Please add the ability to translate subtitles available on Wikipedia or Wikimedia Commons; For example, translate English subtitles to Persian subtitles, etc. using the button in the video player subtitles section.
Topic on Extension talk:TimedMediaHandler/VideoJS Player
This is already available. For example, on https://commons.wikimedia.org/wiki/File:The_Big_Parade.webm which is today's Media of the Day, click the subtitles button ("CC" if en-us, otherwise a white box with some lines), then click "create captions" (in en-us; in en-gb, "subtitles", in fa, "ایجاد زیرنویس") which takes you to the subtitle creation system.
I mean, translating subtitles into another language using Wikipedia's content translation capabilities.
Ah, right. That proposal is T44495; I'm pretty confident it's never going to happen using the current technology stack, sorry.