CNET logo Why You Can Trust CNET

Our expert, award-winning staff selects the products we cover and rigorously researches and tests our top picks. If you buy through our links, we may get a commission. Reviews ethics statement

HDMI 2.1 is here, but don't worry about it now

The final specification for HDMI 2.1 has been announced. Time for new gear? Not so fast.

Geoffrey Morrison Contributor
Geoffrey Morrison is a writer/photographer about tech and travel for CNET, The New York Times, and other web and print publications. He's also the Editor-at-Large for The Wirecutter. He has written for Sound&Vision magazine, Home Theater magazine, and was the Editor-in-Chief of Home Entertainment magazine. He is NIST and ISF trained, and has a degree in Television/Radio from Ithaca College. His bestselling novel, Undersea, and its sequel, Undersea Atrophia, are available in paperback and digitally on Amazon. He spends most of the year as a digital nomad, living and working while traveling around the world. You can follow his travels at BaldNomad.com and on his YouTube channel.
Geoffrey Morrison
6 min read
Mathias Appel/HDMI Licensing

The HDMI Forum has announced the final specification for HDMI 2.1. 

We've written before about HDMI 2.1 and how it's a significant leap in what is possible over the venerable A/V connection. Higher resolutions, frame rates and numerous additional features mean this is definitely a next-generation connection, and cable, despite looking exactly like every previous generation of HDMI.

But here's the thing: HDMI 2.1 is almost ridiculously future-proofed. Most of the stuff it adds, like higher resolutions and frame rates, won't be widely available for years, if they come at all. A TV bought today or next year that doesn't have HDMI 2.1 will still be able to play back the vast majority of available content in the highest quality. And we don't expect TVs with HDMI 2.1 to even go on sale until late 2018 or, more likely, 2019.

That's a long time to wait if you want a new TV now. So our advice is to not to worry about HDMI 2.1 when you shop for a TV in 2017 or 2018. Unless you're a hard-core PC gamer with a top-flight rig, you won't be missing anything.

That's said, here's what you need to know.

Best TV gifts for the 2017 holidays

See all photos

Up to 10K resolution

One headline feature in 2.1 is a huge jump in resolution: 10K! Take that, measly 4K! Since there are no TVs on the market, or on the horizon, that even remotely come close to this, it's merely "futureproofing" on the part of HDMI Licensing, LLC. It's irrelevant to you at this point. It's basically like putting P-Zeros on your Camry in the hopes that someday you might attach rocket boosters.

Like many of the new features, this capability is really there for VR and computer monitors, which will get higher-resolution displays long before TVs.

Higher frame rate

The other big jump is in higher potential frame rates, which specifies how quickly the image is refreshed on the screen. Again, this sounds way more interesting than the reality. Even though your TV might be 120Hz, that doesn't mean it has the ability to actually accept 120Hz video. That greater-than-60 refresh is done internally, and most TVs won't know what to do with a native 120Hz signal (one exception is certain Vizio TVs like the M series).

Just like 10K resolution, there are currently no sources (outside of a PC) that create high frame rates. Movies are still, almost exclusively, 24 fps. TV shows are 24, 30 or sometimes 60. This isn't likely to change in the near, or far, future. The few dabbles in higher frame rates in Hollywood were loved by some, hated by some. Not a compelling reason to change.

The increase in frame rate will likely be cool for PC gamers, but for everyone else, it's not a big deal. Gamers probably will like Variable Frame Rate even more, which we'll discuss below.

HDMI Licencing

These higher frame rates and resolutions are largely thanks to Display Stream Compression, a "visually lossless" compression that helps fit additional data over the same cables, without adding significant additional processing or reducing image quality. It's sort of like a ZIP or RAR file on your computer. Whatever images or documents you put inside the ZIP file take up less storage space, but when you remove them, they're the same file.

New cables required

There are new cables coming, now called Ultra High Speed. The "High Speed" moniker was a poor choice and, well, I guess we're stuck with it forever now.


A visual representation of how much more bandwidth the upcoming Ultra High Speed cables can handle. 18Gbps is plenty for nearly all current content.

HDMI Forum

These new cables, earlier called "48G," are able to handle the much-greater bandwidth required by the higher frame rates and resolutions of HDMI 2.1. That said… you don't actually need them. At least not right now. When you can get perfectly good cables for $5, there's no point in spending more on cables that likely won't be necessary in your system for years. And by then, the Ultra High Speed cables will probably be $5.

When you have gear that needs these cables, then consider them. For now, don't worry about it.

Gaming stuff

HDMI Forum

Perhaps the coolest feature for gamers is Variable Frame Rate. This lets the source, a PC say, and the TV sync up and vary the frame rate depending on the needs of the source. If you're not a gamer, you don't need to worry about this. If you are a gamer, it means a slight step up in image quality (or specifically, fewer artifacts), as the TV can wait for the video card to create the next frame, not requiring the video card to send what it's got at a set interval, as now. 

Check out how HDMI 2.1 makes big-screen 4K PC gaming even more awesome for more info.

HDR, QMS, QFT, ALLM, and more abbreviations

Though most of the versions of HDMI 2.0 had HDR, HDMI 2.1 brings dynamic metadata to the actual spec, much like what Dolby Vision has and HDR10+ wants to be. How this is implemented remains to be seen.

The other letter jumbles aren't huge deals, but are interesting in their own right. QMS is Quick Media Switching, which means you'll be able to switch between different resolutions or frame rates without your TV dropping to black for many, many seconds.

Quick Frame Transport reduces latency between the source and the TV, potentially reducing the input lag that required TVs to have a Game Mode. This is also helpful to make VR smoother.

Auto Low Latency Mode automatically engages which of the above modes the content needs, such as when switching from watching a movie to playing a game.


ARC, or Audio Return Channel, is one of the best A/V features in recent years and it's criminally underused. It lets the HDMI cable work as a two-way street, sending the audio from the apps on your TV back down to your sound bar or receiver. Handy.

eARC goes to the next level, allowing uncompressed 5.1 and 7.1 audio and Dolby Atmos/DTSx, and requires the ability to fix lip sync issues. It's a nice little step up.

The additional audio bandwidth uses the Ethernet channel on HDMI cables with Ethernet. Chances are if you've bought an HDMI cable in the last few years, it had Ethernet built in. Since this channel isn't likely to ever be used for its original intent, this is a great use of it.

dave3/HDMI Licencing


As you hopefully assumed, HDMI 2.1 will be backward-compatible with all your current HDMI gear. That doesn't mean the new features will be, mind you, but if you have a PS3 or old Blu-ray player, it should be able to connect to an HDMI 2.1 input on your future TV with no problem.

Bottom line: Don't fear HDMI 2.1

With the specification being finalized so late this year it's doubtful many (if any) 2018 TVs, due to be announced at CES in January, will offer HDMI 2.1. Maybe a few will trickle in toward the end of the year, but for the most part it won't be a thing on TVs until 2019.

Really, in 2018, only gamers should take notice. The Variable Frame Rate is very cool, but again, the TV needs to be able to take advantage of that feature. If it has that feature, it's HDMI 2.1. The opposite isn't true.

Don't rush out and get new Ultra High Speed cables either. These cheap cables will do just fine. Eventually, when you have gear that supports cables that need the extra bandwidth, then it might be worth getting. By then they'll be cheaper too. 

Got a question for Geoff? First, check out all the other articles he's written on topics like why all HDMI cables are the sameTV resolutions explainedLED LCD vs. OLED and more. Still have a question? Tweet at him @TechWriterGeoff then check out his travel photography on Instagram. He also thinks you should check out his best-selling sci-fi novel and its sequel.