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Sound sync issues and frame rate conversion
I am working on a documentary that we are about to uprez from SD to HD. It was shot on two DVX100’s in 24pa and edited in a 24 fps timeline. It was taken to a Lab in Atlanta for Color correction and sound mixing, and they printed the movie to two Betacam SP tapes and one Digibeta tape. They converted the frame rate to 29.97 fps for the print.
We’ve reimported the betacam footage because the Lab gave us no digital files of their CC or sound work. Therefore our CC and mizing labor rests only on those tapes. Obviously, reimporting the CC’d footage is essentially useless due to the large amount of noise from the import process, noise that becomes especially visible when uprezzed. However, my director really likes the sound mix from the tapes, so we’d like to use the sound tracks with our original digital footage. The uprezzed HD files needs to be 1080 23.98 pFs. Therefore, the 29.97 fps sound file needs to be converted to 23.98. However, my director also wants to put some of the sound files from the original mix, the 24p stuff, in with the 29.97 footage. If none of this makes sense to follow, it comes down to this: We have 23.98 footage with an audio mix of both 23.98 audio mixed with 29.97 audio in a 23.98 fps sequence in FCP six.
In a 29.97 fps timeline with the 23.98 audio mixed with the 29.97 audio, the mix sounds fine. Either there are no sync issues, or any drift is not noticeable due to the short length of the 23.98 fps audio clips.
Problems:
In the 23.98 timeline, the framerate we ultimately need to go to, there is noticeable drift by the end of the timeline (a 94 minute feature). The 29.97 audio spans the entire movie, with the 23.98 stuff “sprinkled” in. Clearly the conversion is causing problems.What options do I have to fix these sync issues? I’m open to anything.
Thanks so much for thinking about this incredibly unattractive issue, and I am extremely grateful for any and all assistance.
JC
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3 Replies
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I’m having a very similar problem. Did you ever figure this out?…
Thanks. -
I had a strange problem when working on a 22.5 min television program. The sound mix when imported was being given an assumed frame rate of 29.97 within a PAL 25 sequence. Which took a while to figure out until I opened it in soundtrack. I have to admit soundtrack is a bit of a mystery to me but what I was able to do in soundtrack that I couldn’t do elsewhere was adjust the framerate of the audio track. By going to the project settings and saving the project with a new frame rate I could fix it. And voi la! Anoying, Yes! But the day was saved and we made our deadline so all was well.
Hope this helps! -
It does. Thanks!
-Justin
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