HDR against 4k: What is the difference?

18 Сен

HDR against 4k: What is the difference?

When choosing and buying a TV, with a resolution of 4K or HDR, meditation appear, what format or permission to choose. Let’s look at the hype and find out that they actually mean at all.

4k refers to the resolution, which is indicated in pixels. For TVs, the 4K standard is 3840 x 2160 pixels. This means that the 4K TV displays 3840 (which is approximately 4k) horizontal and 2160 vertical pixels with the aspect ratio of 1.78: 1 (more often referred to as 16 × 9). The total number of pixels is 8,294,400 (approximately 8 megapixels).

4K permission 4 times exceeds the number of pixels (or twice the string) than 1080p. Four images of 1080p can fit in the space of one image with a 4K resolution.

4K (or any other declared TV resolution) remains constant regardless of screen size. However, the number of pixels per inch varies depending on the size of the screen. This means that as the sizes of the screen of the TV, the pixels increase in size and / or are located on apart to maintain the same resolution.

What you need to know when buying a TV 4K

Despite the fact that 4K TVs are displayed four times more pixels than 1080p, this difference may not be perceived on screens of less than 55 inches.

In addition to TVs, 4K is used in many home theater receivers, media stripes, Ultra HD Blu-Ray-players and Blu-ray players, which use 4K-apskings. It is also available in some video projectors.

Despite the fact that 4K TVs can improve image quality with lower resolution, to achieve the best results, you must connect components compatible with 4K, in combination with physical or streaming content, manufactured and supplied in 4K.

4K has not yet been introduced into the essential television broadcasting in the United States outside the field testing.

Consider the features of processing the movement of the TV.

Most 4K TVs are smart TVs.

4K TVs are available with HDR or without it (see below).


HDR means a «big dynamic range», which differs from permission. In the video, the dynamic range is a «distance» (contrast) between white and black in the image. In most cases, this distance is rather narrow and called SDR (standard dynamic range).

HDR is an increase in distance (contrast) between white and black, in which bright white snapshots can be fixed and / or adjusted so that they are more intense, but did not suppress the rest of the image, which would usually be due to overexposition. Dark areas can also be made deeper if the image does not suffer from undersensity.

When images with a high dynamic range are removed, the information is used in post-production for «sorting» content in such a way as to obtain the highest possible range from white to black.

Images are also sorted to obtain a more rich and accurate color, more smooth lighting and color shades, as well as to detect more parts in all parts of the image, including dark areas that are usually not visible.

Evaluation can be applied to each frame or scene or as static reference points for the entire film or program. After completing the HDR encoding, the content can be placed in the storage and / or delivery format (physical, streaming or broadcast) and viewed on a compatible TV.

How the HDR should look on the screen of your TV

When a TV with HDR support detects encoded content, bright white colors should be displayed without blur or blur, deep black should be displayed without turbidity or crushing, as well as hidden parts.

For example, in the sunset scene, you must see the bright light of the sun and the darker sections of the image with the same definition, as well as all levels of brightness between them.

There are two HDR display methods on TV:

Content encoded in HDR: The main used HDR formats are HDR10 / 10 +, Dolby Vision, HLG and Technicolor HDR. Content can be encoded in one or more formats. The brand / model of the TV with support for HDR determines which format it is compatible. If the TV cannot determine the compatible HDR format, it will display images without HDR.

Processing SDR in HDR: just as TVs improve the video signal with a lower resolution to comply with the TV screen resolution, the HDR TV with SDR scaling to HDR can analyze information about the contrast and the SDR signal brightness and expand the contrast range. So approaching the quality of HDR.

Not all TVs with HDR are created equal

As far as the HDR TV with support can display HDR depends on how much light can pay off TV. This is called peak brightness and is measured in threads.

For example, the content encoded in Dolby Vision HDR format can provide a range of 4000 yarns between the inhibitory and the most white. Few HDR-TVs can radiate as much light, but the increasing number will display up to 1000 yarns. Most HDR TVs will display less. The maximum value of HDR OLED TVs is 750-800, and many LED / LCD HDR low-frequency TVs can reach 500 Nits. However, OLED TVs can display absolutely black, and LED / LCD TVs cannot.

When the TV detects the HDR signal, but cannot emit enough light to display its full range, it uses Tone Mapping to best coordinate the dynamic content range of HDR with its own light output capabilities on the TV.

What you need to know when buying a HDR TV

HDR means the extended range of brightness and contrast displayed on the TV screen.

HDR does not depend on permission. This means that the use of HDR does not change the basic video resolution. HDR is implemented over 4k, not instead of it.

Due to its impact on brightness and contrast, HDR also improves color.

The visual difference between SDR and HDR is visible on any screen size. However, the HDR effect may differ from the TV to the TV due to differences in the ability of the light output.

Not all HDR TVs have SDR-HDR processing.

When buying a TV with HDR, pay attention to TVs that are compatible with HDR10 / 10 +, Dolby Vision and HLG formats, as well as with the possibility of maximum brightness of the TV.

4K against HDR — outcome

When buying a standard 4K TV or 4K TV with HDR, keep in mind the following.

Pixels are the basis on which 4K resolution is installed, and HDR is one of the ways to make pixels look better.

HDR has a greater visual impact than 4K.

Since 4K TVs are most of the televisions, available and sold, creators and distributors of content, as well as TV manufacturers preferred the use of HDR for TVs 4K Ultra HD over TVs 1080p or 720p.

In the US, all HDR TVs are 4K TVs, but not all 4K TVs are HDR-TVs.

To get the best viewing results, consider the TV with 4K and HDR support.