View Full Version : About primatte and masks
02-11-2005, 08:58 AM
I'm doing a bit of keying at the moment and there are a few not so good shots of which I need to extract the actors from. I put a mask to the footage that only includes the actors and a bit of extra space and then used primatte to take out the blue.
Now, this results that I have a black rectangle surrounding the mask shape (in the output of primatte that is). So, I put the same mask to primatte as well. This gets rid of the black box but now I get artifacts along the edge of the rotoshape.
I've tried to mess with the soft edge (tryuing to remove it that is) but I do not seem to get this work for some reason. Any help from you pros?
02-11-2005, 06:35 PM
well...when green/blue screen is not that good, i follow following steps:
if it is a NTSC video, the color output is 4:1:1, i take it to finalcut pro and export it as uncompressed 8bit 4:2:2, that way get more information about blue/green along the edge...if u dont have finalcut, ignore this step
now in shake, before matting, put a blur node and blur only the b(or green), instead of default rgba, that way it will smoothout the blue edge.
then matte it, but dont put backgroun now
give a final touch with with bluring the alpha now(blur node, this time only a)
put the background with a under node
it should work now
best of luck
02-15-2005, 04:32 PM
It seems I'm a bit bad with explaining things. And being a bit impatient. So, the answer to myself: Either put up constrast a great deal, multiple thousand percents like I did, or be smart and use the Inside node. That get's rid of the jagged edge on rotoshape. One more option is to invert the rotoshape and put it to Primattes garbage-matte input.
Sorry about the double posts, I put this reply to both of them just in case somebody else ever reads and ponders those things.
Edit: Thanks for the reply still. Even if I did not try it out and it seemed to answer another question about keying, my thanks about trying to help out. :)
02-15-2006, 05:00 PM
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