vivo X21 UD Review: Display One Small Step for vivo
Author:Soomal
Source:eng.soomal.com

Rate:10.00/20

Although vivo Apex, a concept smartphone released on the MWC2018 with a large number of advanced designs, earned enough attention, in the mainstream market, the latest mass production mobile phones are still a lot of pragmatic. vivo X21 starts at 2898 yuan, only 100 Yuan more expensive than the the X20, provides 2GB of RAM more and MicroSD storage expansion. Soomal believe that most rational consumers will more willing to choose the new one, and to spend 600 yuan more to buy the only under display fingerprint identification version. In addition to the of fingerprint technology, another highlight of the X21 is the screen.

Vivo X21 uses Samsung's flexible AMOLED panel, full-vision design, 6.28-inch with resolution of 2280x1080 count for 402PPI. Because the AMOLED sub-pixels are arranged in a diamond-shaped Pentile type, the actual pixel density is lower compared to the RGB array of TFT panels. With the rounded corners and the Norch, the X21's screen-to-body ratio increased to 90%.

About ICC

Of course, the hardware specifications are not the cause of X21's display screen attracting us. Due to price reasons, the display screen hardware potential of this phone is far less than the former Galaxy S9, but how to make full potential of OELD's color and high contrast advantages? Most cell phone manufacturers simply ignore the problem. Vivo announced at the X21 conference that it has joined the member organization of the International Color Consortium, icc. Icc is an analog and digital color display management organization jointly formed by Adobe, Agfa, Eastman Kodak, Apple, and Microsoft. The main objective of this alliance is to provide uniform color management standards for the production, display, playback, and other aspects of hardware production and software development for analog and digital images, and to reduce color loss due to differences in hardware and software. Its members are also mainly software hardware manufacturers or professional research institutions related to digital color and display.

The most typical application of icc technology is that professional users and enthusiasts to use the various standard and home-made icc Profile files for color correction. This is totally free and open, and everyone is available. For example, the most simple to use Spyder, X-Rite and other device software in the Windows or MacOS comes with screen calibration function for grayscale and color correction, the final correction data is saved on the ICC for reference and backup.

Brands=NIKON;Model=NIKON D800E;Copyright=Nicolas Cornet;Photographers=Nicolas Cornet;Focal Length=16mm;Focal Length In 35mm Format=16mm;F-number=F8.0;Metering Mode=Pattern;ISO Speed=ISO200;White Balance=Auto;Contrast=Normal;Saturation=Normal;Sharpness=Normal;Exposure Bias Value=0.0EV;Exposure Time=1/8seconds;Exposure Program=Manual;Scene Capture Type=Standard;DateTime=2012.08.08 22:07:18
Brands=NIKON;Model=NIKON D800E;Copyright=Nicolas Cornet;Photographers=Nicolas Cornet;Focal Length=16mm;Focal Length In 35mm Format=16mm;F-number=F8.0;Metering Mode=Pattern;ISO Speed=ISO200;White Balance=Auto;Contrast=Normal;Saturation=Normal;Sharpness=Normal;Exposure Bias Value=0.0EV;Exposure Time=1/8seconds;Exposure Program=Manual;Scene Capture Type=Standard;DateTime=2012.08.08 22:07:18

In addition, the icc file plays an important role in the color consistency between different color standards. For example, under different color gamut, the same RGB color code would different colors. To correctly display a sRGB image in a wide color gamut screen, it is necessary to remap the color of the image by loading the icc profile in advance. For example, the above two A picture needs proper color management to display it correctly. By using icc to convert the corresponding color code to an approximate value that can be correctly displayed, dynamic ICC can theoretically let you enjoy photos of different color gamut simultaneously on a web page. However, since most professional monitors provide a variety of commonly used preset modes such as sRGB forcing conversion, the ability to convert image colors through ICCC is less likely to be used.

An enterprise joins ICC member, meaning that it recognizes the importance of ICCC for consistent color display, and will adopt it in hardware and software development. This is also positive for mobile phone manufacturers. Little domestic mobile phones have display management. The same photo display on these inconsistent screens differs great, which brings two problems:

First, which screen should be choosing when people are assessing the color and quality of different mobile phone photography imaging, if both do not have color management. A rational assessment is to export the photos stored on the mobile phone to a high-end professional device. The consistent display is not only for mobile phone users to show off their shooting technology and scenery cuisine, but also for the mobile phone manufacturers to develop a unified and controllable objective evaluation criterion in the development of camera imaging technology, avoiding falling into the self-inflicted and encumbered prison. Another problem caused by out-of-control display is that the overall interface design of the system is inconsistent with the reference color, resulting in the final display on the screen of the mobile phone deviating from the artistic intention of the artists and designers.

X21's icc function and system display settings

Our ICC introduction here is to tell you that consistent reference color display is necessary for both users and manufacturers. Joined icc means vivo needs to come up with a reference to the icc device, which is naturally X21. The X21 is a standard P3 wide color gamut display, which is also the maximum advantage of the P3 color gamut camera for the camera. At the same time, the built-in photo album tool supports icc profile to correctly display the colors of the sRGB images, and is more compatible with the network photos, avoiding the common dazzling when the wide color gamut screen displays bright colors.

Display color options in X21 are still relatively less, Funtouch OS 4.0, based on Android 8, does not have a global sRGB mode, while eye protection mode, aiming to reduce the screen color temperature, varies greatly, for users can adjust between 2500K-7000K. So, in the end can X21 achieve the requirements of the icc standard? By convention, the screen objective test is done by Spectra Cal Calman. If there is no special explanation, the screen indicators are the test results of the standard dynamic range display mode of SDR.

In the default mode, the color temperature of X21 is still higher than the 6500K standard. In addition to the gamma value close to the standard of 2.2, the overall indicator does not improve significantly. Of course, since the color dynamics of red are no longer deliberately compressed, the "normal" vivo phone came back. Fortunately, like the OPPO R11s Plus, the X21 can be adjusted to nearly 6500K standard color temperature using eye protection.

Comparision vivo X21 R11 Plus OnePlus 5t X20 Plus Huawei Mate 10
Brightness cd/m2 394 414 414 418-511 402-630
Grayscale (Gamma 2.2) 2.23 2.25 2.32 2.06 1.99
Average Color Temperature K 7616 6624 6385 7450 6667
Average Luminance Error 5.91 1.6 1.94 5.73 2.26
Comparision vivo X21 R11 Plus OnePlus 5t X20 Plus Huawei Mate 10
Color Gamut(sRGB) 129.73% 135.89% 128.47% 97.99% 92.48%
Average Color Error 4.08 3.25 5.9 2.4 2.66
Largest Color Error 9.61 7.03 9.63 3.75 4.62
Comparision vivo X21 Samsung Galaxy S9 iPhone X Galaxy Note 8 iPhone 8 Plus Galaxy S8+
Brightness cd/m2 394 344-659 530-649 406-505 545 399-500
Grayscale (Gamma 2.2) 2.22 2.16 2.22 1.92 2.21 2.29
Average Color Temperature K 6591 6467 6638 6225 6974 6324
Average Luminance Error 2.2 2.32 1.53 3.40 6.42 2.58
Comparision Galaxy S9 Galaxy S9 iPhone X iPhone 8 Plus Galaxy S8+
Color Gamut(sRGB) 102.48% 103.27% 100.5% 102.77% 98.99%
Average Color Error 1.85 1.4 1.15 3.64 3.01
3.45 Galaxy S9 2.9 2.09 8.1 5.05
  • Max Screen Brightness (cd/m2 or nits): The maximum brightness one screen could reach, without considering glass quality, algorithm or dynamic adjusting. Over 500 cd/m2 can be used under strong light, below 400 cd/m2 will be to use.
    Gamma 2.2: Gamma value is the key factor in contrast display. Our eyes do not perceive light the way cameras do. Under sRGB, if the gamma value is 2.2, the tonal range is just what human eyes receive. Lower than 2.2, the contrast will go down, otherwise, it will go up. Except the gamma value, we have to see form the picture if the red, green and blue curve overlap, if not, different color contrast will be different. The value between 2.1 to 2.3 is qualified for display, while if the value is below 2 or over 2.4, the contrast will be lower or higher than standard.
    Average Color of White: The average color temperature in degrees, D65 with 6500 K is the standard color of White for most Consumer Content and needed for accurate color reproduction of all images. Higher than 6500K will tend to be cold, otherwise will be warm.
    Color difference: A measurement used to indicate how much a color deviates from standard. The higher the E, the more inaccurate the color. This is because the human eye is only capable of detecting color difference at certain thresholds. It is hard to detect if average E is below 5, less than average 3 E and less than 5 E is excellent, the smaller the E is, the better the color is. Between 5 to 10 E is detectable, over 10E is significantly detectable.
    Color Gamut(sRGB): The specific range of colors that one device is able to display. Our test is based on sRGB. If wide-gamut device is tested, Adobe RGB or NTSC gamut will be noted for reference. Display with over 90% will be enough for everyday use, higher than a certain percentage will not affect using experience significantly. However, photo playback requires precisely range, 10bit video requires wider gamut.
    Restricted by our devices, we will not test the viewing angle. On average, more than 30 would bring over 50% brightness loss.

On the Android platform, switching in developer mode can help wide color gamut screens to display sRGB colors to switch, which method is adopted by Google Pixel, Sony, OnePlus and other mobile phones. Although abnormal color display displayed, this preset conversion method will cause color loss, and it will not be able to properly restore warm colors such as red. Samsung, Xiaomi, etc. solve this problem by providing sRGB presets.

In the vivo X21, the same consistent sRGB color display effect can also be obtained through the icc conversion. After adjusting the color temperature, the overall grayscale, color performance, and contrast of the X21 are excellent, and the P3 can be correctly displayed when viewing the picture. And sRGB photos, with better color reference, but also far more than any previous vivo phone, performance is no worse than Microsoft, Apple and Samsung's mobile devices. In outdoor use, the vivo X21's peak brightness can exceed 450nits. X21s image transparency, viewing angle are the same with X20. Although the peak brightness is far from the iPhone X or S9 and other flagship mobile phones, the readability of the screen content in the outdoor performance is not bad, and the overall color, brightness and grayscale performance are far better than the LG OLED panel used by the current Google Pixel series.

Since the ICC conversion is only effective in its own photo app, in the third-party applications, the P3 wide color gamut will still affect the display of web pages, social networking and third-party image apps, and the bright color is still dazzling. On the system interface, due to the full use of the P3 color gamut standard, the dynamic behavior of icons and background colors is no longer as intense as the previous vivo phones. Manufacturers also said that they will gradually increase compatibility in the future. Of course, if vivo can directly provide a global sRGB mode switch will be better. In fact, iPhone X, iPad Pro in addition to the system comes with photos and browser applications, the third-party applications are also convert to sRGB display, some loss of color dynamic, but good compatibility is also worth a technical reference.

The full application of dynamic ICC loading is a daunting technical problem on PCs. The adaptation of various types of third-party mobile applications on mobile phones is even more difficult. X21 is just starting out, but it is a solid first step, and a huge improvement for vivo. However, as the limited hardware, vivo smartphones brightness, HDR and other functions cannot compete with the big brand flagship models.

The icc Profile technology standard adopted by the vivo X21 is higher and harder to implement in color consistency applications. This not only brings first-class color display, but also really brings high compatibility difficulty. We also hope that manufacturers can Keep on good technical taste. In addition, since it is already an ICC member, it should not bother users to adjust color temperature by themselves.

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