Program Listing – m4atomp3

#!/bin/bash

# convert .m4a to .mp3 recursively

# be sure to run this only on a backup

# copy of your music

#

# cd to the directory which is above

# the artist names

#

# Author: Dan Srebnick

# All rights retained

# Free to use for personal use

######################################

shopt -s nullglob

for ARTIST in *; do

  if [ -d "$ARTIST" ] ; then

    cd "$ARTIST"

    for ALBUM in *; do

      if [ -d "$ALBUM" ] ; then

        cd "$ALBUM"

        DISC1=0; DISC2=0; MULTI=0  

        DISC1=`find . -name "1-[0-9][0-9]*.m4a" | wc -l`

      DISC2=`find . -name "2-[0-9][0-9]*.m4a" | wc -l`

      if [ $DISC1 -ge 1 ]; then

          DISC1=1

        fi

      if [ $DISC2 -ge 1 ]; then

          DISC2=1

        fi

      let MULTI=$DISC1+$DISC2

      echo "Multi is $MULTI"

        for i in *.m4a; do

        TMPFILE="/tmp/ffmpeg$RANDOM.txt"

        ffmpeg -i "$i" 2>$TMPFILE

        line="`grep ' artist ' $TMPFILE`"

        if [ -n "$line" ] ; then

          ARTIST="`echo $line | awk -F':' '{print $2}' | cut -c2-`"

        fi

        line="`grep ' track ' $TMPFILE`"

        if [ -n "$line" ] ; then

            TRACK="`echo $line  | cut -d ":" -f2 | cut -d "/" -f1 | tr -d " "`"

        fi

        line="`grep ' disc ' $TMPFILE`"

        if [ -n "$line" ] ; then

          DISC="`echo $line | cut -d ":" -f2 | cut -d "/" -f1 | tr -d " "`"

        fi

        line="`grep ' title ' $TMPFILE`"

        if [ -n "$line" ] ; then

          TITLE="`echo $line | awk -F':' '{print $2}' | cut -c2-`"

        fi

        line="`grep ' album_artist ' $TMPFILE`"

        if [ -n "$line" ] ; then

          ALBUM_ARTIST="`echo $line | awk -F':' '{print $2}' | cut -c2-`"

        fi

         

        echo "Artist: $ARTIST"

        echo "AlbArt: $ALBUM_ARTIST"

        echo "  Disc: $DISC"

        echo " Track: $TRACK"

        echo " Title: $TITLE"

        echo

        rm "$TMPFILE"

        if [ -z "$ARTIST" ] ; then

          ARTIST="$ALBUM_ARTIST"

        fi

        if [ $MULTI -eq 2 ]; then

          if [ $DISC -eq 2 ]; then

            let TRACK=$TRACK+25

          elif [ $DISC -eq 3 ]; then

            let TRACK=$TRACK+50

          elif [ $DISC -eq  4 ]; then

            let TRACK=$TRACK+75

          fi

        fi

        if [ $TRACK -lt 10 ]; then

           TRACK="0$TRACK"

        fi

        TITLE="`echo $i | cut -d " " -f2- | rev | cut -c 5- | rev`"

          MP3SONG="$TRACK-$ARTIST - $TITLE.mp3"

        echo -e "$MP3SONG\n"

          ffmpeg -i "$i" -vsync 2 -acodec libmp3lame -ac 2 -aq 0 -ar 44100 -write_id3v1 1 "$MP3SONG"

        done

        cd ..

      fi

    done

    cd ..

  fi

done