HDMI 2.1  

HDMI 2.1 Specification

Learn About The HDMI 2.1 Specification

HDMI 2.1 is currently the most advanced HDMI AV connectivity specification 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.

HDMI 2.1 products from C2G coming soon in 2021!

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.

Higher Video Resolutions and Refresh Rates

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.

Dynamic HDR

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.

Ultra High Speed HDMI Cables

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 "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. The important caveats here are that, not all HDM 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 (QMS) — eliminates the blank screen before content is displayed
    • Quick Frame Transport (QFT) — reduces latency and lag
HDMI Features 1.0 1.1 1.2 1.3 1.4 2.0 2.1
Full HD Blu-ray Disc and HD DVD video
Consumer Electronic Control (CEC)
Super Audio CD (DSD)
Auto lip-sync
Dolby TrueHD / DTS-HD Master Audio bitstream capable
Updated list of CEC commands
3D video
Ethernet channel (100Mbps)
Audio return channel (ARC)
4 audio streams
2 video streams (Dual View)
Static HDR
Dynamic HDR
Enhanced audio return channel (eARC)
Variable Refresh Rate (VRR)
Auto Low Latency Mode (ALLM)
Quick Media Switching (QMS)
Quick Frame Transport (QFT)