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Seriously Disturbing - SDHC file corruption

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Charles Wannop
Seriously Disturbing - SDHC file corruption
on Aug 9, 2010 at 12:53:38 am

I have just finished shooting a two day conference - about 5 hours of sessions per day. I bought two Sandisk 32 gig cards (class 10) a couple of months ago, I added two new ones for this shoot. Day 1 went off fine. I downloaded (via a Sandisk Express reader) and made multiple copies on external disks (and internal drive).
Day 2 I reformatted the SD cards and started shooting. At morning tea break I changed cards and started downloading the first sessions. 329.6 meg into the third clip I got a finder error that the contents could not be read (error code -36) and the card was unmounted. Panic! I found that it was one particular clip that seemed to be the problem, all other clips copied fine. The broken clip would preview fine, I could skip through it and as long as I kept away from 1:19 it would play - something in that region would cause the error code.
I managed to use Mpeg StreamClip to export around the "death-zone" so I have lost only a few seconds of material.
BUT the second card of the day also has a corrupt clip on it and I am about to go through the same process to rescue what I can (these were the cards that I bought a couple of months ago and have used maybe a half dozen times max). The rest of the day went smoothly with the new cards and I *think* I am going to be able to get away with it but this has really shaken my confidence in shooting to SDHC.


Charles.


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Lou Caputo
Re: Seriously Disturbing - SDHC file corruption
on Aug 14, 2010 at 4:27:41 pm

I've never tried 32 gig cards in the camera. I thought the most they recommended was 16 gb cards, although I could be wrong.


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Peter DeArmond
Re: Seriously Disturbing - SDHC file corruption
on Aug 14, 2010 at 5:00:34 pm

Officially, JVC recommends using class 6 or higher SDHC cards, and anywhere from 4 to 32 GB.



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Charles Wannop
Re: Seriously Disturbing - SDHC file corruption
on Aug 14, 2010 at 11:47:03 pm

Ok, this is going to take a bit of explaining, so just bear with me ☺

As I reported earlier, after 13 months of happy operation, I started to get clips that were damaged out of the HM-100. The damage meant that the clip would not transfer to the host (Mac or PC) on the Mac it caused the SD card to un-mount during the read/copy process. The clip looked all right and could be ‘quick looked’ safely, right up to the point of damage. Using MPEG Streamclip I was able export ‘around’ the site and so didn’t loose anything crucial…this time. It seemed to always be a single clip that was damaged, so less than a second’s corruption on a 1h53min card. I finally found a pattern and was able to reproduce the fault. It comes back to using the Mac to erase the card using the Disk Utility (I realize this might sound like a dumb thing to do – but as they say “It seemed like a good idea at the time). So…

1) Erase card using Disk Utility
2) Insert card into HM-100
3) HM-100 wants to re-format – Say ‘Yes’
4) Card *may* reformat OK, or show an error, if so I formatted again in the camera
5) Either way, use card as normal – No error codes reported during shooting.

Now the crazy stuff, cards that showed the error worked perfectly, cards that re-formatted ‘correctly’ the first time ended up with clip damage. Damaged cards reformatted in the HM-100 worked perfectly subsequently.

If the card is erased in the Mac (haven’t been able to test on a PC) you must re-format it TWICE in the camera to avoid ending up with one clip on the card being damaged.

So the good news is that both camera and cards are alive and well and I can relax again.


Charles.


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Will Granzier
Re: Seriously Disturbing - SDHC file corruption
on Aug 24, 2010 at 5:50:47 am

Hey there

This is pretty weird, I had a similar situation with an SDHC on a normal Nikon. I replaced the card and that solved the issue. It might just be card related.

Did you have the problem before you got the new cards to shoot the conference. Was it only the new cards that had the problems.

If I may ask, what brand were they ?

Regards


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Charles Wannop
Re: Seriously Disturbing - SDHC file corruption
on Aug 24, 2010 at 6:43:21 am

Hey Will,
Weird is right!! I first noticed it on my two new Sandisk 32 gig cards (I now see that it was the pre-use testing and re-formatting that I did in my Mac before use that must have caused it), then my older Sandisk cards behaved the same way (again, once I had erased them in my Mac). So I really cant blame the cards here, just my screwy workflow.

Charles.


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