Hi, @richgel999. Thanks for the great compressor and your work along the years.

This issue isn't something new, because AMD Compressonator suffers from the exact same artifacts, and I know some kind of degradation is to be expected. There are format limitations and the RGB part may be eating all the bits.

I find it interesting that, while lower quality, using an older BC3 compressor produces a much more coherent image. Because I don't know if this is an isolated/edge case I figured bringing it up and posting actual samples would help. ¯\_(ツ)_/¯

Here's bc7enc's unpacked alpha:

Here's the result on a white background:

Here are the AMD Compressonator 4.0.4855 results, with their staircasing counterparts:

Or, who knows, maybe I'm using it wrong. The problem doesn't look that ugly on a gray or checkerboard background, but it's really apparent against bright and contrasty gradients.

Between the curve, the sudden color and alpha changes and all the noise these logos may be a tough case. On my end of the content pipeline I think they'll have to live uncompressed for now. They don't pass the quality check.