8 Replies Latest reply on Mar 19, 2008 7:46 AM by Joey Morelli

    Rotoscoping made easy

    Level 1
      I am assuming this is the correct term.

      Here is the situation I have. I captured some video which was done over a key wall, however, I am getting areas which are transparent where they dont need to be and areas where the person and the wall is merged. Now I have applied the Primatte keyer which has done remarkable work but I still have areas which arent keyed completely. So I have decided to mask around what was messed up, the only problem is that this mask will need to be done frame by frame. I was wondering if there was anything else I could try before taking this long task. And if I must do this frame by frame are there any suggestions on what would make it look at least a little better.

      Thanks!!!!!
        • 1. Re: Rotoscoping made easy
          Andrew Yoole MVP & Adobe Community Professional
          I'd suggest it's very hard to offer suggestions without seeing at least a frame or two of the problem footage. Every keying job has its own story.

          Any chance you could post a clip or jpeg somewhere?
          • 2. Re: Rotoscoping made easy
            Mylenium Most Valuable Participant
            >And if I must do this frame by frame are there any suggestions on what >would make it look at least a little better.

            Well, that one is usually easy to answer: masks with variable feather that can be adapted to the amount of motionblur in a given frame. Unfortunately that's not an AE-native feature and would require you to buy the PV Feather plugin or use other tools to begin with. Ragarding your other problem: Have you considered adjusting color and contrast before applying the key? It doesn't need to look pretty, but will possibly allow you to get a cleaner key around the edges. Youu can then use that sub-comp as a matte on the other clip. Obviously this will be a bit problematic if you need Primatte's transparency keying features for glass and hair, but it might be worth a try.

            Mylenium
            • 3. Re: Rotoscoping made easy
              Jonas Hummelstrand Level 2
              Experienced keyers know that being able to pull a good key in a single pass is very rare.

              I'd suggest you apply Primatte on one copy of the footage and tweak it to make sure that there are no holes in the body (called "core matte") and another instance of Primatte on a duplicate layer that just deals with the general outlines, and a third (or more) that deals with problematic areas such as hair.

              - Jonas Hummelstrand
              http://generalspecialist.com/
              • 4. Re: Rotoscoping made easy
                Level 1
                So if you get all of these layers created I am assuming that you would want to use some type of blending mode right?
                • 5. Re: Rotoscoping made easy
                  Mylenium Most Valuable Participant
                  Blendmodes are mostly irrelevant. All you are looking to create is a clean Alpha channel which you will use as an Alpha matte on the original, untreated footage. The only concern is semi-transparent areas adding up at the edges, but this can be compensated by using Simple Choker and other tools to "inset" the edges on the top layers so they don't contribute to already existing edges below. For the actual blending of multiple layers you will use the Alpha Add mode mostly to get linear transprency behavior. As I said - the comp where you are building your Alpha does not need to win any beauty contests - Increase the contrast on layers, clean up the background tones, use multiple keys with different settings, use all other "dirty tricks".

                  Mylenium
                  • 7. Re: Rotoscoping made easy
                    Level 1
                    So far this is what I have come up with
                    http://www.zone91.com/screen.jpg

                    I have noticed something that troubles me (and what I was trying to get rid of to begin with). Along some edges I see what look like waves on water going across. How would you correct that without losing everything?

                    Also I have blue spill pretty bad. I have applied a spill remover on the untreated video but it doesnt do a very good job.
                    • 8. Re: Rotoscoping made easy
                      Joey Morelli Level 1
                      Add a Matte Choker