24 F Jam Sync Out of Sync in Latest Firmware Release at DVinfo.net

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Old December 4th, 2009, 07:29 PM   #1
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24 F Jam Sync Out of Sync in Latest Firmware Release

Hi Mike:
Please be advised the Jam Sync Feature in 24 F looses sync by over 5 seconds in one hour between camera 24 F clock and XDR 24 F clock. I would say the Jam Sync is much more accurate then it was before, and certainly is holding much longer before drift commences, but over 5 seconds in a one hour concert shoot could be disastrous. I will now check Jam Sync at 59.94 i. EDIT: I will repeat the 24 F Jam Sync test to see if my results are repeatable.

Respectfully,
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Old December 4th, 2009, 08:23 PM   #2
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Hi Mark-
Thanks for the feedback, we will check out ASAP and report back.

Best-
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Old December 4th, 2009, 10:23 PM   #3
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Jam Sync @ 59.94 i

Hi Mike & Tommy:
OK for Jam Sync @ 59.94 i setting. One hour and a half in perfect sync to the frame as far as I could tell visually. Retesting 24 F Jam Sync to see if malfunction is repeatable.
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Old December 5th, 2009, 12:38 AM   #4
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Second Test of 24 F Jam Sync from Firmware 1.1.151

Hi Mike & Tommy:
OK, I've done a repeat test of 24 F Jam Sync, and after 3 hours there is an 8 second drift (Behind) XL H1 24 F TC clock. Test was performed from Jam Sync H1 TC clock in "Free Run" mode. Behaviour of malfunction is as follows....

1. TC Jam Sync locks for about 15 to 20 minutes, then seems to progressively drift to a point of 8 seconds *Slower* than reference TC clock (Camera), then remains more or less consistent at this rate of drift.

2. This anomaly is repeatable.

3. TC rate of drift is considerably less than with the previous firmware release.
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Old December 5th, 2009, 02:50 AM   #5
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Wandering Sync.....

I would be cautious about jumping in to blame the 'wandering sync' on the XDR/Nano. It could well be that it's the camera that is going adrift. When using 'time of day' with multiple cameras and seperate audio recorder, we always use Lockit boxes and jam them to the Audio Devices recorder, then mount those on the cameras. Good luck in sorting it out.
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Old December 5th, 2009, 11:12 AM   #6
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Wandering Sync Issues

Hi Godfrey:
I'm not "blaming" I'm reporting. Let's try and keep the passion out of this analysis of the problem as much as possible. Without prejudice, I posed the exact same question about which one could be drifting, and logic dictates if it was the camera, then how do you explain perfect Jam Sync @ 59.94 i ?????

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Old December 5th, 2009, 12:53 PM   #7
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Are both cameras aimed at a time source that they are burning into the recorded picture also?
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Old December 5th, 2009, 01:14 PM   #8
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Test Criteria

Hi Aaron:
My test criteria was rather primitive. All I did to ascertain what the Jam Sync functions are doing is to place my XDR screen right next to my open XL H1 viewfinder and determine by visual inspection if there is any "drift" in the two clock readouts. When camera and XDR are set to 59.94i there is no discernible drift I can see by visual inspection of the two clocks even after 2 1/2 hours. When the same test is repeated @ the 24 F setting on the XL H1 and 3:2 pull down removal is set on the XDR, as well as TC drop frame carefully enabled on both camera and XDR, then XDR clock begins to drift after approximately 15 minutes and seems to slow down by a factor of 8.5 seconds, then hold at this rate after 4 hours. It is interesting to note that the drift seems to stop its progression at about 8.5 seconds in variance. (???) I don't know why that is. In theory it should continue a slow but steady progressive drift. Perhaps it is possible that the internal processor of the XDR has to do *more* work in performing 3:2 cadence removal, and it is due to this extra processing time - that the XDR clock slows down. (**This is pure speculation on the part of the tester and he has no firm data to back that up - Just a hunch.)
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Old December 5th, 2009, 01:30 PM   #9
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Oh I see. Well now I'm extra glad that I don't need to do 3:2 pulldown removal :-)
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Old December 5th, 2009, 03:41 PM   #10
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Dear Mark,

We appreciate the thorough testing that you are doing.
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Old December 5th, 2009, 07:11 PM   #11
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Mark The Happy Tester

Hi Dan:
You are most welcome Dan and I'm happy to make this product a better one if I can. I like to test stuff out thoroughly before I use it on a shoot. I think CD revisions are moving in the right direction with the 24 F Jam Sync fixes, because the drift is less now. Perhaps the next update will get it bang on. 59.94 i *is* bang on :-) I think this fact makes regular TV shooting in ATSC HD formats with Jam Syncing Perfectly safe and OK with the XDR.
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Old December 5th, 2009, 07:14 PM   #12
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Master Clock Jam Sync Both Camera and XDR ?

Quote:
Originally Posted by Aaron Newsome View Post
Oh I see. Well now I'm extra glad that I don't need to do 3:2 pulldown removal :-)
Aaron: Do you have a Deneke TS-1 or later model electronic Time Code Slate ? If you did, then you could use the TC clock in the slate as a master source and jam both the Nano and your Viper from it (Or do you have an XDR ?). Then you could capture to CF card and we could study the sync versus the Master TC Clock.
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Old December 6th, 2009, 09:37 PM   #13
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I'd love to have one of those slates but trust me, I do not own anything to sync TC with at all so I won't be testing this feature anytime soon.
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