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Unusual corrupt clips

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Bob Woodhead
Unusual corrupt clips
on Sep 30, 2014 at 3:01:42 pm

This has never happened to me, on any NLE.

I've got 3 clips, from same location, same camera, offloaded at the same time. No issues importing/transcoding into FCPX. From Canon MXF to ProRes.

During a project backup, all 3 failed to do a Finder level copy. In X, all 3 show up, with waveforms, as usual. I took 1 of the 3 clips and exported chunks (Master file), starting from the end of the clip, until found the section that failed. From that section, to the beginning of the clip, I could not export. Played from beginning, and until about 4 minutes into the clip, it played fine, then simply went to black. Took the filesystem a couple of minutes to "release", and then I could skip ahead in X and play the rest of the clip. At this point I'm going to assume the other 2 clips will exhibit similar issues.

Has anyone come across this kind of issue, and did you pin the cause on anything?

I've got to check the camera cards, but hopefully they haven't been erased yet. This has really shaken my confidence of "once imported, all is good". It's not unusual to import cards, then reformat & keep shooting. I've always dismissed the need to keep a copy of cards, as I've always thought of that as redundant to the imported ProRes (which will be backed up, along with the project, during normal ops).

"Constituo, ergo sum"

Bob Woodhead / Atlanta
CMX-Quantel-Avid-Premiere-FCPX-AFX-Crayola
"What a long strange trip it's been...."


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Bret Williams
Re: Unusual corrupt clips
on Sep 30, 2014 at 3:15:30 pm

[Bob Woodhead] "It's not unusual to import cards, then reformat & keep shooting. I've always dismissed the need to keep a copy of cards, as I've always thought of that as redundant to the imported ProRes (which will be backed up, along with the project, during normal ops)."

I would find that EXTREMELY unusual. Cards aren't that expensive. Some cost as much as a good BetaSP tape used to cost. The only reason we don't keep them as backups is they're so small. We could easily keep them and bill the client, but a USB 3 drive is cheap and more multi functional. Might as well reuse the cards. That said, we bring enough cards so that we don't have to reuse during a shoot. It's often the case that the camera op doesn't even delete them until he has to or at least for a couple of days just in case. On the shoot, we usually copy them to two USB drives at once or to the internal laptop drive and an external. Then, come back to the suite and copy them again to a raid 5. So at that point the camera op has files on the cards, they're on a couple hard drives/laptops and on a raid 5 which has it's own built in backup.


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Bret Williams
Re: Unusual corrupt clips
on Sep 30, 2014 at 3:17:21 pm

But sorry, I don't know about the clips. What about the original media, not the ProRes. Maybe the problem was the transcode.


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Bill Davis
Re: Unusual corrupt clips
on Sep 30, 2014 at 4:52:25 pm

I'm with Robin on this.

I know it's not "necessary" to work from sparse disk bundles or camera archives any more with the new Library system. But I still maintain the workflow from before where the first thing that happens with any field card is to either use Camera Archive if I'm working inside X - or Anereas Keils SCDI program if I'm in the field and not running X - to make card clones religiously.

I find having a digital clone that can be duped and archive in two places just too calming to ever consider giving the workflow up.

For those with large networked systems, I can see the lure of letting the NAS backup handle things. But card clones just make me feel so much safer.

YMMV>

Know someone who teaches video editing in elementary school, high school or college? Tell them to check out http://www.StartEditingNow.com - video editing curriculum complete with licensed practice content.


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Robin S. Kurz
Re: Unusual corrupt clips
on Oct 1, 2014 at 1:13:24 pm

[Bill Davis] "I know it's not "necessary" to work from sparse disk bundles or camera archives any more with the new Library system."

Not sure what sparse disk bundles (and why even use a bundle?) or camera archives have to do with the new library structure, since archives haven't actually changed in terms of use, format etc. But I also don't see the lure of using DMGs instead either. With my dedicated archive disk I have immediate and easy access to any and all files because they are in the FCP archive format. No mounting or anything needed, FCP sees all the contents as if they were just a folder. Also you can't put DMGs into your favourites bar for quick access and reimport (if needed).

I'm getting automatic triple-redundancy with this also. The original card archive, the imported material and the backup of the archive. All without any external apps or fiddling. But to each his own I guess. ;)

And btw I would ALSO archive the cards that shoot in ProRes (assuming FCP sees them in a way to allow for it) for the exact same reason: automatic triple redundancy. I personally never ever work off my only copy.

*******************

German language FCP X training: https://vimeo.com/ondemand/fcpxtraining


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Robin S. Kurz
Re: Unusual corrupt clips
on Sep 30, 2014 at 3:35:35 pm

[Bob Woodhead] "I've always dismissed the need to keep a copy of cards, as I've always thought of that as redundant to the imported ProRes "

I make ARCHIVES of every single card first thing and store them on an extra drive and import from them. There is no such thing as too much redundancy. Especially IF in fact your library goes south and you, like me, use the brilliant backups from FCP X itself, then you'd be potentially screwed without the archives (i.e. original media) to re-import from. It's by far the easiest, fastest and most of all smallest form of backing FCP X libraries up. Backing up transcoded media takes up exponentially more space and there's really no logical reason (for me) to include them, since I have the original files from which I can regenerate them again at any time if needed.

As far as the glitch is concerned: I would suspect the transcode may have a corrupt frame also. Though there's no way of knowing whether that happened during the transcode or if it in fact was already in the original file without the actual file to check. I might try re-exporting it (even to a different codec) to see what happens.

*******************

German language FCP X training: https://vimeo.com/ondemand/fcpxtraining


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Jeremy Garchow
Re: Unusual corrupt clips
on Sep 30, 2014 at 7:35:39 pm

[Bob Woodhead] "I've got to check the camera cards, but hopefully they haven't been erased yet. This has really shaken my confidence of "once imported, all is good". It's not unusual to import cards, then reformat & keep shooting. I've always dismissed the need to keep a copy of cards, as I've always thought of that as redundant to the imported ProRes (which will be backed up, along with the project, during normal ops).
"


I'm going to pile on here but, this is bad practice. I know it seems like it should be fine because it's "digital" but it was very rare that you would capture a tape, and then record over the tape to reuse. this is how you have to think of camera original media. You need to always be able to rely on it in case of failure.

I use Shotput Pro to make 2 and sometimes 3 copies of camera original material. One copy stays with the Library, and the other two copies are on other drives.

Once the job is over, I archive to two LTO tapes, and the camera original as well as any transcoded footage is archived along with the rest of the elements. The original media is still in the original structure. If FCPX allows you to directly import MXF media one day soon without third party support (which I have a hunch it will), then you can simply just use the card structure, and it will then become your primary source of media.

I have had problems with Canon MXF media in the past, so, the problem may be on the card, not with FCPX.


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Bob Woodhead
Re: Unusual corrupt clips
on Oct 1, 2014 at 12:34:40 am

I'm not going to be sitting down for a few days, what with all that spanking! But I do have to admit it was deserved. I think my disdain for camera card backups came from years of working with P2 media and FCP7. The original card and imported ProRes were similar in size, so no dramatic space savings there. Between protected RAIDs and backups, footage was secure. Never an issue.

But now with X's HQ transcodes & proxies, I get the advantages of holding on to camera card images of compressed formats.

Still though, it's not unusual for me to shoot with a tethered camera recording straight into ProRes, or RED SSD's, for example. Not going to be making card images from those.

With that last thought, is anyone using a DIT app? Something that confirms/checks data transfers?


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Jeremy Garchow
Re: Unusual corrupt clips
on Oct 1, 2014 at 12:49:28 am

ShotPut pro for me.

They also have a standalone md5 checker within the app so you can copy now and verify later, also handy for large file transfers to/from shared storage/archive.

If you are shooting straight to ProRes, then just back those ProRes files up a few times.

Again, I believe we will see more MXF support in FCPX in the near future so this all may be moot.


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Bill Davis
Re: Unusual corrupt clips
on Oct 1, 2014 at 1:10:30 am

I have Shot Put Pro and use it when I'm the hub of something where multiple shooters are feeding me content. But if it's just me, I'll use SCDI to make a suitable size Sparse Disk Bundle then just copy the root arrangement of any digital media source - card, drive, whatever into it.

With that done, I drag copies to at least two (sometimes 3) mirror drives and finally feel safe.

SPP adds the checksum routine to guarantee bit for bit copying, so if I was videotaping something truly mission critical and can't be replicated, I'd probably go in that direction.

But Standard SCDI card clones have been working for me for 3 years without a single failure.

YMMV.

Know someone who teaches video editing in elementary school, high school or college? Tell them to check out http://www.StartEditingNow.com - video editing curriculum complete with licensed practice content.


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gary adcock
Re: Unusual corrupt clips
on Oct 1, 2014 at 1:40:10 am

[Jeremy Garchow] "ShotPut pro for me. "

Me too.


use It everyday on my current TV series. Moving nearly a TB of content daily with SPP, use it over all other products for my day to day data wrangling.

gary adcock
Studio37

Post and Production Workflow Consultant
Production and Post Stereographer
Chicago, IL


Follow my blog at http://www.garyadcock.com

Or follow me on Twitter
@garyadcock




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