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Deva Timecode is gonna get me sacked


HOPKIN

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I wholeheartedly agree with you Marc. But the issue for me is ive stepped in for another recordist who was using the same method, except he was using a sound devices and there were no problems using autosync. I have done projects in the past where 2 frame slips were acceptable. But these guys are pushing for things to be auto synced perfectly. How do I explain that the recorder im using doesnt do the same thing and that the post need to manual sync and that the cameras now need to have lockit boxes on them with two cables to gen lock and feed timecode?

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Hi HOPKIN. I was on the set of DrWho at the beginning of the summer where D.H. the sound recordist was having reports back from post that their TC was 'slipping'. As I understand his setup: SD 788 was master jamming once to two Alexas in the morning (and probably after lunch) due to cam dept refusing to have lockits on the cameras (!!!). I don't know if they resolved the situation but maybe post houses in Cardiff have got very fussy all of a sudden. It may be worth having a word with D.H.?

Will

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Tried new deva today. Same results. Deva drift 1-2 frames. Suggested to edit to offset deva by 1and a half frames to get a half a frame delay on every take.

Is it a drift or an offset?

If sometimes the sync is right on and the numbers are perfect, and sometimes the numbers are a frame or two out, that's a drift. If it's always 2 frames out, it's just an offset and that is very, very easily fixed.

Editing cannot offset 1/2 a frame, to my knowledge -- whole-frame increments only, no fields.

How do I explain that the recorder im using doesnt do the same thing and that the post need to manual sync and that the cameras now need to have lockit boxes on them with two cables to gen lock and feed timecode?

Ya got me! I have no answer except to rent an SD 788 and see what that does. If you continue using the Deva, just rejam every couple of hours and see if that has an effect.

BTW, is this 25fps or 23.98fps or 29.97? I wonder if that could be an issue.

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This is kinda scary, but also comforting. In these recent years that I've been using the SB3 in exactly John B.'s method I never once relied on the Deva's internal tc generator. I did it because the Deva tc always skipped around when power cycled (to change mirror drives). Now I am thankful that my solution also caused me to not suffer from this problem - I just used version 7.46 for like 9 tc-problem-free months, big whew!

Dan Izen

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Its 23.98 Marc. And Izen I understand that you havent had any problems with timecode as the edit probably autosynced and then checked each take instead of autosync and go. I think the deva is terribly unstable at 23.98 as Howy explained that the stamp on the wav can vary by a frame.

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Its 23.98 Marc. And Izen I understand that you havent had any problems with timecode as the edit probably autosynced and then checked each take instead of autosync and go. I think the deva is terribly unstable at 23.98 as Howy explained that the stamp on the wav can vary by a frame.

My guess is that any time code stamp on a camera can vary by a frame unless you're using gen-lock, since, when the record button is pushed, the camera needs to grab the incoming code somewhere within its 1/24th of a frame duration. I'd be interested in anyone else's take on that.

A single frame isn't that noticable, more than a frame is.

NOTE: In a movie theater, if you move back about a dozen rows (about 48 feet at room temperature), you've delayed the sound by approximately one frame relative to picture. Move back another twelve rows, by another frame.

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Tried new deva today. Same results. Deva drift 1-2 frames. Suggested to edit to offset deva by 1and a half frames to get a half a frame delay on every take.

In this case, the term "drift" is probably not the appropriate term. A "random offset" seems to be what is happening here, which is not related to the accuracy of the sync clock.

Howy mentioned in a post above that firmware version 7.55 addressed a random timecode stamp (start point) offset, similar to what you've described. Since you've mentioned using v7.46, have you tried updated the firmware?

To state that "the Deva is terribly unstable at 23.976" is just not true. FWI, I've used several versions of the Deva recorders on many productions using 23.976 and 48K with no reported timecode issues. Granted, a random 1 frame offset would probably not be mentioned, but continuous drift would. I periodically check the timecode accuracy of the recorders I use (typically Zaxcom and Sound Devices) and they are accurate enough to not require the traditional lunch break rejam.

Glen Trew

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The firmware has been updated but to no avail. Different deva used no improvements. Used two different clockit boxes deneke and ambient ( with tuning ) no change. I understand that a frame differenc is not noticeable. But the biggest problem im having is edit is unable to use auto sync ( which is a rubbish way of doing things) but my predecessor was all good with sound devices. I also understand cameras can be out but why are they always lining up with eachother and the deva aint.

Ive asked edit to send my predecessors work to the dub to check that autosync has actually worked for them. It would be good to double check with another set of eyes.

Also why do most post people believe the sound devices is better on timecode?

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My guess is that any time code stamp on a camera can vary by a frame unless you're using gen-lock, since, when the record button is pushed, the camera needs to grab the incoming code somewhere within its 1/24th of a frame duration.

Yes, that's exactly the way the Technicolor engineers explained it to me. They believed that timecode phase was the culprit, that the video frame shifts a few microseconds in such a way that it sees the next timecode frame number, so it'll occasionally be out a frame or two due to bad reference. This is what torpedoed that famous 3D horror movie project I mentioned elsewhere.

To state that "the Deva is terribly unstable at 23.976" is just not true. FWI' date=' I've used several versions of the Deva recorders on many productions using 23.976 and 48K with no reported timecode issues. Granted, a random 1 frame offset would probably not be mentioned, but continuous drift would.[/quote']

That's my experience as well. I worked on one of Glen's projects in post myself (the pilot for October Road) and sound sync was never a problem, ever. We also did at least one other project, the Miley Cyrus movie, and that was flawless as well. But this was using human beings to sync up, based on visible slate timecode numbers. It was always right, to my knowledge.

I have never heard the phrase "autosync" in post-production, but maybe that's an LA thing. To me, each shot's picture and track are loaded into the timeline one at a time, the assistant checks the slate clap, moves it a frame or two if it's wrong, then moves on to the next take. I don't necessarily expect the cameras or the sound to be perfectly in sync in terms of timecode. My old line in dailies was, "the timecode numbers merely get us close -- the slate clap gets it 100% exact."

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I think inexperienced producers are saying, "but this is supposed to be automatic!"

Assistant editors can be huge whiners. I know of a major LA colorist who got into a yelling match with a fledgling assistant editor on the phone, and said "if I knew as little about your job as you do, I'd be unemployed!" He then proceded to lecture them on exactly how to sync up dailies in the Avid and then slammed the phone down. There were no further phone calls.

I sympathize with the mixer, because he's just trying to deal with the stress and challenges of getting good sound on the set. But timecode is granular, and a 1-2 frame offset throughout the day is not unusual. I bet just checking every single take and then sliding them 1 frame (or 0 frames) would literally take 10 seconds per take. But explaining this to inexperienced, demanding people is fraught with political problems.

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Also why do most post people believe the sound devices is better on timecode?

If you go according to specs, the Ambient timecode clock that is built into all their products, all SD products, and the ARRI Alexa CAN BE TUNED to a finer spec than most others (0.2ppm). Whether or not that actually happens is up to the owners of said products.

This tuning can be done "in the field" using the Ambient Master Clockit, whereas with others (Denecke for example), the unit must be returned to get a tune up - unless you're brave and do it yourself like John Blankenship.

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What slate models are being used?

Glen Trew

DING DING! Older Deneckes have a 1 frame delay in TC of their own!

I also feel like the posties in this situation are being overly picky. I understand that they have a lot to do with 3 cams worth of footage, but they need to understand that outside of a well-set-up stage shoot sync between all those devices will never be perfect all the time, especially if the equipment is being moved around a lot. I can't explain technically why this is, but it has been my experience that this is so. We don't shoot in labs, we shoot in the real world. Please, syncers, cut us some slack, we're there to make the director's movie (sound wise), not do sync experiments. As we say on my teams--"all departments must share the pain".

phil p

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No TC Slates being used.

Why not? That's a red flag right there. Unless you're just using regular dumb wooden slates for a specific reason. (And I know of some A-level directors who don't like timecode slates and feel they're a distraction.)

One key advantage of using a timecode slate on a set shooting digitally is that it will allow the editor to immediately see if the cameras are drifting away from the slate numbers. One assumes the slate numbers and sound numbers will always be 100% perfect.

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DING DING! Older Deneckes have a 1 frame delay in TC of their own!

phil p

WOW this explains the stills I was being shown that had two slates in the same still, the older TS-2b was always 1 frame behind the TS-3... huh! (Good thing that's only the "D" slate!) I'm going to forward this thread to the awesome assistant editor who was really cool and did have to deal with this...

Further proof that I need to know more about the post process! I could have possibly just changed slates.

However, I'm now somewhat confused. You're (original poster) saying you WERE constantly jamming the Deva from a sync box and still it was outputting weirdly? Scary! (I guess I've been okay because I always jam off of the sync box and only use the Deva's tc out once per day to initially jam time & date.

Dan Izen

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Also the DEVA has been around forever now and I dont understand why timecode has just been sorted.

I've had 4 DEVA's, all dating back to The DEVA II. Including a DEVA V, and now a 5.8 & 16. When on the cart I've always used an external TC Clock as my master and that was due to my experiences with my DEVA V early on. It just became habit for me in my set up. Ever since I changed to this the calls stopped, unless I did something funky which was usually operator error.

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I've had a deva 2 and 4 and I have always used them as the master clock. Film, red, Alexa , SonyHd and I have never heard a word about sync issues except for one time on a series they were syncing with the stix and A cam was this giant shot that my boom op was standing next to and B cam was pulling off a long lens shot across a lake at the same time. The delay in the sound reaching the mic caused a delay that threw post off. They said one cam was in sync and the other was out. I said, "obviously not my problem" check the code on the cam.

Then went on to explain a little physics.

Anyway I was hesitant to post on this thread as not to jinx myself but MY devas TC have always worked for me.

Larry

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I'm with John Blankenship (comment #12) on time code sync management. I have been using the same method for several years initially using my Sound Devices back-up recorder as my master clock then happily moving on to Denecke's new GR-2 Master Clock which is a smaller updated version of the GR-1 powered by batteries or ext. power. The GR-2 generates rock solid time code (at all available frame rates) which I feed to both my Zaxcom recorders (continuous jam mode) and use to jam my Denecke slates and whichever sync boxes the camera dept. has onboard their cameras. If I pull a Deva off the cart for insert car work the GR-2 comes with me. I know that many friends and colleagues insist that this isn't necessary however I have seen the drift and/or mathematical errors occur enough that I prefer to stick with a master clock that I am certain is correct no matter what.

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Ive placed an offset of -60ms into the Deva which syncs perfectly or is one frame out. Unforunately the edit are still not pleased with this so im going to have to purchase a 788t ssd. Big blow for me as I dislike having to switch machines as im accustom to the deva but TC has let me down

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I'm going to have to purchase a 788t ssd. Big blow for me as I dislike having to switch machines as im accustom to the deva but TC has let me down

Dude - you are in the very tiniest of minorities that has made such a statement "Deva TC has let me down".

Deva TC is perfectly fine for me and a whole lot of others on this group - and several have mentioned their proven onset TC process to ensure that things flow smoothly.

I think you are absolutely foolish to have post dictate to you that you must make another significant investment and buy another recorder to make them happy. If you don't want to take good advice, presented multiple times, then you are letting yourself down.

I'm getting tired of this thread - and your whining. The Zaxcom Deva is a great machine - the mother of them ALL, BTW.

MF

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