WebVTT Subtitle Support

[sturmen]

I saw your comment on #53 about WebVTT not being supported, but in my experience subtitles are supported in browsers. ffmpeg support for webvtt is a pretty mature at this point so would you reconsider adding support in boram?

[Kagami]

Browsers don't support internal WebVTT subtitle tracks (i.e. as a part of a single file). Subtitle track can be added only via additional .vtt file.

[sturmen]

That's a shame. In what is almost certainly the most niche use case imaginable: my Galaxy S9 actually supports WebVTT subtitles as a track in the WebM container with the system default media player, so there's that.