MKVToolNix 21.0.0

MKVToolNix is a set of tools to create, alter and inspect Matroska files under Linux, Mac, other Unices and Windows.

Freeware / Donate
14.9 MB
4.6 48 votes

With these tools one can get information about (mkvinfo) Matroska files, extract tracks/data from (mkvextract) Matroska files and create (mkvmerge) Matroska files from other media files. Matroska is a new multimedia file format aiming to become THE new container format for the future. You can find more information about it and its underlying technology, the Extensible Binary Meta Language (EBML), at

What's New:

Important notes

  • The MKVToolNix project now contains a Code of Conduct.
  • The MKVToolNix project’s source code repository, bug tracker and wiki have been moved to GitLab.

New features and enhancements

  • mkvmerge: splitting by duration, by timestamps or by timestamp-based parts: mkvmerge will now consider the first key frame within 1ms of the requested value to be eligible for splitting.
  • MKVToolNix GUI: the GUI will now save and restore the widths of columns in tree and list views. Implements #2057.
  • MKVToolNix GUI: header editor: when closing or reloading a modified file, the GUI will now focus the first element that’s been modified before asking the user for confirmation regarding discarding unsaved changes.

Bug fixes

  • mkvmerge: fixed reading text files encoded in UTF-16 order UTF-32 that have different forms of line endings (new lines, carriage returns or a mix of both). Fixes #2160.
  • mkvmerge: MP4 reader: fixed mkvmerge’s interpretation of edit list entries with segment_duration == 0 when there’s more than one edit list entry. In that case mkvmerge was reading the whole content more than once. Fixes #2152.
  • mkvmerge, GUI’s multiplexer: MIME types: added the font top-level media types from RFC 8081. This means that the following new MIME types for fonts can be used: font/ttf, font/otf, font/woff and font/woff2.
  • mkvmerge: MPEG transport stream reader: fixed slow speed on Windows due to lack of buffering.
  • mkvextract: fixed slow track extraction speed on Windows due to lack of buffering. Fixes #2166.
  • MKVToolNix GUI: multiplexer: changing the "subtitle/chapter character set" drop-down was ignored when the selected track was a chapter track. Fixes #2165.
  • MKVToolNix GUI: multiplexer: once a "subtitle/chapter character set" was set for a track it couldn’t be changed back to the empty entry (= auto-detection) anymore.
  • MKVToolNix GUI: header editor: fixed re-translating several displayed strings when the GUI language is changed if the language the GUI was started with was not English. Fixes #2159.
  • MKVToolNix GUI: header editor: whenever a file did not contain a "date" element in its segment information section, the GUI would erroneously ask the user to confirm discarding unsaved changes when closing or reloading the tab. Fixes #2167.
  • MKVToolNix GUI: job queue: jobs are now saved when their status changes in addition to when the program exits. Fixes #2168.