The legacy media player (k-player) pre-selected a subtitle language, whereas VideoJS does not, which could cause some viewers to not realize that subtitles for this media even exist.
Some times, when I played media on the legacy player, subtitles appeared without me expecting it. If they did not appear, I would have missed out on it.
It does do that. what language have you selected in your preferences and on which wiki was this specifically ?
Perhaps it has something to do with language fallback chain (like someone use en-GB while the subtitles are en).
On Commons, but happens on other wikis too. I have left my language preferences at the default so far, meaning it is English on Commons. I tested it with media files that have subtitles in several languages including English.
Why, is it expected that English captions don’t appear if someone’s UI language is set to British English or even Japanese? I think they should appear even then; actually foreign-language captions may be even more important than native-language ones: if one has only, say, en-2 knowledge (using Babel extension’s levels), they may not fully understand the spoken English text, but they may be able to follow the video if it’s captioned in English. Of course, if there are native-language captions available, they should be shown, but even English is better than nothing.
I didn't say it was expected, I said it might be a problem (that had been overlooked) and asking for confirmation if this was the situation that the user was in, to confirm that the correct problem had been identified.