MKVToolnix is a set of tools to create, alter and inspect Matroska
(and WebM) files. With these tools one can:

* Get information about Matroska files (mkvinfo) * Extract tracks/data
from Matroska files (mkvextract) * Create Matroska files from other
media files (mkvmerge) * Modify properties of existing Matroska files
(mkvpropedit)

MKVToolnix requires wxGTK/wxPython all of which are available on
Slackbuilds.org and it comes with internal versions of libembl and
libmatroska.  Configure will use the internal versions if it fails
to find systemwide

Interested parties can build QT version of GUI by passing QTGUI=yes

Note: Mkvtoolnix build will try to use system libmatroska and libembl
and if they don't exist or unusable, then it will build Mkvtoolnix 
linking with them.