MKVToolNix

MKVToolNix is a collection of open-source tools for creating, inspecting, and editing Matroska (MKV) multimedia container files. The project’s core component, mkvmerge, is complemented by a set of utilities including mkvinfo, mkvextract, and mkvpropedit, as well as a graphical user interface called MMG. The tools are cross-platform, available for Windows, macOS, and Linux, and are designed to work together to manage Matroska streams without re-encoding.

Key capabilities include multiplexing multiple video, audio, and subtitle tracks into an MKV file, extracting tracks from MKV files, and editing metadata such as titles, languages, and attachments. MKVToolNix can also manage chapters, track properties (default track, forced subtitles), and attachments like fonts or cover art. It supports a wide range of input formats for muxing and preserves lossless quality when remuxing existing MKV files. The suite can also output debug information about Matroska files and handle advanced codec parameters.

Component overview: mkvmerge, the primary muxing tool; mkvinfo, which prints a detailed structural summary; mkvextract, which extracts tracks; mkvpropedit, which modifies file properties without remuxing; and the MMG GUI that provides a user-friendly interface. The project builds on the EBML framework that underlies the Matroska format and emphasizes extensibility and precise metadata handling.

Licensing and availability: MKVToolNix is free software released under the GNU General Public License, version 2 or later. It is maintained by the MKVToolNix Team and has a dedicated official site and repository where releases and documentation are published. The toolkit is widely used in media workflows for ingest, archiving, and post-production tasks involving Matroska files.