The Evolution of HDMI

Remember when DVI and Firewire were the cat's meow? It wasn't that long ago that the acronym HDMI was non-existent. Today, it's nearly ubiquitous (thanks to Hollywood's help).

The standard has come a long way since its inception in 2002. Five updates later, questions still abound with HDMI 1.4.

“There have been a lot of questions about the different versions of HDMI. One thing I want to emphasize is that HDMI is backward compatible from 1.0 through 1.4," says Jeff Park, technology evangelist for HDMI Licensing LLC.

"What that means is the basic foundation of the spec that was first introduced in 2002 is the same, and all the new specs introduced since then have been added on top of the original foundation.

"That means if you installed a 720p plasma in 2002 and the client calls you back to install a new Blu-ray player in 2010, those two devices will work together at the highest point possible. But since the TV is limited to 720p, that means all the devices in the connection will automatically default to 720p. You are not going to be able to magically upgrade the client’s 720p television to 1080p by connecting it to a new cable or new Blu-ray player, but you are not going to lose the 720p capability."

That same backwards-compatibility holds true with HDMI 1.4., says Park, pointing out the new features that include:

HDMI Ethernet Channel — "This is the biggest new feature," says Park. The feature is a parallel data channel. According to In-Stat, 24 percent of all devices and 80 percent of Blu-ray players now being connected devices that need to communicate directly with the Internet for downloading purposes. Park says Video on Demand (VOD) is driving the demand for broadband-connected devices such as Netflix, Vudu and others. The HDMI Ethernet Channel feature was required to meet that demand.

"As you add this connectivity, you need to simplify the usage," says Park. "Having more and more cables complicates things. So, it is all handled with a single HDMI cable. It’s completely parallel to A/V communications, so the new Ethernet channel does not take away from the quality of the audio and video while enabling high-speed, bi-directional communication at transfer rates as high as 100Mbps."

Audio Return Channel (ARC) — In a TV with a built-in tuner, in the past an installer would have to run a separate audio cable between the TV and the receiver in order to get surround sound processing in a home theater set up. It really hasn’t been a common problem in the past, but as more VOD services are offered — only accessible through the TV’s built-in tuner — it will be.

Other features in HDMI 1.4 include 3D support, 4k/2k support, more color spaces and new connectors.


Click for full-size image