Install MPV Script

1. Go to GitHub and find crop.lua file https://github.com/occivink/mpv-scripts/tree/master/scripts

2. Place lua file in directory %APPDATA%\Roaming\mpv\scripts\crop.lua

3. Create Input Config File %APPDATA%\mpv\input.conf

4. Add these line

# Start selecting a crop rectangle (hard crop filter)
c script-message-to crop start-crop hard

# Toggle apply/remove crop (after you’ve selected one)
C script-message-to crop toggle-crop hard

# Reset crop (remove last vf filter)
d vf del -1

5. Open MPV then hit Keybind mpv INPUT.mp4