MKVToolNix v76.0 released

Here’s yet another release, v76.0. This is a slightly bigger one in terms of the number of fixed bugs & implemented improvements. Due to the change wrt. the handling of BlockAddition elements (which is required for HDR content for WebM, VP9, AV1`) I strongly recommend users to upgrade.

NOTE: Windows 11 users having problems with the dark mode & links being too dark: I’ve implemented a workaround for hat since the release. Please download & use one of the latest continuous builds.

You can download the source code or one of the binaries. The Windows and macOS binaries as well as the Linux AppImage are available already. The other Linux binaries are still being built and will be available over the course of the next couple of hours.

Here are the NEWS since the previous release:

Important notes

  • mkvmerge: removed the option --blockadd. Removing block additional data is not possible anymore, as it is often required for proper decoding. Part of the implementation of #3511.

New features and enhancements

  • mkvmerge: JSON file identification: added a child element called num_index_entries to the properties track element containing the number of index entries found for a track. Currently only implemented for Matroska files where it contains the number of cue points. See #3510.
  • mkvmerge: the maximum block addition ID track header value is now calculated automatically from both the existing mappings & the actually used block additions in the block groups. Part of the implementation of #3511.
  • mkvmerge: Matroska reader: when reading WebM files that use block additions with ID 4 (HDR for VP9) an appropriate block addition mapping will be created automatically. Part of the implementation of #3511.
  • mkvmerge: MP4 reader: the title/movie name meta data (content of the udta.meta.ilst.©nam atom) will now be copied over as the segment title track header attribute. Part of the implementation of #3475.
  • mkvmerge: MP4 reader: the comment & encoder meta data (content of the udta.meta.ilst.©cmt & ….©too atoms) will now be copied over as global tags COMMENT & ENCODER respectively. Part of the implementation of #3475.
  • mkvmerge, MKVToolNix GUI’s multiplexer: added an option to stop processing after the primary video track ends called --stop-after-video-ends. This discards any remaining packets of other tracks. Part of the implementation #3506.
  • MKVToolNix GUI: only on Windows: the GUI now uses Qt’s “Fusion” style instead of the deprecated “Windows Vista” style. The advantage is that as of Qt 6.5 the “Fusion” style properly supports Windows 10’s & 11’s dark application mode. The Windows binaries are now built with said Qt version. Therefore the option to disable the dark mode has been removed. Fixes #3264 and likely others.
  • MKVToolNix GUI: multiplexer: automatically setting the destination file name: added an option in the preferences for using the first source file’s directory name instead of its file name as the basis for the destination file name. Implements #3512.
  • MKVToolNix GUI: multiplexer: double-clicking on certain columns in the “tracks” view will now toggle them directly (columns “Default track” & “Forced track”) or activate the corresponding control (columns “Language”, “Name” & “Delay”). Double-clicks on other columns will do what they’ve done before, too: toggling the “Copy item” state. Implements #3513 & others.
  • MKVToolNix GUI: the dialog for editing language tags is now created only the first time the user wants to edit a language tag & cached afterwards instead of creating a new instance each time. This makes subsequent uses instant.

Bug fixes

  • mkvmerge: mkvmerge will now only try to probe for VobSubs if the name of the file to identify ends in either .idx or .sub, preventing mis-identification of other file types if VobSubs with the same base name exist in the same directory. Fixes #3508.
  • mkvmerge: AC-3: mkvmerge will now skip certain types of garbage data (16 bytes starting with 0x01 0x10) that can occur before each sync frame, fixing the file not being identified as AC-3. Fixes #3484.
  • mkvmerge: Matroska reader: when reading files that use block additions with IDs other than 1 (e.g. 4 for HDR for VP9) the IDs will now be kept & written to the output file. Before no ID would be written, effectively using 1 as that’s the default value for the corresponding element. Part of the implementation of #3511.
  • mkvmerge: mkvmerge will no longer write block addition mappings or the max block addition ID track header elements when creating a WebM file as those elements aren’t supported there. Part of the implementation of #3511.
  • mkvpropedit: fixed replacing chapters & tags in files that don’t contain tracks. Fixes #3498.

Have fun 😁

12 thoughts on “MKVToolNix v76.0 released

  1. Nikolaus Moll

    Hi, I noticed when I add IDX/SUB files to the sources, they appear “twice” now in the Stream List. Oder versions recognized the files as one Stream. Is this a wanted behaviour or a bug?

      1. Nikolaus Moll

        In older versions there was no problem adding both… and since they both belong together, that makes more sense for me.
        Tbh. the behaviour confused me so I had to check, if adding only one file will really merge both.

        1. mosu Post author

          mkvmerge has always processed both files; it automatically finds the .sub when you tell it to use the .idx (but not the other way around!). What happened in older versions was that the file type of the .sub was recognized, but it thought there were no tracks in it. The result was that there were two files listed in the files pane, but only one track (or rather, one set of tracks, all belonging to the .idx). You could remove the .sub again without affecting the track list, but due to the presence of the .idx the content of the .sub was still processed. Or to put it differently: adding the .sub effectively didn’t to anything at all.

          The effect of prior behavior was that sometimes people only added the .sub and were confused that there were no subtitle tracks, or worse — they didn’t even notice it!

          That behavior was arguably a lot worse. You were just used to it.

  2. Kajo


    I just updated from 75 to 76 and it seems that dark mode is broken now . “Disable the dark mode” is unchecked but I still get the light mode of the app. Restarting the app or rebooting doesn’t help. After reverting back to 75 dark mode works again.

    1. Kajo

      Should’ve read the whole news post I guess. XD

      After the installation of the newest revision it works fine.

  3. Markus

    Hi Moritz, v76 does not open on Mac OS 10.15.7? What am I doing wrong? Thanks for support – best/Markus

    1. mosu Post author

      No idea, sorry. Maybe a newer version is now required due to library updates? I don’t have a Catalina system to test with anymore.

    1. mosu Post author

      Report that to the author of gMKVExtractGUI. It isn’t my program; I cannot do anything about it.

      1. Mike

        I bet the most wanted feature for mkvtoolnix gui would be to have extraction features that gMKVExtractGUI has. I still don’t understand, after many years, why you refuse to do this. Yes, it would take time to implement it, but let’s be real here, it’s not that big of a job. You basically already have the “building blocks” for it GUI wise, and making few settings for output filename schemes would be quite easy (e.g. steal it from gMKVExtractGUI). You already have the cli tool in mkvtoolnix to do the extracting job (gMKVExtractGUI uses it). Why is this still not implemented? How many years have this feature been in “coming” state? ~10 years?

        It would be really helpful for many people, especially to users that just can’t hack with cli commands (extracting multiple tracks from a video is really not that easy with your cli tool, maybe for you but you’re obviously biased), and e.g. for linux users (no native tool to do this).

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