## Important notes
* Feature removal: several deprecated features have been removed:
* mkvmerge: the deprecated options `–identify-verbose` (and its counterpart
`-I`), `–identify-for-gui`, `–identify-for-mmg` and
`–identification-format verbose-text`
* all command line tools: support for the deprecated, old, proprietary format
used for option files
* all command line tools: support for passing command line options via the
deprecated environment variables `MKVTOOLNIX_OPTIONS`, `MKVEXTRACT_OPTIONS`,
`MKVINFO_OPTIONS`, `MKVMERGE_OPTIONS` and `MKVPROPEDIT_OPTIONS`
* mkvinfo: most of its code was re-written in order to lay the groundwork for
including its functionality in MKVToolNix GUI but with more features than
the existing mkvinfo GUI. The result is that a lot of its output has been
changed slightly while keeping the basic layout. Changes include but aren’t
limited to:
* Several element names are a bit clearer (e.g. `Maximum cache` instead of
`MaxCache`).
* All timestamps and durations are now output as nanoseconds in formatted
form (e.g. `01:23:45.67890123`). All additional formats (e.g. floating
point numbers output in seconds or milliseconds) were removed.
* Element names for chapters and tags are now translated if a translation is
available.
* Elements located in wrong positions within the Matroska document are
handled better.
While mkvinfo’s output is mostly kept very stable, it is not designed to be
parsed by other utilities. Even though I’ve tried hard to cram all changes
and cleanups into this version, additional changes may be made in the next
couple of releases depending on user feedback and bug reports.
## New features and enhancements
* mkvmerge: AVC/h.264 packetizer (framed): access unit delimiter NALUs will
now be removed. Implements #2173.
## Bug fixes
* mkvmerge: AVC/h.264 parser: when fixing the bitstream timing information
mkvmerge will now use exact representations of the desired field duration if
possible. For example, when indicating 50 fields/second `num_units_in_tick`
is set to 1 and `time_scale` to 50 instead of 5368709 and 268435456. Part of
the fix for #1673.
* mkvmerge: AVC/h.264 parser: mkvmerge no longer assumes that encountering
sequence parameter set or picture parameter set NALUs signal the start of a
new frame. Fixes #2179.
* mkvmerge: AVC/h.264 packetizer (framed): when mkvmerge is told to fix the
bitstream timing information, it will now update all SPS NALUs, not just the
ones in the AVCC. Part of the fix for #1673.
* mkvmerge: MPEG TS reader: TS packet payloads will only be treated as PES
packets if the payload actually starts with a PES start code. The prior
behavior led to wrong timestamps and potentially broken frame data. Fixes
#2193.
* mkvmerge: MPEG TS reader: mkvmerge will now drop incomplete PES packets as
soon as an error is detected in the transport stream instead of passing the
incomplete frame to the packetizer. An error is assumed either if the
`transport_error_indicator` flag is set or if the value of the
`continuity_counter` header field doesn’t match the expected value. Fixes
#2181.
* mkvmerge: Opus: when re-muxing Opus from Matroska mkvmerge will now write
„block duration“ elements for all block groups where a „discard padding“ is
set, too. Fixes #2188.
* mkvmerge: SRT reader: mkvmerge can now handle SRT files with timestamps
without decimal places (e.g. `00:01:15` instead of `00:01:15.000`).
* mkvmerge: read buffer I/O class: the class could get out of sync regarding
the file position of the underlying file I/O class causing wrong data to be
returned on subsequent read operations. One result was that trying to
identifying MPLS files that refer to very short M2TS files caused mkvmerge
to segfault.
* mkvmerge: multiplexer core: if there’s a gap in audio timestamps, a new
block group/lace will be started for the first frame after each gap. Before
the fix the frame after the gap was often stored in the previous block group
causing the gap to be in the wrong place: at the end of that block
group. Fixes #1700.
* mkvextract: AVC/h.264: if two consecutive IDR frames with the same
`idr_pic_id` parameter and no access unit delimiters are found between them,
mkvextract will insert an access unit delimiter in order to signal the start
of a new access unit. Fixes #1704.
* MKVToolNix GUI: update check dialog: Markdown links will now be converted to
clickable links. Fixes #2176.
* build system: fixed a race condition when creating new directories if `rake`
is run with `-jN` in newer versions of Ruby/`rake`. Fixes #2194.
## Build system changes
* [cmark](
https://github.com/commonmark/cmark), the CommonMark parsing and
rendering library in C, is now required when building the GUIs.
