mencoder is a package that allows you to convert files from one video format to another – there’s currently no GUI for it in Ubuntu. You can convert it to other types and add a whole bunch of options, but we’ll just focus on this. 
1) Get mencoder.
sudo apt-get install mencoder
2) Move the files to the directory.
3) cd (change directory) into the directory where the files are.
4) Convert:
mencoder -idx test.ogg -ovc lavc -oac mp3lame -o test.avi
*obediently says* hi