The High-Definition Multimedia Interface Forum (HDMI Forum) has announced the completion of the HDMI 2.1 specification, bringing the standard's first support for resolutions up to 10K and the slightly redundantly-named dynamic high-dynamic range (HDR).
Designed to be backwards compatible with existing HDMI standards, HDMI 2.1's primary reason for existing is to boost the display resolutions supported by the ubiquitous cable. A boost from 18Gb/s peak bandwidth in HDMI 2.1 - itself a major increase from HDMI 1.4's 10.2Gb/s - to 48Gb/s allows for high-resolution, high-refresh rate displays including Ultra HD (4K) at 120Hz and 8K at 60Hz, while resolutions of up to 10K are supported at lower refresh rates for 'commercial AV [audiovisual], industrial, and speciality usages.'
The new standard also includes updated support for high-dynamic range (HDR) content using so-called 'dynamic HDR,' which can adjust the display's settings on a scene-by-scene or even frame-by-frame basis. Additional improvements include Variable Refresh Rate (VRR) support for a reduction in screen tearing and stutter, Quick Media Switching (QMS) to eliminate the delay when switching between devices and resolutions, Quick Frame Transport (QFT) for lower latency when gaming or using HDMI for virtual reality (VR) tasks, Auto Low Latency Mode (ALLM) for automatic latency detection and configuration, and Enhanced Audio Return Channel (eARC) with a wider range of audio formats supported.
These improvements, however, come at a cost. The need for ultra-low electromagnetic interference (EMI) to support the higher bandwidth demands means that older HDMI 2.0 cables aren't compatible with the new standard, which requires cables specifically labelled as Ultra High Speed HDMI 2.1.
The HDMI Forum has announced it will be publishing compliance test specifications (CTS) for device certification in stages through to the third quarter of 2018, meaning it's unlikely that any HDMI 2.1 devices will be hitting the market before the end of 2018 at the very earliest.
September 18 2020 | 18:30