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Rendering shifts video, creating loss of sync.
I came upon a few similar issues in this forum and elsewhere on the net, but none that found a solution.
I’m working with 720p 23.98 footage in FCP 6.0.2, shot on a Varicam, and all is well until I render a clip. Whether the render is necessary due to an opacity change or a filter applied, as soon as a clip is rendered, it shifts and becomes out of sync with the audio. If I undo the render, it plays fine again. It’s for a music video, so there’s only one long audio clip which stays put. When I watch the cut using the Safe RT preview before rendering, everything matches up, but as I said, if I place the playhead anywhere on the clip and render, when the render finishes the video actually shifts in the Canvas. I should note that my render settings under the Sequence menu are all correct.
The footage was captured at 59.94 in order to run it through the DVCPRO HD Frame Rate Converter for slow motion purposes, and that process worked fine.
What I’ve tried so far (with no success):
1. Trashed all of my render files
2. Trashed my FCP prefs
3. Repaired permissions
4. Copied the clips into a new sequence in an entirely new project
5. Nested the 720p sequence into a 1080p sequence (a shot in the dark to see if forcing all the clips to be rendered would trick it into working)
6. Forcing the render by exporting a full-res Quicktime
7. Exporting using Compressor
8. Sending render files to a different hard drive
9. Testing the project on a machine with FCP 5.0.4 (I found the following post where it had worked for someone with a related problem: https://forums.creativecow.net/thread/8/962498#962498 )
10. Placing the clips in a 59.94 timeline and rendering (ridiculously grasping at straws, I know)
11. And of course, restarting after many of the above attempts.
Currently I’m running the original footage through Cinema Tools to convert it to 23.98 to see if that changes anything (instead of using the Frame Rate Converter), but I’m not very optimistic since the FRC has never given me any trouble before.
My profile specs aren’t up to date. The current details are:
– FCP 6.0.2
– OSX 10.4.11
– Quad Core 2.5 GHz PowerPc G5
– 6.5 GB RAM
– Project file is on System Drive
– Render files are going to either a separate internal SATA drive (plenty of space free) or an external FW drive (tried both)Any thoughts would be very, very welcome.
Thanks!
Joni -
21 Replies
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I am confused. You said that you captured @ 59.94, but your timeline is 23.98? Then you ran it through the FRC to get 23.98 in a 59.94 timeline?
Please explain.
Jeremy
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Sorry, I should have been more clear. The footage was shot at 60 in order to be used as slow motion in a 24 sequence.
So we captured it at 59.94 because it’s necessary in order to run it through the FRC, and converted it to 23.98 for use in a 23.98 timeline.
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And the rest of the footage is 23.98?
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You betcha. I’m not mixing any formats, and everything on the timeline is 23.98.
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And the only audio is the music track?
What format is that?
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It’s an AIFF, 48 KHz, which is what the sequence is set to.
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Sorry for all the questions, Joni.
How’d you capture, firewire?
What happens if you render one clip at at time instead of the whole timeline?
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No apologies necessary, thanks for all your questions so far.
I captured via SDI through a Kona 3. However I’ve used this exact workflow a hundred times before and have never encountered this problem.
Rendering one clip at a time doesn’t help.
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Yeah, it’s suspicious to me.
[Joni Church] “Rendering one clip at a time doesn’t help. “
Does just that one clip go out of sync or then the whole timeline?
Are you working in DVCPro HD and is your Kona output set to 1280 8-bit? Try resetting your easy setup.
What happens if you leave your sequence unrendered then export a Self-contained?
It seems like we are missing something easy here, but I am coming up blank.
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It’s true, it does seem like something easy is missing, which is why I wasn’t worried about it at first. Now I’m not so sure.
When I render one clip on its own, it goes out of sync alone, the rest of the un-rendered clips are fine.
I’m working in DVCPro HD, and I did try resetting my Easy Setup, which didn’t change anything.
Leaving the sequence un-rendered and exporting a QT doesn’t help, because the force-render FCP applies before the export makes the clips go out of sync in the resulting QT file.
The abnormality in all of this is that it’s only the clips that have a filter applied to them (any filter, doesn’t matter which one) or an opacity shift that go out of sync when rendered. It’s not like the whole timeline is out of sync, or the sync drifts. It’s not even related to the audio at all, actually, that’s just how I first noticed it. Even with no audio present, if I pull the opacity on a video-only clip down to 60% and render it, it shifts. It’s puzzling.
I figure if I can’t get to the bottom of this before I need to show my client the video, I’ll have to figure out how many frames each clip shifts, and knock each of them out of sync manually before rendering so they line up once they’re rendered… but I hate band-aids and prefer to find the source of the problem, (as I’m sure you do as well).
Thanks again for your input, it helps having another brain checking in on everything.
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