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The Video Coding Experts Group or Visual Coding Experts Group (VCEG) is the informal name of Question 6 (Visual coding) of Working Party 3 (Media coding) of Study Group 16 (Multimedia coding, systems and applications) of the ITU-T. Its abbreviated title is ITU-T Q.6/SG 16. It is responsible for standardization of the "H.26x" line of video coding standards, the "T.8xx" line of image coding standards, and related technologies.

The goal of Question 6 is to produce Recommendations (international standards) for video coding and image coding methods appropriate for conversational (e.g. videoconferencing and video telephony) and non-conversational (e.g., streaming, broadcast, file download, media storage/playback, or digital cinema) audio/visual services. This Question focuses on the maintenance and extension of existing video coding Recommendations, and laying the ground for new Recommendations using advanced techniques to significantly improve the trade-offs between bit rate, quality, delay, and algorithm complexity. Video coding standards will be developed with sufficient flexibility to accommodate a diverse number of transport types (Internet, LAN, Mobile, ISDN, GSTN, H.222.0, NGN, etc.).

Question 6 is part of Study Group 16, which is responsible for studies relating to multimedia service capabilities, and application capabilities (including those supported for NGN). This encompasses multimedia terminals, systems (e.g., network signal processing equipment, multipoint conference units, gateways, gatekeepers, modems, and facsimile), protocols and signal processing (media coding).


VCEG was preceded in the ITU-T (which was called the

In July 2006, the video coding work of the the voting, placing third overall.

Video coding standards

The organization now known as VCEG has standardized (and is responsible for the maintenance of) the following video compression formats and ancillary standards:

the first digital video coding standard. v1 (1984) featured conditional replenishment, differential PCM, scalar quantization, variable-length coding and a switch for quincunx sampling. v2 (1988) added motion compensation and background prediction. This standard was little-used and no codecs exist.
was the first practical digital video coding standard (late 1990). This design was a pioneering effort, and all subsequent international video coding standards have been based closely on its design. MPEG-1 Part 2 was heavily influenced by this.
it is identical in content to the video part of the ISO/IEC MPEG-2 Part 2 standard (ISO/IEC 13818-2). This standard was developed in a joint partnership between VCEG and MPEG, and thus it became published as a standard of both organizations. ITU-T Recommendation H.262 and ISO/IEC 13818-2 were developed and published as "common text" international standards. As a result, the two documents are completely identical in all aspects.
was developed as an evolutionary improvement based on experience from H.261, and the MPEG-1 and MPEG-2 standards. Its first version was completed in 1995 and provided a suitable replacement for H.261 at all bitrates. MPEG-4 Part 2 is substantially similar to this.
also known as H.263+ or as the 1998 version of H.263, is the informal name of the second edition of the H.263international video coding standard. It retains the entire technical content of the original version of the standard, but enhances H.263 capabilities by adding several annexes which substantially improve encoding efficiency and provide other capabilities (such as enhanced robustness against data loss in the transmission channel). The H.263+ project was completed in late 1997 or early 1998, and was then followed by an "H.263++" project that added a few more enhancements in late 2000.
Advanced Video Coding (AVC) is the most-widely-used standard in the series of international video coding standards. It was developed by a Joint Video Team (JVT) consisting of experts from ITU-T's Video Coding Experts Group (VCEG) and ISO/IEC's Moving Picture Experts Group (MPEG) created in 2001. The ITU-T H.264 standard and the ISO/IEC MPEG-4 Part 10 standard (formally, ISO/IEC 14496-10) are technically identical. The final drafting work on the first version of the standard was completed in May 2003. As has been the case with past standards, its design provides a balance between the coding efficiency, implementation complexity, and cost based on state of VLSI design technology (CPUs, DSPs, ASICs, FPGAs, etc.).
also known as High Efficiency Video Coding (HEVC), completed in January 2013 for its first edition.[2][3][4] HEVC has approximately twice the compression capability of its H.264/MPEG-4 AVC predecessor and was similarly developed with MPEG in a joint team known as the Joint Collaborative Team on Video Coding (JCT-VC). It is also standardized as ISO/IEC 23008-2 (MPEG-H Part 2).
Video back channel messages for conveyance of status information and requests from a video receiver to a video sender

Image coding standards

Starting in late 2006, VCEG has also been responsible for the ITU-T work on still image coding standards including the following:

  • JPEG (ITU-T T.80, T.81, T.83, T.84, T.86, T.871, and T.872) and the JPEG-like ITU-T T.851
  • JBIG-1 (ITU-T T.80, T.82 and T.85)
  • JBIG-2 (ITU-T T.88 and T.89)
  • JPEG-LS (ITU-T T.87 and T.870)
  • JPEG 2000 (ITU-T T.800 through T.813)
  • JPEG XR (ITU-T T.832, T.833, T.834, T.835, and T.Sup2)
  • MRC (ITU-T T.44)

VCEG works on most of these standards jointly with ISO/IEC JTC 1/SC 29/WG 1 (Joint Photographic Experts Group/Joint Bi-level Image experts Group).

See also


External links

  • ITU main site
  • ITU-T Study Group 16 web site
  • ITU-T SG 16 Question 6 web site
  • Official JPEG and JBIG web site
  • Official MPEG web site
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