4 Replies Latest reply on Jun 8, 2016 12:55 AM by LujanSolo

    Background Footage Layer Shake


      Hello Adobe Hive,


      Here's the situation:


      I have footage that has a house in a field, and the house has to go, to be replaced by a field, which I'll be cloning from another piece of footage (another angle on the same field without the house).  So, at the most basic - it's a footage layer on top, the house masked out, the other footage on the bottom layer, allowing the cloned field to take the place of the house.


      Here's the issue:


      *Everything* I've tried (rotoscope, basic masks, using a still jpg instead of background footage, 3d Camera Tracking coupled with Ground Planing, Camera Projection + Grid Placement, etc) leaves me with a background layer that shifts position up and down.  Why, you ask?  The camera is a push in on an actor under said tree, meaning the perspective changes as the push occurs, of course.  Regardless of any motion tracking I do, I can't resolve this shaking issue.


      I'm sure I've missed something basic, but after two weeks of trying and failing, I need your help!


      Thank you in advance.

        • 1. Re: Background Footage Layer Shake
          Mylenium Most Valuable Participant

          Without seeing your footage nobody can tell you much. Your failure quite likely is that you are looking for a one-step solution while from the sound of it, your setup would require like a gigazillion steps all combined.



          • 2. Re: Background Footage Layer Shake
            Rick Gerard Adobe Community Professional & MVP

            I would start by using Motion Stabilize rather than tracking. Pick two objects in the same plane in the footage where you want to replace the house in the shot where the camera moves in and track position rotation and scale then apply the stabilization. Now the objects that you tracked to motion stabilize should not move. Now add a layer to use as a track matte to remove the house and your replacement footage if it is locked off and the camera is not moving at all. If the replacement footage sticks to the stabilized footage just fine then you should be ready for step 2. If it does not then you need to animate position, scale and rotation so that the replacement footage looks right.


            Step 2 involves removing the stabilization from the stabilized shot and adding the motion to the track matte and the replacement footage. This is easiest to do by adding a null and then tying the position of the null to the Anchor point of the footage that has been stabilized. That's the easy expression. Now you have to apply the opposite of rotation of the stabilized footage to the null. This is also easy because all you have to do is add an expression, add a minus sign, then drag the pickwhip from the null's rotation to the stabilized footage. The last expression is scale. This one is a little more complicated. To make things easier just apply this animation preset to the null after you name your stabilized footage "stabilized" and then move the CTI to the first frame and parent all of the layers to the null.


            Here's the animation preset: Dropbox - destabilize Rotation Scale.ffx


            If that doesn't work then the next trick I would try would be to camera track the footage. The trick there is to pick points in the same plane where you want to put the replacement footage to cover the house. The problem is that you may have a bunch of parallax difference  between the house and the replacement footage. If you do then you will have to apply a 3D layer to the scene in the same plane as the ground you are going to replace then use a point light and a scaled copy of your footage as a projector to projection map the replacement footage onto the 3D layer. This is too complicated to explain in a post. 

            1 person found this helpful
            • 3. Re: Background Footage Layer Shake
              LujanSolo Level 1

              Excellent!  Thank you, Rick, for interpreting my post.  I appreciate the time you took to write all of this out for me.  I'll be back to work on it tomorrow, and will let you know how it works out!




              • 4. Re: Background Footage Layer Shake
                LujanSolo Level 1

                Just tried out step 1 really quick, and the background/replacement footage  sticks and is all good.  I'll do the rest tomorrow, as I'm looking forward to finally getting this done!  Well done, Mr. Gerard!