times=()
for f in *.mp3; do
    _t=$(ffmpeg -i "$f" 2>&1 | grep "Duration" | grep -o " [0-9:.]*, " | head -n1 | tr ',' ' ' | awk -F: '{ print ($1 * 3600) + ($2 * 60) + $3 }')
    times+=("$_t")
done
echo "${times[@]}" | sed 's/ /+/g' | bc