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Corrupted media from modifying timecode?
Hello,
I’m fairly new to FCP. I was editing two sequences each with two .mov video tracks, and trying to sync the timecode of the two source files in each using ‘Modify Timecode’ by going in and changing the first frame to 00:00:00:00 in each clip. At some point during this process, one of the two files in each sequence became corrupted in a way that suggests they were partially overwritten: ie. they shrunk to about 1/40th of the size, can’t be opened in Quicktime, and, although they remain open in the timeline, only the first few seconds of them will play. Afterwards all that shows up is a black screen. This happened to one file in each of the sequences, and, according to the ‘last modified’ time in finder, about 30 minutes apart. One of the files had a backup and one didn’t. I’ve given up any hope of recovering the lost file, but I’d like to make sure this doesn’t happen again.
There were a couple general error messages that popped up whose numbers I can’t remember: I ignored them since they didn’t seem to be affecting what I was doing. I have a few questions, since I’m not sure what exactly caused the error:
1) Can changing timecode as I did have this kind of effect on files? I could see a corrupted timecode occurring, but I was pretty shocked that the file seemed to be partially overwritten.
2) Is this some unrelated bug in FCP? Has anyone experienced anything like this before?
3) Could this be completely unrelated? The files I was working with were on a hard drive accessed through a network. Could this have something to do with it? The rest of the files on the drive seem to be fine.
I was using FCP 7.0.2 on a iMac running OS X 10.5.8.
I’m sure there are some details I’m forgetting.
Thanks.
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10 Replies
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I can’t imagine how changing TC could make the file corrupt.
TC in QT is just an extra TC track. (that you can remove using QT pro).I can imagine that linking to a slighly modified timecode will throw the edit timing off. That is the nature of the beast, and as it should be.
Something else is fishy.
Bouke
https://www.videotoolshed.com/
smart tools for video pros -
Ya know? I rarely feel the need to change it. Even with multiclips or other. I’d think if you need timing though it would help to go to have a reference. But I think AUX timecode is best to use for this.
Jerry
Apple Certified Trainer, Producer, Writer, Director Editor, Gun for Hire and other things. I ski. My Blog: https://blogs.creativecow.net/Jerry-Hofmann
8-Core 3.0 Intel Mac Pro, Dual 2 gig G5, AJA Kona SD, AJA Kona 2, Huge Systems Array UL3D, AJA Io HD, 17″ MBP, Matrox MXO2 with MAX Cinema Displays
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I also like aux tc, as i never ever want to mess up my original tc…
However, setting AUX TC is almost exatcly the same as altering normal TC.
A new TC track is added to the original QT file on disk….Bouke
https://www.videotoolshed.com/
smart tools for video pros -
Bouke, I know it’s not likely to fix the problem, but can any of your tools remove his timecode track without opening the file?
He says it won’t open in QuickTime Player. It’s a weird problem, and I don’t think it would hurt to try. -
QTchange is capable of removing the TC track, but not without opening it.
however, it does not need to decode anything, so perhaps it will work…But again, i doubt it’s the TC track.
There seems to be bitrot on files occuring all over the world.
Neil S. had troubles with corrupted files, i myself recently had very weird stuff going on with files written on PC using MacDrive, that weren’t able to read correctly on Mac, but fine on PC…I guess it’s the weather.
Bouke
https://www.videotoolshed.com/
smart tools for video pros -
Huh. Well if it’s not the timecode, I have no idea what’s going on. I doubt removing the timecode would change things since the file is significantly smaller. It’s like it was partially overwritten by itself but stopped almost immediately after it started.
Is there any way to view some kind of log that might help shed light on this? I’ve been poking around in the console but haven’t really found anything useful.
Thanks for your responses!
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Oh, I don’t know if this is relevant at all, but the files I was working with were fairly large (~50GB).
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Alright, I recreated the error! Here’s exactly what I did. I had two clips sitting on top of each other. I selected one clip, went to ‘Modify timecode’, selected ‘First frame’, deselected Source TC, selected Aux TC 1, and changed the first frame to 00:00:00:00. No problems there. I then went to the other clip and did exactly the same thing. As soon as I hit ok, a general error popped up (no number), and voila! My 60 GB clip has shrunk to 1.78 GB.
Am I doing something terribly wrong here? Or is something just messed up?
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This is seriously scary!
Start making backups…What are you drives like?
(no answer, just curious as i’ve seen other corruption lately…)Again, be afraid, be very, very afraid. Something is really wrong.
(and i can’t help as i’m in the dark as much as you are)But, look at the bright side. You can always contact Apple’s tech support and they will fix it tonite!
Bouke
https://www.videotoolshed.com/
smart tools for video pros -
I’ve seen the exact same issue which I briefly corresponded with Bouke about. I modified TC of a QT movie that was a Canon 7D shot file. The file was on an external drive formatted NTFS.
Changed the TC and the file went bust. Same symptoms as yours. Size shrunk, no longer opens in QT.
I accessed a backup of the file, copied to my Mac internal, and TC change went off OK.
I think modifying the time code of a QT movie when the file is not on a local and Mac formatted drive makes the file go corrupt. I need to do this test on networked and FAT32 formatted drives just to check of that is the issue.
In the past I’ve seen issues when one sets a networked drive as a capture scratch. When one captures, the files come out without TC, or are corrupt.
I seem to remember reading up about how on a network information travels as packets. So when you open or write a QT movie you open the data out of sequence and if the TC data doesn’t come in in the right sequence with picture data, the file structure gets altered enough to lose some data and all timecode.
Just a conjecture. More info needed.
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Neil Sadwelkar
neilsadwelkar.blogspot.com
twitter: fcpguru
FCP Editor, Edit systems consultant
Mumbai India
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