H264AVC

H.264/AVC, also known as H264AVC, is a video compression standard jointly developed by ITU-T Video Coding Experts Group (VCEG) and ISO/IEC JTC1/SC29/WG11 (MPEG). It was finalized in 2003 and is also designated as MPEG-4 Part 10. The standard provides high compression efficiency and flexibility to support a wide range of applications, from mobile video at low bitrates to high-definition broadcasts and storage formats such as Blu-ray Disc.

H.264 achieves its improved performance through several technical innovations. It uses block-based motion compensation with variable block sizes, advanced intra-prediction, and the option of using multiple reference frames. For entropy coding, it employs context-adaptive binary arithmetic coding (CABAC) or context-adaptive variable-length coding (CAVLC), depending on the profile. An in-loop deblocking filter reduces artifacts that can result from compression, enhancing visual quality.

The standard defines multiple profiles to balance complexity and capability. Baseline, Main, Extended, and High profiles address different use cases, with High offering the most features and efficiency for broadcast and consumer video. Levels specify constraints on bitrate, frame size, and processing requirements to ensure compatibility across devices.

Applications and impact include widespread use in Blu-ray Disc, streaming services, digital television, and video conferencing. H.264 is supported by most hardware decoders and software encoders (for example, x264). The standard’s success spurred ongoing development, with H.265/HEVC as its successor, providing further gains in compression efficiency.

Licensing for H.264 is patent-based, requiring appropriate licensing for implementations and deployments. See also H.265/HEVC and MPEG-4 Part 2.