What is HDR? The latest TV and cinema tech explained

High dynamic range video is the biggest thing to happen to movies and TV since the switch to HD, but what is HDR?

But HDR, or high dynamic range, is something you definitely should care about as it's arguably going to offer the biggest visual change since the move from standard definition to HD video.

HDR content and compatible devices are increasing in number. LG unveiled its first HDR-compatible TVs at the IFA show this year, to match up with the existing Samsung HDR panels, and Amazon Prime Instant Video has started to stream actual HDR content to the wider world. And you can bet that the Vegas-bound Consumer Electronics Show (CES) will be shot through with HDR offerings like Brighton through rock.

With Netflix soon to join the HDR party and Ultra HD Blu-ray offering HDR support for the new optical disc format too, we'll soon have multiple devices to display the burgeoning high dynamic range content offerings.

Now the chickens and the eggs are finally coming together then it's time to get serious about this advanced new visual standard.

What is it?

At its most basic HDR is a method of getting greater variance in contrast and colour into moving images. That means having a wider range of colours, which also involves having greater levels of contrast.

It's been seen most in still photography up until now, where multiple exposure settings are used to take separate pictures and are then combined into one stunning image. That means getting more detail into both the brightest and the darkest elements of a picture.

It's essentially the same idea for the ol' moving pictures too. Inevitably though it has to be a more sophisticated setup to capture many more images every second. High dynamic range video then is shot with an overall expanded colour range, which means a HDR source won't just be about blacker blacks and brighter whites, but also about far greater colour definition too.

The idea is to bring video fidelity more in line with what the human eye actually sees.

It's simple to see what that means when you're sat inside looking out of a window during the day. Put your phone into camera mode and point it at the glass and you'll see the daylight world outside in a fair amount of detail but everything around it will appear far darker. Shift the focal point to somewhere inside the room, but with the window still in frame, and the outside world will likely become a blown-out, glaring bright spot as the darker room gains detail.

This is something your eyes don't do as they can capture a wider range of colour - and something HDR cameras don't do either.

"This allows [filmmakers] to deliver content with brighter highlights, we can make things more natural, more life-like. Things like reflections, halation of light, specular highlights, glint off a car, things that we see day-to-day," explained Stuart Bowling, Dolby's Director of Content and Creative Relations as we checked out the stunning Dolby Vision HDR cinema system.

As we're gaining more actual detail in the resolution of images it makes sense for them to become more detailed in their colour and contrast too. It this expansion that will make Ultra HD visuals seem more natural, less artificial, but also more vibrant too.

"HDR ensures you're seeing extremely accurate colours that have a higher range," said Netflix's Noesjka van der Helm about the upcoming streaming standard. "So instead of a ray of sunlight appearing washed out and white, you're able to notice the orange and yellow hues instead. It gives a much more exciting viewer experience with more colours, brighter highlights, better contrast and shadow detail."

Where can I watch HDR video?

Well, therein lies the rub. As 4K content is pretty thin on the ground it's worse still in terms of high dynamic range video.

The main sticking point is the need to have HDR used right from the start of filming if you want to get true HDR. But Dolby and IMAX have been working to get the film industry at large engaged with the new format and the new camera/projection technology for the cinema experience.

"At Dolby we're spending a lot of time with the major filmmakers," says Stuart Bowling. "Certainly, unanimously, every filmmaker we're working with is completely blown away and in love with what they can actually do now."

But HDR cinemas are still pretty rare right now. The nearest Dolby Vision cinema to us is in Hilversum in the Netherlands.

In the home though things are picking up speed.

Both Amazon and Netflix are in the process of integrating HDR into their streamed outputs, with Amazon recently opening up its Prime Instant Video service to offer HDR at no extra cost to its subscribers. There is only a single series of the Amazon original, Mozart in the Jungle, and the pilot for Red Oaks available right now, but more will be coming.

"HDR provides a truly stunning visual experience and we're excited that our original series, Mozart in the Jungle and the pilot episode of Red Oaks are the first titles to be made available in the unmatched picture quality," said Jay Marine, Vice President Amazon Instant Video EU.

Netflix is also in the process of getting HDR into its stream too.

"With 4K screens we have the resolution we need. Now it is about getting better pixels, not more pixels, to give viewers a much more exciting TV viewing experience,” explained Netflix's van der Helm. “Put simply, HDR is a way to bring greater definition and variation of colour to images."

Some of Netflix's original series are already being filmed with HDR in mind - such as the cinematic Marco Polo - so when it does turn the tap on for its HDR stream there will be content ready to roll.

But there will also be ways for HDR to be 'back-rendered' into existing video too.

Technicolor is working on an open standard that will upscale standard range (SDR) video to increase the colour and contrast depth. The new system allows real-time access to the colour information in a video, giving content providers the means to directly control the highlights, lowlights and mid-tones of a moving image.

If that process takes off - and is able to give a close approximation of the intensity of a true HDR source - then the problem of a dearth of HDR content could be a rapidly solved issue.

Combine that with the upcoming Ultra HD Blu-ray optical disc standard, with its HDR support, and we'll soon have all the classics remastered in UHD 4K as well as back-rendered into high dynamic range too.

Not sure how well that's going to work for Citizen Kane, but 2001: A Space Odyssey might just become an even more transformative experience...

What do I need to watch HDR?

Sadly you're going to need a new TV.

Well, some of you are anyways. If you're one of the lucky few to have Samsung's latest JS9500 or JS9000 series of TVs then you're already primed for high dynamic range content - and have likely been champing at the bit to actually get hold of some to make your expensive tele shine.

There are also some Sony TVs which will get a HDR update via firmware later on this year.

But for the rest of us it's a case of getting hold of a brand new, HDR compatible set. Something to keep in mind if you're in the market for a new high-end TV right now.

With the IFA show barely a week away now we'll likely see a slew of new televisual announcements regarding HDR.

LG has already announced its new range of HDR-ready 4K OLED panels (the LG 65EF9500, LG 55EF9500 and LG 55EG9200) which will be available within weeks. Putting HDR with the advanced colour and contrast performance of OLED makes complete sense and could just put LG ahead of Samsung in the top-TV battle.

So, whether we're talking about the big-screen or home cinema experience, high dynamic range movies and TV shows are what we're going to be talking about from now on.

Ultra HD is so last year...

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