All of that stuff should be handled through standard APIs. Applications shouldn’t be updating themselves at all; that’s the job of the operating system’s package manager.

Really, a video player should be a dumb bit of glue code that wires together file open APIs with video playback APIs, and a few bits and bobs for saving preferences (API) and allowing remote control (another API). There’s no reason whatsoever for a video player to be able to access files arbitrarily or connect to the internet or log keystrokes in the background or anything else! The only reason they can do this is because we haven’t built operating systems with all this in mind, apart from mobile OS’s that is.