Cast your screen to Facebook Live. Require `ffmpeg`, `xrandr`, `x11grab`, an audio driver (default to `pulse`)

facebook-screencast.sh

#!/bin/bash
if [[ $# -eq 0 ]] ; then
    echo "Usage: $0 <API_KEY> [AUDIO_SOURCE_NAME] [OUTPUT_WIDTH]";
    exit 0;
fi
AUDIO_SOURCE_NAME=${2:-pulse};
ALL_AUDIO=$(ffmpeg -sources alsa | while read -r line; do echo -e $(echo "$line" | cut -d ' ' -f1)" "; done);
AUDIO_SOURCE_FOUND=$(echo $ALL_AUDIO | grep $AUDIO_SOURCE_NAME);
if [ -z "${AUDIO_SOUCE_FOUND}" ]; then
    echo -e "Can't find audio source $AUDIO_SOURCE_NAME, please select 1 from:\n$ALL_AUDIO";
    exit 0;
fi
DIMENTIONS=$(xrandr --current | grep '*' | uniq | awk '{print $1}');
W=$(echo $DIMENTIONS | cut -d 'x' -f1);
H=$(echo $DIMENTIONS | cut -d 'x' -f2);
OUTPUT_WIDTH=${3:-$W};
ffmpeg \
-f alsa -ac 2 -i $AUDIO_SOURCE_NAME \
-f x11grab -framerate 24 -video_size $DIMENTIONS \
-i :0.0+0,0 -c:v libx264 -preset veryfast -b:v 3000k -maxrate 3000k -bufsize 3000k \
-vf "scale=$OUTPUT_WIDTH:-1,format=yuv420p" -g 60 -c:a aac -b:a 128k -ar 44100 \
-f flv "rtmps://live-api-s.facebook.com:443/rtmp/$1";