H26x

H26x is a shorthand term used to refer collectively to the family of ITU-T video coding standards designated in the H.26x series. It is not a single standard but a progression of specifications developed by ITU-T VCEG and standardized jointly with ISO/IEC MPEG. The series began with H.261 for videotelephony and includes subsequent standards such as H.262 (MPEG-2 Part 2), H.263, H.264 (AVC), H.265 (HEVC), and the later H.266 (VVC). Each generation introduces improved compression efficiency, error resilience, and feature support for higher resolutions and different bitrates.

Applications include videoconferencing, broadcast and streaming video, digital television, and optical media distribution; H26x codecs are implemented in encoders and decoders across devices and software platforms.

Common technical themes across the series are intra- and inter-frame prediction, transform coding, entropy coding, and rate-distortion optimization, with each newer standard offering larger macroblock concepts, more advanced motion compensation, and improved entropy coding to achieve better quality at lower bitrates.

Adoption issues include licensing and patent considerations, hardware acceleration, and compatibility with existing infrastructure. While older members like H.261 and H.262 remain relevant historically, the contemporary emphasis is on H.265/HEVC and H.266/VVC for new deployments.

See also: ITU-T H.26x, video codecs, HEVC, AVC, MPEG-2, VVC. Notes: In other contexts, H26x can denote product codes or model numbers unrelated to video coding.