How to Join Videos without Conversion using MKVToolNix

join videos mkvtoolnix

This post is a follow up to the one on free tools that can join videos without conversion. The explanation on how this works as well as the conditions for this to work are in that post, so make a point to read through it should you encounter problems joining your videos as detailed below.


1. Get and install MKVToolNix from the homepage here. It's available for almost all platforms out there (Windows, Mac, Linux, BSD etc.) however I'll be using the Windows version here. There's also a portable version should you not want to use the installable one.

2. Run MKVToolNix GUI then add your first video by dragging and dropping it into the Source file box. Drag and drop the rest of the remaining videos in the order you wish to join them and when you get prompted, select the Append to existing file option.
Add and Append Videos

You can also add the videos using the Add source files button at the bottom of the window. After adding the first video, the remaining videos will have to be appended to it. To do that, select the loaded video then click on the the small arrow on the "Add source files" button then select append files.
Append Video Files to Join

  • For DVD VOB files that haven't been renamed (i.e. VTS_XX_X.VOB), MKVToolnix automatically adds and appends the remaining videos in the folder when you drag the first part. This makes it easy to join DVD VOB files into one MKV with no quality loss.
  • For DVDs that have title, root and/or chapter menus, make sure to not add their VOB parts. Only load the parts that have the actual video.

3. In the tracks, chapters and tags box, confirm that only two codecs are there - one for the video (e.g. MPEG-4/AVC/h.264, MPEG1/2) and the second for the audio (AC-3, MP3, DTS etc.). If you have an extra video or audio codecs listed there the process will not work as the videos need to be in the same codec format for them to be joined. Detailed explanation here. If the video(s) has embedded subtitles, it will also be listed there.
Make sure all the videos have the same codecs

4. Before finishing the process, you may want to edit some properties of the video though it's not necessary. These includes properties such as the default languages, frame rate, aspect ratio, adjustment of time codes (delays or stretch) etc. To do that, just select the video or audio item in the tracks, chapters and tags box, then in the properties box adjust the properties as you wish.
Edit Properties

5. Select the output folder and adjust the file name in the destination file, otherwise leave it as it is to output the MKV in the same folder as the source files. To finish, just hit the Start multiplexing button and wait for the muxing to complete. You can also Add to job cue which allows you to add other muxing jobs so that you can the jobs in batch.

6. Depending on the size of the video, the muxing will take from a few seconds to a few minutes to finish the job. The process may end with some warning and/or errors which you can look in the job output page. You can ignore the warnings though errors may mean that the job did not complete successfully. Regardless, make sure to open the output video to verify it joined well - check the length and that the audio/video sync.

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