Methods and systems for intra block copy coding with block vector derivation

Abstract

Systems and methods are described for encoding and decoding video using derived block vectors as predictors in intra block copy mode. In an exemplary encoding method, an encoder identifies at least a first candidate block vector for the prediction of an input video block, where the first candidate block vector points to a first candidate block. The encoder then identifies a first predictive vector (e.g. a block vector or a motion vector) that was used to encode the first candidate block. From the first candidate block vector and the first predictive vector, the encoder generates a derived predictive vector from the first candidate block vector and the first predictive vector. The encoder then encodes the video block in the bit stream using the derived predictive vector for the prediction of the input video block.

What is claimed is: 
     
         1 . A video decoding method comprising:
 decoding a plurality of blocks;   storing information of at least some decoded blocks in a same row as a current block; and   decoding the current block with intra block copy coding based at least in part on the stored information.   
     
     
         2 . The method of  claim 1 , wherein storing information of at least some decoded blocks in a same row as a current block comprises caching information of at least some decoded blocks in a same row as a current block. 
     
     
         3 . The method of  claim 1 , wherein decoding the current block with intra block copy coding comprises:
 decoding a block vector from a bitstream; and   generating a prediction of the current block based on the block vector.   
     
     
         4 . The method of  claim 3 , wherein decoding the current block with intra block copy coding further comprises:
 decoding from the bitstream a residual of the current block; and   adding the residual to the prediction of the current block to generate a reconstructed video block.   
     
     
         5 . The method of  claim 3 , wherein the block vector points to a reference block in the same row as the current block, and wherein the prediction of the current block is based on the reference block. 
     
     
         6 . The method of  claim 1 , wherein the decoded blocks in the same row as the current block are decoded blocks in a same row of coding tree units (CTUs) as the current block. 
     
     
         7 . A video encoding method comprising:
 selecting a block vector for encoding of a current block, wherein the block vector is selected to point to a reference block in a same row as the current block; and   encoding the current block with intra block copy coding using the selected block vector.   
     
     
         8 . The method of  claim 7 , wherein the decoded blocks in the same row as the current block are decoded blocks in a same row of coding tree units (CTUs) as the current block. 
     
     
         9 . The method of  claim 7 , wherein encoding the current block comprises encoding the block vector in a bitstream. 
     
     
         10 . The method of  claim 7 , wherein encoding the current block comprises generating a prediction of the current block based on the block vector. 
     
     
         11 . The method of  claim 10 , wherein encoding the current block further comprise:
 subtracting the prediction of the current block from an input video block to obtain a residual; and   encoding the residual in a bitstream.   
     
     
         12 . A video decoding apparatus comprising a processor configured to perform at least:
 decoding a plurality of blocks;   storing information of at least some decoded blocks in a same row as a current block; and   decoding the current block with intra block copy coding based at least in part on the stored information.   
     
     
         13 . The apparatus of  claim 12 , wherein storing information of at least some decoded blocks in a same row as a current block comprises caching information of at least some decoded blocks in a same row as a current block. 
     
     
         14 . The apparatus of  claim 12 , wherein decoding the current block with intra block copy coding comprises:
 decoding a block vector from a bitstream; and   generating a prediction of the current block based on the block vector.   
     
     
         15 . The apparatus of  claim 14 , wherein decoding the current block with intra block copy coding further comprises:
 decoding from the bitstream a residual of the current block; and   adding the residual to the prediction of the current block to generate a reconstructed video block.   
     
     
         16 . The apparatus of  claim 14 , wherein the block vector points to a reference block in the same row as the current block, and wherein the prediction of the current block is based on the reference block. 
     
     
         17 . The apparatus of  claim 12 , wherein the decoded blocks in the same row as the current block are decoded blocks in a same row of coding tree units (CTUs) as the current block.