Overview of the High Efficiency Video Coding(HEVC) Standard之六

VI. HEVC标准的发展历程
History and Standardization Process
After the finalization of the H.264/MPEG-4 AVC High Profile in mid-2004, both ITU-T VCEG 
and ISO/IEC MPEG have been trying to identify when the next major advances in coding
efficiency would become ready for standardization. VCEG began studying potential advances 
in 2004, began identifying certain key technology areas (KTAs) for study in early 2005,
and developed a common KTA software codebase for this paper [14]. Various technologies 
were proposed and verified using the KTA software codebase, which was developed from
the H.264/MPEG-4 AVC reference software known as the joint model (JM).

TABLE VI
Structure of Coding Tools Associated With High Efficiency
and Low Complexity Configurations of HM 1
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From 2005 to 2008, MPEG began exploration activities toward significant coding efficiency 
improvements as well, organized several workshops, and issued a “call for evidence”
[15] of such advances in April 2009. Expert viewing tests were conducted to evaluate 
submissions of responses to the call. 


From their respective investigations, it was agreed that there were sufficient 
technologies with the potential to improve the coding efficiency significantly, 
compared to the existing video coding standards. The Joint Collaborative Team on Video
Coding (JCT-VC) was planned to be established by both groups in January 2010, and a 
joint call for proposals (CfP) on video compression technology [16] was issued by 
the same time to identify the initial technologies that would serve as a
basis of future standardization activities. 


At its first meeting in April 2010,  the JCT-VC established the HEVC project name, 
studied the proposals submitted in response to the CfP, and established the first 
version of a test model under consideration (TMuC) [17], which was produced collectively 
from elements of several promising proposals. A corresponding software codebase was 
implemented after this meeting. The technology submitted in several of the key proposal 
contributions  was previously discussed in a special section of the IEEE TRANSACTIONS 
ON CIRCUITS AND SYSTEMS FOR VIDEO TECHNOLOGY [18].


Although the TMuC showed significant coding efficiency improvements compared to prior 
standards, it had several redundant coding tools in each functional block of the video
compression system, primarily due to the fact that the TMuC was a collective design 
from various contributions. During the second JCT-VC meeting in July 2010, the process 
began of selecting the minimal necessary set of coding tools for each functional block 
by thoroughly testing each component of the TMuC.


Based on the reported results of the exhaustive component testing [20], an HEVC test 
model version 1 (HM 1) [21] and the corresponding HEVC working draft specification
version 1 (WD 1) [22] were produced as outputs of the third JCT-VC meeting in October 2010. 
Compared to the prior TMuC design, HM 1 was simplified greatly by removing coding tools 
that showed only marginal benefits relative to their computational complexity.


In several subsequent studies, the coding tools of the HM were classified into two 
categories called the high efficiency and low complexity configurations. Two corresponding 
test scenarios for verifying future contributions in the JCT-VC were also established. 
Table VI summarizes the HM 1 coding tools for the high efficiency and low complexity
configurations.


From the fourth to the eleventh JCT-VC meetings, not just coding efficiency improvements, 
but many other aspects including computational complexity reduction, unification of
various coding tools, and parallel friendly design were investigated, and the HEVC design 
was updated accordingly, until the current status of draft standard, as described in this
paper, was reached. In this context, it also turned out that the differentiation for 
low complexity and high efficiency was no longer necessary became possible to define 
the unified main profile. Table VII provides a summary of coding tools of the high 
efficiency configuration in HM 1 and the current specification of HEVC.


At the eighth JCT-VC meeting in February 2012, the draft version 6 of HEVC standard 
was produced, which was subsequentlyballoted as the ISO/IEC Committee Draft of the HEVC
standard. The tenth JCT-VC Meeting in July 2012 released the draft version 8 for a Draft 
International Standard ballot, and the finalized text for Consent in ITU-T and Final Draft
International Standard in ISO/IEC is expected to be produced in January 2013.


TABLE VII
Summary of Coding Tools of High Efficiency
Configuration in HM 1 and HEVC


Future extensions of HEVC, which are already being explored and prepared by the JCT-VC’s 
parent bodies, are likely to include extended-range formats with increased bit depth
and enhanced color component sampling, scalable coding, and 3-D/stereo/multi-view video 
coding (the latter including the encoding of depth maps for use with advanced 3-D displays).



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