Video Coding - H.263

H. 263 is a standard draft of the ITU-T ITU-T and is designed for low-stream communication. But in reality this standard can be used in a wide range of code streams, not just for low-stream applications, and it can be considered to be used in place of H in many applications. 261. H. 263 encoding algorithm and H. Like 261, but made some improvements and changes to improve performance and error correction capabilities. . The 263 standard can provide a ratio H at low code rates. 261 better image effects, the difference between the two are: (1) H. The motion compensation of 263 uses half-pixel precision, and H. 261 uses full pixel precision and loop filtering; (2) some parts of the data flow hierarchy are in H. 263 is optional, so that the codec can be configured to a lower data rate or better error correction capability; (3) H. 263 contains four negotiable options to improve performance; (4)H. 263 uses an unconstrained motion vector and grammar-based arithmetic coding; (5) uses a prior prediction and frame prediction method that is the same as the PB frame in MPEG; (6) H. The 263 supports five resolutions, which are in addition to supporting H. In addition to the QCIF and CIF supported in 261, SQCIF, 4CIF, and 16CIF are also supported. SQCIF is equivalent to half the resolution of QCIF, and 4CIF and 16CIF are 4 and 16 times that of CIF, respectively.

IUT-T introduced H in 1998. 263+ is H. The second edition of the 263 proposal, which provides 12 new negotiable models and other features, further improves compression coding performance. Such as H. 263 only has 5 video source formats, H. The 263+ allows the use of more source formats, and the image clock frequency also has multiple options to broaden the application range; another important improvement is scalability, which allows multiple display rates, multiple rates and multiple resolutions, and enhances video information in the easy Error code and packet loss are transmitted in a heterogeneous network environment. In addition, H. 263+ to H. The unconstrained motion vector mode in 263 has been improved, and 12 new optional modes have been added, which not only improves coding performance but also enhances application flexibility. H. 263 has basically replaced H. 261.