MKVToolNix 81.0.0 (64-bit)

What's new in this version:

New features and enhancements:
- mkvmerge: MPEG transport stream reader: HEVC/H.265: added support for reading single-layer Dolby Vision from Annex B type bitstream read from MPEG transport streams. Partially implements #3113.
- mkvmerge: MPEG transport stream reader, HEVC/H.265 elementary stream reader: added support for reading dual-layer Dolby Vision with both the base & enhancement layers in the same track from Annex B type bitstreams in MPEG transport files & elementary stream files. Implements #3126.
- mkvmerge: MPEG transport stream reader: HEVC/H.265: implemented combining dual-layer Dolby Vision with base & enhancement layers in different tracks. Implements #3127.
- MKVToolNix GUI: multiplexer: added a new option in the preferences for always enabling 'forced' subtitle tracks. A subtitle track is considered to be 'forced' if: the corresponding property is set in the source file; the track's name contains the word 'forced' (in English); deriving the 'forced display' flag from file names is active & the file name matches the corresponding pattern. The option is disabled by default. Implements #3627.
- MKVToolNix GUI: multiplexer: the functionality for detecting file name sequences when adding files can now recognize the patterns used by GoPro's cameras for chaptered video files. Implements #3633.
- xyzvc_dump: the end position of the current NALU will be output in non-portable format as well.
- xyzvc_dump: HEVC: the tool will now also output the inner NALU type of Dolby Vision NALUs (`unspec62` and `unspec63`).

Fixed:
- mkvmerge: when the user requests processing be stopped after the video ends
- mkvmerge` will now take appending files into account properly. It won't stop processing unconditionally after the first file ends anymore. Fixes 3618.
- mkvmerge: AV1 handling in readers: the readers will now provide the pixel dimensions to the AV1 packetizer as early as possible, just like for other video packetizers. That way the pixel dimensions are available for calculating the display dimensions when command-line options such as aspect-ratio` & `--aspect-ratio-factor` are used. Before the change the calculation was done based on initial pixel dimension values of 0x0, resulting in display dimensions of 0x0, too. Fixes #3611.
- mkvmerge: HEVC/H.265 packetizer: when reading & appending HEVC/H.265 from Matroska, MP4/MOV or FLV files the first frame of all the appended files was sometimes dropped, resulting in broken video at the point where video is appended. Fixes #3479.
- mkvmerge: MPEG transport stream reader: when reading MPEG transport streams from Blu-rays the four-byte long `TP_extra_header` structure in front of the transport packets are now skipped properly. Before the fix a stray byte with value of `0x47` inside that `TP_extra_header` structure could have thrown off the detection of where the transport packets start, leading to mkvmerge dropping a few audio and/or video frames at the start of the file. Fixes 3632.
- mkvextract: AAC extractor: when an invalid program config element in the GA-specific config element is encountered, the program config element will be disregarded, which avoids mkvextract aborting with an exception. Fixes 3606.
- xyzvc_dump: fixed the tool aborting with an exception when the last NALU in an Annex B type file was shorter than four bytes.

Other changes:
- AVC & HEVC dumper development tool: the tool has been renamed from xvc_dump` to `xyzvc_dump` as `xvc` is an abbreviation for an existing video codec (Extreme Video Coding), and the tool has nothing to do with that codec.