The establishment of standards for high dynamic range (HDR) viewing in the home and other 4K UHD performance issues needs to take into account a wide range of parameters including ambient light and its effect on contrast ratio, and not focus merely on peak light.
That was the assessment of some video experts speaking on a Next TV panel at CE Week in New York City Tuesday.
“Research has been released now that has established the dynamic range in peak light output at more than 1,000 Nits, and I am going to take issue with that research,” said Joe Kane (pictured above with mic), video technology consultant to Hollywood and a founder of the Imaging Science Foundation. “We did similar research with Eastman Kodak in the Seventies, and what we found is, yes, consumers want upwards of 1,000 Nits [of peak brightness], as has been proposed, and that’s true, but we also found that when you put somebody in a room to watch a two-hour movie, the ambient light has to be up there as well.”
Kane explained that if a picture is too bright in a dark room it becomes fatiguing to the eyes, and reflected light on the screen impacts on the contrast performance seen by viewers.
“Because contrast ratio goes down as ambient light goes up, I would like to propose that high dynamic range have to do with contrast ratio and not absolute light output,” Kane said. “We can go as high in light output as we want as long as the contrast ratio that we see specifies what is high dynamic range. If you are going to watch a set with 4,000 Nits, you are going to need an awful lot of light behind that set if you are going to watch it for two hours.”
Read more on the panel’s discussion for standards establishment for HDR, wide color gamut and other issues after the jump:
Mark Schubin, engineer-in-charge at the Metropolitan Opera and video tech consultant, first raised the issue of contrast and dynamic range on the panel when he listed a series of good news and bad news points about the introduction of new televisions supporting HDR.
Schubin defined dynamic range as “the range from the darkest to the lightest thing that you can perceive in a picture. It is essentially the same thing as contrast ratio. But different TVs have different brightness levels. If you were to take about 15 TVs today you’d find a range from about 138 to 1,000 Nits, so that’s about a 7:1 ratio there. They also range from .7 to 2.6 percent reflection, which is about a 4:1 range of reflection, so if there is a light on in the room that is going to affect your contrast range.”
Schubin said that some of the challenges ahead for HDR include: “How do we get the extra high dynamic range to the TV? There are different ways that people watch TV and there are easy ways of doing it in any of these systems, but we have to agree on what that is. Then you have a situation with some TVs today that have a maximum brightness of 138 Nits and some have 1,000 Nits. How do we deal with both of those? How do we know what viewing issues are? How do we know how many lights are on in the home? How much is being reflected off the screen?”
Schubin also raised the issue of the extra power consumption required to push brighter panels.
“With one Samsung TV for example, typical power consumption is listed at 110 watts and peak watts are 351 watts. That’s more than a 3 to 1 change between typical and peak. What happens when a commercial comes on and they decide to have a white field in the background? Do we now violate State of California law on power consumption?” Schubin asked.
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Bob Kisor, entertainment industry consultant, said that, “if we can reliably deliver HDR content to consumers it would be good to include file format specifications that would be interoperable across all manufacturers’ and determine a single set of universal metadata that would say what’s necessary to accurately display the content. And even if we have the universal set of metadata can that be reliably carried in the infrastructure? Will it survive a live broadcast stream and change of infrastructure? And is there a broadcast scenario in the next five years?”
“These are the questions that CE manufacturers, program writers and platform providers need to wrestle with in order to figure out how to get the consumer the content that we are promoting so aggressively,” Kisor said.
Nandhu Nandhakumar, LG advanced technology senior VP working with OLED displays, said that “for some reason, in the recent past, people have focused on image brightness as the only relevant parameter for image quality. I want to dispel that notion. I think that is a very dumbed down version to market to consumers. A package of increased capabilities for displays and production technique will really lead to compelling value propositions for the consumer viewing experience.
“Our eyes have the ability to view a very wide range,” he continued. “All the way from starlight on a dark night all the way up to bright sunlight almost looking at the sun. The challenge has been to create content that mimics that wide range of reality, and to create displays that create that wide range of values.”
Kane used most of his time on the panel advocating that standards be established for “a container” of digital information including a wide range of information extending to the highest available capture capabilities for color, dynamic range and other criteria, from which television sets can pull out the information they are capable of presenting in the best quality possible for that display.
“Of these newer technologies, they all have different capabilities. Each technology can bring its own capability to a new system,” Kane said. “The challenge becomes what do we do with all of those different technologies? Part of what we have seen in the UHD area is that a whole bunch of new proposals are possible. The Hollywood mantra is now: `More, Better, Faster.’ ”
“..This is Hollywood’s way, in my opinion, of never being behind again. So they will always be out in front of whatever happens to come by,” he continued. “So we now have a system in place whereby we can hang on to everything that we can capture. That means we have a whole bunch of things that might be put into UHD. The most important thing that I would like to have considered for UHD in the future is it no longer be behind any particular display device,” noting that for decades standards of television performance were based on cathode ray tube technology.
Kane said that in establishing the Ultra HD platform, “I would like UHD to be first the container and second the pipeline to how it will get the information to the consumer. We need to consider the ultimate goal. Otherwise the increments we are talking about today won’t get us to where we belong. In my world, I want to dream about the future system and know where we are going, with the attitude that when we take steps we are taking steps toward the ultimate goal.”
(Panelists pictured above, from left: Nandhu Nandhakumar, LG; Mark Schubin, SchubinCafe.com; Joe Kane and Bob Kisor, entertainment industry consultants.)
By Greg Tarr
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