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SYNCING 24FPS VIDEO WITH .WAV FILES


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#1 NICK BRAMPTON

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Posted 07 September 2009 - 05:57 AM

I am trying to synchronize an Apple ProRes 422 (HQ), 1920 x 1080 24 fps video only file with the mono sound from a .WAV file.

I have timed the spike on the wave form from the WAV file in FCP 6 so that it matches the clapboard closing on the video file.

But 5 minutes into the clip (which is seamless - no edits), the sound and video are out of sync (the video is lagging).

Any suggestions?
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#2 Kent Kumpula

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Posted 07 September 2009 - 10:34 AM

Speed up the audio (make it shorter) and change the pitch, so it won´t sound funny.
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#3 NICK BRAMPTON

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Posted 08 September 2009 - 01:27 AM

Hi Kent,

Thanks for the suggestion, but I'd prefer not to fiddle with the sound, as it is fine as it is.

I am guessing that what is happening is that FCP is doing something to the video (such as adding an extra frame every certain interval), which is causing the sound and video to go out of step.

Anyone have any other suggestions ?
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#4 Kent Kumpula

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Posted 08 September 2009 - 01:30 AM

Make sure your sequence settings match your videoclip, then it shouldn´t be adding any frames.
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#5 David Rakoczy

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Posted 08 September 2009 - 07:49 AM

Thanks for the IM but I can not help you. Sorry.. I always have the post House Sync everything for me... For sync I shoot 24fps and the Audio runs at 30.

Good luck. I'll bet you are frustrated! :(
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#6 Adrian Sierkowski

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Posted 08 September 2009 - 07:50 AM

How did you record the sound?
You are loosing sync, I think, because the sound was recorded differently than it should be. For examply your audio recorder was set at 30fps as opposed to 24 or 23.978. You're either gonna have to find where you start loosing sync and resync it and/or change the audio rate as mentioned.
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#7 Kent Kumpula

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Posted 08 September 2009 - 07:55 AM

Chop the 5-minute clip to several short clips and re-synch each clip. Make the clips short enough so that the synch is not lost (how short depends on how fast you loose synch).
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#8 Tom Hepburn

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Posted 08 September 2009 - 09:17 AM

Hi Nick,

I've had this exact same problem on a 10 minute clip. This is what worked for me, but keep in mind my Quicktime movie (pro res as well) was transferred at 23.98 fps. You may want to check that info in FCP or QT player. If your your quicktime movie was transferred at exactly 24 fps, then this solution won't work.
Obviously, you'll want to have a backup of your audio file first. If you go into an audio editing program and change the speed or pitch to 99.9% and then re-import to your timeline and all will be fine. You may also be able to do it from within in FCP, but I've never done it that way.

good luck.
Tom
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#9 Dan Goulder

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Posted 08 September 2009 - 04:06 PM

When film is telecined to a video format, the speed of the film is slowed down by .1%. The above advice given by Tom should put you back in sync. For future reference, you need to either use an audio recorder that allows for "pull-down", or one that records at 48.048 Khz while time-stamping the file at 48Khz (such as Sound Devices), if you're going to do your own audio syncing. If you have the post house sync up your dailies, then you can record dialogue at straight 48Khz, and let them insert the pull down compensation.
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#10 John Sprung

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Posted 08 September 2009 - 05:12 PM

To test whether this is really a "point nine something" vs. "point zero zero" speed issue, do a test: Roll picture and sound, hit the sticks. Wait 42 seconds, hit the sticks again. If the second sticks come up exactly one frame out, you have the "point what?" problem.





-- J.S.
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#11 Max Smith

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Posted 08 September 2009 - 10:22 PM

I've had audio sync issues with FCP that have been down to the easy setup settings being out of sync with the project settings (PAL versus HD):

This resolved it for me:
http://support.apple.com/kb/TS1256

Worth double checking.
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#12 NICK BRAMPTON

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Posted 09 September 2009 - 05:57 AM

Thanks to everyone for all of their super helpful (and prompt) suggestions. Much appreciated

I tried the 99.9% fix and it worked perfectly.

As the sound was recorded on a Sound Devices 702 (D. Goulder must be clairvoyant !!), which lets me set a sample rate of 48.048k but which stamps the file as 48k, I will use this setting on my next recording and hopefully avoid having to fix the sound in post.

I will also drop a line to the folks at Sound Devices to suggest that they include a bit more detail about Sample Rates in their manual so that other neophytes don't experience the same problems.
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#13 NICK BRAMPTON

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Posted 09 September 2009 - 03:21 PM

After my post earlier today, I exchanged e-mails with the helpful folks at Sound Devices, who gave me a link to one of their articles on topic.

While it may be pretty basic stuff for you much more experienced types, if anyone less experienced is reading this post, the article may be helpful.

One can find it at: http://www.sounddevi...ormat-overview/
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#14 Dan Goulder

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Posted 09 September 2009 - 05:31 PM

(D. Goulder must be clairvoyant !!)

I knew you were going to post this.
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