In order to convert flac to mp3 you need to install ffmpeg in your computer.
As a root:
1. apt-get install ffmpeg
2. apt-get install lame
3. apt-get install libavcodec-extra-53
Then run command as follow:
ffmpeg -i audio_souce.flac -ab 256k audio_output.mp3
Where ab is bitrate in kb/s
Enjoy
