6 Replies Latest reply on May 29, 2016 9:49 PM by chrisw44157881

    Green Screening Problem

    Broughnut Doughnut

      Hi, I'm green screening a few different videos, and I'm using Keylight. When I key out everything and play the final result, the edges around the subject are very wavey and moving very fast. It's really distracting. I've watched other people key footage and they don't seem to have this problem. Does anyone know how to fix this? [I should mention that the green screen is pretty bad]

        • 1. Re: Green Screening Problem
          Mylenium Most Valuable Participant

          Without seeing your footage and your Keylight settings nobody can advise. Most likely you simply need to create garbage mattes to help matters along or use a different approach entirely like generating a matte using channel calculations on a heavily tweaked duplicate of the footage...



          • 2. Re: Green Screening Problem
            Broughnut Doughnut Level 1

            Screenshot_1.pngScreenshot_2.pngScreenshot_3.pngScreenshot_4.pngAlright so I'm a bit new to AE, but this is the subject, the settings(basically i only messed with black and white levels), and it's kinda hard to tell but you can see the different lines at different frames of the arm. I also tried simple choker to cut it off, but then the wavey lines just moved inside more

            • 3. Re: Green Screening Problem
              Mylenium Most Valuable Participant

              Your footage seems very low res and soft to begin with. I'm afraid this sin't going to improve much. The only obvious thing beyond that in your settings is that you "clipped your ranges to death" without using any rollback and of course the rather cyanotic green doesn't help. It would be best if you considered reshooting.



              • 4. Re: Green Screening Problem
                Broughnut Doughnut Level 1

                Thanks for your answer, one more thing. What is roll back?

                • 5. Re: Green Screening Problem
                  Rick Gerard Adobe Community Professional & MVP

                  It looks like your footage was not shot on a professional camera with little or no compression. This makes keying more difficult. To find some excellent Keylight tutorials that will show you how to use the controls type Keylight in the search help field at the top right corner of AE and follow the links to community resources. You'll find better info from the Adobe community than you will get from a google search because there is at least an attempt to vet the training.


                  The search help field is one of the most powerful tools you'll find in AE. I use it all the time to make sure I'm not missing a new or improved technique.


                  BTW, thanks for the screenshots but a frame of the original footage would really help point you in the right direction. It looks like you have a highly reflective surface and I've found that these usually require several instances on keying, masking and color correction to fix. I doubt I could fix your shot with a single layer.

                  • 6. Re: Green Screening Problem
                    chrisw44157881 Level 4

                    i'm just guessing what the video looks like but I believe you're running into the old problem called "boiling"

                    you can use rotoscope's tool "refine matte - Reduce chatter" to fix this. Basically, key loosely and rotoscope to fine tune.


                    "reduce erratic changes to edges from one frame to the next. This property determines how much influence the current frame should have when performing a weighted average across adjacent frames to make the matte edges not move erratically from one frame to the next."


                    Roto Brush and Refine Matte in After Effects

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