ffmpeg screen casting

ffcast

#!/bin/bash

if [[ $EUID -ne 0 ]]; then
  exec sudo $0 $*
  exit 0
fi

function at_exit {
  echo "Removing capture module..."
  rmmod v4l2loopback 2> /dev/null
}
trap at_exit EXIT

SCREEN=${1:-0}
MONITOR=$(xrandr --listmonitors | awk -e '/^\s+'$SCREEN':/ { print $3 }')
VIDEO_NR=$(( $(find /dev -name 'video*' | sort -nr | head -n1 | sed -e 's#/dev/video##') + 1 ))
DEVICE="/dev/video$VIDEO_NR"

echo "Loading module v4l2loopback over video $DEVICE..."
modprobe v4l2loopback video_nr=$VIDEO_NR 'card_label=screenCap' exclusive_caps=1

echo "Calculating capture geometry for monitor $MONITOR"
X=$(echo $MONITOR | awk -F+ '{ print $2 }')
Y=$(echo $MONITOR | awk -F+ '{ print $3 }')
WIDTH=$(echo $MONITOR | awk -Fx '{ print $1 }' | awk -F/ '{ print $1 }')
HEIGHT=$(echo $MONITOR | awk -Fx '{ print $2 }' | awk -F/ '{ print $1 }')

echo "Starting capture with geometry ${WIDTH}x${HEIGHT}@${X},${Y} to device $DEVICE..."
ffmpeg -loglevel error \
       -f x11grab \
       -r 30 \
       -s ${WIDTH}x${HEIGHT} \
       -i :0.0+${X},${Y} \
       -vcodec rawvideo \
       -pix_fmt yuv420p \
       -threads 0 \
       -f v4l2 $DEVICE