Video encoding and decoding using intra block copy

1. A video decoding method of predicting a picture, which is split into equal-sized coding tree blocks, in units of blocks, the video decoding method comprising:

reconstructing a block vector for a current coding block in a current coding tree block to be decoded, by decoding block vector information from a bitstream, wherein the current coding block is one of blocks split from the current coding tree block in a tree structure; and

setting, as a prediction block of the current coding block, a reference block indicated by the block vector in the picture in which the current coding block is located,

wherein a value of the block vector is limited to prevent the reference block from being located outside a search area that is set in at least one of the current coding tree block and a left coding tree block of the current coding tree block, and

the search area is selected from pre-decoded processing regions among a plurality of processing regions which are split in an equal size from each of the current coding tree block and the left coding tree block, and

wherein a processing region of a plurality of processing regions in the left coding tree block, which is co-located with a current processing region including the current coding block, is not set as the search area for the current coding block and a coding block which is included in the current coding tree block and is to be decoded after the current coding block.

2. The video decoding method of claim 1 , wherein the coding tree blocks have a size of 128×128, and the processing regions have a size of 64×64.

3. The video decoding method of claim 1 , wherein the search area is selected on the basis of a position at which the current processing region is located in the current coding tree block.

4. The video decoding method of claim 1 , wherein the search area further includes a pre-decoded portion in a current processing region including the current coding block.

5. The video decoding method of claim 1 , wherein the search area is selected from among the plurality of processing regions which are split in the equal size from each of the current coding tree block and the left coding tree block, by a predetermined number starting from a processing region that has been most recently decoded in a decoding order.

6. The video decoding method of claim 1 , wherein the reconstructing of the block vector comprises:

generating an intermediate block vector using the block vector information; and

compensating for the block vector by adding, to the intermediate block vector, a vector from an upper left sample included in the current coding block to an upper left sample included in a current processing region which includes the current coding block.

7. The video decoding method of claim 1 , wherein, when the block vector is located outside the search area, a clipping operation is performed to modify the block vector to indicate a boundary of the search area.

8. The video decoding method of claim 7 , wherein the clipping operation is performed to modify the block vector to indicate a sample closest to a sample indicated by the block vector among samples on the boundary of the search area.

9. The video decoding method of claim 7 , wherein the clipping operation is performed to scale the block vector to indicate a sample on the boundary of the search area.

10. A video encoding method of predicting a picture, which is split into equal-sized coding tree blocks, in units of blocks, the video encoding method comprising:

determining a block vector of a current coding block of a current coding tree block to be encoded, wherein the current coding block is one of blocks split in a tree structure from the current coding tree block;

setting, as a prediction block of the current coding block, a reference block indicated by the block vector in the picture in which the current coding block is located; and

encoding information about the block vector;

wherein a value of the block vector is limited to prevent the reference block from being located outside a search area that is set in at least one of the current coding tree block and a left coding tree block of the current coding tree block, and

the search area is selected from among pre-encoded processing regions among a plurality of processing regions which are split in an equal size from each of the current coding tree block and the left coding tree block, and

wherein a processing region of a plurality of processing regions in the left coding tree block, which is co-located with a current processing region containing the current coding block within the current coding tree block, is not set as the search area for the current coding block and a coding block which is to be subsequently encoded in the current coding tree block.

11. The video encoding method of claim 10 , wherein the coding tree blocks have a size of 128×128, and the processing regions have a size of 64×64.

12. The video encoding method of claim 10 , wherein the search area is selected on the basis of a position at which the current processing region is located in the current coding tree block.

13. The video encoding method of claim 10 , wherein the search area further comprises a pre-encoded portion in a current processing region including the current coding block.

14. The video encoding method of claim 10 , wherein the search area is selected from among the plurality of processing regions which are split in the equal size from each of the current coding tree block and the left coding tree block, by a predetermined number starting from a processing region which has been most recently encoded in an encoding order.

15. A method for providing a video decoding device with video data the method comprising:

encoding the video data into a bitstream; and

transmitting the bitstream to the video decoding device,

wherein the encoding of the video data includes:

determining a block vector of a current coding block of a current coding tree block to be encoded, wherein the current coding block is one of blocks split in a tree structure from the current coding tree block;

setting, as a prediction block of the current coding block, a reference block indicated by the block vector in the picture in which the current coding block is located; and

encoding information about the block vector,

wherein a value of the block vector is limited to prevent the reference block from being located outside a search area that is set in at least one of the current coding tree block and a left coding tree block of the current coding tree block, and

the search area is selected from among pre-encoded processing regions among a plurality of processing regions which are split in an equal size from each of the current coding tree block and the left coding tree block, and

wherein a processing region of a plurality of processing regions in the left coding tree block, which is co-located with a current processing region containing the current coding block within the current coding tree block, is not set as the search area for the current coding block and a coding block which is to be subsequently encoded in the current coding tree block.