First of all, sorry for my bad English.
Problem happens with VLC version 2.1.1. I'm using MkvTagger (2013-04-03) to download movie tag data and embed xml into mkv. Before embedding, VLC plays the file just fine.
But with tags embedded, VLC freezes and it's process loads 100% of CPU. Every other player I tried plays that file without problems. Also I downloaded VLC 2.0.7 and it works fine. I think something went wrong in the newest version.