To say that in the past two years, what technology makes you feel but it is difficult to use back, most people must first think of high brushing, the high brush of mobile phone screen makes our use experience more smooth and pleasant. We also hope that the devices around us can have the characteristics of high brushing, and continue the coherent and clear visual experience.
Nowadays, there is no high-definition high-brush "antique", it is difficult to meet our increasingly demanding purchase needs. Consumer-resistant products such as TV, long replacement cycle, and support for high-specification playback formats, you can get a better viewing experience, so high-specification TV parameters such as 4K 120Hz have become the inevitable features of new TV, which is the fundamental way for TV to fight the future.
But have you ever thought that the 120Hz TV high brush experience you are most looking forward to and most willing to add money to get may also become your IQ tax for reverse upgrading.
One key to open 120Hz, simply numb?
In each TV has a very eye-catching function introduction, what "one key to open the rapid refresh", "double 120Hz multiplication technology", "track mode", movie transmission", "speed of light refresh mode", etc., these slogans stimulate our desire to buy this TV, but in the upper right corner of this 120Hz high brush technology, there may also be a small "*" number, and the "*" inside the secret pocket notes are often easy for us to ignore, and especially should be screened information.
So what is hidden in this 120Hz "*"?
We counted low-, mid-to-high-end TVs, for products with special notes on high-brush technology, the "*" number is often like this:
120Hz high brush is based on XXXX high dynamic refresh technology;
120Hz lightspeed refresh mode subsequent system upgrade can be realized;
Translating these annotations into words, that is, the high brush of our TV is based on the high brush algorithm technology of the system software. If you don't understand it, then we translate it more bluntly: our TV hardware does not support high brushing, or can not reach the advertised high brush frequency, and can only use software algorithms to achieve it.
If the algorithm can be comparable to the hardware-level high brush, it will be a good thing for everyone to save money and have a better movie viewing experience. But according to the current high brush technology, it is achieved at the expense of picture quality.
Why the high brush algorithm hurts image quality
4K 60Hz refers to the 60 refreshes per pixel per second on a resolution screen of 3840×2160 (later known as 4K*2K). To achieve the original chip computing power and hardware parameters unchanged, each pixel in a second to refresh 120 times, the only thing that can be done is to reduce the number of rendered pixels. This kind of plot is like practicing copying as a child, in order to finish the homework quickly, we will take two pens to copy, and the time can be reduced by half. Television engineers may have been inspired by their childhood to apply this stunt to television.
The current high-brush "transcription" algorithm also has two schools, one is called DLG and the other is called HSR.
DLG technology is to reduce the rendering accuracy of portrait pixels, only render odd rows (or even rows) such as 1, 3, 5, 7, 9, and then copy the data of the technical rows to even rows of 2, 4, 6, 8, and 10 for display. At this time, the number of vertical refreshes is reduced by half, so the refresh time is reduced by half compared to the original, so at a resolution of 4K*1K, the refresh rate can be increased to 120Hz.
However, in the portrait quality, every two rows of pixels are consistent, which will also lead to a decrease in the longitudinal resolution, an increase in the sense of aliasing in the picture, and an increase in the actual 4K image quality. Just like when copying, the handwriting copied with 2 pens is certainly not as capable as holding a single pen.
Of course, the algorithm can be upgraded, compared with DLG technology, the TV using HSR technology, the display effect is relatively better. The basic principle of HSR and DLG is similar, similarly compressing longitudinal pixels, rendering only odd rows (or even rows), while even rows fuse information from adjacent two rows for display.
It can be understood as an improved version of double-pen copying, by adjusting the thickness and angle of the second pen, so that the glyphs of the two lines are different, which is not easy for the teacher to find. Therefore, compared with DLG technology, the picture using HSR technology will make the color and line of the entire picture more natural after the fusion of even lines of pixels, and the clarity will be correspondingly improved.
Fast, there is a price to pay. Compared with the original 4K picture quality of the "transcription" algorithm, the display effect of using the algorithm to pull up the refresh rate is definitely greatly reduced.
Moreover, it is not only 60Hz to 120Hz that will have the problem of image quality attenuation.
According to the upstream panel supply information, the mainstream TV panel mainly has two refresh rates, 4K 60Hz and 4K 120Hz. Therefore, there are some TVs that claim to be able to achieve 144Hz or even higher refresh rates, which need to be achieved through algorithms. The negative effects brought about by high brushing, before buying this type of TV, we must weigh and accept.
What are the "pits" of 120hz TVs?
Since the 120Hz marked "*" will step on the pit, is it not ok to avoid this type of TV? Not really. Some low-end TVs on the market hang sheep's heads to sell dog meat, using "algorithmic" screens, but firmly claim to be 120Hz screens.
There are also some TVs with inadequate specifications, such as the use of 4K 120Hz screens, but the chip does not support full-channel 120Hz decoding, when the TV encounters a 120FPS source, it cannot be decoded or will automatically drop to 60Hz output.
Even if some TVs use qualified screens and chips, but the interface is only HDMI2.0, or the blood version of HDMI2.1 (bandwidth less than 48Gbps), for the input of high brush source or experience the screen expansion of high brush games, the TV will reduce the image quality or display at a rate of 60Hz, affecting the experience.
What is the standard for a true 4K120hz TV?
4K 120Hz complete, we call it a full channel 120hz TV. If you want to achieve a full-channel 120Hz display, then the "screen core mouth calculation" needs to meet the requirements, that is, the screen passes through the screen, chip, interface and high brush algorithm 4 levels, and the final display effect reaches 4K 120Hz.
The basis of all 4K 120Hz content display is the hardware-level 4K 120Hz high-brush screen body that the TV must be equipped with; secondly, the decoding chip that decodes and outputs the content can process and output 120Hz content in all scenarios such as HDMI, USB, streaming media, etc.; and in the channel where we play 120Hz content, the hard requirements are HDMI inputs. It should be equipped with a full-blood version of 48Gbps HDMI2.1 interface; finally, it is necessary to process non-120Hz content, and adapt to smooth and clear picture effects through 120Hz MEMC motion compensation and VRR dynamic frame rate adjustment algorithm.
Only when the TV specifications can meet the above conditions can we become the capital of our TV war in the future. However, while referring to these specifications, it is also necessary to consider other details, such as when choosing a high-brush TV with LCD panels, the response time of the LCD panel needs to reach less than 8ms to meet the refresh rate of 120Hz; for example, choose to be equipped with high-specification 5G WIFI to adapt to the future increase in streaming media bit rate.
Look at it rationally and welcome the future of 120Hz high brush
We often say that technology always has two sides, in the low-end products to add high brush technology, increase the product experience dimension, increase the amount of non-priced behavior, will certainly be well received by the public; and if in order to catch up with the trend, with the help of high brush technology, thereby increasing product selling points, improve product competitiveness and price, these specifications of the product is the need for consumers to carefully identify.
Objectively speaking, the most widely used 120Hz high brush is still in the game field, and the high brush film and television field that everyone most often contacts is still in the development stage. However, as a consumer-resistant product, the update cycle is generally about 5 years, so when consumers buy a TV, it is not impossible to choose a full-channel 120Hz TV for the future to make technical reserves. However, for families who only watch movies in pot dramas, high brushing is not just needed, and we must not jump into the consumption trap. If you look at the 60Hz plug 120Hz TV, you also need to pay attention to whether the TV is full channel 120Hz display, whether the high brush function can be selectively switched, and whether there is a problem of optimization in place for various playback scene algorithms.
For the development of technology, we should also give a certain degree of tolerance and patience, after all, many emerging technologies are jointly formulated and promoted by relevant departments and industries, and it is difficult to achieve in the short term. At this time, it is more necessary to enhance the brand's self-restraint and bring better product experience to consumers and users.