This is topic SDDS Drop-out in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.
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Posted by Ken Lackner (Member # 1002) on 11-24-2001, 02:20 PM:
Do both SDDS tracks contain the same info, or are they different? If you use the kind of cue tape that you fold over the edge of the film, or if you use CPI's edge marking tape, you will be completely covering the SDDS S-track. How long until the SDDS drops out?(Dolby Digital is 4 data blocks before it drops out, right?)
Posted by Brad Miller (Member # 2) on 11-24-2001, 02:41 PM:
I've used a 1 inch (5 perf) piece of white Artist's tape across the entire frame to make a splice with (not for a real show, just to prove a point) and had no dropout in SRD or SDDS. I don't know what the limit it, but if your readers are lined up properly, there shouldn't be a problem.
Posted by Bobby Henderson (Member # 840) on 11-24-2001, 06:48 PM:
Both Dolby Digital and SDDS can miss up to four frames worth of data before faulting out to the analog track (or in SDDS' case, the half-quality digital track and then analog track). Both systems have a lot of data redundancy built into their tracks. Dolby Digital for instance operates at 320kb/s, but there is actually 556kb/s worth of data being read every 24 frames. The primary digital track for SDDS operates at 1.2 million bits per second, but a full 2.2 million bits of data are printed every 24 frames.Still, it is a good idea to make those splices as clean as possible since you never really know just what portions of backup data are being eliminated in between splices.
Posted by Richard Topping (Member # 871) on 11-25-2001, 01:04 PM:
SDDS has differant info' printed on the 2 sides. Soundtrack Side has Centre, Left Centre, Left and Left surrounds as well as a back-up track which is a mix of the Right Side in case's of DCM (digital concealment mode)). The Picture Side has Sub, Right Centre, Right and Right Surrounds as well as a back-up track which is a mix of the left side. The 2 tracks are printed 17.3 frames away from each other. I usually only cover 3 perfs on emulsion side for a reel marker, but have known both tracks to be covered without any drop out.
Posted by John Pytlak (Member # 331) on 11-26-2001, 12:03 PM:
I recall there was a thread on this very subject in July 2001. Al Barton of Sony joined the discussion, and offered to have his technical people answer specific questions.------------------
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 Ken Lackner (Member # 1002) on 11-26-2001, 12:51 PM:
Thanks, John. Was that the thread entitled "SDDS backup track defeat"? Too much technical info that was over my head! I simply want to know that if I use cue tape or CPI's edge marking tape, will it affect SDDS?
Posted by James R. Hammonds, Jr (Member # 673) on 11-26-2001, 08:11 PM:
No, it shouldnt.
I use cues all the time that fold over the edge with no problem.
Also,b back in my days of solid yellow splicing tape there were no dropouts.
Posted by Ken Lackner (Member # 1002) on 11-26-2001, 10:31 PM:
Thanks, that's all I needed to know 