The VideoLAN Forums

VLC 3.0.14 does not seem to accept formatting changes in the way that it displays subtitles (closed caption). The opacity slider does absolutely nothing, the font selection does nothing, the font size does not change regardless of the selection, and only the subtitle background color changes based on the user selection.

Let's enable those apparent functions!

This is probably my biggest complaint with VLC. If this could get fixed I'd be delighted.

It works for me with text subtitles (e.g.: .SRT). Changing font also works after you exit and restart VLC, but not on the fly.
But if your subtitles are bitmap images based (e.g.: DVD or BD subtitles) then it obviously won't work.