Hasta La Motion!

So I was having some issues tracking a shot, and smoothcam (with a decent mask) gave me a good result. I was going to use this to matchmove an element, but due to smoothcam not working with infinite workspace, and some clipping issues, I needed to link the motion to a move2d via expressions. This would be easy as pie if smoothcam would output actual position values. Instead, it does a sort of "change in value over this frame" translation value.

So if it moved one pixel in X, the value is 1, rather than going from say, 640 to 641.

In the graph I wind up with a centered squigly line, rather than a squiggly slope like I needed.

So i ask you all, how can I (in expressions) convert this "change per frame" translation data into an actual position for my element?

I eventually hand animated it, which worked fine for this shot, but I need to know this for a later date.

And I probably couldn’t get smoothcam to work with infinite workspace via user-error, but still I want to know how to do this conversion.

Thanks all!