ffmpeg screen casting

ffcast

#!/bin/bash

function at_exit {
    sudo rmmod v4l2loopback 2> /dev/null
}

function usage {
    echo "Usage: $0 [<screen>]"
}

trap at_exit EXIT

video_nr=$(( $(ls /dev/video* | sort -nr | head -n1 | sed -e 's#/dev/video##') + 1 ))

sudo modprobe v4l2loopback video_nr=$video_nr 'card_label=screenShare' exclusive_caps=1

SCREEN=${1:-0}

monitor=$(xrandr --listmonitors | awk -e '/^\s+'$SCREEN':/ { print $3 }')
screen_w=$(echo $monitor | awk -Fx '{ print $1 }' | awk -F/ '{ print $1 }')
screen_h=$(echo $monitor | awk -Fx '{ print $2 }' | awk -F/ '{ print $1 }')
screen_x=$(echo $monitor | awk -F+ '{ print $2 }')
screen_y=$(echo $monitor | awk -F+ '{ print $3 }')

ffmpeg -loglevel error -f x11grab -r 20 -s ${screen_w}x${screen_h} -i :0.0+${screen_x},${screen_y} -vcodec rawvideo -pix_fmt yuv420p -threads 0 -f v4l2 /dev/video${video_nr}

exit 0