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Synchronizing track data for two similar clips with AE
Hi!
I’m having a tiny bit of a struggle. I’ve got two aerial video clips that are similar (both are recording of an orbiting flight with a monument in center, each is recorded in different stages of its construction process), and would like to overlay one over other and mask-in the elements of the “after” clip over the “before” clip. The problem is though, that they do differ a little bit and I find it tricky to avoid the “floating” movement of the masked elements over the clip that is below. I think that there should be a way to somehow synchronize these two clips by setting the same track points for both of them, so that AE (or MochaAE) would “know” that e.g. Track Point no.1 of the clip below represents the Track Point no.1 on the clip above, and by doing the same stuff with, let’s say, 3 different pairs of points, would take care of the floating by “pinning” the paired points and take care of the proper movement of the masks with perspective, and other automatic transformations.I’ve been dealing with such “stabilization” issues before, but only when the second clip was artificial/3D animation, which allowed me to tinker with the shot. Now, in this current case, I cannot reshoot any of the clips and need to find a way to deal with all that somehow. Could somebody give me a hint on how to do that properly, without adjusting the clips manually frame-by-frame?
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1 Reply
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Since your shots have 3D camera moves, there is no quick way to synchronize them using 2D transforms. If they are super similar as far as height and position goes, you can try doing a retime on one clip so that the orbit speed matches the other. Make sure you’re on pixel motion for your frame blending if you are slowing the clip down at all. Use timewarp if you need to slow it a bunch. Then use a mesh warp to bend it a little as needed.
You might also try warp stabilizing both clips first, using the ground (not the statue). Retime the clips to match orbit speeds as much as possible. Then tweak your transforms and mesh warp to dial it in.
Another option, and probably the best one, is to use photogrammetry techniques to create a 3D version of both shots. Then align them and re-create the camera move.
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