Mp3

convert mp4a to mp3

ffmpeg -i inputfile.m4a -acodec libmp3lame -ab 93k outputfile.mp3

record mic on linux and convert it to mp3 with noise filter

arecord --device="hw:0,0" --format=S16_LE -c 2 rec.wav
ffmpeg -i rec.wav -af "highpass=200,lowpass=3000,afftdn" -ss 00:01 -to 00:60 -acodec mp3 rec.mp3
ffplay rec.mp3