I don't understand, why is this ruled out? Assuming that phones reach a point where this is computationally cheap, what would be so hard about having a sliding window for each frame in the video?
Nothing prevents that, but if there is a lot of movement (which would be the point of using video) then the great results aren’t as easy to get. You can’t take a still of someone dancing in a dark room with an iPhone, you can take a still of someone standing reasonably still in a dark room.
Isn't this a similar problem to the blurry-face vs. leaf-face issue discussed? If yes, then one would hand it off to computation to figure out which parts matter and need doctoring, except scaled up to video.
The camera moving?
Then increase the rate at which frames get captured since the video is destined to be ≈24-30 fps anyway?
But the higher the framerate, the less time you have for exposure on each frame.