Code:
result=`ps -A | grep beep-media-player`
if [ "$result" == "" ]
then
exit
else
beep-media-player -s
fi
May not be the best, cleanest, or shortest code, but it should work. If beep-media-player isn't running the script will exit, if it is running it will execute beep-media-player -s.
If it doesn't work try running beep media player and typing ps -A and seeing what beep is called on the process list and matching it with the string after the grep call.