MKVToolNix is a set of tools to create, alter and inspect Matroska files under Linux, other Unices and Windows.
https://mkvtoolnix.download/
apt-get install mkvtoolnix-gui
Работа с видео в Linux. Часть 4. Mencoder, Avimerge, Mkvtoolnix, Vorbis - рецепты.