In this mode the motion vector range is extended to [−31.5, 31.5] , which is particularly useful in improving the compression performance of the algorithm for larger picture sizes. The mode also allows motion vectors to point outside the picture. This is done by repeating the edge pixels to create the picture beyond its boundary
Syntax – Based Arithmetic Coding Mode
In this mode the variable length codes are replaced with an arithmetic coder. The word length for the upper and lower limits is 16. The option specifies several different Cum Count tables that can be used for arithmetic coding. There are separate Cum Count tables for encoding motion vectors, intra DC component, and intra and inter coefficients