tree 4bafbf9a1f55c2c81dcfae07c0d7d40026cb44ef
parent 80070c4b32205c8140677afa10009c4eee911daa
author Julio Barba <juliobbv@gmail.com> 1732144730 -0500
committer Julio Barba <juliobbv@gmail.com> 1732144730 -0500

Tweak 4:4:4 chroma QM levels with `tune=ssimulacra2`

At the same level, chroma QMs are flatter in 4:4:4 chroma subsampling
mode relative to 4:2:0, so this commit introduces a formula that picks
a chroma QM level for a given frame qindex when encoding 4:4:4 content.

Approximate BD-Rate gains over no chroma QM adjustment - cpu-used=6
(Daala's subset1):
- SSIMULACRA2 60: -0.3%
- SSIMULACRA2 70: -0.6%
- SSIMULACRA2 80: -0.5%
- SSIMULACRA2 90: -0.4%

Bug: aomedia:375221136
Change-Id: I358e2701e327520583107aa860eae80fe32f2d1a