4k video: what is it based on and what are its advantages and disadvantages?
What should we know about these formats?
When we talk about 4k or UHD (Ultra High Definition) we do it when referring to image sizes that have approximately 4000 pixels of horizontal resolution, since it really is not the same. It is simply a matter of marketing that is already very difficult to change. Let’s look at the differences between 4k and UHD.
The 4k used in the cinema is called DCI 4k, its characteristics are a bit different from that used in television. It has a resolution of 4096 x 2060 , this is because before the arrival of the 4k the cinema worked with a 2k format of 2048 × 1080 pixels so they doubled its resolution. Which implies an aspect ratio of 17: 9.
When we talk about UHD, we do it by referring to the so-called 4k for television, a resolution format smaller than the cinema, since it multiplies by two the Full HD standard of 1920 x 1080 which makes it a 3840 × 2160 resolution format. With an aspect ratio of 16: 9.
We must bear in mind that, if we use the 4k DCI format on our televisions, the videos should include two black stripes of 128 pixels each, to compensate for 256 pixels of difference.
When we talk about 4k we do these two formats, but it is good that we know, even if it is a little and without deepening much, that there are differences. This article is intended for 4k recording for video and television.
Advantages of recording a video in 4k
We already know that the 4k resolution is four times higher than Full HD or 1080p , the higher resolution and the better image sharpness. But if I’m going to export a video in Full HD, why record it in 4K? There are several advantages :
The possibility of making camera movements in postproduction.
By having a resolution 4 times higher, we have two options: reduce the image and adapt it to Full HD, or keep the size and choose the part that interests us and even make camera movements at the time of editing, this ensures us fluid movements and without loss of quality.
Low light conditions
We know that in unfavorable light conditions the use of the telephoto lens is very complicated, although we have high quality optics we will always have a higher f-number than when working on angles. Once we take this into account and know the advantage mentioned in the previous section, we will have a video in Full HD without the need for an optical zoom.
New compression codecs
At the moment we have a very powerful compression codec such as the H.265, it duplicates the compression of the H.264 and partially solves one of the biggest disadvantages of the 4k files, which is specified below.
Evolution of the market itself
Until a few years ago those who bought a camera for 4k video were not sure how the market would behave. But we can already see that all the big companies of television, video games, mobile phones and computers are betting on this technology.
Greater color depth
Even in 12-bit videos.