What you see in 4K, is it really 4K or are we being fooled?

The cheapest models of televisions with 4K panels can be around 400 euros on the market. A price that is quite affordable and for which many users have been encouraged to get hold of 4K resolution televisions. In addition, today streaming platforms such as Disney +, as well as the television services of operators such as Orange or Movistar offer content and channels in 4K.

UHD as synonymous with 4K

It can be said that 4K has become a buzzword. The trend of these panels on televisions, tablets, laptops or smartphones has marked a before and after. When devices with 4K panels began to be sold, most manufacturers used and still use the acronym UHD (Ultra High Definition) as a synonym for 4K. The truth is that there are subtle but important differences Between both.

Experts will tell you that most of the resolutions and quality of these televisions and content are lower than what the 4K resolution specification actually sets. The 4K format is defined by the agency’s commercial standard Digital Cinema Initiative and it is popularly known as DCI 4K. A format in which the resolution is 4,096 x 2,160 pixels and 1.9: 1 aspect ratio. In comparison, an image in UHD has a resolution of 3,840 x 2,160 and an aspect ratio of 1.78: 1, which indicates that a panel that is truly 4K should be 256 pixels wider.

Almost all content that is presented on television is presented with a aspect ratio 1.78: 1 which would force to show some black bands on the right and left of the image so as not to lose the aspect ratio when playing real 4K content. That is why the native resolution for devices that reach the end user is 3,840 x 2,160.

Resolution table

Scaled with AI

Although we are in the era of 4K televisions and 8K has already started to be talked about, not all the content we see is in 4K resolution. Also, Full HD images on a 4K panel look not better, but bigger thanks to the help of smart scaling. Adapting an HD image to a 4K display involves several steps. First of all, you have to do a signal analysis received to determine the type of resolution, whether it is Live TV or Full HD broadcast. The next step would be to reduce noise: textures and details are analyzed and refined accordingly. Lastly, the signal is converted to 4K matching the native resolution of the panel. Depending on the TV quality 4K rescaling will be of higher or lower quality. So we will be viewing a “false” 4K, since the content has had to go through a process of adaptation to be viewed in 4K.

So that the television or the panel does not have to do the rescaling, what they do with many contents is rescale them to edit level so that 4K content already reaches television. In this way, the television will not have to do additional work to resize said content because the image that will reach it will be in 4K regardless of whether or not that content was recorded in 4K.

Resolution comparison

Classic 4K Movies

With the arrival of 4K, there have been a large number of films of various decades old such as The Godfather from 1972, Tiburon from 1975, ET from 1982 or the classic documentary produced by the Lumière brothers “L’arrivée d’un train à La Ciotat” from 1896 looking like new with 4K resolution. But how is it possible if the contents were recorded in a time when 4K did not exist?

Until not many years ago, movies were recorded using 35mm negatives an old format, we are talking about 1892, which has a resolution of 4096 × 3112. A resolution much higher than what could be reproduced on a VHS, DVD or Blue-ray. When these films were first transferred to VHS and over the years to DVD, the quality of the original films was drastically reduced by decreasing the amount of information in each frame.

Today with 4K resolution it is possible to capture much of all the Level of detail that the original film has depending on the type of negatives. The remastering It is quite a complex process, but thanks to it we can watch classic 4K movies and enjoy details that only people who had the opportunity to see them projected could see.

For example, last year the Russian programmer Denis Shiryaev, through the application of neural networks, gave new life to the documentary produced by the Lumierè brothers “L’arrivée d’un train à La Ciotat”. This programmer was in charge of creating an algorithm to be able to scale the 50 seconds of a film that have marked the history of cinema, in order to scale it to 4K and 60fps.

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