INSUBCONTINENT EXCLUSIVE:
Image copyrightTimeline Television LtdImage caption
The BBC's trial was the first 4K HDR live broadcast of its kind
The BBC has broadcast a live event in 4K resolution and high dynamic range (HDR) colour for the first time.Its iPlayer service
streamed a full rugby match on Sunday, which was made available to the public but not promoted in advance.BT began screening live sport in
4K in 2015, and Sky followed a year later.But many experts believe HDR offers the more significant improvement of the two video technologies
for owners of all but the largest TVs."The trial met its objectives," said Phil Layton, BBC Research Development's head of broadcast and
connected systems."We have proved our workflows, but like all trials there are issues we need to investigate and correct for the future."HDR
takes advantage of the fact modern screens can go brighter and/or darker than they used to be able to, providing a greater dynamic range.As
a result, the shadows of an image can be made less murky while the highlights - including glints of light reflected off metal or water - can
This makes it possible to deliver a television image that gets closer to the dynamic range the human eye can handle, thus making the picture
seem more realistic.HDR is also accompanied by the adoption of a "wider colour space", meaning millions more colours can be displayed on
compatible screens than had been the case before.Image copyrightAppleImage caption
HDR uses the Rec 2020 colour space,
which is wider than the Rec 709 range of colours supported in most TV broadcasts
"We were very pleased when the Sun was able
to push through the clouds, allowing the HDR to really show its full potential and capabilities in both dynamic range and the Rec 2020
colour space," said Quinn Cowper, from Timeline Television, which was also involved in the BBC trial.By contrast, 4K - also known as
ultra-high definition (UHD) - refers to the fact that an image contains four times as many pixels as a 1080p high definition picture.This
allows more detail to be displayed, but unless the TV is large or its audience is sitting close by, it can be hard to tell the
difference."HDR is all about seeing the distance between the darkest blacks and whitest whites," said Joe Cox, from What Hi-Fi magazine."It
should make for a much more colourful and vibrant picture, which to anyone with a suitable TV is going to be that much more impressive than
4K alone."World Cup nextLast weekend's stream, of a rugby match involving the York City Knights and Catalans Dragons, followed a more
limited test earlier in the year.Image copyrightGetty ImagesImage caption
The BBC picked a low-profile rugby match to
trial its 4K HDR broadcast technology
In February, the BBC delivered a private livestream of 4K HDR footage from a FA Cup
football club's ground to TV manufacturers.A spokesman said that the broadcaster had taken deliberate decision not to publicise the
follow-up test - despite making it available to users of the iPlayer Beta app on compatible TVs - because the trial had been organised for
the benefit of its engineers rather than the public at large.He declined to reveal when the next experiment was planned, or if a fully
fledged service might be ready in time for the Fifa World Cup football competition, which begins on 14 June.HDR rivalsStreaming services,
including Netflix, Amazon and YouTube, already offer pre-recorded HDR TV programmes and films to UK viewers.But the BBC has teamed up with
Japan's NHK to create a new flavour of the technology, which they call hybrid-log gamma (HLG).Image caption
This
simulated image shows - on the right-hand side - the advantage of using high dynamic range for Blue Planet II
The two
broadcasters say HLG is better suited to live broadcasts than other types of HDR because it does not need to provide metadata - data about
other data - to work."The equipment just doesn't support it - and we know from where metadata is used elsewhere, it gets lost, it gets
corrupted," the BBC Research Development has previously said.HLG, however, has some theoretical downsides of its own.It is not capable of
describing as wide a dynamic range as Dolby Vision, nor can it provide information to calibrate the image to particular TV models
However, the BBC Research Development says its tests indicate people cannot notice the difference.The BBC is not, however, the first to
livestream sport in HDR.In March, BT claimed a "world first" when it streamed a Uefa Champions League game involving Juventus and Tottenham
Hotspur in the HDR 10 format.That trial, however, was limited to a 1080p resolution image rather than 4K.
