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Telecine 24fps film to 29.97 to 24fps synch problem
Hello all I cam working on a feature film and have encountered a synch problem.
My film was shot on, well, film, 35 mm, 24 fps, double perf.
I received DV tapes back from Technicolor, at 29.97. From there I do the following:
1) Go to import: import cinema tools telecine list.
2) Select the ALE file from the batch that Technicolor sends over. From there it asks if I want to either use or create a cinema tools data base. I just called mine reels and have used it every time since.
3) A batch list then imports into my bin window.
4) In Audio\video settings I have set my device control to LTC for time source, and made sure that the default time-line has been set to non-drop (as this is the info I was given from Technicolor in terms of their out-put settings.)
5) I go to log and capture, select off-line files to capture. It seems to create it own capture settings from the ALE file, as well as contain the reel info. My footage comes in at 29.97.
6) After the files have been captured, I go to Cinema tools. I select reverse batch telecine. I select 24 fps (as per Technicolor), and keep originals.
7) Import the reversed files back into FCP.Now it seems, however, that with shots longer then 3 minutes, my sound is beginning to get ahead of my audio. In my five minute takes it about 3 frames.
Please note that there is 24 fps timecode burned into the dallies, and that they have maintained time code synch when placed on a 24 fps time. I have also done tests though cinema tools at 23.98 fps on a 23.98 timeline, but it likewise maintained timecode but not sound synch. Originally, I also attempted to capture at 23.98, and 24 directly from the tape but the time-code synch and thus our on-line was lost.
Has anyone else ever encountered this problem or have any suggestion as to how to fix it?
Thanks
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4 Replies
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Hi Alex,
How are you ingesting sound? Are you syncing digital files after you run the video through cinema tools? Or is the audio already married to picture on your rushes tapes?
I would also recommend that you work in 23.98, NOT 24.00 (which is what you are using, if I understand your post correctly). 23.98 (or, more correctly, 23.976) is the standard way of working and will cause much less headaches down the road then 24.00.
Matt Lyon
Editor
Toronto -
Hey Matt,
Yes, I am working in 24 FPS as per Technicolor’s orders. I’ve also done tests at 23.98FPS, but that too goes out of synch. My sound is digital files recorded on set, that I then synch to the picture suing the clapper and though I am not sure what device the sound crew is using they have it set to 24 FPS. Any other suggestions as to what could be wrong?
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It sounds like it could be an issue with the way the sound files were imported into Final Cut Pro. I’ve had this situation in the past, which may or may not be your issue:
Certain types of media (stills, sound files, etc) that are dragged and dropped into the bin will “inherit” different properties depending on what the default timeline setting happens to be. It could be that you might have had a 29.97 drop frame timeline selected in your Audio video presets, so when the audio files were imported, they were given certain properties. If you then try to put them in a 24.00 fps timeline, FCP might now think that it needs to apply some kind of pulldown to the media … which is actually causing the files to drift out of sync.When you look at the clips you’ve placed in the timeline, do you see a yellow or orange bar running across the top of the audio media? This is an immediate clue that FCP is doing something funny with the audio.
Does any of this sound like it might apply to you? Let me know and I could walk you through fixing it.
Matt Lyon
Editor
Toronto -
Sorry Alex, I’m re-reading the thread and realizing I’m probably just overthinking this problem. This is sounds like it is really just an issue of needing to apply pulldown to your audio files. Telecines don’t run at 24.00 fps when they do a standard definition transfer to NTSC, they run at 23.976 — in effect slightly changing the speed of your picture. Simply running the sound recorder at the “correct” TC rate in the field does not compensate for this (and let me just add that my memory is a little hazy at the moment since it’s been a few years since I’ve dealt with this).
If the lab syncs your rushes, they will compensate for this automatically. Since you are doing it yourself, you’ll need to speed adjust the audio files by 0.001 (or 23.976 divided by 24.00). Off the top of my head, I can’t honestly recall whether you need to speed up or slow down the audio (I guess it depends which way it is drifting!)
FCP won’t do this speed change properly, you’ll need to use a decent digital audio editing program.
A bit of googling for “audio pulldown” and similar terms should yield lots of info. Or give Technicolor a call and hopefully they’ll help you out.
Hope this helps!
-MattMatt Lyon
Editor
Toronto
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