It wasn't too long ago that the HDMI Forum, the organization in charge of that ubiquitous audio/video connection, announced version 2.0. Then HDMI 2.0a, HDMI 2.0b, and most recently, HDMI 2.1.
So what do they mean to you?
On one level, HDMI versions shouldn't matter. In fact, many manufacturers don't list the HDMI version used on their televisions, video players and other devices. You're generally safe assuming that a new 4K HDR TV you buy will work with a new 4K HDR video player, and pass the highest-quality signals available to each. You're also safe using cheap.
When trying to connect equipment that isn't brand new, however, the HDMI version can matter a lot. That's because older HDMI devices might not be able to pass along the newest video formats, namely 4K and HDR, or the highest-quality versions of each. If you're worried about about that, it pays to know the HDMI version of the device you're buying.
Behind the version numbers
If you're shopping for any product with HDMI in 2017, you should make sure it has at least HDCP 2.2, the copy-protection protocol, so you can actually watch 4K content sent from an external device (like a Roku or 4K Blu-ray player).. This gets you 4K resolution and frame rates of at least 60. More importantly, it gets you
What's more, every piece in your AV chain needs HDMI 2.0/HDCP 2.2 for it to work. So if you have an HDMI 2.0 4K player and an HDMI 2.0 TV, but an older HDMI 1.4 soundbar or AV receiver in between… you're out of luck.
Most of "b" is a carryover from "a" and "_" versions of 2.0, with some refinements, most notably Hybrid Log Gamma (HLG). This is a different way to transmit HDR content. For a deep dive, one of the co-creators is the BBC and it's got a well-written PDF Q&A.
For now, though, don't worry about it. There's not much support for HLG yet. The only reason 2.0b is worth mentioning is it's being implemented on 2017 TVs instead of HDMI 2.1. Which brings us to…
The big jump to 2.1
HDMI 2.1 is the upcoming update, and it is a significant jump. It takes everything from 2.0b and adds insane things like 10K resolution at a whopping 120Hz, far beyond anything any TV can do now or will be able to do in the near future. HDMI 2.1 is like buying an industrial excavator because you think you might plant roses someday. It's doubtful you'll see many products implementing the full 2.1 spec this year, but maybe next year.
This huge leap does require new cables, but only if you want to pass the higher resolutions and framerates. These new cables are part of this new spec. Called "48G" cables, they're a much larger "pipe" for this deluge of data to pass through.
For all the details, check out HDMI 2.1: What you need to know.
In sum, here's a table comparing the capabilities of the formats.
HDMI versions compared
|HDMI Version||Max Resolution||Max 4K Frame rate||HDCP 2.2||HDR||WCG||Hybrid Log Gamma||Dynamic Metadata|
No new cables… probably
But the good news is, you don't actually need new cables for HDMI 2.1 (or 2.0a or b) on two conditions:
- You're only using "normal" resolutions like 4K/60 or less (i.e. pretty much all content and TVs).
- Your current cables are fully up to the High Speed spec laid out many years ago.
The first point is easy. Unless you're a PC gamer and you know your TV/monitor can handle higher frame rates, you don't need to worry about going higher than 4K/60. All other content is 4K/24 or 4K/25 and less.are conversions inside the TV, and not transmitted over any cable.
The second part is harder to determine. If you bought an HDMI cable a few years ago, regardless of price, it's possible it will handle 4K resolutions. It also might not. The only way to tell is by trying it. If you're not getting a picture, or the picture cuts out, your cable might not be able to handle the resolution and/or frame rate you're sending. If that's the case, a new cable is likely required (though it doesn't have to be expensive).
For more info, check out When should I upgrade my HDMI cables?.
What version for me?
As mentioned before, anything you buy now should be at least HDMI 2.0, and honestly it will be surprising if you find a mainstream production that isn't 2.0 at this point. Most manufacturers won't specify "a" or "b", though if the product claims to do HDR, it's probably at least 2.0a, and quite possibly 2.0b.
The question becomes: Can a product can be upgraded, via a firmware update, to become "a", "b", or ".1"? The answer is: maybe, maybe and probably not. HDMI Forum, the people behind the HDMI standards, are understandably reluctant to discuss what manufacturers are able to do. We can figure a few things though.
Most HDR-compatible devices will have likely shipped from the factory with 2.0a. Since HDR is something that requires serious hardware, there's no point in adding the ability to read HDR data in a TV that isn't HDR. So the only products that could need 2.0a but didn't ship with it are slightly older (around 2 years) source devices. Is it theoretically possible to add it? Yes. Likely? Probably not. Companies don't love updating old gear with new features.
Changing 2.0a to 2.0b is much more likely, as it's a minor change. As mentioned though, it's not a change you need to worry about right now.
Changing from anything to 2.1 is highly unlikely. The issue is the chips inside the TV itself, which have to be able to handle a lot more data. Remember, even though your TV can only display 4K/60, to be "HDMI 2.1" the HDMI chips need to be able to handle 10K/120. It would be like Toyota putting racing tires on your Camry at the factory. Sure the grip is great… but why? This is one of the reasons why 2017s might have 2.0b, but none will likely have 2.1. The other reason is because the final 2.1 spec isn't finalized yet (as of this writing).
Will your next TV have HDMI 2.1? If you get one next year, maybe. 2019? Probably. For now though, it's not worth worrying about.
And of course, all the versions are backward-compatible, so you can connect your HDMI 1.4 Blu-ray player to your HDMI 2.0b TV and you shouldn't have any issues.
"Shouldn't" being the key word -- but then, that's HDMI.
Got a question for Geoff? First, check out all the other articles he's written on topics like why all HDMI cables are the same, TV resolutions explained, LED 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.