There's no wiper here and no coating. There's a disc of clear glass spinning in front of the lens fast enough that a raindrop never gets the chance to land.
Spin a glass disc at 3,000 RPM and it's turning 50 times a second. A drop that hits near the edge gets thrown with roughly 500 times the force of gravity, far more than the surface tension holding it together. The shear from the moving glass tears it into mist before it can even form a bead.
The only drop that survives sits dead center, on the axis, where the tangential speed falls to zero. That one stays too small to register on screen, so the picture reads as clean.
Snow is lighter and the centrifugal throw alone sometimes misses it, so the same rotation pulls a thin vacuum across the surface and lifts the flakes off. Rain gets flung, snow gets sucked away. Nothing builds up.
The hard part was never the spinning. It was spinning that fast with zero wobble. Any imbalance at 3,000 RPM turns into a vibration the camera reads as blur, and the second the operator pans, an unbalanced disc fights back with gyroscopic force. The glass has to be balanced to a tolerance most machine shops can't hit.
The trick is over a century old. Two British engineers patented it in 1917 for ships, so pilots could see through spray and sleet without a wiper arm cutting across the windscreen. The same idea that let a ship's crew read a storm in 1917 is why you can watch a race through a whiteout today.
People Of The Internet (@PeopleOfTheInt)
Even during heavy rain they broadcast crystal clear footage 🔥
Video
— https://nitter.net/PeopleOfTheInt/status/2071150358412558764#m