The BBC is undertaking a trial of 4K high dynamic range (HDR) video on its iPlayer streaming platform.
The test involves four minutes of footage from its Planet Earth II series, which the BBC suggests reveal more detail and present more vibrant colours than was possible before.
It is part of the broadcaster’s efforts to develop technologies that will make live broadcasts in the new formats possible, although a minority of TVs are currently able to display the footage.
“One of the clips is a frog on a leaf with lots of rain, and the reason this is so interesting is that the redness of the frog is a really deep Ferrari red that you would never get in broadcast television at the moment,” explained Phil Layton, head of broadcast and connected systems at BBC Research & Development. “We want to show that this is how the BBC could make ultra-high definition HDR material available to iPlayer. And we want to use this as a trigger to work with manufacturers to get their products updated so there’s a pathway there for future on-demand BBC content.”
As the trial went live, only Panasonic’s latest screens supported the test’s underlying hybrid log-gamma (HLG) technology.
The BBC will make the footage available via the different smart TV versions of its iPlayer app as soon as the relevant models support it, but it will be some time before it starts offering scheduled broadcasts in 4K and HDR.
Filming Planet Earth II provided the perfect opportunity to capture the BBC’s world-class documentary making in unprecedented quality. The BBC iPlayer test footage follows a jaguar emerging from the shadows to stalk prey and the mesmerising effects of rain dropping on tiny animals and their habitats, including a range of greens and a frog in a shade of red never before seen on a TV.
The experiment is an early but important step toward streaming high-quality Ultra HD programmes on BBC iPlayer in the future. Central to the trial is the inclusion of HLG, which the BBC sees as an integral part of future Ultra HD programming. Where Ultra HD improves image quality by increasing the number of pixels in a TV set, HLG takes this one step further by providing better quality pixels.
As a form of High Dynamic Range, HLG works by enabling images to be shown in extremely high contrast. This provides greater sharpness, extended detail in the shadows and dark areas of the picture, a wider range of colours, and more natural and brighter highlights and mirror-like reflections.
Dan Taylor-Watt, Head of BBC iPlayer, said: “The extra quality HLG brings to Ultra HD needs to be seen to be believed. It’s still early days for the technology but this experiment puts us in the best possible position once audience demand is there. This year we’ve brought live events like the Euros and Olympics to iPlayer, introduced new personalised features and now we’re giving people a glimpse of what the future may hold.”
The public Ultra HD and HLG test on BBC iPlayer allows the corporation to better understand how the technology affects existing infrastructure and workflows. It also allows the team to identify the various obstacles and challenges to streaming full length programmes.
HLG was developed by BBC R&D and Japanese broadcaster NHK to address the complex needs of TV broadcasters. It is also based on open standards to ensure all audiences can enjoy the best possible Ultra HD experience in the future. HLG was recently included in the International Telecommunication Union’s (ITU) HDR-TV standard.