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h264 documentation h264 related products hdmi videophone downlods video4linux programming h264help offshoring events contact us ( 19 mai, 2010 ) h.264/mpeg-4 avc (english) h.264/avc/mpeg-4 part 10 (advanced video coding) is a standard for video compression . the final drafting work on the first version of the standard was completed in may 2003. h.264/avc is the latest block-oriented motion-compensation -based codec standard developed by the itu-t video coding experts group (vceg) together with the iso / iec moving picture experts group (mpeg), and it was the product of a partnership effort known as the joint video team (jvt). the itu-t h.264 standard and the iso/iec mpeg-4 avc standard (formally, iso/iec 14496-10 – mpeg-4 part 10, advanced video coding) are jointly maintained so that they have identical technical content. h.264 is used in such applications as blu-ray disc , videos from youtube and the itunes store , dvb broadcast, direct-broadcast satellite television service, cable television services, and real-time videoconferencing. overview the intent of the h.264/avc project was to create a standard capable of providing good video quality at substantially lower bit rates than previous standards (e.g. half or less the bit rate of mpeg-2 , h.263 , or mpeg-4 part 2 ), without increasing the complexity of design so much that it would be impractical or excessively expensive to implement. an additional goal was to provide enough flexibility to allow the standard to be applied to a wide variety of applications on a wide variety of networks and systems, including low and high bit rates, low and high resolution video, broadcast , dvd storage, rtp / ip packet networks, and itu-t multimedia telephony systems. the h.264 standard can be viewed as a « family of standards », the members of which are the profiles described below. a specific decoder decodes at least one, but not necessarily all profiles. the decoder specification describes which of the profiles can be decoded. the h.264 name follows the itu-t naming convention, where the standard is a member of the h.26x line of vceg video coding standards; the mpeg-4 avc name relates to the naming convention in iso / 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 of 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. the name h.26l, referring to its itu-t history, is less common, but sometimes still encountered. 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 codec 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. [ 1 ] ) some software programs (such as vlc media player) internally identify this standard as avc1. the standardization of the first version of h.264/avc was completed in may 2003. in the first project to extend the original standard, the jvt then developed what was called the fidelity range extensions (frext). these extensions enabled higher quality video coding by supporting increased sample bit depth precision and higher-resolution color information, including sampling structures known as y’cbcr 4:2:2 (= yuv 4:2:2 ) and y’cbcr 4:4:4. several other features were also included in the fidelity range extensions project, such as adaptive switching between 4×4 and 8×8 integer transforms, encoder-specified perceptual-based quantization weighting matrices, efficient inter-picture lossless coding, and support of additional color spaces. the design work on the fidelity range extensions was completed in july 2004, and the drafting work on them was completed in september 2004. further recent extensions of the standard then included adding five other new profiles intended primarily for professional applications, adding extended-gamut color space support, defining additional aspect ratio indicators, defining two additional types of « supplemental enhancement information » (post-filter hint and tone mapping), and deprecating one of the prior frext profiles that industry feedback indicated should have been designed differently. the next major feature added to the standard was scalable video coding (svc). specified in annex g of h.264/avc, svc allows the construction of bitstreams that contain sub-bitstreams that also conform to the standard, including one such bitstream known as the « base layer » that can be decoded by an h.264/avc that does not support svc. for temporal bitstream scalability, i.e., the presence of a sub-bitstream with a smaller temporal sampling rate than the bitstream, complete access units are removed from the bitstream when deriving the sub-bitstream. in this case, high-level syntax and inter prediction reference pictures in the bitstream are constructed accordingly. for spatial and quality bitstream scalability, i.e. the presence of a sub-bitstream with lower spatial resolution or quality than the bitstream, nal ( network abstraction layer ) removed from the bitstream when deriving the sub-bitstream. in this case, inter-layer prediction, i.e., the prediction of the higher spatial resolution or quality signal by data of the lower spatial resolution or quality signal, is typically used for efficient coding. the scalable video coding extensions were completed in november 2007. the next major feature added to the standard was multiview video coding (mvc). specified in annex h of h.264/avc, mvc enables the construction of bitstreams that represent more than one view of a video scene. an important example of this functionality is stereoscopic 3d video coding. two profiles were developed in the mvc work: one supporting an arbitrary number of views and designed specifically for two-view stereoscopic video. the multiview video coding extensions were completed in november 2009. standardization committee and history in early 1998 the video coding experts group ( vceg – itu-t sg16 q.6) issued a call for proposals on a project called h.26l , with the target to double the coding efficiency (which means halving the bit rate necessary for a given level of fidelity) in comparison to any other existing video coding standards for a broad variety of applications. vceg was chaired by gary sullivan ( microsoft [formerly picturetel], usa). the first draft design for that new standard was adopted in august 1999. in 2000, thomas wiegand (heinrich hertz institute, germany) became vceg co-chair. in december 2001, vceg and the moving picture experts group ( mpeg – iso/iec jtc 1 /sc 29/wg 11) formed a joint video team ( jvt ), with the charter to finalize the video coding standard. formal approval of the specification came in march 2003. the jvt was (is) chaired by gary sullivan , thomas wiegand , and ajay luthra (motorola, usa). in june 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-reiner ohm (aachen university, germany). from july 2006 to november 2009, the jvt worked on multiview video coding (mvc), an extension of h.264/avc towards free viewpoint television and 3d television . that work included the development of two new profiles of the standard: the multiview high profile and the stereo high profile. applications further information: list of video services using h.264/mpeg-4 avc the h.264 video format has a very broad application range that covers all forms of digital compressed video from low bit-rate internet streaming applications
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