How to keep a moving object stationery on screen, BG moves to compensate

If I have a shot of a dog running, how can I keep that dog running in the right third of the screen as if on a treadmill? As if it was shot with a camera that followed alongside?

Another example might be a horse race where the horse runs but stays in the same spot (the right third of the screen).

I'm assuming the answer has something to do with motion tracking... but I'm pulling my hair out on this one.


  • Holy smokes! That is so cool! 

    Thanks for the vid postings. With "stabilization" and the aid of a mask, I got exactly what I wanted, (me - or anything, really - running in place).

    Thanks again!

  • When I add a mask to the composite layer:

    • The mask moves if I add it to the stabilized layer - so that doesn't seem the way to go...
    • And if I try adding a new "plane" layer and adding a mask to that, that layer has a background. No amount of "inverted" masks or changes to the blend mode will make this background go away.

    What I finally ended up doing was to create a secondary composite shot from the "stabilized" composite shot and creating a mask over that. I then dragged that secondary composite shot onto the editor timeline. This seems like a step too far - is this the way to do it - or is there a simpler way?

  • edited October 2017

    I found a slightly simpler solution:

    It took me awhile to figure out the instructions found there - allow me to paraphrase and slightly adapt, should anyone else be looking to do something similar and find themselves stumped:

    1. Once you've got your "stabilized shot" stabilized (the object stays in one spot, the rest of the background moves to keep it stationery) right click the name/layer containing the stabilized footage (it's numbered and has an eyeball next to it) and select "make composite shot." 
    2. This will open a small dialogue box (and this is the part that was missing for me before). Under "Take composite shot properties from" I left the default "Selected layer" selected - but under the next option, "Masks, effects and transform properties," I had to select "Move with layer." (Not making that selection is what caused this to work incorrectly in prior attempts.)
    3. You will automatically move/flip to the newly-created composite shot, but you want to...
    4. Click back to your original stabilized shot, the one that you made into a composite shot.
    5. Add your mask to the stabilized layer. Done.

    Thanks much to Axel Wilkinson and Triem23 for the help!

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