UHD and 4k - these are the differences

Everyone is talking about UHD and 4k TVs. We explain the exact differences in this practical tip and show which streaming provider already provides content for it.

UHD, 4k, 8k ... - the differences in the resolutions in the overview

Popularly and even in specialist articles, the terms UHD and 4k are often mixed up. In the publications of the Institute for Broadcasting Technology and the recommendations and standards of the International Telecommunication Union (ITU) you will find clear definitions and delimitations. You can roughly differentiate between SD, HD, UHD, 4k and 8k using the following guidelines:

1. Standard definition (SD) with 720 × 576 pixels is mostly used for DVDs. The aspect ratio is usually 16: 9.
2. High definition (HD) usually means full HD with a resolution of 1920 × 1080 pixels. HD is sometimes referred to as "2k". That is exactly five times as many pixels as with SD. The aspect ratio is also 16: 9.
3. Ultra HD (UHD) has a resolution of 3840 × 2160 pixels. That is exactly 4 times as much as HD and 20 times as much as SD. The aspect ratio is still 16: 9.
4. 4k is used by digital cinemas (DCI) and usually corresponds to a resolution of up to 4096 × 2160 pixels. This is an aspect ratio of slightly more than 17: 9 and is brought to the typical ratio of about 21: 9 by "cropping", ie the cutting away of pixels.
5. Colloquially, 4k refers to all resolutions in the order of 4000 horizontal pixels, i.e. both UHD and DCI resolutions.
6. HDTV was introduced together with the H.264 codec. Typical codecs for UHD and 4k videos are High Efficiency Video Codec (HEVC), like the H.265 codec.
7. 8k is the colloquial name for the Super Hi-Vision System (SHV) of the public TV channels in Japan (NHK) and is scheduled to go into regular operation there in 2020. SHV comprises 7680 × 4320 pixels, i.e. 80 times SD, still in a 16: 9 ratio. The same resolution is also intended for UHD2.
8. However, the trend is moving away from increasing resolution towards expanded color space, higher dynamics (contrast range) and higher frame rate in order to increase the image quality.
9. Find out which software you can use to edit and convert 4k videos in this CHIP online practical tip.

Since, despite standards and recommendations, terms are not used uniformly in the professional world or in colloquial language, you should make sure when buying whether a TV advertised as "4k" does not actually offer UHD resolution. At CHIP Online you can find out whether buying 4k / UHD TVs and monitors is worthwhile at the moment.

4k streaming: it's already here

The following websites already offer 4k quality streaming:

• Amazon Instant Video
• Netflix
• Vimeo (download also possible)
• YouTube
• Wuaki.tv

The best UHD and 4k TVs can be found in this CHIP test and the UHD best list of all top TVs. The first affordable 8k TVs are expected this year, as the 2020 Olympic Summer Games in Japan will be broadcast in 8k. You can find out more about 8k televisions in the next practical tip.