Gah - a solution with more questions. – EntropicLqd
From Unreal Wiki, The Unreal Engine Documentation Site
OGG is an open-source sound format similar to but proven to be better than MP3. More precisely, Wikipedia:Ogg is a project to provide all sorts of bitstream codecs, but when people say Ogg they usually mean the sound file format Ogg Vorbis (see Wikipedia:Vorbis for all the technical details).