JPEG XL is about one image codec generation ahead of HEIF and AVIF in my own experiments and personal evaluations. Butteraugli, an objective metric I developed originally for guetzli, during 2014 to 2022, also agrees with this evaluation, as well as the large-scale human rater study by cloudinary.
Many objective metrics get really confused about JPEG XL as it uses some pretty advanced psychovisual modeling that is not implemented in usual metrics.
The best metrics to try in my opinion are butteraugli, ssimulacra 2 and -- with some reservations -- dssim.
Many objective metrics get really confused about JPEG XL as it uses some pretty advanced psychovisual modeling that is not implemented in usual metrics.
The best metrics to try in my opinion are butteraugli, ssimulacra 2 and -- with some reservations -- dssim.