crop and pan (transform)

[2dachopa]

Firstly, I love how light and responsive avidemux is and am eager to learn what its running under the hood. 

I tried aviremux in response to shotcut (22.12.21) failing to perform a particular task. In fairness, later versions rectified this, but I am using Win7 on a laptop, and that was the last usable version for Win7.

The task is to re-encode a 1920x1024 video down to 404x720 rectangle (or thereabouts) for mobile screens while panning (transforming) that rectangle to follow the action. I don't want to scale the video down, but to crop the video to the new dimensions. In shotcut, this required keyframes.

I understand aviredux does not do keyframes, but it will crop to the smaller dimension. Is it possible to add keyframe capability... without rewriting the framework?

I noticed there is a "scripting shell" and "custom" option in the toolbar. Have not read up on it yet. Perhaps there is a solution there? Since I've plotted keyframes in Shotcut, I can note their timestamps and add them to a textfile and/or hardcode the rectangular X/Y position into a script. I can also create a programmable function to ease-in/out of keyframes so panning (moving the rectangle) is smooth.

Thanks!