The HDMI Licensing Administrator has made public details about the source-Based Tone Mapping feature of the HDMI 2.1 A specification that the organization is working on. This feature should improve HDR playback.
Source-Based Tone Mapping or SBTM allows source devices such as set-top boxes, PCs, and game consoles to adjust the HDR display to the HDR properties of the screen. The HDMI LA gives as a scenario where this Advantage offers the display of different content types, such as SDR, HDR and dynamic HDR, at the same time. SBTM then allows the source device to optimize the combined display. Another scenario is that PCs and consoles automate an improvement in hdr playback so that users no longer have to do it manually.
SBTM is an addition to existing hdr techniques such as HDR10 and HLG and not a replacement, emphasizes the HDMI organization. The feature can be added to set-top boxes and other source devices by means of a firmware update and does not require new cables. Screens also need support. With televisions, for example, this can also be done via firmware updates.
SBTM will be an optional part of HDMI 2.1 A, the upcoming version of the HDMI Specification. That means that not every HDMI 2.1 a certified device will support the feature. According to the HDMI LA, manufacturers can indicate with their marketing materials whether there is SBTM support.