7 Replies Latest reply on Apr 11, 2015 8:01 AM by Rick Gerard

    How best to motion track blurry footage

    chrisj71

      I am working with After Effects 5.5 with built in motion tracker.

       

      I have a clip with motion, blur and focus changes.  I need to place a composite of a digital clock in the background.

       

      I can track segments of the footage successfully, but still get a bit of shifting from time to time.

       

      Is there a way to track the whole clip without additional software?  I also have Mocha for After Effects.

       

      My experience is limited, I have only been working in AE for about 8 months.

       

       

      Message was edited by: Chris Jensen

        • 1. Re: How best to motion track blurry footage
          Mylenium Most Valuable Participant

          Not really. Such stuff would usually be done using 3D trackers, if the support variable focus/ focus shifts. If adding a clock was always the plan, you should have planned the shot differently. Feel free to use a current AE CC trial and see if it works.

           

          Mylenium

          • 2. Re: How best to motion track blurry footage
            Rick Gerard Adobe Community Professional & MVP

            For that shot I'd stabilize rotation and scale using a fairly large area that is fairly close to where you are going to put the clock like maybe the black door frame's edges, rename the layer "stabilized" then do the composite, add a null, apply this animation preset to the null and parent both the stabilized layer and the composited clock to the null to put the motion back in the clip and match the composite layer to the camera motion. If the shot was different I'd use a different technique.

             

            The preset adds this expression to the null's position:

            thisComp.layer("stabilized").transform.anchorPoint

            This is the expression applied to the null's scale property:

            x = value[0];

            y = value[1];

            tx = thisComp.layer("stabilized").transform.scale[0];

            ty = thisComp.layer("stabilized").transform.scale[1];

            nx = x/tx*x;

            ny = y/ty*y;

            [nx, ny]

            It looks complicated but it's really simple the original scale of the null is divided by the scale value of the stabilized layer then multiplied by the scale. The expression is complicated because you cannot divide arrays by arrays.

             

            This is the expression for rotation:

            - thisComp.layer("stabilized").rotation

            This just reverses the rotation value.

             

            When you parent the stabilized layer and the composite to the null the motion is added to the composite layer (clock) and the stabilized shot has the stabilization removed. This leaves all keyframes in place so you can make any corrections you need to make. BTW, you'll probably have to do some hand correcting when you track the shot because the focus shifts. It's going to take a lot of hand work but I was able to get an acceptable track from your footage and drop in a clock in about 15 minutes. I picked two points, one on each side of the actor, stabilized scale and rotation, held down the Alt/Option key to move the tracking areas as they became obscured, then stabilized the shot, added the clock to the first frame, while the shot was still stabilized animated a little distortion on the clock because of the perspective shifts caused by the moving camera, then added a null, animated some lens blur for the clock, enabled motion blur for the clock layer. To complete the scene it would be necessary to do a little roto where the actor passes in front of the clock by animating a mask. You could either use a duplicate of your stabilized footage or animate a mask on the clock. That's about it. The composition looks like this:

            Screen Shot 2015-04-08 at 7.05.00 AM.png

            Just a little planning and some better camera work would have made this scene a lot easier. BTW Camera Tracking for this shot will not work because the actor is taking up so much of the frame. A program like Syntheyes could possibly track the shot, but as Mylenium said, better preproduction planning would save you a bunch of time in post and give you a better product.

            • 3. Re: How best to motion track blurry footage
              chrisj71 Level 1

              Awesome!  Thanks for the work up on this.  I'll give this a try. 

               

              I was brought in during post and was not part of the pre-production.  The hand-held shakiness is a desired effect by the director.

              • 4. Re: How best to motion track blurry footage
                chrisj71 Level 1

                Thanks for taking a look.

                 

                I was brought in during post and was not part of the pre-production.  The hand-held shakiness is a desired effect by the director.

                • 5. Re: How best to motion track blurry footage
                  Rick Gerard Adobe Community Professional & MVP

                  chrisj71 wrote:

                  ....The hand-held shakiness is a desired effect by the director.

                  The hand-held look is not the problem, the problem is that the shot was made without any consideration for post produnction and this must be communicated to the director so the same mistake is not made in the future and so you have some more room in the budget for this shot. Given the lack of planning I would double, maybe triple my bid for this shot.

                   

                  I gave you the technique and tools to successfuly complete the shot. It's just going to take some time to clean up the tracking by hand and do the roto, then match the focus changes. The technique I described will automatically match the motion blur but that is the only thing in this project that isn't going to require a bunch of hand work. If you blow away the director with an amazing composite without understanding and explaining exactly how to get this shot so the composite can be efficiently produced you are not doing the director or yourself any favors.

                  • 6. Re: How best to motion track blurry footage
                    chrisj71 Level 1

                    I appreciate the information you provided 100% and agree on every detail. 

                     

                    What i was trying to say is that I was not involved in the production.  The director approached me while she was in post to ask if the clock could be added.  The shaky cam was an artistic choice made without regard for VFX.  I have communicated that in the future if she wants more work to consult me in advance so I can set her and anyone doing VFX up for success.

                    • 7. Re: How best to motion track blurry footage
                      Rick Gerard Adobe Community Professional & MVP

                      I successfully added the a clock to the shot in about 15 minutes. It would take about an hour to perfect the track so that it was didn't shift at all and fix any perspective changes caused by the camera moving from left to right, then probably another half hour for roto work put the clock behind the actor, then maybe another half hour to get the focus to track perfectly, then 10 or 15 minutes for color grading and blending the edges. It can be done, but if it had been properly planned instead of an couple of hours in post it would have been a half hour.