I have a VOB from Kill Bill Vol 1 for chapter 12. This is a good chapter to test regular subtitles versus forced.
On the subtitle tab in Handbrake, for Track, select Foreign Audio Search. When you select it, Forced Only and Burned In will be checked. If forced subtitles are detected, they will be burned in (no turning on in aTV menu).
Checkboxes: Forced Only, Burned In, Default. Forced Subtitles can be captured and burned into the source video. HandBrake can scan the source for subtitles that appear only 10% (or less) of the time in addition to scanning for the presence of any forced subtitles.
These are not burned into the video unless you choose to do so however you can only burn 1 subtitle track into the file.
Garth Marenghi's Darkplace Cz Subtitles.
Again remember this trick only works with encoders that use the splitter. Using my avatar subtitles as an example, if you wanted to burn in only the NAvi.
In Handbrake, I have the subtitles tab, add track English PGS, and nothing checked (no forced only, no burn in, no PGS). But when I convert, I see subtitles burned in. If I remove the subtitle in Handbrake, then there's no burned in subs or option to turn them on.
...that is used to define subtitles "burned" into for e.g. a mkv hence they usually called "forced"
On the subtitle tab in Handbrake, for Track, select Foreign Audio Search. When you select it, Forced Only and Burned In will be checked.
What's video with burnt-in subtitles. Picture-based subtitles (from DVD/Blu-ray rip). Subtitles text-file (from Movie/TV web sites).