MKVToolNix is certainly one of the most popular MKV-related tools in the open source domain. Heir to the widely used and acclaimed MKVmerge GUI, this Graphical User Interface now integrates not only mkvmerge, but also mkvinfo, mkvextract, mkvpropedit, and mmg in this new “Little Earthquakes” edition. All of these utilities will allow you to merge MKV files, add or replace subtitles, extract specific streams, and inspect and edit their properties, headers, etc. MKVToolNix is open source and cross-platform, so that you can enjoy its extensive functionality in fifteen operating systems, including Mac OS X, Arch Linux, Ubuntu, Debian, Fedora, and others for free.
MKVToolNix attracts a varied array of users, both novice and expert. Some will use it to create new Matroska containers out of existing video files in various formats, while others will perform more delicate operations in their MKV files, such as changing some of their properties. The functionality you will find in the Merge menu option is based on mkvmerge’s contribution to the program. It allows you to turn the media streams (audio, video, and subtitles) in a, say, DVD or Blu-ray into a unique MKV file without losing any of their streams or their original quality. Also, you can customize this Matroska container by leaving out the streams you don’t need (such as soundtracks and subtitles in other languages, trailers, documentaries, etc.) and thus improve its portability and size. You can add additional streams to existing MKV files, such as a subtitle file in your own language or even a whole new soundtrack in a language that you can understand, and turn various video files in different formats into a compact, high-quality MKV file.
The functionality offered by mkvextract does the opposite – it allows you to pick specific streams (audio and video tracks, subtitles, attachments, etc.) and demultiplex (or demux) them into individual files that you can then use in future merging projects. Mkvextract is also capable of recognizinh and manipulating cues, time codes, chapters, CUE sheets, tags, etc., which now you can isolate into useful formats according to the track type of the original file.
Mkvinfo provides you with technical information about the selected track, while mkvpropedit is responsible for the functionality in the Edit Headers menu option. Here, those of you with a deeper knowledge of how media streams work can navigate through the various headers in any of the video or audio streams present in a MKV container and perform highly technical modifications in their content.
MKV merge and extraction jobs can be queued up and started manually whenever it suits you or launched right away. Either way, the program will produce excellent-quality MKV files playable in most media players. MKVToolNix is a comprehensive toolbox wrapped up in an attractive and intuitive interface.