Advanced Video Coding: Difference between revisions

Revision as of 06:09, 15 January 2024

Revision as of 14:06, 15 January 2024

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== Naming ==

The H.264 name follows the [[ITU-T]] [[ITU-T#Recommendation categorization|naming convention]], where Recommendations are given a letter corresponding to their series and a recommendation number within the series. H.264 is part of "H-Series Recommendations: Audiovisual and multimedia systems". H.264 is further categorized into "H.200-H.499: Infrastructure of audiovisual services" and "H.260-H.279: [[Video encoding|Coding]] of moving video".<ref>{{Cite web |title=ITU-T Recommendations |url=https://www.itu.int:443/en/ITU-T/publications/Pages/recs.aspx |access-date=2022-11-01 |website=ITU |language=en-US}}</ref> The MPEG-4 AVC name relates to the naming convention in [[International Organization for Standardization|ISO]]/[[International Electrotechnical Commission|IEC]] [[MPEG]], where the standard is part 10 of ISO/IEC 14496, which is the suite of standards known as MPEG-4. The standard was developed jointly in a partnership ofwith VCEG and MPEG, after earlier development work in the ITU-T as a VCEG project called H.26L. It is thus common to refer to the standard with names such as H.264/AVC, AVC/H.264, H.264/MPEG-4 AVC, or MPEG-4/H.264 AVC, to emphasize the common heritage. Occasionally, it is also referred to as "the JVT codec", in reference to the Joint Video Team (JVT) organization that developed it. (Such partnership and multiple naming is not uncommon. For example, the video compression standard known as MPEG-2 also arose from the partnership between [[MPEG]] and the ITU-T, where MPEG-2 video is known to the ITU-T community as H.262.<ref>{{cite web|url=http://itu.int/rec/T-REC-H.262|title=H.262 : Information technology&nbsp;— Generic coding of moving pictures and associated audio information: Video|access-date=2007-04-15}}</ref>) Some software programs (such as [[VLC media player]]) internally identify this standard as AVC1.

== History ==

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In December 2001, VCEG and the Moving Picture Experts Group ([[MPEG]]&nbsp;– [[ISO/IEC JTC 1/SC 29]]/WG 11) formed a Joint Video Team (JVT), with the charter to finalize the video coding standard.<ref name=JVTsite>[http://www.itu.int/en/ITU-T/studygroups/com16/video/Pages/jvt.aspx Joint Video Team], [[ITU-T]] Web site.</ref> Formal approval of the specification came in March 2003. The JVT was (is) chaired by [[Gary Sullivan (engineer)|Gary Sullivan]], [[Thomas Wiegand]], and Ajay Luthra ([[Motorola]], U.S.: later [[Arris Group|Arris]], U.S.). In July 2004, the Fidelity Range Extensions (FRExt) project was finalized. From January 2005 to November 2007, the JVT was working on an extension of H.264/AVC towards scalability by an Annex (G) called [[Scalable Video Coding]] (SVC). The JVT management team was extended by [[Jens-Rainer Ohm]] ([[RWTH Aachen University]], Germany). From July 2006 to November 2009, the JVT worked on [[Multiview Video Coding]] (MVC), an extension of H.264/AVC towards [[3D television]] and limited-range [[free-viewpoint television]]. That work included the development of two new profiles of the standard: the Multiview High Profile and the Stereo High Profile.

Throughout the development of the standard, additional messages for containing supplemental enhancement information (SEI) have been developed. SEI messages can contain various types of data that indicate the timing of the video pictures or describe various properties of the coded video or how it can be used or enhanced. SEI messages are also defined that can contain arbitrary user-defined data. SEI messages do not affect the core decoding process, but can indicate how the video is recommended to be post-processed or displayed. Some other high-level properties of the video content are conveyed in video usability information (VUI), such as the indication of the [[color space]] for interpretation of the video content. As new color spaces have been developed, such as for [[High-dynamic-range video|high dynamic range]] and [[wide color gamut]] video, additional VUI identifiers have been added to indicate them.

=== Fidelity range extensions and professional profiles ===