MKVToolNix is a free open source cross-platform collection of media tools developed by Moritz Bunkus and first released on 2003-04-30. The software was primarily built to edit Matroska media containers, but it also works with MP4, AVI, and even RealMedia. The software is written in C++ and uses Qt5 for user interface.
Some of the features of MKVToolNix include:
- Supports common media containers.
- Add and remove audio and video tracks from a container without having to re-encode them.
- Add and remove subtitles, menus, and chapter information.
- Add, edit, and remove meta data.
- Has pre-made binaries for 20 platforms.
While looking for a way to eliminate the unnecessary audio and video channels from media files I had, I found this tool. I was surprised, not only at how easily it could clean up my files, but that it worked with all of the video formats I used it on. The program helped me save several gigabytes of space in my video folder by allowing me to eliminate unnecessary media in the containers.