diff --git a/convert.sh b/convert.sh
index c2609cb..d85b904 100755
--- a/convert.sh
+++ b/convert.sh
@@ -2,12 +2,12 @@
 
 if [ ${#} -ne "2" ] ; then
 	echo "Usage: ${0} <input file> <output file>"
-	return 1
+	exit 1
 fi
 
 TMPFILE="convert.tmp"
 
-ffmpeg -i ${1} -f u16be -ar 16k -ac 1 -acodec pcm_u16be ${TMPFILE}
-SIZE=$(( $(stat -c "%s" ${TMPFILE}) / 2 ))
-echo -ne "\0$(printf %o $(($SIZE % 256)) )\0$(printf %o $(( ($SIZE / 256) % 256)) )\0$(printf %o $(( ($SIZE / 256**2) % 256)) )\0$(printf %o $(( ($SIZE / 256**3) % 256)) )" | cat - ${TMPFILE} > ${2}
+ffmpeg -i "${1}" -f u16be -ar 16k -ac 1 -acodec pcm_u16be ${TMPFILE}
+SIZE=$(( $(stat -c "%s" ${TMPFILE} ) / 2 ))
+echo -ne "\0$(printf %o $(($SIZE % 256)) )\0$(printf %o $(( ($SIZE / 256) % 256)) )\0$(printf %o $(( ($SIZE / 256**2) % 256)) )\0$(printf %o $(( ($SIZE / 256**3) % 256)) )" | cat - ${TMPFILE} > "${2}"
 rm ${TMPFILE}