H.264 and artifacting? - T2i

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djbobbyrhodes

Well-known member
Hey all,

I recently did some filming at the Chicago Auto Show, and I'm noticing that a lot of my footage has some pretty nasty artifacting. Any idea what could be causing this? My only guess is that with all the color and shininess and stuff going on in the back is causing the codec to reach it's limit? Or maybe camera overheating something? I don't know. Just needing to vent a little bit. :furious3:

A lot of the footage is going to require some interesting editing if denoiser can't clear this up.

Sexy time photo to cheer myself up:

View attachment 30113
 
are you sure it's codec artifacting and not low-light noise?

I ran a lot of ISO tests last week, and found that flat and smooth surfaces, like the pale-green walls on my living room, can create very noticeable noise even at ISO 400

also, flattening the input images (in extreme cases, by tampering with curves in the picture profile to reduce contrast) increases dynamic range but also adds noise in the graded final image, so if you want as little noise as possible then don't shoot flatter than you need
 
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You mean the blocks that look like corrupted/missing data on a stream?
I usually blame those on encoding errors when I see it on youtube, etc.
Are you sure it was like that out of the camera? Because that's not normal, to my knowledge.
It looks more like an actual chunk of data missing from the file than an h.264 artifact.

You get things like that when downloading a bittorent, for example, and try playing it before the file has finished downloading. Or if the file is corrupted.
Usually you find them with online encoding services like Youtube because of on-the-fly compression discrepancies.
But you shouldn't be getting that out of the camera files.

Maybe your SD card has bad sectors?
 
Yeah, that was in the raw footage. Hmmmmm.....Perhaps a buffer error? This is the first shoot where I accidentally forgot to format my card before hand. Near the end of the day, I had to manually delete some old footage off of there. Maybe that created fragmented space on the card which resulted in the loss in data?

You mean the blocks that look like corrupted/missing data on a stream?
I usually blame those on encoding errors when I see it on youtube, etc.
Click to expand...

That's why I thought it was a codec error.
 
ok, that's definitely corrupted data

it can come from a faulty SD card, a faulty HDD, or even a faulty camera, but in my experience the most common source for this kind of errors, by far, is the SD-to-HDD copying process

if you're on windows, after copying the files, you can test whether they are identical to the original ones with an "fc /b" on the command window

I've got two card readers; with one of them, I get binary errors on nearly half of the files of more than 200MB; with the other one, it's nearly ok, but still it's not common that I get a full 32GB card copied without at least a few errors

most of these copy errors are harmless, some create the effect that you're seeing

that's one lesson I learned while creating my Similaar Card Reader software, which I use to organize my files and make sure that files are copied without errors:
http://www.dvxuser.com/V6/showthrea...-for-copying-your-SD-CF-card-to-your-computer
 
Have you tried streaming the clip directly from the card using bridge? Is the card a high enough write speed to record video? Could be another possible cause. But Normans explanation seems most accurate.
 
Wow. Maybe I'm old fashioned, but I always just transfer the files directly from the camera. I've never had a transfer error yet.

Also, I have observed the noise on plain colored walls too. I think the noise was there the whole time, but with only a solid color in that part of the image, the noise becomes more apparent.
 
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