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SERIOUS P2 Transfer Data Corruption Issues.

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Kevin Brusie
SERIOUS P2 Transfer Data Corruption Issues.
on Apr 20, 2009 at 2:40:22 am

I just added the 170 and shot my first job with it. I tested workflows and after problems with G4 Powerbook crashing during transfer using using ShotPut Pro... being told NOT to use drag & drop, and unable to find P2CMS for G4... I opt for my windows XP machine to a NTFS Raid1 USB/FW800/400 Guardian Max drive.... Mac OSX can read NTFS... no need to write to it. We cut in FCP6.

So I thoroughly shoot test footage, HD 1080,720p,sd480p... and use P2CMS on Windows to copy. Works great. Test the drive in FW400 (4pin) and transfer is deadly slow... test again on USB 2.0 and it is what I hear advertised about a gb per min for HD. Bring footage in... FCP loves it.. All is well with the world.

Thursday & Friday are first production days for paying gigs... Thursday I off load as I shoot to my drive, using P2CMS Export, with "Compare"... All seems well. Minimal checking is done as we off load due to.. well... we are shooting. We don't exceed our two cards, so I return to the editing suite Thursday PM and plug the camera in via FW to the MacPro and copy the files to the main raid storage. I feel good. Verified data on the raid 1 field drive and on the editing suite drive.

Friday, again we don't exceed out two P2 cards... so I download as we strike the set to the laptop/raid1... then return to the editing suite. This time in lieu of offloading from the P2 I opt for getting the data from the field raid drive. Mac OSX ses the NTFS drive just fine... I copy the folders over... Log & Transfer... and the footage has all sorts of digital artifacts randomly appearing throughout... some we shot SD (DVC50) other 720/30PN. It is in both... It looks like what happens when your digital cable signal is low... a single frame with 6 to 8 blocks of digital noise clumps (about 4 to 6 pixels each). Just a single frame. I look at the footage on the P2 (thankfully not erased)and it is fine. I recopy from the camera to the editing machine and ALL clips are fine.
I plug the field raid drive into the Windows laptop and use P2 viewer... and the footage is screwed there. So it was not the copy to the mac, but from the P2 to the Raid drive via USB. This was with the "compare" checked. So much for data verification.

Does anyone have a clue how this could be happening especially since the "compare" is checked? My limited knowledge of file structure says this should not be possible. Even for the frame to be visible with those random noise bits seems hard to imagine.. It should be either readable or not, no?

Help me out here folks... I need to sort this one out fast as the next job will undoubtedly over run my 16gb &32gb P2 arsenal...

Thanks in advance...

kevin

Kevin Brusie
http://www.kevinbrusie.com
http://www.wonderdogfilms.com
DVX100A & HPX170


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Kevin Brusie
Re: SERIOUS P2 Transfer Data Corruption Issues.
on Apr 20, 2009 at 11:22:21 am

And I forgot to add that a test from the P2 copying to the XP laptops internal drive via P2CMS yielded the same problems.

kevin

Kevin Brusie
http://www.kevinbrusie.com
http://www.wonderdogfilms.com
DVX100A & HPX170


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Ethan Sigman
Re: SERIOUS P2 Transfer Data Corruption Issues.
on Apr 29, 2009 at 12:04:34 pm

if you do some searching on "the glitch" you might find some examples of this. it exists, despite being very rare. i experienced it a couple times with my first hvx200. i posted pics on my free production page at productionmeeting.com...... you can see the picture of the example here:

http://www.productionmeeting.com/photo/2039668:Photo:1701?context=user

most people have not seen it nor will they know what you are talking about. the only way around it that i know of it is to minimize your use of those frames in the project then go through frame by frame and sample the area to knock out the digital spec pixels...

ethan

http://www.EZSproductions.com
http://www.productionmeeting.com/profile/EthanSigman


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Kevin Brusie
Re: SERIOUS P2 Transfer Data Corruption Issues.
on Apr 29, 2009 at 2:10:39 pm

ethan,
Thanks for responding. Yes, that is exactly what I am seeing (your frame on productionmeeting). After an exhaustive analysis of everything around that footage... especially since it did not happen again since on other shots...I have a theory: electromagnetic field interference. Now I am not a physics sort of guy...nor an electrical engineer, but it appeared at two different times. It was during a shoot for a medical center. Turns out the footage was shot either while or right after being very close to MRI and Radiation therapy equipment. Both of these use massive amounts of power and I can feel the charge in the air when I am close by. (The rest of the folks present thought I was bonkers, but I feel strong EMFs) I have shot digital still many times near this type of equipment with no ill effects. But for some reason.... This appears on cards that were exposed to these fields. Interestingly even if the footage was shot after we left that zone (or at least I thought so).

So any techno wizards out there care to comment on my theory?

kevin


Kevin Brusie
http://www.kevinbrusie.com
http://www.wonderdogfilms.com
DVX100A & HPX170


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Stephen Deaver
Re: SERIOUS P2 Transfer Data Corruption Issues.
on May 16, 2009 at 2:18:53 pm

I encountered this exact same problem recently (the corruption looks just like the frames posted). Using a PC laptop with XP, transferring from the PCMCIA slot to external hard drive using USB. Footage on cards was fine, but footage on drive included these artifacts randomly. The artifacts are difficult to detect using P2 viewer (which does not play back every frame on my system).

I have used the same procedure for transferring P2 footage for three years. I have transferred hundreds of P2 cards with no problem, including a feature film with dozens of hours of footage. No lost clips, no dropped frames. Now this.

I switched out external hard drives. I switched out cables. I switched out laptops. Still no dice. Blaming an environmental factor like an EM field could make sense, but it would feel like passing the buck.

The only workaround I can think of would be to copy each card twice, so that randomly induced errors would be in different spots. But there simply isn't time for that in most shooting environments. And it shouldn't be necessary.

I'd love to hear if anyone else has this problem, and if they found a solution.


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Kevin Brusie
Re: SERIOUS P2 Transfer Data Corruption Issues.
on May 16, 2009 at 5:07:43 pm

Stephen,
I agree that the EMF theory seems like "passing the buck".. But... it was the only variable in the mix. I have since shot another three hours of footage and have not had an issue... (not a lot of time, I admit)... I have also switched from the XP based transfer system, which was using the Panasonic software, to a G4 Mac Powerbook, using ShotPutPro to an external HD via FW800. This is the same HD I had been using but I have formatted it to Mac os ext now in lieu of the PC format (not FAT32 but the other... whose acronym escapes me now...)

I, too am curious as to what the REAL culprit is...

kevin

Kevin Brusie
http://www.kevinbrusie.com
http://www.wonderdogfilms.com
DVX100A & HPX170


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