When is Dolby Vision Coming?
The quest for better movie quality at home
What is Dolby Vision?
Dolby Vision and HDR are the latest buzzwords in TV and movie marketing, and for once it may actually bring a genuine quality improvement to everyone looking to buy the next generation of UHD TVs.
There are many things that go into making a movie look good at home such as resolution, brightness, viewing angles, colour accuracy and refresh rate. Over the last few years we’ve seen very bright, very high resolution panels that you can view from any angle, but they still manage to look terrible! What’s going on?
The two most overlooked factors over the last few years of consumer TVs are colour accuracy and dynamic range. What does that mean?
What is Dynamic Range?
The dynamic range of an image is the range between the darkest part and the very brightest. For example, in a room with a windows, the difference between the shadowy cupboard and the bright sunlit stream.
In real life, the dynamic range of light is massive and the human eye is very sensitive to these changes.
Because most TVs over the last few years have concentrated on resolution and refresh rate at the expense of everything else, they do a pretty horrific
job of dynamic range.
An image showing the dynamic range in the real world
To understand why there are so many new standards at once, it’s probably important to note that quite a few technical developments have all occurred at once:
TVs are capable of much higher brightness than ever before
Data transfer and storage is much cheaper and easier than ever before
We have reached the practical limit for improvements in resolution
What are the problems with SDR?
Most current standards are actually designed around CRT TVs. CRTs were not capable of the high brightness of current TVs, and consumer requirements have changed dramatically.
To save encoding space and make hardware and broadcast cheaper, all video has typically been encoded with 8 bit technology (which allows for 256 gradations of each primary colour). This allows only a small range of brightness (A.K.A. low dynamic range). It also limits the range of colours available.
To make up for the fact that many displays are much brighter than CRTs ever were, many manufacturers “stretch” the brightness that is displayed, usually creating a washed out, inconsistent image.
The technology our current standards are based on
What is HDR-10?
HDR-10 is the first of the new standards to hit the market, and it seems that it will have very wide support. It is likely to be the baseline by which everything else is measured. It is supported by default on the new 4K Blu-Ray standard and Vudu, Netflix and Amazon already have some streams with this standard.
HDR-10 expands the peak brightness to 1000 nits, which is around what most modern LED displays are capable of. It also dramatically increases the colour space available, which should ensure significant increases in picture quality.
This is looking to be widely supported and, in my opinion, is a positive direction for the whole industry to be heading in.
How is Dolby Vision different?
For many years, Dolby have been a strong proponent of extending dynamic range of images, probably stemming from their strong interest in creating the displays and workflows used in high end movie colour grading and mastering. They have been among the first to create truly high dynamic range digital cinemas.
Dolby’s Lab’s initially tested to see what range of brightness viewers actually wanted to see, using a one of a kind monitor capable of crazy levels of brightness and colour accuracy.
They determined that normal people actually appreciate a very high level of dynamic range and that it would be very worthwhile creating a system capable of black levels down to 0.001 nits and brightness levels of up to 10,000 nits.
A Dolby Vision Cinema
This is far beyond what even the best professional monitors are capable of, but Dolby decided to base the standard on what future displays will be capable of to ensure this standard doesn’t have to change.
One of the very cool things about Dolby Vision is the plan to tailor the delivery of content based on the performance of the particular display (similar to the way HDMI lets devices broadcast their resolution capabilities). Dolby Vision uses dynamic metadata to determine your TV’s colour, brightness and contrast capabilities, delivering the appropriate part of the file to ensure the best possible quality for your particular display.
This means that Dolby Vision can create better picture quality on a very wide range of displays (even relatively entry level models).
Key Benefits…
12 bit Colour System (rather than 10 bit HDR-10)
Colour space, depth and dynamic range tailored to specific displays
Heavily marketed and likely to be well supported
Basically, Dolby Vision is one of very few heavily marketed terms of late to be a genuinely large step up in picture quality, making the most of current state-of-the-art display technology.
What about my existing 4K TV?
Unfortunately, many early 4K TV adopters are likely to be disappointed, as are many people who have purchased HDR capable displays.
Dolby Vision requires a very specific chipset, which your display probably doesn’t have yet, it also requires support for HDMI2.0a.
Many people who have spent several thousand on reference displays, will find the performance easily eclipsed with new material on some mid-level displays that support the Dolby Vision and HDR standards.
Your late model UHD TV may not support HDR fully
Note on OLED TVs
OLED TVs are likely to be a bit of an exception to the rule. Many will be certified for HDR without really hitting the peak brightness levels expected of LED LCD TVs. This is because OLED technology allows much better black levels, which allow a similar level of dynamic range, but are very expensive to make anywhere near as bright as the LCD equivalent.
What material is likely to be released?
35mm film has a very high dynamic range. Even older titles can be released using the HDR standards and have a genuinely superior image quality.
In addition, the majority of big budget pictures currently in production are using workflows that enable them to be easily released on 4K UHD Blu-Ray with Dolby Vision, HDR-10 or a couple of other competing standards.
This means we will see plenty of content released to make the most of these new formats. Netflix, Vudu and Amazon Instant are already dabbling in HDR and have released several titles in the HDR-10 format.
Many recently released fIlms will be released as UHD Blu-rays
What about the other HDR formats?
There are a few other competing formats for HDR. The two other well known standards are being developed by the partnership of BBC and NHK (for a broadcast friendly format) and by Technicolour and Phillips (for an easy to master format).
At this stage it looks like the standards shouldn’t be mutually exclusive Рthere is no reason why your TV or display can’t support all of the formats when they are fully developed.
Summary:
We’re really looking forward to what seems to be the first truly positive step forward in home cinema since Blu-ray was first introduced. Some of the fine details are yet to be sorted, but this seems to be very sensible and exciting technology. I personally cannot wait to see it in action.
Further Reading:
Home Theater Review also have a good simple summary of the state of HDR: Hometheaterreview.com
HDGuru have a more in depth technical explanation: HDGURU.com
Summary of the new SMPTE Standards: SMPTE.com
AVS Forum have a good summary of all HHDR Standards: AVSForum.com
Dolby Vision White Paper: Dolbylabs.com
Richard
