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

Currently, the vast majority of televisions or Smart TVs on the market are 4K. Quite inexpensive models already include panels with this resolution due to how quickly they have become cheaper to manufacture. But, is the content we see in 4K really true or are they deceiving us?

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 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 the two.

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 business standard of the Digital Cinema Initiative and is popularly known as DCI 4K. A format in which the resolution is 4,096 x 2,160 pixels and the aspect ratio is 1.9: 1. In comparison, a UHD image has a resolution of 3,840 x 2,160 and an aspect ratio of 1.78: 1, which indicates that a panel that was truly 4K should be 256 pixels wider.

Almost all the content that is presented on television is done with a 1.78: 1 aspect ratio, 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.

Scaled with AI

Although we are in the era of 4K televisions and 8K has already begun 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, an analysis of the received signal must be done to determine the type of resolution, whether it is live TV or Full HD transmission. The next step would be to do with noise reduction: 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 quality of the 4K television, the rescaling will be of a higher or lower quality. So we will be viewing a “fake” 4K, since the content has had to go through an adaptation process 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 at the editing level so that the television already receives content in 4K. 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.

Classic 4K Movies

With the arrival of 4K there have been a large number of films that are several decades old, such as The Godfather from 1972, Jaws 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, films 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 reducing the amount of information in each frame.

Today with 4K resolution it is possible to capture much of the entire level of detail that the original film has depending on the type of negatives. Remastering is quite a complex process, but thanks to it we can watch classic movies in 4K 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 a 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 movie that have marked the history of cinema, to be able to scale it to 4K and 60 fps .