Rendering Moving Pictures is Hard
In case you’re curious, here’s how television networks adapt between 60Hz and 50Hz feeds. Some networks just use frame repetition/dropping. However, higher quality television networks use fairly sophisticated equipment which analyzes the movement on screen, and attempts to deduce what frames a camera that was running at the target framerate would have recorded. With such a system, pretty much everything you see is a fiction – something the frame rate converter thinks is a pretty good approximation to the original moving image. And most of the time it works pretty well – a lot better than simply dropping or duplicating frames.