Easily convert music via the Linux commandline by using ffmpeg
OPUS is a good format for storing audio. I recommend using it. .Convert all .flac files to .opus
for i in *.flac; do ffmpeg -i "$i" -c:a opus -b:a 256k "$\{i%.*}.opus" ''' done
From your OPUS you can convert to aac or mp3.. Or anything else
To convert OPUS to aac
for i in *.opus; do ''' ffmpeg -i "$i" -c:a libvo_aacenc -b:a 192k "$\{i%.*}.aac" ''' done
Opus to mp3``
for i in *.opus; do ''' ffmpeg -i "$i" -c:a libmp3lame -b:a 192k "$\{i%.*}.mp3" ''' done