H.264 / MPEG-4 AVC was the product of a partnership between ITU-T Video Coding Experts Group (VCEG) and the ISO/IEC Moving Picture Experts Group (MPEG). The ITU-T H.264 and the ISO/IEC MPEG-4 AVC standards are jointly maintained such that they contain identical technical specifications.
The target of the H.264/AVC project was to create a standard capable of providing good video quality at lower bitrates than existing standards. The specification has a very broad application range that covers all forms of digital compressed video from low bit-rate Internet streaming applications to HDTV broadcast and Digital Cinema applications with nearly lossless compression.
The standard includes a range of technologies for which patents exist. The MPEG LA, a private organisation, administers the collection of royalties on behalf of these patent holders for both encoders and decoders. In 2010 the MPEG LA announced that they will not charge royalties when H.264 is used for free of charge delivery of video over the internet.
H.264 defines a range of standards known as profiles, a compliant implementation supports at least one but not necessarily all profiles.
Constrained Baseline Profile (CBP)
Primarily for low-cost applications, this profile is most typically used in videoconferencing and mobile applications. It corresponds to the subset of features that are in common between the Baseline, Main, and High Profiles described below.
Baseline Profile (BP)
Primarily for low-cost applications that require additional data loss robustness, this profile is used in some videoconferencing and mobile applications. This profile includes all features that are supported in the Constrained Baseline Profile, plus three additional features that can be used for loss robustness (or for other purposes such as low-delay multi-point video stream compositing). The importance of this profile has faded somewhat since the definition of the Constrained Baseline Profile in 2009. All Constrained Baseline Profile bitstreams are also considered to be Baseline Profile bitstreams, as these two profiles share the same profile identifier code value.
Main Profile (MP)
This profile is used for standard-definition digital TV broadcasts that use the MPEG-4 format as defined in the DVB standard. It is not, however, used for high-definition television broadcasts, as the importance of this profile faded when the High Profile was developed in 2004 for that application.
Extended Profile (XP)
Intended as the streaming video profile, this profile has relatively high compression capability and some extra tricks for robustness to data losses and server stream switching.
High Profile (HiP)
The primary profile for broadcast and disc storage applications, particularly for high-definition television applications (for example, this is the profile adopted by the Blu-ray Disc storage format and the DVB HDTV broadcast service).
High 10 Profile (Hi10P)
Going beyond typical mainstream consumer product capabilities, this profile builds on top of the High Profile, adding support for up to 10 bits per sample of decoded picture precision.
High 4:2:2 Profile (Hi422P)
Primarily targeting professional applications that use interlaced video, this profile builds on top of the High 10 Profile, adding support for the 4:2:2 chroma subsampling format while using up to 10 bits per sample of decoded picture precision.
High 4:4:4 Predictive Profile (Hi444PP)
This profile builds on top of the High 4:2:2 Profile, supporting up to 4:4:4 chroma sampling, up to 14 bits per sample, and additionally supporting efficient lossless region coding and the coding of each picture as three separate colour planes.