Zoom-crop.sh

#!/bin/sh
# Crops output of camera to zoom in for Zoom sessions

# apt install v4l2loopback-dkms v4l2-ctl ffmpeg

# Check if v4l2loopback not running
if ! v4l2-ctl -D -d 5 >/dev/null 2>&1; then
   echo "Create virtual video device (requires sudo)"
   sudo modprobe v4l2loopback video_nr=5 card_label="Loopback video"
fi

# Camera resolution is 1920x1080

echo "Activating loopback video device - press <q> to exit"
# ffmpeg -hide_banner -loglevel error -s 1920x1080 -i /dev/video0 -f v4l2 -pix_fmt yuv420p -filter:v "crop=1280:720" /dev/video5

ffmpeg -hide_banner \
   -loglevel error \
   -s 1920x1080 \
   -i /dev/video0 \
   -f v4l2 \
   -pix_fmt yuv420p \
   -vf "crop=1280:720, lenscorrection=k1=-0.1:k2=-0, eq=brightness=-0.1" \
   /dev/video5

echo "Loopback video device feed closed"
kill -9 $PPID