【Claim 1】
A moving image decoding device which decodes a bit stream generated by dividing an image of a moving image into a plurality of blocks and by compression-encoding the blocks and obtains the moving image, the moving image decoding device comprising:
a motion-compensated predictor to generate an inter prediction image of one of the blocks on a basis of encoding mode information indicating a sub-block assignment for inter prediction processing on the block ; and
a variable-length decoder to entropy-decode the bit stream in order to obtain a binary string and obtain the encoding mode information from the binary string,
wherein the variable-length decoder obtains an identifier from bit stream, the identifier specifying a table from a plurality of binarization tables each of which defines a binary string assignment to the encoding mode information, and obtains the encoding mode information by inverse binarizing the binary string in accordance with the specified binarization table. 【Claim 2】
A moving image decoding method for decoding a bit stream generated by dividing an image of a moving image into a plurality of blocks and by compression-encoding the blocks and obtains the moving image, the moving image decoding method comprising:
obtaining a binary string by entropy-decoding the bit stream;
obtaining encoding mode information by inverse binarizing the binary string in accordance with a binarization table which is specified from a plurality of binarization tables each of which defines a binary string assignment to the encoding mode information, the identifier being obtained from the bit stream; and
generating an inter prediction images of one of the blocks on a basis of the encoding mode information, the encoding mode information indicating a sub-block assignment for inter prediction processing on the block. 【Claim 3】
A moving image encoding device which generates a bit stream by dividing an image

of a moving image into a plurality of blocks and by compression-encoding the blocks, the moving image encoding device comprising:
a motion-compensated predictor to generate an inter prediction images of one of the blocks on a basis of encoding mode information indicating a sub-block assignment for inter prediction processing on the block; and
a variable-length encoder to binarize the encoding mode information to a binary string and entropy-encode the binary string into the bit stream,
wherein the variable-length encoder carries out the binarization according to a binarization table specified with an identifier from a plurality of binarization tables, each of which defines a binary string assignment to the encoding mode information, and encodes the identifier into a bit stream. 【Claim 4】
A moving image encoding method of generating a bit stream by dividing an image of a moving image into a plurality of blocks and by compression-encoding the blocks, the moving image encoding method comprising:
generating an inter prediction image of one of the blocks on a basis of encoding mode information indicating a sub-block assignment for inter prediction processing on the block ;
binarizing the encoding mode information to a binary string in accordance with a binarization table which is specified with an identifier from a plurality of binarization tables each of which defines a binary string assignment to the encoding mode information, the identifier being encoded into the bit stream; and
entropy-encoding the binary string into a bit stream.