|Here's a better than average primer on DV, with some new(to me) information highlighted. I've also read in various reports that Samsung may be involved in the development and potential licensing of HDR10+, which would place them in a different position than I thought. More on this later. Cooters|
Dolby Vision HDR: everything you need to know
Dolby has played a key role in the development of HDR for both commercial cinema and home theatre applications. From a home entertainment perspective, the company’s most important contribution has been the advanced form of HDR, known as Dolby Vision.
Dolby Vision has the potential to improve consumers’ viewing experience by constantly optimising the way their TVs deliver HDR pictures. It also gives content producers more control over how their HDR programming appears on TVs. And it's coming to smartphones and tablets, too.
Until CES 2017, it was widely assumed that Dolby Vision hardware (screens and Ultra HD Blu-ray players) needed to carry a dedicated chip. However, it is now possible to add Dolby Vision support via a firmware update to devices with sufficiently powerful processors.
The industry standard HDR10 format is free for manufacturers to use, but Dolby Vision requires the payment of a licence fee. So what’s so special about Dolby Vision that hardware brands and consumers would pay extra for it? Quite a bit, actually.
What is Dolby Vision?
The Sony KD-55A1 OLED TV will get a Dolby Vision upgrade soon
The most significant advantage of Dolby Vision HDR versus HDR10 is the addition of dynamic metadata to the core HDR image data.
This metadata carries scene-by-scene instructions that a Dolby Vision-capable display can use to make sure it portrays the content as accurately as possible. Dolby Vision-capable TVs combine the scene-by-scene information received from the source with an awareness of their own capabilities in terms of brightness, contrast and colour performance.
With HDR10 content, your HDR TV only receives static metadata; relatively basic ‘global’ information on the content being shown that applies to the entire film or TV show.
It can’t provide a display with updates on how each specific shot or scene should be shown. Nor does HDR10 carry the same facility for continually optimising the picture to the capabilities of the screen it’s showing on.
Dolby Vision is built on the same core as HDR10, which makes it relatively straightforward for content producers to create HDR10 and Dolby Vision masters together. This means that a Dolby Vision-enabled Ultra HD Blu-ray can also play back in HDR10 on TVs that only support that format.
Dolby Vision allows content producers to have either one or two ‘layers’ of data; one carrying just an HDR signal, the other carrying a standard dynamic range (SDR) signal. This single HDR/SDR workflow approach makes Dolby Vision a convenient tool for content creators and broadcasters to use.
Another advantage of Dolby Vision is that the metadata is embedded into the video signal, meaning it can run across ‘legacy’ HDR connections as far back as version 1.4b. Despite only using static metadata, HDR10 requires HDMI 2.0a compatibility.
On the content production side, Dolby Vision seems more focused on pushing HDR to its technical limits. The minimum specification for Dolby Vision mastering requires the use of reference monitors with a contrast ratio of 200,000:1, peak brightness of 1000 nits, colour range ‘approaching’ the Rec 2020 standard, and support for the SMPTE ST-2084 HDR format.
However, Dolby has also developed a reference ‘Pulsar’ monitor that provides an 800,000:1 contrast ratio, a peak brightness of 4000 nits, and the so-called P3 colour range used in digital cinema applications.
Given its greater creative palette, and the drive towards delivering consumer TVs with ever greater brightness ( Samsung’s 2017 TVs are claiming to hit 2000 nits), it’s certainly tempting to see this Dolby Pulsar monitor as a glimpse of HDR to come.
MORE: Sony KD-55A1 review
Will Dolby Vision deliver better pictures?
LG OLED55B7V is a five-star OLED TV with Dolby Vision
Our initial experience of Dolby Vision in the UK was limited to a few Netflix and Amazon streams, plus a handful of Dolby Vision film clips viewed on LG Dolby Vision TVs, and our impressions were that Dolby Vision makes a difference for the better.
In a head-to-head comparison of Dolby Vision and HDR10 demo clips, Dolby Vision images appear to contain more tone definition in bright areas; more balanced, nuanced and natural colours right across the spectrum; better contrast range management; and a greater sense of detail – presumably a side effect of the colour and light management improvements.
However, we've recently done a head-to-head comparison using the Despicable Me 4K Blu-ray disc, and the results were unexpected. The Dolby Vision effect came across looking rather flat and contrast was more subdued; it was surprisingly less vibrant and spectacular than the HDR10 version of the film.
There is a chance it could depend on the film and how Dolby Vision is implemented on the disc. We've just bought a copy of Power Rangers on 4K Blu-ray to see how live action compares. We'll be sure to report back with our findings asap.
We look forward to a more thorough review of the various HDR video options later on in the year when both the hardware and software markets are more mature.