What is High Definition and where it works ?hi

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Not all that long ago, terms like 4K and Ultra HD seemed like cues to faraway technology fit only for first adopters with thick wallets. Flash forward a few years and Ultra HD has become the new standard. If you’re looking to buy a new TV, nearly every model 40 inches or larger these days features Ultra HD resolution. But what if you’re not sure you need a new TV? Is the higher resolution noticeably better? Is an even better technology on the horizon? We’re here to answer all those questions and more.

Not all that long ago, terms like 4K and Ultra HD seemed like cues to faraway technology fit only for first adopters with thick wallets. Flash forward a few years and Ultra HD has become the new standard. If you’re looking to buy a new TV, nearly every model 40 inches or larger these days features Ultra HD resolution. But what if you’re not sure you need a new TV? Is the higher resolution noticeably better? Is an even better technology on the horizon? We’re here to answer all those questions and more.

At the consumer level, no. The two terms are practically interchangeable. But talk to professionals in the video production or cinema industry and they’ll chew your ear off about how what we lowly consumers call 4K isn’t actually 4K at all. Technically, they’re right.

In the professional world, 4K is a digital cinema standard that calls for a 4096 x 2160 pixel resolution. That first number is a horizontal measurement, the latter vertical, and they work out because they fit a 1.85:1 aspect ratio. Looking at those numbers, it makes sense to use the term 4K, because the horizontal measurement is in the four thousand neighborhood and is double the prior 2K (2048 x  1080) standard.

Still with us? Good, because now we’re going to come back to consumer television land, where the vast majority of us live. Here, we watch televisions with a 16:9 or 1.78:1 aspect ratio. That’s not quite as wide as what the pros use, and the pixel resolution we get ends up being 3840 x 2160

This is double both the horizontal and vertical measurements of the 1920 x 1080 standard (1080p, AKA Full HD) that most of us use today. Do that math and that’s four times the pixel resolution. That’s why you’ll hear TV makers talking about how 4K Ultra HD is four times the resolution of Full HD (1080p).

In 2013, the Consumer Electronics Association (CEA) — now referred to as the Consumer Technology Association (CTA) — decided that, to end confusion and make marketing easier, Ultra HD should be the official name for the new resolution standard. Unfortunately, people have been calling it 4K for so long the name didn’t really stick. Some manufacturers, like Sony, insist on calling it 4K anyway, so for our purposes, consider them essentially synonymous.

One might as well ask: Do I need a Porterhouse steak? No, of course not! You can do just fine with a sirloin, can’t you? Likewise, your 1080p HDTV will still work years from now because 1080p digital broadcast standards aren’t going to disappear the way analog broadcasts did back in 2009. Still, you might be tempted to upgrade once you sit in front of a 4K Ultra HD set.

Basically, if you’re happy with your TV, there is no need to change what’s already working. On the other hand, if you’re shopping for a new TV, it’s time to take the leap to Ultra HD.

The most immediately noticeable advantage is the higher pixel count. Ultra HD crams 8 million pixels into the same space in which a 1080p TV fits just 2 million pixels. It’s a noticeable upgrade, especially when watching native 4K content because the pixels are four times smaller and each one is getting a specific slice of the bigger picture. That, in part, is why Ultra HD makes more sense in larger screen sizes – the extra pixels have a bigger impact on a huge display.

Having more pixels on the screen doesn’t just mean a better picture on larger TVs, though. It also makes it more difficult to see individual pixels when you sit really close to any TV. So, snuggle up. It’s okay. While you’re there, you can take note of the fact that Ultra HD also offers a wider color gamut (adding literally millions of shades of extra color), greater bit depth, and with the majority of new TV sets, HDR. That last term is a whole rabbit hole unto itself, and we’ll talk more about it below. But let’s get back to Ultra HD.

Some experts debate the effectiveness of this higher resolution in screen sizes under 55-inches, and from typical viewing distances. We tend to agree that an Ultra HD screen has less of a payoff in smaller screen sizes for most people, but we’ve sat a 1080p TV down next to an Ultra HD TV for comparison, with the former playing a 1080p Blu-ray, and the latter playing an Ultra HD version of the same movie, and we’re here to tell you: The difference is visible at typical viewing distances.

While Ultra HD TVs were only available from some manufacturers a few years ago, that is no longer the case. You’ll still find 1080p TVs on sale — especially budget TVs — but as mentioned above, the vast majority of TVs that are average size or above are Ultra HD models. Of course, that doesn’t mean that every Ultra HD TV looks great, and you’re still better off sticking to models from bigger brands like Sony, LG, or Samsung.

Yes, it can, but to take full advantage of some of Ultra HD’s capabilities, your HDMI connections must be the right version. The HDMI standard that many older appliances use is HDMI 1.4, and that standard can handle Ultra HD resolution content at up to 30 frames per second. But, in order to better take advantage of Ultra HD’s higher frame rate, color, and bit depth capabilities, HDMI 2.0 is necessary. Eventually, all HDMI 2.0 inputs and above (including the current standard HDMI 2.0b version) will require HDCP 2.2 (high definition copy protection) compliance as well.

With new HDMI versions coming out, it’s fair to ask whether you might need new HDMI cables. With the older HDMI 1.4 standard, the answer was no. But now that HDMI 2.0b shoves so much more information down the pipeline, it actually might be necessary to upgrade your cables.

If you bought high-speed HDMI cables within the past couple of years, you’re probably going to be OK, but if you bought your HDMI cables several years ago, there’s a fair chance you will need to buy new cables. We have experienced signal dropouts and full-on cable failure in our own testing labs with cables we purchased just four years ago.

High Dynamic Range — commonly referred to as HDR — in TVs refers to multiple formats that provide brighter whites and darker blacks, making for increased color volume and shading and better contrast than standard displays. Many people (including us) say that HDR is a more noticeable upgrade than 4K resolution, and if you’re looking for a new reason to buy a TV, this is a great one.

Not all Ultra HD TVs support HDR, just like 4K itself, it’s becoming more and more common. There are also a few different varieties of HDR, including HDR10 (and its latest iteration, HDR10+) and Dolby Vision, the two most commonly used right now, as well as Hybrid Log Gamma, which is a broadcast-focused take that is starting to gain popularity.

Not all TVs support every type of HDR, and not all HDR employment is of the same quality. The technology is still moving forward, so you’ll need to be aware of what you’re buying. Fortunately, we have an entire guide detailing HDR, which can help you shop for what you need to get the best picture quality possible for your money.

Yes, but like HDR and other features, not all TVs are created equal in this regard.

In order for an Ultra HD TV to display SD (standard definition) or HD (high definition) content, that content must first be upscaled. Ultra HD sets need to convert SD or HD content to Ultra HD resolution before it can be displayed – it’s gotta fill all those extra pixels with something, right?

Take note, however, that while most of the big-name manufacturers’ Ultra HD TVs do a solid job with upscaling, some budget brands do not. This is far less of an issue than it was a few years ago when this article was originally published, but it’s worth pointing out.

The United States is giving high definition TV a big push by switching broadcasting standards from the use of analog and digital signals to exclusively digital signals. Although high definition TV (HDTV) can be broadcast through both types of signals, the quality seems to be better with digital, which is generally how the images are broadcast.

Ultra HD 4K content is less scarce than it used to be, but the sheer amount of HD content out there makes a TV’s upscaling prowess a crucial consideration. If the TV does a bad job of upscaling, lower definition content will look significantly less impressive than on a 1080p TV that processes HD content natively and well.