Transcode FLAC files to AAC. Grabs all FLAC files in the given directory, transcodes to AAC, then makes some attempt to copy tags and, if folder.jpg is found, to embed album art.

flake.sh

#! /bin/sh

# Transcode FLAC files to AAC. Grabs all FLAC files in the given directory,
# transcodes to AAC, then makes some attempt to copy tags and, if folder.jpg is
# found, to embed album art.

AAC_FLAGS="-q 0.5"

FLAC_TAGS="TITLE ARTIST ALBUM GENRE TRACKNUMBER DATE"
AAC_TAGS="title artist album genre track year"

TAGCOUNT=`echo "$FLAC_TAGS" | grep -o ' ' | wc -l`
TAGCOUNT=`expr $TAGCOUNT + 1`

if [ $# -lt 2 ]
then
    echo "Usage: $0 infolder outfolder" 1>&2
    exit 1
fi

if [ ! -d "$1" -o ! -r "$1" ]
then
    echo "$1 does not exist or is not readable." 1>&2
    exit 2
fi

if [ ! -d "$2" -o ! -w "$2" ]
then
    echo "$2 does not exist or is not writable." 1>&2
    exit 3
fi

for file in "$1"/*.flac
do
    if ! file "$file" | grep -q "FLAC audio bitstream data"
    then
        echo "$file is not valid FLAC audio." 1>&2
        continue
    fi

    outfile="$2"/`echo "$file" | sed -e 's/.*\/\(.*\).flac/\1/'`.m4a

    flac -dc "$file" | \
        neroAacEnc $AAC_FLAGS -if - -of "$outfile" 2>/dev/null

    for i in `seq 1 $TAGCOUNT`
    do
        flac_tag=`echo "$FLAC_TAGS" | cut -d ' ' -f $i`
        aac_tag=`echo "$AAC_TAGS" | cut -d ' ' -f $i`

        val=`metaflac --show-tag=$flac_tag "$file" | sed -e 's/.*=//'`

        neroAacTag "$outfile" -meta:"$aac_tag"="$val" 2>/dev/null
    done

    if [ -r "$1"/folder.jpg ]
    then
        neroAacTag "$outfile" -add-cover:front:"$1"/folder.jpg 2>/dev/null
    fi
done