HDMI 2.0 and its newer sibling HDMI 2.0b are still the most common versions of the HDMI standard, but as of 2020, their market share will start to decline, as the industry makes way for the latest and greatest version: HDMI 2.1.
But because HDMI 2.1 is still so new, and the number of devices that support it is so few, you probably have tons of questions. Maybe you’re worried about whether your new 4K TV, streaming media player or 4K Ultra HD Blu-ray player is already out of date? Or maybe you’re concerned that you’ll need to purchase a bunch of new HDMI cables? Then there are the deeper questions surrounding HDMI 2.1: What does it do, and why do I need it?
We’ve got all the answers right here, and while the subject matter is a little technical, we’ve made every effort to break it down in a way that is meaningful to both the average Joe and the hardcore A/V enthusiast. Let’s start with the biggest burning questions.
Is my new TV about to become obsolete?
Absolutely not. If your TV supports 4K UHD resolution and High Dynamic Range (HDR) — or even just 4K — it is far from obsolescence.
If you bought your TV within the past couple of years, you’re good to go for a while.
It’s true that HDMI 2.1 opens up a wealth of new possibilities, which we’ll get into shortly, but the full benefits of these features won’t be realized for many years. The changes are exciting, but it will be years more until specs like 8K TV resolution and 4K at 120Hz are anywhere close to mainstream.
Bottom line: If you bought your TV within the past couple of years, you’re good to go for a good while.
If I’m thinking of buying a new TV, should I wait?
In the past, our advice was no, go ahead and buy a new 4K TV with confidence — HDMI 2.1 was still too far away. But CES 2020 has changed our tune. We saw tons of new TVs in Las Vegas, and while they didn’t offer revolutionary features they all had two things in common: Better picture quality and HDMI 2.1 support. Well, all except Sony, which seems to be sticking with HDMI 2.0b for now.
These new models aren’t just concepts or one-offs. They’re real and heading to retailers later this year and we expect them to set new levels of affordability. That’s why our new advice is to wait — especially if you want to be as future-proof as possible. Within a few months, you’ll be able to buy TVs with the latest version of HDMI, and they likely won’t cost any more than the older models did during most of 2019.
Does HDMI 2.1 require new HDMI cables to work properly?
Yes. As you’ll learn in the specs-oriented tech explanation of HDMI 2.1 below, the new standard nearly triples the amount of data that can fit down an HDMI cable at once. That being the case, to take full advantage of HDMI 2.1, the use of a new Ultra High-Speed Certified HDMI cable will be required.
In some rare instances, it may be possible to use an existing Certified High-Speed HDMI cable with a newer HDMI 2.1 device, but since the amount of information being crammed down this digital pipeline is increasing at a rapid rate, it would be wise to buy new Ultra High-Speed HDMI cables at the same time any devices supporting HDMI 2.1 are purchased. Don’t worry though, in most cases they’re not much more expensive than High-Speed HDMI cables.
Wondering which HDMI cables you should buy? Check out our list of recommended HDMI cables for all kinds of devices and installations.
Note: Nothing is changing about the size or connection type of the HDMI cable ports and jacks. The new Ultra High-Speed HDMI cables will fit perfectly into older devices.
Is HDMI 2.1 backward compatible?
Yes. You will be able to connect any HDMI-enabled device supporting any older version of the HDMI standard, and it will work just fine on a new HDMI 2.1-enabled TV or display. Ultra High-Speed HDMI cables are backward-compatible too. For instance, if in the future you want to connect your then-archaic Xbox One to your shiny new 8K TV with HDMI 2.1, that won’t be a problem at all.
Can my HDMI 2.0b devices be firmware upgraded to HDMI 2.1?
In theory, this is possible, but it is highly unlikely. Jeff Park, director of technology at HDMI LA, informed us that while there are premium chips out there which can be firmware upgraded, they are extremely expensive and rarely used by manufacturers. Chances are, your existing HDMI 2.0b devices don’t have one of those rare chipsets built into them.
Why do we need a new HDMI version?
Believe it or not, consumer-level home entertainment devices can already approach the 18Gbps bandwidth limits of HDMI 2.0b. Take a 4K Ultra HD Blu-ray disc, for instance (heck, take the best 4K Ultra HD Blu-ray discs!): 4K image resolution on its own is a big bandwidth hog, but then add 10-bit color, 4:4:4 color sampling, 60 fps content, Dolby Atmos and DTS:X multi-channel surround sound, HDR metadata, and all the other little bits that need to get from a 4K Ultra HD Blu-ray player or a streaming media player to a TV, and you get close to maxing out that 18Gbps limit.
How do you improve products if you’re already running out of space on the digital highway that carries all this video and audio information? You don’t. You have to pave a new highway, and that’s exactly what the HDMI organization has done with HDMI 2.1.
Beyond the high resolution and increased framerates Hollywood and game studios would like to use, more lines of communication needed to be opened up between devices sitting on either side of an HDMI cable. Right now, your Blu-ray player or game console can send tons of audio and video data to your TV, but it’s almost entirely a one-way conversation. By changing the way HDMI jacks and HDMI cables are structured, the HDMI organization was able to not only handle more traffic on the digital entertainment highway but also to route that traffic in a smarter way so that connected devices can maintain a proper, uninterrupted dialog about that traffic.
In other words, if HDMI 2.0b is our existing, choked-up freeway system, then HDMI 2.1 is a mega-highway filled with autonomous cars driving themselves, immune to bottlenecks, and instantly adapting to traffic fluctuations. So what does that mean for you and your entertainment system?
What can HDMI 2.1 do that HDMI 2.0b can’t? What’s new?
As you’ve gathered by now, HDMI 2.1 can handle lots more information, and it’s easy to understand how that could translate into higher video resolutions like 8K, or even 10K. But the high-resolution capability is the least exciting part about HDMI 2.1 in our opinion, so while we’ll start with resolution specs, stick with us for the rest because HDMI 2.1 enables a more beautiful picture and an easier-to-use system than ever before.
HDMI 2.1 allows for higher resolutions at higher frame rates than before. With HDMI 2.0b we could enjoy a maximum of 4K resolution at a maximum frame rate of 60Hz. With HDMI 2.1, we can get 4K at 120Hz, 8K at 60Hz, and right up to 10K resolution for industrial and commercial applications. The resolution increase isn’t such a big deal on its own for TVs and projectors — we’re already close to maxing out the limit of detail our eyes can see at typical viewing distances — but adding higher framerates is great news for gamers. Higher framerates mean smoother, better-looking games. The HDMI organization says some Hollywood directors are eager to migrate to 120Hz native filming and want for that high-framerate content to make it into viewers’ homes as well as theaters.
The Audio Return Channel (ARC) is an HDMI 2.0b feature that lets audio move back and forth over an HDMI cable between a TV and an A/V receiver or soundbar. Unfortunately, the limited bandwidth of HDMI 2.0b means that audio is often compressed and reduced down to stereo. With Enhanced Audio Return Channel (eARC), we can now get uncompressed, full-resolution audio over HDMI 2.1 connections. Dolby Atmos is a perfect example. With ARC, Atmos only works when using Dolby Digital Plus, a compressed audio signal. eARC lets Dolby Atmos give its best performance using Dolby TrueHD, a lossless, high-resolution audio signal.
This will simplify system setups dramatically because it means users can connect everything to their TV and then run a single HDMI cable to their receiver or soundbar without losing sound quality. Fewer cables, less mess, better sound!
High Dynamic Range is already the best improvement to TV picture quality since 1080p HD, but it can be better. If you’re at all familiar with Dolby’s version of HDR, Dolby Vision, then you likely know the reason some reviewers consider it superior to other formats is that it is a dynamic HDR medium. In other words, Dolby Vision makes changes to the settings of an image as the image itself changes. The result is a more accurate, vibrant, and … well, dynamic picture.
The only hangup with Dolby Vision is that it is a proprietary technology and not every electronics manufacturer wants to pay licensing fees to use it. HDMI 2.1 brings dynamic HDR performance to other flavors, including the dynamic version of HDR10, known as HDR10+ and others, which should bring better HDR experiences to more TVs and more formats.
But wait, isn’t HDR10+ already possible using HDMI 2.0b? Technically, yes, but it’s not an officially supported technology when done over HDMI 2.0b. HDMI 2.1 makes it official, which in turn should make it highly reliable.
Variable Refresh Rate
As we mentioned in the section on resolution, HDMI 2.1 can support higher framerates for smoother video. But just as importantly from a gaming perspective, it allows for variable framerates. Modern PC and console games do not use a single framerate throughout the game. It varies, sometimes by quite a lot depending on the complexity of the scene. When framerates drop or speed up, there is a mismatch between what the game is providing and what the TV is set to display. To compensate, the TV has to do some guesswork and the result isn’t pretty. Lag, judder and frame tearing are all symptoms of trying to play VRR games on an HDMI 2.0b non-VRR-capable display. HDMI 2.1 gives TVs the ability to be perfect big-screen gaming companions.
Quick Frame Transport
This feature reduces the time it takes for a frame of video to pass from the source device (like a PC or console) to a display (like a TV or VR headset). Gamers will notice much less lag, especially those who like fast-action first-person shooters. VR will benefit from an equally reduced time between movements and the world presented through the goggles.
Quick Media Switching
You know that blank, black screen you get sometimes when you switch sources or from games to streaming apps? That’s going away forever.
Auto Low Latency Mode (ALLM)
Yet another improvement for gamers, ALLM lets a TV or other display know when the signal is coming from a game console or PC. When that happens, the display can automatically turn off any picture processing that could introduce latency or lag. You’ll never have to select Game Mode on your TV again.
No more lip-sync issues
Currently, it can be a hassle to sync up the video from your TV with the audio from your receiver or soundbar. This is because the TV may be using a heavy amount of processing, while the audio system’s processing takes far less time than the video processing. The result is a delayed output of a video signal relative to an audio signal, or the reverse effect — either way, your sound doesn’t match the timing of your picture. HDMI 2.1 will make it possible for TVs to talk in real-time to A/V receivers, soundbars, Blu-ray players, game consoles, and other source devices to ensure your video and audio are in perfect sync, all of the time.
That’s our rundown of HDMI 2.1. As you can see, the new standard opens up a wealth of new possibilities. Now, it’s time for manufacturers to decide how they take advantage of the new spec and turn possibilities into real-life benefits. As has always been the case in the tech world, sometimes watching the change happen is just as fun as experiencing the change itself.
Visit this page at HDMI.org to learn more about HDMI 2.1 specs.
Special thanks to Jeff Park at HDMI LA and Chris Heinonen of Wirecutter and Reference Home Theater for providing deep technical background for this article.