5.951 bits/texel, 45.1 dB, 75773 PSNR/bpt
I used astcenc to generate a .astc file, loaded it into memory, then used the code in ert.cpp/.h with a custom callback that decodes ASTC blocks. All the magic is in the ERT. Here's a match injection histogram - this works: 1477,466,284,382,265,398,199,109,110,87,82,105,193,3843
These RDO ASTC encodes do not have any ultra-smooth block handling, because it's just something I put together in 15 minutes. If you look at the planet you can see the artifacts that are worse than they should be.
Next are larger blocks.