Status Firefox support WEBVTT subtitles?

[Kingdaddy 2]

I'm dying trying to find discussion regarding subtitles. So far dates
newer than 2015 I have not found. The default text style is unworkable
for me on computer screen, probably great for a smartphone. (Very large,
white text on black background).

Where can I find current information and/or status.

Carl

[Kingdaddy 2]

Well... I did not answer the question, but I did discover it is not a
"down level' browser that was causing my inability to get "expected
results".

When I used a utility to convert SRT file to VTT file, text style no
longer worked. I had trouble finding help in ancient discussions.

I did find help here;
https://w3c.github.io/webvtt/#styling

Carl

[VanguardLH]

https://developer.mozilla.org/en-US/docs/Web/API/WebVTT_API
https://www.w3.org/TR/webvtt1/

Looks like CSS is used to define styling of the subtitles. So what you
get depends on what the site delivers which may depend on how you
configure your account there (i.e., options, if any, to define size,
color, background, etc).

https://en.wikipedia.org/wiki/WebVTT

>From the chart there, looks like Firefox supports WebVTT but not CSS
Styling for WebVTT. Google Chrome does, though. However, the following
article mentions styling (but not in which versions of Firefox it is
supported):

https://developer.mozilla.org/en-US/Apps/Fundamentals/Audio_and_video_delivery/Adding_captions_and_subtitles_to_HTML5_video

It mentions the media.webvtt.enabled setting in about:config but in my
FF 56 there is no such setting defined. If I seach on just "webvtt",
there are a couple of settings but not an on/off toggle.