HDMI standard license 'HDMI 2.1a' announced, what is the newly added function 'SBTM'?

At the virtual press briefing held ahead of CES 2022, the world's largest consumer electronics trade fair, the HDMI Forum, which develops the HDMI standard, announced that it will update the HDMI standard certification scheme from the conventional HDMI 2.1 to 'HDMI 2.1a'. .. HDMI 2.1a will have a new feature called 'Source-Based Tone Mapping (SBTM) ' as an option.

HDMI 2.1a Certification Announced Including New Source-Based Tone Mapping (SBTM) Feature --TFTCentral
https://tftcentral.co.uk/news/hdmi-2-1a-certification-announced-including-new-source-based-tone-mapping-sbtm-feature

CES 2022 will introduce HDMI 2.1a, another confusing new spec --The Verge
https://www.theverge.com/2021/12/29/22856103/hdmi-2-1a-spec-standard-mess-cables-source-based-tone-mapping-ces-2022

SBTM is a function that conveys a part of HDR mapping information from the video source device side along with the tone mapping performed by the TV or monitor. It's not a new HDR standard that replaces HDR10 or Dolby Vision, it's just an option to better optimize the content you send to your display.

SBTM is a function designed for PCs and game consoles. For example, one window on the display can display a beautiful image, while another window can optimize the image with black text on a white background, requiring slider adjustments and manual settings by the user. plug. SBTM is optimized and transmitted by the video source device when outputting a combination of contents with different dynamic range standards. However, for SBTM to work, both the source device, which is the input device, and the display, which is the output device, must be compatible.

The HDMI Forum said, 'SBTM is a new HDR feature that allows input devices to do some of the HDR mapping in addition to tone mapping by the display. SBTM allows source devices to take full advantage of the display's potential. You can adjust the output to send video signals that take full advantage of the HDR capabilities of a particular display. SBTM adds powerful new HDR capabilities to HDMI-enabled products to further enhance your viewing experience. I will improve it. '

SBTM, like variable refresh rate (VRR), automatic low latency mode , eARC, etc., is just an option for HDMI 2.1a and is not a requirement for HDMI 2.1a activation. Whether or not the device supports SBTM is up to the manufacturer of the video source device or display, and even if it does not support SBTM, it is possible to obtain license approval.

There are many criticisms about this HDMI license authentication attitude of 'thinking about new functions added by version upgrade as an option'. For example, HDMI 2.0 has a narrower communication bandwidth than HDMI 2.1 and has a limited amount of video that can be transmitted, but HDMI Licensing Administrator, the licensing organization of the HDMI Forum, has abolished the licensing of HDMI 2.0, so it will be changed to HDMI 2.0. The problem was that the monitor that only supports HDMI 2.1 is not compatible with various options, which is difficult for consumers to understand.

Is it false to advertise a monitor that only supports HDMI 2.0 as 'HDMI 2.1 compatible'? --GIGAZINE

Similar to this monitor, all HDMI compatible devices will be certified by the 2.1a method in the future, but the HDMI version number will be displayed to the manufacturer just by sticking the sticker that says 'HDMI'. There is no obligation to do so, and which options are supported is noted on the official HP and catalog spec sheets. At the time of writing the article, the reliability of HDMI 2.1a certification is left to the conscience of the manufacturer, and it is easy for consumers to get confused when they want to purchase 'HDMI 2.1a certified equipment'.

'I think this update to HDMI 2.1a will add to this confusion, because the new version means feature changes and improvements for many,' said TFT Central, a video equipment news site. But in reality, SBTM is just an option, not necessarily included, 'he said, criticizing HDMI's versioning and licensing system.