With next-gen consoles arriving in late 2020 and NVIDIA̵
Higher bandwidth, more pixels
Most displays on the market currently support the HDMI 2.0 standard with a bandwidth limit of 18 Gbit / s. This is sufficient to transmit an uncompressed 4K signal at 60 frames per second and up to eight bits of color. This is sufficient for the vast majority of uses, including watching UHD Blu-rays or playing games on an Xbox One X.
HDMI 2.1 is the next step forward for the standard and supports an uncompressed 8K signal at 60 frames per second in 12-bit color. This is achieved with a bandwidth throughput of 48 Gbit / s. With Display Stream Compression (DSC), HDMI 2.1 can transmit a 10K signal at 120 frames per second in 12 bits.
Some implementations of HDMI 2.1 use ports that only reach around 40 Gbps. This is enough to process a 4K signal at 120 frames per second in 10-bit color. This is also enough to take full advantage of the 10-bit panels of consumer television sets.
High-end PC gamers tempted by NVIDIA’s new 30-series cards will be pleased to learn that the company has confirmed future 10-bit support. This means it doesn’t matter if your TV lacks the full 48Gbps specification.
Currently, HDMI 2.1 is primarily aimed at gamers who are stepping onto the next-generation console or graphics card train. Both the Xbox Series X and the PlayStation 5 support a 4K resolution of 120 frames per second. This requires the implementation of the HDMI 2.1 standard.
If your television does not support HDMI 2.1, you will have to make do with a 4K signal that only runs at (!) 60 frames per second. The majority of titles in the latest generation of consoles ran at 30 frames per second, so it remains to be seen how much deal-breaker this will be.
HDMI 2.1 is so new that NVIDIA only has three new Series 30 cards in the pipeline that support the standard. The earlier RTX 2000 and GTX 1000 series cards are not HDMI 2.1 compatible. Many TV manufacturers, including Sony, haven’t included HDMI 2.1 in their top-tier displays yet.
We assume that the HDMI 2.1 standard will really catch on in 2021. However, it will be a few years before we see widespread adoption in budget displays.
Dynamic HDR support
With so much available bandwidth, there is also more space in the pipes for raw data. HDR stands for High Dynamic Range and enables a wider range of colors in content such as films and games. Older HDR standards like HDR10 only support static metadata. However, the newer formats HDR10 + and Dolby Vision allow dynamic metadata per scene or frame.
Dynamic HDR gives a television more information about what to do with the received signal. Instead of just reading a guide for an entire movie, the TV’s dynamic metadata is constantly updated to optimize the image on the screen so that it looks its best.
While every HDR-capable TV supports HDR10 with its static metadata, dynamic HDR is another beast. The most widely used format is Dolby Vision. It is preferred by hardware manufacturers like LG, Sony, Panasonic, and Philips. Samsung is going all-in on the less popular HDR10 +, which is also an open format (Dolby Vision, as the name suggests, is proprietary).
It’s important to note that you don’t need an HDMI 2.1 device to display HDR10 + and Dolby Vision – at least not at current 4K resolutions. If your TV supports it, Dolby Vision content will be streamed from Netflix without any problems.
In the future, however, the HDMI 2.1 standard will ensure that sufficient bandwidth will be available for both metadata and high-resolution signals with high frame rates.
We don’t yet know how the PlayStation 5 or Xbox Series X will implement HDR, but they will likely be the main field of evidence for dynamic HDR over HDMI for the next several years.
Variable update rate (VRR)
The refresh rate of a television is the number of times the control panel is updated per second. This is measured in Hertz and is closely tied to the frame rate. If the two are out of sync, you get an effect called “screen crack”. This is caused by the display trying to show more than one picture at a time when the console or PC is not ready.
By adjusting the refresh rate of the display to match the frame rate of your console or PC, you can effectively avoid screen tearing without sacrificing performance. Companies like NVIDIA and AMD have their own methods of dealing with screen tears known as G-Sync and FreeSync, respectively.
However, the HDMI 2.1 standard also has its own standalone solution called the HDMI Variable Refresh Rate (VRR). Microsoft has confirmed that the Xbox Series X will support this feature, and the PlayStation 5 is expected to do so too, as HDMI 2.1 needs to deliver 4K at 120Hz.
For the best possible next-generation console experience, HDMI VRR is a must. If you’re a PC gamer, NVIDIA and AMD are unlikely to ditch their existing technologies in favor of HDMI VRR. This means that you will still need to pair your graphics card with your monitor.
Auto Low Latency Mode (ALLM)
Another benefit for next-generation console gamers is the Auto Low Latency Mode (ALLM). Most televisions now have all sorts of additional processing to smooth motion, improve picture quality, and even improve audio quality. While some of this is appreciated when watching TV and movies, it introduces latency (lag) for gamers.
The game mode is intended for this. You can switch to it anytime you want the fastest possible response time from your TV. This is especially useful for games that require quick and precise reflexes. The only problem is that many TVs require that you toggle game mode on and off manually.
ALLM makes this superfluous. When your HDMI 2.1 Compatible TV detects that you are using a supported console, ALLM will disable any additional processing that may cause delays. You don’t have to do anything to activate it – it’s built into the HDMI standard.
Microsoft has confirmed ALLM support for the Xbox Series X, but not a word from Sony yet.
Fast frame transport (QFT)
Quick Frame Transport is another feature for gamers that, in conjunction with ALLM, offers a more responsive gaming experience. The function prioritizes video images in order to keep latency as low as possible.
If you want to use this function, make sure that intermediate devices such as a surround sound receiver are also compatible. This ensures that all of your devices work together to ensure a smooth and responsive experience. If you route your console through a receiver designed for HDMI 2.0 only, you won’t benefit from QFT even if your TV and console support it.
Quick Media Switching (QMS)
Have you ever noticed your screen go black right before watching a video or trailer? This is because the display adjusts its refresh rate based on the content you are about to watch. Since different content uses different frame rates, your display must be synchronized with this, hence the short blackout.
Sometimes this can cause you to miss the first few seconds of a video. However, some content providers are delaying playback to accommodate the change. Assuming the resolution of whatever you’re watching stays the same, Quick Media Switching (QMS) eliminates the power outage caused by changes in the refresh rate.
This allows you to view content with different frame rates one after the other without blackout. The feature uses HDMI VRR to smoothly switch from one refresh rate to the next.
Enhanced Audio Return Channel (eARC)
ARC stands for Audio Return Channel. You can send audio to your soundbar or surround receiver via HDMI without an additional optical audio cable. Whether you’re watching Netflix, playing a game on a console, or watching a Blu-ray, ARC makes sure that the audio is delivered to the correct output.
The Enhanced Audio Return Channel (eARC) is part of the HDMI 2.1 standard. With the additional bandwidth available in HDMI 2.1, eARC can transmit uncompressed 5.1, 7.1 and object-based audio at high bit rates and up to 192 kHz in 24-bit resolution. It does this with an audio bandwidth of 37 Mbit / s, compared to less than 1 Mbit / s over regular ARC.
If you want to transmit a Dolby Atmos signal over HDMI, you need eARC. There are some other improvements as well, like the correct correct lip sync correction, better device detection and a dedicated eARC data channel.
Do HDMI 2.1 devices require special cables?
Because HDMI 2.1 has higher bandwidth throughput, you need HDMI 2.1-compatible cables to take advantage of the new features. The HDMI license administrator has approved a new “Ultra High Speed” label for these cables.
Any device that uses HDMI 2.1, such as a game console or Blu-ray player, should have a cable in the box. Plus, buying an HDMI cable can help you avoid the overpriced premium sort.
HDMI 2.1 is mostly for gamers (for now)
Most people don’t need HDMI 2.1 right now. The improved standard will primarily benefit gamers who buy consoles or next-generation graphics cards and want functions such as HDMI VRR and ALLM. Outside of eARC, the new standard offers home theater enthusiasts few benefits.
Microsoft has announced the multiplayer part of Halo Infinite will ruin in native 4K at 120 frames per second, but the game has been delayed until 2021. We’ll have to wait and see if console titles achieve this lofty goal.