This concerns special characters common in non-english languages (for example norwegian, german, spanish, polish), see help request https://sourceforge.net/projects/ripperx/forums/forum/3070/topic/2696468/
This possibly also concerns kanji characters, see bug 3430169 (Does not handle kanji in song titles)
https://sourceforge.net/tracker/?func=detail&aid=3430169&group_id=1068&atid=101068