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Jagged Edges using Keylight
I’ve captured some interview footage in Final Cut Pro HD that I shot with an XL2 in 16×9 on green screen. I’m kind of new to After Effects so I may be missing something here. When I import the captured files into AE and run keylight, I can pull an excellent key, but the video is incredibly jagged (particulary the edges) and looks awful on a background as if it is severely aliased or interlaced. I have checked to see if it is de-interlacing, and it is (lower). So I guess what I’m asking is am I missing a critical step in importing, or should I be doing something in FCP before using AE to import?
Any help would be greatly appreciated. As I said, I’m pretty new to AE and it can be pretty overwhelming as I’m sure you all know. Thanks!
Behold My Electronic Signature
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2 Replies
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What you’re seeing is the dramatic loss of image resolution due to the DV compression. Basically the color information is subsamled to very low resolution (one quarter of the video res!).
Unfortunately, chromakeying relies heavily on that color information to pull its mattes.
There are a couple of tools out there that attempt to reconstruct the image detail from the pixellated footage. The Magic Bullet Suite has a very good de-artifactor which does a great job. But it comes at a price.
The cheapest option is to smooth out the color information a bit:
1. place the source footage in a comp named “chroma smooth” or something.
2. place an adjustment layer on top of the source and apply a 4 pixel blur.
3. set the blend mode of the adjustment layer to ‘color’.
4. drop the “chroma smooth” comp in a new comp and apply Keylight there.
You’ve effectively smoothed out the colors a bit, while leaving the luminance intact. Not the most high-tec solution, but it’ll do the trick.
Bar3nd
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Thank you much for your suggestion. As far as the 4 pixel blur goes, what type of blur do you suggest as there are many different types? Now if this is a problem with DV compression, would I not be getting the same problem within Final Cut? If I use Final Cut’s chroma keyer, my edges look smooth as can be (just not the best color pull). I didn’t know if I was doing something wrong in route to AE. ANyway, thank you very much for your reply. The Cow Community rocks!
Behold My Electronic Signature
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