A New HDMI SBTM Feature Optimizes HDR by Pairing Devices and Displays

The HDMI Organization has proposed an update to HDMI 2.1 that would enable Source-Based Tone Mapping (SBTM). SBTM, which is included in the new HDMI 2.1a standard, is not a new HDR format; rather, it simplifies the process of matching existing HDR video to the display being used.

Notably, the HDMI Organization states that many devices can have their firmware upgraded to support SBTM; nonetheless, for the standard to work, both devices must be aware of and compliant with the standard.

HDR technology is gaining acceptance, which is welcome given the sometimes dramatically enhanced, vibrant, and immersive visuals it can produce. If there is a clear issue with HDR video in its current state, it is frequently due to the growth of HDR standards (e.g., HDR10, HDR10+, HLG, or Dolby Vision), as well as older SDR content.

SBTM overcomes several of the aforementioned difficulties by letting a source device to adapt its HDR output to the capabilities of a connected display or television. By mapping the signal provided to the available brightness, contrast, and gamut, modern displays can adapt to single HDR sources that employ disparate HDR standards. However, the HDMI Organization states that SBTM will be used when a source device "needs to integrate many types of material (HDR, SDR, dynamic HDR, and graphics) concurrently."