Pull up conversion to resolve sync issue

Question

Level 1

8 points

Pull up conversion to resolve sync issue

Hi

I have a sync problem on a feature film I am working on. It's a musical. I recorded the songs before the shoot in Logic Pro and produced BWF rough mixes at 48k/16 bit. During the film edit there seems to have been a pull down conversion because the film audio now drifts ahead of my original multi-tracks. A colleague has tested the required pull up in Pro Tools (it's NTSC to Film) and this put the audio perfectly back in sync. I don't have PT.

Is it possible to load the multis into STP and do a pull up conversion and then drop them back into Logic? I am new to STP. From what I've read you can pull up/down within a project but it doesn't export the pull up/down. I don't know how but I believe i could do a time stretch - I'm not keen on this as I understand it will introduce audio artefacts. And from what I've read there's no preset for timestretch so I'd have to do key in the % for every file (one song has over 80 tracks of audio!)

(just in case you're wondering.... for complicated underscoring reasons I need to sycn the multis rather than mix the tracks out of sync and do the pull up of the mixes at the end)

Cheers

Logic Pro, Mac OS X (10.7.5), Composer, sound designer, performer

Posted on Mar 26, 2013 3:28 PM

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Answer 1

Studio X

Level 7

27,229 points

Mar 29, 2013 3:22 PM in response to PF Bungie

Perhaps if you described the issue more directly we could help.

What format is the video? codec, framerate?

What format is the audio?

What program are you working in?

What are the sequence settings?

x

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Answer 2

PF Bungie Author

Level 1

8 points

Mar 30, 2013 9:09 PM in response to Studio X

Video is is 24 fps H.264. It's locked off - they're grading it now so there will be no tinkering with time in that realm.

Audio that went into FCP (rough mixes)was 48 k, 16 bit BWF. The Logic session was set to 24 fps before these mixes were bounced out. The Logic session itself is 24 bit. These original mixes when dragged back into the session they originate from are in perfect sync. When the same mixes are dragged into the OMF derived from the movie my mixes are slower than the film. The OMF audio and the audio embedded in the QT are in sync. So I am slower than the film.

As I mentioned I am working in Logic Pro- The film was edited in FCP.

I don't know the sequence settings in FCP but my editor says she was aware of the quirk where the sequence settings and default settings might be different such that the audio might be pulled up or pulled down. (Despite her protestations I'm pretty sure that's what happened - but she is very experienced). I actually know nothing about FCP except what I've read on the web.

My editor might suspect I am the culprit. She claims that the mixes I originally gave her are 'at 30 fps.' Maybe someone out there can clarify something for me. My understanding is that BWF are time stamped but not with a frame rate. ie; the embedded TC is just a time (as in hours:minutes:seconds:milliseconds)? Even my BWF had an embedded TC of 30 fps we have established that the correct amount of pull up to put my out-of-time audio in sync with the movie is .1%. That's NTSC to film - not the 4% required to correct a 24 to 30 fps discrepancy.

My original question stands btw. I'm a STP newbie too and I'm wondering if I can do pull ups in STP. If so how do I export this audio out of STP?

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Answer 3

Studio X

Level 7

27,229 points

Mar 31, 2013 1:11 PM in response to PF Bungie

It could simply be a NonDropFrame to DropFrame time code issue - ie the difference between the true 24 fps of film and the 23.98 of video running at "24p"

If this is the case, one of you is NDF and the other is DF. Descide who is in control and conform to that frame rate.

Cheers,

x

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Answer 4

PF Bungie Author

Level 1

8 points

Mar 31, 2013 4:55 PM in response to Studio X

Yes - that is the problem. I knew that when I first posted.My question is the same as in my last two posts:

Is it possible to load the multis into STP and do a pull up conversion and then drop them back into Logic? I am new to STP. From what I've read you can pull up/down within a project but it doesn't export the pull up/down.

Cheers

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