After reading someone is speaking about Sebastian Dröge ...
"He is currently working on fixing the long term painful issue of
accurate seeking in mp3 files, which has been causing pain and problem
for both Pitivi and Jokosher for a long while. Not a highly
screenshootable effort, but none the less a very critical one"
... I found out, this is some interesting progress on an really old Akos
bug in GStreamer. It's renamed because of a new plugin who is gonna
handle this.
"Bug 308312 – Make mp3parse plugin implement GST_SEEK_FLAG_ACCURATE"