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MKVToolnix 54.0.0 “F Maj Pixie”

1 Star2 Stars3 Stars4 Stars5 Stars (20 votes, average: 3.90 out of 5)
MKVToolnix 54.0.0 “F Maj Pixie”

MKVToolNix is the one of the best collection of tools (mkvmerge, mkvinfo, mkvextract, mkvpropedit and mmg) for modifying MKV files.

With these tools one can get information about (via mkvinfo) Matroska files, extract tracks/data from (via mkvextract) Matroska files and create (via mkvmerge) Matroska files from other media files. Matroska is a new multimedia file format aiming to become THE new container format for the future. You can find more information about it and its underlying technology, the Extensible Binary Meta Language (EBML), at

The graphical user interface (GUI) allows you to manipulate Matroska (MKV) files in several ways. You can use those tools to create, split, edit, mux, demux, merge, extract or inspect Matroska files.

MKVToolnix will also work with other video formats. Such as AVI, MPEG, MP4, MPEG, Ogg/OGM, RealVideo, MPEG1/2, H264/AVC, Dirac, VC1.

And more as well as some video codecs such as VP9 video codec support – reading from IVF, Matroska, WebM files, extract to IVF files.

Moreover the program can work with audio files such as AAC, FLAC, MP2, MP3, AC3, DTS/DTS-HD, Vorbis, RealAudio. And also work with most subtitle formats including SRT, PGS/ SUP, VobSub, ASS, and SSA.

It is a cross-platform application that will work on Microsoft Windows (both 32 and 64-bit versions), Apple macOS and Linux operating systems.

Here is also the portable version which does not require installation. You just need to start the function. It can also be stored on external devices and run on any computer you have access to.

Changes in MKVToolnix 54.0.0 “F Maj Pixie” (2021-02-26):

New features and enhancements

  • mkvmerge: added support for using ISO 639-3 language codes in IETF BF47 language tags.
  • mkvmerge: AC-3 parser: added support for byte-swapped AC-3 data.
  • mkvmerge: Matroska reader: for audio tracks that have the bit depth track header set mkvmerge will now keep that header even for codecs that don’t require it for decoding.
  • mkvmerge: MPEG transport stream reader, PCM audio tracks: mkvmerge will now re-order the channels for 5.1, 7.0 and 7.1 channel tracks from the Blu-ray layout to the WAVEFORMATEXTENSIBLE layout expected in Matroska.
  • mkvmerge, mkvinfo, mkvpropedit, MKVToolNix GUI: added support for the following new track header elements: “hearing impaired” flag, “visual impaired” flag, “text descriptions” flag, “original” flag, “commentary” flag.
  • MKVToolNix GUI: added support for using ISO 639-3 language codes in IETF BF47 language tags. As there are several thousand of them, they’re deactivated by default and must be activated in the preferences (“GUI” → “Often used selections” → “Languages”).
  • MKVToolNix GUI: multiplexer: when adding Blu-rays the user can select multiple playlists to add simultaneously in the “select playlist to add” dialog.
  • MKVToolNix GUI: multiplexer: the file name extensions “eb3” and “ec3” were added for Dolby Digital Plus & “mpl” for Dolby TrueHD in the file dialogs.
  • MKVToolNix GUI: multiplexer: when adding multiple files the dialog asking the user what to do with them has gained a new checkbox. If enabled, all files containing at least one video track will always be placed in newly created multiplex setting.
  • MKVToolNix GUI: multiplexer: added a menu entry in the “Multiplexer” for adding all files that are currently in the clipboard.

Bug fixes

  • all: Windows: fixed compatibility with gettext 0.21 and newer on mingw.
  • all: Windows: fixed several of the programs having problems with certain Unicode characters (primarily emojis) in file names (e.g. mkvextract wrongfully complaining about an “invalid mode” or the GUI not being able to find parts of Blu-ray file structures).
  • mkvextract: AAC: fixed wrong channel mask field in the ADTS headers for 7.1 channel layouts. Fix by Tom Yan.
  • mkvextract: h.265/HEVC extraction: if the first frame starts with the parameter sets (SPS, PPS & VPS), the ones from CodecPrivate aren’t written and the ones from the first frame are kept.
  • mkvmerge: fixed the calculation of chapter timestamps read from NTSC DVDs. Fix by Tom Yan.
  • MKVToolNix GUI: IETF BCP 47 language widget: the language combo box will now always contain the language code the user enters in the free-form field, even if it isn’t in the list of often-used languages the user configured in the preferences.
  • MKVToolNix GUI: multiplexer: when browsing for the destination file name the default directory is now chosen according to the preferences regarding how the destination file name should be formed. For example, if the policy is set to “fixed output directory” then that output directory will be the one initially set when the directory selection dialog is opened.
  • MKVToolNix GUI: multiplexer: fixed the removal of appended source files if the “delete source files” end-of-job action is enabled.
  • MKVToolNix GUI: chapter editor: when importing chapters from DVDs the IETF BCP 47 language elements will be set, too, not just the legacy language elements.

Build system changes

  • libEBML v1.4.2 and libMatroska v1.6.3 are now required. The optional, bundled copies of both libraries have been updated to those versions. This bump in requirements fixes several heap overflow bugs in libEBML.
  • MKVToolNix is now using the C++17 library feature “file system library” instead of Boost’s “file system” and “system” libraries. For the GNU Compiler Collection (gcc) libstdc++ this means v8 or newer is required; for clang’s libc++ it means v7 or newer. For macOS this means that provided disk image will only run on 10.15 “Catalina” or newer.

Changes in MKVToolnix 53.0.0 “Fool’s Gold” (2021-01-30):

New features and enhancements

  • mkvmerge: AVI reader: added support for reading the video aspect ratio from the video properties header (`vprp` chunk) if present and setting the display dimensions accordingly.
  • mkvmerge: MP4 reader: for h.264/AVC tracks that don’t have an `AVCConfigurationBox` (`avcC` atom) in their sample description (`stsd`) atom or whose `avcC` atom contains no content `mkvmerge` will now re-derive the `AVCConfigurationBox` from the bitstream.
  • mkvextract: mkvextract will now check if any of the destination file names is the same as the source file name and abort with an error if that’s the case.
  • MKVToolNix GUI: when querying the user for a file name for saving things (e.g. multiplexer settings or an attachment in the header editor), the automatically suggested file name will now be based on the situation-specific file names (e.g. the destination file name for multiplexer settings or the attachment’s name when saving an attachment in the header editor) instead of the directory’s name.
  • MKVToolNix GUI: multiplexer: when deriving track languages from file names the GUI will now select the right-most match instead of the left-most one. For example, “La.vie.en.rose.(fr).srt” will now be detected as French (fr) instead of English (en).
  • MKVToolNix GUI: preferences: the items in the “pre-defined …” lists can now be renamed by double-clicking with the mouse or pressing the F2 key.
  • Windows installer: the `bluray_dump` command-line utility will be installed into the `tools` sub-directory. `bluray_dump` can read & dump certain file types used on Blu-rays: `.mpls` playlists, `.clpi` clip information databases, `.bdmv` index files, `bdmt_….xml` disc library databases and `tnmt_….xml` track & chapter name databases.

Bug fixes

  • mkvmerge: stretching chapter timestamps with `–chapter-sync` now works correctly with floating point values including fractions of floating point numbers (e.g. `12.3/45.67`). The tooltips in the GUI have been adjusted accordingly.
  • mkvmerge: MPEG 1/2 video handling: the “default duration” header field was often half the value it actually should be, resulting in all video frames having an explicit block duration with the correct value. This has been fixed with a patch by Tom Yan.
  • mkvmerge: MPEG 1/2 video handling: the data stored in `Codec private` and `Codec state` doesn’t contain extensions other than sequence & sequence display extensions anymore.
  • mkvmerge: tag handling: when remuxing a Matroska file with the `–no-track-tags`, existing `SOURCE_ID` track tags are now skipped, too.
  • MKVToolNix GUI: multiplexer: the drop-down boxes with pre-defined track names now follow the order set in the preferences instead of sorting the entries alphabetically.

Changes in MKVToolnix 52.0.0 “Secret For The Mad” (2021-01-04):

New features and enhancements

  • MKVToolNix GUI: job queue: the maximum number of jobs to run concurrently can now be increased in the preferences. The default remains at 1.
  • MKVToolNix GUI: the GUI will now add a context-specific default extension to file names selected for saving on platforms that don’t add one itself (e.g. GNOME). For example, when saving multiplexer settings the extension `.mtxcfg` will be added.
  • MKVToolNix GUI: added an option to the preferences for the window to stay on top of other windows.

Bug fixes

  • mkvextract: h.265/HEVC extraction: the code for skipping extraction of prefix SEI NALUs in the first frame was skipping two bytes too few, resulting in broken processing of all following bytes. Patch by Mike Chen.
  • libEBML: the optional, bundled version of libEBML was updated to v1.4.1.

Build system changes

  • libEBML v1.4.1 is now required due to a bug in libEBML that caused pointers to just-freed memory being returned to the caller under certain invalid data constellations, causing use-after-free errors in all of MKVToolNix’s programs.

Changes in MKVToolnix 51.0.0 “I Wish” (2020-10-04):

New features and enhancements

  • mkvmerge, mkvpropedit, MKVToolNix GUI: IETF BCP 47 language tags: added missing support for UN M.49 regions for which there are no corresponding ISO 3166 alpha codes. This enables language tags such as `es-419` = Spanish in bLatin America and the Caribbean.
  • MKVToolNix GUI: IETF BCP 47 language tags: the text in the widget displaying the current language & the corresponding edit button is now displayed like a link (depending on the theme: different color & underlined), making it clearer that not just the edit button can be clicked but the text, too.

Bug fixes

  • mkvmerge: AV1 parser: fixed mkvmerge crashing after uncaught exceptions due to certain data conditions. Found by fuzzying.
  • mkvmerge: AV1 packetizer: the duration of frames wasn’t set properly. When appending AV1 IVF or OBU files this meant that the last frame of the Nth file and the first frame of file N+1 had the same timestamp.
  • mkvmerge: DTS reader: fixed handling of buffers with an odd length when byte-swapped DTS is detected so that mkvmerge doesn’t abort with a failed assertion. Found by fuzzying.
  • mkvmerge: h.264/AVC and h.265/HEVC elementary stream readers: mkvmerge will no longer claim to recognize data that looks like AVC or HEVC but with invalid video width/height values as that lead to failed assertions in libEBML later. Found by fuzzying.
  • mkvmerge: h.265/HEVC parser: fixed mkvmerge aborting after uncaught exceptions due to certain data constellations found by fuzzying.
  • mkvmerge: IVF reader: fixed mkvmerge crashing with a “division by zero” error due to certain data conditions. Found by fuzzying.
  • mkvmerge: fixed mkvmerge aborting with a “division by zero” error due to the timestamp scaling factor being 0 after handling certain data constellations found by fuzzying.
  • mkvmerge: track statistics: fixed a “division by zero” error when the content’s shorter than 1ms. Found by fuzzying.
  • mkvmerge, mkvinfo, mkvextract, mkvpropedit: Matroska access class: fixed an invalid memory access under certain data conditions. Found by fuzzying.
  • MKVToolNix GIU: IETF BCP 47/RFC 5646 language tags: the GUI will no longer open the language dialog when clicking on a disabled language display widget.
  • MKVToolNix GUI: IETF BCP 47 language tags: the “variants” combo-boxes were not populated even when the language tag was valid and contained at a variant.
  • MKVToolNix GUI: IETF BCP 47 language tags: when no language is selected, at least one of the other components (extended subtags, region, or variants) has something selected and “private use” is not empty, the GUI would claim this to be a valid tag, which it isn’t.
  • MKVToolNix GUI: multiplexer: when the tracks/chapters/tags selection changes from “at least one entry selected” to “no entry selected”, the input controls will be reset to their default state and not just disabled.

Build system changes

  • * `configure` now checks for the presence of the a system-wide installed copy
    of the JPCRE2 C++ wrapper library for the PCRE2 library and uses that if
    it’s new enough (at least v10.32.1). If not, the bundled version will be
    used as a fallback.

Changes in MKVToolnix 50.0.0 “Awakenings” (2020-09-06):

New feature: IETF BCP 47 language tags

  • I’ve written up a [nice FAQ entry] about the switch to using IETF BCP 47 language tags, how they interact with legacy language elements, how the programs actually behave and how to disable their use if necessary.
  • mkvmerge: IETF BCP 47/RFC 5646 language tags: mkvmerge will now accept full BCP 47 language tags for all options taking a language. mkvmerge will always write “LanguageIETF” track header elements. If the language tag contains a valid ISO 639-2 language code it will also set the legacy “Language” track header element to the included ISO 639-2 code.
  • mkvmerge: IETF BCP 47/RFC 5646 language tags: if present the “LanguageIETF” track header element will be reported as the `language_ietf` property in JSON identification mode.
  • mkvmerge: IETF BCP 47/RFC 5646 language tags in chapters: mkvmerge will now write “ChapLanguageIETF” elements when creating chapter atoms, either when reading the simple chapter format or when generating chapters due to the `–generate-chapters` command line option.
  • mkvmerge: IETF BCP 47/RFC 5646 language tags in tags: mkvmerge will now write “TagLanguageIETF” elements when creating “simple tag” elements, either when reading tag XML files or when generating them.
  • mkvmerge: IETF BCP 47/RFC 5646 language tags: added an option `–disable-language-ietf` that causes mkvmerge to only write the legacy language elements.
  • mkvmerge, mkvpropedit, MKVToolNix GUI’s chapter editor: IETF BCP 47/RFC 5646 language tags in chapters: when reading XML chapter files the programs will now add “ChapLanguageIETF” elements for atoms that don’t contain them. The values are derived from existing “ChapterLanguage” elements.
  • mkvpropedit: IETF BCP 47/RFC 5646 language tags: setting/deleting the track language now acts on both the old language element as well as the “LanguageIETF” track header element.
    * mkvpropedit: IETF BCP 47/RFC 5646 language tags: added an option `–disable-language-ietf` that causes mkvpropedit to apply changes to the `language` track header property only to the legacy language track header element.
  • mkvinfo: IETF BCP 47/RFC 5646 language tags: added support for the “LanguageIETF” track header element.
  • MKVToolNix GUI: multiplexer: added full support for IETF BCP 47/RFC 5646 language tags for both track and chapter languages.
  • MKVToolNix GUI: chapter: added full support for IETF BCP 47/RFC 5646 language tags for chapter languages.
  • MKVToolNix GUI: header editor: added full support for IETF BCP 47/RFC 5646 language tags for track header languages. The header editor allows editing of the legacy language elements and the IETF BCP 47 language elements independent of each other.

Other new features and enhancements

  • mkvmerge: the chapter generation mode `when-appending` now also works with the splitting modes `parts:` & `parts-frames:` when using the `…,+…` syntax for appending other sections of the source file to the same destination file.
  • MKVToolNix GUI: multiplexer: the file selection dialogs now include the extension `.dtsma` for DTS files.
  • mkvmerge: MP4 reader: sped up parsing MP4 DASH files with a lot of segments (`trun` atoms) quite a bit.
  • The PCRE2 regular expression library is now used instead of `std::regex` for big performance improvements in all places where regular expressions are used for parsing big chunks of text, e.g. in the subtitle parsers.
  • all programs: Windows: all programs now support long file names on Windows 10 release 1604 if they’re turned on in the registry.

Bug fixes

  • MKVToolNix GUI: preferences: under certain conditions changing the selected entry in the page tree on the left did not cause the page shown on the right to be updated.
  • mkvmerge: splitting text by a fixed string (e.g. `,`) is now done by using `std::string.find()` instead of using a regular-expression-based text splitting function, greatly improving its performance.
  • mkvmerge: mkvmerge will now read-buffer file I/O when probing text file formats which increases its speed significantly on Windows.
  • mkvmerge: MP4 reader: fixed handling of `tkhd` atoms of version 1.

Build system changes

  • The PCRE2 library (the 8-bit variant) is now required.

Homepage –

Works on Microsoft Windows (both 32 and 64-bit versions), Apple macOS and Linux operating systems.

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