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2.1 HDMI Standards: Everything You Need to Know


With the launch of HDMI 2.1, certain AV devices such as TVs, computers and gaming systems can now have even more seamless connectivity and immersive experiences. In this article, we’ll discuss the differences between HDMI 2.0 and 2.1, the exceptional features HDMI 2.1 offers and a new type of cable you should know about.

HDMI 2.0 vs. 2.1: What’s the difference?

The key differences between HDMI 2.0 and 2.1 are substantial upgrades in bandwidth, video resolutions and refresh rates. HDMI 2.1 now supports a maximum bandwidth of 48 Gbps, 4K resolution at 120Hz and 8K resolution at 60Hz. On the other hand, HDMI 2.0 only supports a maximum bandwidth of 18 Gbps, 4K resolution at 60Hz and 1080p resolution at 120Hz. HDMI 2.1 also offers support for devices with 10K resolution, which are most used for commercial AV and industrial applications.

HDMI 2.1 features

HDMI 2.1 introduces new and advanced capabilities that amplify the overall viewing experience. These include the following:

  1. Dynamic HDR – HDR enriches video images with deeper black and brighter white colors, which offers more natural and realistic pictures. Dynamic HDR delivers better picture quality, compared to SDR and static HDR, by applying metadata to each scene. Metadata is additional information found within content used to optimize tone-mapping.
  2. Enhanced Audio Return Channel (eARC) – eARC is simply an improved version of Audio Return Channel (ARC) that offers higher bandwidth and speed. With ARC, an HDMI cable can transfer visual and audio information between AV devices such as TVs and amplifiers. And with the arrival of eARC, people can now enjoy better audio quality and use advanced audio formats, such as Dolby Atmos, Dolby TrueHD and DTS-HD Master Audio. It’s important to note, if you are using HDMI extenders to deliver the signal over long distances (which can be up to 328 feet), only select extenders will be able to pass a signal with eARC.
  3. Variable Refresh Rate (VRR) – VRR is an exclusive feature of HDMI 2.1 that automatically matches the display’s refresh rate to the frame rate of the content – meaning less lag and screen tearing. This capability is especially helpful for gaming consoles that undergo rapid drops in frame rates due to sudden image and color changes.
  4. Quick Frame Transport (QFT) – QFT is also another exclusive feature of HDMI 2.1 that reduces the latency between the source device and the display. QFT ensures that every single reaction is relayed onto the display in real-time, which results in faster response times and less lag.

HDMI 2.1a: Source-Based Tone Mapping (SBTM)

SBTM enables the source to transmit a video signal optimized for a display’s HDR capabilities to further elevate the viewing experience. SBTM can be used by PCs and other devices to eliminate the manual user optimization for HDR. In short, SBTM is used to supplement HDR10, HDR10+ and Dolby Vision formats.

HDMI 2.1b features

HDMI 2.1b introduces added features that offer elevated gaming capabilities and smoother transitions for movies and videos. These include the following:

  1. Auto Low Latency Mode (ALLM) - ALLM enables the ideal latency setting to automatically be set to allow smooth, lag-free and uninterrupted viewing and interactivity. In many cases, this is referred to as ‘game mode’ and it usually must be set manually. ALLM lets a game console, PC or other device send a signal to the display which will also activate sharper images to enhance the gaming experience.
  2. Quick Media Switching (QMS) - QMS eliminates A/V blackouts when an HDMI source device switches its video mode. This blackout occurs when the display needs to time realign to different resolutions and frame rates. However, with QMS, viewers can switch between different frame rates without any interruptions. It’s important to note that both the source and display will need to be QMS compatible.

Introducing a new type of cable

It’s important to note that 8K TVs and other devices designed with more advanced technology should be paired with a certified HDMI cable that meets the specs of the device. A cable that’s incompatible with the device may not work or even degrade the video quality.

When HDMI 2.1 was released, Ultra High Speed HDMI Cables were also introduced to the industry. Although these cables are visually identical to its earlier versions, Ultra High Speed HDMI Cables have about 2.6 times the 18Gbps bandwidth, while being backward compatible.

When buying Ultra High Speed HDMI Cables, be sure that they are certified and not counterfeit. Here’s how you can identify a certified Ultra High Speed HDMI Cable:

  • Find the Ultra High Speed HDMI Cable Certification label on all packages 
  • Be sure that the Ultra High Speed HDMI Cable logo is printed on the label 
  • Be sure that the Ultra High Speed Cable name is printed on the cable jacket 
  • Ensure that the QR code and holographic image can only be scanned by the HDMI Cable Certification app 

HDMI 2.1 offers higher bandwidth capabilities that support resolutions up to 10K, Dynamic HDR and faster refresh rates. As more customers begin to adopt 8K TVs and the latest gaming systems, it’s important to know the latest HDMI standards so you’re prepared to install a seamless AV setup for your customers. If you need Systems Design support, contact our team of industry experts, and they’ll provide you with integration tips, product recommendations and product comparisons for your projects. 

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