GH4 File corruption - SD card issue?

I

Ian Stark

Active member
I shot 46 clips yesterday onto a Transcend 128gb SD XC speed class 10/UHS class 3 card in a GH4. The first five clips are corrupted but the remainder are fine. They do not play back in camera but when transferred to a pc the audio is fine. I am guessing that the fault lies with me in using a 128GB card, given that the GH4 only officially supports 64GB - something I only just thought to check :-(

Here are the facts:
  • Rec Format: MP4 (LPCM)
  • Rec Quality: 4K, 3840x2160, 24p, 100Mbps
  • I had previously successfully used the Transcend card and all appeared fine for stills and video at 4K and C4K (and below). In fact I used two of them on an overseas shoot a couple of months ago and had no issues shooting at the same quality. Naturally I had tested them beforehand, although I regret that I didn't think to check that the GH4 supported that size card. Clearly the card's performance rating is sufficient.
  • I was monitoring via HDMI/Atomos Connect to a Samurai Blade which was also recording, thankfully (albeit in HD). The clips recorded to the Blade are all fine so the video stream was successfully leaving the camera's processor.
  • Audio plays back OK in VLC but Windows Media Player (or whatever it's now called in W10) cannot play it at all.
  • When I tried the clips in Quicktime I got the message "error -2041: an invalid sample description was found in the movie"
  • Importing into Sony Vegas just brings in the audio track.

Can anyone please confirm or deny that my wrong choice of card is to blame or add other suggestions as to what went wrong with those clips and why the others on the card were fine?

Thanks.

p.s. suggestions for devices that do work with 128GB cards also sought ;-)
 
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Hi David,

Interesting point. I did indeed format the card (in camera) but I took a bunch of stills on the set which I then deleted (in camera, immediately). I didn't reformat after taking the stills. Are you shooting 4k?
 
Thanks for the suggestion Al. Just tried it but sadly no luck. Reading through the instructions it suggests it's for AVCHD, DV and pictures only but I thought it was worth a try. Nice idea though :-)
 
Thanks for that - to be honest I'm more keen to know if it's a problem with the card or camera, or something I am doing wrong, rather than trying to fix these clips (and I do have HD versions on the Blade which I have now used in the project). But useful to know all the same.
 
While Transcend is probably the best of the "bargain brand" media cards, it is still "bargain brand". I've followed this card "quality" issue since 2009 and while Transcend has a better record than others I still have seen complaints like yours a bit too often to cause me to not even consider trusting that brand, although many swear by it and have had good luck.

I'm not a "brand snob" and would like to save some money if I could.

But I use nothing but SanDisk, the only corrupted file I've seen turned out to be a built in reader on the computer going bad, a $24 external reader that connects to the computer's USB port solved that problem. SanDisk quality control is better and they have a lifetime warranty (make sure you purchase from a reputable dealer and save reciepts or invoices - I purchase from B&H).

Some tips...

Panasonic cameras do not seem to offer a low level format choice, so about every 5 uses or so I do a low level format on the media card in a PC followed by a format in camera. The quick format done in camera only zero's out the File Allocation Table on the card but leaves file data scattered in "chunks". Over time this "clutter" builds up and slows down the media and ultimately can cause corrupted files.

A bit of this may be what happened to you. SanDisk will let you get away with it longer but eventually it can happen again. The low level format seems to help prevent this as it zero's everything on the card out.

I do a low level format on all cards to be used on any important project then format each in camera before heading out on location. Hope this helps.
 
Thank you Bruce, very useful. Over the years I have used various brands, including Transcend, Sandisk and PNY and this is actually the first time I have ever encountered any problem. Having said that, I haven't been shooting in 4K for very long, so the load on the cards was significantly lighter. I will certainly be taking your advice!
 
Ian Stark said:
Hi David,

Interesting point. I did indeed format the card (in camera) but I took a bunch of stills on the set which I then deleted (in camera, immediately). I didn't reformat after taking the stills.
Click to expand...

I suspect the issue was caused by deleting (the stills) and then not reformatting before shooting again rather than issue with the cards.
 
As a curiosity, try downloading the files again to another machine. I had three corrupted files yesterday with a Sandisk Extreme Pro U3 card that came back to life on a different machine and play perfectly there. I will try to transfer them back to this drive and see if they are OK here as well. That was my first time having an issue with the GH4 as well.

Cheers,
Pete
 
Bruce Foreman said:
Panasonic cameras do not seem to offer a low level format choice, so about every 5 uses or so I do a low level format on the media card in a PC followed by a format in camera. The quick format done in camera only zero's out the File Allocation Table on the card but leaves file data scattered in "chunks". Over time this "clutter" builds up and slows down the media and ultimately can cause corrupted files.
Click to expand...

I agree. Panasonic does endorse this pc/Mac SD Formatter program:
https://www.sdcard.org/downloads/formatter_4/index.html

See:
http://av.jpn.support.panasonic.com/support/global/cs/sd/download/

Al
 
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And thanks Al for the link to the formatting utility. Up until now I have only ever used the in-camera formatting facility. I'll be changing my ways!
 
I'm sorry if I missed it, but have you tried to replicate the problem? that is, format the card and reshoot various shots, and see if any of them are corrupt as well?
 
Not had a chance yet, but the card is currently in an envelope marked 'TEST BEFORE USE' :-). I was actually holding out for a possible save of the corrupted files but that's looking unlikely now. As soon as I get an opportunity I will test it and report back.
 
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