HDMI 2.1 (2.1b)

What is HDMI 2.1?

HDMI 2.1 is an industry standard for transmitting and receiving ultra high definition video and audio signals over a single cable. Gamers and home theater enthusiasts use HDMI 2.1 certified devices because they can provide faster resolutions and refresh rates as well as enhanced audio capabilities.

Key Takeaways

HDMI 2.1 is an industry standard for transmitting ultra high definition video and audio signals.
HDMI 2.1 provides gamers and home theater enthusiasts with state-of-the-art playing, viewing, and listening experiences.
For full functionality, connected devices must both support HDMI 2.1.
HDMI 2.1 devices require Ultra High Speed HDMI cables to take advantage of all the standard’s capabilities.
Some devices that support HDMI 2.1 do not support every feature the standard offers.

How HDMI 2.1 Works

HDMI 2.1 works by providing a higher bandwidth pipeline for transmitting and receiving video and audio signals. This enables support for higher image resolution, faster refresh rates, and advanced features that reduce latency and enhance the viewing and gaming experience.

What Does HDMI 2.1 Do?

HDMI 2.1 provides a standard way for manufacturers to engineer the way their products transmit and receive ultra high definition digital video and audio signals. The HDMI Licensing Administrator (HDMI LA) is responsible for licensing and certifying HDMI products.

HDMI 2.1 Features

Here are some of the key features that HDMI 2.1 supports:

Higher resolutions and refresh rates

Supports resolutions up to 10K at 120Hz.

Dynamic HDR

Allows frame-by-frame adjustments to provide better contrast, brightness, and color accuracy.

Variable refresh rate (VRR)

Allows the refresh rate of the display to adapt to the frame rate of the source.

Auto low latency mode (ALLM)

Automatically switches the display to low latency mode for optimal gaming performance.

Quick frame transport (QFT)

Reduces latency to provide a more responsive gaming experience.

Quick media switching (QMS)

Reduces the time it takes for a display to switch between different video sources.

Do You Need New HDMI Cables?

To take advantage of HDMI 2.1’s features, users need to connect devices with an Ultra High Speed HDMI cable. This type of HDMI cable supports the increased bandwidth required for higher resolutions, faster refresh rates, and enhanced audio.

In professional settings, Ultra High Speed HDMI cables are often connected to an HDMI 2.1 wall plate that has HDMI 2.1 ports. Devices can also be connected directly from the HDMI 2.1 port to HDMI 2.1 port.

HDMI 2.1 vs. HDMI 2.0 & eARC

The table below highlights the key differences and similarities between HDMI 2.0, HDMI 2.1, and HDMI 2.1’s enhanced audio return channel feature, eARC.

Feature	HDMI 2.0	HDMI 2.1	eARC
Maximum Resolution	4K	10K	Depends on the underlying HDMI version
Maximum Refresh Rate	60Hz	120Hz for 4K, 60Hz for 8K	Depends on the underlying HDMI version
Bandwidth	18 Gbps	48 Gbps	Depends on the underlying HDMI version
Dynamic HDR	No	Yes	No
Variable Refresh Rate (VRR)	No	Yes	No
Audio Return Channel	ARC	eARC	Enhanced ARC, supports high-bitrate audio
Quick Media Switching (QMS)	No	Yes	No
Quick Frame Transport (QFT)	No	Yes	No
Auto Low Latency Mode (ALLM)	No	Yes	No

What Devices Use HDMI 2.1 Now?

Popular digital devices that are HDMI 2.1 certified include:

PlayStation 5 and Xbox Series X.
NVIDIA GeForce RTX 30 series and AMD Radeon RX 6000 series graphics cards.
ASUS gaming monitors.
Sony, LG, and Samsung 8K TVs.
High-end Panasonic, Sony, and LG OLED TVs.

HDMI 2.1 Applications

HDMI 2.1 is used by gamers, home theater enthusiasts, and professionals who want the best quality video and audio possible.

Gamers benefit from HDMI 2.1 features that reduce input lag.
Home theater enthusiasts appreciate the features that allow a more immersive viewing experience.
Video editing and graphic design professionals like the way HDMI 2.1 monitors render colors accurately.
Business professionals appreciate the way HDMI 2.1 presentation systems can display high-quality content on large screens in conference rooms and event spaces.

HDMI 2.1 Pros and Cons

Like all technical specifications, HTMI 2.1 has advantages and disadvantages. It’s important for the average user to weigh both before investing in HDMI 2.1-certified devices.

Pros

Increased bandwidth pipeline
Higher resolutions and faster refresh rates
Delivers frame-by-frame adjustments for contrast, brightness, and color
Reduces lag, stutter, and frame tearing by synchronizing the display’s refresh rate with the source’s frame rate
Supports high-bitrate audio formats like Dolby Atmos and DTS
Will automatically switch the display to low latency mode for optimal gaming performance

Cons

Advanced features require both the source and display devices to support HDMI 2.1 in the same way
Requires Ultra High Speed HDMI cables
Low adoption rate
HDMI 2.1 certified devices may only support some of the specification’s features
HDMI 2.0 may work just as well for the average user

The Bottom Line

Knowing HDMI 2.1’s meaning before purchasing a new TV, graphics card, or monitor can help you decide ahead of time whether you really need the advanced features that HDMI 2.1 certified devices can provide. (Hopefully, this HDMI 2.1 definition will help you avoid spending extra money on features you may not use!)

The bottom line is that HDMI 2.1 certified devices are not required to support all of HDMI 2.1’s features. Before you connect an HDMI monitor to an HDMI game console with an HDMI cable, for example, be sure to check the monitor and game console’s specifications to make sure they both support the feature(s) you are interested in.