In Broadcast - January 2016 - 37


37

www.inbroadcast.com | Vol: 6 - Issue 1 | January 2016

InMedia

HEVC: The Current Reality
By Bernard Riera, Director of
New Technologies and Innovation
Why a new video codec? If we
look at the evolution of video codecs
over the last two decades we find
that with each decade there's a new
video standard associated with a new
video codec. In 1993, MPEG-2 was
able to support the introduction of
the SD digital video standard; in 2003,
MPEG-4 was associated with HDTV.
Following this trend it's not surprising
that UDHTV needs a new video codec,
hence HEVC (High Efficiency Video
Codec), which is part of the "MPEG
family".
What does HEVC promise?
HEVC/H.265 is designed to replace
MPEG-4 AVC/H.264 with the objective
of halving the required bit-rate without
impacting on the perceived video
quality. Consequently, HEVC matches
perfectly with the need for bit-rate
optimisation with UHD; it must be
remembered that native UHD content
needs a bit-rate equal to four times
that required for the same content in
HD.
Another important point to highlight
is HEVC's ability to allow telcos and
OTT players to distribute HD content
over "narrowband" networks such
as mobile and DSL, consequently
reaching a larger audience.
What are the typical use cases
for HEVC? If you have a look at the
mass market, we can identify several
use-cases:
*	 IPTV services (live/on-demand),
videoconferencing and
online gaming;
over ADSL for HD TV and
over fibre for UHD TV;
*	 OTT services
(live/on-demand/HbbTV),
videoconference and
online gaming;
*	 Mobile services - unicast and
broadcast (eMBMS);
*	 Terrestrial broadcasting
(DVB-T/DVB-T2) and
satellite broadcasting
(DVB-S/ DVB-S2);
*	 Distribution to cinemas -
content including trailers
and advertising, live events
(sport, news and more).

For professional services, HEVC could
be used for:
*	 Audiovisual market;
*	 Live contribution (HD/UHD);
*	 File contribution (HD/UHD);
*	 Remote production and
post-production;
*	 Others markets, for example
telemedicine;
*	 Remote imaging.
What
are
the
technical
specificities of HEVC and how
does it interact with the existing
ecosystem? HEVC is a joint standard:
ITU-T/VCEG and ISO-IEC/MPEG. At the
transport and signalling level HEVC
can be considered to be similar to
MPEG4/H.264.
It means HEVC/H.265 is fully
compliant
with
the
existing
infrastructure and protocols used for
MPEG4/H.264, including DBV and
HTTP transport protocols such as
dynamic adaptive bit-rate techniques
like MPEG-DASH or HLS. As an
example, we can easily mix in the same
DVB multiplex channels encoded with
MPEG-4 codecs and channels using
HEVC. This represents a key advantage
for bouquet operators by managing
the transition smoothly from HD to
UHD. From a technical point of view,
we can roughly say that HEVC is an
optimisation of MPEG-4/H.264.
Does HEVC fulfil its promises?
Several objective and subjective tests
have been conducted over recent
years by both industry players and
R&D collaborative projects such as
4Ever (www.4Ever-project.com). The
HEVC processes images by adjusting the
size of the macro blocks, a key improvement
over H.264

results of these tests demonstrate
that HEVC matches the claims for both
HD and UHD content, including HD on
mobile devices.
As an example, the perceived
quality, based on a non-expert panel
of viewers, is what's achieved with
HD content encoded with HEVC at a
bit-rate of 8 Mbps is the same as that
achieved by H.265 at 3 Mbps.
The bit-rate optimisation versus
MPEG4-AVC is equal to 50% for any
type of content when using a bit-rate
equal to/or higher than 3 Mbps (high
bit-rate networks). For low bit-rate
networks (1 Mbps) the measured
improvement is between 25% and
50%, depending on the content.
Why should content providers
move to HEVC? We can split the massmarket delivery business into two main
categories - delivery over broadcast
networks and delivery over broadband
networks.
Delivery over broadcast networks
including DTT, DTH and IPTV, needs
the use of a set-top box or integrated
decoder.
The
main
economic
challenge is related to the need for
decoder renewal, as the existing
ones cannot be upgraded to support
HEVC. Nevertheless, considering the
lifecycle of STBs/IDTVs and the bitrate optimisation achieved by the
introduction of HEVC, there's no doubt
about the adoption of HEVC, it's just a
question of how quickly it happens.
Delivery over broadband networks
including mobile TV and web TV,
requires the use of a browser or
a dedicated app installed on the
connected device. As HEVC is fully
compliant with dynamic adaptive
streaming mechanisms, and as HEVC
players are compliant with HTML5,
there's no technical barrier to moving

quickly. In the short-term the OTT
market will be the main driver of UHD
content delivery through VoD offers:
we can expect very fast adoption of
HEVC for this market.
For the professional markets
including A/V and enterprise services,
the situation is easier than for legacy
broadcast delivery. Considering the
cost benefits, this opens up new uses
and markets as described previously
so there's little doubt about the rapid
adoption of HEVC.
What is the roadmap for HEVC
deployment? As of today the industry
is ready to supply the equipment
needed to set up an HEVC chain.
Software-based
non-real-time
transcoders and real-time encoders
for both HD and UHD standards are
available. This includes "cloud-ready"
versions (compatible with virtual
machines) for distribution over DTH,
DTT and OTT.
There have been announcements
made about HEVC set-top boxes by
both chipset manufacturers and STB
manufacturers; it means than the new
generation of STBs will include HEVC
decoders.
At the contribution level, UHD demos
using HEVC real-time encoders have
been carried out in 2015, an example
being during the 2015's French Open
Tennis where the 4Ever Project (see
above) demonstrated the ability to
feed a 4K/50 frames per-second live
transmission over satellite, which was
displayed at a large screen cinema.
Manufacturers have plans to deliver
hardware-based, ultra-low latency
encoders and associated professional
decoders (IRD) compatible with
contribution standards, including Main
12, Main 4.2.2 10 and Main 4.2.2 12
profiles.
http://www.inbroadcast.com http://www.4Ever-project.com https://youtu.be/5blSJiGlm8o
Table of Contents for the Digital Edition of In Broadcast - January 2016
