Small garage of one Ford in the big internet
sudo apt install v4l2loopback-dkms v4l2loopback-utils
sudo apt install libelf-dev
git clone https://github.com/umlaeute/v4l2loopback.git
cd v4l2loopback/
make
make install
depmod -a
sudo modprobe v4l2loopback video_nr=15 card_label="Fake webcam by v4l2loopback"
v4l2-ctl --list-devices
v4l2loopback-ctl set-fps 15 /dev/video15
ffmpeg -probesize 333M -video_size 1920x1080 -r 15 -threads 9 -f x11grab -i :0.0 -vf "scale=1280:720" -vcodec rawvideo -pix_fmt yuv420p -f v4l2 /dev/video15
rmmod v4l2loopback