Log Message:
mkvtoolnix: updated to 58.0.0

Version 58.0.0 "Supper's Ready" 2021-06-13

New features and enhancements

* mkvmerge, MKVToolNix GUI's multiplexer: the handling of the "default \ 
track"
  flag has been changed to match the recent changes to the Matroska
  specifications. The new semantics are that if it is set, it is supposed to
  signal to the player that this track is eligible for being played by
  default, potentially taking other factors such as user preferences regarding
  languages into account.

  This implies that more than one track of each type can have this flag
  set. For example, a Blu-ray disc with three audio tracks might have
  the main audio in both English and Japanese, whereas the third audio
  track contains the director's comments. In such a case the first two
  tracks should have the "default track" flag set, the third one
  shouldn't.

  Earlier `mkvmerge` was enforcing that only one track of each type could have
  the flag set. This restriction has been removed, both in `mkvmerge` and in
  the GUI's multiplexer.

  `mkvpropedit` and the GUI's header editor are unaffected as they've always
  allowed to set the flag on as many tracks as the user wanted.
* mkvmerge: AVC/H.264 & HEVC/H.265 identification: added the stream's pixel
  dimensions (AVC only; were present for HEVC already) & default
  duration.
* mkvmerge, mkvextract: HEVC/H.265: added support for reading single-layer
  Dolby Vision from Annex B type bitstreams (elementary streams, MPEG
  transport streams). Patch by quietvoid.
* mkvinfo: the option `-X`/`--full-hexdump` now affects all binary elements,
  not just the frame data in `SimpleBlock` and `BlockGroup` elements.
* MKVToolNix GUI: multiplexer: the "delay" and "sync" \ 
options can now be used
  for chapters in source files, too.
* MKVToolNix GUI: when moving list entries up & down with the optional buttons
  or the keyboard shortcuts (instead of using drag & drop), the GUI ensures
  that the top-most selected entry remains visible after the move.
* MKVToolNix GUI: added an option in the preference to use legacy MIME types
  for font attachments instead of the current standard ones
  (e.g. 'application/x-truetype-font' instead of 'font/sfnt' and 'font/ttf').

Bug fixes

* build system: fixed filtering out optimization options when compiling the
  file `iso639_language_list.cpp` (before only numeric optimization levels
  were filtered out and only if it wasn't the last option in the list of
  flags).
* build system: when libmagic was detected via `pkg-config`, MKVToolNix was
  actually compiled without support for libmagic due to a preprocessor symbol
  not being defined.
* mkvmerge: MP4 reader: fixed an issue with timestamps overflowing when the
  file's or the track's time scale is large.
* mkvmerge, mkvextract: fixed key frame handling for `BlockGroup` elements
  with a forward reference but no backward references. Patches by Tom Yan.
* mkvmerge, mkvpropedit, MKVToolNix GUI's chapter editor: the programs will no
  longer omit writing mandatory elements set to their default value if other
  elements of the same type are present in the same master. This affects
  mostly the "chapter language" element which may occur multiple times \ 
within
  the same "chapter display" master. If it does occur multiple times \ 
and one
  of them is set to "English" (which is that element's default value), that
  element will now be written, too.
* mkvmerge, mkvpropedit, MKVToolNix GUI's chapter editor: when parsing chapter
  files IETF & legacy language elements as well as legacy country elements
  will now be properly generated depending on which exist already, especially
  when there's more than one language and/or country element in a "chapter
  display" element.
* mkvmerge, mkvpropedit, MKVToolNix GUI's chapter editor: fixed reading
  OGM-style chapter files with timestamps that don't have exactly three
  decimal places. Any number of decimal places between one and nine is now
  supported for nanosecond precision.
* MKVToolNix GUI: chapter editor: added/fixed support for "chapter display"
  elements with multiple languages or countries.

Build system changes

* Qt 6: added support for building with Qt 6. `configure` will look for Qt 6
  first and only continue looking for Qt 5 if Qt 6 isn't found or disabled via
  `--disable-qt6`.

  Qt 6 detection works by first looking for the `qmake6` binary. Its location
  can be specified with the `--with-qmake6=…` option.

  All other Qt 6 related facts (such as compiler & linker flags or the
  position of the other required tools such as `lconvert`, `moc`, `rcc` and
  `uic`) will be derived from the output generated by `qmake6`.

  Note that at this point Qt 6 is not yet supported for the cross-compilation
  build to Windows, nor is a static Qt 6 build supported yet.

  Note that the command line options `--enable-static-qt`,
  `--with-qt-pkg-config-modules` and `--without-qt-pkg-config` only apply to
  the Qt 5 and have no effect on Qt 6.
* Qt 5: the options for specifying the position of the tools (`--with-moc=…`,
  `--with-rcc=…` and `--with-uic=…`) have been removed. Their position will
  now be derived from the output generated by `qmake`.
* `configure`: completely disabling the GUI now requires passing both
  `--disable-qt6` and `--disable-qt` options.
* Boost's multi-precision library is now required.
* Boost v1.66 or newer is now required.

Other changes

* The Windows build is now using an updated version of the
  `file`/`magic` library for MIME type detection of attachments. This
  affects fonts whose MIME types will now be the current standard MIME
  types (e.g. `font/sfnt` or `font/ttf` for TrueType fonts). As this
  might pose problematic with older players that only support the
  legacy MIME type (e.g. `application/x-truetype-font`), a new option
  was added in the GUI's preferences to use the legacy MIME types
  instead of the current standard ones. This is off by default.
  Builds for other operating systems have already been using newer
  versions of the `file`/`magic` library for a long time.