alt Hacker NewsI can vouch for GP's exact experience. Facetime does feel much smoother than other videocalling apps for Aus<>Europe. Of course they don't run their own fiber network. The good engineering is making it feel smooth and good despite that. At its core, nothing about computing is smooth. Everything is based on making it feel that way, using countless techniques.
What "techniques"? Audio/video over high-latency connection is not a computer game where there all all kinds of latency compensation techniques - several meeting participants start speaking at the same time, realize they do only after RTT, stop, then awkwardly wait for a moment and repeat hoping for no "collision", rinse-repeat. Everyone who often has meetings with participants connecting from different continents knows what I'm talking about. But you can have this in beautiful high-definition "smooth" 4K if bandwidth is high enough, yes.