HDMI 2.1: Everything You Should Know

The new HDMI 2.1 connection has become the standard for new televisions. And it goes way beyond offering a higher resolution and refresh rate. We will explain all its news.

Although we could already see it in some 2020 models, the new HDMI 2.1 standard is beginning to be included in a generalized way in the new 2021 televisions.

From its nomenclature, it seems like a simple update, but it goes much further. It includes many new features that will interest you if you want to watch 8K content, enjoy the best HDR in Netflix, HBO, or Amazon Video series and movies, or play video games on a PS5 or Xbox Series X console, among other things.

If you are going to buy a television in 2021, check if it includes an HDMI 2.1 connector because it provides a few extras and advantages compared to other types of connectors, as we are going to see.

It is something that few people take into account. Most buyers prioritize things like screen size, resolution, or the type of HDR you have. But the version of HDMI that the TV supports is also of great importance.

What does the HDMI 2.1 connection provide?

What is HDMI 2.1?

Although it’s starting to make its way to TVs now, the HDMI 2.1 standard was approved in 2017. This is normal since manufacturers usually take a while to incorporate technological innovations into their panels.

HDMI 2.1 was born to standardize two growing trends: the higher resolution and dynamic HDR of streaming platforms and the higher variable refresh rate that modern video games need to be enjoyed on a television.

Here’s a rundown of what’s new in HDMI 2.1, and we’ll explain each of them below.

What’s New in HDMI 2.1

  • Higher resolution and refresh rate: 4K, 8K, and 10K up to 120 Hz
  • Dynamic HDR
  • Transfer rate up to 48 Gbps
  • VRR (Variable Refresh Rate)
  • QFT (Quick Frame Transport)
  • ALLM (Automatic Low Latency Mode)

Resolutions up to 10K

The first improvement of HDMI 2.1 is in the higher resolutions and refresh rates that it supports. Perhaps at the moment, few people are interested in 8K and 10K resolution, but it is a bet for the future.

In addition, a 5K resolution is added for commercial videos and special uses.

Although previous standards already accepted 8K resolutions, the difference here is the higher framerate. HDMI 2.1 supports 60, 100, and 120 Hz in all resolutions. 

The 100 and 120 Hz rates are designed for multiplayer video games on powerful hardware such as PC gaming or the PS5 and Xbox Series X consoles. Playing with a high framerate reduces latency, that is, the delay between an action that you do with the command and the result you see on the screen, an important factor in competitive online games.

These are all the maximum resolutions that HDMI 2.1 supports:

  • 4K 50/60 Hz
  • 4K 100/120 Hz
  • 5K 50/60 Hz
  • 5K 100/120 Hz
  • 8K 50/60 Hz
  • 8K 100/120 Hz
  • 10K 50/60 Hz
  • 10K 100/120 Hz

Of course, it is also compatible with the old standards, that is, 1080p, 720p, etc.

To achieve such a resolution with so many images per second, you need high bandwidth, that is, transfer speed. HDMI 2.1 is capable of transferring up to 48 Gbps.

In addition, the HDMI 2.1 spec supports the most recent color spaces, which include BT.2020, with 10, 12, and 16 bits per color component.

Dynamic HDR

The dynamic HDR was added to the specification in timely updates (HDMI 2.0a and HDMI 2.0b) but now integrated into the final version.

HDR or High Dynamic Range is an image processing technology that offers more shades of black and white and a better transition from light to dark colors (and vice versa) in a scene. This offers higher image quality and more realism in dark and chiaroscuro scenes. dynamic HDR HDMI 2.1

A few years ago, the static HDR format, called HDR10, became popular. This standard applies certain values ​​to black and white, used throughout the entire movie or chapter of a series, regardless of variations between scenes.

It is a limited system because a movie can have many different types of lighting, which is why dynamic HDR was invented, such as Dolby Vision and HDR10 +. These standards allow independent black and white adjustments for each scene and even for each frame. This allows for a much more perfect image.

HDMI 2.1 supports all current formats HDR, both static and dynamic: HDR10, HDR10 +, dynamic HDR, Dolby Vision, HLG, etc.

EARC port

Most likely, your old TV has an HDMI ARC port, but few people know what it’s for.

It is a special type of HDMI that comes in handy if you connect a sound system, such as an amplifier or soundbar, to the TV. To connect these devices, you need an optical audio cable, in addition to the HDMI.

HDMI ARC simplifies connection by eliminating the optical audio cable. 

HDMI ARC does not improve the picture or sound, but it eliminates a cable, so you save yourself buying it or having an extra cable in the bookstore or lying on the floor.

The new HDMI 2.1 specification improves on this technology, which is now called eARC.

Adds support for the latest audio standards, such as DTS-HD Master Audio, DTS: X, Dolby TrueHD, and Dolby Atmos, with high bitrate rates, up to 32 channels of uncompressed audio, 192 kHz 24-bit sound, and uncompressed 5.1 and 7.1 channels.

In short, eARC supports more audio formats with higher sound quality than ARC.

VRR, ALLM, and QFT: Thinking about videogames

Video games have experienced an important boom in recent years. Television formats have been adapting to their demands since consoles are connected to televisions, and many users also use them with their gaming PC. In addition, there are now new ways to play through the cloud on a TV, with platforms such as Google Stadia and devices such as Chromecast.

HDMI 2.1 releases three technologies that will make gamers very happy. Let’s see them in detail.

1.VRR (Variable Refresh Rate)

For almost 100 years, televisions have had a fixed refresh rate. If the screen operates at 50 Hz, it can only display 50 images per second. This is suitable for video, such as a movie or television program, recorded with a camera at still images per second.

If, in other cases, developers prefer to maintain the highest graphic quality, at the cost of a lower framerate, with fewer images per second.

If the functions TV, for example, 60 Hz, corresponding to 60 fps or 60 fps, and the functions set at a variable rate between 30 and 40 fps, one series of faults occur in the image, as the judder, which is a kind of tremor in the image, or tearing, where the screen breaks into lines that are drawn at different speeds:Variable refresh rate

Gaming monitors have solved this problem using panels that have a variable refresh rate, with technologies like G-Sync and FreeSync. These panels change the images per second that they show at the same rate as the game, keeping on-screen movements always smooth.

HDMI 2.1 integrates Variable Refresh Rate (VRR), which means that panel Hz can change in real-time, as the game demands.

If you are going to buy a television to connect the PS5 or Xbox Series X, it should be HDMI 2.1 to take advantage of this important feature. In addition, latency is also reduced. And it is useful for video calls, for example.

2. ALLM (Automatic Low Latency Mode)

All televisions on sale in recent years include a low latency mode, which is usually called Game Mode. This mode must be activated manually in the TV menu, and what it does is reduce the response times of the panel, at the cost of deactivating some functions of the TV.

If you use the console for other things besides gaming, such as watching movies or series, it is quite annoying to activate or deactivate Game Mode, depending on what you do.

HDMI 2.1 includes a new mode called ALLM or Automatic Low Latency Mode, which detects when you are playing, activating Game Mode, and automatically deactivates it when you finish.

It does not provide specific improvements, except for the convenience of not having to activate and deactivate it manually.

3. QFT

The latest technology associated with video games is QFT or Rapid Frame Transport. When you are playing a game, from when you transmit an order by pressing a button on the controller, for example, to shoot, until you see the shot on the screen, there is a delay. It’s a delay of just milliseconds or tenths of a second, but in multiplayer online games, every millisecond counts.

Many things influence this delay, from the processing time of the order by the CPU and GPU of the computer or console to when the data travels through the HDMI cable and the speed with which the TV shows the image.

QFT or Fast Frame Transport is a new technology released in HDMI 2.1. It reduces this delay by reducing the time the image data takes to travel the cable. It only affects part of the chain, but it may be enough to notice lower latency while playing the game.

QMS (Quick Media Change)

In today’s TV, there are times when you are watching videos at a different resolution or refresh rate, and you notice that the screen goes black for a couple of seconds to change the resolution or the Hz.

The same is true if you switch from Cinema Mode to Game Mode, for example.

QMS is a technology that takes advantage of VRR, the variable refresh rate, to eliminate black screen pauses when you change resolution or refresh rate in real time.

It works with rates between 24 and 60 Hz.

Ultra HD Speed ​​Cable

If a TV, monitor, or other device has an HDMI 2.1 connector, all that means is that you can use its features. But what that panel can do depends on the cable we use.

All HDMI connectors are compatible with all cables, but the specifications of that cable are what rule.

If, for example, you connect an HDMI 1.4 cable to an HDMI 2.1 connector, you will only be able to see video at 4K and 60 Hz, even if the TV is 8K. And you won’t be able to play at 120 Hz with your console either.

Therefore, to take full advantage of this new connection, it is necessary to use an HDMI 2.1 cable, which is commercially called Ultra HD Speed ​​Cable. Only these cables guarantee a bandwidth of 48 Gps, necessary to reach the 8K resolution and the refresh rate of 120 Hz.

When buying an HDMI cable, look at the box or label:buy HDMI cable

Both the box and the cable are printed with the trade name: Ultra High Speed ​​HDMI Cable.

You should include the maximum resolutions and refresh rates, as well as the transfer rate, on the label or package.

Some brands also include a QR code that can be scanned with the official HDMI app for full specifications.

These cables are Category 3 cables and can be active or passive, as desired by the manufacturer.

If you want to get the most out of your HDMI 2.1 TV or monitor, you should use such a cable with devices that are HDMI 2.1 (consoles, graphics cards, video players, etc.).

Do I need a TV with HDMI 2.1?

We have seen all the features of the new HDMI 2.1 standard. The last question we still have to answer is: Is it worth buying a TV with HDMI 2.1 if they are more expensive?

The answer depends on your priorities.

If you are only going to watch Netflix in 4K or play games with the Nintendo Switch, it is unnecessary. If you want dynamic HDR as standard and, especially, you will connect a new generation console or a gaming PC, then HDMI 2.1 becomes a must.

Playing flawlessly on the screen, with the image completely smooth and with lower latency, is a significant improvement.

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