Sync the Slate..

[Richard Ragon]

Ok, I looks like I failed on my Slate Sync. Usually I take the 702T, run it "free run", and then plug in my slate and sync it up at what ever frame rate the camera is running at..  And, just to make sure, I re-sync about every 4 hours, but I also watch the slate in my monitor, and count the beats to make sure it's very close to my recorder and theres little drifting.

Producer gets a call from the Telecine, saying that the slate is out of sync a lot of the time on most of the shots.. Well, I want to know how I can make this better, as too not screw this up again in the future, so I asked a few questions about telecine.

In the mean time, the producer has a pickup day tomorrow.  So, I asked the telecine, what can I do to "make your job easier".

1)  He says, don't use "control track, use LTC"  No idea on this one..

2)  Run the sync at 30fps.  This is a new one too me.. Perhaps they are doing a 3:2 pulldown, and then trying to sync the sound after they have converted it over, perhaps thats why it doesn't match then?  I thought that I match the camera with the frame rate??

3) Over all the telecine says that because of the mis-sync, they have to process a large part of the job manually.  The telecine is creating DVCAM tapes for the editor.  Since the tapes are at 29.97, I'm assuming this means that 3:2 pulldown is the culprit here.  The editor is going to put the tapes into the editing system, doing the edit, then creating a EDL and giving that back to the telecine where they then cut the final.  I totally understand why people used to do this work flow, but given todays more powerful HD editing systems, doesn't this add unnecessary steps now?  Would it be easier to just telecine the whole thing into D1 tapes, let the editor capture what he wants?  100% digital No EDL needed?

Humm.. I'm just going to have to go over to the telecine corp, and spend the day trying to understand the job they do.. Perhaps it will just make me a better mixer anyway..

Anyone run into this, or been notified of this problem before?

p.s.  I think that I'll run jam sync over wireless tomorrow. I'm assuming that the Denke slate will accept a constant sync connection and stay synced right?  What settings do I do on my 702T and the Denke slate?

Thanks

-Richard

[Sergio Sanmiguel]

Humm.. I'm just going to have to go over to the telecine corp, and spend the day trying to understand the job they do.. Perhaps it will just make me a better mixer anyway..

No doubt about it... Also try to grab some of Wolfs Seeberg's Literature and please READ IT!

BTW you might want to read this from Sound Devices Site:

http://www.sounddevices.com/notes/recorders/frame-offset/

[Richard Ragon]

So ask the telecine and the editor what settings they would like you to use, and then be sure your slate is set to the corresponding frame rate.

He was saying that I used Control Track code, which was incorrect.. I should be using LTC.  I have no idea how to set that..

And, he also says go to 30fps, and set the slate to that also.  Seams odd to me if the cameras running at 24fps??? 

Oh well..

-Richard

[Jeff Wexler]

And, he also says go to 30fps, and set the slate to that also.  Seams odd to me if the cameras running at 24fps??? 

Oh well..

-Richard

The "standard" if there still is one for film at 24 fps is to use 30 ndf timecode --- it has been that way for as long as I can remember when timecode first came into the film world.

-  JW

[Richard Lightstone, CAS]

Richard,

I'm hoping that Courtney Goodin jumps in -- as he knows the ups and downs of the time code jungle.

But I know he would first ask if you are shooting on film or HD? The next question is what was your time code set at?

Your answer to these two questions would go a long way in finding out what the 'problem' is.

Reading your posts makes it seem like this is a 24fps Film project. So both RVD and Jeff are correct -- Time Code at 30NDF.

Your setting of the fsk at 48 or 48.048 is really the decision of the editorial department.

I'm on a television series that shoots on film and we are using the 'age-old' standard of 48k, 30NDF. Other shows require their mixers to use 48.048k at 30NDF. 

These two formats have been explained extensively in threads here as well as RAMPS and elsewhere.

Your difficulty reaffirms the often mentioned need to talk with the Post people before you roll any sound to establish the workflow required.

Good luck,

RL

[John Blankenship]

...In the telecine process your sound gets "pulled down" and the picture gets "pulled up" to arrive at a common frame rate...

Although RVD's advice is right on, his above quoted comment is a bit misstated.  (NOTE:  Rich is a more experienced mixer than I am, so if I'm misspeaking, someone please slap me down and set me straight.) 

The correction to his statement is that the picture also gets "pulled down," not up -- which is why the sound needs to be "pulled down" to match. 

Why is this necessary?

It all goes way back to the days of black and white TV when the television frame rate was 30 frames per second.  This made sense since the power line frequency in the U.S. is 60 cycles per second and could therefore be used as a sync reference, etc.  Then along came color television.  The problem was that there was a tad too much information that needed to be transmitted to make it work within the black and white TV specs. 

The FCC (applying its legendary wisdom) stipulated that color television must be backward compatible with black and white sets.  And that created a dilemma!  What to do?

Well, the engineers found a solution that made color TV viable and met the FCC's dictum.  They found that if they slowed the picture frame rate down just slightly (a tenth of one percent, it turns out), they could cram the additional necessary color information in between each frame.  Viewers with black and white television sets would only have to tweak their Vertical Hold adjustment a little bit and they would be receiving the color signal fine on their black and white television.  Therefore, these viewers could enjoy the programs in the glory of traditional black and white and people who could afford a color television set could impress their friends.

All was well and the universe was in order.

Then came the need to broadcast material that was originally captured on film at 24 frames a second. 

Whoops!

With the one tenth of one percent change, television was now being broadcast at 29.97 frames per second.  Film runs at 24 frames a second.  How do you transfer film to videotape, since partial frames are not an option?  Whoops, is right!

Well, if you slow down the film by one tenth of one percent (which is hardly noticeable), you are then, in effect, transferring those 24 frames onto 30 frames.  Since you're now dealing with full frame increments, that's doable.  Basically, you create six duplicate frames that are interspersed among the other twenty-four.  This is done using a pattern of fields (there are two interlaced fields per frame) known as 3:2 pulldown.

So, now when you play this videotape back, the film on it is actually running one tenth of one percent slower than it was shot.

To match this "pull-down," the sound speed also needs to be pulled down.  Conversely, if you shoot on film, edit on video, and then make a cut from the original film, the post-produced sound will then need to be pulled back up to the original film speed that will be distributed.

I hope this isn't too convoluted an explanation -- and anyone feel free to correct any misstatements.

Hey, at least the FCC managed to make color TV backward compatible.  What are they going to do to make my Block 28 Lectros forward compatible?

JB

[Marc Wielage]

1) He says, don't use "control track, use LTC"  No idea on this one...

Naaa, this is an ignorant colorist who's thinking video, not audio. It's all LTC. Ask to speak to the chief engineer of the post house, or at least the head telecine engineer.

2) Run the sync at 30fps.  This is a new one too me.. Perhaps they are doing a 3:2 pulldown, and then trying to sync the sound after they have converted it over, perhaps thats why it doesn't match then?  I thought that I match the camera with the frame rate??

No. It's generally safe to go at 30ndf with film. If you're shooting tape (including HD), then it's generally safe to go at 29.97ndf. Avoid drop-frame. 2:3 pulldown (which is actually what it's called nowadays) is not the issue; it's that the film is running at 23.976fps instead of 24.00fps. In dailies, the sound is pulled down .1%, which is the difference between 30.00 TC and 29.97 TC.

3) Over all the telecine says that because of the mis-sync, they have to process a large part of the job manually.

That's correct. That means the beleaguered dailies colorist has to slowly inch the film forward until the sticks close, then manually jog the sound disk back and forth to isolate the clap, lock everything together, then back up and lay the scene down to videotape. If you're transferring 150-200 takes a day, this is enormously time-consuming. If the slate is correct, it saves the dailies people at least 20% in wasted time. A typical HD/SD dailies session costs about $600/hour, so it adds up very quickly (at about $7K for an 12-hour day).

I totally understand why people used to do this work flow, but given today's more powerful HD editing systems, doesn't this add unnecessary steps now?  Would it be easier to just telecine the whole thing into D1 tapes, let the editor capture what he wants? 100% digital No EDL needed?

In many cases, the producers need the HD tape for previews, trailers, clips, and other purposes. Adding HD to the session does not add any additional steps; it's just more equipment and more routing (more wires). We typically run at least four simultaneous VTRs, plus the film, plus the sound, during one dailies session. Either the HD tapes or the SD tapes are later digitized for the Avid/FCP editor. In many cases, studios now request digital files on a secure website so they can watch the dailies from their office. As of this year, several studios are going all-HD, to the point where nobody watches standard-def anymore. There's no more DVD, no DVCam, no D1, no nothing -- it's all digital files.

One can make the argument that an assistant editor could sync up the sound more efficiently in an Avid, but the execs want to see dailies starting at 8AM the next morning. Few assistants are willing to start working at 3AM to sync up all the material. Nowadays, I think as many as 4 or 5 different sets of people are viewing dailies, so copies are going to the editor, the director, the producer, the studio, and then the crew for screening.

Also, they have to have the metadata burned into all the files -- scene & take number, audio TC, video TC, film keykode, etc. All of this has to be done at the time the dailies are transferred, so the imbedded metadata exists at all stages of the post process. A human being has to manually enter all this information in, but it can be done quickly and easily while the scene is being recorded (very much like a sound mixer entering the scene & take number on a 744T, a Deva, or a Cantar on the set).

I think that I'll run jam sync over wireless tomorrow. I'm assuming that the Denke slate will accept a constant sync connection and stay synced right?  What settings do I do on my 702T and the Denke slate?

My experience is that unless your wireless feed is very strong, you'll get intermittent break-up and garbage in the slate TC. A little crappy Comtek generally won't cut-it. I personally think the jammed slates work fine, but you need to run some tests beforehand and re-jam every 4 hours (or sooner). Talk to Charles at Denecke and he can run down the set-up for you.

[RPSharman]

Richard,

What we are saying here is... set your 702T and your slate for the SAME frame rate always.

If you are shooting film, and you are unsure what you should set the machines for, then set your 702T for 30ND free run 24hr, this will make your time code the same as time of day, and set your sample rate at 48k.  Set your slate also for 30ND.

If you are shooting video, then you should set your 702T for 29.97ND 48k and the slate also at 29.97ND.

Remember, the slate has the capability of drop frame, so be sure you set it right - '0' is 30ND and '1' is 29.97ND, if memory serves.

If you follow these basic rules, it won't be "wrong" and it'll make it through the telecine/transfer process, but it might not be exactly what post wants.  If you are on a show with specific needs, such as 30/48.048k for some TV shows shot on film, then you can make changes accordingly.

Robert

[John E. Walker]

As I understand it...

Telecine transfers 24 to 30.

30 played at 29.97 will run 0.1% slower.

I use 30 for film shoots, and 29.97 for everything else, including the popular 24p HVX stuff which is 23.976 but must somehow resolve to 29.97.

I forgot to set the TC to 30 on a 16mm short back in May.  The solution: Sample Rate Conversion in a Pro Tools session.  I was tricky and told PT to import my source files as if they were 47952 Hz files (they were actually 48 kHz, 24 bit).  Importing with SRC made new 48 kHz files of all the production audio exactly 0.1% longer (slower).  This worked for our purposes.  Of course, the director is syncing sound without using TC.  While I was at it, I also crushed them down to 16 bit files because the editor is using an old version of Final Cut!

[Philip Perkins]

We've hashed this over a lot of times, and all I can add is that anything going thru telecine in the USA will more than likely want to be at 30 NDF (recorder and slate synced together), whether HD or film.  If the syncing in happening w/o telecine in an edit system, then you MUST talk to whoever is doing this--it may be that the video cam. TC rate is a better choice, but it is dangerous to make assumptions since there are many factors in play.

Philip Perkins

[Richard Ragon]

Outstanding Replies everyone.. Thank you, Thank you.  I'm sure that this topic has been covered, and I appreciate everyone taking the time to cover it again.

Yes, this is a Film Project.  Dailies are being make into DVCAM tapes to the editor.

30ND is what I'll set everything at.

p.s. I was thinking of setting sync via some G2 Wireless units.  Or armed with this new knowledge, just sync it, and double check the sync ever two hours.

Again, Thanks everyone.

-Richard

[Noah Timan]

p.s. I was thinking of setting sync via some G2 Wireless units. 

You don't need them, unless your project requires record run time code.  The problem you experienced was not that the TC clock in the slate was untrustworthy or unstable -- it's that you had your recorder and your slate set to two different frame rates.  As everyone's pointed out, they have to be set to the same frame rate to stay in sync with each other. 

If you have one of the newer Denecke slates, I recommend just leaving it on "Auto Set" -- this way it will simply lock to whatever the incoming code is, and prevent this problem (and prevent forgetting to reset the frame rate with a tiny screwdriver on the slate when you change back and forth between frame rates for different kinds of projects).

[studiomprd]

" on a television series that shoots on film and we are using the 'age-old' standard of 48k, 30NDF. Other shows require their mixers to use 48.048k at 30NDF.  "

since we are discussing SMPTE TC, it is worth noting that DF or NDF really does not apply to 30 FPS, or 24 FPS.

it is also important to realize that DF and NDF are not different "rates", but are counting conventions at the indicated rate (29.97 or 23.976) to keep the count aligned with the clock (the actual time) much as Leap Year (Feb 29) is a calendar counting convention used to keep the calendar in agreement with the orbit of the earth around the sun.

While some systems may accept a "30 FPS DF" indication, but as it is not part of the SMPTE standards for TC, actual results may vary, so beware!!

[Charlie Parra]

You don't need them, unless your project requires record run time code.  The problem you experienced was not that the TC clock in the slate was untrustworthy or unstable -- it's that you had your recorder and your slate set to two different frame rates.  As everyone's pointed out, they have to be set to the same frame rate to stay in sync with each other. 

This is correct. The issue was not the equipment, but how the equipment was set up.

If you have one of the newer Denecke slates, I recommend just leaving it on "Auto Set" -- this way it will simply lock to whatever the incoming code is, and prevent this problem (and prevent forgetting to reset the frame rate with a tiny screwdriver on the slate when you change back and forth between frame rates for different kinds of projects).

This will work as well.I always like to caution people to make sure that the slate is not "tricked" into the wrong frame rate due to excessive jitter in the TC. I have seen this in the newer generation of the Devas. So for example, when feeding the slate (in auto set mode) 30fps TC make sure that the slate flags it as CODE30.

Feel free to contact me anytime if you have any questions or issues.

Best Regards,

Charlie

[Bondelev]

" on a television series that shoots on film and we are using the 'age-old' standard of 48k, 30NDF. Other shows require their mixers to use 48.048k at 30NDF.  "

since we are discussing SMPTE TC, it is worth noting that DF or NDF really does not apply to 30 FPS, or 24 FPS.

it is also important to realize that DF and NDF are not different "rates", but are counting conventions at the indicated rate (29.97 or 23.976) to keep the count aligned with the clock (the actual time) much as Leap Year (Feb 29) is a calendar counting convention used to keep the calendar in agreement with the orbit of the earth around the sun.

While some systems may accept a "30 FPS DF" indication, but as it is not part of the SMPTE standards for TC, actual results may vary, so beware!!

There *is* a 30 DF. It's used for originating on film when the editors want to cut at 29.97 DF (usually TV). It is rarely used, some equipment won't recognize it. It runs faster than real time and when slowed down in telecine it becomes 29.97 DF to match real time.

[Philip Perkins]

There *is* a 30 DF. It's used for originating on film when the editors want to cut at 29.97 DF (usually TV). It is rarely used, some equipment won't recognize it. It runs faster than real time and when slowed down in telecine it becomes 29.97 DF to match real time.

I remember this being a big deal for awhile w/ TCDAT--for film episodics where the editors wanted to cut in DF.  My HHB DATs had a mod done to allow them to record 30DF TC.

Philip Perkins

[studiomprd]

" There *is* a 30 DF."

it is not a part of the SMPTE standard!

" It's used for originating on film when the editors want to cut at 29.97 DF (usually TV). It is rarely used, some equipment won't recognize it."

there have been ,manufacturers' implementations of the DF counting system applied to 30 frame SMPTE TC (making it non-standard!) and thus the code may or may not work on other manufacturers' equipment properly, if at all!  BEWARE: I have personally had major problems with "30DF"

" It runs faster than real time and when slowed down in telecine it becomes 29.97 DF to match real time. "

well, actually it runs at 30 FPS,  but the counting makes it seem faster than real time.

and another thing to add to this discussion is that when TC is non-integer, not only are no frames dropped, but no portions of frames are lost, either: the last frame is completed in the next second, thus creating a need to adjust the counting to make the TC time match clock time.