ffmpeg -i "song.wav" -ab 320k "song.mp3"

Batch:

for i in *.wav; do ffmpeg -i "$i" -ab 320k "${i%.*}.mp3"; done

for i in *.wav; do ffmpeg -i "$i" -f mp3 "${i%}.mp3"; done

Mono to stereo conversion:

ffmpeg -i test.wav -af "pan=stereo|c0=c0|c1=c0" out.wav

Strip Video:

ffmpeg -i input.wav -vn -ar 44100 -ac 2 -b:a 192k output.mp3

• -i - input file
• -vn - Disable video, to make sure no video (including album cover image) is included if the source would be a video file
• -ar - Set the audio sampling frequency. For output streams it is set by default to the frequency of the corresponding input stream. For input streams this option only makes sense for audio grabbing devices and raw demuxers and is mapped to the corresponding demuxer options.
• -ac - Set the number of audio channels. For output streams it is set by default to the number of input audio channels. For input streams this option only makes sense for audio grabbing devices and raw demuxers and is mapped to the corresponding demuxer options. So used here to make sure it is stereo (2 channels)
• -b:a - Converts the audio bitrate to be exact 192kbit per second

High quality

lame -h song.wav song.mp3

Fixed 128kbs stereo encoding

lame song.wav song.mp3

Fast and low quality

lame -f song.wav song.mp3

Encode at a bit rate of 112 kbs

lame -b 112 song.wav song.mp3

bladeenc song.wav song.mp3