Sunday, July 24, 2022

Connecting the Dots - Part 2 - HDMI

For Part 2 of my "Connecting the Dots" series, I'll be discussing HDMI, both the underlying technology and the cable types we use to connect HDMI-enabled devices. If you've ever wondered what the different versions of HDMI mean and which cables to use to ensure that you get the best multimedia experience with your equipment, this post is for you. Let's get started!


HDMI - High-Definition Multimedia Interface


If you've owned a TV or multimedia device of any kind over the last 15 years or so (and I'm betting you have), you've probably heard the term HDMI, whether in reference to your device's features or the cables used to connect your devices.

Simply put, HDMI is the standard interface type used to connect multimedia devices (much like USB is the standard for connecting computing devices). HDMI devices come in 4 primary versions, and there are 4 types of HDMI cables. 

Sounds straightforward, right? Unfortunately, our friends in the TV industry managed to make what was supposed to be a simple standard somewhat complicated, but hopefully I can clear up some of the confusion in this post.

Not pronounced "Hedemi"

HDMI Versions


HDMI 1.0 was released in December 2002 as a new standard interface type for transmitting both audio and video signals; this was a major innovation, as most multimedia transmissions interfaces up to that point transmitted either video or audio, not both. The promise of HDMI was that it would make multimedia connections simpler by providing a single connection that could handle a variety of signal types.

Despite this promise, HDMI didn't see widespread adoption by consumer electronics until the rise of high-definition TVs in the later 2000s. By then, the most common HDMI version was HDMI 1.4.


HDMI 1.4b


Released in June 2009, pretty much every TV manufactured since 2010 has supported HDMI 1.4b. Now the oldest of the HDMI versions still in production, HDMI 1.4b helped kickstart the rise of high-definition TVs by supporting the transmission of video content up to a resolution of 1080p @ 120Hz, 4k @ 24Hz, and surround sound (via a feature called Audio Return Channel, or ARC).

While virtually all new TVs manufactured today employ newer versions of HDMI, many older TVs in use today are still running strong on HDMI 1.4b.


HDMI 2.0


Introduced in September 2013, HDMI 2.0 added support for video content resolutions up to 4k @ 60Hz, 32-channel audio content, and an enhanced color space called Rec. 2020. HDMI 2.0 reached large-scale adoption in the 2014 model year and remained the dominant HDMI version through 2015.

In April 2015, and update for HDMI 2.0, called HDMI 2.0a, was released. This version of HDMI added support for High Dynamic Range (HDR) content (which is all the rage with TVs today), as well as an upgrade for ARC called eARC (Enhanced Audio Return Channel). HDMI 2.0a was the flagship HDMI standard for the 2016-2018 model years. 

This implementation of HDR technology was further refined with the release of HDMI 2.0b in March 2016, which added support for HLG (Hybrid Log-Gamma). Most TVs manufactured in the 2019-2021 model years support up to HDMI 2.0b.


HDMI 2.1


In January 2017, HDMI 2.1 was released. The most significant revision for the HDMI standard since it was first introduced, HDMI 2.1 adds support for video resolutions of 4k & 8k @ 120Hz, object-based and high-definition audio formats, and gaming features such as Variable Refresh Rate (VRR) and Auto Low Latency Mode (ALLM).

Because HDMI 2.1 is such a major change to the HDMI specification, adoption of the new version has been slow. Though officially released in early 2017, only starting in the 2022 model year has a wide range of TVs supported this new version.


HDMI Cables


Like the HDMI spec itself, HDMI cables come in several different flavors, which are:

  • Standard
  • High Speed
  • Premium High Speed
  • Ultra High Speed

While most HDMI cables look about the same, they come in several different types.

Now, it's worth noting that each HDMI cable type doesn't necessarily correspond to a particular version of HDMI. Instead, the primary difference between the different cable type is how much bandwidth each cable provides. Newer versions of HDMI require more bandwidth, which is why they may require certain cable types. I'll explain in more detail below.


Standard HDMI Cable


The original HDMI cable, Standard HDMI cables have about 5 Gb/s of bandwidth, which is sufficient to support up to HDMI 1.2. An older spec, Standard HDMI cables are no longer widely manufactured and have largely been replaced by High Speed HDMI cables.


High Speed HDMI Cable


The most common HDMI cable available today, High Speed HDMI cables have about 10 Gb/s of bandwidth, which supports all HDMI versions up through HDMI 2.0b. Because of their ubiquity, these cables are quite affordable and can be found at retailers like Amazon for pennies on the dollar.


Premium High Speed HDMI Cable


Premium High Speed HDMI cables have 18 Gb/s of bandwidth and are additionally certified by the HDMI Forum to meet standards of durability and EMI (electromagnetic interference) shielding. 

The label affixed to all Premium High Speed HDMI cables. The QR code can be scanned for authentication.

The Premium High Speed spec for HDMI cables was created by the HDMI Forum (the body that regulates HDMI standards) in response to the appearance of cheap High Speed HDMI cables that eventually came to saturate the market. The concern was that some of these cheaper High Speed HDMI cables were of suspect build quality, and manufacturers of high-quality HDMI cables wanted a way to distinguish their cables from cheaper ones. Thus, the Premium High Speed HDMI cable was born, with each one carrying a scannable QR code on the label that can be used for authentication.

While Premium High Speed HDMI cables don't support any more versions or features of HDMI than regular High Speed HDMI cables, they are intended to offer the consumer assurance of quality that had been lacking in the marketplace.


Ultra High Speed HDMI Cable


Ultra High Speed HDMI cables are the newest HDMI cables, sporting a bandwidth of 48 Gb/s, sufficient to support the full HDMI 2.1 spec. 

If you see this label, know that you're getting the best (and most expensive) HDMI cable available.

Ultra High Speed HDMI cables also adhere to the same physical standards as Premium High Speed HDMI cables and offer QR code verification. Also, be aware that these cables are more expensive, averaging about $10/foot (though that will likely lower over time).


What I learned


Years ago, a tech journalist explained that low-cost High Speed HDMI cables were sufficient for connecting all HDMI-enabled devices, and that more expensive HDMI cables were a waste of money. For the most part, he was right; after reading his piece, I proceeded to equip all my devices with cheap High Speed HDMI cables purchased from Amazon, and I never had much cause to revisit that decision.

However, with the emergence of new HDMI features as part of the HDMI 2.0 and 2.1 specs, I wanted to check again to make sure my old cables were still up to the task. Fortunately, I found that they are, though that will change as more HDMI 2.1 devices find their way into my home over the next few years.


What you can apply


The good news here is that picking the right HDMI cable is actually pretty straightforward. 

First off, Standard HDMI cables aren't really around anymore, so you don't have to worry about them at all.

Most devices today work fine with High Speed HDMI cables, since they're likely using HDMI 2.0b or earlier. Additionally, High Speed HDMI cables are abundant (and cheap), so you shouldn't have much trouble obtaining them.

Premium High Speed HDMI cables are only really necessary in environments where cable durability or EMI shielding is a requirement, such as if you're running the cable through a wall or in an area with high EMI (very rare).

Ultra High Speed HDMI cables are required only if you're connecting two HDMI 2.1-enabled devices to one another and want the full suite of features the spec offers. Most HDMI 2.1 features are gaming-centric, so only the newest TVs and gaming consoles currently on the market support it. However, that will likely change over time as HDMI 2.1 slowly becomes the dominant version of HDMI.

In summary, if you're happy with the way your devices are performing today, then you're probably set; there's no need to rush out and get new HDMI cables, even with all the new versions of HDMI coming out. That said, if you run into a situation where you need a newer cable, go ahead and shell out a little extra money to make sure you've got the right cable for the job; it'll be worth it in the end.