I’ve been collecting information on the rollout of UHD for several years, but haven’t had time to digest the rapid flow of data. With Black Friday rapidly approaching, I decided to focus on several issues that have caught my attention. One concern is that several UHD TVs I’ve been considering support 4:4:4 chroma sampling only at 30Hz.

Both 4:4:4 sampling and 60Hz operation are required to use a UHD television as a “desktop” monitor. To see the color graphics created by modern operating systems, the computer-monitor connection must support 4:4:4 chroma sampling. For smooth cursor movement, the connection must operate at 60Hz. Data-width, however, need be only 8-bits.

When a monitor will be used only to display video, such as an NLE’s Program window, some editors may accept a lower performance “client” monitor that supports 8-bit, 4:2:0 color sampling at 60p—or possibly even at 24/30p. (Although several new graphics boards can output 4K/UHD at 60Hz—it’s likely your computer’s current HDMI port can output UHD at only 24p or 30p. OS X 10.10.3 will, however, output 60p via a Single-Stream DisplayPort 1.2. Unfortunately, to date, no DP 1.2 to HDMI 2.0 Hz adaptor is available.)

Other than gamers, who want 4:4:4 at 120fps, there hasn’t been much interest in 60Hz beyond trying to anticipate Ultra HD Blu-ray support requirements. Obviously a 60p connection is required to support live sports programming, but most believed UHD 60p was not a practical broadcast format.

I was happily surprised when I read that from the end of 2014, Tata Sky was broadcasting live sports within India using 2160p50, 10-bit video. Follow this link to see a clip of a UHD cricket broadcast. The UK’s BT has already broadcast four Premiere League games in 4K, while Sky Europe will offer a UHD sports channel. DirecTV has launched a new satellite and is rolling-out a 2160p60 STB (C61K) for the USA. However, these 50p/60p announcements included a warning that not all UHD televisions would be compatible with these services. My first thought was the warning applied only to televisions with HDMI 1.4 ports.

Nevertheless, I decided to dig further and discovered that although HDMI 2.0 is correctly understood to support 60Hz—that isn’t the full story. There are two versions of HDMI 2.0: HDMI “Level B” and “Level A.” (See Figure 1.)

Level B supports 50p/60p, but at only 8-bits with 4:2:0 color sampling. Level A provides a significant performance increment. At 8-bits, 4:4:4 sampling is supported and with 12-bits, 4:2:2 sampling is available.

While HDMI performance specifications are confusing, they are nowhere as byzantine as High Dynamic Range (HDR) specifications. HDR is television’s version of toothpaste’s “New and Improved.”

We now know a good deal about Ultra HD Blu-ray. It employs a REC. 2020 color space, 10-bit H.265 compression with 4:2:0 color sampling, all at up to 60fps. However, when it comes to Ultra HD Blu-ray HDR, the mid-2015 specification reads; all discs will support the mandatory [open] HDR specification: SMPTE ST 2084. (2084 specifies an Electro-Optical Transfer Function—EOTF—and its inverse.) It is a product decision as to whether they will also support one or both of the optional HDR technologies: Dolby and Philips.

Of course, anxiety about these technical details comes down to “will the UHD TV I’ve bought, or am planning to buy, support Ultra HD Blu-ray HDR.” And, will it support HDR via streaming. The CEA recently published a definition of the minimum capabilities of an HDR “compatible” display:

• At least one interface that supports HDR signalling as defined in CEA-861-F as extended by CEA-861.3 (Level A HDMI 2.0a).
• Receives and processes static metadata compliant with CEA-861.3 for uncompressed video.
• Receives and processes HDR10 Media Profile (10-bit, 4:2:0 colour subsampling, ITU-R BT.2020) from IP or HDMI.
• Applies an appropriate Electro-Optical Transfer Function (EOTF), before rendering the image.

Before looking at what is not defined, let’s look more closely at what is. To support the additional bandwidth required for metadata, the faster Level A HDMI 2.0 must be present. Likewise, HDMI 2.0a must be available.

While the incoming data must conform to a REC.2020 color space, the display panel need not—and likely will not for several years. (See Figure 2.) The widest color space measurement I’ve seen matches the DCI-P3 specification. Quantum Dot or OLED technology is required to support Wide Color Range (WCR) images.

While the CEA specification defines what can be called an HDR compatible TV, it does not define HDR itself. Not defined are performance parameters such as minimum (black-level) and maximum brightness (practical maximum panel intensity). Thus, what’s not yet defined is the dynamic range that must be delivered by a High Dynamic Range television. The CEA is leaving this decision to industry groups such as the UHD Alliance.

I’m sure by CES 2016 all the parameters for UHD will have been defined and will be implemented in 2016 model year UHD televisions. Therefore, by Summer 2016 the multi-year rollout of UHD should be complete.

While I have always supported UHD, when I consider that the marketing of UHD2 (8K) will likely begin by CES 2017, I can only think of the movie A Bridge Too Far.