3 Replies Latest reply on Jan 3, 2010 2:35 AM by vfxwizard

    Basic keying question

    Navarro Parker Level 3

      I really like using Conduit for my keys. I think it's cleaner and has less post processing than Keylight. And the unique Unspill node surpresses green faster and more interactively than anything else I've used.  And hey, nodes are cool!


      However, I occasionally run into this problem where I get a white fringe. (It would actually be green fringe if not for Unspill)


      <img src="http://i175.photobucket.com/albums/w134/navstar/conduit-setup-7.jpg">


      I'm so scared of thinning or feathering edges and losing fine detail like hair. And tips on improving the edge? It's 4:2:0 XDCAM EX footage, so I'm not sure if I'm asking too much from the footage or not.

        • 1. Re: Basic keying question
          Mylenium Most Valuable Participant

          Deinterlace? Most of that looks like semi-transparent leftovers from fields. It should be possible to selectively deinteralce the edges after the key and then clean them up. Take your existing key, duplicate it, erode/ choke the top layer, assign it as an inverted matte to the bottom layer. the remaining "stroke" can now be deinterlaced. Then do the same erosion thing with the original key's edges, add slight feathering to both constructs and stack them on top of each other. the cleaner deinterlaced edges would now replace the original ones...



          • 2. Re: Basic keying question
            Navarro Parker Level 3

            Good tips.  But in this case, I'm only working with 1080/30p footage.

            • 3. Re: Basic keying question
              vfxwizard Level 1

              It's hard to say looking at the picture because it has already been chroma keyed and the jpeg compression adds more artifacts, but it looks strangely similar to the 4:2:0 "pal progressive" chroma bug (which, as Mylenium said, looks like interlaced video -yet it appears on progressive footage).


              Can you post an uncompressed, unkeyed frame? I'm wondering if it can be fixed with the free plugin from "Zap" Andersson, Chroma Switcheroo (windows only, found at http://www.lysator.liu.se/~zap/aeplugs/ ).


              Regardless of the above, there's a lot of ringing in the belt, turning coring/sharpening down when shooting would help a lot with chroma keying.