tors to be considered. This is quite useful in the case of rapid camera movement. Syntax-based Arithmetic Coding can be substituted in H.263 for Variable Length Coding. This allows the compression process that takes place after Huffman encoding to be based on unique aspects of the motion sequence, (rather than relying on a single "codebook"). Advance Prediction is an optional mode with which a codec can use overlapping block motion compensation for creation of P-frames. Four eight-by-eight vectors can be substituted for a 16-by-16 macroblock. The encoder must determine which type of vectors to use. Four vectors generate more bits but give much better prediction. Advance Prediction coding also results in fewer blocking artifacts. H.264 The formal name for H.264 is "Advanced video coding for generic audiovisual services," and it is also known as "MPEG-4/AVC", "MPEG-4 Part 10," and "H.264L." It is an ITU standard for compressing a videoconferencing transmission. Based on MPEG-4, H.264 uses Advanced Video Coding (AVC) for as much as a 70% reduction in bandwidth over H.263. Although H.264 created tension between MPEG4 and H.263 advocates, it is a triumph of the ITU-T Video Coding Experts Group (VCEG) and the ISO/IEC Moving Picture Experts Group (MPEG), which collaborated as the Joint Video Team (JVT). H.264, a high compression digital video codec, is identical to ISO MPEG-4 Part 10, and is also known as AVC, for Advanced Video Coding. The group completed the final draft of the first version of the standard in May 2003. The H.264 name reflects the standard's ITU-T lineage, and the AVC moniker reflects its ISO/IEC MPEG heritage. Multiple names might lead one to infer that such a collaboration is uncommon, but MPEG and the ITU-T previously worked together to develop the MPEG-2 video standard, which is also known as H.262. The H.264/AVC project goal was to create an easily-implementable standard that could provide good video quality at half or less the bit rates that MPEG-2, H.263, or MPEG-4 part 2 require. The authors in