  IP: Logged Marco Giustini Film God Posts: 2713 From: Reading, UK Registered: Nov 2007 posted 03-15-2009 08:26 PM                     Very Interesting, thanks William! Marco  |  IP: Logged Sean Weitzel Jedi Master Film Handler Posts: 619 From: Vacaville, CA (1790 miles west of Rockwall) Registered: Dec 1999 posted 03-15-2009 08:31 PM                     The CDS track completely replaced the 35mm analog optical track. However from photos previously posted of a strip of 70mm CDS, the track appears to be printed inboard of the sprockets, intruding on the normal projectable area. FWIW, there was a great discussion about CDS in a previous thread a few years ago: CDS Discussion I am actually in posession of a complete CDS system with two readers and a processor in my home screening room. At this point, however, I have no CDS prints and the processor does not seem to boot up so the whole thing is more of a curiosity piece. Perhaps someday I'll run across a CDS print and see if I can get the system to work.  |  IP: Logged Michael Schaffer "Where is the Boardwalk Hotel?" Posts: 4143 From: Boston, MA Registered: Apr 2002 posted 03-15-2009 09:51 PM                        Probably not because the reason it doesn't boot up is that the CMOS battery is depleted. So the firmware is gone. Oops. I don't think there is any way to get that these days.  |  IP: Logged Sean Weitzel Jedi Master Film Handler Posts: 619 From: Vacaville, CA (1790 miles west of Rockwall) Registered: Dec 1999 posted 03-16-2009 03:30 AM                     I think it's a little beyond firmware. I have power and fans, but nothing on the front display panel. The LCD doesn't even illuminate. I've run across systems that have gone dead due to an expired CMOS battery. fortunately swapping out said battery seemed to resurrect said equipment as the firmware resided on non volatile ROM modules. I only hope the system isn't like old General Instruments Videociper RS modules for Satellite. Once the batteries died in those, the decrytion keys died with them rendering the module useless. I'll have to hunt around for batteries in this processor - perhaps I might get lucky just swapping out the cells... of couse it doesn't matter unless I can find some CDS material. Thanks for all the suggestions.  |  IP: Logged

All times are Central (GMT -6:00)

This topic comprises 2 pages: 1  2

Printer-friendly view of this topic

Hop To: Select a Forum: Category: Operations -------------------- Digital Cinema Forum Film Handlers' Forum Large Format Forum Ground Level Feature Info, Trailer Attachments & REAL Credit Offsets Category: Community -------------------- Film-Yak Film Handlers' Movie Reviews The Afterlife Bob Maar's Joke-A-Thon Category: Classified -------------------- Equipment and Supplies Wanted/For Sale Help Wanted/Seeking Employment Category: System -------------------- Software Beta Testing Forum

The Film-Tech Forums are designed for various members related to the cinema industry to express their opinions, viewpoints and testimonials on various products, services and events based upon speculation, personal knowledge and factual information through use, therefore all views represented here allow no liability upon the publishers of this web site and the owners of said views assume no liability for any ill will resulting from these postings. The posts made here are for educational as well as entertainment purposes and as such anyone viewing this portion of the website must accept these views as statements of the author of that opinion and agrees to release the authors from any and all liability.