There's no question. HDMI has been a great convenience for the consumer. Aside from being a high bandwidth connection that enables high resolution video and lossless audio, it's a lot simpler to use than the old days where you needed three chords for an HD picture and then up to six more for surround sound. But, that doesn't mean that it doesn't have its issues. Some of which are a result of its digital design.
Unlike old school, analog AV connections, digital protocols, like HDMI require a lot more processing, introducing complexity and more potential points of failure. One such issue that's been making headlines recently has to do with new HDMI 2.1 connections.
In a nutshell, it's an incredibly fast revision that allows 8K 60 or 4k 120 Hertz pictures, dynamic HDR and even variable refresh rate support for gamers to help cut down on ugly screen tearing. Sounds pretty good, right?
Well, it turns out that a widespread HDMI 2.1 chip set is causing lots of headaches for early adopters. You see, although tons of companies make HDMI components, many of them source the actual chip sets that run them from the same places. In this case, AV receivers from Denon, Yamaha, and Marantz have all been using a faulty HDMI 2.1 chip from Panasonic. The problem is that when a device is set to 4k 120 Hertz mode and connected to an HDMI 2.1 port on one of these receivers, the video signal won't be passed through to your display and no sound will come out of the speakers connected to the receiver. So congratulations, your festival of high resolution video and immersive sound just amounted to a whole lot of nothing.
This has been especially disappointing for folks who bought an Xbox Series X, PlayStation 5 or Nvidia RTX 3000 Series graphics card as all of these devices boasted 4k 120 Hertz support as big selling points.
The only workarounds right now then are either to connect your gadget directly to your display and use HDMI audio return channel to send the audio signal back to your receiver, or just settle for 4k 60 mode until a patch is issued. That is assuming that the problem can even be fixed through software.
Although the companies involved are working on a solution, it appears that they don't even know exactly what the problem is. But hold on a second, HDMI is a standard meaning all the manufacturers have to do is build a product according to the spec, right? How has this broken? Well, one potential trouble spot is the way that HDMI handles sending and receiving non-video information. This includes identifiers that are exchanged between two connected devices, so that one device knows what's connected it and what it can do. It also includes plug and play features and HDCP, which is HDMI's content protection system designed to counter copyright infringement.
All of these features are handled by part of the connection that is vulnerable to electrical interference from other parts of the system making it a common source of problems. And of course, if you've ever seen a blank or snowy display over HDMI, there's a good chance that's because of the HDCP handshaking procedure, that's used to ensure that connected devices are compliant with copy protection. It ain't perfect and often necessitates a power cycle.
Additionally, packing so many features into one cable not only means that it can be a little hard to switch between inputs, which is part of what a receiver has to do, but it also means that it is basically impossible to test every configuration of different HDMI compatible hardware that's out there. It's similar to how sometimes PC components just don't play nicely with each other, even though they're all supposed to be compliant with certain standards. The nuances and idiosyncrasies of each individual component can affect a standard protocol in unforeseen ways, which is possibly part of what's going on with the current HDMI 2.1 fiasco.
Now we're not saying that any specific issue we just discussed is the actual culprit we're gonna have to wait possibly into next year to find out. In the meantime, hopefully we can all settle for 4k 60 or 1080p 120.