[dylan604]

>Surely modern compression can do better

I "surely" look forward to your Show HN write up on your new compression algorithm. We've been iteratively getting better at compression for some time now. It seems like everytime it looks like we've wrung every bit out of DCT, someone comes up with some a little more clever. Wavelets looked promising, but never took off.

>why does 480p upsampled ever look better than 1080p at the same bitrate

That's a very vague question. Are you stating that you think 480p upsampled to 1080p at 1.5Mbps looks better than a source at 1080p at 1.5Mbps? I have a hard time believing this to be true.

To understand why the chroma is sub-sampled and not the luminance has to do with how the cones/rods in the eyes work. There's a lot of things you can get away with (or trick if you will) the brain in what it is seeing. Is it better to lose half the height or half the width? Is it better loose more red than green or blue?