Just what is HDR? HDR stands for High Dynamic Range, and it is one of the most recent developments in the video world (photography has had the technology for a while now, but it works slightly differently). With HDR content you get a vastly expanded range from darkest dark to brightest bright and a significantly improved color gamut (range of colors possible to represent on a display).
Types of HDR Technology
There are currently 3 major types of HDR playback technology, and they both come with their own set of standards for what constitutes HDR compatibility with a given display make and model. The 3 types of HDR standards are HDR10, Dolby Vision, and HLG.
HDR10 Media Profile
HDR10 Media Profile is the most common type of HDR found on modern displays. With HDR10 you can expect an expanded color gamut and a large contrast ratio. HDR10 uses static metadata encoded information to tell the display what brightness value to apply for the content being displayed. It is part of the UltraHD Premium Standard and every single display that says it is HDR capable will be able to playback HDR10 content.
However, just because your display can decode the HDR10 metadata and display an image does not mean that your display can display those images at the full HDR10 standard.
In order for you to be able to get the full benefit from an HDR10 display, your display must reach one of the two HDR10 standards. But, before we can describe those two standards we will first have to get a little terminology out of the way.
- Nit(s) – a single nit of brightness is equivalent to one candela per square meter (1cd/m^2). In other words, the amount of light that a single candle can create in a one-meter by one-meter box.
HDR10 Standard 1
For your display to reach Standard 1 it has to meet the following criteria:
- Support a nit brightness range of 0.05nits to 1000+nits
HDR10 Standard 2
For HDR10 Standard 2 your display must have:
- A nit brightness range of 0.0005nits to 540+nits
While not really a fourth type of HDR, HDR10+ still deserves a mentioning on this post.
The only difference between regular HDR10 and HDR10+ is that HDR10+ supports dynamic metadata (just like Dolby Vision HDR). It still conforms to the same standards as HDR10, but can handle lighting on a scene-by-scene basis. HDR10+ will be a free firmware update when it becomes available in your region.
The first major difference between HDR10 Media Profile and Dolby Vision (other than name and intellectual property copyright holder) is that Dolby Vision displays support dynamic metadata to tell the display what brightness range to apply to the content on a scene-by-scene basis. What this means is that in addition to the expected brightness range and color gamut you can expect scene-by-scene tailored brightness for any piece of Dolby Vision content you pass to your display.
The only major caveat with Dolby Vision is that for a display manufacturer or content creator to use the standard they have to first pay a premium to Dolby. This means that the variety of displays and content that support the standard is limited to those that can afford to pay Dolby for the rights to utilize their standard. That is unfortunate, really, because the dynamic metadata used by Dolby Vision can create a much, much, much more immersive media absorbing experience.
HLG – Hybrid Log Gamma
HLG (Hybrid Log Gamma) HDR is one of the newest HDR formats to find it’s way into your television screen. Created by the BBC (British Broadcasting Corporation) in conjunction with NHK Japan (a Japanese broadcasting corporation), HLG HDR aims to solve a relatively new problem: HDR for broadcast television.
Basically, what makes HLG HDR so special is that it takes the SDR (Standard Dynamic Range) signal and stacks an HDR signal on top of it all in the same data stream. This helps broadcasters simultaneously broadcast in both HDR and SDR without having to have a separate broadcast channel or programming schedule.
This isn’t the End of the HDR Story
Well, there you have it: a quick summary of the different HDR formats for home video. We here at That AV Dude have definitely skipped over some of the more technical aspects of the technology, but who’s to say that we won’t dive into that ocean of facts and figures in a future post?
Have anything to add to the HDR story? Want to correct something we got wrong? Let us know in the comments below!
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