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Is there a way to use keylight to get perfect mattes…problems with spill and edge hardness
I’ve been using Keylight in After Effects to try to get a perfect Matte…I’ve mostly succeeded but I am finding problems with the spill…
My main problem is mostly due to the fact that if I pull the edge in too closely I end up cutting off some fine details (mostly his nose in a wide shot and some detail from his clothes)…but if I don’t I’m getting quite bad spill showing along his skin (and again it is most obvious around the shape of his nose which is making the matte look rather poor).
I am using the Matte Choker and to a degree it has helped by allowing me to soften the edges a bit – though I would have preferred to achieve something sharper – but due to the shape of his head it also tends to give him a bit of a grey-blue halo (and still cut off his nose – the spill AGAIN!!!)
The footage was shot on miniDV with a high end DVCAM (it had 4:2:0 color compression – but unfortunately it was also interlaced) and I’m aware that some of the problems have occured within the camera and the footage.
I was just wondering if there were anymore techniques I could use for cleaning up the edges of the matte outside of tweaking Keylight and the Matte Choker
Is there a way around this? Can
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3 Replies
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You’re discovering the joys of keying highly compressed DV. There are lots of links for this if you use the search option with “keying DV”, and a few recipes to help you. Like this one here
Good luck,
BenCurious Turtle Professional Video
Training | Editing |Support -
Well, cleanup may not at all be the solution here. More likely you can get much better results by doing some cheap trickery. Try this:
a) duplicate your keyed footage.
b) erode it until you get to acceptable clean colored areas
c) dilate those clean edges using the MiniMax effect until they fill up the missing areas.
b) blur the layer
d) use yet another duplicate as a matte (inverted Alpha) for your color layer
e) erode and blur the matte, until your color layer gives a nice “Inner Glow”After that, you only need to play with blendmodes and adjust the hue of your color layer. Multiply, Overlay and Color do wonders. Mind you, the only objective here is to hide the spill, not really get rid of it, but in most cases this is more than sufficient.
Mylenium
[Pour Myl
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Hi Kermit,
There’s some good suggestions here (and I can also wholeheartedly recommend Mark Christiansen’s book as was suggested in one of the links above, if you’re after keying tips and other higher end AE info).
A common technique for Keylight use is to pull your key in a couple of passes…. dupe your footage layer with a basic key on it, then use the top layer to generate a hard edged matte that is eroded in. This layer now contains the solid inner areas of your keyed talent, so that on the lower layer you can just worry about getting the edges right.
Keylight’s pre-blur is designed to help deal with high compression footage as it softens the chroma in the channel used for matte generation only, use sparingly tho.
If you’re still running into issues, feel free to drop us a line at support at thefoundry.co.uk : we’ll get you an ftp account set up where you can upload the footage, and will have a look to see if we can come up with a working solution.All the best
JackThe Foundry, UK
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