Author Topic: Raw video Mark II jagged edges  (Read 5626 times)

nofare

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Raw video Mark II jagged edges
« on: June 28, 2014, 01:42:51 PM »
Hello,

Used a Mark II to record some test footage over the weekend. I'm getting a lot of lines on the image. The more contrast in the footage, the more visible they are.

Got one the .mlv files through post without any correction whatever, and got a video out.

Here's a screen capture of the info I get through the mlv viewer.
http://www.tiikoni.com/tis/view/?id=9dc7b8c

And here's a hi-res screen capture of the video after export through After FX.
http://www.tiikoni.com/tis/view/?id=ea553eb

What are those lines and how may I get rid of them, or at the very least, reduce them?

Thanks.

jimmyD30

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Re: Raw video Mark II lines
« Reply #1 on: June 28, 2014, 03:48:26 PM »
What part of these images are you seeing lines and are they vertical, horizontal, diagonal and color? Cause I don't see any lines which you refer to.

nofare

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Re: Raw video Mark II lines
« Reply #2 on: June 28, 2014, 07:53:10 PM »
Maybe lines is not the right term. Let's call them "jagged edges" instead.

If you look at the shiny parts of the bike's frame, you'll notice that the edge of those parts is not smooth but jagged, like some sort of aliasing.
Those jagged edges are present all over, but are most visible when you have very harsh contrast between the brightest spots and the darkest.

Midphase

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Re: Raw video Mark II jagged edges
« Reply #3 on: June 28, 2014, 09:09:19 PM »
I think that's just the 5D2's line-skipping aliasing at work. You're just noticing it more now since you're looking at footage with a great deal more detail.

jimmyD30

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Re: Raw video Mark II jagged edges
« Reply #4 on: June 28, 2014, 09:10:38 PM »
I see what you're talking about now, mostly around the blown out highlights (specular). There could be a few things going on here, especially related to the highlights (search this forum for highlight aliasing, etc.), but I don't remember exactly what the fix was.

But for sure, try using 3x digital crop mode (even if just for comparison and problem solving reasons). This feature eliminates line-skipping in the video capture and therefore all of the aliasing and moire related to this DSLR phenomenon are eliminated too.

nofare

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Re: Raw video Mark II jagged edges
« Reply #5 on: June 28, 2014, 09:14:08 PM »
Midphase and Jimmy, thank you both for your insights.

Will try 3x Digi Crop on a similar sort of shot and see if I can get better results.

Now off to peruse the forum further for that highlights aliasing issue.

nofare

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Re: Raw video Mark II jagged edges
« Reply #6 on: June 28, 2014, 10:07:09 PM »
Another thing that I'd like to add is that I shot at 960x540. So as soon as you look at your image at 1920x1080 whatever video artifact you have in there will be that much more visible.

ted ramasola

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Re: Raw video Mark II jagged edges
« Reply #7 on: June 29, 2014, 03:18:43 AM »
Those are typical color aliasing and moire issues of the 5D2 and most older canon dslrs due to line skipping. Shoot a brick wall or an ac grill or transmission lines and you'll see them. Its always been there but more obvious since you shot in low resolution. Look up mosaic engineering VAF filter if you want to control these issues.

 
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Texas

nofare

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Re: Raw video Mark II jagged edges
« Reply #8 on: June 29, 2014, 11:48:27 AM »
Yep, it all makes sense.
And although I've heard of the anti-aliasing filter you mention, I'll skip it and instead invest in faster cards which I'll use with my Mark III.

Thanks Ted.

jimmyD30

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Re: Raw video Mark II jagged edges
« Reply #9 on: June 29, 2014, 01:06:59 PM »
Yeah, that anti aliasing filter works pretty good, but there are some minor drawbacks to using it (plus it's expensive!).

Basically, anytime you can use 3x crop, you should, because it all but eliminates aliasing and moire.