VCEG
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The Video Coding Experts Group or VCEG is the Study Group 16, Working Party 3/16 (Media coding) Question 6 (Video coding) of ITU-T. The Study Group 16 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).
The goal of Question 6 is to produce Recommendations for video 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 will focus 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.).
VCEG has standardized the following compression formats and ancillary standards:
- H.120: the first digital video coding standard. v1 (1984) had conditional replenishment, DPCM, scalar quantization, variable-length coding, switch for quincunx sampling. v2 (1988) added motion compensation and background prediction.
- H.261: 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.
- H.262: it is identical in content to the video part of the ISO/IEC MPEG-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.
- H.263: 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.
- H.263v2: 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.
- H.264: Advanced Video Coding (AVC) is the newest entry in the series of international video coding standards. It is currently the most powerful and state-of-the-art standard, and 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 of 2003. As has been the case with past standards, its design provides the most current balance between the coding efficiency, implementation complexity, and cost based on state of VLSI design technology (CPU's, DSP's, ASIC's, FPGA's, etc.
- H.265: Not yet developed; expected 2010 or later.
[edit] See also
- Audio codec
- Video codec
- Video quality
- Video compression
- ITU Telecommunication Standardization Sector
- MPEG
