How to re-encode all WAV files in the current directory to OPUS
for i in *.wav ; do ffmpeg -i "${i}" -c:a libopus -vbr on -compression_level 10 "${i}.opus" ; done
for i in *.wav ; do ffmpeg -i "${i}" -c:a libopus -vbr on -compression_level 10 "${i}.opus" ; done