mkvtoolnix

• wget -q -O - https://mkvtoolnix.download/gpg-pub-moritzbunkus.txt | sudo apt-key add -
• sudo nano /etc/apt/sources.list
  • deb http://mkvtoolnix.download/debian/jessie/ ./
  • deb-src http://mkvtoolnix.download/debian/jessie/ ./

via: https://mkvtoolnix.download/downloads.html