Convert all wav in directory to MP3 VBR 190-250 kbps:

for f in *.wav; do ffmpeg -i "$f" -acodec libmp3lame -vn -ar 44100 -ac 2 -q:a 1 "${f%.*}.mp3"; done

Convert wav to FLAC:

ffmpeg -i $SOURCE -q:a flac -compression_level 2 $OUT.flac

Insert ID3 Tag metadata with cover image to MP3:

for f in *.mp3; do ffmpeg -y -i "$f" -i cover.jpg -map 0:0 -map 1:0 -c copy -id3v2_version 3 -metadata:s:v title="Album cover" -metadata:s:v comment="Cover (front)" -metadata title="${f%.*}" -metadata album="Albumi" -metadata artist="Artists" -metadata genre="Audiobook" -metadata date="2008" -metadata publisher="Publisher" "output/${f%.*}.mp3"; done

Read all metadata from MP3 file:

 ffmpeg -i file.mp3 -f ffmetadata