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Audio (AIFFs) goes out of sync when transferred to another hard drive
Hi everybody,
We’ve been having a very strange problem on the production we are working on.
We have audio (recorded separately from video) in AIFF format. After working with this audio – syncing up and editing etc on one external hard drive, we have copied all the media, including this audio, to a new drive to work with it on another machine.
When relinking, Final Cut says that the start and end times have changed, despite the fact that it is an exact copy of the original media. If we continue and relink, the sound is a few frames out of sync.
FYI – the audio has been converted using compressor.
Has anyone experienced anything similar?
Thanks,
T
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9 Replies
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The audio files get time base stamped according to the A/V settings the machine is set to. The global settings…the Easy Setup….NOT the sequence settings, which probably do match. This is because FCP can have sequences of different timebases within a project. Make sure the settings on Machine 2 match those of Machine 1….quit FCP, restart, then attempt a new reconnect.
Hope that helps
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48khz, 24-bit
The sound was slowed down in Compressor to 100.15% of the source duration in order to match our video.
(another story: Video was recorded on a Canon 5D, for some reason the video and audio did not match and sync would drift over time).
T
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THAT’s an interesting one.
I wonder… It might take a bit of detective work then! I did actually have an issue with some sequences that had defaulted to the wrong time-base (23.98 I think). This might explain it. Maybe the easy setup on that machine was wrong to start with!
I’ve been working on Avid recently, so avoiding this little minefield of different editing timebases etc within the same project.
So the audio files get time-base stamped when you bring them into the project… Is there any way to change that?
How would you recommend dealing with the problem of some footage that’s gone out of sync as a result of this happening? Is there another way to relink those files?
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Actually, I’m not sure this can be the issue.
I did a test – all on one machine, one copy of Final Cut and within one project – where I took the media residing on external drive A, copied it to external drive B, then hid the original media (drive A) from Final Cut by putting it in the Trash. I then relinked the now offline sound files to the new copy on drive B, and got the same problem: start and end times different, and when relinked the sound was out of sync with the video.
Odd, no?
T
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Tom,
You might want to give my tutorial a read, it might shed some more light on your issue.
https://library.creativecow.net/lyon_matt/fixing-fcp-assets/1
FCP has a LOOOONNGGGG memory for badly imported audio, so you need to follow a very precise set of steps (which I discuss in my article), in order to get the files imported correctly.
Hope this helps,
Matt Lyon
Editor
Toronto -
Very good!
Thanks Matt. This is useful information.
I’m still not sure why the problem would happen even when making an identical copy of the same media to a new drive, same machine, same FCP, same project, but I will read through and hopefully find some answers!
T
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It’s a really awful problem.
I can’t see why Final Cut wouldn’t import audio with some kind of universal time-stamp.
There is also nothing to suggest that this process even happens on import. It’s completely invisible.
Thanks for the help everybody, I think I know how to go about fixing this now.
T
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I think it happens because FCP treats every re-link operation like a fresh import (where it uses the default sequence setting to derive its timebase). This /might/ not happen if you had a mirrored folder structure on each system, so no re-linking would happen upon opening your project.
I think this behavior goes back to early versions of FCP, when film workflows were more common. It is trying to automagically compensate for telecine pullup/pulldown (back in the days when nothing shot natively at 23.976). IIRC, there is mention of this “feature” in old versions of the manual.
Sadly, it is clearly causing more harm then good these days. This behavior should have been yanked from the code eons ago, imho. And I agree with you that there should at least be some kind of warning during import, or some kind of user-selectable option in the preferences to disable.
Matt Lyon
Editor
Toronto -
The original 5D firmware recorded video at 30fps and 24 fps instead of the more traditional 29.97 and 23.976, which would cause sync issues with external audio. Another way, rather than altering your audio, would have been to conform the video clips in Cinema Tools to 29.97 or 23.98 .
The reason why FCP time stamps is because there are instances where the audio needs to be adjusted.
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