Recently, some of the friends in the group wanted to buy TV and began to explore the various performance and parameters of TV. Here's a more mysterious indicator, HDR, which we'll explore today in a way that everyone can quickly understand.
High Dynamic Range Imaging (High Dynamic Range Imaging), or HDRI or HDR for short, is a set of techniques used in computer graphics and cinematography to achieve greater exposure dynamic range (i.e., greater difference between light and dark) than normal digital image technology. The purpose of high dynamic range imaging is to correctly represent the brightness of the real world from direct sunlight to the darkest shadows.
That is to say, the high dynamic range of nature is actually very large, the previous TV is difficult to really restore. We all know that the simulation of things are very mysterious, in order to achieve HDR, the entire industry chain must support and follow up. For example, shooting, post-production, coding, distribution, playback display, and so on must be followed up.
In the playback display segment, there are two standards, one is the Ultra HD Forum, which represents the television industry, and the other is the VESA, which represents the display industry.
- Ultra HD Forum defines HDR standards such as Dolby Vision, HDR10, HDR10 plus, and HLG (Hybrid Log-Gamma).
- THE VESA defines HDR standards as: 400, 500, 600, 1000, 1400, 400 true black, 500 true black
This is similar to the wireless transmission standards of 5G and Wi-Fi 6, in fact, the same thing, that is, on behalf of the interest groups are not the same, no one to accept. Anyway, it's all simulated stuff, there's no fixed statement, they're standard.
Speaking of who does not accept who, television manufacturers are even more so, between them are more who do not accept who, like to engage in small groups. Ultra HD Forum also has no way to impose standards based on the strength of their small groups;
- Dolby Vision: Major players SONY, Hisson. High-end players, HDR white rich beauty, not only to pay licensing fees, but also need to add hardware requirements. Developed by Dolby to support dynamic metadata and color depth of up to 12bits, it is by far the best HDR solution. Even if the TV itself supports Dolby Vision, it can only be turned on when content containing Dolby Vision metadata is played.
- HDR10: Major player LG. HDR mainstream because it's free. HDR10 does not contain dynamic metadata and supports only 10bit color depth. Televisions with Dolby Vision usually also support HDR10, but vice versa.
- HDR10 Plus: Major player Samsung. The enhanced version of the HDR10, Samsung and Amazon, has to be special. This standard supports dynamic metadata and solves the problem of highlight overflow of HDR10 screen.
- HLG: I haven't seen it yet. HDR standard for digital TV signals developed jointly by the BBC and NHK. It is characterized by compatibility with SDR (Standard Dynamic Range) content.
It can be understood that support for an HDR standard is only software support on, because the image is originally a simulation of the restoration of the technology, specific to the display effect of the restoration, or to watch TV display itself. It is as if a candidate got the pass (software to open HDR standard) can enter the exam, the specific number of points can also depend on their own strength.
- For example, backlighting:
HDR requires blacker black, whiter whiter, and you need partition backlighting. And the TV screen is already random, your backlight fit good or bad will obviously affect the display effect. Side-in backlighting is not mentioned, straight-down backlighting is divided into two types, one is the number of lamp beads is less, such as 9; The gap is too big to be a cost at all. The most cattle is a pixel corresponding to a backlight, is not OLED, but very expensive.
- For example, brightness:
For example, a TV is only 400 nits, barely an HDR standard, don't mention any good HDR effect. Brightness is the higher the better.
- Color field and color depth:
The color field of this thing, depending on the spectral characteristics of the backlight and the extent to which the filter matches the backlight, the pure analog tuning of things, and panel parameters, must be measured to know good or bad. After testing, we know exactly how much coverage a TV covers the color field standard. Color field coverage is generally QLED> OLED> LED
The color depth is n bit, which corresponds to the gray scale of 2^n. HDR 10bit files, your panel is best to support 10bit, but also high-end TV only.
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