The HDMI standards are a mess. HDMI 2.1, in particular, is a uniquely frustrating mess, with haphazard support among TV manufacturers, cable makers, and devices that make setting up, say 120Hz gaming on a PS5 or Xbox Series X a uniquely harrowing experience. ...
Let’s start with the good: HDMI 2.1a is an upcoming revision to the HDMI 2.1 stack and adds a major new feature, Source-Based Tone Mapping, or SBTM. SBTM is a new HDR feature that offloads some of the HDR tone mapping to the content source (like your computer or set-top box) alongside the tone mapping that your TV or monitor is doing. ...
Now here’s the bad: like every other unique HDMI 2.1 feature, including variable refresh rates, automatic low latency connections, and the bandwidth necessary to offer things like 10K resolution or 120Hz refresh rates, SBTM will be an optional feature that manufacturers can support — but not something that they’re required to support. ...
See the full story here: https://www.theverge.com/2021/12/29/22856103/hdmi-2-1a-spec-standard-mess-cables-source-based-tone-mapping-ces-2022