The Verge reports that HDMI 2.1a is supposedly getting announced at CES 2022 and will succeed the existing HDMI 2.1 standard. On paper, this sounds… fine. It’s just a new spec in a long line of specs that barely hold any coherence. At the fundamental level, HDMI 2.1a is the same as HDMI 2.1 but it adds one major new HDR feature that actually makes its existence exciting.
Source-Based Tone Mapping
That new feature is Source-Based Tone Mapping (SBTM). As the name suggests, this feature will essentially offload some of the HDR tone mapping to your display’s source, like a computer, and lets that source do most of the heavy-lifting. This makes it so that your display doesn’t have to calibrate the content itself, neither do you have to manually go into settings and fiddle around until your find the perfect look. Before we move on, we first have to understand the importance of tone mapping itself. Whenever you’re playing SDR content on an HDR display or vice-versa, the content needs to be tone-mapped to that dynamic range. Improper tone mapping leads to harsh and/or unpleasant visuals. For example, if you’ve ever tried to play HDR video on an SDR display, you’ll notice that the video looks dim and dull. That’s because your content source isn’t being properly tone-mapped for the SDR display. SBTM will allow for potentially better HDR visuals by optimizing the content being passed on to the display. This has various use cases where such a feature could really come in clutch like for video editing where the actual editor itself is SDR but the preview and thumbnail are HDR. Apart from that, the other notable upgrade the new HDMI 2.1a spec will bring forth is proper 10K resolution support at 120Hz. The HDMI Forum (one of the two organizations governing the HDMI protocol) has stated that manufacturers will be able to add SBTM via a firmware update to their displays/sources which will make it fall in line with the HDMI 2.1a spec. However, that rarely ever happens in the industry and a new feature remains a novelty you can only get if you actually purchase a device that has it out of the box. Which, in this case, means no over-the-air HDMI 2.1a for you.
The confusing mess
That was all of the good part. Don’t get me wrong; there isn’t necessarily something wrong with the new spec as it doesn’t add any divisive features or take away a useful one. It’s just that the very thing that’s supposed to make HDMI 2.1a, well, HDMI 2.1a is an optional feature, one that isn’t mandatory for the standard. Now, you may be asking how does any of that make sense? Let me explain. The HDMI Forum and HDMI Licensing Administrator are extremely contemporary folk. In other words, the HDMI standards they set out are so that whatever the latest standard of HDMI is, that’s the one that every single new display with HDMI will be getting. HDMI 2.0, the predecessor to HDMI 2.1 does not technically exist anymore according to the organizations as HDMI 2.0 compliant displays are all folded into HDMI 2.1 just because that’s the latest standard. Therefore, the upcoming HDMI 2.1a standard will phase out the current 2.1 spec, even if the display in question doesn’t support SBTM. Any new HDMI display with new HDMI ports will technically be HDMI 2.1 because that’s what the current standard is. The HDMI forum says this is done to give manufacturers flexibility to adequately diversify their product portfolio by offering features according to the price. A entry-level $300 HDMI 2.1a TV won’t have 8K support, but it would still have HDMI 2.1a ports and stay up to date with the current spec. The HDMI Forum further highlights that they push manufacturers to detail every single spec for this very reason. So that the customer buying the TV can know exactly what they’re getting. Even if the a $300 TV has HDMI 2.1a ports, it would need to outline the exact capabilities of that and the device itself in order to stay on the Forum’s good side. If the customer needs to tediously check the fine print then what even is the purpose of having the standards in the first place? However, TFTCentral‘s recent report clearly shows that this technique of the HDMI Forum hardly works. Manufactures still label new TVs as HDMI 2.0 or 1.4 based on the capabilities of the device, despite that technically being the wrong thing to do. It’s really telling when a large business is more clear at defining standards than a literal organization who’s sole purpose is to standardize HDMI and make it easy for everyone to understand it. The real issue starts to occur when a manufacturer labels HDMI ports that don’t have any HDMI 2.1(a) features as such, and the customers just sit and watch like fools because that actually would come under the rules of the organization. You start to see how this whole thing is such a confusing mess? We’re honestly lucky that most TV manufacturers are adamant to listen to the HDMI Forum’s strange spec nomenclature, and instead just label the ports for what they actually support, even if it’s against the Forum’s rules. The HDMI Forum has also reiterated that this is how HDMI standardization has always worked, but then again, might as well just print the entire spec list of the TV in place of the HDMI spec logo if they are all essentially just a mumbo-jumbo of each other? As it stands right now, HDMI 2.1a is walking into the same ring and will become the new standard after it launches at CES 2022 along with a myriad of new TVs. I just hope manufacturers keep resisting the HDMI Forum’s weird standardization and just stick to common sense for the better. Even though, it seems like this report might be legit, especially considering the source, take it with a grain of salt and wait for the official announcement before making a purchase.
