AffanIndo

# batch convert
for i in *.mp4; do ffmpeg -i "$i" "${i%.mp4}.webm"; done

# convert from one format to another
ffmpeg -i input.mp3 output.wav

# convert from one video format to another ("-qscale" value are 0-10, 0 is the best)
ffmpeg -i input.mp4 -qscale 0 output.webm

# convert video to audio (sometimes this one is better than the custom one below)