magick -size 1x1 canvas:teal out.png

vlc --loop out.png

# Keep screen active when reading videos from Firefox
function keep-screen-active {
  SUFFIX=.$FUNCNAME.png
  find /tmp -maxdepth 1 -type f -iname \*$SUFFIX -delete
  FILE=$(mktemp --suffix $SUFFIX)
  # This is a 1x1 px teal image.
  base64 --decode > $FILE <<-'EOF'
iVBORw0KGgoAAAANSUhEUgAAAAEAAAABAQMAAAAl21bKAAAAIGNIUk0AAHomAACAhAAA+gAAAIDo
AAB1MAAA6mAAADqYAAAXcJy6UTwAAAAGUExURQCAgP////lmmXQAAAABYktHRAH/Ai3eAAAAB3RJ
TUUH6gUdDBYzu8q/0wAAACV0RVh0ZGF0ZTpjcmVhdGUAMjAyNi0wNS0yOVQxMjoyMjo1MSswMDow
MAb9F8AAAAAldEVYdGRhdGU6bW9kaWZ5ADIwMjYtMDUtMjlUMTI6MjI6NTErMDA6MDB3oK98AAAA
KHRFWHRkYXRlOnRpbWVzdGFtcAAyMDI2LTA1LTI5VDEyOjIyOjUxKzAwOjAwILWOowAAAApJREFU
    CNdjYAAAAAIAAeIhvDMAAAAASUVORK5CYII=
    EOF
  vlc --loop $FILE
} 

# Keep screen active when reading videos from Firefox
function keep-screen-active {
  FILE=/tmp/$FUNCNAME.png
  magick -size 1x1 canvas:teal $FILE
  vlc --loop $FILE
}