Change the font in OSD/SUbtitles preferences.
I also solved thanks to this. I always use UTF-8 for my files and i expected that would be enough.
More details: you have to set a font that allows Japanese, for example, I had Arial and it doesn't support Japanese. Now i choosen MS Gothic and it is fine. I suppose that with other alphabets i should change again.
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Wouldn't be possible to have a message error? Like a popup: "Language not supported by the current font (Arial) please choose another font".
Or at least in OSD/Subtitles could be a small explanation Subtitles Effect >> Font (in case you don't see the subtitles for some non-latin alphabet, ensure that the file is in UTF-8 and then choose a valid font for this language).
Other option could be, that VLC automatically select another encoding if the default one doesn't contain the current language.
It's not for complaining, but just i lost a lot of time before reading this thread. And during my searches i noticed how many people have the same problem every day, but their error is not to write/search in this forum but in other ones.
Thanks