ffmpeg_flac2fdk_aac.sh

#
# Note: For libfdk_aac requires ffmpeg built with `--enable-libfdk-aac' and not `--enable-gpl',
#       On Debian-based distros the package from www.deb-multimedia.org repos compiles it as such.
# TODO: probably easier in something python based like this https://github.com/Eloston/misc-programs/tree/master/flac_to_ogg
ff_flac2aac() (
    { [ -n "${ZSH_VERSION-}" ] && emulate -L zsh -o nullglob; }; local f i of 2>/dev/null
    if [ $# != 0 ]; then
        if ([ -d "${1}" ] && [ $# -eq 1 ]); then { cd "${1}" || return; }
        elif ([ -f "$1" ] && [ $# -eq 1 ]); then { f="${1}"; }
        elif ([ $# -gt 1 ]);                then { for i in "$@";do f+=("${i}");done; }
        fi
    fi
    if [ -n "$f" ]
    then    for i in "${f[@]}";do of="${i/.flac/.m4a}"; ffmpeg -i "${i}" -vn -c:a libfdk_aac -b:a 256k -f mp4 -y "${of}";done # AAC LC
    else    for i in *.flac;do    of="${i/.flac/.m4a}"; ffmpeg -i "${i}" -vn -c:a libfdk_aac -b:a 256k -f mp4 -y "${of}";done # AAC LC
    fi                          # Note: CBR valid bitrates: 6k,24k,32k,40k,48k,56k,64k,80k,96k,112k,128k,160k,192k,256k,320k,448k
                                # of="${i/.flac/.m4a}"; ffmpeg -i "${i}" -vn -c:a libfdk_aac -profile:a aac_he -b:a 192k -f mp4 -y "${of}";done     # AAC HE v1
                                # of="${i/.flac/.m4a}"; ffmpeg -i "${i}" -vn -c:a libfdk_aac -profile:a aac_he_v2 -b:a 128k -f mp4 -y "${of}";done  # AAC HE v2
)

ff_flac2aac "$@"