I'm planning to encode some of my blu-ray discs to AV1 with maximum quality in mind. After thinking I had a good set of settings nailed down, I got sensitized to the topic of banding and found that in certain frames, my encodes were suffering from it quite badly.
I also found the biggest magnet for banding in an animated show: the very first episodes of "The Eminence in Shadow" shows a purple blanket that has crazy banding even at 10-bit with high bit rates.
Here's aom-av1-lavish, the "opmox mainline merge" branch as of November, 14th, 2023 with --arnr-strength=0 --enable-dnl-denoising=0 --denoise-noise-level=1
After seeing that another (x265) encode did it much better and even SVT-AV1 with mostly default settings performed well (see further down), I changed to --arnr-strength=1 --enable-dnl-denoising=0 --denoise-noise-level=6 and what a difference:
Finally, this is the result of SVT-AV1-psy as of January, 22nd, 2024. The settings are --film-grain 6 --film-grain-denoise 0:
So how does one estimate a video's noise / grain level? Do I just develop a feel for which setting corresponds to what look? That might involve quite a bunch of failed encodes, however.