if [[ -n $(pidof mpv) ]]; then
echo "loadfile "${targetVideo}" append-play" | socat - /tmp/mp_pipe
else
mpv "$targetVideo" input-ipc-server='/tmp/mp_pipe' &
fi
/usr/share/doc/mpv/input.conf
/home/bud/.config/mpv/mpv.conf
...
https://www.youtube.com/watch?v=P__GCB0R6Yg