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Home / Tips and Tricks / What is 4K resolution? An overview of Ultra HD

What is 4K resolution? An overview of Ultra HD



The 4K Ultra HD logo.
ahmetemre / Shutterstock

If you̵

7;re buying a TV or upgrading to a next-gen console, you’ve likely seen terms like 4K and Ultra HD. Let’s cut the jargon and find out what these terms mean and if they are even interchangeable.

Everything revolves around dissolution

Typically, 4K and UHD refer to a resolution that has been improved from 1080p (or “Full HD”). A 4K UHD display is roughly four times the pixels of the previous generation, which results in a cleaner, more detailed picture.

An advertisement for 4K Ultra HD Blu-ray.
Sony

A 1080p HD TV cannot take full advantage of a 4K UHD picture. To see the benefits, you need to ensure that the media you are using is available in 4K UHD.

Fortunately, 4K UHD can be found everywhere from movies and TV shows to the latest video games. You can also buy a UHD 4K monitor for your computer for plenty of screen space and great picture quality. Your smartphone will likely record in 4K, even if the huge video files on a smaller display are not worth it.

4K and UHD are different

While 4K and Ultra HDR (UHD) are used interchangeably by manufacturers, retailers, and consumers, they are not the same. While 4K is a production standard as defined by the Digital Cinema Initiatives (DCI), UHD is just a display resolution. Movies are produced in DCI 4K while most TVs have a resolution equivalent to UHD.

The 4K production standard specifies a resolution of 4096 x 2160 pixels, twice as wide and long as the previous standard of 2048 x 1080 or 2K. As part of this production standard, 4K also specifies the type of compression to be used (JPEG2000), the maximum bit rate (up to 250 Mbit / s) and the color depth information (12 bit, 4: 4: 4).

A chart comparing the pixels offered by DCI 4K, 4K UHD, and DCI 2K resolutions.

Ultra HD has a screen resolution of 3840 x 2160 pixels and is used in most modern televisions – including those advertised as 4K capable. There are no additional specifications other than the number of screen pixels. The real differences between the two formats are the width of the images and the aspect ratios.

A movie produced in 4K can use an aspect ratio of up to 1.9: 1, although most filmmakers prefer 1.85: 1 or 2.39: 1. Video games that are rendered for consumer-grade displays use the UHD 1.78: 1 aspect ratio to fill the screen.

Because of this, the letterbox format (black bars at the top and bottom of the screen) will continue to appear when you watch movies on your brand new UHD TV. Since UHD does not specify any additional standards, older televisions with 8-bit panels are advertised as UHD devices alongside new 10-bit (and future 12-bit) UHD displays.

The areas 8K Ultra HD, 4K Ultra HD, Full HD and SD are compared.

To make matters worse, Ultra HD is also used for something called 8K content. Called “8K UHD” (as opposed to 4K UHD), this refers to content with a resolution of 7680 x 4320 pixels. This leap in quality is enormous in terms of the total number of pixels. However, it will take a while to produce widespread content for this format.

Simply put, many manufacturers use the term “2160p” to describe regular UHD content, although it is not precise enough when it comes to production standards.

Things to consider when upgrading to 4K

It’s a great time to upgrade to a UHD TV with 4K playback as the technology has matured significantly over the past five years. UHD displays are not only much cheaper now, they also offer more features. There are 10-bit panels that can display high dynamic range content and have powerful built-in image processors.

To make the jump worth it, you need to consider how big you want your display to be and how far from it you are sitting. RTINGS says it’s not worth the upgrade if you’re more than three feet from a 50-inch screen. You won’t be able to see the pixels from this distance anyway, so you won’t benefit from the increased resolution.

Another thing to consider is if you’re even watching enough 4K content to warrant the upgrade. Ultra HD Blu-rays offer the best viewing experience at home, and there is an extensive catalog that is constantly growing. However, if you don’t buy expensive discs often, you may no longer be stuck in streaming content.

This is where the speed of your internet connection can affect or affect your investment in a shiny new TV. Netflix claims that its customers need an internet speed of 25Mbps or better to stream Ultra HD.

You can test your internet speed to see how your display is doing. Keep in mind, however, that these speeds can drop significantly during peak hours (e.g. when everyone is streaming Netflix at the same time).

You’ll also have to pay for a premium streaming subscription to access the highest quality content. Netflix puts its UHD content behind a monthly package of $ 15.99. This might be worth it if you’re a fan of Netflix originals, most of which are streamed in UHD resolution.

Unfortunately, many films with UHD versions are still shown in HD on Netflix.

The subscription levels on the Netflix website.

Do you already have HD devices like a Roku or Apple TV? These can be a problem as they can only provide a 1080p image. You need a Chromecast Ultra or Apple TV 4K if you want higher resolution and HDR playback. This is less of a problem for your TV as long as it has a stable and responsive operating system, which many do.

Keep in mind that 4K lights up on larger displays. Unfortunately, when you upgrade to a larger native UHD TV, all of the 1080p content will look worse. However, this will be less of a problem in the future and there are some solutions.

Upscaling to Ultra HD

Current televisions place great emphasis on upscaling, which is the process of scaling lower resolution content to a much larger display. Remember that an Ultra HDR display has four times as many pixels as a regular Full HD television.

Fortunately, upscaling means more than just stretching an image. Modern televisions and playback devices process the image and try to reconstruct it so that it looks optimal at a higher resolution. This is done using a process known as interpolation, in which missing pixels are created on the fly. The aim is to achieve a smooth transition between contrasting image areas.

As televisions become more powerful, better interpolation and upscaling techniques are used. Right now, the NVIDIA Shield has some of the best upscaling solutions out there. It uses AI and machine learning to improve different parts of the image using different techniques.

If you’ve upgraded to an Ultra HD TV and experienced underperformance on lower resolution content, a shield might be for you.

The PlayStation 4 Pro uses innovative upscaling to render images at a lower resolution (like 1,440p), which are then upscaled to 4K using a technique called checkerboarding.

NVIDIA developed Deep Learning Super Sampling to do the same with PC games. Certain parts of the image are rendered at lower resolutions and then upscaled in real time. This will perform better than rendering the scene in its native resolution.

CONNECTED: What is “upscaling” on a TV and how does it work?

What about HDR?

High Dynamic Range (HDR) is also often advertised in movies and TVs, and it’s a completely different technology. While 4K is a production standard and UHD is a resolution, HDR is a loosely defined term that refers to wider color gamut and higher peak brightness.

While 1080p HDR may exist, HDR content wasn’t often produced in the age of “Full HD” so you won’t find TVs on the market that offer HDR at 1080p. However, the vast majority of 4K devices on the market support HDR in some form.

Don’t worry about the terminology

It doesn’t matter whether it’s 4K or UHD. Your UHD television is 4K capable. The world has just adjusted to the nebulous conditions of manufacturers and marketers.

Netflix may be promoting a movie in Ultra HD, while iTunes is labeling the same movie as 4K. Your TV doesn’t care and plays both of them just fine.

Before you venture out to buy this new device, however, be sure to check out these common mistakes people make when shopping for a television.

CONNECTED: 6 Mistakes People Make When Buying a TV




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