magazine - Connect-World

Ultra HD TV
is derived from a variety of ingest sources
as well as consisting of both national and
regional feeds. Lastly, even though the
highlighted workflow relates to Ultra HD,
television provision has to increasingly
cater for an ever expanding number of
multiscreen options.
It is likely that in the interest of time
broadcasters will provision their production
environment for Ultra HD in the same way
that most production facilities currently
do for HD. To cater for resolutions lower
than Ultra HD, transcoding the original
broadcast content in a cost-effective manner
is critical for broadcasters to maintain a
healthy margin. While this article discusses
the impact of Ultra HD and advocates
the use of HEVC, such a compression
scheme is equally applicable to the need for
compression efficiency in multiscreen all the
way up to OTT delivery. Many of
the challenges a broadcaster faces
when trying to establish an Ultra
HD channel are easier to solve in
a multiscreen environment. This
is because there is often little
legacy STB or PVR provision
associated with multiscreen.
Multiscreen playback relies on
software running on standard
platforms that can be quickly
repurposed for new compression
strategies like HEVC.
HEVC: Enabling Broadcasters to
Support Ultra HD
A major concern for broadcasters and
content providers is how to deliver
high-bandwidth services like Ultra HD,
specifically for catch-up TV. A new video
compression standard called High Efficiency
Video Coding (HEVC) provides the answer.
HEVC significantly improves upon the
current compression standard H.264 also
known as MPEG-4 AVC (Advanced Video
Coding) by reducing the data rate needed for
high-quality video coding by approximately
50 percent. This enables broadcasters to
deliver higher-quality services like Ultra HD
using the same amount of bandwidth. (See
Figures 2, 3, and 4.)
HEVC uses larger block sizes, enabling
more efficient coding of large images,
especially of regions with few changes
in the picture content. This is extremely
beneficial for applications like Ultra HD.
Improved Intra-frame prediction allows
better prediction of pixels by exploiting
redundancy within the current frame.
By offering more prediction directions
than AVC, HEVC allows for a more
sophisticated way of predicting and coding
the intra mode selected.
HEVC also addresses other issues, such as
banding, which won’t be discussed in great
detail in this article. However, it is important
to note that HEVC may include support
for multi-view video coding or stereo 3D
video in the future. This, combined with
scalable video coding, allows a video
stream, sequence, or image to be represented
in multiple ways and formats. In other
words, content can be prepared in different
resolutions, screen characteristics, frame
or bit rates, for viewing on multiscreen
devices, all while retaining a high level of
coding efficiency. With consumer demand
for multiscreen services rapidly increasing,
this will be important feature of HEVC.
Ultra HD and Multiscreen
While Ultra HD brings prestige to the
television screen, the real challenge is cost
effective delivery in multiple playout and
delivery scenarios, enabling increased
opportunities for targeted advertising.
The MPEG DASH standard will allow
content delivery operators to deliver
Internet services, including Ultra HD,
while containing the CAPEX and OPEX
associated with multiscreen delivery.
DASH provides operators with a universal
HTTP delivery format to cost-effectively
scale adaptive streams to any connected
device using a common encryption
technology with one master key. Utilizing
a single encryption standard, content is
encrypted once and streamed to clients
that support various digital rights
management (DRM) systems. Each client
receives a set of decryption keys and
other necessary information using its
specific DRM system, which is signaled
in the DASH protocol, and then has
the capability to stream the commonly
encrypted content from the same server.
DASH can be implemented across all
content delivery vehicles – broadcast,
mobile, interactive television, and the
Internet – while providing interoperability
between all DASH profiles and connected
devices. As Ultra HD content makes its way
onto multiple consumer devices, DASH will
be a critical enabling technology.
Applications and Consumer Adoption
HD took nearly a decade to mature;
therefore, Ultra HD will likely be a gradual
process before becoming a worldwide
broadcast format. When HD was first
introduced, there was relatively little
content. A lot of content was upconverted
from SD. A move to Ultra HD requires an
even greater stretch to allow HD
content to be repurposed.
It’s expected that Ultra HD will
first take off in the production
environment for applications
like sports, where there’s a huge
drive to achieve higher quality
for major events like the World
Cup. Ultra HD allows the use of
advanced slow-motion and pan
and scan techniques to capture
high-quality live and replay
content, which will greatly
enhance sporting event coverage.
Ultra HD also has massive appeal in the
download market, where industry giants like
Netflix and YouTube are already encoding
their files using HEVC to support Ultra HD
for cinematic 4K releases.
Before Ultra HD achieves mass adoption,
work needs to be done on the consumer
front. Current HDMI interfaces only support
resolutions up to 1080p at 50Hz and 60Hz.
Without a further iteration of the HDMI
standard any move toward Ultra HD will
be temporally hindered, unless the user is
prepared to use dual synchronized HDMI
connection into televisions. This approach is
unlikely to appear on consumer equipment,
although it is interesting to note that this
approach has been adopted on 4K cameras
where four HDMI synchronized connections
are used to sustain the bandwidth required
for baseband 4K video.
HDMI does have competition, namely
HDBaseT, an Ethernet-based standard using
Cat 5e connectors with major manufacturer
backing from the likes of Sony, Samsung,
44 • EMEA 2013