Method and device for encoding/decoding image by inter prediction using random block

1. A video encoding apparatus, comprising:

a block partitioning unit configured to determine a partition form, among candidate partition forms, for partitioning a current block into one or more partition blocks, wherein the candidate partition forms include one or more asymmetric partition forms in which the current block is partitioned into a plurality of asymmetric partition blocks;

a prediction unit configured to generate one or more predicted blocks respectively corresponding to the one or more partition blocks by

determining a motion vector of a partition block partitioned from the current block, and

predicting the partition block using the motion vector and a scale factor which indicates a ratio of pixel sampling, wherein the partition block is predicted from samples in a reference picture which are located at pixel positions identified by both of the motion vector and the scale factor;

a subtractor configured to generate a residual block of the current block by subtracting the predicted blocks from one or more partition blocks corresponding thereto;

a transformer configured to generate at least one transform block by transforming the residual block;

a quantizer configured to generate at least one quantized transform block by quantizing the at least one transform block; and

an encoder configured to encode, into the bitstream, information on the scale factor, information on the determined partition form, information on the motion vector and the at least one quantized transform block.

2. The video encoding apparatus of claim 1 , wherein the information on the partition form is defined by a slope of a partition boundary of the current block and at least one of a length or a start position of the partition boundary.

3. The video encoding apparatus of claim 1 , wherein the pixel positions are identified by sampling pixels from the reference picture in a scale corresponding to the scale factor from a pixel location indicated by the motion vector of the partition block.

4. The video encoding apparatus of claim 1 , wherein the asymmetric partition forms include partition forms for partitioning the current block into two partition blocks, one of the two partition blocks having a rectangular shape in ¼ size of the current block and the other block having a rectangular shape in ¾ size of the current block.

5. A video decoding apparatus, comprising:

a decoder configured to reconstruct, from the bitstream, information on a scale factor which indicates a ratio of pixel sampling, information on a partition form, motion vector information and at least one quantized transform block;

a dequantizer configured to generate at least one transform block by dequantizing the at least one quantized transform block;

an inverse transformer configured to reconstruct a residual block of a current block to be decoded, by inversely transforming the at least one transform block;

a prediction unit configured to

divide the current block into one or more partition blocks according to a partition form indicated by the information on the partition form among candidate partition forms, wherein the candidate partition forms include one or more asymmetric partition forms in which the current block is partitioned into a plurality of asymmetric partition blocks,

generate one or more predicted partition blocks respectively corresponding to the one or more partition blocks by

determining a motion vector of a partition block divided from the current block using the motion vector information,

predicting the partition block using the motion vector and the scale factor, wherein the partition block is predicted from samples in a reference picture which are located at pixel positions identified by both of the motion vector and the scale factor; and

an adder configured to reconstruct the current block based on the reconstructed residual block and the predicted partition blocks.

6. The video decoding apparatus of claim 5 , wherein the information on the partition form is defined by a slope of a partition boundary of the current block and at least one of a length or a start position of the partition boundary.

7. The video decoding apparatus of claim 5 , wherein the pixel positions are identified by sampling pixels from a reference picture in a scale corresponding to the scale factor from a pixel location indicated by the motion vector of the partition block.

8. The video decoding apparatus of claim 5 , wherein the asymmetric partition forms include partition forms for partitioning the current block into two partition blocks, one of the two partition blocks having a rectangular shape in ¼ size of the current block and the other block having a rectangular shape in ¾ size of the current block.

9. A video decoding method performed by a video decoding apparatus, the method comprising:

reconstructing, from a bitstream, information on a scale factor which indicates a ratio of pixel sampling, information on a partition form, motion vector information and at least one quantized transform block;

generating a predicted block of a current block to be decoded; and

generating at least one transform block by dequantizing the least one quantized transform block;

reconstructing a residual block of the current block, based on inversely transforming the least one transform block;

reconstructing the current block based on the reconstructed residual block and the predicted block,

wherein the generating of the predicted block comprises:

dividing the current block into one or more partition blocks according to a partition form indicated by the information on the partition form among candidate partition forms, wherein the candidate partition forms include one or more asymmetric partition forms in which the current block is partitioned into a plurality of asymmetric partition blocks;

determining a motion vector of a partition block partitioned from the current block using the motion vector information;

predicting the partition block divided from the current block using the motion vector and the scale factor, wherein the partition block is predicted from samples in a reference picture which are located at pixel positions identified by both of the motion vector and the scale factor.

10. The video decoding method of claim 9 , wherein the information on the partition form is defined by a slope of a partition boundary of the current block and at least one of a length or a start position of the partition boundary.

11. The video decoding method of claim 9 , wherein the pixel positions are identified by sampling pixels from a reference picture in a scale corresponding to the scale factor from a pixel location indicated by the motion vector of the partition block.

12. The video decoding method of claim 9 , wherein the asymmetric partition forms include partition forms for partitioning the current block into two partition blocks, one of the two partition blocks having a rectangular shape in ¼ size of the current block and the other block having a rectangular shape in ¾ size of the current block.