High Efficiency Video Coding
Encyclopedia
High Efficiency Video Coding (HEVC) is a draft video compression standard, a successor to H.264/MPEG-4 AVC
H.264/MPEG-4 AVC
H.264/MPEG-4 Part 10 or AVC is a standard for video compression, and is currently one of the most commonly used formats for the recording, compression, and distribution of high definition video...

 (Advanced Video Coding), currently under joint development by the ISO
International Organization for Standardization
The International Organization for Standardization , widely known as ISO, is an international standard-setting body composed of representatives from various national standards organizations. Founded on February 23, 1947, the organization promulgates worldwide proprietary, industrial and commercial...

/IEC
International Electrotechnical Commission
The International Electrotechnical Commission is a non-profit, non-governmental international standards organization that prepares and publishes International Standards for all electrical, electronic and related technologies – collectively known as "electrotechnology"...

 Moving Picture Experts Group
Moving Picture Experts Group
The Moving Picture Experts Group is a working group of experts that was formed by ISO and IEC to set standards for audio and video compression and transmission. It was established in 1988 by the initiative of Hiroshi Yasuda and Leonardo Chiariglione, who has been from the beginning the Chairman...

 (MPEG) and ITU-T
ITU-T
The ITU Telecommunication Standardization Sector is one of the three sectors of the International Telecommunication Union ; it coordinates standards for telecommunications....

 Video Coding Experts Group (VCEG). MPEG and VCEG have established a Joint Collaborative Team on Video Coding (JCT-VC) to develop the HEVC standard. It has sometimes been referred to as "H.265", since it is considered the successor of H.264, although this name is not commonly used within the standardization project. In MPEG, it is also sometimes known as "MPEG-H". However, the primary name used within the standardization project is HEVC.

Background

HEVC aims to substantially improve coding efficiency compared to AVC High Profile, i.e. to reduce bitrate
Bitrate
In telecommunications and computing, bit rate is the number of bits that are conveyed or processed per unit of time....

 requirements by half with comparable image quality
Image Quality
Image quality is a characteristic of an image that measures the perceived image degradation . Imaging systems may introduce some amounts of distortion or artifacts in the signal, so the quality assessment is an important problem.-In photographic imaging:In digital or film-based photography, an...

, probably at the expense of increased computational complexity. Depending on the application requirements, HEVC should be able to trade off computational complexity, compression rate, robustness to errors and processing delay time.

HEVC is targeted at next-generation HDTV displays and content capture systems which feature progressive scan
Progressive scan
Progressive scanning is a way of displaying, storing, or transmitting moving images in which all the lines of each frame are drawn in sequence...

ned frame rate
Frame rate
Frame rate is the frequency at which an imaging device produces unique consecutive images called frames. The term applies equally well to computer graphics, video cameras, film cameras, and motion capture systems...

s and display resolution
Display resolution
The display resolution of a digital television or display device is the number of distinct pixels in each dimension that can be displayed. It can be an ambiguous term especially as the displayed resolution is controlled by all different factors in cathode ray tube , flat panel or projection...

s from QVGA (320x240) up to 1080p
1080p
1080p is the shorthand identification for a set of HDTV high-definition video modes that are characterized by 1080 horizontal lines of resolution and progressive scan, meaning the image is not interlaced as is the case with the 1080i display standard....

 and Ultra HDTV (7680x4320), as well as improved picture quality in terms of noise level, color gamut and dynamic range
Dynamic range
Dynamic range, abbreviated DR or DNR, is the ratio between the largest and smallest possible values of a changeable quantity, such as in sound and light. It is measured as a ratio, or as a base-10 or base-2 logarithmic value.-Dynamic range and human perception:The human senses of sight and...

.

Features

The HEVC draft design includes various coding tools, such as
  • Tree-structured prediction and residual difference block segmentation
  • Extended prediction block sizes (up to 64x64)
  • Large transform block sizes (up to 32x32)
  • Tile and slice picture segmentations for loss resilience and parallelism
  • Wavefront processing structure for decoder parallelism
  • Square and non-square transform block sizes
  • Integer inverse transforms
  • Directional intra prediction with a large number of prediction types (up to 35 per prediction block size)
  • Mode-dependent sine/cosine transform type switching
  • Adaptive motion vector predictor selection
  • Temporal motion vector prediction
  • Multi-frame motion compensation prediction
  • High-accuracy motion compensation interpolation (8 taps)
  • Increased bit depth precision
  • De-blocking filter
  • Adaptive loop filter (ALF)
  • Sample adaptive offset (SAO)
  • Entropy coding using one of two selectable types:
    • Context-adaptive binary arithmetic coding
      Context-adaptive binary arithmetic coding
      Context-adaptive binary arithmetic coding is a form of entropy encoding used in H.264/MPEG-4 AVC video encoding. It is a lossless compression technique. It is notable for providing much better compression than most other encoding algorithms used in video encoding, and is one of the primary...

       (CABAC)
    • Context-adaptive variable-length coding
      Context-adaptive variable-length coding
      Context-adaptive variable-length coding is a form of entropy coding used in H.264/MPEG-4 AVC video encoding. It is an inherently lossless compression technique, like almost all entropy-coders. In H.264/MPEG-4 AVC, it is used to encode residual, zig-zag order, blocks of transform coefficients. It...

       (CAVLC)


It has been speculated that these techniques are most beneficial with multi-pass encoding.

History

The ITU-T Video Coding Experts Group (VCEG) began significant study of technology advances that could enable creation of a new video compression standard (or substantial compression-oriented enhancements of the H.264/MPEG-4 AVC
H.264/MPEG-4 AVC
H.264/MPEG-4 Part 10 or AVC is a standard for video compression, and is currently one of the most commonly used formats for the recording, compression, and distribution of high definition video...

 standard) in about 2004. Various techniques for potential enhancement of the H.264/MPEG-4 AVC
H.264/MPEG-4 AVC
H.264/MPEG-4 Part 10 or AVC is a standard for video compression, and is currently one of the most commonly used formats for the recording, compression, and distribution of high definition video...

 standard were surveyed in October 2004. At the next meeting of VCEG, in January 2005, VCEG began designating certain topics as "Key Technical Areas" (KTA) for further investigation. A software codebase called the KTA codebase was established for evaluating such proposals in 2005. The KTA software was based on the Joint Model (JM) reference software that was developed by the MPEG & VCEG Joint Video Team for H.264/MPEG-4 AVC
H.264/MPEG-4 AVC
H.264/MPEG-4 Part 10 or AVC is a standard for video compression, and is currently one of the most commonly used formats for the recording, compression, and distribution of high definition video...

. Additional proposed technologies were integrated into the KTA software and tested in experiment evaluations over the next four years.

Two approaches for standardizing enhanced compression technology were considered: either creating a new standard or creating extensions of H.264/MPEG-4 AVC
H.264/MPEG-4 AVC
H.264/MPEG-4 Part 10 or AVC is a standard for video compression, and is currently one of the most commonly used formats for the recording, compression, and distribution of high definition video...

. The project had tentative names H.265 and H.NGVC (Next-generation Video Coding), and was a major part of the work of VCEG until its evolution into the HEVC joint project with MPEG in 2010. The "H.265" nickname was especially associated with the potential creation of a new standard.

The preliminary requirements for NGVC were bit rate reduction of 50% at the same subjective image quality comparing to H.264/MPEG-4 AVC High profile, with computational complexity ranging from 1/2 to 3 times that of the High profile. NGVC would be able to provide 25% bit rate reduction along with 50% reduction in complexity at the same perceived video quality as the High profile, or to provide greater bit rate reduction with somewhat higher complexity.

"H.265" was used as a nickname for an entirely new standard, as was the "High-performance Video Coding" work by the ISO
International Organization for Standardization
The International Organization for Standardization , widely known as ISO, is an international standard-setting body composed of representatives from various national standards organizations. Founded on February 23, 1947, the organization promulgates worldwide proprietary, industrial and commercial...

/IEC
International Electrotechnical Commission
The International Electrotechnical Commission is a non-profit, non-governmental international standards organization that prepares and publishes International Standards for all electrical, electronic and related technologies – collectively known as "electrotechnology"...

 Moving Picture Experts Group
Moving Picture Experts Group
The Moving Picture Experts Group is a working group of experts that was formed by ISO and IEC to set standards for audio and video compression and transmission. It was established in 1988 by the initiative of Hiroshi Yasuda and Leonardo Chiariglione, who has been from the beginning the Chairman...

 (MPEG). Although some agreements about the goals of the project had been reached by early 2009, e.g. computational efficiency and high compression performance, the state of technology at the time seemed not yet mature for creation of an entirely new "H.265" standard, as all contributions were essentially modifications closely based on the H.264/MPEG-4 AVC
H.264/MPEG-4 AVC
H.264/MPEG-4 Part 10 or AVC is a standard for video compression, and is currently one of the most commonly used formats for the recording, compression, and distribution of high definition video...

 design.

The ISO/IEC Moving Picture Experts Group
Moving Picture Experts Group
The Moving Picture Experts Group is a working group of experts that was formed by ISO and IEC to set standards for audio and video compression and transmission. It was established in 1988 by the initiative of Hiroshi Yasuda and Leonardo Chiariglione, who has been from the beginning the Chairman...

(MPEG) started a similar project in 2007, tentatively named High-performance Video Coding. Early evaluations were performed with modifications of the KTA reference software encoder developed by VCEG. By July 2009, experimental results showed average bit reduction of around 20% compared with AVC High Profile; these results prompted MPEG to initiate its standardization effort in collaboration with VCEG.

A formal joint Call for Proposals (CfP) on video compression technology was issued in January 2010 by VCEG and MPEG, and proposals were evaluated at the first meeting of the MPEG & VCEG Joint Collaborative Team on Video Coding (JCT-VC), which took place in April 2010. A total of 27 full proposals were submitted. Evaluations showed that some proposals could reach the same visual quality as AVC at only half the bit rate in many of the test cases, at the cost of 2x-10x increase in computational complexity; and some proposals achieved good subjective quality and bit rate results with lower computational complexity than the reference AVC High profile encodings. At that meeting, the name High Efficiency Video Coding (HEVC) was adopted for the joint project. Starting at that meeting, the JCT-VC integrated features of some of the best proposals into a single software codebase and a draft standard text specification, and performed further experiments to evaluate various proposed features.

Schedule

The timescale for completing the HEVC standard is as follows:
  • February 2012: Committee Draft (complete draft of standard)
  • July 2012: Draft International Standard
  • January 2013: Final Draft International Standard (ready to be ratified as a Standard)

External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
x
OK