Abstract :
This article provides an overview of H.263, the new ITU-T Recommendation for low-bit-rate video communication. H.263 specifies a coded representation for compressing the moving picture component of audio-visual signals at low bit rates. The basic structure of the video source coding algorithm is taken from ITU-T Recommendation H.261 and is a hybrid of interpicture prediction to reduce temporal redundancy and transform coding of the prediction residual to reduce spatial redundancy. The source coder can operate on five standardized picture formats: sub-QCIF, QCIF, CIF, 4CIF, and 16CIF. The decoder has motion compensation capability with half-pixel precision, in contrast to H.261 which uses full-pixel precision and employs a loop filter. H.263 includes four negotiable coding options which provide improved coding efficiency: unrestricted motion vectors, syntax-based arithmetic coding, advanced prediction, and PB-frames
Keywords :
arithmetic codes; decoding; image representation; motion compensation; prediction theory; source coding; telecommunication standards; transform coding; video coding; 16CIF format; 4CIF format; CIF format; H.263; ITU-T Recommendation H.261; ITU-T recommendation; PB frames; QCIF format; advanced prediction; audio-visual signals; compression; decoder; half-pixel precision; interpicture prediction; low-bit-rate communication; motion compensation; moving picture component; negotiable coding options; representation; source coder; spatial redundancy; standardized picture formats; sub QCIF format; temporal redundancy; transform coding; unrestricted motion vectors; video coding; video communication; video source coding algorithm; Bit rate; Discrete cosine transforms; Proposals; Scheduling; Telecommunication standards; Telephony; Transform coding; Video coding; Videoconference; Wireless networks;
