HDMI 2.0 and its younger sibling HDMI 2.0b are still the most common versions in the market. In 2021 the industry has been rolling out out the latest and greatest release: HDMI 2.1. What does HDMI 2.1 do, and why do you need it?
1. Better image
HDMI 2.1 allows for higher resolutions at higher frame rates than before. HDMI 2.0b offers a maximum of 4K resolution at a maximum frame rate of 60Hz. HDMI 2.1 allows for 4K at 120Hz, 8K at 60Hz, and right up to 10K resolution for industrial and commercial applications. This is great news for the film industry. The HDMI organization says some Hollywood directors are eager to move to 120Hz native filming as they look to deliver high frame rate content to the screen.
High-dynamic range is already the best improvement to TV picture quality since 1080p HD, but it can be even better. Some reviewers consider Dolby’s version of HDR, Dolby Vision, superior to other formats because 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 problem with Dolby Vision is that it is a proprietary technology and not every manufacturer wants to pay licensing fees to use it. HDMI 2.1 brings dynamic HDR performance, including the dynamic version of HDR10, known as HDR10+.
You may think: isn’t HDR10+ already possible using HDMI 2.0b? Technically, yes, but it’s not an officially supported technology when run over HDMI 2.0b. HDMI 2.1 makes it official and as such reliable.
2. Better audio
The Audio Return Channel (ARC) is an HDMI 2.0b feature that allows for bidirectional audio 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, resulting in “lossy,” lower-quality audio.
With HDMI 2.1 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!
Currently, it can be a hassle to sync 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, and the result of that mismatch is sound that 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 the time.
3. Better gaming
Let's get back to the fact that HDMI 2.1 allows for 4K at 120Hz and 8K at 60Hz. This is great news for gamers, as higher frame rates mean smoother, better-looking games.
Just as important from a gaming perspective, HDMI 2.1 allows for variable frame rates. Modern PC and console games do not use a single frame rate throughout the game. It varies — sometimes by quite a lot — depending on the complexity of the scene. When frame rates drop or speed up, there is a mismatch between what the game is providing and what the TV or monitor is set to display. To compensate, the display 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 rate transport 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 virtual reality — VR — headset). Again, this is great for gamers, who will notice much less lag, especially those who like fast-action, first-person shooters. VR users will benefit from an equally reduced time between movements and the world presented through their goggles.
Oh, and you know that blank, black screen you sometimes get when you switch sources or from games to streaming apps? It was fun while it lasted … but that’s going away forever.
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.
So there you have it. 3 reasons why HDMI 2.1 is what you need to future proof any AV installation.