The era of High Dynamic Range video is officially upon us, now that Ultra HD Blu-ray has arrived on the market and streaming services like VUDU, Netflix, and Amazon are actually streaming HDR content. What is HDR video? For that answer, I'll point you to my previous story on the topic, High Hopes for High Dynamic Range (HDR) Video.

If you've been following the introduction of HDR-capable TVs, especially over the past six months, you've probably seen the words "Dolby Vision" and/or "HDR10" in reference to the type of HDR technology that a certain display supports. That's right, there are two different HDR technologies (actually, there are more than two, but we're going to focus here on the two primary ones being incorporated into new TVs from the major U.S. manufacturers). And we all know what that means...format war!

It's been awhile since we had a nice, juicy CE format war to write about. As always, format wars create a lot of confusion, especially in the technology's infancy. We're going to try and clear up some of that confusion here with an overview of each format: what it is, who is supporting it, and what hardware/content is currently available. We'll provide some basic technical details of each format; if you want more in-depth technical info, check out the links down in the Additional Resources section.

Dolby Vision
In 2007, Dolby purchased a company called BrightSide Technologies and developed the first HDR display prototype. Since then, Dolby has continued to refine the technology and officially unveiled Dolby Vision at CES 2014. Dolby Vision actually represents a complete package of technologies involving dynamic range, color, and resolution. At its heart is a new electro-optical transfer function (the method of converting a signal to visible light) called Perceptual Quantizer (or PQ) that drives and defines the higher dynamic range. DV content is mastered to a specific PQ value. The standard is 10,000 Nits; but, since no display can do that yet, the current DV target is a (somewhat) more realistic 4,000 Nits. Dolby Vision-mastered content also includes up to a 12-bit color depth, up to a Rec 2020 color gamut, and a 4K resolution. (By the way, SMPTE has adopted the PQ electro-optical transfer function and labeled it ST-2084.)

Dolby Vision is a proprietary end-to-end solution, which means you need Dolby Vision-mastered content played through a Dolby Vision-capable source sent to a Dolby Vision-capable display. The benefit to this approach is that every Dolby Vision display includes a chip that identifies its output capabilities (light output, color space, etc.), which it passes to the DV source so that the source can optimize the Dolby Vision signal frame by frame to meet the capabilities of that specific display while still preserving the intent of the original master. The same remapping algorithms are used in all Dolby Vision displays.

Several hardware manufacturers have embraced the Dolby Vision approach. VIZIO and LG now sell Dolby Vision-capable UHD TVs, and upcoming Philips and TCL TVs will also support the format. On the content side, Sony Pictures, Warner Brothers, Universal, and MGM have all partnered with Dolby to offer home video content in the Dolby Vision format. So far, Dolby Vision content is only available in streamed form--through the Netflix and VUDU apps built into DV-enabled smart TVs like VIZIO's Reference and P Series. Netflix's original series Marco Polo is available now in Dolby Vision, and the streaming king recently announced that it would offer 100 hours of DV programming by August. VUDU offers over 30 Dolby Vision titles right now. Amazon has also announced plans to support the streaming of Dolby Vision content, but it's not available yet.

For disc lovers, the news is less positive right now. At this stage, no Dolby Vision content is available in the new Ultra HD Blu-ray disc format. Why is that? Because Dolby Vision is not the official HDR format mandated in the Ultra HD Blu-ray spec; DV is only listed as an optional format. And the only UHD Blu-ray player on the market at this moment--Samsung's UBD-K8500--doesn't support Dolby Vision playback. At least one studio, Universal, has pledged to offer Dolby Vision content on disc when a player arrives that can support it.

And in case you're wondering, Dolby Vision can't be added to a TV or Blu-ray device down the road via a software update. It requires specific hardware.

HDR10
Why didn't Samsung choose to add support for Dolby Vision to its new UBD-K8500 disc player? It's simple really: Samsung is one of the leading supporters of the other HDR format, HDR10.

As HDR moved closer to becoming a viable TV technology, TV manufacturers like Samsung, Sony, and (originally) LG wanted a more open platform than Dolby offered. They probably didn't want to pay Dolby licensing fees, nor did they want to submit to a certification process that takes away some of their control over their own products. So, they began developing their own approaches to HDR video, which eventually evolved into one officially defined profile, labeled by the Consumer Technology Association in August 2015 as the HDR10 media profile.

HDR10 is built around the SMPTE ST 2084 electro-optical transfer function (again, it's the same as Dolby's PQ), and HDR10 content can have similar specs as Dolby Vision content in terms of brightness and color, although the HDR10 profile only lists 10-bit color versus Dolby's 12-bit color. [Editor's note: The original version of the story said that the mastering target for HDR10 is 1,000 nits, but we were informed by a respected source that Dolby Vision and HDR10 are essentially mastered in the same way in terms of nits. It's really dictated by the capabilities of the mastering monitor. Some of the first HDR10 titles were mastered at 4,000 nits, while others were around 1,000 to 1,200 nits.]

The major difference is in how the content is handled at the display end. the HDR10 approach doesn't dynamically map content based on the specific brightness and color output capabilities of a certain TV the way Dolby Vision can, and there isn't a set algorithm to ensure that the color is remapped the same way on every HDR10 display. So, in general, HDR10 is less precise. How that plays out in the real world depends on the specific capabilities/limitations of your TV.

The HDR10 profile has indeed become the format of choice on the vast majority of new HDR-capable TVs. Basically, if the HDR TV doesn't specifically mention Dolby Vision, then it most likely uses HDR10. HDR10 is also the mandated format in the Ultra HD Blu-ray spec, which means every UHD BD player must support playback of HDR10 content.

At CES 2016, HDR10-capable TVs from Samsung, Sony, Hisense/Sharp, Philips, and LG were all on display. LG made the headlines as being the first TV manufacturer to incorporate both HDR10 and Dolby Vision in its OLED and LED/LCD 4K TVs, but Philips also quietly displayed its premium 8600 Series that includes both technologies. CNET's David Katzmaier recently reported that VIZIO will follow suit and add HDR10 support via firmware update to its Reference Series, as well as its new P Series UHD TVs.

On the software side, Netflix is actually streaming content in both HDR10 and Dolby Vision, so everything I said above about Netflix content applies to HDR10, too. Amazon is already streaming some of its original programming in the HDR10 format, and Sony recently launched its ULTRA 4K streaming service that uses the HDR10 format.

For disc lovers, all of the initial Ultra HD Blu-ray discs use the HDR10 standard, which the new Samsung UBD-K8500 player can play back on any HDR10-capable TV. Here's a list of all the Ultra HD Blu-ray titles currently available on Amazon.com.

How to Shop?
Just as every format war starts with confusion, every format war ends in one of two ways: One side wins (Blu-ray over HD DVD) or everyone learns how to peacefully co-exist (Dolby and DTS). The fact that TV manufacturers like LG, Philips, and VIZIO, as well as content providers like Netflix and Amazon, are already embracing both Dolby Vision and HDR10 means we might get lucky and skip more quickly to peaceful co-existence. If not? Then your safest bet right now is to buy a UHD TV that supports both formats.

One point worth highlighting is that, while Dolby Vision cannot be added to a TV via software update, HDR10 can--which is how VIZIO can add such support to its existing Dolby Vision TVs. So, if you have to choose sides, it might be safer to go with a Dolby Vision display, in the hope that HDR10 support could be added down the road.

On the surface, HDR10 appears to have more momentum right now. The format enjoys more industry support, and it requires no licensing fee. This year, you can choose from a lot of HDR10 TVs, offered at a wide range of prices, as well as HDR10-friendly Blu-ray devices and discs. However, you should never underestimate the influence and tenacity of Dolby, who plays a large role along all parts of the content chain, from production to distribution to playback. From my discussions within the industry, it seems that some experts prefer Dolby Vision precisely because it's a closed system that ensures more precision/reliability. But if we've learned anything from previous format wars, it's that the "better" technology doesn't always emerge victorious.

Additional Resources
• HDR (high dynamic range) on TVs explained, FlatPanelsHD.com
• Dolby's White Paper on Dolby Vision is available here.
• Visit SpectraCal's HDR page for more technical details, and check out this white paper
• The Color's the Thing That Will Make 4K So Amazing at HomeTheaterReview.com