Comparison Kivi 50U740NB 50 " vs Kivi 50U740LB 50 "

The maximum brightness of the image provided by the TV screen.

The image on the screen should be bright enough so that you do not have to strain your eyes unnecessarily to view it. However, too high brightness is undesirable — it will also lead to fatigue. The optimal brightness level depends on the surrounding conditions: the more intense the ambient light, the brighter the TV screen should be. So, on a sunny day, the screen may have to be “turned up” to the maximum, and in the evening, in dimmed light, a relatively dim image will be more comfortable. In addition note that large screens require higher brightness, since they are designed for a greater distance from the viewer.

Thus, the higher the number in this paragraph, the greater the margin of brightness this model has, the better it will show itself in intense ambient light. The lowest indicator sufficient for more or less comfortable viewing in any conditions is 300 cd/m² for models with a diagonal of up to 32", 400 cd/m² for models in the range of 32 – 55" and 600 cd/m² for large screens of 60" and more. In this case, the brightness margin anyway will not be superfluous. But with lower indicators, you may have to darken the room somewhat for comfortable viewing.

The level of dynamic contrast provided by the TV screen.

Contrast in a general sense is the ratio in brightness between the brightest whites and the darkest blacks that the screen can produce. Other things being equal, the higher the screen contrast, the better the quality of colour reproduction and detail, the lower the likelihood that it will be impossible to see details in too bright or too dark areas of the image. Formally, the main characteristic of screens is static contrast (see above), but even in advanced matrices it is relatively low. Therefore, manufacturers went to the trick, introducing such a characteristic as "dynamic contrast".

Dynamic contrast ratio is the difference between the brightest whites at the highest screen brightness settings and the darkest blacks at the lowest. These contrast ratios can be quite impressive—much higher than static—however, it is impossible to achieve such values within a single frame, and dynamic contrast ratio is stated more for promotional purposes than for describing the actual specifications of the screen. However, it cannot be said that this indicator is completely unrelated to reality. The fact is that many TVs use automatic brightness control, which changes the settings depending on the characteristics of the image. This control is based on the fact that when displaying bright scenes, there is no need to provide a deep black level, and in dark scenes, high brightness of light areas is not needed — th...ese are the features of the human eye. This means that in bright scenes you can increase the overall brightness, and in dark scenes you can reduce it; the maximum brightness difference achievable in this mode of operation is precisely described by dynamic contrast.

The response time can be described as the maximum time required for each pixel of the screen to change brightness, in other words, the longest time from the receipt of a control signal to the pixel until it switches to the specified mode. The actual switching time may be less — if the brightness changes slightly, it can be calculated in microseconds. However, it is the longest time that matters — it describes the guaranteed response speed of each pixel.

First of all, the frame rate is directly related to the response time (see the relevant paragraph): the lower the response time, the higher the frame rate can be provided on this sensor. However, the actual frame rate may be less than the theoretical maximum, it all depends on the TV. Also note that the overall image quality in dynamic scenes depends primarily on the frame rate. Therefore, we can say that the response time is an auxiliary parameter: the average user rarely needs this data, and in the specifications they are given mainly for advertising purposes.

TV support for high dynamic range technology — HDR.

This technology is designed to expand the range of brightness reproduced by the TV; Simply put, an HDR model will display brighter whites and darker blacks than a regular TV. In fact, this means a significant improvement in colour quality. On the one hand, HDR provides a very "live" image, close to what the human eye sees, with an abundance of shades and tones that a normal screen cannot convey; on the other hand, this technology allows to achieve very bright and rich colours.

However for the full use of this feature, you need not only an HDR TV, but also content (movies, TV broadcasts, etc.) that was originally created for HDR. Also note that there are several different HDR technologies that are not compatible with each other. Therefore, when buying a TV with this feature, it is highly advisable to clarify which version of HDR it supports (HDR10, HDR10 + or Dolby Vision). And the following are found:

— HDR10. Historically the first of the consumer HDR formats, less advanced than the options described below but extremely widespread. In particular, HDR10 is supported by almost all streaming services that provide HDR content, and it is also common for Blu-ray discs. Allows to work with a colour depth of 10 bits (hence the name). At the same time, devices of this format are also compatible wi...th content in HDR10+, although its quality will be limited by the capabilities of the original HDR10.

— HDR10+. An improved version of HDR10. With the same colour depth (10 bits), it uses the so-called dynamic metadata, which allows transmitting information about the colour depth not only for groups of several frames, but also for individual frames. This results in an additional improvement in colour reproduction.

– Dolby Vision. An advanced standard used particularly in professional cinematography. Allows to achieve a colour depth of 12 bits, uses the dynamic metadata described above, and also makes it possible to transmit two image options at once in one video stream — HDR and standard (SDR). At the same time, Dolby Vision is based on the same technology as HDR10, so in modern video technology this format is usually combined with HDR10 or HDR10+.

The nominal power of the sound produced by the TV's sound system.

The larger the screen and the greater the estimated distance to the viewer, the more powerful the sound system must be in order to be heard normally. Manufacturers take this moment into account, moreover, most often they also provide a solid volume margin. So if a TV is bought for home viewing in a quiet, calm environment, you can not pay much attention to the sound power: it is guaranteed to be enough for such a usage. It makes sense to specifically look for models with high-power speakers for a noisy environment — for example, a cafe or other public space. Detailed recommendations on this matter can be found in special sources, but here we note that even in such cases, connecting external speakers can be a good alternative.

A decoder can be broadly described as a standard in which digital audio (often multi-channel) is recorded. For normal playback of such sound, it is necessary that the corresponding decoder is supported by the device. Dolby Digital and DTS were the first in multi-channel decoding, gradually improving and introducing new features. The final stage for 2020 is Dolby Atmos and DTS X decoders.

– Dolby Atmos. A decoder that uses not a rigid distribution of sound across channels, but the processing of audio objects, due to which it can be used with almost any number of channels on a reproducing system — the sound will be divided between channels so that each audio object is heard as close as possible to its proper place. When using Dolby Atmos, ceiling speakers (or speakers facing the ceiling) are highly desirable. However, in extreme cases, you can do without them.

— DTS X. An analogue of the Dolby Atmos described above, when the sound is distributed not through individual channels, but through audio objects. The digital signal contains information about where (according to the director's intention) the object audible to the user should be and how it should move, and the processor of the reproducing device processes this information and determines exactly how the sound should be distributed over the available channels in order to achieve the required localization. Thanks to this, DTS X is not tied to a specific number of audi...o channels — there can be as many as you like, the system will automatically divide the sound into them, achieving the desired sound. Also note that this decoder allows you to separately adjust the volume of dialogues.

The ability to display on the TV screen "pictures" from several sources at once. Usually, in the picture-in-picture mode, a small window is displayed in the background of the main image (or several such windows), which is displayed in full screen, in it you can see an additional image. One of the most popular ways to use this “multitasking” is to skip commercial breaks in TV broadcasts: for this time, you can switch the main image to a more interesting channel, and leave the ad in the auxiliary window to not miss the end of the commercial and continue watching. It is worth considering, however, that the images for each window must come from different sources — in other words, it will not work to turn on two channels at the same time from one tuner.

Among the features of the TV, first of all, it is worth noting its communication features, which include AirPlay 2, Wi-Fi(in particular Wi-Fi 5 and Wi-Fi 6), Miracast, Chromecast, Bluetooth. As a control, in addition to the classic remote control, there can be voice control, voice assistant. As well as special features in the form of Ambilight from Philips. More about them:

— Airplay. TV support for AirPlay technology, usually in the AirPlay 2 version. Initially, this technology was created to broadcast multimedia content from Apple gadgets (iPhone, iPad, etc.) to external devices, including TVs. At the same time, it allows not only to play such content, but also provides many additional features — broadcasting additional information (title of the sound track, album cover), playback control from the TV remote control, etc. In AirPlay 2, in turn, the "multi-room" format was added — the ability to simultaneously broadcast several signals to compatible devices installed in different places at home (for example, a movie on a TV and an online radio programme on sound system in the kitchen). In addition, in this version, support for voice control via Siri has appeared and...a number of technical issues have been improved (in particular, buffering of streamed content).

— Wi-Fi. The presence of a built-in Wi-Fi module in the TV; the supported version of this technology can also be specified in this section. Nowadays, Wi-Fi can be used both for wireless access to the Internet and local networks, as well as for direct connection with other devices (for example, broadcasting video from a smartphone/tablet). The specific application of the wireless connection may be different, depending on the functionality of the TV; in addition to Internet access, examples include DLNA, receiving or transmitting video via Wi-Di or Miracast, and using a mobile gadget as a remote control. However, almost all models with this feature belong to Smart TV (see above).
As for Wi-Fi versions, the most relevant nowadays are Wi-Fi 5, Wi-Fi 6 and Wi-Fi 6E. Also note that, in addition to these Wi-Fi standards, earlier ones are usually supported — so compatibility problems does not occur.

— Miracast. TV support for Miracast technology. This technology allows you to broadcast video and audio signals via Wi-Fi technology (both to the TV and from it to portable electronics), while both devices are connected directly (Wi-Fi Direct) and do not require additional equipment, and the bandwidth is sufficient for Full HD video transmission and 5.1 multi-channel audio. Some time ago, TVs used a similar WiDi technology, but nowadays it is almost ousted from the market, and most manufacturers use Miracast.

— Chromecast. Chromecast technology allows you to quickly and easily stream video and audio from your smartphone, tablet or computer to your TV. In fact, Chromecast is a network media player, because after setting up this function, you can wirelessly display the video recorded on your smartphone on your TV with just one touch.

— Bluetooth. Bluetooth technology (any version) is used for direct wireless communication between different devices. How it is used on TVs may vary, depending on the functionality of a particular model (and version of Bluetooth). So, it is almost mandatory for Bluetooth TVs to be able to transfer sound to wireless headphones or speakers. In addition, other use cases may be provided: connecting keyboards, mice and game controllers, direct file exchange with a laptop, remote control from a smartphone or other gadget, etc. These details should be clarified separately. As for specific versions, in many models these details are not specified at all — for use for the intended purpose, “just Bluetooth” is enough. However, there are exceptions, and here the following options are relevant for modern TVs:

• Bluetooth v4.0. A version that combines traditional Bluetooth 2.1, a high-speed standard for transferring large files, and "Bluetooth Low Energy" for small amounts of information. All subsequent versions are built on these three components (with various improvements), and v 4.0 was the first where they appeared all together.
• Bluetooth v 4.1. Improvement of version 4.0, in which compatibility with mobile devices of the 4G LTE standard has been improved — so that the LTE and Bluetooth modules do not create mutual interference while working nearby.
• Bluetooth v4.2. Further development of version 4.0; updates that are relevant for TVs include mainly improving the reliability and noise immunity of communications.
• Bluetooth v5.0. One of the key improvements in version 5.0 compared to previous editions of the protocol was the presence of two special “Low Energy” modes – increased range (due to reduced speed) and increased speed (due to reduced range).
• Bluetooth v 5.1. Update of the v 5.0 version described above. In addition to general improvements in the quality and reliability of communication, this update has implemented such an interesting feature as determining the direction from which the Bluetooth signal is coming. Thanks to this, it becomes possible to determine the location of connected devices with an accuracy of up to a centimeter (for example, a remote control).
• Bluetooth v 5.2. The next, after 5.1, is the fifth-generation Bluetooth update. The main innovations in this version are a number of security improvements, additional power optimization in LE mode, and a new audio signal format for synchronized parallel playback on multiple devices.
• Bluetooth v 5.3. The Bluetooth v 5.3 wireless protocol was introduced at the beginning of 2022. Among the innovations, it accelerated the process of choosing the communication channel between the controller and the device, implemented the function of quickly switching between the state of operation in a small duty cycle and high-speed mode, improved the throughput and stability of the connection by reducing the susceptibility to interference. In case of unexpected interference in the Low Energy mode of operation, the procedure for selecting a communication channel for switching is now accelerated. There are no fundamental innovations in protocol 5.3, but a number of qualitative improvements are seen in it.

— Ambilight. Screen backlight technology. In this case, the TV case illuminates the wall/partition located at the back, due to which a blurry halo appears around the screen contour in the colour of changing scenes. This effect visually expands the screen area, making watching TV more enjoyable. There are three types of backlighting in total: classic Ambilight (on the sides only), Ambilight Surround (on the sides and top), Ambilight Full Surround (from all sides). But manufacturers continue to work on improving the backlight. So, relatively recently, the Ambilight Spectra backlight has appeared, in which the colour matching algorithm has been significantly improved and the LEDs themselves have been optimized.

— Voice control. TV support for voice control allows you to dictate certain commands through the remote control. However, not all functions are covered by voice control and recognition accuracy may require re-entering the command. If you need a more extensive range of functions, then pay attention to the voice assistant.

— Voice assistant. For a long time now, device control has been shifting to voice commands. For this, certain interfaces and systems are used. The most popular are Amazon Alexa and Google Assistant, as well as Samsung's own Bixby assistant. For "apple" devices, this is Apple Siri, but this technique is not presented on TVs. At the same time, unlike the voice control function, the voice assistant does not just turn on this or that function, mode, makes it louder, quieter, but allows you to perform certain operations in applications, whether it is to launch the desired clip in Youtube or display the weather in the browser.

The TV's connectivity options are based not only on wireless technologies (described above), but also on a wired connection. In particular, additional video transmission can be carried out through VGA, composite AV connectors . Some of them also provide sound transmission, in addition to which there may be a mini-Jack (3.5 mm) and other ports for communication with external devices. More about them:

— USB. Connector for connecting external peripheral devices. The presence of USB means at least that the TV is capable of playing content from flash drives and other external USB media. In addition, there may be other ways to use this input: recording TV programs to external media, connecting a WEB camera (see same paragraph), keyboard and mouse to use the built-in browser and other software, etc. The specific set of options depends on the functionality of the TV, it should be specified separately in each case.

— Card reader. A device for working with memory cards, most often in SD format. The main use of the card reader is to play content from such cards on a TV; such an opportunity is especially convenient for viewing materials from photo and video cameras — it is in such devices that memory cards are widely used. There may be other ways to use this function — fo...r example, recording from the broadcast or even exchanging files between the card and the TV's storage. It is worth bearing in mind that SD cards have several subtypes — original SD, SD HC and SD XC, and not all of them may be supported by the card reader.

— LAN. Standard connector for wired connection to computer networks (both local and the Internet). Mostly found in models with Smart TV support (including Android TV devices; see related paragraphs). A wired connection is less convenient than Wi-Fi, not as aesthetically pleasing, so manufacturers place more emphasis on a wireless connection, as a result of which the speed indicators of the LAN connector are not indicated, and in some cases may be unacceptable for 4K broadcasts.

— VGA. Analogue video input, also known as D-sub 15 pin. Initially, the VGA interface was developed for computers, but due to the emergence of more advanced standards like HDMI (see below) and technical limitations (the maximum resolution is only 1280x1024, the inability to transmit sound), it is considered obsolete and is used less and less. So it makes sense to specifically look for a TV with such a connector mainly in cases where it is planned to be used as a monitor for an outdated computer or laptop.

– Composite AV input. Analogue input for video and audio transmission. Previously, it consisted of 3 RCA sockets (yellow for video, white and red for audio) and was connected to the equipment accordingly. Now in many models you can find an AV output, which is a single connector in the “headphone” format, to which a tee cable is already connected (check availability in the package).

— COM port (RS-232). A connector originally designed for computer equipment. In TVs, it is used as a service interface: for troubleshooting, updating firmware, adjusting TV parameters and various calibrations, integrating the TV into centralized remote control systems, etc. Note that the COM port may differ in shape and contact group in different TV models. It is often designated as RS-232C.