What is 4K, 8K LED display, one article quickly understand
Nowadays, small-pitch LED screens are widely used in many fields that require professional display of images, precisely because of its proud ultra-high-definition display technology. Relatively speaking, the pixel point is the smallest display unit on the LED display. Improving the pixel value and resolution of the display device is one of the most direct ways to improve the image output clarity, which is also of great significance for the restoration of image details and colors. . The 4K and 8K in the term "5G+4K/8K+AI" that we are familiar with refer to the concept of pixels and resolution. So what is the specific difference between the two?
LED display manufacturers usually define 4K/8K by point-to-point splicing. Technically speaking, the 4K/8K of today's LED displays essentially refers to the physical (horizontal) resolution of high-definition pixels that can be achieved after splicing these displays. rate. Within the scope of the existing screen, the mainstream 4K resolution (4K: resolution includes but not limited to 3840x2160) has 3840 pixels horizontally and 2160 vertically. The multiplication of the two is the physical resolution we often say . 8K resolution is a strict ultra-high-definition resolution. Taking the typical 7680×4320 resolution of 8K UHD as an example, its horizontal and vertical pixels are twice that of 4K, and the total number of pixels can reach 4K screens. Times.
For ultra-high-definition small-pitch LED displays, the smaller the dot pitch, the easier it is to meet the display requirements of 4K and 8K full-HD resolution display terminals in the market. The display effect can also ensure that viewers can watch for a long time at close range without graininess and visual Enjoy more comfort. With the commercial penetration of 5G into all walks of life, the mass-produced 4K small-pitch LED professional TV wall also meets the surround visual experience required by ultra-high-definition displays. It has the advantages of strong reliability, fast heat dissipation, quieter, and obvious energy saving. Selected by provincial large-scale radio and television studios. Of course, in addition to the radio and television industry, the integrated applications of 5G+4K/8K/AR also target areas such as smart medical care, distance education, and command centers, because these places also require functions such as ultra-high-definition resolution, stability and reliability, and low latency.
Although 4K/8K LED displays have the advantages of professional-level picture display effects, in addition to supporting full HD picture output, these devices also need to realize full HD. Relatively speaking, when playing 8K video sources, the display effect will be significantly better than 4K video sources. Although there are currently relatively few video sources matching 4K or even 8K resolution, as the increasingly mature 5G signal makes up for the pain point that 8K video itself needs to carry a huge amount of data transmission, the trend of terminal image display will inevitably move towards high-definition 4K Even 8K, 5G+8K may become the mainstream application combination for large screens of 100 inches or more in the future.
The importance of 4K 60Hz image processing for small-pitch LED displays
When 4K TVs were first launched a few years ago, there were overwhelming advertising and publicity, but the actual experience was not very good. On the one hand, 4K TVs were mixed, and there was a lot of fuss about the panel, signal format, and processing chip. On the one hand, 4K film sources are relatively scarce, and 4K TV has become a display. But this is not the case for the LED display industry. 4K can be said to be the best solution for ultra-clear and small-pitch LED displays.
Challenges of fine-pitch high-end applications
As the technology continues to mature, small-pitch LED displays are becoming more and more popular in high-end display applications due to their own advantages. High-end applications have higher and higher requirements for display effects. For example, some require the best display effects, which must be customized and point-to-point display, that is, the video material must be customized according to the physical resolution of the LED display, and the video signal processing is not scaled. , Point-to-point display, such a single 1080p full HD interface can no longer meet the needs of small-pitch ultra-high-resolution displays.
Traditional non-4K solutions are complicated to operate Before the launch of 4K processors, the industry's common practice was to use multiple DVI output graphics cards to expand the splicing method. As shown below: One difficulty of this scheme is that the operation is relatively complicated, and sometimes it is necessary to perform fusion processing on the seams. This requires professional graphics cards with fusion functions. Another difficulty is the synchronization problem, whether it is AMD, NVDIA flagship graphics cards or fusion It is also difficult to achieve complete synchronization of multiple DVI output ports with functional professional graphics cards, which will cause tearing at the splicing position. Therefore, multi-window synchronization splicers such as LVP86XX are used. The specific wiring diagram is as shown in the figure below. The calculation and synchronization settings of the related fusion belt are relatively complicated and require professionals to operate.
4K processor solution is easy to operate Using 4K processor equipment, only one HDMI or DP interface is needed to achieve the display effect that can be achieved by expanding the splicing of 4 DVI outputs. The PC-side playback operation becomes very simple, and for large-screen systems, the 4K processor LVP609 like Vivo Video converts 4K signals into multiple 1920x1080 resolution DVI outputs, and multiple output ports are fully synchronized. You only need to use a common sending card to load, and finally through the fast splicing function of LVP609, you can automatically complete splicing by simply entering a few parameters. In this way, there is no need to use a 4K sending card that is expensive and does not have scaling processing, and the rich video signal interface that comes with the processor also provides convenience for accessing different devices.
The difference in 4K signal itself
Regarding true and false 4K, it has been hyped for a while in the 4K TV field. 4K refers to the resolution of 3840x2160 or 4096x2160. A signal with a width less than 3840 cannot be called 4K, and a signal with a height less than 2160 cannot be called 4K. The same 4K signal also has different differences, such as whether the frame rate is 30Hz or 60Hz, the color space is YUV or RGB, etc. These bring obvious contrast in the image quality of the LED display with very good display effects.
The maximum frame rate of the HDMI 1.4 standard is 30 Hz, that is, 30 frames of images are transmitted per second, and the maximum of this parameter of HDMI 2.0 is 60 Hz, that is, 60 frames of images are transmitted per second. The parameter of 60 frames is twice as high as 30 frames, and the picture quality and details are better. The higher the number of frames, the smoother the picture. The intuitive experience is best reflected. When the angle of view is moved quickly, the afterimage of 60 frames is much less than 30 frames, and the value High, the closer the picture is to the real world observed by the human eye. Color space is also a very important parameter. RGB and YUV formats are the most widely used. YUV has different sampling formats such as 4:4:4, 4:2:2, 4:1:1, and 4:2:0. Among them, RGB and YUV 4:4:4 have richer information and better colors, but they have very high requirements on storage space and transmission bandwidth. In order to save bandwidth and storage space in several other ways, colors are compressed.
The difficulty of 4K 60Hz processing lies in the large amount of data and high bandwidth. The common dot frequency of 1920x1080 60Hz is 148MHz, while the dot frequency of 4K 60Hz is 594MHz, which requires high signal transmission and processing. For the LED display, it is also required that the signal transmission and processing can not be frame down, and the DVI output ports must be completely synchronized. Therefore, up to now, LVP609 is the only real 4K 60Hz LED video processor that supports RGB\YUV 4:4:4 format in China.
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