A/V Veteran

Last year the Consumer Electronics Association (CEA) laid down what it considered the minimum standards for a 4K Ultra HD set. A few months later it introduced a voluntary UHD logo program that manufacturers could use in advertising and labeling sets that meet the standards. This logo also clarified the name to be used for these sets: 4K Ultra HD. While manufacturers are free to make and sell 4K Ultra HD sets of any description (the CEA has no legal authority to stop them), they can’t use the logo if their sets don’t meet these standards. The logo will read either 4K Ultra HD or 4K Ultra HD Connected (though there’s nothing to stop a manufacturer who doesn’t meet the standards from calling their sets simply 4K, or Ultra HD).

The use of this logo is available from the CEA by license. A manufacturer can choose to not use it on sets that meet the standards, or ignore the standards and not use the logo. But the commercial pressure to meet the standards and use the logo will be hard to resist.

But meeting the CEA standards is hardly a challenge. They include:

1. Resolution – At least 8 million pixels, and a resolution of at least 3840 x 2160.
2. Aspect Ratio – 16:9 or wider
3. Upconversion – Can upconvert HD video (1080p or 720p) to Ultra HD resolution.
4. Digital Input – One or more HDMI inputs supporting at least 3840 x 2160 native content at 24p, 30p, and 60p frames per second. At least one of the 3840 x 2160 inputs shall support HDCP 2.2 (the copy protection scheme expected to be used on all commercial 4K material) or equivalent.
5. Colorimetry – Processes 2160p (4K) video inputs according to ITU-R BT.709 color space. May support wider colorimetry standards.
6. Bit Depth – Has a minimum color depth of eight bits.

In addition, to carry the logo with “Connected” appended, the set must meet all of the above plus the following:

7. Video Codec – Delivers IP-delivered video of 3840 x 2160 resolution using the HEVC compression codec (also known as H.265). May also include other standard codecs.
8. Audio Codec – Receives and reproduces, and/or outputs, multichannel audio.
9. IP and Networking – Receives IP-delivered Ultra HD video through a Wi-Fi, Ethernet, or other appropriate connection.
10. Application Services – Supports IP-delivered Ultra HD video through services or applications on the manufacturer’s chosen platform.

The concerns I have with these standards is that they are not complete. You can drive a truck through the omissions. To be more precise:

1. No issue here.
2. No issue here either, though this no different than 1080p standards.
3. Good as stands, though it must be emphasized that the upconversion to 4K does not result in true 4K resolution any more than upconverting 480i to 1080p produces a true high definition picture. This distinction will be self evident to most of our readers. But it remains a confusing issue for many people, who will wonder why they should invest in a 4K source, including an Ultra HD Blu-ray player, when their old software can be upconverted to “full” 4K resolution by the set! There are still folks who think DVD is HD (it is digital, after all)!
4. In other words, any such inputs must be HDMI 2.0 plus HDCP 2.2.
5. Only BT.709 (Rec.709)! Hopefully we may move beyond that with the 4K Ultra HD sources we might soon see, particularly on Ultra HD Blu-ray (wider color is less likely from Internet-sourced material due to bandwidth limitations). The spec does say that BT.709 is a minimum and the set may support wider color, but does not require it and doesn’t specify either of the likely alternatives—a variation on P3 (the Digital Cinema standard) or (less likely, at least for now) the even wider Rec.2020.
6. A minimum bit depth of 8 bits. (8 bits per color, R, G, and B. This is always understood to be the meaning when referring to color bit depth). Really? That’s no better than what we have now. We hope to see at least 10-bits per color on Ultra HD Blu-ray, though not any time soon on Internet 4K. Again, that’s a bandwidth issue.

I won’t go into the “Connected” issue here, as this remains something of terra incognita until we see how things shake out. For now the minimum standards in 7-10 should cover what we’re likely to see from Internet-provided 4K for the next couple of years. Interestingly, no one is talking about 4K over-the-air, and thus the need for sets with 4K receivers in sets, because broadcast 4K is exceedingly unlikely an time soon. Stations only recently transitioned to 1080p (by the standards of their glacial update schedules). 4K broadcasting, if 4K proves a smashing success, may come by 2030—if OTA broadcasting still exists by then.

I’ll note, however, that the HEVC specification, which turns up only in the 7-10 “Connected” section, belongs among the 1-6 standards. Without including it there, the 4K Ultra HD set need only have an HEVC codec for an IP source. There’s no mandate for the set to handle HEVC from an HDMI connection—the connection you’ll be using from your Ultra HD Blu-ray player.

Parsing the Fine Print
As you can see from my comments on 1-6 above, to carry the 4K Ultra HD logo a set need only do 4K, plus offer at least one appropriate input suitable for 4K material over HDMI (which means Ultra HD Blu-ray at least for now—but note my reservation on HEVC, above). A wider color gamut? Only vaguely addressed. A deeper color bit depth and specifically defined wider color gamut? Nothing specific. And what about 4:2:2 color subsampling, a step up on our current 4:2:0. Or high dynamic range (HDR, which we understand will require HDMI 2.0a). Not a peep. As far as the CEA specs are concerned, 4K Ultra HD means 4K resolution plus appropriate HDMI input capability. As always, it’s up to the buyer to beware of the fine print. And there is no fine print.

In my reviews I also try to determine what’s in that fine print, though not always successfully. Manufacturers don’t always have ready answers, which may lie solely in the mind of an engineer in Japan. Or Korea. Or China). Sometimes there’s a language barrier here as well, and sometimes the information gets filtered through the manufacturer’s sales department (here or overseas) until it’s so vague as to be meaningless. But we try.

Addressing the Future—or Not
What sort of answers do I want? Answers that reflect on the future proofing of a given 4K Ultra HD set, at least insofar as this can be determined (there’s no such thing as absolute future proofing in today’s fast-moving tech world). I want to know not only if that 4K Ultra HD set has those resolution, color gamut, color bit depth, and HDR features, but that those features make their way from input to screen without being somehow downconverted midstream to fit through internal circuitry that may have been left over from last years 1080p sets, then upconverted again just before the signal reaches the LCD or OLED panel. An informed, independent industry expert recently told me that back in the Jurassic days of component video (when even HDMI was barely a gleam in the eye of the industry), at least one manufacturer converted the component input to S-Video as soon as it entered the set because they didn’t yet have the internal circuitry to directly handle component!

Expect to see turf wars spring up between manufacturers as all of this this plays out. It’s already begun. Recently LG announced a budget 4K LCD line using an RGBW pixel arrangement; that is, a white pixel is added to each set of RGB subpixels (this technology should not be confused with the WRGB configuration LG uses for its OLED models; it’s entirely different). Samsung, LG’s arch Korean rival, recently announced that it would participate in the 4K Ultimate HD logo program, and in the next breath suggested that the LG sets would not meet the CEA color standard. LG, or course, countered. Let the games begin!