HDMI 2.1a: how the new version is different that adds even more confusion between the HDMI 2.1 connectors

Buy a TV with HDMI 2.1 does not guarantee that you can take advantage of all the advantages of the new consoles PlayStation 5, Xbox Series X or the latest graphics cards. Now, as if the above were not enough, a new version of the video standard is appearing on the horizon: it is HDMI 2.1a.

It’s just that the way TV manufacturers are implementing HDMI specs is really confusing. And, unfortunately, this is not a whim of the companies, but a series of guidelines established by HDMI Licensing Administrator, Inc., the organization that licenses and monitors the video standard.

The version and feature mess

As HDMI is not an open standard, manufacturers interested in adopting it must have a license, and this comes with a series of very strict rules. One of them states that new certified products must have the latest version. This is because older versions are superseded and are no longer available.

However, (and here the problems begin) manufacturers are not required to implement all the functions of a version for it to be considered compatible. For example, the whole (yes, the whole) of the new features of HDMI 2.1 they are completely optional today.

This means that feature support may vary from device to device, even within the same HDMI version. You can have an HDMI 2.1 connector, but it may not support any of the features that were released with that version, that is, it could be a kind of HDMI 2.0 in disguise.

Features

HDMI 2.0 – 2.0b

HDMI 2.1

Full HD Blu-ray Disc Y HD DVD video

Yes

Yes

Consumer Electronic Control (CEC)

Yes

Yes

DVD-Audio

Yes

Yes

Super Audio CD (DSD)

Yes

Yes

Auto lip-sync

Yes

Yes

Dolby TrueHD / DTS-HD Master Audio bitstream capable

Yes

Yes

Updated list of CEC commands

Yes

Yes

3D video

Yes

Yes

Ethernet (100 Mbit/s)

Yes

Yes

Audio return channel (ARC)

Yes

Yes

4 audio streams

Yes

Yes

2 video streams (Dual View)

Yes

Yes

Perceptual quantizer (PQ) HDR OETF (SMPTE ST 2084)

Yes

Yes

Hybrid log–gamma (HLG) HDR OETF

Yes

Yes

Static HDR metadata (SMPTE ST 2086)

Yes

Yes

Dynamic HDR metadata (SMPTE ST 2094)

NO

Optional

Enhanced audio return channel (eARC)

NO

Optional

Variable Refresh Rate (VRR)

NO

Optional

Quick Media Switching (QMS)

NO

Optional

Quick Frame Transport (QFT)

NO

Optional

Auto Low Latency Mode (ALLM)

NO

Optional

Display Stream Compression (DSC)

NO

Optional

What we explain in detail a few days ago, the Xiaomi Fast LCD Monitor is the clearest example of this situation. The device claims that it has two HDMI 2.1 ports and, although no one can deny it, these connectors actually offer HDMI 2.0 features.

However, this same scenario will be repeated with the arrival of HDMI 2.1a. Once the specification is available it will replace HDMI 2.1. The new televisions will come, by default, with the “label” of the new version, although the only function associated with it may not be included by many manufacturers.

HDMI 2.1a se centra en HDR

HDMI 2.1a will be a minor update, but it will come with an interesting feature that seeks to balance the HDR content playback experience in all possible scenarios. This is source-based tone mapping, also known as SBTM, for its acronym in English.

Sbtm Combo Large Crop

This feature will add additional capabilities to existing dynamic range display systems and will render some of the content on the source device. delivering optimized images to target screens and avoiding the user having to perform manual calibrations.

Also, instead of adopting a fixed set of color and brightness ranges, SBTM it can be dynamically adapted. As a consequence, will offer better results in combined content reproductions. For example, when video thumbnails are HDR and other on-screen items are presented in SDR.

As pointed out The Verge, HDMI 2.1a will be presented at the CES 2022. The organization in charge of the standard will allow devices sold with HDMI 2.1 to enjoy the benefits of HDMI 2.1a. Of course, for this to happen the manufacturers of the devices should allow a firmware update.

With an eye on the fine print

The present salad of functions, HDMI 2.0, HDMI 2.1 and 2.1a leaves us a clear lesson: We cannot rely on the connector version when buying a new TV or monitor.

But nevertheless, the standard adoption agreement forces manufacturers to list which features the connectors support included in their devices, in addition to indicating the version of the specification in question.

In that sense we will have to take the trouble to verify if the HDMI functions that interest us are supported, although the information may be hidden behind an asterisk

and in small print. Image |

HDMI Licensing Administrator

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HDMI 2.1a: how the new version is different that adds even more confusion between the HDMI 2.1 connectors