Linear movement with shape mask

I'm trying to keyframe a vertical movement for a shape mask but it is definitely "smoothing" out the beginning and end of the move, kind of like a bezier curve. The object that I'm masking is moving at a consistent speed but I am unable to track it with my mask because the mask's movement is not linear.

I know that a normal object transformation has the option to change this movement from "smooth" to "linear" but I don't see any way to adjust the movement characteristics of the shape mask.

Does anyone have any suggestions?

Let me be the first to say it, get TrackX. I don't think the built-in mask function let's you change the interpolation type.

FCPX.guru wrote: Let me be the first to say it, get TrackX.….

if he's the same person as here
discussions.apple.com/thread/8067975
(stalkingModeOff )
he has …

Trouble is a bit more complicated …

Yep, that was me. I've tried TrackX but the issue is that the object I'm tracking is not actually an object, but a rolling horizontal band of shaded footage. I'm trying to keyframe a color mask to correct it.

Manually keyframe in TrackX and you won't get the Ease In/Out issue.

The "track and lockdown" plugin for TrackX does not have "position" as a key-frameable parameter.

With TrackX you don't keyframe specific parameters, you keyframe the mask as a whole.

First, you MUST click the Key icon in the left hand HUD to turn on the keyframe abilities. A set of keyframes tools will then show in the lower portion of the Viewer pane.

Then you draw a mask shape on your first frame. The mask control points will be green, so grab one of the mask control points, nudge it slightly so they all turn yellow. Yellow means you just created a keyframe for the mask.

Then go to the frame that the movement should stop on, and manually drag the tracker (middle dot) and adjust individual mask control points as needed.