ogg2mp3 runs from the command line. To convert an OGG to MP3:
% ogg2mp3 file.ogg
To convert a MP3 to OGG:
% ogg2mp3 -r file.mp3
For more options:
% ogg2mp3 -h
Requirements:
ogg2mp3 requires three custom auxiliary modules I have made. More precisely, you need the modules, DataManipulation.py, FileManipulation.py and System.py. You can download them here.