MOVING PICTURE ENCODING APPARATUS, MOVING PICTURE ENCODING METHOD, AND MOVING PICTURE ENCODING PROGRAM, AND MOVING PICTURE DECODING APPARATUS, MOVING PICTURE DECODING METHOD, AND MOVING PICTURE DECODING PROGRAM

1 . A moving picture encoding apparatus, comprising:

a provisional region dividing unit configured to divide a block to be encoded into a plurality of provisional regions on a predetermined provisional boundary;

a motion vector detecting unit configured to detect a motion vector with respect to each provisional region;

a motion compensating unit configured to generate a synthesized prediction block by generating a plurality of prediction blocks corresponding to the block to be encoded from a reference image by using the motion vector of each provisional region, deciding an actual boundary based on the plurality of prediction blocks, and joining regions acquired by dividing the each prediction block on the actual boundary among the respective prediction blocks; and

an encoding unit configured to encode a prediction difference block acquired by subtracting the synthesized prediction block from the block to be encoded and the motion vector of each provisional region.

2 . The moving picture encoding apparatus according to claim 1 , wherein the motion compensating unit decides the actual boundary in such a manner that the regions acquired by dividing the each prediction block on the actual boundary are asymmetric.

3 . The moving picture encoding apparatus according to claim 1 , wherein the motion compensating unit decides the actual boundary based on activities of the plurality of prediction blocks.

4 . The moving picture encoding apparatus according to claim 3 , wherein

the motion compensating unit calculates an evaluation value corresponding to an actual boundary candidate based on activities among respective adjacent pixels of the plurality of prediction blocks and decides an actual boundary among a plurality of actual boundary candidates by using the evaluation value.

5 . A moving picture encoding method, comprising:

dividing a block to be encoded into a plurality of provisional regions on a predetermined provisional boundary;

detecting a motion vector with respect to each provisional region;

generating a synthesized prediction block by generating a plurality of prediction blocks corresponding to the block to be encoded from a reference image by using the motion vector of each provisional region, deciding an actual boundary based on the plurality of prediction blocks, and joining regions acquired by dividing the each prediction block on the actual boundary among the respective prediction blocks; and

encoding a prediction difference block acquired by subtracting the synthesized prediction block from the block to be encoded and the motion vector of each provisional region.

6 . The moving picture encoding method according to claim 5 , wherein said generating a synthesized prediction block decides the actual boundary in such a manner that the regions acquired by dividing the each prediction block on the actual boundary are asymmetric.

7 . A non-transitory computer readable medium storing a moving picture encoding program that allows a computer to execute functions, comprising:

a function of dividing a block to be encoded into a plurality of provisional regions on a predetermined provisional boundary;

a function of detecting a motion vector with respect to each provisional region;

a function of generating a synthesized prediction block by generating a plurality of prediction blocks corresponding to the block to be encoded from a reference image by using the motion vector of each provisional region, deciding an actual boundary based on the plurality of prediction blocks, and joining regions acquired by dividing the each prediction block on the actual boundary among the respective prediction blocks; and

a function of encoding a prediction difference block acquired by subtracting the synthesized prediction block from the block to be encoded and the motion vector of each provisional region.

8 . The non-transitory computer readable medium according to claim 7 , wherein the function of generating a synthesized prediction block decides the actual boundary in such a manner that the regions acquired by dividing the each prediction block on the actual boundary are asymmetric.

9 . A moving picture decoding apparatus, comprising:

a decoding unit configured to decode a plurality of motion vectors for a block to be decoded, from an encoded stream;

a motion compensating unit configured to generate a synthesized prediction block by using a plurality of motion vectors, generating a plurality of prediction blocks corresponding to the block to be decoded from a reference image, deciding a boundary based on the plurality of prediction blocks, and joining regions acquired by dividing the each prediction block on the boundary among the respective prediction blocks; and

an addition unit configured to generate a decoded image by adding the synthesized prediction block and the decoded prediction difference block from the block to be decoded.

10 . The moving picture decoding apparatus according to claim 9 , wherein the motion compensating unit decides the boundary in such a manner that the regions acquired by dividing the each prediction block on the boundary are asymmetric.

11 . The moving picture decoding apparatus according to claim 9 , wherein the motion compensating unit decides the boundary based on activities of the plurality of prediction blocks.

12 . The moving picture decoding apparatus according to claim 11 , wherein

the motion compensating unit calculates an evaluation value corresponding to a boundary candidate based on activities among respective adjacent pixels of the plurality of prediction blocks and decides a boundary among a plurality of boundary candidates by using the evaluation value.

13 . A moving picture decoding method, comprising:

decoding a plurality of motion vectors for a block to be decoded, from an encoded stream;

generating a synthesized prediction block by using a plurality of motion vectors, generating a plurality of prediction blocks corresponding to the block to be decoded from a reference image, deciding a boundary based on the plurality of prediction blocks, and joining regions acquired by dividing the each prediction block on the boundary among the respective prediction blocks; and

generating a decoded image by adding the synthesized prediction block and the decoded prediction difference block from the block to be decoded.

14 . The moving picture decoding method according to claim 13 , wherein said generating a synthesized prediction block decides the boundary in such a manner that the regions acquired by dividing the each prediction block on the boundary are asymmetric.

15 . A non-transitory computer readable medium storing a moving picture decoding program that allows a computer to execute functions, comprising:

a function of decoding a plurality of motion vectors for a block to be decoded, from an encoded stream;

a function of generating a synthesized prediction block by using a plurality of motion vectors, generating a plurality of prediction blocks corresponding to the block to be decoded from a reference image, deciding a boundary based on the plurality of prediction blocks, and joining regions acquired by dividing the each prediction block on the boundary among the respective prediction blocks; and

a function of generating a decoded image by adding the synthesized prediction block and the decoded prediction difference block from the block to be decoded.

16 . The non-transitory computer readable medium according to claim 15 , wherein the function of generating a synthesized prediction block decides the boundary in such a manner that the regions acquired by dividing the each prediction block on the boundary are asymmetric.