Curlew is an easy to use, Free and Open-Source Multimedia converter for Linux.
Pretvarač zvuka
soundKonverter is a frontend to various audio converters.
DeaDBeeF
DeaDBeeF lets you play variety of audio formats, convert between them, customize the UI almost any way you want, and use many additional plugins which can extend it even more.
cijan
Ciano je multimedijski pretvarač za sve formate koji su vam potrebni.