Screen cast with ffmpeg / xwininfo.

ffscreencast.zsh

#!/usr/bin/zsh

SAVE_DIR=/home/foo/Videos/

even_round() {
  perl -n -e '/(\d+)(.)(\d+)/; print( $1 % 2 == 0 ? $1 : $1 - 1 ); print $2; print( $3 % 2 == 0 ? $3 : $3 - 1 )' <<< "$1"
}

mic_arg() {
  if (( $mic == 1 ))
  then
    print -- "-f alsa -i pulse -acodec aac"
  fi
}


integer wmode=0
typeset -g mic=0

for i in "$@"
do
  #Window mode ( -w option. )
  if [[ $i == "-w" ]]
  then
    integer wmode=1
  fi
  
  #Pulse mic
  if [[ $i == "-m" ]]
  then
    typeset -g mic=1
  fi
done  

if (( wmode == 1 ))
then
  xwininfo=$(xwininfo -frame)
  geo=$(perl -n -e '/geometry (\d+x\d+)/; print $1;' <<< "$xwininfo")
  corn=$(perl -n -e  '/Corners:\s+\+(\d+)\+(\d+)/ && print $1 . "," . $2;' <<< "$xwininfo")
  
  ffmpeg -show_region 1 -f x11grab -video_size $(even_round $geo) -i "$DISPLAY+$(even_round $corn)" ${=$(mic_arg)} -vcodec libx264 -preset ultrafast -qp 0 "$SAVE_DIR/$(date +"%y%m%d%H%M%S")".mp4
  else
  geo=$(xwininfo -root | perl -n -e '/geometry (\d+x\d+)/ && print $1;')
  ffmpeg -f x11grab -video_size $(even_round $geo) -i "$DISPLAY" ${=$(mic_arg)} -vcodec libx264 -preset ultrafast -qp 0 "$SAVE_DIR/$(date +"%y%m%d%H%M%S")".mp4
fi