Information technology -- Coding of audio-visual objects -- Part 10: Advanced Video Coding
ISO/IEC 14496-10:2008 was developed jointly with the ITU-T in response to the growing need for higher compression of moving pictures for various applications such as digital storage media, television broadcasting, Internet streaming, and real-time audiovisual communication. It is also designed to enable the use of the coded video representation in a flexible manner for a wide variety of network environments. It is designed to be generic in the sense that it serves a wide range of applications, bit rates, resolutions, qualities and services. The use of ISO/IEC 14496-10:2008 allows motion video to be manipulated as a form of computer data and to be stored on various storage media, transmitted and received over existing and future networks and distributed on existing and future broadcasting channels. In the course of creating ISO/IEC 14496-10:2008, requirements from a wide variety of applications have been considered, necessary algorithmic elements have been developed, and these have been integrated into a single syntax. Hence, ISO/IEC 14496-10:2008 will facilitate video data interchange among different applications.
The coded representation specified in the syntax is designed to enable a high compression capability with minimal degradation of image quality. The algorithm is not ordinarily lossless, as the exact source sample values are typically not preserved through the encoding and decoding processes. A number of syntactical features with associated decoding processes are defined that can be used to achieve highly efficient compression, and individual selected regions can be sent without loss. The expected encoding algorithm (not specified in ISO/IEC 14496-10:2008) can select between inter and intra coding for block-shaped regions of each picture. Inter coding uses motion vectors for block-based inter-picture prediction to exploit temporal statistical dependencies between different pictures. Intra coding uses spatial prediction modes to exploit spatial statistical dependencies in the source signal within a single picture. Motion vectors and intra prediction modes may be associated with a variety of block sizes in a picture. The residual signal remaining after intra or inter prediction is then processed using a spatial transform to remove spatial correlation within each transform block. The transformed blocks are then quantised. Quantisation is an irreversible process that forms an approximation that can be represented using a reduced number of bits while incurring some loss of fidelity. Finally, the motion vectors or intra prediction modes are combined with the quantised transform coefficient information and encoded using either context-adaptive variable length codes or context-adaptive binary arithmetic coding.
Annexes A through E and G contain normative requirements and are an integral part of ISO/IEC 14496-10:2008. Annex A defines eleven profiles (Baseline, Main, Extended, High, High 10, High 4:2:2, High 4:4:4 Predictive, High 10 Intra, High 4:2:2 Intra, High 4:4:4 Intra, and CAVLC 4:4:4 Intra), each being tailored to a group of application domains, and also defines levels of capability within each of these profiles. Annex B specifies the syntax and semantics of a byte stream format for delivery of the coded video as an ordered stream of bytes or bits. Annex C specifies the Hypothetical Reference Decoder and its use to check bitstream and decoder conformance. Annex D specifies syntax and semantics for Supplemental Enhancement Information message payloads. Annex E specifies syntax and semantics of the Video Usability Information parameters of coded video sequences. Annex G specifies scalable video coding in three additional profiles (Scalable Baseline, Scalable High, and Scalable High Intra) which enable a coded video bitstream to be structured into layers, such that layered subsets of the bitstream can be independently decodable to provide video quality commensurate with the quantity of data that remains in each smaller bitstream.
ISO/IEC 14496-10:2008 is the fourth edition of the ISO/IEC 14496-10 specification. It includes the same technical material specified in the first edition (ISO/IEC 14496-10:2003), plus the following:
– integrated errata corrections that were specified in corrigenda of 2004, 2005, and 2006.
– enhancements primarily for high-resolution, high-quality video applications that were specified in a 2004 amendment referred to as "Fidelity Range Extensions" and a 2007 amendment referred to as "Professional Application Extensions".
– enhancements supporting additional color spaces and aspect ratio definitions specified in a 2007 amendment.
enhancements supporting scalable video coding as specified in a 2007 amendment.