Comment by BlueTemplar
5 years ago
That's a bit like saying that we shouldn't use lossy image/video compression.
Do you realize the amount of 'waste' that a 32bpc†, 4:4:4, imaginary color triangle gamut picture would have ?
†it looks like the human eye has a sensitivity of 9 orders of magnitude, with roughly 1% discrimination (so add 2 orders of magnitude). So, looks like you would need at least 37 bits per color with a linear coding, the overwhelming majority of which would be horribly wasted !
I have no issue with lossy compression; but things like 4:2:0 aren't really typical lossy compression. It's like calling resizing an image to half its resolution "compression".
Also lossless compression can reduce plenty of "wasted" bits already (see: png vs bmp).
But they are ! Like other lossy forms of compression, chroma subsampling takes advantage of the human visual system's lower acuity for color differences than for luminance.