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QT .mov file conversion

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Ricky Barrow
QT .mov file conversion
on Aug 22, 2012 at 7:55:08 pm

Desperation leads me here as, hopefully, a forum to find a solution. I have a QT .mov file, ProRes 422 (HQ), created in realtime from capturing to tape through FCP. The file, which should be like the tape at 720p 59.94 comes to me and Movie Inspector shows 59.84 fps - thus when trying to import or transcode into Avid MC, I get a sync issue, video lags audio. I suspect corrupt data(metadata) - how can I correct this - in ANY WAY? Cinema Tools does not allow conform to 59.94 - I tried this method on another file and made the mistake of creating 29.97fps, thus in Avid it was slo-mo .... I played the file twice speed, realtime and captured the AV into another Avid to finally get a file in sync at normal speed with which to edit - I do not want to go through all that again ... surely there is a way to fix this differently? As a second question, the engineer in me, how can I solve the root of the problem? Is the system on which the file is created just not powerful enough to handle ProRes 422 (HQ)? I have received files from him in ProRes 422 (LT) which did not pose this issue.

Thank you for any and all help!

Ricky

Ricky


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Craig Seeman
Re: QT .mov file conversion
on Aug 26, 2012 at 8:52:02 pm

I'm often dealing with odd frame rates as is typical when recording live streams (as in live streaming to the internet). You can take the ProRes file and encode again to ProRes to the proper frame rate in Compressor.

I can't speak to your specific specs but when I do live encoding to ProRes using Wirecast for example, the encoder will adjust the frame rate rather than drop frames if there's any reason why it can't maintain the frame rate. The result is that you have a file that plays just fine in Quicktime for example but will drift out of sync in many NLEs (FCPX seems to be an exception). This is because, unlike Quicktime, the NLE is forcing the file to a standard frame rate, thus resulting in the audio drifting out of sync.

There are a variety of reasons why and encoder might not be able to maintain frame rate. One thing to avoid is using the System drive because it's also running the OS and applications. Other important things are the sustained throughput of the connection to the drive and the drive speed itself.


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Ricky Barrow
Re: QT .mov file conversion
on Aug 27, 2012 at 1:13:50 pm

Thank you! This is extremely valuable information for me and explains a LOT. It is all making sense to me now - thank you again, very much!

Ricky


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