HDMI 1.4 Explained: What's New in the New Spec
By Adrienne Maxwell
The first crop of HDMI 1.4-equipped HDTVs and Blu-ray players have begun to hit retail shelves, with A/V receivers and other products soon to follow. Chances are, if you've heard talk about HDMI 1.4, it involves the spec's support of 3D playback, but that's just one of several new features--some of which could prove extremely useful in this era of Web-friendly A/V devices.
Here's a rundown of everything new in the HDMI 1.4 specification:
3D Support
HDMI 1.4 defines common 3D formats and resolutions for HDMI-enabled devices. Both HDMI 1.4 and HDMI 1.3 are capable of the same data rate of 10.2 Gbps (up to 340 MHz), so higher speed is not an element of the new spec's 3D support (a Full HD 3D signal has a data rate of 6.75 Gbps). HDMI 1.4 standardizes the input/output portion of the home 3D system, and the spec lists mandatory 3D formats that must be implemented in displays, sources, and repeaters to "facilitate interoperability among devices, allowing devices to speak a common 3D language when transmitting and receiving 3D content" (as HDMI Licensing, LLC describes it). We'll discuss this more in an upcoming series on 3D.
HDMI Ethernet Channel
Network connectivity and access to Web content are certainly the "It" features in the current generation of HDTVs, Blu-ray players, gaming consoles, and other CE products. That network connection currently comes in the form of either an Ethernet port or a wireless transmission system (via a built-in WiFi antenna or an add-on USB adapter). HDMI 1.4 offers a third option, adding a data channel that supports bidirectional communication to send and receive data at speeds up to 100Mbps. If you have several networkable products in your home entertainment system, you no longer have to add each device to your network individually; instead, HDMI 1.4 would allow you to feed your network connection to just one device and then share it with other network-enabled products over the same HDMI cable that you use to transmit the video and audio signal. It would also allow these devices to share content. Obviously, every device you'd like to network must support the Ethernet Channel function, and you'll need to use the proper HDMI cables (more on this in a moment).
Audio Return Channel
One of the lesser-hyped additions, the audio return channel could actually prove to be one of the spec's most useful functions. HDMI 1.4 supports the ability to send a digital audio signal "upstream" from your TV back to your A/V receiver. Many current HDTVs offer a digital audio output to send an audio signal from the TV to your home entertainment system; a common use is by those people who employ the television's internal tuners and wish to send the accompanying audio to an external sound system. As a growing number of TVs incorporate video-on-demand and other media-streaming applications, more people will likely wish to send audio back to their A/V receivers. With HDMI 1.4, it won't be necessary to run a separate digital audio cable to do so; instead, the audio return channel can handle the task, and it supports the same audio signals that can be sent through a traditional S/PDIF audio connection, such as Dolby Digital, DTS, and PCM audio. Once again, this function will require that both the TV and receiver have HDMI 1.4 with the Audio Return function enabled.
4K Support
Just when you thought that 1080p was the ultimate in high-def viewing, along comes 4K, which generally stands for 4096 x 2160 pixels--over four times the resolution of 1920 x 1080. Currently, 4K is utilized primarily in professional digital cinema systems, and only a few high-end consumer-oriented 4K projection systems exist. However, we will see more 4K products in the future, and HDMI 1.4 supports 4096 x 2160 at 24Hz, as well as 3840 x 2160 at 24Hz, 25Hz or 30Hz.
New Connectors
The previous HDMI 1.3 spec gave us the HDMI Mini Connector; the new spec gives us the HDMI Micro connector, designed for use with portable devices like cell phones, media players, and digital cameras. This tiny connector puts the same 19-pin design in a shell that's about 50 percent smaller than the HDMI Mini. It supports all of the HDMI 1.4 features. The new spec also includes an Automotive Connection System for in-vehicle HD content distribution. This system is designed to handle challenging issues like heat, noise, and vibration in the automotive environment.
More Color Spaces
If you plan to connect your digital camera directly to your HDTV via that new HDMI Micro connection, you'll be happy to know that HDMI 1.4 also supports several new color spaces that are specific to digital still cameras--namely, sYCC601, AdobeRGB, and AdobeYCC601. Support for these formats is designed to help ensure consistency and accuracy between the camera and the HDTV.
As you can see, HDMI 1.4 introduces some compelling new features. As is always the case when bringing out a new spec, though, the transition could be a little confusing. For one thing, just because these new features are in the spec does not guarantee that they will appear in every HDMI 1.4 device. A manufacturer can choose which features to include; for instance, many of the brand new HDMI 1.4 products do not include the Ethernet and Audio Return Channels. If a certain HDMI 1.4 feature interests you, make sure that it is actually implemented in the new equipment you purchase.
Products that employ the new HDMI 1.4 specification will be backwards compatible with all existing HDMI devices and their features, but you obviously won't be able to enjoy new 1.4 features like the Ethernet and Audio Return Channels unless you upgrade multiple components in your system to HDMI 1.4 products. In other words, just because you buy a new receiver that touts Audio Return doesn't mean that feature will work with your existing equipment. You would also need a TV that supports Audio Return. Such is the nature of our ever-evolving industry.
HDMI Licensing, LLC says that it is "not likely" that older HDMI devices could receive a firmware update to be 1.4-compliant, as the new features will require a new HDMI chip. One notable exception involves 3D playback. Sony has released a firmware update for the PlayStation 3 to enable 3D playback, which is possible because of the PS3's more PC-like graphics-card output, compared with the chip in a traditional Blu-ray player. Likewise, cable and satellite providers have announced plans to support 3D playback through existing set-top boxes, which may require a firmware update.
Finally, HDMI 1.4's enhanced functionality creates a need to enhance the current lineup and labeling of HDMI cables. The two existing cable categories, introduced with the arrival of HDMI 1.3, are still valid. The Standard HDMI Cable (also known as Category 1) supports 720p/1080i and has been tested to perform at speeds up to 2.25 Gbps. The High Speed HDMI Cable (or Category 2) supports 1080p or higher and has been tested to perform at speeds up to 10.2 Gbps. These cables support all of the new HDMI 1.4 features except the Ethernet Channel. (For 3D and 4K, you'll need the High Speed HDMI Cable.) If you purchase HDMI 1.4 devices that support the Ethernet Channel, you need to look for the new cable offerings: The Standard HDMI Cable with Ethernet and the High Speed HDMI Cable with Ethernet have the same specs as above but add Ethernet support up to 100 Mbps. Finally, there's the new Standard Automotive HDMI Cable. All new HDMI cable products will be required to carry one of the above labels.
