Mkvtoolnix Online

48 thoughts on “ MKVToolNix v4.9.1 released ” k-r-69 July 12, 2011 at 14:42. Thanx for such quick respond and fixed build. Still a bit slow (3sec to open file of any size) – but work. How to merge subtitles with an MKV video using MKVToolNix MKVToolNix is a set of free tools to create, split, edit, mux, demux, merge, extract, and inspect MKV video files. It's available for Microsoft Windows, Linux, and macOS.


More Matroska related news can be found in my blog.


  • 2021-04-22: Added binaries for Ubuntu 21.04 'Hirsute Hippo'.
  • 2021-04-09: Released 56.1.0 (
  • 2021-04-05: Released 56.0.0 (
  • 2021-03-24: MKVToolNix for Windows is now available from the Microsoft Store.
  • 2021-03-13: Added a section to the 'downloads' page for a Docker image.
  • 2021-03-06: Released 55.0.0 (
  • 2021-02-28: Re-added packages for CentOS 8.
  • 2021-02-26: Released 54.0.0 (
  • 2021-02-19: Dropped support for Ubuntu 18.04 'Bionic Beaver' & 19.10 'Eoan Ermire '.
  • 2021-01-30: Released v53.0.0 (
  • 2021-01-04: Released v52.0.0 (
  • 2021-01-04: Dropped support for CentOS due to the recent change in the project's direction.


  • 2020-10-22: Added binaries for Ubuntu 20.10 'Groovy Gorilla'.
  • 2020-10-04: Released v51.0.0 (
  • 2020-09-06: Released v50.0.0 (
  • 2020-08-02: Released v49.0.0 (
  • 2020-06-27: Released v48.0.0 (
  • 2020-06-09: Added binaries for Raspberry Pi OS.
  • 2020-05-30: Released v47.0.0 (
  • 2020-05-01: Added binaries for Fedora 32 and Ubuntu 20.04 'Focal Fossa' (64-bit only).
  • 2020-05-01: Released v46.0.0 (

I streamed a few DJ sets over the last few weeks with a bunch of friends as part of ‘covidcore’, an online get-together while we’re all in isolation. It’s been a while since I’ve played any DJ sets but it was great fun and thankfully I didn’t make too many mistakes.

Mkvtoolnix online tv

Anyway, It was my first streaming experience and I found it a breeze to set up thanks to Twitch and OBS. When reviewing my recordings I noticed that my microphone level was pretty low so I decided to bust out the audio track from the video and raise it. Also when uploading my video to Youtube I also got a copyright notice about one the clips in my video which was subsequently being blocked, so I decided to edit that out too.

Here is how you can do it.

Note: I’m on a mac so all of the instructions are for that, but apart from installation the rest should be platform agnostic.


  • Install mkvtoolnix
  • Extract audio and video tracks from mkv file
  • Optionally convert audio track if editing needed
  • Merge audio and video tracks back in to mkv file

Install mkvtoolnix

mkvtoolnix is a set of command line programs for finding out information and modifying mkv (“Matroska”) files. You can install it with a GUI but I didn’t bother.

That’s it, boom!

Extract audio and video tracks from mkv file

For this step we are going to run this command

In the above command we are using mkvextract, part of mkvtoolnix, to extract the video track which is encoded using the ‘h264’ codec and also the audio track which is encoded using the AAC codec.

In order to find out what your video and audio tracks were encoded with use the following tool

Might be good to reference the docs if you have trouble there.

Optionally convert audio track if editing needed


My audio editor couldn’t open the aac file I created so I converted it to FLAC format using ffmpeg, another command line program that is insanely useful for converting audio formats (amongst other things).

So to convert I ran

Now I can open my flac file and edit the parts I want, like amplifying my microphone in the recording.

Merge audio and video tracks back in to mkv file

Right, now you have completed your editing we can stitch them back together again using the mkvmerge command

Mkvtoolnix online, free

You can see I just merged the flac formatted audio back in. I just tried it and it worked. I need to read up a bit more on file formats to be honest so if you need more info check the docs.

Mkvtoolnix Online Games

Hope that helps someone :)