Comment by techjamie

Personal guess based on the impression I get from my parents' TV: You know how when you pause video while something is moving quickly, that object is blurred in the frame? Motion smoothing has that to work with, and causes the blur to persist longer than it should, which is why it looks bizarre - you're seeing motion blurs for larger movements than what's actually happening. Like the object should have moved twice the distance for the amount of blur, but it didn't. Something recorded and replayed at a high framerate wouldn't have this problem.

The motion smoother also has to guess which parts of the picture to modify. Is the quarterback throwing the ball the important part? The team on the sidelines? The people in the stands? The camera on wires zooming around over the field to get bird’s eye views? When it guesses wrong and enhances the wrong thing, it looks weird.

Also imagine the hand of a clock rotating at 5 minutes’ worth of angle per frame, and 1 frame per second. If you watched that series of pictures, your brain might still fill in that the hand is moving in a circle every 12 seconds.

Now imagine smoothing synthesizing an extra 59 frames per second. If it’s only consider the change between 2 frames, it might show a bright spot moving in a straight line between the 12 and 1 position, then 1 and 2, and so on. Instead of a circle, the circle of the hand would be tracing a dodecagon. That’s fine, but it’s not how your brain knows clocks are supposed to move.

Motion smoothing tries to do its best to generate extra detail that doesn’t exist and we’re a long way from the tech existing for a TV to be able to do that well in realtime. Until then, it’s going to be weird and unnatural.

Film shot at 60FPS? Sure. Shot at 24 and slopped up to 60? Nah, I’ll pass.