OK, let's get this done up front. Yes, there's a new cable with HDMI 2.1, but you don't need to upgrade. At least not yet.

HDMI 2.1 brings new features and a lot more bandwidth to the venerable cable and connection. However, it's going to be many years before you'll see it on the average television. If you've got your eye on a fancy new high-end TV though, there are some things you should keep in mind. We'll get to those further down.

The good news is, the connector itself isn't changing. Your current cables will work even when you finally get a device with HDMI 2.1. You will need new cables to take advantage of the new features and resolutions possible with 2.1 but again, it will be years before those become commonplace.

Read more: Best HDMI cables for your new 4K and HDR TV

Today's devices mostly use HDMI version 2.0, or one of its several iterations. We'll see a handful of TVs in 2019 with full or partial 2.1 implementations.

How does that affect you? Not much. You can't upgrade your current TV to 2.1 spec, and there are no HDMI 2.1 sources yet. This update is quite forward-thinking and takes into account formats and resolutions that won't be widely available for years. However, if you're considering certain new TVs in 2019 and beyond, you should make sure you understand the limitations of 2.0, and what 2.1 will offer if you choose to wait on your TV purchase.

Sarah Tew/CNET

The short version

Don't like reading (much)? Allow me to fire some HDMI 2.1 bullets.

The physical connectors and cables the same as today's HDMI.

Improved bandwidth from 18 Gbps (HDMI 2.0) to 48 Gbps (HDMI 2.1).

Can carry resolutions up to 10K, frame rates up to 120fps.

New cables are required for higher resolutions and/or frame rates.

The first products will arrive in 2019.

The increased resolution and frame rate possibilities are a futurist's dream:

4K50/60

4K100/120

5K50/60

5K100/120

8K50/60

8K100/120

10K50/60

10K100/120

You should be able to get 4K/60, and a basic 8K/30, with current cables, but the rest will need an Ultra High Speed HDMI cable. More on these new cables below.

On the color front, 2.1 supports BT.2020 and 16 bits per color. This is the same as HDMI 2.0a/b, and is what makes wide color gamut possible.

Those are just the highlights, though. Read on for the details.

Now playing: Watch this: Samsung Q900 85-inch 8K TV hands-on: A beautiful beast

All about the bandwidth

When you increase the resolution of a TV signal, the amount of data of that signal goes up. A 3,820x2,160 4K UltraHD signal sent over HDMI is roughly 4 times the amount of data as an HD 1,920x1,080 signal. If you think of cables as pipes, you need a bigger pipe to transmit a 4K signal than a 1080p one. The same is true if you increase the frame rate. You need a bigger pipe to transmit a 60 frame-per-second image than you do a 24fps image of the same resolution. More images per second, more data.

Though most current HDMI cables can handle nearly all of today's content, the TV industry never sits still. Down the road we might see higher frame rate TVs, and we're already starting to see higher resolutions, like 8K TVs. Don't worry, they're not going to be common any time soon either. Even way farther down the road, maybe we'll even see 10K TVs.

This is predominantly what HDMI 2.1 is for. Not for 99 percent of people now, but for the future versions of ourselves who want to send their 4K TVs native 120fps material, or their 8K TVs 60fps material. Far future versions of ourselves playing content that doesn't currently exist...

Unless you're a gamer. Personal computers, and high-end gaming rigs at that, are the only current source that can output 4K at more than 60fps. The Xbox One X can do 120fps, but only at lower resolutions and therefore doesn't require HDMI 2.1. Other than gaming, there's basically no current content that requires the bandwidth of HDMI 2.1. Since there's no indication of movies or TV moving towards higher framerates, except for perhaps sports, the higher framerates possible with the HDMI 2.1 specification are likely to go unused by most people. Yes, in theory you could finally send your 120 Hz TV a 120 Hz signal (which isn't how they work now), but again, there's no non-gaming 120 Hz content now or planned, so this is pretty unlikely.

Already we're seeing 8K TVs, and to get fully-featured 8K content to the TV, you will need HDMI 2.1. Since even 4K is higher resolution than most people need, given common TV sizes and seating distances, 8K is really overkill. However, TV manufacturers love increasing resolution because it's relatively easy to improve, and makes for an easy marketing push as "better." It's inevitable 8K TVs will be common, but that's many years away. Plus, those TVs will be better and cheaper than today's models.

It's worth keeping in mind that there are currently no public discussions about 8K sources, so even if you get an 8K TV, you'll have nothing to plug into it except your current 1080p and 4K sources. So if you want to get an 8K TV now, don't worry about finding new cables that will pass 8K resolutions (more on these below). Since there likely will be 8K sources eventually, you should definitely make sure your 8K TV has HDMI 2.1 so you can use them. If you don't, you run the risk of your expensive 8K TV not being compatible with whatever 8K source finally arrives. This is exactly what we saw with early 4K TVs, none of which are able to play content from 4K Blu-ray players or 4K media streamers.

Useful additions

While the new resolutions and frame rates get all the headline buzz, but there are some other improvements that will be more useful for most people.

"Dynamic HDR" is an amusing name for a big improvement. High dynamic range is our favorite picture-quality improvement since high-definition itself, and right now the most common HDR format is HDR10. It uses something called metadata to tell the TV how to treat a piece of HDR content. In the current version of HDR10, that metadata is applied once and once only, on a per-program basis. As in, you get One Set of Data to Rule Them All.

Dynamic HDR can vary how each scene or even each frame looks, not just the program as a whole, to better suit that scene (or frame). Here's a video that shows some examples (but remember, you're viewing it on non-HDR screens). Basically, a dark scene with bright highlights (campfire at night) would take advantage of HDR differently than a bright scene with dark areas (someone under a pier on a beach at noon). If these scenes were in one movie, static HDR would treat these the same, while Dynamic HDR would let each scene look its best. HDMI 2.1 enables Dynamic HDR, but it also needs to be present in the content to work.

Dolby Vision, HDR10+, and certain flavors of Technicolor's Advanced HDR, already uses dynamic metadata and can pass over a existing HDMI connections. This aspect of HDMI 2.1 ensures going forward this will be possible without a proprietary format (HDR10 has no licencing fees).

HDMI Forum

"eARC" is the next evolution of Audio Return Channel, which allows simpler connections between AV devices like TVs, video players and sound systems. eARC has support for "the most advanced audio formats such as object-based audio, and enables advanced audio signal control capabilities including device auto-detect."

Basically this means Dolby Atmos over ARC at full resolution, which you currently can't do. However, your current cables probably can. If, in the future, you buy an HDMI 2.1-compatible TV and an HDMI 2.1-compatible sound bar, your current High Speed cables should be able to transmit eARC. Audio doesn't require the bandwidth that video does.

HDMI Forum

"Game Mode VRR" is a potentially interesting feature for gamers. It allows for "variable refresh rate, which enables a 3D graphics processor to display the image at the moment it is rendered for more fluid and better detailed gameplay, and for reducing or eliminating lag, stutter and frame tearing." In other words, there will be less of a buffer for frames while the video card creates the image so you won't have to choose between image artifacts and input lag, ideally reducing both. If this sounds familiar, it's because it's similar to Nvidia's G-Sync and AMD's FreeSync, both only available over DisplayPort. We wrote more about this feature in How HDMI 2.1 makes big-screen 4K PC gaming even more awesome.

Game Mode VRR will also work over current cables (between two pieces of 2.1-compatible gear), though if you're trying to push greater-than-4K60 video, you'll need an Ultra High Speed HDMI cable.

Speaking of that...

New cable

For the first time in a while, there is a new cable. It looks... well, it looks the same as the old cable. There's no new connector; that stays the same. These were originally called "48G" cables since they will have 48 Gbps bandwidth, though now they're officially called Ultra High Speed HDMI cables. These have roughly 2.6 times the 18 Gbps that the better-made HDMI cables have now. These cables are backward compatible, so they'll work with all your other HDMI gear (at whatever speed that gear operates).

HDMI Forum

There's no reason to buy an Ultra High Speed HDMI cables cable now. The first generation of these cables are rare, overpriced, and do nothing for your current gear. When, down the road, you have gear that can take advantage of the extra bandwidth or features, then you should upgrade. They'll be cheaper then, too. Check out What HDMI cable do you need? for some cheap options now.

We found out some other interesting HDMI cable info at CES 2019, like how longer, copper cables might not work, and how there was no compliance testing yet. The latter means that cables labeled Ultra High Speed in 2018 and early 2019 might work, and they might not. HDMI Licencing has no way of testing them yet. Yet another reason to hold off buying new cables.

When?



We'll start to see TVs with HDMI 2.1 in 2019, with more in 2020 and beyond. However, not all TVs that claim HDMI 2.1-compatibility are actually capable of everything we've discussed. HDMI Licensing, the organization in charge of the HDMI specification, is allowing companies to claim 2.1 compatibility even if they don't support every aspect. So a TV that can't accept 8K/60, but has eARC and Variable Refresh Rate, still can claim it's 2.1... as long as the company specifies what aspects of 2.1 it can support. This is bound to lead to confusion, as it will no longer be possible just to check what version of the connection a product has, but also what features of 2.1 the product may or may not support. Ideally these aspects will be easy to spot, but given how many features and tech specs every TV already has, this unquestionably makes things just that little bit more difficult.

If you are buying an 8K TV, don't expect the manufacturer to add any HDMI 2.1 features the TV lacks when new. It's possible that a firmware update might give your TV those capabilities if it doesn't out of the box, but then, it might not. TV manufacturers are very hit-or-miss when it comes to adding features to older televisions. Sometimes it's not physically possible, other times it's not economically possible.

HDMI 2.1 is like a brand new 10-lane highway in the middle of the countryside. There's not much reason for it right now, but it offers an easy way to expand in the future. If you're not considering an 8K TV then it's a 10-lane highway in the countryside of a different state or country. Cool, but not something that will impact your immediate future.

Got a question for Geoff? First, check out all the other articles he's written on topics such as why all HDMI cables are the same, LED LCD vs. OLED, why 4K TVs aren't worth it 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 sci-fi novel and its sequel.