Mkvtoolnix

Free open source cross platform set of tools and utilities for working with mkv container files. These tools are ideal for working with H.264 video in an mkv container.

(additional info coming soon...)

Uses

remove a subtitle track from a Matroska .avi file

note: It is recommended that you disable "header removal compression."

Run mmg.exe which is a GUI front end for the tools. open your mkv with it. uncheck whatever you don't want and then give it an output folder and name. click merge.

source: aedipuss on videohelp.com

crop off part of the matroska video (edit/split)

You can split a large MKV file in to multiple parts and in a user specified size. This is easy to do and explained well in a guide on TechFleece. Ref: How To Split MKV files using MKVToolnix

In this specific example, we want to remove the first few seconds of a matroska video (the first 27 seconds of the video and audio). Our particular video is 1:38:24 long. The individual distributing the video, a movie, decided to add his own custom logo sequence at the beginning (he goes by the handle TiCTaC). Cut as it may be, the logo sequence, which features his handle orbiting the earth to the tune of the Universal studio theme, causes the entire mkv movie to fail to play properly in VideoLAN Player and Windows Media Player. His logo sequence is encoded differently than the rest of the video stream. Many (most) video players get confused and therefore do not render any video after the initial custom logo sequence (video goes black at 27 seconds when the actual movie starts.) In short, TiCTaC breaks the video by prepending his logo sequence. We fix the video by cutting out the first 27 seconds, getting rid of the TiCTaC logo sequence incompatibility, thus allowing VideoLAN (VLC) and other players to play the entire video correctly. We also remove unneeded global tags. Follow these steps.

1. Load and run 'mmg.exe'
2. On the INPUT tab click 'add' and choose the mkv video file.
3. Under 'Tracks, chapters and tags:' uncheck the checkbox in front of the global tags.
4. Click on the GLOBAL tab
5. In the 'Splitting' section check 'Enable splitting...'
6. Click the '...after this duration:' radio button and enter '00:00:27'
7. For 'max. number of files:' enter '2'. (This is a VERY important step!)
8. Choose an 'Output file name' on the bottom of the interface and click 'Start muxing.'

By choosing 'max. number of files:' you prevent mkvmerge from creating thousands of tiny 27 second video files. We are basically splitting the video into 2 unequal sized files, the first being the 27 second logo sequence we can later discard, and the entire rest of the movie.

If you ever come into possession of a video or movie that will not play after the first few seconds, and has a custom logo sequence, you will likely resolve the problem by elimination of that first part of the video file.

support

header removal compression bug

Starting with v4.1.0 Mosu, the developer of mkvtoolnix, implemented “header removal compression”. Several hardware/software players don’t support header compression in mkvs. The benefit from header compression is minimal at best, it is best not to use header compression at all for compatibility purposes.

source: MKV Mania: Header Compression And The Side Effects by Damian

Version 5.8.0 allows you to set a default -
Run mmg.exe and open file options and put a check in disable header removal compression. Close mmg and then restart.