Take a random screengrab from a movie file and set it as your background

wallpaper.sh

#!/usr/bin/env bash

if [ ! -f "$1" ]; then
    echo "No such file"
    ¦ exit 1
fi
suf="${1##*.}"
if [ "$suf" != "mp4" ] && [ "$suf" != "mkv" ] && [ "$suf" != "avi" ] && [ "$suf" != "mov" ] && [ "$suf" != "gif" ] && [ "$suf" != "flv" ]; then
    echo "Input needs to be a video"
    exit 1
fi

location="/home/fergalm/Pictures/Wallpapers/frame.png"
duration=$(ffmpeg -i "$1" 2>&1 | grep Duration | awk '{print $2}' | tr -d ,)
seconds=$(echo "$duration" | awk -F: '{ print ($1 * 3600) + ($2 * 60) + $3 }')
seconds=${seconds%.*}
if [ "$seconds" -le 0 ]; then
    echo "Error setting wallpaper"
    exit 1
fi
randpoint=$((1 + RANDOM % "$seconds"))
ffmpeg -ss "$randpoint" -i "$1" -vframes 1 "$location" -y >>/dev/null 2>&1

gsettings set org.gnome.desktop.background picture-uri "file://$location"
xfconf-query --channel xfce4-desktop --property /backdrop/screen0/monitor0/image-path --set $location
xfconf-query --channel xfce4-desktop --property /backdrop/screen0/monitor1/image-path --set $location