playvideo_omx.sh

#!/bin/sh

# get rid of the cursor so we don't see it when videos are running
setterm -cursor off

# set here the path to the directory containing your videos
VIDEOPATH="/USB_video"

# you can normally leave this alone
SERVICE="omxplayer"

# now for our infinite loop!
while true; do
        if ps ax | grep -v grep | grep $SERVICE > /dev/null
        then
        sleep 1;
else
for entry in $(find /USB_video/ -iname '*.mp4' | shuf -n 1);
do
                clear
                omxplayer -o both --win "-40 -40 800 600" $entry > /dev/null
        done
fi
done