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standards

IN A NUTSHELL

]

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IEEE SIGNAL PROCESSING MAGAZINE [174] MARCH 2015

Profile was accepted as an option of video

codecs for Internet Protocol Television

(IPTV) applications by the International

Telecommunication Union–Telecommu-

nication Standardization Sector (ITU-T)

Focus Group on IPTV standardization [1].

The IEEE 1857 Working Group was

established in 2012 to work on IEEE

standards for advanced audio and video

coding, based on individual members of

the IEEE Standards Association from the

AVS Working Group. The IEEE 1857

Working Group meets three to four

times annually to discuss the standard

technologies, syntax, and so on. Until

now, the IEEE 1857 Working Group has

finished three parts of IEEE 1857 stan-

dards, including IEEE 1857-2013 for

video, IEEE 1857.2-2013 for audio, and

IEEE 1857.3-2013 for system [2].

AVS standards have been developed in

compliance with the AVS intellectual prop-

erty rights (IPR) policy. This policy

includes up-front commitment by partici-

pants to license essential patents with

declaration of default licensing terms—roy-

alty-free without compensation [(RAND-

RF) and otherwise under reasonable and

nondiscriminatory terms], or participation

in the AVS patent pool, or RAND. The dis-

closure of published patent applications

and granted patents is required, and the

existence of unpublished applications is

also required if the RAND option is taken.

The licensing terms are also considered in

the adoption of proposals for AVS stan-

dards when all technical factors are equal.

Reciprocity in licensing is required. The

protection of participants’s IPR is provided

to guard against the situation in which the

IPR of a participant are disclosed by

another party. AVS has encouraged the

establishment of a Patent Pool Administra-

tion (PPA) that is independent from the

AVS Working Group, which only focuses

on the standards. The AVS standards are

also fully compliant with the IPR policy of

IEEE standards.

Based on the success of AVS1 and the

recent research and standardization works,

AVS has been working on a new generation

of video coding technologies called AVS2

(or more specifically, Part 2 in the AVS2

series standards). In fact, since 2005 and

before the AVS2 project officially started,

AVS has been continuously working on an

AVS-X project to explore more efficient

coding techniques. AVS2 was started for-

mally by issuing a call for platforms in

March 2012. By October 2012, a reference

platform (RD 1.0) based on the AVS1 refer-

ence software was developed for AVS2 [3].

After that, AVS2 continued to improve its

coding efficiency, and the standard in com-

mittee draft 2.0 was finalized in June 2014.

It has been approved as a project of IEEE

standard, IEEE 1857.4, and a project of

Chinese national standard, both of which

are expected to be finished by the end of

2014 at the time of this writing.

As a successor of AVS1, AVS2 is designed

to improve coding efficiency for higher-res-

olution videos and provide efficient com-

pression solutions for various kinds of video

applications. Compared to the preceding

coding standards, AVS2 adopts smarter cod-

ing tools that are adapted to satisfy the new

requirements identified from emerging

applications. First, more flexible prediction

block partitions are used to further improve

prediction accuracy, e.g., square and non-

square partitions, which are more adaptive

to the image content especially in edge

areas. Related to the prediction structure,

transform block size is more flexible and

can be up to 64

# 64 pixels. After transfor-

mation, context adaptive arithmetic coding

is used for the entropy coding of the trans-

formed coefficients. A two-level coefficient

scan and coding method can encode the

coefficients of large blocks more efficiently.

Moreover, for low-delay communication

applications, e.g., video surveillance, video

conference, etc., where the background

usually does not often change, a back-

ground picture model-based coding

method is developed in AVS2.

The background picture constructed from

original pictures or decoded pictures is used

as a reference picture to improve prediction

efficiency. Test results show that this back-

ground picture-based prediction coding can

improve coding efficiency significantly. Fur-

thermore, the background picture can also

be used for object detection and tracking

for intelligent surveillance. In addition, to

support object tracking among multiple

cameras in surveillance applications, navi-

gation information such as those from the

global positioning system and BeiDou Navi-

gation Satellite System of China is also

defined, which mainly includes timing,

location, and movement information.

Finally, aiming at more intelligent surveil-

lance video coding, AVS2 also started a

[FIG1] The coding framework of an AVS2 encoder.

Intraprediction

Interprediction

Frame Buffer

Motion

Estimation

Loop Filter

Transform/

Quantization

Inv.Transform/

Dequantization

Entropy

Coding

–

AS A SUCCESSOR OF

AVS1, AVS2 IS DESIGNED

TO IMPROVE CODING

EFFICIENCY FOR HIGHER

RESOLUTION VIDEOS

AND PROVIDE EFFICIENT

COMPRESSION SOLUTIONS

FOR VARIOUS KINDS

OF VIDEO APPLICATIONS.

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THE WORLD’S NEWSSTAND