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FCP-help! Audio drifting - but all is in 48kHz

A

Askvb

Hi

I'm working on a feature now, and is currently on the audio-part in soundtrack pro after sending from final cut pro. But when I send it back to fcp (export in aiff and xml), the audio is drifting out of sync - just as if it where a different bitrate, although it's not! Everything is in 48kHz!

Have anyone else had this problem?

Info: converted the movie files from h.264 (DSLR (44.1kHz)) to prores 422 in mpeg streamclip, recorded audio separately in 48kHz and synced it using pluraleyes, every other files in stp (foley, adr, music, etc.) is also 48kHz. Using FCP 7.
 
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What are the audio settings for your sequence in FCP? Does it start drifting right away? Quickly or slowly? What framerate are you using in your sequence? 23.98p is different than 24p.
 
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1. Audio settings is 48kHz, 32-bit.
2 .No, it is completely in sync in the beginning, but slowly drifts away (video goes faster than audio), and after about ten minutes, it's 4 seconds out of sync. EDIT: 1 second, not 4.
3. 25p
4. Yes, but 25 is 25, right? It's only 24 and 30 that's not "24" and "30"?
 
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And I think I just found the problem: I opened up the XML-file from Soundtrack pro in Dashcode, and there some of the audiofiles was tagged with "timebase=24" and "ntsc=true". Hence I suppose I need to convert them in stp to 25p - but since it's audio it's not coded in frames anyway. Solutions?
I think I'll try to manually tags the files with 25p and "ntsc=false" and see what happends, but needs to find a stable solution.
 
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Yes, it seems so, but can't find a way around it using master mix-export in stp. But now I tried to export it with individual tracks, and then everything was correct back in fcp - no drift! Must be some kind of bug in stp when having different frame rates on audio (but same bit rate) and using master export.

I'll just use the individual tracks option for this project, and pay even closer attention to the different files next time :/

Thanks for all help!
 
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Askvb said:
Must be some kind of bug in stp when having different frame rates on audio (but same bit rate) and using master export.
Click to expand...

This was a well known FCP bug. FCP seemed to select the "slowest" audio sample rate and base the exported audio upon that. So even though you did everything perfectly importing the production sound (16bit/48kHz), when you imported a sound effect or song from an audio CD (16bit/44.1kHz) the "slower" sample rate (kHz) became the default export sample rate FCP. It used to drive folks really crazy when they would import low sample rate MPEGs, which can have sample rates as low as 16kHz.

This exact problem used to drive me nuts when importing OMF files into Pro Tools. They eventually did fix the OMF export sample/frame rate issue.
 
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