Please help me understand subtitle parameters

[pimpsuit]

When I choose what elements from a Blu-Ray that I want to include in an MKV, MakeMKV (usually) shows me a list item for "Subtitles English" and then a subitem for "Subtitles English (forced only)". See the image below for an example.

Does this indicate 2 different subtitle tracks? If so, why do I only get one track in the MKV? If I only get one standard subtitle track, does that mean that the forced subtitle track is empty?

If I want only the forced subtitles in my MKV, can I uncheck the "Subtitles English" box and leave the "Subtitles English (forced only)" checked? Or do I have to leave both boxes checked?

Sorry if this is obvious stuff, but for some reason I just cannot get my head around it.

[ndjamena]

PGS subtitles on blu ray can have forced flags attached to certain elements. The Matroska format has no equivalent so it is necessary to separate the forced subtitles from the stream. Those Forced subtitles are put in the "forced" track, if MakeMKV finishes processing the title and has found no forced elements it will remove the forced track from the track header.

If I want only the forced subtitles in my MKV, can I uncheck the "Subtitles English" box and leave the "Subtitles English (forced only)" checked?

Yes.

[pimpsuit]

Thanks for the explanation. That helps me understand.