Ok, i found out what the problem is!! The file is tagged with ID3v1, ID3v2 and APE tags. For some reason, the ID3v2 is also cut off after 30 letters like the ID3v1. Thr reason foobar2000 gets it right is that foobar2000 prefers APE tags over ID3v2, while taglib does it the other way round! Sorry for bothering you with this ;)