HDMI 2.1 Spec Officially Released: A Primer

HDMI 2.1 spec calls for 48GHz bandwidth supporting HDR, wider color gamut, 8K @ 60Hz, 4K @120Hz and 10K for commercial applications.


The much-anticipated HDMI 2.1 specification has been released by HDMI Forum, Inc. The new spec, which HDMI Forum announced was coming during CES 2017 with only a few details, is now available to all HDMI 2.0 adopter. The new version supports a range of A/V formats, including 8K video at 60Hz and 4K video at 120Hz. The 48Gbps bandwidth speed that was one of the few leaked bits of information earlier this year, remains in the final spec.  

“The HDMI Forum’s mission is to develop specifications meeting market needs, growing demands for higher performance, and to enable future product opportunities,” says Robert Blanchard of Sony Electronics, president of the HDMI Forum.

New HDMI 2.1 Specification: Backwards Compatibility

Backwards compatible with with earlier versions of the HDMI format, the new version HDMI 2.1 specification was developed by the HDMI Forum’s Technical Working Group.

The HDMI 2.1 Compliance Test Specification (CTS) will be published in stages throughout the first three quarters of 2018. HDMI Forum says that it will notify adopters when they release CTS materials.

Check out the HDMI 2.1 primer in the slideshow

Increased High-Definition Compatibility

HDMI 2.1 is compatible with 4K at 120Hz, 8K at 60Hz, and 10K resolutions for commercial A/V applications.

The format includes high dynamic range (HDR) support to help ensure improved video performance with improved depth, detail, brightness, contrast and wider color gamut capabilities on a scene-by-scene or frame-by-frame sequence.

Other highlights include:

  • Ultra High Speed HDMI Cable supports 48Gbps bandwidth for uncompressed HDMI 2.1 support, with low EMI emission and backwards compatibility with earlier HDMI specifications.
  • The format’s eARC is designed to simplify connectivity, while providing ease-of-use, and it helps to ensure compatibility between audio devices and upcoming HDMI 2.1 products.
  • Improved refresh rates for smoother images and more seamless transitions for gaming, movies and video content.
  • Quick Media Switching (QMS) for movies; this feature eliminates delays that result in blank screens before content is displayed.
  • Quick Frame Transport (QFT) reduces latency for an improved gaming experience.
  • Auto Low Latency Mode (ALLM) enables the correct latency setting to automatically set for smoother, lag-free uninterrupted viewing.

To learn more, visit the HDMI Forum at the upcoming 2018 Consumer Electronics Show (CES) in Las Vegas on Jan. 9-12 in LVCC South Hall 1 booth 20542.

About the Author

Robert Archer
Robert Archer:

Bob is an audio enthusiast who has written about consumer electronics for various publications within Massachusetts before joining the staff of CE Pro in 2000. Bob is THX Level I certified, and he's also taken classes from the Imaging Science Foundation (ISF) and Home Acoustics Alliance (HAA). Bob has also served as the technology editor for CE Pro's sister publication Commercial Integrator. In his personal time beyond his family, he's studied guitar and music theory at Sarrin Music Studios in Wakefield, Mass., and he also studies Kyokushin karate at 5 Dragons and Brazilian jiu-jitsu at Binda Brazilian Jiu Jitsu.


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