Forced flag in subtitles broken? Using MKVToolnix doesn't he

[patron]

Hey,

I'm using MakeMKV for KODI to rip BDs as MKVs. This works such good that I even use it for Blurays I seldom watch, because watching blurays on the pc is a pain without ripping them first.

BUT there is something that recently got my attention:
MKV doesn't seem to rip the forced subtitles perfectly

TL;DR

I used MKVToolnix (Header editor) to set the forced subtitle as "forced = yes", so KODI - refeering to several forum posts and the wiki - has to play them even without me enabling subtitles.
I did already set the default languages of KODI to the forced subtitlte languages.

But it doesn't work.

How can you change this flag correctly?

[Woodstock]

From what I've been able to determine (and Mike and others will correct me if this is wrong), MakeMKV does just two things with subtitle tracks...

1. In the case of PGS subtitles, it will optionally compress them with zlib for compatibility with some players (WDTV profile).

2. By default, it will offer to copy any subtitles that are flagged as "forced" in a subtitle track to a separate, forced-only (FO) track. If subtitles are marked as "forced", they'll be marked as forced in the forced-only track, but... if there is no forced flag, the created FO track will be remove

Otherwise, it copies the original through to the MKV file.

As for "default" and "forced" flags, I don't know if it sets those. I would expect that the "forced only" track it creates, assuming it is not empty, isn't treated as "special", because it isn't original.

MKVtoolnix will let you set these, as you mentioned. You can configure default selection rules for MakeMKV to give particular languages listed first for audio and subtitle tracks, but they do not change flags.

[Chetwood]

From the default.mmcp.xml:

setFirstSubtitleTrackAsDefault="true"
setFirstForcedSubtitleTrackAsDefault="true"

[Krawk]

Has the "forced" flag been documented in the MKV SDK? If so and someone can point me the right direction, I would be grateful.