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Sync drift - am I doomed?
Old 23rd November 2009
  #31
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Jfriah's Avatar
 

Quote:
Originally Posted by bradhebert View Post
As I feared, our unorganized post workflow has turned into a big sync problem.
Another case of the 7 P's.


PPPPPPP

coming to life.



For those unfamiliar:
Piss Poor Planning Prevents Proper Post Production

-Jeff
Old 23rd November 2009
  #32
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Quote:
Originally Posted by philper View Post
To be clear--the 702T DOES have 23.976, but they call it 23.98 to save a digit in the display.
Flame on.

General discussion: Such a problem in today's gear design and the users that get used to talking the talk. I talk with some folks and they say "24" when they mean 23.98 when they mean 23.976. If someone threw Pi at you (the general 'you') would you say 3.1? Idiots...and laziness.

Flame off.

-Jeff
Old 23rd November 2009
  #33
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Quote:
Originally Posted by bradhebert View Post
This is all new to us. First film, DIY. To be honest, the crew pretty much consists of the director, the editor (who shot most of it) and myself (all post audio engineering).

Considering this, the production value is actually quite high... except for the technical problems that I'm trying now to fix.

So, how would you recommend proceeding at this point?
...hand it back to them?
(partially in-jest. Been there... And those technical problems you (YOU!) are trying to fix now ('fix it in post')...aren't such small problems are they?)

As you know, part of our job is education.

As Gary Rydstrom said:

"If we do our jobs well and throw in a little evangelizing, we can make sound as important a part of filmmaking as it should be."

About to start work on a project, myself, that is going to be a complete shootstorm. Shot in the summer, all DIY, and I have another 2 months to mentally prepare/take some zen classes.

Good luck. Glad you kinda figured out how to get through it!

Quote:
Originally Posted by bradhebert View Post
I'm guessing that when I give the editor my mixdown, it will sync up in his Final Cut - even if his project is 24fps? I believe it worked last time (without us realizing I was working on a 29.97 file).

I hope one day to really understand why frame rate changes my sync in Pro Tools, but I can mix to a different frame rate than the editor and it will be in sync when I give them my mix. Basically, why does the frame rate change the duration of the movie in Pro Tools? It seems the video would be the same length no matter what frame rate.
Your answer should be: the editor didn't care when you were having problems, so.........when you send it back...
(chuckle)
And, frame rate doesn't change duration. It is just a frame COUNT. How many frames-per-second...

-Jeff
Old 23rd November 2009
  #34
Gear Maniac
 

Quote:
Originally Posted by Jfriah View Post
And, frame rate doesn't change duration. It is just a frame COUNT. How many frames-per-second...
Right, and that's why it confuses me. The video track in PT changes to whatever frame rate the video file on that track is. It seems like the "real time" that my audio is running would match up even if I replaced the video with a version that only had 2 frames per second.

I've read quite a bit about frame rates and pull ups and pull downs and pushups and all that. I just have never been able to integrate it as a visualization in my mind very well - I certainly learn better by "doing" and maybe now that I've experienced this I will understand it better next time I read about synchronization.
Old 23rd November 2009
  #35
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JSt0rm's Avatar
the 24p fcp session will drift. So you will need to (or they need to) do a pull up to make the audio faster by .01%
Old 24th November 2009
  #36
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Henchman's Avatar
The big lesson here?
Never do audio at 24fps.
Old 24th November 2009
  #37
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Quote:
Originally Posted by Henchman View Post
The big lesson here?
Never do audio at 24fps.
Then I guess we did a good thing by accident!

But it sounds like the master audio mix will still needs a pull down when conforming back to the 24fps video?
Old 24th November 2009
  #38
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Quote:
Originally Posted by bradhebert View Post
Then I guess we did a good thing by accident!

But it sounds like the master audio mix will still needs a pull down when conforming back to the 24fps video?
No, what I meant, was make sure that the pic you get is done at 29.97 or 23.98.
And the audi is as well.
Old 24th November 2009
  #39
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Quote:
Originally Posted by bradhebert View Post
Just to be clear:

The footage was shot 24fps. The editor is editing in 24fps. He accidentally sent me a 29.97fps DV file that I did a rough mix for. Now there have been a few changes to the cut and I need to import a new video file.
If the film was positively shot at 24.00 and the release will be at 24.00 and all other processes are done at 24.00 it makes absolutely no sense for you to work at a pull-down rate.

Why enter the insane NTSC-based area when you are lucky and all is done at true 24.00?

(beware: FCP can play different frame rates in the same time-line, so just because it´s in sync in the NLE it doesn´t mean it will be in sync on the final medium.)
Old 24th November 2009
  #40
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Quote:
Originally Posted by Henchman View Post
The big lesson here?
Never do audio at 24fps.
Why? I do this every day. Film is shot at 24.00, edited at 24.00 and released at 24.00. Why convert to a pull-dow rate in between?
Old 24th November 2009
  #41
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Quote:
Originally Posted by Jfriah View Post
Flame on.

General discussion: Such a problem in today's gear design and the users that get used to talking the talk. I talk with some folks and they say "24" when they mean 23.98 when they mean 23.976. If someone threw Pi at you (the general 'you') would you say 3.1? Idiots...and laziness.

Flame off.

-Jeff
You call people who say 23.98 idiots? What are you then when you say 23.976 when it´s actually

23,976023976023976

;-)

Seriously: 23.98 is perfectly common for 23,976023976023976 just as 29.97 is for 29,97002997002997

Or do you spell out all digits of Pi when you talk about Pi in the street?
Old 24th November 2009
  #42
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No, re-read it. I call people who say "24" when it is (whatever you would like to call it, 23.98, 23.976) ___.


Moreso; it was a slam at the designers for not having "a" number system.
As long as we in-the-biz are clear between 24 and not-24.


And re: pi...as long as it is apple.

-Jeff

Old 24th November 2009
  #43
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Quote:
Originally Posted by Jfriah View Post
[FONT=Arial Narrow]No, re-read it. I call people who say "24" when it is (whatever you would like to call it, 23.98, 23.976) ___.
thanks for clarifying.
Old 4th December 2009
  #44
Gear Maniac
 

My mix appears to sync perfectly back onto the Final Cut project. I didn't have to do any kind of pull down.

I can't tell you how happy I am about this.

I would have felt so alone without this forum. I have yet to find any place as helpful as Gearslutz for post audio (including Digidesign User Conference).

Thank you!

The only problem is that my 2-pop doesn't line up exactly with his flash frame. It's less than a frame off. I'm guessing the rest of the audio is where it needs to be.
Old 7th December 2009
  #45
small side note... this slightly out off sync condition will happen almost every time. The reason? If you do everything in complete perfect sync and then simply print the mix there will be a few milliseconds of delay from any number of things that normally are used in final outputing....
1. Plugins
2. hardware ( output from DAW )
3. hardware ( input to DAW )
etc

After you print a mix, you can place it back in your DAW and slide the entire mix the few milliseconds or subframes so that the 2 pop in the printed mix lines up with the 2 pops in the various unmixed tracks....

As an example my mix stems go out from my protool rig thru an SSL D/D digidesign interface into a euphonix D/D IO into the console , get mixed and then out of the console back thru a euphonix D/D IO to the SSL D/D IO and into protoools.... there is very small delay in all this.

After moving your printed mix files back in perfect sync, ( IE: the leading edge of the printed 2 pop is right on the leading edge of the frame ) trim the front of the files back to the leading frame edge.

This tiny delay or out of sync condition will vary system to system. You won't necessarily hear it or notice it on playback, but its there, and if you are as annul about this stuff as I am, you'll fix it.

cheers
geo


cheers
geo
Old 14th May 2010
  #46
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cgraye's Avatar
 

Ok, I've got a question in a similar vain…

About a month ago I was doing post-production for a short film and in my communication with the film composer, I discovered that he was using an older version of Digital Performer that lacked 23.976 FPS support and he therefore was using 29.97 FPS. The reference movie that we were both working from was 23.976 FPS.

I feared that his deliverables would not sync to picture in my Pro Tools session. To my surprise, everything synced without a hitch at all, which makes me realize how unsure I am about all these frame-rate/time-code particulars.

Please someone correct me if I am mistaken, but I arrived to the conclusion that these session settings in DAWs do not matter (outside of the realm of time-code?) so long as the video that the DAW is referencing is at a particular frame-rate and everyone is working off the same reference video. I somehow believed that the DAW may play back or import the movie and make it match the session frame-rate.

I do not understand the advantage of added frame-rate support, like say in the newer versions of Digital Performer. What exactly do they do for composers? Is it just for time-code?

Any insights greatly appreciated.
Old 14th May 2010
  #47
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23.976 and 29.97 should play well together.

Keep in mind, especially for music, "seconds are seconds" and it is just a different number of frames in those seconds.

You're working in Pro Tools--

Create a new session in 29.97ndf. (to make it easier, make the session start the same as your picture file start, ie: 00:58:00:00 or whatever it is) Go to the 01:00:00:00 mark. Highlight a frame and use signal generator to create a 1 frame blip. Then pull your reference movie in, which is 23.976. Notice anything?

Now switch your session to 23.976. Your blip file didn't move, the timecodes just changed their display times.

The composer is giving you files-only, correct? You're not chasing a tape machine to play back cues?

And the composer will tell you if he/she attends final mix and sees anything that doesn't seem to line up.

Jeff
Old 15th May 2010
  #48
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cgraye's Avatar
 

Quote:
Originally Posted by Jfriah View Post
23.976 and 29.97 should play well together.

Keep in mind, especially for music, "seconds are seconds" and it is just a different number of frames in those seconds.

You're working in Pro Tools--

Create a new session in 29.97ndf. (to make it easier, make the session start the same as your picture file start, ie: 00:58:00:00 or whatever it is) Go to the 01:00:00:00 mark. Highlight a frame and use signal generator to create a 1 frame blip. Then pull your reference movie in, which is 23.976. Notice anything?

Now switch your session to 23.976. Your blip file didn't move, the timecodes just changed their display times.

The composer is giving you files-only, correct? You're not chasing a tape machine to play back cues?

And the composer will tell you if he/she attends final mix and sees anything that doesn't seem to line up.

Jeff
Thanks, Jfriah.

Unfortunately, I have Pro Tools LE without any add-on tool-kits, so I lack time-code/frames in the transport and timeline.

To elaborate, I think the confusion came in that the composer told me his Digital Performer (an older version) would only support 29.97 FPS and 25 FPS sessions. I wasn't sure what this meant with regards to the 23.976 FPS movie he was given and how he would be working from it. I worried that he may convert it to 29.97 before working on it, or that Digital Performer may change the frame-rate of the movie itself on import (I've never used DP so I don't know how it goes about it's video import, whether it just opens the video or actually copies and processes it to match the session settings).

I reasoned that if the composer was working from a different frame-rate, that his cues would be out of sync with mine by the fact that he is seeing a different number of video frames per second than I am. I was afraid that beyond cues not syncing, his compositions would be at a different tempo as well (slightly faster). Is that what would happen if say, perhaps by mistake we had received exports at differing frame rates from the picture editor?

To my surprise, when I received the tracks from him everything lined up and worked without a hitch, tempo and all. I was curious as to why this was… or maybe I'm missing something fundamental here…

When a DAW does not support a specific frame-rate, what does that mean exactly? Is that with respect to playback of the videos it loads or just by the functionality of the transport/time-line and time-code readouts?
Old 17th May 2010
  #49
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I'm afraid that 'depends' on the DAW/software.

I know LE and non- DV toolkit Pro Tools systems have limitations with respect to time code and grid/frames but as I've never used them for post, I can't speak to that.

Nor can I speak on DP.

Sorry!

But I can tell you that if your composer worked in 29.97 to the same picture you are, you can continue to work in 23.98 and import his tracks and they'll time out fine, or switch to 29.97 for your final mix and your pro tools code / ref video code just won't match up.

But if you're in LE and don't have code reference anyway.......

-Jeff
Old 18th May 2010
  #50
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You are good as long as both of you have video that is exactly the same running time, as played in your rooms. You can name the seconds anything you want as long as both projects are the same length in real time. Head and tail pops are your friends.

Philip Perkins
Old 18th May 2010
  #51
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Quote:
Originally Posted by philper View Post
Head and tail pops are your friends.
Amazing how many people forget those... especially on shows with any fades / black slugs within.

...had a production swear up and down the wall at me once when doing final laybacks that the show was out of sync. My answer was "you were here for the final mix! Did it look out of sync?"
"No..."
"Then it must be on your end..."

Turns out the video system randomly was throwing black frames in, and it just happened to be in commercial breaks twice.

"If you'd given a tail pop, that would have been quite evident"
"Oh."

Jeff
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