Hacker News Reader

720p isn't half 1080p, it's a quarter because you're halving resolution on both axes.

1080p is 1920x1080 ~= 2.1m pixels versus 1280x720 = 921,600 .

So a little less than half but definitely not a quarter. And neither dimension is actually halved.

:facepalm: I rushed to be wrong by not mentaly checking that 720 is indeed half 1080. Resolutions indeed never doubled from one step to the next.