box around hardcoded subtitles

[qaqaqaq]

Is there a way to have a black or transparent box around already hardcoded subtitles? serving as a filter of some sorts. Just to make them more visible.

[jagabo]

Generally, no. In some cases (where the subs have characteristics that make them easily distinguished from the background) you might be able to use some advanced AviSynth filtering. But it most likely won't be perfect.

[lingyi]

Would it be possible to create removable subs with a solid background in a box? Or if you can figure out the exact font and size of the original subs, create new removable subs that would overlay over the existing subs.