Just when you thought you had a handle on HDMI 2.1 and its many benefits to gamers, among other video and audio entertainment enthusiasts, along comes HDMI 2.1a (the “a” stands for “aaaargh!” as many industry folks joke). Interestingly, it turns out, there are no fully standardized specifications for HDMI in regards to product implementation, so clear messaging on the part of hardware and accessory manufacturers is essential in terms of helping dealers and consumers get the appropriate hardware or cable.
“Just promoting a product as an HDMI 2.1 product doesn’t mean that all the spec’s features are supported,” says Brad Bramy, VP of Marketing and Operations at HDMI Licensing Administrator. “A manufacturer can choose from several HDMI features to incorporate into their product, but it is not obligated to support all. It’s just obligated to support at least one and state which one it is.” The reasoning behind this is to offer manufacturers the flexibility to focus on a product’s market and price point, per Bramy.
“There are, of course, basic requirements that are necessary jus for basic functionality, interoperability, and backward compatibility,” says Bramy, “but the features that people are most aware of and that the manufacturers promote are the optional ones.” The big leap for HDMI 2.1 is that it is capable of handling a bandwidth of 48 Gbps, which is a huge leap from the 18 Gbps, which translates to uncompressed support for 8K video at 60 Hz and 4K at 120 Hz. This means it can not only handle 8K video, but also high-resolution 4K gaming at 120 Hz on TVs (not just computer monitors). which makes it ideal for the high-resolution action of gaming, but also movies and TV. So that’s a common basic capability of HDMI 2.1, but the features that are promoted depend on a product’s function – stuff like variable refresh rate, low-latency mode, and dynamic HDR. The bottom line, according to Bramy, is that dealers and consumers alike must look at all the specs to make sure the products they are purchasing are capable of executing the features they want. HDMI 2.1 specification in and of itself won’t necessarily tell the whole story.
As for HDMI 2.1a, Bramy says it’s a fairly minor upgrade that introduces a capability called source-based tone-mapping, which essentially enables a source to send a video signal that takes full advantage of a specific display’s HDR capability. In other words, the HDR processing is done on, say, the TV side, which just enables a deeper and more robust set of video optimization.