Investigating using YCbCr color space for perceptual errors

[solidpixel]

We currently have a very basic perceptual heuristic based on static channel weighting. It's not gamma corrected for linear textures either.

The bc7enc compressor evaluates errors in YCbCr color space which gives higher quality perceptual results, at the expense of a higher compression cost. Review and see if it's worth the added overhead.

[aras-p]

IIRC Rich also mentioned somewhere that he played around with OkLab colorspace too (which was invented after bc7enc happened), and that the results were better (for some definition of better). But OkLab is more costly to evaluate than YCbCr, without finding some ways of speeding that up.