It’s often impossible to read plex subtitles, it doesn’t have basic features like having a dark background behind the subtitles or control over the size, which often leads to the subtitles being too small or too big.
backgrounds are really important though, anyone who watches content from a different language should understand the pain of trying to read subtitles that are overlaid on top of some other languages text. Simply having the option to have dark backgrounds like generally every subtitle system ever allows you to do would fix a lot of problems. people have been asking for this for years and years.
I rarely use subtitles, but my daughter -in-law and granddaughter use them all of the time and I have heard them mention the problem. Often, there is text on the screen, like in the mock-up I’ve done here that is part of the film. In this example, “Meanwhile, back at the ranch…” is part of the film, you can’t turn it off, but someone has “got a table ready” Yeah, both are in English here, but it gives an example.
So, what I think the OP is talking about is a background similar to Closed Captions on TV/DVD, or the way they appear on a Roku if you have “soft” subtitles enabled. There’s an opaque box around the subtitles, so they are a little more prominent (the bottom half of the mock-up) Quite a few video players give an option for the border style as either “Outline” (like Plex has) or “Opaque Box”
It happens more often than you would think - it can be hard coded subs for foreign language parts, a description of location, etc.
