TELE-audiovision - Weltweit größte Digital TV Fachzeitschrift - page 164

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TELE-audiovision International — The World‘s Largest Digital TV Trade Magazine
— 09-10/2013
FEATURE
Ultra High Definition Television
We all are familair with High Defini-
tion Television. HDTV uses picture reso-
lutions of either 720p, 1080i or 1080p.
The first two are used for broadcasting
TV via satellites while the last one is
mostly used with Blu-ray discs. A HDTV
video signal has either 50 or 60 picture
frames per second. If a complete picture
is sent in every frame, the letter “p” is
added after the resolution figure (720p
or 1080p). If only half the horizontal
lines are sent in one frame (only odd
number lines, then only even number
lines and so on), the letter “i” depicts
such interlaced video.
Most of the contemporary satellite
TV receivers upscale any 720p or 1080i
video signals to 1080p and then output
the video to your living room TV. Now,
if we focus on the best version of HDTV
– 1080p – it has a picture resolution of
1920 x 1080. The new 4K UHDTV stand-
ard has doubled the resolution in both
axes to 3840 × 2160 while the 8K UHDTV
has even quadrupled it: 7680 × 4320.
The best way to realize how big an im-
provement UHDTV introduces is to look
at our simple picture showing TV screens
for different standards but the same pix-
el size (see picture). Imagine this: 4K is
like arranging 4 HD TV-sets in a 2x2 ar-
ray, while for 8K UHDTV one would need
8 HD TVs arranged in a 4x4 array!
Though resolution is the most obvi-
ous improvement over classical HDTV
it is by no means the only parameter
that has been changed. The other two
related to video are: color space and
frame rate. UHDTV has a wider color
space than HDTV. In particular, UHDTV
picture is able to reproduce more deeply
red and more deeply green colors which
can not be shown by our existing HDTV
equipment. In this way, UHDTV is able
to reproduce more natural colors.
The standard extends the allowable
frame rates up to 120 frames per second.
In this way 3D video can be reproduced
with up to 60 fps for each eye. 60 fps are
typical for North American TV whilst 50
Is it even a
standard?
Jacek Pawlowski
What‘s behind the
new standard?
Comparison of the TV screens for different resolution standards.
fps is used in most other areas including
Europe. Therefore European 3D TV will
use 100 fps rather than 120 fps.
Adding to these enormous improve-
ments in video performance, UHDTV
also expanded the audio quality. With
the new UHDTV standard an astounding
22 audio channels plus 2 low frequency
effects channels are possible. The 22
channels are divided into three groups:
an upper layer of nine channels, a middle
layer of ten channels and a lower layer
of three channels. Such complex audio
setups can be found at movie theatres
and thus with UHDTV this also becomes
available to the average viewer.
Of course, the first thing in order to
enjoy that big resolution is a UHDTV
compliant TV monitor. The best TV
manufacturers already offer 4K UHDTV
TV-sets with large screen (70” or more).
Monitors capable of showing 8K can be
seen at the professional broadcasting
exhibitions but sofar we know of no such
monitor available at regular stores.
Now, what about the sources of ul-
tra HD video? Presently, the choice is
extremely small. One model of UHDTV
video player has been announced with
a few pre-stored movies in 4K format
on the internal HDD. Blu-ray Disc As-
sociation have just started their work
on extending Blu-Ray Disc specification
to include 4K Ultra HD video. Similarly,
Sony announced that their PlayStation
4 will support 4K resolution but only for
photos and videos – not for the games
themselves.
And what is going on in the satel-
lite industry? In Europe EUTELSAT has
started 4K UHD test transmissions cod-
ed with the MPEG-4 codec on EUTELSAT
10A. Quite recently, SES has done one
step further and started a 4K channel
coded with the newest HEVC (H.265) co-
dec that helped reducing the necessary
bitrate down to 20 Mbit/sec.
You do not have to be an expert to
realize that 4K UHDTV requires 4 times
more bits than HDTV and 8K UHDTVre-
quires 16 times more bits. This is really
a problem because the communication
networks have finite throughput rates.
HEVC, known also as H.265, can help
here as its efficiency is roughly 2 times
better than MPEG 4. But even using
the best available codec you still need
about 20 Mbit/sec for 4K UHDTV and
as much as 80 Mbits/sec to broadcast
a single channel. And all this for 50/60
fps. If you liked to double the frame rate
to 100/120 to transmit 3D UHDTV you
would need twice the bandwidth.
It is funny to think that if in the future
8K is introduced to satellite broadcast,
one transponder will be carrying a maxi-
mum one channel – like in the old days
of analog TV.
The list of devices and standards that
still have to be developed or extended is
long: UHDTV cameras and other studio
equipment, HDMI interface, audio equip-
ment, and, of course, all kinds of digital
TV receivers: satellite, cable, IPTV and
(maybe) terrestrial. New equipment will
require new chip-sets and perhaps even
new hardware architecture to do the job
efficiently.
UHDTV is not backward compatible
with HDTV. In other words, your pre-
sent HDTV receiver will not process a
UHDTV channel. Naturally, in the begin-
ning, there will be a scarcity of ultra high
resolution programs and many UHDTV
channels will be created by up-scaling
regular HDTV. We can still remember
the first years of HDTV or more recently
3D HDTV – the same will happen with
UHDTV.
However, despite all the technology,
communication and media problems
linked with UHDTV, we strongly believe
that the race has started for good and
sooner or later we will all enjoy the won-
derful ultra high definition pictures in
our houses.
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