EXR DWAA and DWAB are conceptually similar to lossy JPG compression,
with a tunable file size vs image quality parameter. However, previously
Blender always used the fixed default setting, which is kinda similar
to very high quality (like 97) for JPG.
Internally EXR DWA/DWB quality parameter is inverted scale, i.e. 0 is
best/lossless quality, and increased setting value means decreased
quality. However the rest of Blender UI uses 1-100 JPG-like quality
scale, where values above 90 are "visually lossless", 100 is lossless,
and going below something like 50 would be visually quite lossy. So map
that to internal DWA setting:
- blender 100 -> DWA 0
- blender 97 -> DWA 45
The rest is linear relation based on those two points.
Pull Request: https://projects.blender.org/blender/blender/pulls/128790
8b275092e0