HDMI 2.1: What You Need to Know

15 Minutes with HDMI Forum Chairman Chris Pasqualino

When HDMI hit the scene in 2003 it was welcomed as a godsend, enabling enthusiasts to replace a rat’s nest of audio and video cables with a single connection. The specification has evolved steadily over the years to keep pace with the ever-changing AV landscape and encountered a few bumps along the way. In January, the HDMI Forum announced Version 2.1, a forward-looking upgrade of the current HDMI 2.0b spec. We recently caught up with HDMI Forum Chairman Chris Pasqualino to learn about the implications of HDMI 2.1 now and in the future.

S&V: Let’s start with some background on the Forum and the role it plays in the ongoing evolution of the HDMI audio/video interface, the de facto connection standard for AV gear.
Chris Pasqualino: The HDMI founders announced the formation of the HDMI Forum in 2011 with the mission to foster broader industry participation in the development of future versions of the HDMI specification. The Forum is an open trade association comprised of the world's leading manufacturers of consumer electronics, personal computers, mobile devices, cables, and component. In September of 2013 we released Version 2.0 of the HDMI Specification on behalf of the HDMI Forum and its subsequent versions, 2.0a and 2.0b. At CES 2017, we announced the upcoming release of Version 2.1.

S&V: Some astonishing statistics were shared at the CES press conference: 6 billion HDMI-enabled devices have shipped since 2003 and more than 750 million HDMI devices were expected to ship in 2016. Huge numbers. How many versions and updates of HDMI have there been since the beginning, and is it fair to say that 2.1 represents the biggest leap in capabilities to date?
CP: The HDMI 1.0 spec was released back in 2002 and there have been seven major releases with a number of secondary version updates. Many of the versions introduced key features such as support for advanced audio formats and higher video resolutions, advanced color spaces, and device control. They also defined new HDMI cable categories. For the HDMI Forum, Version 2.1 is the biggest step in new features since we introduced HDMI 2.0 in 2013.

S&V: HDMI 2.1 promises significant upgrades in several areas. Can you walk us through each upgrade and its key benefits, starting with video?
CP: For video there is support for higher resolutions and frame rates—including 8K60 and 4K120—that provide a greater level of immersive viewing and smooth fast-action images. The spec also supports 10K resolution, which will serve the PC and commercial AV markets. But as more high dynamic range (HDR) content comes to market, our most compelling video feature is the continuing support for HDR, which now enables Dynamic HDR and various HDR technology implementations.

We also are introducing a new 48G cable to enable bandwidths up to 48 Gbps and support for the full suite of 2.1 features. HDMI 2.1 uses existing connectors and is backwards compatible with all existing HDMI devices.

Our Game Mode VRR, for variable refresh rates, frees gaming devices from the restrictions of device refresh rates, enabling graphic frames to be processed and sent as soon as they are ready and eliminating frame tearing, stutter, and lag.

eARC (Enhanced Audio Return Channel) supports the latest audio formats, including object-based audio, such as Dolby Atmos and DTS:X.

S&V: What key audio advances and benefits does 2.1 bring to the table?
CP: The eARC feature, which stands for Enhanced Audio Return Channel, is an augmented version of HDMI’s current ARC. It provides the easiest way for many consumers to enjoy high-bit-rate audio and advanced audio formats—including object-based audio [such as Dolby Atmos and DTS:X]—because they will be able to deliver those formats via an eARC-enabled HDMI port on their TV. eARC also provides support for the TV’s over-the-air tuner, streaming apps received by the TV, and audio from HDMI sources connected to the TV.

A key advantage of eARC is that it enables a TV-centric living room or home theater configuration that can provide a more seamless experience. Today, an AV receiver—or a similar repeater device—is necessary to extract high quality audio from an HDMI link, while the video is processed and passed through to the TV. The user may have to switch inputs on both the TV and an audio device to find the source of their content, and content sourced within the TV and from TV inputs is frequently limited to stereo or, in the best case, one of a very small number of compressed formats.

With eARC, it will be possible to connect all sources through the TV and send audio to the sound system completely uncompromised. Furthermore, eARC will make possible a new breed of audio-only receivers that will yield greater value and ease-of-use by eliminating a video subsystem. So, in theory anyway, overall video and audio performance will improve with eARC.


Philt56's picture

ARC does not work with my LG OLED tv and NAD receiver. When asked for support help, both companies basically said the ARC standard was so open to interpretation that they couldn't help solve the problem. ARC worked ok with the same receiver and my Sony LED tv, although even that was flaky at times.

What can be done in 2.1 specs for ARC and CEC to ensure that different manufacturers' devices interoperate correctly and consistently with each other?

Deus02's picture

I fully agree. I was using ARC between my LG 4K set and my Yamaha Pre-Pro and all of a sudden one day it stopped working never to do so again. I could never find out exactly why from either company. Ultimately, when using the monitor as the source for programming (i.e. Netflix, Youtube etc.) it was better to just use the audio out from the television(analog/optical) and plug it into a separate input on my Pre-Pro and program my remote accordingly. I have never had a problem since.

Incidentally, since the introduction of HDMI and the constant moving target that it has been since that introduction, with the myriad of equipment from different generations and the questionable reliability of the connectivity during this period, even with the reduction in cable requirements, I would take issue with the description of HDMI being a "godsend".

Philt56's picture

One time I was not getting any sound, finally I looked at my receivers display and it said ARC, but no sound was playing! The NAD automatically switches to ARC when it detects it.

drny's picture

I've read various articles on HDMI 2.1 from a number of industry sources.
S&V article falls in the sweet spot. Plenty of explanation of the technological upgrades without "talking above our head".
Much apprecaited.

Billy's picture

Had a comment here earlier, it has disappeared, hmmmm? People, did I say something wrong? All I said was that HDMI as a single cable is awesome, but the DRM aspects of it make it almost unworkable in some instances. I have a horrible problem with longer distances. If Car 6 can run HD 200 or more feet, why not HDMI? Must be the "handshake" BS. I have many TVs, all HCMI equipped sent through amps, splinters, etc. I forever, it seems, need to be turning off and on TVs, unplugging HDMIs and re plugging them, etc...just to get them to work. I understand Hollywoods trouble with piracy, truly I do. If it were my creative work, I would want to be paid too. I do not pirate, all my stuff is legal as can be, but yet I must suffer because of piracy? HDMI has done NOTHING to stop off shore pirates, NOTHING. Why not make HDMI, DRM free, and let the connection shine? Hollywood could lower the price of their goods and make it up in volume. Worked for Henry Ford, why not? The average person, even the low lifes that file share, would be stupid to try and steal a low quality product, when high quality goods were available at a reasonable price. Okay, off my soap box. (see, just had a 2 second power outage last night, and had to reset all my HDMI connections in the whole house, not in the best mood)

denslayer's picture