
Television
is evolving. 4K Ultra High Definition is rewriting the rulebook when it
comes to image quality, and in the process is beginning to
fundamentally change everything from programme production to
distribution technology.
4K capable TV sets are now available from
most of the major TV manufacturers, but they're merely the tip of a
very cool technology iceberg. So what, we hear you ask, is 4K really all
about?
Read on for greater clarity…
What is 4K?
YouTube : http://www.youtube.com/watch?v=OiOEgz2eG_cThe
headline fact is simple and dramatic: 4K Ultra HD TVs (also known as
UHD TVs) deliver four times the picture resolution of 1080p Full HD,
that's eight million pixels compared to two million pixels.
What
that means in terms of potential image clarity is more fine detail,
greater texture and an almost photographic emulsion of smoothness.
But
this is just for starters. Prior to a roll-out of TV services,
broadcasters are working out what else they can upgrade under the 4K
banner. In the UK, a working group chaired by the BBC and BSkyB are
mulling over every possible tweak, from higher frame rates to greater
contrast and a wider colour spectrum.
Talk to the engineers
steering this 4K broadcast bandwagon and they'll tell you everything
spec-wise is up for grabs. If this indicates to you that the 4K standard
is anything but set in stone, you'd be correct.
Ultra HD is going
to be a work in progress for years to come, but that doesn't mean you
should wait for the dust to settle before improving your image.
Difference between Ultra HD and 4K
4K
Ultra High Definition is actually a derivation of the 4K digital cinema
standard. However while your local multiplex shows images in native
4096 x 2160 resolution, this new consumer format is 3840 X 2160.
This
is one reason why some brands prefer not to use the 4K label at all,
sticking with Ultra HD instead. However, the numerical shorthand looks
likely to stick. As a broad brush label it's so much snappier!
Why should I care about 4K Ultra HD?
There
are many reasons why 4K should make you rethink your next TV purchase
(actually, there are eleven and you can read about them here), not all
of them immediately obvious.
Photographers who routinely view
their work on an HD TV are seeing but a fraction of the detail inherent
in their pictures when they view them at 2160p. A 4K display reveals so
much more nuance and detail – the difference can be astonishing. While
3D has proved to be a faddish diversion, 4K comes without caveats. Its
higher resolution images are simply better.
The higher pixel
density of a 4K panel also enable you get much closer without the
grid-like structure of the image itself becoming visible –this means you
can comfortably watch a much larger screen from the same seating
position as your current Full HD panel. Currently all available 4K Ultra
HD TVs are in excess of 50-inches.
Projectors
While
4K UHD TVs are on the fast track, the same can't be said for video
projectors. Only Sony offers 4K models, the high-end quasi pro
VPL-VW1100ES and the home cinema friendly VPL-VW500ES.
Currently
there's no consumer 4K solution for LCD, D-ILA or DLP projectors,
although that's likely to change in 2015, when Texas Instruments is
expected to begin shipping its first 4K DLP chipset for home hardware.
How expensive is an Ultra HD TV?
The
first wave of 4K TVs were large, really large. Both Sony and LG
launched with 84-inch panels, the KD-84X9005 and 84LM960V respectively.
Consequently,
they were saddled with price tags in excess of £20,000/$30,000. Not to
be outdone, Samsung weighed in with the 85-inch S9 at £35,000/$55,000,
clearly aimed at footballers and oligarchs!
However, prices have
fallen dramatically as screen sizes have shrunk and brands have
predictably embarked on a tit for tat price war.
So how small will 4K Ultra HD screens get?
In
the short term, screen sizes are likely to stabilise at 55-inches and
upwards. That's because as the screen size shrinks the advantage of
having such a pixel dense display starts to diminish. There's also an
irrefutable relationship between screen resolution and viewing
distances.
While seating will vary from home to home, generally
speaking a large 4K TV will provide an upgrade for a smaller 1080p
screen. However, the 4K resolution will ultimately be about more than
just definition.
High frame rate UHD broadcasting could have an
even greater impact than resolution when services begin – and the
benefits of HFR are not restricted to larger screen sizes. When this
second generation 4K UHD breaks cover, expect high-frame rate 4K TVs to
drop further down the size scale.
How far should I sit from a 4K TV for the best picture?
4K
Ultra HD is a much more intimate viewing experience than Full HD. In
many respects, the best way to view 4K is analogous to the way we view
films in a cinema. Old style cinemas were shoe-box shaped and most
patrons sat typically 3-5 screen heights away, because that was the most
comfortable viewing distance.
Contemporary cinemas are wider, and
now the optimum viewing distance is 1.5 screen heights back. From this
vantage point you can take in all the visual information that's
available and comfortably fill your field of vision. Translated to the
home, that makes the most comfortable distance to view a 65-inch 4K
screen approx. 1.5m. Of course, in many homes that simply isn't
practicl. Consequently, a large 4K screen is probably best viewed at a
distance of between 2-3m; time to rearrange your furniture?
What 4K content is available for me to watch?
Of
course the thorny subject confronting any 4K TV buyer today is:
"Where's the native content?" The answer, at least in the short term, is
that there isn't much of anything.
YouTube offers a nascent 4K
channel, but you'll require a powerful PC with a 4K capable graphics
card, of which there are few that make economic sense.
But the
lack of native 4K isn't quite the big deal you might at first imagine.
The truth is today's Ultra HD screens do such a remarkable job with
1080p content that you almost certainly won't feel shortchanged. Rather
than just linearly scale, big brand sets utilize all manner of database
interpolation to upscale images, and the results are spectacular.
To
take advantage of this, Sony has released a selection of Mastered in 4K
branded Blu-rays. These are in fact standard 1080p Blu-ray discs,
albeit ones based on the best available transfers which take full
advantage of available disc capacity. They have also been mastered with a
wider colour range than standard Blu-ray platters.
A 2160p
upgrade on the Blu-ray standard is inevitable, of course, which will
allow for true Ultra High Definition movies to be sold on disc. In
addition, Netflix appears to be making good progress with its 4K
streaming plans, expected to reach some sort of fruition in 2014.
Sony
meanwhile has rolled out a download service in the USA for owners of
Sony 4K TVs – however there's no sign of that arriving in Europe just
yet.
That said, native 4K broadcasting remains the ultimate goal.
BSkyB is just one of many global service providers who have been
successfully trialing acquisition and broadcast, as it mulls over the
financial potential of a dedicated 4K sports and movie channel offering.
Before
that can happen, transmission standards need to be agreed and chipsets
made available for a new generation of Sky+ UHD boxes.
When it
comes to 4K compression codecs, HEVC (High Efficiency Video Coding) is
the most widely talked about, however there are other options. Both Sony
and Netflix have partnered with Californian outfit Eye IO for their
online 4K services.
How important is HDMI 2.0 to 4K Ultra HD?
HDMI
2.0 is the latest iteration of the HDMI specification. While the
existing HDMI 1.4 standard can deliver 4K video, it's limited to 30
frames per second (or 30Hz). While this is fine for most movies,
broadcasters are looking for higher frame rates for TV.
HDMI 2.0
increases bandwidth up to 18Gbps and supports 4K Ultra HD at 50/60 fps,
with 12-bit 4:2:2 colour (you don't need any special cables for HDMI 2.0
interconnectivity, any current high-speed cable will work). However,
only Panasonic currently offers an HDMI 2.0 compatible 4K TV, in the
shape of the TX-L65WT600.
So where does that leave the remaining
first generation 4K sets? Well both Philips and Samsung, whose 4K panels
are coupled to separate connection boxes, say they'll simply introduce
new tuners which owners can upgrade to.
Sony and others are
looking to implement a firmware fix; by shedding colour sub pixels they
reckon they'll be able to fit high frame-rate 4K down a HDMI 1.4 pipe,
most likely with 8 bit 4:2:0 colour. How visible this kludge will be
remains to be seen. For what it's worth, we've seen JVC's 4K e-Shift3
projectors running 4K at the same colour resolution, and they look
spectacular so the omens are good.
Hang on, what about 8K?
If
4K offers four times the resolution of Full HD, then 8K will deliver 16
times the definition. 8K screens comprise a staggering 33 million
pixels.
This is an order of magnitude beyond any display
technology currently available, and only one broadcaster, Japanese state
owned NHK, has publically said it intends to commercialise the
technology.
Also known as Super Hi-Vision, a number of 8K trials
have been conducted, including acquisition at the London 2012 Olympics.
NHK has since pledged to shoot and transmit the 2020 Tokyo Olympics in
the format.
Of course, bringing 8K to market is a formidable
technical challenge. As with 4K, HEVC, is currently favoured as the best
compression technology for the job.
However, because the benefits
of 8K image definition only really become apparent on screens 84-inches
and larger, the format is not seen as a commercially viable platform by
most broadcasters and TV manufacturers. If you're waiting to jump from
Full HD to 8K, you could be kicking your heels for quite some time.
Choose a 4K TV
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