Spacial Motion Based Time Warp

[josh3light]

Imagineer's Mokey can track the plate and automatically give you a stabilized smooth version of the camera movement.

[Aruna]

Uhm.. Won't this speed up or slow down the actors or action that was filmed (if you filmed actors)?

[josh3light]

that is a good question. I couldn't tell with the footage it was used on, as it was a zoom in of a person lying still. But as I understand it, the position, rotation, and scale of the footage is interpolated to give a smooth result without disturbing the underlying movement, as long as there is something static in the frame to track.

[backwheelbates]

Ya that's totally right Aruna! But the footage Im trying to retime is all environments, so Im not worried about actors being retimed. I was thinking there must be a way to track a point or 2 throughout the entire shot, and then timewarp the shot in such a way that it would smooth the velocity of the tracked reference points. I know the concept is there, but Im not really sure how to implement it in, say, after effects, shake or fusion.

[pgraham]

In shake, use a stabilize node to lock down the camera motion, then you can use a move2d to move it however you want. If you copy the keys from the stabilize into the move2d and use the smooth function in the curve editor, you can theoretically get a smoother version of the original camera motion.

As far as time warping, here's a little analysis...
The track path is a function of time, which means you tell it what time you want (what frame you're looking at) and the function tells you the position of the footage. You would need the inverse of that function, one that you give a position value and the function would tell you what time the footage gets to that position. Then you could time warp to each frame on a straight line and you would get the smooth motion you want. Unfortunately there's no automatic way to inverse a track path because there are some mathematical problems (if the tracker visits the same position at 2 different times, then the inverse is undefined at that position).

If you can create a function that takes a position and gives you a time value, then yes you can time warp to stabilize the footage.

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