Hipix and JPEG-XR are both very bad. I wonder if the JPEG-XR encoder I'm using could be less than the best? If someone knows a reference to the best command line windows JPEG-XR encoder, please post it. The one I'm using is from some Microsoft HD-Photo SDK distribution.
It's interesting to see how the different encoders do on the different metrics. x264, webp and kakadu are all identical under MyDctDelta. Kakadu falls down in SSIM, but does much better on SCIELAB. This tells you that kakadu is not preserving local detail characteristics as well, but is preserving smooth overall DC levels much better.