What Is HDMI 2.1? Here’s Everything You Need to Know

In the world of high-definition video and entertainment on the best TVs and more, HDMI reigns supreme. The technology has been around for years, but as we look ahead to innovations in resolution, picture quality and audio quality, a new technology called HDMI 2.1 is ready to take off.

Credit: Shutterstock

(Image credit: Shutterstock)

At first blush, HDMI 2.1 doesn't look all that different; in fact, some HDMI 2.0 TV and displays can masquerade as HDMI 2.1 devices. But when you consider its huge boost in bandwidth, support for up to 10K content and benefits for gamers — not to mention a new enhanced audio return channel — the standard should deliver a much more appealing experience.

HDMI 2.1 is still a largely unknown quantity. And while it promises to dramatically improve your home-entertainment experience in the future, there are still some things you should know about it now. Here's the scoop on HDMI 2.1.

Wait, there are different HDMI versions?

You might think that HDMI is a simple standard, but it's more nuanced than that. In fact, there are several HDMI versions that all offer different bandwidth, quality opportunities and other factors to consider.

For instance, HDMI 2.0, the prominent HDMI version today, comes with 18Gbps bandwidth, compared with 48 Gbps for HDMI 2.1. It's a similar story for supported resolutions and frame rates and other factors.

When it comes to HDMI, the higher the number, the better.

HDMI 2.1: Give me the basics

HDMI 2.1 is a new physical connector that provides a pathway between your content source and your video source, like a TV. HDMI 2.1 is backward-compatible with older technology, so if you have an older set that doesn't support the new version, HDMI 2.1 will still work with it.

However, what HDMI 2.1 provides is more bandwidth, nearly tripling what the current 2.0 standard can provide. Additionally, the technology paves the way for resolutions of up to 10K and frame rates of up to 120fps. To put that in perspective, you can expect up to 60 frames per second in existing HDMI 2.0 setups and a resolution up to 8K. However, with HDMI 2.0, 8K is limited at 30 frames per second.

With HDMI 2.1, you can get 8K frame rates — and 10K frame rates, for that matter — of 120 frames per second. That's a huge leap forward as the first 8K TVs come to market this year.

We'll outline more specifics on the value of HDMI 2.1 below, but if you're looking for a tl;dr view of HDMI 2.1, think of it as a next-generation technology that will help usher in better-looking and smoother-looking visuals in your home entertainment setup.

Can I use the same cables and connectors?

To take full advantage of the increased bandwidth of HDMI 2.1 and everything that comes with it, you'll have to use a new 2.1-compliant cable. However, the technology comes with the same connectors and has the same one-cable design as predecessor technologies. So you won't need to fuss with new shapes and sizes for your upcoming connectors.

Credit: HDMI.org

(Image credit: HDMI.org)

What kind of bandwidth difference can I expect? And why does that matter?

In the world of video, the more bandwidth you have available to you, the more content you can pass through the cable to your television. And as you might expect, content that comes with really high resolutions or frame rates takes up a lot of space. And the more bandwidth you have, the better your chances of pushing that content through the wire.

HDMI 2.1 supports up to 48 Gbps bandwidth. That's double what you can get now from HDMI 2.0. So, while you might be able to pump 8K content at 30 frames per second through an HDMI 2.0 cable, you'll be pushing the technology to its limits. On HDMI 2.1, it'll be able to handle that with ease. In fact, you'll be able to drive 10K content at 120 frames per second through ah HDMI 2.1 cable and not worry about it.

I care a lot about resolution. How will that be affected?

HDMI 2.1 is all about boosting the resolution possibilities of content. And while we're having trouble getting 4K content and 8K content is on the horizon, 10K content can be pushed through an HDMI 2.1 cable.

Credit: HDMI.org

(Image credit: HDMI.org)

But before we get too far ahead of ourselves, it's important to note that 10K content isn't available yet. And while we saw 8K televisions at CES this year, 8K content available is really, really hard to come by. So, while HDMI 2.1 provides the opportunity to enjoy super-high-res content, you won't be able to experience it in any meaningful way soon.

Are there other benefits to HDMI 2.1 compared with HDMI 2.0?

Arguably one of the more important HDMI 2.1 improvements has nothing to do with video at all. In fact, audio devices, including soundbars and amplifiers, might benefit from HDMI 2.1.

In previous HDMI generations, the technology allowed for something called ARC, or Audio Return Channel. The technology allowed for audio to be sent between your television and audio equipment.

HDMI 2.1, however, will ship with eARC, or enhanced Audio Return Channel. With help from eARC, audio bandwidth will be significantly expanded and allow for more audio content to pass through the cable. That should ultimately translate to even better-sounding audio.

HDMI 2.1 will also come with support for Dynamic high dynamic range, or Dynamic HDR.

If you've heard of HDR, you know it's a technology built into content and televisions that allows for expanded contrast and color in video, creating far more attractive visuals.

Dynamic HDR, which will work with HDMI 2.1, will allow the content source to send far more HDR data through the wire. That means the scene's HDR data will be adjusted down to the scene level, allowing for far more precise pictures in everything you watch.

I'm a gamer. What kinds of benefits should I expect?

If you're a gamer, you're going to love HDMI 2.1.

In addition to all of the benefits outlined above, HDMI 2.1 also comes with enhancements that allow for fast-moving content to be more accurately depicted on the screen to create more lifelike gaming experiences.

Credit: Shutterstock

(Image credit: Shutterstock)

That’s achieved in part by a new technology called Auto Low-Latency Mode, which will automatically adjust the television's settings to ensure fast-moving content isn’t slowed down. Lag, in other words, could be tossed aside.

Additionally, HDMI 2.1 comes with both variable refresh rates (VRR) and quick frame transport (QFT) technology. If you've heard of AMD's FreeSync on gaming monitors, HDMI 2.1 brings that same technology to TVs and game consoles. With help from VRR, game consoles will be able to deliver video frames at the fastest speed possible, allowing it to stabilize and improve upon the visual experience. With help from QFT, latency will be reduced, ensuring your screen isn't taking too much time to interpret what the game console or graphics card is sending it.

Are 2019 TVs shipping with HDMI 2.1 support?

Good news. There are some televisions that will ship with HDMI 2.1 support this year, including the Sony Master Series Z9G 8K LCD TV, Samsung's 2019 8K models and LG's 8K and 4K models in 2019. And looking ahead, there's a good chance that HDMI 2.1 will become the standard technology for TVs, especially as 8K resolution gains prominence in the market.

Can I upgrade my current television to HDMI 2.1?

Sorry, but probably not. While a simple firmware update would be nice, the problem is HDMI 2.1 is a new technology that will likely require new hardware when it's all said and done.

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It's worth noting, however, that Samsung's 8K Q900S QLED TV, which came out last year, will get an option to upgrade to HDMI 2.1 sometime this year, according to Samsung. What that upgrade will entail has not been announced.

So, you’re saying my TV is now obsolete?

Not exactly.

There's no debating that HDMI 2.1 presents major new opportunities. And, yes, you will need to buy a new television eventually to take full advantage of all  its benefits. But for HDMI 2.1 to take off, we need actual content that can take advantage of it and use the technologies and resolutions outlined above.

So, while it's nice to be ahead of the curve, if you adopt HDMI 2.1 soon, expect to be about a year or two ahead of that curve before you can take full advantage of its value.

Don Reisinger is CEO and founder of D2 Tech Agency. A communications strategist, consultant, and copywriter, Don has also written for many leading technology and business publications including CNET, Fortune Magazine, The New York Times, Forbes, Computerworld, Digital Trends, TechCrunch and Slashgear. He has also written for Tom's Guide for many years, contributing hundreds of articles on everything from phones to games to streaming and smart home.