Auto Face-Zoom AE Script

I’m looking for an ExtendScript (.jsx) or expression that removes the black bars that appear after I stabilise or face-track footage in After Effects. Right now I have to scrub through every clip, adjust Scale until the tracked face fills the frame, and repeat the same steps dozens of times. I want to press one button and have that whole routine happen automatically.

Core behaviour
• Read the existing face-tracking (or point tracking) data on the selected layer.
• Calculate the minimum scale required so the top and bottom black bars are completely hidden for the entire duration of the layer.
• Apply that scale, key-framed where necessary, so the face stays centred and fills the full 3:4 frame.
• Leave all other layer properties untouched.

Workflow details
– The script will be run from the File → Scripts menu (or a dockable panel if that’s quicker for you).
– I usually track with the built-in “Face Tracking – Detailed Features” effect, but the script should work as long as position keyframes exist on the layer.
– I edit usually in 1080x1440p comp; the calculation needs to respect the current comp size automatically.
– If no tracking data is detected, the script should alert me rather than failing silently.

Deliverable
1. A clean, well-commented .jsx file that I can drop into the Scripts folder.
2. Short read-me explaining installation and any UI elements you add.

Acceptance criteria
• On a test clip with face tracking, a single run of the script eliminates all black bars throughout the timeline.
• No extra scaling is applied when the footage already fills the frame.
• The project remains fully compatible with After Effects 2025+.

If you’ve built similar automation tools or have clever methods for scale calculations, I’d love to see a quick demo video or GIF along with your bid.