MKVToolnix is a set of tools to create, alter and inspect Matroska
files. With these tools one can get information about Matroska files
(mkvinfo), extract tracks/data from Matroska files (mkvextract) 
and create Matroska files from other media files(mkvmerge). Matroska 
is a new multimedia file format aiming to become THE new container 
format for the future. 

MKVToolnix requires libebml, libmatroska and wxGTK, all of which
are available on Slackbuilds.org.