The HDMI Forum has announced that at CES 2022 starting January 4 in Las Vegas, they will introduce HDMI 2.1a. This is not a simplification of the protocol, of which we already saw that 2.1 does not mean that it meets all the requirements, which makes it difficult to know all the options that a cable, television or multimedia player will give us.
Learn about HDMI generations
HDMI 2.1a is an upcoming revision of HDMI 2.1 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 along with the tone mapping performed by the TV or monitor.
HDMI 2.1a will expand over HDMI 2.1
SBTM is not a new HDR standard, rather it has been made to help existing HDR setups work better by better optimizing the content that passes to the screen or by eliminating the need for the user to manually calibrate their displays for HDR.
The HDMI Forum notes that it will be possible for manufacturers of set-top boxes, games and televisions to add support for HDMI 2.1a and its source-based tone mapping through firmware updates depending on their design. But very surely that is not applied by updating firmware for a monitor or television, but by buying a new one that already includes it as standard. Also, as with all other HDMI 2.1 exclusive features, SBTM will be an optional feature that manufacturers will be able to support, but not something that they need to support.
According to the HDMI License Manager, now that the HDMI 2.1 standard exists, the HDMI 2.0 standard no longer exists and all new HDMI 2.0 ports must be grouped under the HDMI 2.1 brand, despite not using any of the new features included in the new standard 2.1. HDMI 2.1a will work in a similar way, so all the new ports will, in theory, be labeled HDMI 2.1a, but they will not have to offer the new SBTM or any of the features of HDMI 2.1.
Source: The Verge
