lame

http://lame.sourceforge.net/about.html

Lame (standing for lame aint mp3 encoder) lets you encode your .wav etc into .mp3. You can use it with the comand below in a consol but are much more likely to use it without noticing in many of the graphical based ripping and encoding programs such as grip.

$ lame -h input.wav output.mp3

  -h encodes in high quality

  input.wav is the file you want to encode

  output.mp3 is the resulting file that lame will make for you 

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