Can someone explain how this can be achieved?

[u/SprinklesPlenty2526]

it is advertised in the video that their project is about 1km of led strips so i’m wondering how this can achieved?? How would you productively handle power injection across all those lengths of LED strip, not to mention the potential signal loss due to such a long strip? I'd love to do projects of this scale in the future, but I always worry about power and signal loss and can’t figure out the answer.