6 Replies Latest reply on Apr 13, 2017 11:47 AM by kirkeric

    Tracking Camera of a Time Stretched Layer

    cooperepps Level 1

      Hey After Effects fam,


      Objective: Track a pre-comped animation (Pre Comp 1) to slow-mo, stabilized footage, all in After Effects.


      What I've done: Since the footage was bumpy and at 60fps, I slowed it down to 50% by using the Time Stretch function at 200. I then added Warp Stabilization to that footage to smooth it out even more. I pre-composed that to make Pre Comp 2.

      Back in the main composition, I used the 3d Tracker on Pre Comp 2, and made a camera and null out of some of the tracking points. All sounds normal right?


      Here's the issue: The animation (Pre Comp 1) that is now tracked to the camera, is moving as if it is tracked to the original footage. So it's not only moving twice as fast as it should, but it's jittery too since it's also ignoring the warp stabilization. In fact, I'd say it looks even worse. The average error of my track is .93, which isn't great, but at least below 1. The footage is sharp, from a Sony A7s. I double checked to make sure all the frame rates of the footage, animation, and compositions are all the same (29.97). Well, the footage is 60fps, but time stretched to 50% speed as I said before.


      So how do I reconcile the 3d Tracker with the 2 simple ways I altered the original footage?


      I could use the help as soon as possible.

      Thank you!!


      Here's the video:


        • 1. Re: Tracking Camera of a Time Stretched Layer
          Dave LaRonde Level 6

          Prerender the slo-mo & stabiliaed footage.  Use it for the camera track.

          • 2. Re: Tracking Camera of a Time Stretched Layer
            Rick Gerard Adobe Community Professional & MVP

            Your workflow is all fouled up.

            1. Warp stabilize the original footage to preserve as many original pixels as you can
            2. Render an image sequence (Preferable) or visually lossless digital intermediate from your original footage
            3. Do your time changes to your new DI
            4. Render another DI and add that to your project as the stabilized and slowed down footage
            5. Do your camera tracking on the second DI

            You may be able to get away with pre-comps and skipping the digital intermediate phase but it's very easy to get completely fouled up and unless the shot is very short the processing and rendering times are going to go through the roof. The number one goal in any workflow is to preserve as many original pixels and original frames as you can because everything you do starts to introduce errors.


            Slowing down then warp stabilizing will throw more errors  by far than warp stabilizing and then slowing down. If you have done anything to your footage including just moving it a couple of pixels down into the right you must pre-compose that shot or render it before you try to use any kind of tracking including camera tracking.


            I hope this helps.

            • 3. Re: Tracking Camera of a Time Stretched Layer
              cooperepps Level 1

              Thanks for the suggestions Rick and Dave!

              Unbelievably, I tried everything you suggested and I continue to get the same result.

              If you have a minute today, I'd love for you to take a look at my project. I know you, Rick, are especially good at digging through projects to uncover some silly mistakes.

              Here's a Google Drive folder with everything you need: Tracking for Adobe Forum - Google Drive

              "C0045" is the original 60fps footage; "C0045 2" was the footage stabilized in AE (no time alterations) and rendered out into an MOV file.

              Thanks for the help.

              • 4. Re: Tracking Camera of a Time Stretched Layer
                Kevin-Monahan Adobe Employee

                Have you solved this issue yet CooperEpps? Let us know so we can make more suggestions to help you out.



                • 5. Re: Tracking Camera of a Time Stretched Layer
                  cooperepps Level 1

                  Thanks for following up Kevin! No, this never got resolved. I settled with a different approach to the animation. But I would still love to figure out this problem if you're willing to look through the files I attached in my last response.

                  • 6. Re: Tracking Camera of a Time Stretched Layer
                    kirkeric Adobe Community Professional

                    I've seen the recommendations with Rich Gerard's being pretty descriptive but the thought had just occurred to me.  Have you considered doing all of the tracking before the stabilizing?  You say bumpy but not sure if it is so bumpy that it's untrackable.


                    My thought is, track it first, place your track objects or whatever you planned to do and then render out, bring back in to AE and THEN slow down and stabilize the footage.


                    Just a thought.