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.
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 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.
Will Dolby Vision deliver better pictures?
Though our experience of Dolby Vision in the UK is limited to a few Netflix and Amazon streams, plus a handful of Dolby Vision film clips viewed on LG Dolby Vision TVs, initial impressions are Dolby Vision makes a difference for the better.
In a head-to-head comparison of Dolby Vision and HDR10, 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.
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.
More after the break
How can you watch Dolby Vision?
Loewe has announced that its debut OLED TV – due to launch soon – will support Dolby Vision, while the Oppo UDP-203 Ultra HD Blu-ray player is confirmed to be getting Dolby Vision support via a firmware update by April this year.
LG is also launching a Dolby Vision Ultra HD Blu-ray player this spring, and Sony has announced that Dolby Vision will be supported on its 2017 high-end TVs (including its A1 OLEDs) as well as being added retrospectively to 2016’s ZD9 LCD TV.
Dolby Vision is also available via the Google Chromecast Ultra, while in the US, Vizio, Hisense, LeEco, Philips (which has a different owner to Philips in Europe) and TCL all already have Dolby Vision TVs on sale or set for launch.
The US Philips brand has also unveiled a Dolby Vision Ultra HD Blu-ray player due to launch this year.
This may be down to their reluctance to add to manufacturing costs with the license fee, though Dolby Vision has been adopted by a number of budget TV manufacturers.
Both companies have stated that they trust their own TV processing, and the capability of their own hardware, arguing that it optimises HDR10 images efficiently enough without Dolby Vision.
But that doesn’t take into account Dolby Vision’s potential for content creators to have more say over how their content appears.
While Samsung and Panasonic have achieved some strikingly good, arguably class-leading HDR images from HDR10 sources, it would be interesting to compare Dolby Vision on a Samsung or Panasonic TV with their HDR10 performance.
And it’s worth noting that Samsung is currently proposing a new royalty-free dynamic metadata HDR system of its own…
What Dolby Vision content is available?
There are currently no Dolby Vision Ultra HD Blu-ray discs on the market. However, Lionsgate, Sony, Universal and Warners have all promised Dolby Vision UHD Blu-ray releases for 2017 – though no specific titles have yet been announced.
The upcoming PC game Mass Effect: Andromeda will support Dolby Vision, heralding a whole new gaming outlet.
Dolby Vision can also be applied in a live broadcast environment – though we’re not aware yet of any broadcaster announcing plans to use it. And for broadcasting HDR 4K programmes, another format, HLG, seems to be in prime position.
What's the future of Dolby Vision?
Dolby has gone out of its way to dismiss talk of any possible format war, positioning its technology as a ‘value added’ proposition in relation to HDR10, not a direct competitor.
Dolby Vision is essentially extra information applied on top of an HDR10 core, so it’s easy to ensure that all Dolby Vision content is also compatible with devices that only support HDR10.
It’s not mandatory for a content creator to deliver both HDR10 and Dolby Vision support though. US streaming platform VUDU did not initially support HDR10 alongside Dolby Vision, nor did Vizio’s first Dolby Vision TVs.
Both have now added HDR10 support, so there is currently no Dolby Vision platform that doesn’t support both. There's no doubt the current HDR landscape is a little rocky, especially when you throw HLG (the broadcast HDR TV format), and the recently announced Advanced HDR by Technicolor into the equation.
Unfortunately, there's a chance it could only get more confusing as the new formats and standards settle. But fear not - we'll be on hand to help you cut through the jargon.