MKVToolNix v4.9.1 released


I’ve released mkvtoolnix v4.9.1. It fixes two servere bugs that were introduced with v4.9.0.

Here are the usual links: the home page, the source code and the Windows installer and 7zip archive.

Most of the binaries that I provide myself are still being built and will be available tomorrow.

Here’s the full ChangeLog since release 4.9.0:

  • 2011-07-11 Moritz Bunkus <>
    • mkvmerge: bug fix: Fixed endless loop when reading AVI files on Windows if MKVToolNix was compiled with a gcc mingw cross compiler v4.4.x. Fix for bug 642.
    • mkvmerge: bug fix: Fixed long file identification time caused by DV detection. Fix for bug 641.

48 thoughts on “MKVToolNix v4.9.1 released

  1. k-r-69

    thanx for such quick respond and fixed build.
    all work again. still a bit slow (~3sec to open file of any size) – but work.

  2. KM

    Thanks for the update. Works well on Linux Mint 11, based on Natty.

    However I can’t import the keyfile with Synaptic, no error message either, it just doesn’t happen.

    I have 6 other external keys imported so it should work ™?

    1. mosu Post author

      Do you mean the gpg key? It’s a normal gpg key, and I have no idea why it shouldn’t work.

      1. KM

        Yes, that’s the one. I can import it into the generalkey storage in Mint, so it seems to be a valid key and not corrupted. But can’t add it to Synaptic to validate the PPA…

        Curious if anyone else have experienced this with this key?

          1. KM

            Key works with Lucid that I have on another PC…

            It’ll probably go away with some update, some day :-)

  3. lapje

    Hello there,

    first: myn thx for these update. But one question:
    is there any chance in further versions to choose at mkvmerge GUI compression at extra options vor all streams with one click? my LG BD 390 didn’t support these compression and its annoying to choose ist at every file for every stream…

  4. Daniel

    Is it possible that MKVToolNix has trouble splitting files with already-compressed headers? With header compression becoming more and more predominant in Matroska files, I have noticed that increasingly often when I split a file with mkvmerge, the first segment will play fine while the further one’s won’t play correctly with any of the players I tried. VLC displays artifacts in the video, and both video and audio tracks jump back and forth, stutter, etc.; MPC-HC and WMP (with Haali Splitter) the sound is fine but the video speed is very inconsistent, oscillating between too slow and too fast.

    Fron inspecting a few headers of both files where this happens and files where it doesn’t, I suspect it happens only for files with header compression. Judging by how I understand header compression to work, and the fact that only the second and subsequent segments show the issues, I would suspect that mkvmerge fails to rebuild a full header for these segments. The issues also persist if I manually deactivate compression for all tracks before splitting (I suppose the option does not decompress already-compressed headers).

    I didn’t want to file a bug report because I don’t feel like I know enough about the issue just yet; just hoping for someone to have some further insight? I’m quite surprised that no one else seems to have brought these issues up yet.

    1. mosu Post author

      That does sound like a bug. Filing a bug report would be nice because I might forget about it otherwise.

  5. Russell Burrows

    Mkvtoolnix crashes after adding a file.
    I am on Ubuntu 11.
    Is there any way to fix this crashing bug?

    1. mosu Post author

      Sounds like a bug. Can you upload the file for which mkvmerge crashes to my FTP server so that I can take a look at it, please? The address is “”, user name “upload”, password “only” (each without the quotes).

  6. Russell Burrows

    Kind Sir Mosu,

    I checked a few times and I noticed on further observation that I open MKV Toolnix and I let it just run and ten to twenty seconds later it automatically closes/stops running??

    I love MKVToolnix and wanted to say thank you for this excellent program.

    I used this great program many times on this laptop when on Ubuntu 10 but since the upgrade to Ubuntu 11 this results in MKVToolnix autoclosing after a few seconds even if no buttons are pressed other than sound/video > MKV Merge GUI.

    However MKV info runs fine and never crashes or auto closes??

    I just wanted to say thanks once again for such a good program in MKV Toolnix.

    Thank you.

    Russell Burrows.

    1. mosu Post author

      Sounds like the online check for available updates crashes mmg. You can cross-check by running “mkvmerge –check-for-updates” ; it should crash as well.

      I remember that there was some error in libcurl recently (the library mkvtoolnix uses for online access), and that updating to a newer version fixed the issue. It wasn’t an issue in mkvtoolnix itself.

  7. Russell Burrows

    Kind Sir. Mosu.

    I tried updateing via Synaptic but it gave me this error message:

    W: GPG error: ./ Release: The following signatures couldn’t be verified because the public key is not available: NO_PUBKEY BCCF7AF0B6571FCA

    Thank you.

  8. Russell Burrows

    Kind Sir Mosu.

    I opened the key in a text editor and saved it and then added it to my software sources.

    Then I did sudo apt-get update for mkvtoolnix and mkvtoolnix gui and it updated and then told me it was using the latest version.

    Then I went to sound/video mkvmerge gui and after launching it still lasts twenty seconds before autoclosing.????

    I rebooted and tried again but still same result??

    Thank you.


    1. mosu Post author

      It’s a bug in the libcurl library. As long as that isn’t updated in Ubuntu/Debian you can only turn off update checks in mmg itself. For that start mmg (be quick now, you only have 20 seconds), hit Ctrl-P for the preferences dialog, then un-check the “check online for updates” option (second up from bottom).

  9. Russell Burrows

    Kind Sir Mosu.

    I tried uncheck online updates and check ok and it autocloses and on next launch it had the check online updates button still selected.

    I managed to at last fix it by unchecking the online update button, pressing ok and pressing the X button to close MKVmerge before it autoclosed to make permanent the uncheck online updates.

    I was very happy that the crashing bug was fixed.

    And I again say thank you for such a wonderfull program as I am now able to redo my vacation videos to Disney land with no compression so that we can use mkvtovob to watch our Disneyland footage on the PS3.

    Thank you Sir.

  10. Bilberlip

    Hi folks,
    Just wanted to say, great program, thank you.
    And ask if a totally insignificant feature might one day be added?
    Sometimes you get an MKV file with literally dozens of unwanted, even unnecessary inputs/ID’d in the MKV file. On some, files, when you have 30 sub files, chapter files, audio’s etc., and all you want is the main video and audio, each has to be scrolled to and unticked? I know, it takes all the strength garnered from that days bowl of Wheaties to do this laborious task, but would it be hard to put an option on the interface, “untick all” /tick all. etc.?
    Thank you again! Just a thought?

  11. Manuel Ramirez

    Dear Mr Mosu: first all thanxs very mauch for your programas, i am using mkvmerge 4.0.0, and ihave a problem, i tried to divide a 3d mkv 6gb film in two parts, then i put those parts en my usb (you know about the FAT32 only accepts 4gb files), to see it in my tv, the first part was ok theres no problem then the second one i just saw a few seconds then stopped it…i ve tried again with other 3d mkv 8gbfilm, and divided in 3 parts,again the first one ok, then the second and third part i couldnt see nothing, please help me…thanks you and sorry for my english

      1. Manuel Ramirez

        Yes sir i am using 4.0.0.
        and please could you explain it i just understand 50% ..

        1. Manuel Ramirez

          specially this part….. A temporary solution is to re-mux such files turning off extra compression for all tracks…

  12. bkackmark

    Dear Sir MoSu!

    Thank you for these upadate. But one problem:
    I using mkvmerge GUI ver 4.9.1 to Muxing VOB file
    Input: VOB file
    Output : mkv file
    But when I run .mkv(output) file with VLC media player V 1.0.1 then it stop and hang at last second.
    I am test several .VOB file them the same that.
    Please tell me why and how can I correct it.
    Thank you so much

  13. Josef

    many thanks for this great program. I’m using MKVToolNix GUI 4.9.1.
    Now I have two MKV-files (Part_1 and Part_2) with 4 tracks each: video, audio, subtitle and chapters. I use the “append”-button to append Part_2 to Part_1.
    And it worked for the video-track. Also no problem with the audio-track. But the subtitle-track of Part_2 is not appended but merged into the subtitle-track of Part_1. Same with chapters-track. So I have to set a delay for the subtitle-track of Part_2 (which is equal the runningtime of Part_1). This works. With the chapters-tracks, I have to correct the chapters manually with “Chapter Editor”.
    Question: is this the way I have to do it or is it just a bug in the append-subroutine?
    Regards, Josef

    1. mosu Post author

      There are many possible reasons why such manual correction may be necessary. This is most likely not a bug, or if it is then it won’t be fixed/worked on.

  14. püppi

    Hi mosu, could you make mkvextract accept .webm files? As WebM is a subset of Matroska, this should be a minor change. Currently it doesn’t accept a file with extension .webm, but when I rename the file to *.mkv it works.

    1. mosu Post author

      mkvextract accepts any Matroska/WebM file regardless of its extension. My guess is that you’re using one of the GUIs available for mkvextract and that that GUI doesn’t accept WebM. Please take that up with the GUI’s developer.

  15. dirtyharry

    how can i merge a idx/sub pair with a mkv file (not my rip)?

    i can add the idx just fine but the sub is rejected saying “it does not contain any tracks”.

    having the mkv and the idx/sub files in the same folder plays the mkv just fine, however, so there seems to be nothing wrong with the sub file.

    any help would be much appreciated.

  16. sukanime

    Thanks for the Tool,
    I Just want to ask, could you make Mkv Extrack GUI for Linux?
    Sometimes i need to translate some subtitle to my own language, and i need to extrack subtitle from the movie.
    Then Merge it using Mkv Merge GUI.


    1. mosu Post author

      No, sorry. There’s nothing I enjoy about GUI coding, and I have very little time for coding in general. Therefore I will never write a GUI for mkvextract.

  17. red

    Hi mosu, I am muxing MKV’s with SRT files and facing a problem. When i add an abc.MKV into mkvmerge GUI and a Srt, the ‘File/segment title’ (under Global tab) is taken automatically from the MKV loaded. After muxing is done, i select ‘remove all’ and start with the next xyz.MKV. But the old title (abc…) is still present and overwrites the older value of ‘File/segment title’ into the xyz.MKV being muxed. If i clear the ‘File/segment title’ manually and then load xyz.MKV then title is taken from the freshly added file (xyz…). This is also preventing me from using the job queue because after muxing say 5 MKV’s, all had the same title.
    Interestingly however, if i have enabled the option (mkvmerge GUI>File>Options>) ‘clear inputs after a successful muxing run’, then the title is muxed correctly (the value from ‘File/segment title’ is erased automatically). Shouldn’t the ‘File/segment title’ be cleared if i click ‘remove all’?

    Kindly look into it. Using mkvmerge GUI v4.9.1, win 7 32-bit ultimate.

    BTW, Awesome app.
    Thanks and Regards.

    1. mosu Post author

      No, the title should not be removed. That’s not the intention of the “remove all” button. If you want to start over completely then use “File -> New”.

  18. Watson


    I’ve got a little problem with audio sync which i pinned down to either mkvextract doing something wrong or the AC3 container not saving bitrate precisely.

    First off, I’m re-encoding MKV files by demuxing the AC3 audio, encoding the video with x264, encoding the audio with besweet and muxing the resulting streams together again.

    Now with some files i noticed that the audio runs notably out of sync after a while (in an example file ~0.4 seconds after one hour). My first thought was besweet screwing up something.

    So i demuxed the audio with mkvextract and directly remuxed it with mkvmerge… and the audio was out of sync already. Spent some time searching and did not really find something useful until i ran across mkvalidator.

    Checking the files with mkvalidator, the audio bitrate in the source was 192027 bits/s while the audio bitrate in the directly muxed file was 192006 bits/s.

    The difference in those bitrates matches quite well the sync issues, and I found no other solution to date than to manually change the framerate of the stream in besweet.

    The fun does not end here though.

    As long as I keep the stream inside a matroska container (e.g. remuxing only the audio to .mka) the bitrate doesn’t change. When i remux the previously demuxed .ac3 together with the stream inside the .mka, both streams end up with 192010 bits/s. Remuxing them to separate .mka files yields one with 192027 bits/s and one with 192006 bits/s again. mkvinfo also returns different lengths for both streams, despite them actually being the same.

    Now my question is, does the issue lie within mkvextract (or any other of the tools) or the AC3 container?

    Thanks and regards.

    1. mosu Post author

      In Matroska each frame/packet has its own timecode. When you mux from one Matroska file into another one then mkvmerge will re-use the source container’s timecodes. That’s why the “bitrate” doesn’t change.

      The AC3 “container” doesn’t have timecodes. Therefore this information is irrevocably lost when you extract into an AC3 file. Muxing that AC3 file into a new Matroska file requires mkvmerge to calculate new timecodes.

      No bug here. Just a limitation of the involved containers/formats.

      1. Watson

        Thanks for the info.

        I also investigated and tested a bit further, an encode with eac3to directly from the mkv gave me quite a few “audio overlap” warnings, so I guess those already existent overlaps are the culprit to my problem.

        I take it mkvextract demuxes the whole stream without cutting those overlapping sections? In that case, an option to fix those overlaps would be a handy addition.

        Best regards.

        1. mosu Post author

          mkvextract simply extracts the data as it is. It will never cut off anything; that is not its purpose. Sorry.

          1. Watson

            Yeah, I just realized it would have to decode and interpret the underlaying streams for that, and such is not the purpose.

            Thanks anyways.

  19. iReNe

    Dear Sir;
    The file was 8gb on my desktop n i used MkvToolNix to split it into 2parts so that i can move them into my FAT32 HDD.This is the error i got when using MKVToolNix 5.6.0 to join back the 2parts of MKV files when i hv over 300gb in my FAT32 HDD.
    Is it because the HDD is FAT32 which makes them unable to join?

    Error: Could not write to the output file: 112 (There is not enough space on the disk.)
    Error: Could not write to the output file: 112 (There is not enough space on the disk.)

    Kkindly guide.
    By the way,thanks a lot for ur work.It’s really awesome.

      1. iReNe

        I see.Glad that I got a confirmation from u, at least i can stop trying now,LoL!

        Once again,thanx fer the hard work.
        Really appreciate ur help.

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