MPEG4AVC

MPEG4AVC, officially known as MPEG-4 Part 10 Advanced Video Coding (AVC), and commonly referred to as H.264 or AVC, is a widely used video compression standard developed jointly by ITU-T Video Coding Experts Group and ISO/IEC Moving Picture Experts Group. It was finalized in 2003 as part of the MPEG-4 family and is designed to deliver high compression efficiency across a broad range of applications and bitrates while maintaining broad interoperability.

The encoder employs block-based motion compensation with variable block sizes, inter- and intra-prediction, multiple reference frames, and transform and quantization. It uses a deblocking filter to reduce artifacts and supports sub-pixel motion estimation (half- and quarter-pixel) to improve prediction accuracy. For entropy coding, AVC offers CABAC in higher profiles and CAVLC in others, contributing to efficiency at different complexity levels.

MPEG4AVC defines several profiles, including Baseline, Main, Extended, and High, with levels that specify constraints on resolution, bitrate, and processing requirements. The Baseline profile emphasizes low complexity suitable for mobile and video-conferencing, while the High profile targets high-definition content and professional use.

Applications and impact: AVC became the dominant standard for digital video for many years, underpinning Blu-ray Discs, a large portion of streaming video, broadcast television, video conferencing, and mobile video. Its balance of strong compression efficiency and broad hardware and software support contributed to widespread adoption, and it remains in use alongside more recent codecs, though often complemented by newer technologies in modern systems.

Licensing and patents: implementations of MPEG4AVC are subject to patent coverage, managed by various patent pools and organizations such as MPEG LA. Developers and distributors typically obtain necessary licenses to deploy AVC encoders and decoders.