How can I separate scale dimensions?

[Chad5CE4]

I'm currently manually stabilizing a shot in the graph editor.  The image has a lot of "jello" (vertical squeezing) from rolling shutter.  I've tracked two points (one towards the top of frame and one towards the bottom) to gather up scale data between those two points, and then I'm using the expression [1/value[0], 1/value[1]]*10000 to lock those two points at a distance from each other, to effectively counteract the vertical squeezing.  The problem with this is that I only need it to affect the vertical scale and not the horizontal (X axis).  This would be easy to control, if I could simply separate the scale dimensions and globally set all my horizonal scale to 100% - but I can't seem to do so without also affecting the vertical scale.  I CAN manually enter in 100% for each keyframe after un-checking the "maintain aspect" box, but this is a pain as there are over 1000 frames.

Is there a quick way to select & edit the values of, say, only the horizontal keyframes at once?

[Rick Gerard]

Vertical squeezing does not normally come from rolling-shutter unless the video is framed in portrait mode instead of landscape. Rolling-shutter causes the vertical lines in a normal shot to bend as the camera pans or the action moves across the screen. That said I'm not sure what you mean when you say you are trying to manually stabilize a shot and you are motion tracking two points that are basically offset vertically. This sounds more like a shot that you would want to warp stabilize. Please describe the shot in detail. Tell us what is going on in the scene and how the camera moves, or better yet, show us a sample.

You cannot separate dimensions for anything but Layer/Transform/Position. The graph editor is the last tool I would use to try and stabilize a shot.

If you want to maintain the same distance between two features that you are tracking and you don't want the X scale of the layer to change you should set up your tracking points so they are separated vertically, select Stabilize, Scale, and probably Rotation, then run the motion tracker and apply it to the footage. All you have to do to the footage layer is then add a very simple expression to scale that sets the X scale to 100 and reads the value of the Y scale. The expression looks like this:

[100, value[1]];

The project would look like this. I'm showing you the Layer Panel and all the modified properties of the layer after the tracker has run. The height of the doorway never changes.

Fixing the position change with a couple of keyframes gives you a very strange visual effect. Some basic color correction to the Log footage and you get this: