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Audio sync problem in FCP (Sub-frame editing required) one frame accuracy just not good enough!

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Dion Johnson
Audio sync problem in FCP (Sub-frame editing required) one frame accuracy just not good enough!
on Jan 26, 2012 at 1:04:19 am

I'm hoping an FCP genius out there can help me with a sync issue that is driving me insane!
I've worked in broadcast TV for over 20 years but filmed a concert (last minute) with two DSLR's.
The main camera (close-ups) were shot at 1080p (24fps) and the other camera (wide) at 720p (29.97fps).
I have been given the master audio files [44.1khz rate] (from desk) which sound amazing, and I've set up timeline sequence at 720p with 44.1 and 24fps. Why is it that on each individual song, there has been a slip (cumulative) so that it starts off in sync and then ends up half a frame out by the end of the song, (say around 4 minutes). I've just been given a new version of the full concert as one whole file, so I'm going to start from scratch. With the violinist and guitarist playing quite fast in places, one frame accuracy is simply not good enough. Can anyone shed light on this mystery and offer a better workflow solution? It took me around two weeks to cut the first version, so I'm assuming it will take that again to re-cut the new version. Why is it that FCP7 cannot perform sub-frame editing of the audio on the timeline??? You can only do it in the preview window and then the scrub-bar is not accurate (it's too fat in width!!!) enough to perform the task by sight on the waveforms!!! Arrrrghhhh!!! Does anybody have any thoughts on this issue?
Does Avid allow for more accurate sub-frame editing?
When a band plays at over 100bpm, one frame accuracy simply is not good enough.


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Shane Ross
Re: Audio sync problem in FCP (Sub-frame editing required) one frame accuracy just not good enough!
on Jan 26, 2012 at 1:39:38 am

[Dion Johnson] " Why is it that FCP7 cannot perform sub-frame editing of the audio on the timeline???"

It can...

http://proappstuff.com/proapptipsvideotutorials/879F6B61-CFF9-4FD1-8D43-FDF...

[Dion Johnson] "Does anybody have any thoughts on this issue?"

Convert the audio to 48khz. FCP doesn't like 44.1. Not if you want to keep sync.

[Dion Johnson] "Does Avid allow for more accurate sub-frame editing?"

Avid doesn't allow for ANY sub-frame audio editing. ProTools does...

Shane
Little Frog Post
Read my blog, Little Frog in High Def


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Michael Gissing
Re: Audio sync problem in FCP (Sub-frame editing required) one frame accuracy just not good enough!
on Jan 26, 2012 at 2:29:02 am

Your DSLR footage is 23.98 not 24 so your sequence should match that. Make sure your Easy Setup is set to 23.98, 48khz before you import the 48khz version of the music file and it should sync.


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Dion Johnson
Re: Audio sync problem in FCP (Sub-frame editing required) one frame accuracy just not good enough!
on Jan 26, 2012 at 2:50:03 am

Thanks for the responses. Much appreciated. The audio file is a WAV file mastered at 44.1 not 48. Is this going to cause problems with a slight speed change? The band are professionals and I think they would notice this if I did. So should I convert the 44.1 wav to 48 in QuickTime first, then import it into the FCP timeline set at 48? Also should I convert my footage from both cameras (one being 24 fps or like you say 23.98) and the one which is 29.97fps, should that be pulled down to 23.97 dropping frames? I'm new to this sort of workflow.
I've already converted the native 1080p 24 fps files to ProRes HQ, so should I do this again with a new setting? Sorry for all the questions, but I've just spent 2 weeks cutting this full concert and it has sub-frame audio problems with sync everywhere. I want to get it sync perfect for the band, which means at least another week in the edit suite.
What is the best workflow for this?


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Michael Gissing
Re: Audio sync problem in FCP (Sub-frame editing required) one frame accuracy just not good enough!
on Jan 26, 2012 at 2:59:10 am

Can't help with the correct way to convert 29.97 to 23.98 as I work in the 25 world (thankfully).

Quicktime Pro or Compressor can do the sample rate conversion from 44.1 to 48. It won't change the sound but FCP really only works reliably at 48khz and sequence and file settings must match as it doesn't handle on the fly sample rate correction at all well.

Shane's tutorial gives the best workflow for DSLR to ProRes -

http://library.creativecow.net/articles/ross_shane/tapeless-workflow_fcp-7/...


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Geoff Norman
Re: Audio sync problem in FCP (Sub-frame editing required) one frame accuracy just not good enough!
on Jun 30, 2012 at 9:44:50 pm

Ignore the B#(*@ing about linguistics in the post but there are even good images that describe how to Subframe Editing AND Subframe Scrubbing in FCP 7

http://forums.creativecow.net/thread/335/33539

Side note. In FCP X you can do subframe editing and scrubbing...if you are willing to detach audio from your multiclips when editing concert footage :P I only bring it up because I am editing a music event as well and was mostly successful and letting FCPX sync AND create a multiclip with the Audio as a separate angle with no video attached (Don't know why this was so hard to do in FCP 7...) but now that the Audio is joined in the multiclip as an angle, I am hand synching a better mastered audio file to the ambient audio in the multiclip...and I can subframe scrub and edit the detached audio to my heart's content but the audio file in the multiclip offers no subframe scrubbing or editing beyond keyframes @_@ matching the stupid wave forms WITHOUT FCP 7's longed for viewer to enlarge the waveforms and GASP let you place subframe markers!! is making it nearly impossible to sync within less than a frame or two

Beware the fast or illconceived workarounds people offer you! @_@ @_@ Beware...


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