Everyone is talking about 8K video – the new industry standard, TV refresh, highest resolution and exceptional sharpness. We were still amazed at the possibilities of 2K, then 4K – and then a massiv upgrade came along? Read about all this in our article, dotting the i’s in questions about 8K.
1. What is 8K video?
8 K video is a recently emerging video standard (capturing, encoding and displaying a signal). First of all, and this is reflected in its name, we are talking about the image resolution. 8K is the approximate number of horizontal dots in the picture (in fact, there are 7,680 of them). With a standard 16: 9 aspect ratio for a modern TV, the 8K resolution is 7,680 × 4,320 pixels. But the format’s features are not limited to resolution. Video in grade 8 belongs to the Ultra HD class, to which 4K video also belongs, which means that the requirements and capabilities of this format fully apply to it – high dynamic range HDR, increased frame rate and wide color gamut.
2. What is image resolution?
Video is a sequence of frames (static images) that change at a certain speed. A digital picture consists of many dots (pixels), each of which is characterized by color and brightness. The number of these points in each frame determines the video resolution. It all started with standard definition (SD), which is 720 x 576 pixels for PAL TV broadcast and 720 x 480 for NTSC.
It is in this resolution that material on DVDs was encoded. Later, the HD (HD Ready) standard with a resolution of 1 280 x 720, as well as Full HD with the parameters 1 920 x 1 080, appeared, which became a real milestone in the development of video technology. This standard formed the basis for Blu-ray optical discs and became widespread in television broadcasting and subsequently in video streaming. Besides,
But progress does not stand still, and after some time, the 4K or Ultra HD video standard appears, which offers a picture resolution of 3 840 × 2 160 pixels. It is this standard that is now the basic one for content producers and broadcasters, as well as for manufacturers of display devices and media for content reproduction. Some time ago, the 8K video standard was launched with a frame resolution of 7 680 × 4 320 pixels.
Traditionally, it all started with display devices. It was televisions that have always been the locomotive of technical progress in the field of picture resolution, since they could offer a better image even when displaying content at a lower resolution than the screen parameters.
3. What is HDR video?
Along with the resolution, the Ultra HD video standard, which includes both 4K video and 8K video, has included the HDR (High Dynamic Range) video format, which provides a wider brightness range between the darkest and brightest parts of the frame. … An HDR image is perceived to be brighter, more contrasty, and has richer colors.
4. What is frame rate (FPS)?
To display motion on the screen, it is necessary to display a sequence of frames on it at a certain constant speed. Due to the inertia inherent in human vision, the movement on the screen appears to be continuous and smooth – the brain perceives the sequence of pictures not discretely, but as a continuous stream. But, of course, the decisive factor here is the speed with which the frame changes on the screen.
Today, most films are shot at 24 frames per second, which is due to the parameters of still film cameras. For shooting television programs, a speed of 25 frames per second for the PAL standard or 30 frames per second for NTSC is used. With the transition to digital, it became possible to increase the frame rate. Moreover, in the digital world, this frequency does not have to be constant. So in video games this parameter can vary within a fairly wide range and reach 120 Hz in modern implementations. It is clear that with an increase in frequency, the smoothness and fusion of movements increases.
Cinematography is also beginning to experiment with this parameter. So, the version of Peter Jackson’s trilogy “The Hobbit” is available in HFR format with a frequency of 48 frames per second. Rumor has it that James Cameron is filming the two sequels to Avatar at 60 frames per second. The Ultra HD video standard, including 8K video, supports the full spectrum of frequencies – 24, 25, 30, 48, 50, 60, and 120 frames per second. the version of Peter Jackson’s trilogy “The Hobbit” is available in HFR format with a frequency of 48 frames per second.
Rumor has it that James Cameron is filming the two sequels to Avatar at 60 frames per second. The Ultra HD video standard, including 8K video, supports the full spectrum of frequencies – 24, 25, 30, 48, 50, 60, and 120 frames per second. the version of Peter Jackson’s trilogy “The Hobbit” is available in HFR format with a frequency of 48 frames per second. Rumor has it that James Cameron is filming the two sequels to Avatar at 60 frames per second. Ultra HD video standard, including 8K video, supports the full spectrum of frequencies – 24, 25, 30, 48, 50, 60 and 120 frames per second.
5. What is gamut and color depth?
Traditionally, the ability of video technology to capture, process and display colors is evaluated on a chromaticity diagram (color locus). This diagram is a shape called a locus, which is located along two axes with a coordinate grid. All colors visible to the human eye are inscribed in the space enclosed by the contour of the locus. The color saturation changes horizontally, and its hue vertically. That is, any color can be defined using two coordinates. The colors with the maximum saturation are located along the perimeter of the locus, and the least saturated and white in the center.
Various video standards are characterized, among other things, by the color gamut defined by a part of the color locus – within this area are the shades available in this video standard. The Full HD standard used the Rec.709 color gamut as a base. For Ultra HD, including 8K video, the Rec.2020 color gamut is defined, which provides a much richer color gamut. In addition, the Ultra HD standard offers increased color depth (the bit depth of the color shading encoding). Typically, 8 bits of data are used to encode each of the three base colors (RGB). That is, you can define 256 shades for each color. Thus, the palette with 8-bit encoding is 16.8 million colors. The Ultra HD standard allows 10-bit and 12-bit color coding, that is, the palette expands to 1 and 68,
6. Is there a noticeable difference between 4K video and 8K video?
Since HDR’s high dynamic range, higher frame rate, and wide color gamut apply equally to 4K and 8K video, the difference between these standards is determined by the picture resolution. An 8K video frame uses four times as many pixels as a 4K video frame. How much this fourfold difference will be visible to the viewer depends on two factors – the size of the screen and the parameters of the source material. The screen size determines the “size” of each pixel – with the same screen diagonal, the higher the resolution, the smaller the pixel, which means the picture is perceived as smoother and more consistent. Thus, there is a certain threshold value of the screen diagonal, above which the difference in resolution will be noticeable. Of course, this threshold is largely subjective and depends on the individual characteristics of vision, but on average in our experience, the difference in picture quality between 4K and 8K is already visible on a 65-inch screen. The second factor is the quality of the source material. It is clear that this factor only comes into effect if you compare the picture on a 4K TV when playing 4K video and, accordingly, on an 8K TV when playing 8K video. In this case, the difference will be maximum. But the problem is that 8K content is still negligible, and most likely you will be watching 4K or even Full HD video on an 8K TV. Again, the difference will be less obvious. on an 8K TV when playing 8K video. In this case, the difference will be maximum. But the problem is that 8K content is still negligible, and most likely you will be watching 4K or even Full HD video on an 8K TV. Again, the difference will be less obvious. on an 8K TV when playing 8K video. In this case, the difference will be maximum. But the problem is that 8K content is still negligible, and most likely you will be watching 4K or even Full HD video on an 8K TV. Again, the difference will be less obvious.
7. Why do I need to compress a video?
As you can see from the above, the 8K video standard requires much more data processing and transmission. Quadrupling the resolution of 4K, higher frame rates and higher color depths are driving a dramatic increase in volume. Digital video, unlike audio, has never been used uncompressed, and video compression algorithms need to be improved to meet the technical constraints of storing, transporting and processing ever-growing amounts of data. The Full HD standard used the H.264 or AVC (Advanced Video Coding) codec. When developing the 4K standard, they used the H.265 or HEVC (High Efficiency Video Coding) codec. According to the participants of the 8K Video Summit, when using HEVC for 8K video, it is required to provide an average bitrate of the stream when broadcasting 84 Mbps., and the generally accepted recommendation for successful decompression requires providing 120 Mbit / s, which with the current development of technology is an intractable task. For this reason, a new codec was adopted for the 8K standard last year – H.266 or Versatile Video Coding (VCC). An important point is that a more efficient codec requires higher processing power from both encoding devices (video cameras) and decoding devices (players, televisions, projectors).
8. Is there real 8K content now?
Now 8K videos can be found on YouTube and also some streaming services offer single releases in this resolution. Moreover, these positions are often the result of upscaling from the 4K source. Thus, we can say that there is practically no video content with real 8K resolution today. At least, it is not necessary to talk about the possibility of watching 8K on a more or less constant basis now. 9. Then what to watch on 8K TV today? Exactly the same as what you watch on a 4K TV or projector. As noted above, on large diagonals, the advantage of 8K resolution becomes evident even on 4K and Full HD material. Modern video processors and video scaling technologies work wonders, and your familiar films will appear in a new form until the last frame.
10. And tomorrow? What are the prospects for 8K video?
Predicting the development of the 8K video format, we can assume that we will not see optical discs with such video soon, if ever, and the distribution of such content will go through streaming channels and through game consoles. Content producers act as a serious limiting factor here – film studios, even at 4K as the basic standard, have not yet fully switched over and the lion’s share of production is led to 2K. What can we say about 8K. Although, there are glimpses here too – for example, James Gunn used the newest Red Dragon Weapon 8K VV camera when filming the second part of “Guardians of the Galaxy”. True, in the end, at the production stage, the resolution of the material was reduced to 4K, but the fact itself inspires hope. Fifth-generation (5G) cellular networks can also play a role in promoting 8K video.