FFMPEG Convert Audio Quality

Convert mp3 to flac 16 bit dep and 48k:

ffmpeg -y -i "input.mp3" -c:a flac -sample_fmt s16 -ar 48000 high.flac

if want to convert bitrate, add more: -b:a 192k
Convert flac to mp3:

ffmpeg -i "high.flac" -ar 44100 tmp.mp3

FFMPEG Convert Audio Quality