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Simon Höfer
06-01-2010, 03:22 AM
Hey guys,

my partner shot some footage with our 7D and we noticed a codec breakdown similar to our GH1. I've never read about that from the 7D before. Is it the codec or probably the write speed of the card or something else? Somebody having the same issue?

Here is a crop of the orginal image:
http://www.dvxuser6.com/uploaded/26393/1275387749.jpg

And another one:

http://www.dvxuser6.com/uploaded/26393/1275388110.jpg

PerroneFord
06-01-2010, 05:14 AM
The codec can certainly be overwhelmed, but this looks like corruption.

Simon Höfer
06-01-2010, 05:26 AM
Thanks for your answer already. So it is probably not the codec that is the problem. So what could be the problem? Write speed of the card? It is a Kingston 16GB x133 card . Should be fine normally, right?

Or probably a file handling problem in the PC? My partner said something that he did defragmentation and lots of file moving.

PerroneFord
06-01-2010, 05:29 AM
I'm guessing it was in the pc. can you go back to the card and look at these files in the camera?

Simon Höfer
06-01-2010, 05:38 AM
Sadly no. Card is empty already.

Everts
06-01-2010, 06:12 AM
I never defragment a videostorage drive or any other drive for that matter....
Usually I just reformat my OS drives .

Simon Höfer
06-01-2010, 07:16 AM
I never defragment a videostorage drive or any other drive for that matter....
Usually I just reformat my OS drives .

Yeah, I guess that was the problem. Well, lesson learned. Good that the footage was not that important.

stephenvv
06-01-2010, 09:39 AM
100% not the codec. The codec is pretty robust - just did some whip pan stuff with extrokewl rolling shutter slanting and saw zero codec breakup issues.

Barry_Green
06-01-2010, 09:41 AM
yeah, I've seen the 7D codec fall apart and it doesn't look anything like that. When H.264 gets pushed too far it doesn't go blocky, it goes mushy. So I think Perrone was on target there, it was likely a data corruption issue, and the only way to really know for sure is to have played back the footage from the card on the camera (which, we know, isn't possible in this case). So it could potentially have been a bad card, or it could be data corruption caused by a faulty copy to the computer. But I really wouldn't expect that this would be a codec fault in the camera itself.

kgimedia
06-01-2010, 10:48 AM
I never defragment a videostorage drive or any other drive for that matter....
Usually I just reformat my OS drives .

I never defrag anymore as I am mostly OS X, but when I was working in Broadcast encoding we had 12 MPEG-2 encoders running almost 24/7. We would only stop them for their weekly defrag. The defrag helped keep our files contiguous and error free.

Simon Höfer
06-01-2010, 11:34 AM
yeah, I've seen the 7D codec fall apart and it doesn't look anything like that. When H.264 gets pushed too far it doesn't go blocky, it goes mushy. So I think Perrone was on target there, it was likely a data corruption issue, and the only way to really know for sure is to have played back the footage from the card on the camera (which, we know, isn't possible in this case). So it could potentially have been a bad card, or it could be data corruption caused by a faulty copy to the computer. But I really wouldn't expect that this would be a codec fault in the camera itself.

Good to know!


I never defrag anymore as I am mostly OS X, but when I was working in Broadcast encoding we had 12 MPEG-2 encoders running almost 24/7. We would only stop them for their weekly defrag. The defrag helped keep our files contiguous and error free.

Hm, I thought this might be the source, but now I am not sure again. We'll see. Maybe we make some tests.

Thanks for your comments everyone!

Postmaster
06-01-2010, 12:28 PM
I defrag my drives after every job and never had a problem like that.
Looks like data corruption thou, but I doubt it comes from the defrag run.

Frank

daveswan
06-05-2010, 02:09 AM
Some time ago, when I was first filming and editing I posted a question about de-fragging media drives on the Avid forums and got a very firm "DON'T DO IT!!!!" in spades", since then (About 2004) I never have.
I do, occasionally de-frag my boot drive.
Dave

ChipG
06-05-2010, 12:06 PM
Some time ago, when I was first filming and editing I posted a question about de-fragging media drives on the Avid forums and got a very firm "DON'T DO IT!!!!" in spades", since then (About 2004) I never have.
I do, occasionally de-frag my boot drive.
Dave

I could be wrong here but it is my understanding not to defrag during a project because it moves the video files around and it makes the avid less efficient when it tries to go find them, you should defrag after any big project (not ever during).


I hangout on the avid forums and this is my understanding, if your drives have never been defrag'd since 2004 you could be on the verge of losing them completely.