MKVToolNix is a collection of tools for the Matroska media container format by Moritz Bunkus including mkvmerge.

The free and open source Matroska libraries and tools are available for various platforms including Linux and BSD distributions, macOS and Microsoft Windows.

The tools can be also downloaded from video software distributors[4][5][6][7] and FOSS repositories.

[9][10][11][12][13][14][15] The tools are cited in patents for a "Universal container for audio data".

[16] A "portable" Windows edition exists, but is not yet[update] available in the PortableApps format.