1) HEVC (High Efficiency Video Coding) is a new video compression standard that can provide 50% smaller file sizes than H.264 with similar or better visual quality.
2) It is being developed by MPEG and JCT-VC to replace existing video coding standards like H.264 and help meet the increasing demand for high resolution video.
3) Some benefits of HEVC include reduced bandwidth and storage requirements for streaming services, however it also has higher computational requirements and many devices still do not support playback.
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High Efficiency Video Coding
(HEVC) Standard
Dhruv Kanojia, Devesh Shyngle, Prakrit Sethi
Northern India Engineering College, Shastri Park, New Delhi-110053, India
kanojia24.10@gmail.com, devesh.shyngle@gmail.com, prakritsethi141195@gmail.com
Abstract—HEVC is a new generation codec
that is currently in use with changes and
improvements being made side by side. It was
created to provide data compression on a scale
where you can cut down the file size to nearly
half of its original size with almost no loss in
the visual quality. All this happens with the
same or lower video bitrate. Using HEVC, we
can save a lot of bandwidth and hard drive
spaces.
Keywords —Advanced video coding (AVC),
H.264, High Efficiency Video Coding
(HEVC), Joint Collaborative Team on Video
Coding (JCT-VC), Moving Picture Experts
Group (MPEG), MPEG-4, standards, Video
Coding Experts Group (VCEG), British
Broadcasting Company (BBC), Nippon Hōsō
Kyōkai (NHK)
I. INTRODUCTION
HEVC, which stands for High Efficiency
Video Codec or simply shortened to H.265 is
a new generation video codec. As the name
suggests, it’s a video codec that promises to
outperform the current generation options
like, H.264 or AVC (Audio Video Codec).
HEVC is being developed by
the ISO/IEC Moving Picture Experts
Group (MPEG) and it boasts about 50% file
size reduction as compared to any of the
predecessor video codec. It was developed by
JCT-VC, a joint venture between
the ISO/IEC MPEG and ITU-T[3]
. HEVC
differs from H.264 and yet it is similar to
H.264 codec. Both the codec compare the
video frame by frame and find the redundant
areas in all the frames[3]
. One of the basic
differences in HEVC is the expansions of the
pattern comparison, i.e., how the codec
searches and interprets the pixels of the
image. Since a video is nothing but a
compilation of images in various frames, the
codec takes it as an image, frame by frame
which composes a video. HEVC also
promises improved motion vector prediction,
which basically predicts the motion in an
image by comparing the consecutive frames.
II. PREVIOUS GENERATIONS
The most widely used codec today is "H.264"
and it is supported by almost every device.
H.264 differs significantly from its
predecessor "XVID" in many ways. Some of
them being the whole searching and basic
working structure of H.264. H.264 supports
wide variety of container formats
(extensions), ranging from the very old '.avi'
to latest '.mkv'. One can choose any container
format and the codec can be H.264, but
mostly people choose '.mkv' because it
supports various streams to be mux-ed
together.
H.264 had certain limitations like Encoding
and Decoding complexity, Error Resiliency
and H.264 seems to not work so well with
dark areas on lower bitrate or high motion
frames[1]
. It can perform very well with a
little higher Bitrates, which leads to resulting
into a bigger file size. While H.264 is a
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standard currently and is performing pretty
well, there is a need of a codec that can
overcome the problems of H.264 and do the
same or better work, while giving lesser file
sizes.
H.265 was developed with the aim to cut
down the size of the video, while keeping the
same or better video quality on the same
bitrate offered by H.264. One should always
remember that the video quality depends on
the source video. If the source video has
artifacts, the encoded video from any of the
codec would also have those artifacts, even
with the best settings.
H.265 has been successful in cutting down
the video size and provide a better quality so
far. And it has served its basic purpose.
However, H.265 have its own limitations
which are still being fixed and improved over
the time.
III. APPLICATIONS
Now that we have a video codec that can
reduce file sizes, where can we implement it
and how can it be used? There are/can be
many uses of HEVC that will definitely
change the way the internet works. If HEVC
becomes a video codec standard, we can
stream videos online without buffering or
very less buffering. Since HEVC cuts the file
size to about 50%, a 50 MB video file could
be easily sized down to 25MB, which will
significantly cut down the stream size and
buffer time. And while all this happens, the
quality of the video remains same. We can
save on tons of bandwidth and countries with
slow internet connection can definitely enjoy
better video services.
If video streaming services welcome H.265,
they can save their server bandwidth as well.
Streaming a 50 MB video to 100 people
simultaneously won't put much of a pressure
on the web servers, however, if we were to
consider a daily basis reality, a major video
streaming company delivers its content to
thousands of users simultaneously. And let us
not forget that these companies provide their
services in different parts of world as
well.When we consider this and look at it
practically, serving a 50 MB video to about a
thousand users would burn up at
approximately 50,000 MBs of data that
nearly adds up to be 50 GB.Streaming 50
GBs of data at once is a stressful condition
for a web server, and is also non profitable for
the concerned company.
However, if the companies were to take
H.265 into consideration, they'll have to
stream half the amount of data. This is still a
very big number but appears miniscule when
compared to the original amount. They can
stream the content to more audience with the
same server which would be cost effective
and also conserve their resources.
Shifting to HEVC could prove to be a win-
win situation for everyone.
Many companies have already started
working and adopting HEVC and are
planning on using it by the end of this year[4]
.
HEVC can be very promising in near future.
IV. LIMITATIONS
Like every coin has two sides, HEVC also
has some downsides to it. With all these
advantages, there ought to be certain
disadvantages. HEVC doesn't necessarily
have 'disadvantages', rather it should be
termed as 'limitations of implementing
HEVC'.
Some biggest problems that hold back HEVC
from becoming a video codec standard are:-
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More processing power required for
the video playback.
More Encoding time.
Cost of Implementation
Playing HEVC is something that all or most
of the devices cannot do. HEVC is still have
the 'under-development' label on it and it is
still not supported by most of the devices, if
not all. The primary reason for this is, that it
is a little too heavy for devices to handle and
requires more processing power to render the
video on the device. So, most of the handheld
devices cannot play x265 without lagging,
heating up or the worst case, crashing
themselves.
HEVC also takes a lot of time to encode a
video into H.265, which is one of the main
factor that shapes the usage of the codec. And
since HEVC is proprietary, whenever
someone encodes an HEVC video, they need
to pay to the authors of HEVC[5]
.
However, HEVC can prove to be a game
changer.
HEVC playback shouldn't be a huge hurdle
as well, because most of the devices
manufactured after the successful launch of
HEVC-II already have in-built HEVC
decoders. Even the handheld devices like an
Android phone can support HEVC playback.
V. IMPLEMENTATION
HEVC is currently under development and is
not yet recognized as the standard. Many
companies have patent to the technology and
have plans on implementing the HEVC in
near future on their platforms. Currently,
Netflix has welcomed and implemented the
technology in their Ultra High Definition 4K
streams (4096×2160 PX). Though, UHD is
not available for all the streams available on
Netflix, but it is happening. However, this
also have some drawbacks because of
HEVC's limitations. Devices capable of
streaming videos need to have in-built HEVC
decoder, or the user should be able to install
the decoder themselves, if it is not present.
So, any subscriber with a 2 year old TV set is
mostly likely to be not able to play the UHD
on it. It should be noted that most of the TV
sets and devices produced a year ago have
HEVC decoder in-built[6]
.
Companies like BBC and NHK are also
working on delivering HEVC streams to their
users soon[4]
. This will lead to clearer streams
with less or no buffering in the real-time
streaming.
A. ROYALITY ISSUES
As mentioned before, HEVC is a proprietary
technology and one need to pay to the
corresponding owner[5]
. This is not a subject
of concern, as this was the case when H.264
came in market. The main problem with
HEVC royalty is that there are multiple
patent holders for the technology. Many
companies have developed or are developing
their own version of HEVC to use. So, if one
needs to get a license to use HEVC, it is going
to be hard and a tedious task.
Previous technologies were also proprietary,
but they involved one group of patent
holder[5]
. This is clearly not the case with
HEVC and is something that can be a big
problem in near future when everybody
would want to implement the technology.
But, this haven't stopped the technology from
storming the market and attracting more and
more people towards it.
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VI. COMPARISION TABLE
TABLE I
DIFFERENCE BETWEEN H.264 &
H.265[2]
Category H.264 H.265
Compression
Model
Hybrid Spatial
Temporal
prediction
model
-Flexible
parition of
Macro Block
-Intra
prediction
-Introduced
multi-view
extension
- 9 directional
modes for intra
Entropy coding
is CABAC and
CAVLC
Enhanced hybrid
spatial temporal
prediction model
-Flexible
partitioning,
introduces codign
tree units
-35 directional
modes for intra
prediction
-Superior parallel
processing
architecture,
enhancements in
multi-view coding
extension
-Entropy coding is
only CABAC
Specification Supports Up to
4K
(4,096x2,304)
with upto 59.94
fps
21 profiles;17
levels
Upto 8K
UHDTV(8192x43
20) with up to 300
fps
3 approved
profiles;13 levels
Drawbacks Not suited for
UHD because
of high bit rate
requirements
Computationally
expensive(~300%)
due to larger
prediction units.
Key
improvement
- 40 - 50% bit
rate reduction
compared to
MPEG-2
-Lef the growth
of HD content
delivery for
Broadcast and
Online
- 40-50% bit rate
reduction at the
same visual quality
compared to H.264
-Potention to
realized
UDH,2K,4K for
broadcast and
online streaming.
Progression Successor to
MPEG-2 part
Successor to
MPEG-4
AVC,H.264s
VII. FUTURE SCOPE &
IMPROVEMENT
Every form technology has a scope for
improvement and H.265 is no exception. As
mentioned in the limitation of H.265, it is
resource heavy and is still not a standard
video codec. Slight changes can be
implemented in order to make it almost
perfect.
ACKNOWLEDGMENT
The Authors would like to thank the experts
at IEE Xplore, Google Scholar and the people
at Technophilia for providing us with the
opportunity to research on this topic. We
would also like to thank Mr. Jon Fingas, Mr.
Nitin Narang and Mr. Jan Ozer for their
Articles on HEVC.
REFRENCES
[1] Stack Overflow --
http://stackoverflow.com/a/4433645
[2] Media Entertainment Info --
http://www.mediaentertainmentinfo.co
m/2013/10/4-concept-series-what-is-
the-difference-between-hevc-h-265-
and-h-264-mpeg-4-avc.html
[3] IEEE Xplore --
http://ieeexplore.ieee.org/xpls/abs_all.js
p?arnumber=6316136
[4] EnGadget --
https://www.engadget.com/2013/05/09/
nhk-and-mitsubishi-develop-the-first-h-
265-encoder-for-8k-video/
[5] Streaming Media –
http://www.streamingmedia.com/Articl
es/Editorial/Featured-Articles/The-
Future-of-HEVC-Its-Coming-but-with-
Plenty-of-Questions-89010.aspx
[6] Insider Monkey –
http://www.insidermonkey.com/blog/ne
tflix-inc-nflx-4k-challenges-explained-
337400/