There will situations, where you will want to convert MP3 files to OGG Vorbis files, some of these situations are when you are making a podcast show, you may record your podcasts as MP3 files, and then you will need to convert it to OGG Vorbis files, for your Linux listeners.
That is my case, as I am starting with a Podcast show. The command you need to perform this task, is
oggenc, and the packages you need to install are
How to convert MP3 to OGG Vorbis file
To convert MP3 to OGG vorbis just run this command
mpg321 [input-file.mp3] -w - | oggenc raw -o [output-file.ogg]
That is it.