Perhaps you are thinking something along the lines of this rough test using a polygon mask.
Keep this in mind: To clear a mask in VideoPad, select the mask and click the "Clear Mask" icon, which is located to the right of the mask icon on the toolbar. After you clear the mask, any effects you add will apply to the entire video clip instead of just the masked region. This action resets your masking so effects are no longer restricted to a selected area and restores full-frame editing.
Girl.mp4
For a short while, the project is here, to dissect for ideas. You can do better.🙂 Download, unzip, run the VPJ.