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  • Hey all, just changed over the backend after 15 years I figured time to give it a bit of an update, its probably gonna be a bit weird for most of you and i am sure there is a few bugs to work out but it should kinda work the same as before... hopefully :)

how long do Reds hold frame-accurate sync on their own?

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Ryan Schroeder

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Hi,

I know this has probably been asked many times before - but how long do Epics/Scarlets hold frame-accurate sync on their own once jam synced? I understand they drift a lot if they are off or lose power, but once they are on and jammed, how long before they go a frame out of sync? Any authoritative info on this? Temperature-wise, I'm only concerned about room temp - nothing extreme here :)
 
I haven't found any *authoritative* info, only anecdotal/experiential... And that's usually fairly inconsistent. That being said, it's really easy for an DIT/assistant editor to compensate a few frames once it's brought into the comp, no? In other words, what would require frame-accurate sync over a long period and if it is an *absolute* requirement of the shoot, then getting tc-boxes seems like a no-brainer, no?
 
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It's a three-hour live music performance with 5 Reds. We'll be editing multicam in post, so a autosync in Avid would be ideal... no comment on the budget of the shoot... but if i can find convincing evidence that things *will* drift and we'll be spending more money in post adjusting sync than it would cost to rent tc boxes, then I can sell the case and it'll happen.
 
Ryan Schroeder said:
Hi,

I know this has probably been asked many times before - but how long do Epics/Scarlets hold frame-accurate sync on their own once jam synced? I understand they drift a lot if they are off or lose power, but once they are on and jammed, how long before they go a frame out of sync? Any authoritative info on this? Temperature-wise, I'm only concerned about room temp - nothing extreme here :)
Click to expand...

Here's a real world example:

On The Knick - which shoots on Epic DRAGONs - they do not put lockit boxes on the cameras - they just jam in the morning after booting the cameras up- and the cameras stay on until lunch via hotswap - approx 5.5 hours. They power the cameras off at lunch - then after lunch, boot up and re-jam - remove lockits. They only see between 1-3 frame offset/drift.

What you have to understand is that you will ALWAYS have some drift and/or offset - unless your TC is genlocked with your camera - and your camera's sync setting is set to "GENLOCK" - as not only do you need to sync the crystals/clocks - you need to make sure that each new TC # generated is happening at the same time, in sync, with a new frame being captured by the sensor.

An AMBIENT ACN wireless TC lockit like the TINY LOCKIT - can re-tune the crystal every six seconds over a 2.4Ghz wireless signal with a MASTER LOCKIT or other ACN device - basically eliminating any drift - so whatever offset you have (assuming you are not genlocked to with the TC device) will be consistent over the entire shoot day.

If you are doing multi-cam - you are CRAZY not to use AMBIENT TINY LOCKITs and a MASTER LOCKIT. It is hands down the BEST solution.
 
If dead nuts sync is important then Lock-its, or other 3rd party tech specifically designed for the task is highly recommended.

Haven't used one myself yet, but if I understand it correctly, some models of the OffHollywood OMODs for DSMC2 have an internal sync capability essentially identical to what a Lock-it box does. Mark and his peeps can give you all the specifics.

FWIW, why would people like Mark develop heavy duty sync solutions if the current situation was reliable? As Mike notes, on many shoots the DIT just slips the audio a frame or two when needed and it's no big deal. Some days I stay frame accurate all day, but it's not a given.

BTW, SOP in my market is jam in the morning, re-jam after lunch, then let DIT or post sort it out if necessary.

Cheers - #19

Looks like Mark beat me to the send button ;-)
 
I've done it the same way as the Knick without lock-its, jamming directly from the recorder (jam in the morning, leave it powered until lunch, then re-jam after lunch reboot), and there was slippage, but not enough to worry about. Bare in mind, that was only one-camera, and I had scratch track to sync via sound in case of all-out failure. Conversely, when using TCboxes, soundy usually handles it -- gives you the box off the top and collects at lunch (or in this case, after the show).

With five cameras -- during a live show, all starting and stopping at different times (at the very least to swap mags... or are you rocking 1tbs and/or shooting 10:1?) -- it seems like it'd be far more cumbersome to directly jam, and if it does slip, its slightly more of a pain in the ass to fix across all five cams (and what if a camera jams improperly or doesn't take off the recorder -- I've seen a lot of REDs in the field whose internal clock batteries are dead [including mine], which means one accidental power-down and it resets to "Jan1st, 2000, 0:00")... It's far more set-it/forget-it to just get the boxes, and I don't think they're prohibitively expensive to rent.

If anything, tell them to take it out of post/editorial's budget, since they'll be the ones saving time later on (haha, don't actually say that.)
 
The Tiny Lockits that Mark suggests, seem like the ideal solution for Ryan's project. Going forward, I am very hopeful that one of Mark's OMOD expanders will give me an integrated sync solution that makes managing genlock-sync-TC simpler and more reliable.

Cheers - #19
 
Thanks guys. Ordinarily I'd just say get lock boxes and be done with it, of course - would wouldn't.

This shoot is so low budget and everyone is trying to corners - which sucks, but it's one of those things that's 'worth it,' so I'll let that be.

I've decided to get one lockit box, and during cuts between performances - or every few performances - I'll have a PA come around to each camera and do a a quick jam sync. I figure that should be great.
 
i was on a feature running two dragons. had up to 20 frames of drift within a couple hours. Moved to some IFBs on camera to keep it in sync. that worked well. But for the money grab a few of the tentacle sync timecode boxes. they are very accurate and super low footprint. they are amazing. Glad i invested in them.
 
I have been able to get Tc and scratch audio, from calibrated ERX's, sourced from Nomad, multicam-no problem. It is essential to calibrate the EFX's to the Nomad clock, as there can be significant variance in the ERX crystal

Thank you very much

Fury
 
Ryan Schroeder said:
It's a three-hour live music performance with 5 Reds. We'll be editing multicam in post, so a autosync in Avid would be ideal...
Click to expand...
For multicamera shoots, you really need to jam timecode and genlock reference for true frame-accurate recording, both between multiple cameras and between cameras and sound. Timecode alone is not enough. The Denecke SB-T and Ambient Lockit are both good and reliable.
 
Domenic Barbero said:
i was on a feature running two dragons. had up to 20 frames of drift within a couple hours. Moved to some IFBs on camera to keep it in sync. that worked well. But for the money grab a few of the tentacle sync timecode boxes. they are very accurate and super low footprint. they are amazing. Glad i invested in them.
Click to expand...

dude - thanks for the recommend - these look great. the audio TC feature for SLR's or things like pocket cinema cameras etc. is especially neat.
 
If it's a job where there is a guy to pay attention to lock it boxes great, if not, we re jam every battery change and that seems fine. Protocol since red ones.

Nick
 
I tested my own Scarlet X with the TC Buddy unit and if iirc saw a single frame drift after 9 hrs, at which point I terminated the test, reasoning that we'd have plenty of opportunity to re-jam in the course of the day.

Given what others have said above, your mileage may vary.
 
If you do a multi-cam split between four or more cameras, you will see as much as 1 frame of delay even with cameras that have common timecode. Without a solid genlock reference, timecode phase is going to drift and bad things will happen. The editor can always compensate for it, but every time a camera stops and restarts, the problem will continue. I've seen it go the other way -- a frame early instead of a frame late. It can be very frustrating to deal with in post.
 
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