I found a tool with the awfull name “SUPER ©”. The interface is bad, the website is bad, my antivirus tolds me that the tool create virusses and the tool cannot start without admin rights. If you can ignore al of this crap, SUPER © is the freeware tool to convert almost every media file.
You can download the file here: http://www.erightsoft.com/S6Kg1.html