Hi!
Here is a patch that converts ogginfos from utf8 to the setup charset. It is tested with mp3 plugin 0.9.15 and mp3ng plugin 0.0.9a. The cache file /video/id3info.cache (or /video/id3info.dat for mp3ng) has to be removed.
http://toms-cafe.de/vdr/download/mp3-0.9.15-ogg-conv-utf8.diff
Tom