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Footage becomes blurry during field render
Hi
I’ve been having problems field rendering footage that has been keyed. This problem only happens when the footage is moved using transform – it is sharp when no transform is done. So, if I just shift the image over a bit, it becomes blurry during field render output (I’m not talking about when it’s moving, but anytime after that shift).
The footage was shot on beta, captured uncompressed 4:2:2, and keyed using Ultimatte, then output using field render, Uncompressed 422 with Alpha.
The problem is not with the initial key, which looks good, it’s when I take that key with alpha and place it within a composition and do a transform on it. It gets so blurry after a simple transform (ie moving it slightly to the left, for example) that I’ve been having to use Frame render to get rid of the blur, but I’d rather be using field render.
I tried a test with the unkeyed footage directly, and it looks fine when a transform is done and field render is used.
Any ideas?
Thanks much.
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7 Replies
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sounds like motion blur enabled. switch it off in render output settings.
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Dave,
In Fields and Pulldown, Separate Fields is set to Lower First (and I used Lower first when making the key with alpha too).
Remove Pulldown is set to Off.
Also, this is not a motion blur issue, the footage becomes blurry after it is moved and then is no longer moving.
Any other things to check?
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I just changed the interpret to Upper First and the blur goes away, but now its a bit jittery.
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Now I’ve changed the output of the field render to upper first, and the jittery goes away, but it’s back to blurry again. The same happens when I do the opposite, interpret lower first, and set render to upper – always not blurry when they are opposite, but jittery.
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Dave,
I just noticed that when I cut the keys with alpha the interpret on the original footage was set to none. I think changing this to lower is working.
Why would this be set to none? Could it have to do with how it was imported?
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Dave,
I was wrong about that fixing the problem. I just changed the interpret on the original to lower, exported the key with alpha, made sure the interpret is lower for the new comp, and when exporting field render (lower), it still gets blurry. Very frustrating.
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“I tried a test with the unkeyed footage directly, and it looks fine when a transform is done and field render is used.”
Try rendering out the keyed stuff separately then importing it post-keyed. Now transform it. Or maybe a Pre-comp would fix it. Precomps fix lots of stuff.
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