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BT Sport Ultra HD: Details of 4K HDR trials emerge

While BT won’t be delivering any of its 4K content in HDR (High Dynamic Range) anytime soon, it’s not sitting on its hands. 

The tech giant is actively trialling technical solutions that could bring HDR to its nascent 4K Ultra HD TV platform with partners including Samsung and the BBC. 

At BT’s Innovation 2015 event, running from BT’s R&D hub in Ipswich this week, we got to see some of the early fruits of those trials up close – footage of the Americas Cup shot by BT in Portsmouth this year were being played back on two identical 4K TVs (Samsung JS95000’s), one with the standard dynamic range of contrast (the TV on the right) and another with HDR applied. 

For those who’ve not heard, HDR basically means a higher range of contrast is available on video content.

BT 4K HDR trial in action on Samsung JS95000's

Related: Behind the scenes at the British MotoGP with BT Sport, and When is 4K coming to Freeview? Demo of Ultra HD over DTTThis means that whiter and brighter areas of an image can look vivid and sharp without sacrificing the depth and richness of black areas of a panel. Without HDR, extremely dark or bright areas can look grey and washed out. 

Lighting conditions weren’t ideal at the stand, but hopefully you can appreciate the difference HDR makes from these images. You can see from the shots that on the left-hand panel, there’s greater definition of the clouds and waves.

Mile Nilsson, principal researcher at BT’s Adastral Park R&D centre also shed light on some of the progress made by the UK TV industry on helping to define broadcast standards for Ultra HD TV. 

Nilsson said: “What we’re showing here today is an approach that’s favoured by the BBC, and their focus is on compatibility between new services, the high dynamic range and the standard dynamic range. 

“The aim is to send one version of the content over the network, whether that’s DTT [i.e. Freeview, YouView etc] or over IP or whatever network [broadcasters] might be using and if you have a first generation UHD TV, then you’d get a good picture as you would do… but if you have one of the newer TVs that support HDR you’d get [a better picture].”

BT 4K HDR trial - Samsung UHD Evolution Kit

BT currently delivers its Ultra HD sports channel over a multicast network, using BT Infinity FTTC (Fibre to the Cabinet) connections to reach subscribers at home. 

There’s currently no broadcast standards for 4K TV over the airwaves, which is something else that’s being discussed by the DTG’s UK UHD Forum – a cross-industry body that’s looking at ironing out all off of this stuff. 

Nilsson explained that the current standard dynamic range of contrasts is a hangover from the days when we all used Cathode Ray TVs. Because LCD and LED panels can kick out higher levels of brightness, a new standard is needed to prevent super bright and dark areas from looking grey and washed out. 

While you can see there’s an obvious difference in contrast here, the HDR content had a weird sea-green pallor. Nilsson told us that the footage hadn’t been properly colour-graded – it had been put together in less than a week by an engineer (BT’s regular colour grader was on holiday) which explains the weird hues. 

BT 4K HDR Trial - Some footage had not been colour graded as yet.

We’re pretty sure he was telling truth, because no one’s going to want HDR if it makes Premier League football look like it was filmed through Instagram’s Perpetua filter. 

There’s no solid date for when HDR will land on BT’s Ultra HD sport channel. BT’s head of TV Delia Bushell estimates it could be a couple of years, while Jamie Hindhaugh, chief operating officer of BT Sport expects that we’ll see support for 5.1.4 audio arriving on BT TV before HDR. 

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