Which is better UHD or LED

Buying TV made easy: What is HDR, OLED, QLED, UHD & Co.?

Buying a television used to be so easy: depending on your budget, you chose the manufacturer and size. The analog TV picture - regardless of whether it was cable, satellite or antenna - looked great depending on the price range and the channels were hopefully distributed to sufficient storage space. Today, buying a TV is almost like choosing a computer. In addition to budget and size, depending on the manufacturer, you decide more or less for an operating system, display or lighting technology, more or less available online features and, and, and ...

In this article, we will briefly explain the most important technical terms that you may stumble upon when buying a TV. Don't let an X for a U fool you in the electronics market. With us you will find out what your new TV can do, what numbers mean for certain features and more. Our TV glossary is sorted alphabetically where possible. We have combined related terms such as 4K and Ultra HD. The article will receive updates in the future to help you buy a TV.

4K / Ultra HD

In TV advertising, Ultra HD, UHD and 4K now describe the same thing. Actually, however, 4K (also 2K) comes from cinema production and usually has a resolution of 4,096 x 2,160 (2K: 2,048 x 1,080) pixels. However, the industry issued standards for which the names Full-HD (1,920 x 1,080) and Ultra-HD / UHD (3,860 x 2,160) established themselves on the TV market. These are the common resolution figures for conventional TV sets today. In the professional area you will find screens or all-in-one devices that can offer 5K, for example, such as the Apple iMac 2019. In the games area you will also find medium sizes and other formats. They then call themselves WQHD (2,560 x 1,440), UWQHD (3,440 x 1440) and more. The four in 4K stands for four times the amount of pixels compared to the previous standard (comparison: 8 vs. 2 megapixels).

ALLM (Auto Low Latency Mode)

The "Auto Low Latency" mode describes a TV feature that recognizes consoles or PCs as an active input source. Similar to a frequently encountered gaming mode, the best settings are automatically selected so that the input lag (see below) is as low as possible. With ALLM, however, the result is better thanks to mandatory support from the player (e.g. Xbox One X): the input lag is significantly lower.

ARC / eARC - (enhanced) audio return channel

The audio return channel is an additional feature of the HDMI interface and ensures better communication between the television and the connected audio hardware. For a soundbar or an AV receiver, you no longer need a digital cable to get the best possible sound. In addition to ARC, you will read eARC more often in the future. This stands for Enhanced Audio Return Channel and is part of the specifications for HDMI 2.1. eARC offers more bandwidth, for example to transmit new formats such as Dolby Atmos via the existing, connected HDMI cable.

Operating system / OS (Operating System)

Like a computer, smartphone or tablet, a TV does not run without an operating system. In tube times this was kept very simple. It is now important to bring various apps, the program guide, the stations and much more under one roof in a clear and easy-to-use manner. LG relies on its own system web OS, Philips, Sony and more on Android TV, among other things. In some cases, older systems such as Tizen (Samsung) are also used, which are still being developed today. Find out in advance whether the selected TV set covers everything you might need in terms of software: apps for Netflix, streaming via built-in Chromecast, media player for USB storage and more.

Refresh rate / native hertz number, interframe calculation and frame rate / VRR

The refresh rate (also known as the vertical frequency) indicates how often (in units of Hertz) a display can change the image shown. The decisive value is the native Hertz number.

  • Excursus: In addition to the vertical frequency, there is also the horizontal frequency (or line frequency). This means in the unit kilohertz how many (thousand) lines per second a display can change.

Do not be dazzled by information such as 800 or even 1,000 Hertz and higher. This is a theoretical value that can be extrapolated using methods for intermediate image calculation. Manufacturers give this intermediate image calculation their own names such as TruMotion (LG), Motionflow (Sony) or Auto Motion Plus (Samsung). One or more intermediate image (s) are continuously extrapolated between two actually existing images, which are intended to give the appearance of a more fluid moving image display.

Motion smoothing is not particularly popular in the film industry. A “more than fluid look” is often associated with classic TV soap operas. In terms of visual aesthetics, these again belong a few steps below typical blockbuster productions.

The refresh rate should not be confused with the frame rate, which is more likely to be used in games and describes how many images per second a system can display in a game. In the future, you will also stumble across the term VRR - Variable Refresh Rate. The actually constant refresh rate is continuously adjusted 1: 1 depending on the frame rate. This ensures calmer and sharper images and thus more relaxed eyes with continuous use.

CI + / Common Interface

"CI +" slots can be found on most modern televisions, they are compatible with the PCMCIA slots that were once often found in notebooks. With TVs, you can place smart cards there (you may need a separate "CI +" module, an adapter, so to speak), which you need to receive, for example, pay-TV channels.

CI + allows, for example, the smart card of the (pay) TV provider to be operated directly on the television and thus to use the TV's tuner instead of its own separate box. When purchasing “CI +” modules, make sure that the TV is compatible with your provider's smart card.

Direct-LED / Local Dimming / Edge-LED / LCD

LCD technology has worked the same way for decades: liquid crystals that can change their color are backlit. While the first flat screens rely on a cold light cathode in the back of the display, today's LED screens (which are also just LCDs that are illuminated differently) use the eponymous “light-emitted diodes” as a luminous element. Edge LED describes LEDs that are located on the edge of the display. Direct LED displays have evenly distributed LEDs. Since these can be switched on and off locally, direct LEDs are also referred to as local dimming. This in turn stands for higher-contrast images and minimizes unsightly brightly lit areas in predominantly dark images. In comparison to LCD technology, OLED is really an innovation, more on that later.

Dolby Digital / DTS

TV or streaming signals do not only consist of picture information. The sound is part of it, of course. The TV sound usually comes in stereo, movies in multi-channel sound (mostly in the Dolby Digital standard). In addition to Dolby Digital, streams or content from DVD or Blu-ray can also be available in DTS, in their respective HD and 3D versions. If a corresponding TV supports one of the audio formats, no additional decoders or conversion are required. This could be done by another device in the form of a Blu-ray player or a service provider with its streaming app.

Dual / triple / multituner

It is possible that many TV sets are only fed by the router: Netflix, Amazon and Co. offer tons of entertainment at the push of a button. If you watch classic TV, you need a receiving device. This is usually the TV itself, which has to bring a tuner for it. As a rule, you only need cable (DVB-C), only satellite (DVB-S and the successor -S2) or only or as a supplement to the previous two DVB-T2 HD for your home. If a receiver is active in the TV, the EPG usually also works (without the Internet).


The Electronic Program Guide is comparable to a digital program guide. This is filled with content by the broadcasters, which you can access via the EPG menu on your TV. No internet connection is required for EPG, the exception of course are IPTV providers.

HDMI (and also: Toslink, Composite, LAN, ...)

The connections (type and number) of the TV are important: After all, you want to know whether there are enough cable slots for the game console, Blu-ray player, Fire TV or Chromecast. HDMI (High-Definition Multimedia Interface) is the standard for image and sound transmission in the living room and home theater. Toslink is less common thanks to ARC, but it is interesting for owners of older AV receivers or soundbars, because otherwise they have no way of transmitting the sound digitally.

Composite is the classic analog video plug, with one cinch cable for the picture and two cinch cables for the sound. Combined with an adapter, you could feed Scart connections with composite cables. Like composite, Scart hardly plays a role anymore. LAN connections are less common in the age of WLAN-ac and Mesh-WLAN, but just like with PCs, they are simply used for network connection.

HDR, HDR10 +, HLG, Dolby Vision and Nits / Candela

The usual 8-bit image (SDR, Standard Dynamic Range) describes 256 variants of each of the primary colors red, green and blue. This results in a total of 16.7 million colors that a conventional TV set can display. The general term HDR stands for High Dynamic Range and increases the possible number of colors to 10 bits. Manufacturers (not only of TVs) have different standards and more or less significant differences in the technical data. HDR10 +, for example, comes from Samsung, Dolby Vision from Dolby Labs and HLG is a community standard used by TV broadcasters.

At the moment there is no telling which standard will prevail. Netflix relies on Dolby Vision, Amazon on HDR10 +. TV stations want to use HLG for HDR images in the future. But the local TV landscape would first have to establish 1080p as the standard in order to continue watching. Along with HDR, you can also read about brightness information in nits or candelas per square meter. The higher the values, the greater the brightness of the TV for particularly bright or high-contrast images.

Extreme technology: HDR

The test boss and deputy editor-in-chief of video, Roland Seibt, explains what HDR and Dolby Vision are all about.

Input lag

Input lag is interesting for gamers and describes the period in milliseconds from the input to the visible execution on the TV. The value is best as low as possible. With ALLM, normal values ​​of around 20 to 30 ms can be halved again.


OLED stands for organic light emitting diode. These are self-illuminating diodes. A dedicated backlight is no longer necessary. This ensures, among other things, thinner displays and higher-contrast images, since black (in TV parlance, black means "light off") can be displayed more naturally than before. OLED TVs are ideal for evening home cinema use in dark surroundings, while QLED (see below) can offer advantages during the day in brightly lit rooms. OLED screens come from LG Display and can be found in televisions from LG, Philips, Sony, Grundig and more.

QLED (Quantum Dots)

QLED is a Samsung brand name. QLED displays are a further developed LCD / LED technology. The luminous crystals (quantum dots) are particularly color-intensive and allow, among other things, contrasts that come close to OLED technology. QLED televisions can combine better contrasts than LED TVs with greater brightness than OLED TVs. You should test for yourself whether OLED or QLED is better for you in a local electronics store.

Smart TV

Smart TV simply means the internet and media player capabilities of a device. These are largely dependent on the operating system. In addition to online surfing and streaming (online or from USB data carriers), it also includes skills for voice control or the like.

VESA standard

If you want to hang your TV on the wall, you need holes in accordance with the VESA standard. Matching numbers such as VESA 100, VESA 400 and others indicate in millimeters how far the drill holes must be from one another - on the TV and on the wall bracket.