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October 26, 2016

Infrequently Asked Questions: What's the actual difference between HD and UHD?

It's nearly TV sale season so it's only reasonable to pose the question so many shoppers will face while strolling through TV departments and online landing pages this holiday season: What on earth is the difference between HD and UHD? And is one really worth lots more money than the other? 

In search of an answer that doesn't come from a Best Buy sales associate, we spoke with John Berton, assistant professor of animation and visual effects at Drexel University's Westphal College of Media Arts & Design

What's the actual difference between HD and UHD? The fundamental difference.

Well, UHD simply has a lot more pixels; it's made up of more pieces. Higher resolution, we're all familiar with that, what you do with a camera that has more megapixels than the last one had. It's a sharper image with more detail. And that's what you're looking at in the difference between HD, which is 1920 x 2000 pixels in the horizontal direction, and UHD, 4,000 pixels in the same direction. 

So, it's twice the resolution. And that's really the big deal. And it's also based on the hardware, right? So, for example, there's been a lot of content that operates higher than 1920 by 1080 and a great deal of what we see broadcast over TV and streaming is only 720 in the horizontal direction, and everything else is interpolated in between. They're kind of computer-made-up pixels. They're meant to give you that bigger display with more detail, but at the same time, we don't really have more detail because the original picture never had it. The TV, it can't make it up; it just does the best job it can to display.

Why's the implementation of all this so incremental? Why not start out with UHD to begin with if the capability is there? Is it the cost of production?

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Technology needs to advance as well. The sensors need to be better to record that kind of detail and that's what we've seen going on in cameras all along. We start with digital cameras in the 1990s, and they're really cruddy compared to what we have now because we didn't have the sensors — we could make sensors that read 4,000 pixels, but it'd be the size of a suitcase. And so now they've gotten that down to the point where it's containable within that camera you can move around. That's sort of the holdup with the source material.

But because TV sets are larger than  a camera sensor, it's gone to a higher resolution sooner because they don't need to miniaturize. You follow me? It's OK if the TV is the size of a suitcase; it's not OK if your camera is. And so the cameras have come along after. And then there's the matter of if you have more pixels, you have more data. More data, less bandwidth. It's hard to move these pictures around — to store them, to move them. 

They keep adding features to these screens without really any content to back it up. 

It takes a long time to change over [from HD to UHD] because it changes everything. Going to HD was one of the biggest changes and look how long it took to do that. We had [standard definition] for five decades before we could ever get someone to agree on a new standard. UHDTV, the so-called 4K ... will pull together a standard relatively quickly. But at the same time, it hasn't really been adopted by anybody, so the TVs are 4,000 lines but they are kind of based on existing technology of existing standards of high definition, which is 1920 by 1080, or 1080p. But this is why you're seeing this wide range of TVs. While the TV manufacturers are waiting for content to catch up, they still want to be able to say 'We have the coolest, latest thing.' They keep adding features to these screens without really any content to back it up. 

For example, I was at my son's apartment last night. He has a 4K TV; I have one also. And he said, 'Well have you looked at any 4K material?' And I said 'I haven't really had a chance to find any.' And he goes to YouTube and starts dragging up these 4K videos people have shot using 4K cameras. And there we are, finally, for the first time looking at images made at 4,000 lines on a 4,000 TV set. Without all the interpolation and blowing up the other TVs have to do. Now we're looking at something. ... And what are we looking at? Slow-motion footage of people dropping ink into water tanks. Motion of waves breaking on the Maui shoreline. The same stuff we saw when we went to HD, when photography was first invented, when cavemen were drawing on rocks in caves — the breaking shoreline. [Laughs]

Has anyone established what's after UHD?

I haven't heard of anything about that, apart from one thing. My research at Drexel right now is surrounding high frame rate. So even UHD is still running at 60 frames per second at best. This is actually a problem. People have various opinions about high frame rate. But the fact of the matter is, without high frame rate, the big TV sets we have now would strobe and look terrible And that's why when you go to buy a TV, 'Oh that's 240 FPS, 240 hertz,' that's to cover up the fact that if you look at a sports game — even turning at 60 frames per second, it's going to strobe because you don't have the number of frames playing per second to keep it from starting on a big screen. So they do all this interpolation at 240 FPS in order to take 60 FPS and divide it up into averages of the frames they already have to create this fake motion blur to keep it from strobing. People don't realize that's going on with their TVs, but it is. That's another way we need to improve our image-making, which I'm particularly studying. And I think it can be done within existing frameworks.

In terms of what's after UHD, well, they're going to get bigger, right? Next will be 8,000 lines and so on. And that will progress the same way camera and iPhone technology and everything else progresses. But at some point, I'm assuming cameras will catch up. Because you'll want to actually take advantage of all the pixels they're pushing now. And I think that will happen but it will take some time. There will be a breakthrough when all of this comes together. There's no reason for doing all of this interpolation if we can't actually produce the stuff, and I think it's just demand. And in terms of consumer products, it's just demand. If people knew what they were missing or could really get — people are out there sucking up OLED TVs at $3,000, because it's the coolest thing and they just gotta have it. And that's what's always been driving these TV marketplaces and audio before that. The enthusiasts will pay anything to have the latest, greatest thing.

What is an OLED?

It's a new technology. It's simply Liquid Crystal Diode TVs with the backlight behind them, a simple idea that produces great results. If someone says they have an LED TV, what they're really talking about is an LCD TV with a backlight run by LED. But OLED TVs are using a carbon molecular structure, a so-called organic LED. That's why they're called OLEDs, because they're made out of organic materials such as carbon silicon, and those are used to allow the LEDs to express light through the pixels without a backlight. They emit light themselves rather than have a backlight glow through them. So an LCD TV is producing color and then LED is producing a projection of light from behind. 

OLED, these LEDs emit the light themselves so they don't have that problem, which means you can turn them off all the way and they'll be black. With an LED, when you turn the LEDs down to zero, the glow, the inherent glow of the liquid crystal diode, still presents you with some light emission so that makes it not blacker than black. But with OLED, you can turn it off and if it goes to zero and no light is emitted, you get really deep, rich black — all the way to black, black, black. Which we've never had in TV, because the broadcast standard never supported that. There's always been lore of 7 percent on TV because they were afraid to go to zero, for some reason. There's' always been a gray at the bottom of television images, so we've never had the same kind of dynamic range you get out of film, for example, because you never get all the way to the bottom. Now with OLED you can.

What's with the brands? Samsung is the supposed gold standard, but is there a significant difference between what they're doing and others are doing?

I would say no. Samsung has been particularly good at marketing their latest innovation. For example, SUHDTV is just a new set of Samsung-based features they're sticking on top of everything else. There really isn't any new tech there apart from the software used to drive the picture. That's a significant move forward, but their marketing group is very good at pushing it out as the next thing after UHD and it's simply not as big a step as OLEDTV, as far as native technology.

And it also doesn't move us in any direction in terms of the other two areas we want to move forward in, one being higher frame rates and the other being higher dynamic range. High dynamic range is when you can display — you can collect info that is actually more, that has more range than light can display. And this has been going on for 20 years now that we have cameras that can collect info about color and light they're seeing far beyond not only the ability of the displays to show them but also the ability of our eyes to perceive them. You're collecting data about the world that goes beyond what you can actually produce. But you still have the data. You have an HDR thing on your iPhone, and what it does is it takes a picture that is exposed when it's dark outside and takes one from light outside, and it takes a picture that's exposed correctly of the scene used in front of it, and then it does interpolation for those things — takes all the parts correctly exposed, and compresses them into a space you can't see. And that's what people talk about with HDR images. But what it really is, is an image which still contains all of that info. It hasn't been compressed ...

We have cameras that can collect info about color and light they're seeing far beyond not only the ability of the displays to show them, but also the ability of our eyes to perceive them. 
High dynamic range is another thing you'll hear. And that's the big breakthrough: being able to display these HDR images. Where there's a limitation [to] what the human eye can see, the limitation of what a monitor can project is much, much greater. It is nowhere near what we can see. Even though we can't see everything, the monitor is showing us a small amount of what we can see. So there's a lot of room to improve the monitors before we're at a position we can't see everything in front of us anymore. Which is what we have with reality: If it's too bright outside, we have to put sunglasses on or you can't see. Same thing. Someday we want to have monitors, picture-projecting devices that have that characteristic: If it's too bright, you put sunglasses on or you can't see everything.

Any general advice as people are out shopping in the next two months?

Look at the pictures in front of you and choose the one you think has the look you want. All these things can be adjusted. What you see on the showroom floor is just the way they have it set. But you can find what you're looking for in terms of the size of the image you want and the quality of the control that you have over it. Have the people on the showroom floor show you how to adjust things a bit and then you'll be able to see what's out there.

There's going to be a change in technology soon, and I think, it depends on how much you want the latest, greatest thing. I went out and bought a UHDTV a couple weeks ago but I didn't go to the HDR side of things yet because it's not mature yet. So I didn't buy the top-of-the-line thing. You can spend the money on the top-of-the-line stuff, and have a lot of great stuff and see things people can't see, and OLED TVs are terrific, and some HDR TVs are also very good, but then again you can buy a really great TV ... and then in a year or two there will be one that's tremendously better. So it's going to be the same game as smartphones and digital cameras, where the technology is going to be racing ahead. You're not going to buy a device that sits around for 20 years like your old RCA or Motorola did. And it's a hardware device — not upgradable. You can't install a new operating system and it's upgraded — it's manufactured. So make your investment based on the amount of time you'll be happy with the technology until the next thing comes out.

The big thing I would say about buying a TV today, is you have to change your mindset from how you would buy a car, and change it more to how you would buy a phone.