added script...

normalizesound.sh

@@ -0,0 +1,31 @@
+#!/bin/bash
+
+
+#ffmpeg -i file.mp3 -af "volumedetect" -vn -sn -dn -f null /dev/null 2>&1 | grep "max_volume" | tr -s ' ' '\n' | tail -n 2 | head -n 1
+
+for i in  *.m4a
+do
+
+echo "$i"
+dbvalue=$(ffmpeg -i "$i" -af "volumedetect" -vn -sn -dn -f null /dev/null 2>&1 | grep "max_volume" | tr -s ' ' '\n' | tail -n 2 | head -n 1)
+
+echo $dbvalue
+
+if [ "$dbvalue" == "0.0" ]
+then
+echo "nothing to change..."
+
+else 
+
+dbvaluechanged=$(echo $dbvalue | cut -c 2-)
+
+echo 'change '$dbvaluechanged'db'
+
+#ffmpeg -i "$i" -af 'volume='$dbvaluechanged'dB' "new_$i" 2> /dev/null
+#rm "$i"
+#mv "new_$i" "$i"
+#echo "replaced old file..."
+
+
+fi
+done