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Learn About The HDMI 2.1 Specification

HDMI 2.1 is currently the most advanced HDMI AV connectivity specification in widespread use and introduces a number of new features that impact commercial AV applications. This new spec introduces an increased range of higher video resolutions (up to 10K), refresh rates (up to 120Hz), dynamic HDR, and a total bandwidth of up to 48Gbps. Additionally, it defines a new cable type, Ultra High Speed HDMI Cable–an evolution of the Premium High Speed HDMI Cable.
Higher Video Resolutions & Refresh Rates

HDMI 2.1 specs support higher spatial resolutions and improved frame rates including 8K 60Hz and 4K 120Hz. These provide for improved display of full-speed motion that is common with sports, action movies, gaming, and virtual reality (VR). Additionally, other resolutions, including 5K and 10K, have been defined for commercial AV, industrial, and specialty uses.
Dynamic HDR

HDMI 2.1 specs leverage dynamic HDR which optimizes displayed video on a scene-by-scene or even a frame-by-frame basis. Dynamic HDR provides an extended contrast range providing darker blacks and brighter whites, along with greater image detail in all color spaces of the image.
Ultra High Speed HDMI Cables

HDMI 2.1 specs introduce this new HDMI cable type that is an evolution of the Premium High Speed HDMI Cables. These cables are designed, tested, and certified with the HDMI 2.1 specification and bandwidth requirements in mind. The good news is that this new HDMI cable type is backwards compatible, supporting all previous HDMI specifications.

Learn More About What HDMI 2.1 Delivers

Though it is explicitly stated that the certification program is mandatory for any cable that carries the Ultra High Speed HDMI Cable name, it is not clear that this cable type is a requirement to support all HDMI 2.1 features. It's important to examine the language that is used to describe these cables. It is stated that the Ultra High Speed HDMI Cable is "the only cable that complies with the stringent specifications designed to ensure support for all HDMI 2.1 features". As stated in our HDMI 2.0 specs page, bandwidth and length are inversely proportional to one another. This means that any short HDMI cable is likely to support HDMI 2.1 features. This important caveats here are that, not all HDMI 2.1 features may be supported simultaneously, and length is likely to be very limited for non-Ultra High Speed cable supporting HDMI 2.1 features.

In addition to the features listed above, HDMI 2.1 specs introduce other features including:
  • Enhanced Audio Return Channel (eARC) 
    • An evolution of previous Audio Return Channel (ARC), that now provides support for the latest audio formats up to 192kHz, 24-bit, and uncompressed 5.1 and 7.1, and 32-channel uncompressed audio.
  • Enhanced gaming and media features
    • For smoother and more seamless motion improving gaming, movies and video including:​​​​​​
      • Variable Refresh Rate (VRR) — reduces lag and stutter
      • Auto Low Latency Mode (ALLM) — automatically selects the ideal latency setting
      • Quick Media Switching — eliminates the blank screen before content is displayed
      • Quick Frame Transport (QFT) — reduces latency and lag