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WHy does my sound always go out of sync?
Hello,
I have an Apple Mac Pro 2X2.8Ghz QuadCore Intel with 16GB RAM. I store all my media on a Disc Array that is connected to my Mac Via Fibre Channel.
I am working with a Quicktime that is Motion JPEG A 854X480, it is 6.42 GB and has a data rate of 13.73 mbits/s, when I test the read/write speeds of my Disc array I am getting way over 300mbits/s.
Please can someone tell me why, when I play this back in Final Cut Pro, it drifts hugely out of sync. If I play around a small area it will be in sync just fine but if I play back the whole sequence it drifts, if I output a quicktime of the sequence the sync on the quicktime is fine.
I broke the hour long quicktime into 1 minute sequences and still have the same problem.
The original quicktime is 24fps and my sequence is set to 24fps. All the settings in my time line match the original sequence.
Please help!
Thanks
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7 Replies
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[Sebastian Swallow] “Quicktime that is Motion JPEG A 854X480,”
[Sebastian Swallow] “Please can someone tell me why, when I play this back in Final Cut Pro, it drifts hugely out of sync. If I play around a small area it will be in sync just fine but if I play back the whole sequence it drifts, if I output a quicktime of the sequence the sync on the quicktime is fine.”
OK
you have 2 problems in your first comment here- both exacerbate the overall problem.FCP does not handle or consider any of the Motion Jpegs as real time codecs, there for the CPU is handling the video decode separately than it is handling the audio.
Secondly – that is not a standard video frame size- FCP is not happy when playing content that is not part of the SMPTE specs for video delivery. Why the weird frame size?Basically all of the CPU processing is going to try to handle the video playback- there for your audio-which I am going to guess is not a 48K aiff audio- has less of the CPU available to handle the audio decode, there by letting it slip out of sync since – audio is not as important as video is to FCP’s processing engine ( not that I agree, I know that FCP handles video before audio even when there are embedded in the same file.
gary adcock
Studio37
HD & Film Consultation
Post and Production WorkflowsInside look at the IoHD
https://library.creativecow.net/articles/adcock_gary/AJAIOHD.php -
Um, the so-called weird frame size is standard DV anamorphic, in an unstretched format. Another iteration of this which Compressor will export is 720×404 or something to that effect. Not weird at all.
Have a wonderful day.
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[Chris Poisson] “Um, the so-called weird frame size is standard DV anamorphic, in an unstretched format.”
Ah
but that is not a SMPTE spec Chris,Since SMPTE does not support Baseband video at that size, that is part of the issue,
because you can do it does not make it legal video for anything else.gary adcock
Studio37
HD & Film Consultation
Post and Production WorkflowsInside look at the IoHD
https://library.creativecow.net/articles/adcock_gary/AJAIOHD.php -
It seems like I have read somewhere that 854X480 is the PAL standard for Anamorphic DV and 720×404 is the NTSC standard for Anamorphic video.
Just my two cents…
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Wayne Carey
Schazam Productions
https://web.mac.com/schazamproductions
schazamproductions@mac.com -
Yes, that makes sense Gary.
Have a wonderful day.
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PAL square 16:9 is 1024×768, NTSC D1 864×486, NTSC DV 854×480 (actually for all it’s around 8 pixel more in width, but it is a bit complicated to explain why)
Anyway: DV NTSC anamorphic is 720×480, DV PAL anamorphic is 720×576.
To get an 16:9 image the ‘Anamorphic’ flag in FCP has to be set manually in most cases when you import a file.
This has to be done even if the movie shows up correctly in QT Player.Andreas
Spherico
https://www.spherico.com/filmtools -
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