The controls for positioning the each corner of the corner pin are right there when the Corner Pin tab is selected. The movement between frames of each corner of the corner pin, for each frame, is based on the sum of the tracker position movement and the change in the Reference Time Position. Change either and the position of the corner point changes.
Tracker move + RTP move = Point move.
So to get the change in any corner point position due to the tracker with regard to the reference frame position, I can make the point move 0 by moving the corner point back to where it was on the reference frame. The value in the RTP offset must equal the inverse of the Tracker move value with regard to the reference frame..
Here is a simple example in case that explanation is not great.
https://drive.google.com/file/d/1L_jjJ7 ... sp=sharingCorner Pin 1 is just a simple example, in Corner Pin 2 I have set the corner points in the reference frame to the corners of the rastor. At frames 325,350 and 400 I have repositioned the corners back to the corner of the rastor. The numbers in the offsets at these frames, represent the difference in position, from the reference frame, of all four points, at each of these frames. So to take frame 325 as an example, bottom left began at x0y0 at the reference frame, in order to return that point to the corner of the rastor, I had to offset it x 0.012705 y 0.127814. So the track has moved the corner x -0.012705 y -0.127814 in relation to the reference frame. That's the only way I can see of getting the data you want but it's not very practical.
You will also see in the spline graph that the offsets can be manipulated to some extent both the handles and from side to side in time. This will give you the control of the corner pin you want but as I mentioned, ideally the offsets would be on the track tab. Maybe that is difficult to do or maybe in future.