MKVToolnix 79.0 download the new version

In `mkvpropedit` it's called `alpha-mode`. mkvpropedit, MKVToolNix GUI's header editor: added support for the 'video alpha mode' track header property.mkvinfo: added support for the 'video alpha mode' track header element.alpha channel data in VP9 with a 'Block Addition ID' value of 1, which is also its default value. mkvmerge: added a new hack `always_write_block_add_ids` that can be used as a workaround for players that don't support the handling of missing 'Block Addition ID' sub-elements of 'Block More' elements in block additions properly.mkvmerge: file identification: the JSON identification output schema version has been bumped to 19.mkvmerge: MPEG transport stream reader: teletext subtitles intended for hearing impaired people (type 0x05) are now marked as such via the appropriate flag in the track headers.mkvmerge: Matroska reader: the file's timestamp scaling factor will be reported in JSON identification mode as the container property `timestamp_scale`.

mkvmerge: Matroska reader: the 'video alpha mode' track header property will be reported in JSON identification mode as the track property `alpha_mode`.mkvmerge: Matroska reader: the 'video alpha mode' track header property will be copied to the output file if present.

MKVToolnix 79.0 download the new version