Coding and decoding apparatus with motion compensation

A coding apparatus with motion compensation comprising:

• a unifier to unify a plurality of motion vectors corresponding to motion of portions of a picture to obtain a first motion vector group arranged in two-dimensional block;
• an arrangement converter to convert motion vectors in the first motion vector group from the two-dimensional block into predetermined one-dimension by scanning to obtain a second motion vector group arranged in the one-dimension;
• a vector predictor to predict a motion vector value in the second motion vector group from at least another motion vector value which has already been predicted in the second motion vector group in the order of the motion vectors converted into the one-dimension to obtain a motion vector predictive residue;
• an encoder to encode the motion vector predictive residue with variable-length codes including zero run length codes to obtain a bitstream per motion vector group;
• and
• wherein the arrangement converter performs arrangement conversion after at least one motion vector not needing to be transferred is extracted from a position between an anterior motion vector and a posterior motion vector to be transferred and the posterior motion vector is shifted to a vacant space given due to the data extraction, leaving no empty space between the anterior and posterior motion vectors.

A decoding apparatus with motion compensation comprising:

• a decoder to decode a bitstream of motion vector groups composed of variable-length codes including zero run length codes to obtain a fixed-length motion vector predictive residue;
• an adder to add a predictive value obtained from at least one motion vector that has already been obtained to the fixed-length motion vector predictive residue to obtain motion vectors as a one-dimensionally arranged motion vector group in the order of the motion vectors that have been converted into one-dimension when coded;
• an arrangement converter to convert the one-dimensionally arranged motion vector group into two-dimension by scanning to obtain a two-dimensionally arranged motion vector group in which motion vectors are unified in vertical and horizontal directions;
• a sequencer to output each vector in the two-dimensionally arranged motion vector group in accordance with motion compensation processing to each portion of a picture;
• and
• wherein the arrangement converter performs arrangement conversion with one of a plurality of scanning patterns selected based on information transferred from a coding apparatus.