HDMI Organization Adds Source-Based Tone Mapping to HDMI 2.1a

The HDMI Licensing Administrator has released details about the Source-Based Tone Mapping feature of the HDMI 2.1a specification that the organization is working on. This function should improve the HDR display.

Source-Based Tone Mapping or SBTM allows source devices such as set-top boxes, PCs and game consoles to adapt the HDR display to the HDR characteristics of the screen. The HDMI LA gives the 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 enhancement of HDR rendering 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 through a firmware update and does not require new cables. However, screens must also be supported. For televisions, this can also be done via firmware updates, for example.

SBTM will be an optional part of HDMI 2.1a, the upcoming version of the HDMI specification. That means not every HDMI 2.1a certified device will support the feature. According to the HDMI LA, manufacturers can indicate with their marketing materials whether there is SBTM support.

Display simulated by the HDMI LA that should give an impression of SBTM from HDR 2.1a.