Setting maximum number of ibc candidates based on maximum number of merge candidates

Abstract

A method of video decoding includes determining whether a maximum number of merge candidates is signaled in a coded video bitstream for a current block of a current picture. The method further includes, in response to a determination that the maximum number of merge candidates is signaled for the current block, setting a maximum number of intra block copy (IBC) candidates for the current block to a value of the signaled maximum number of merge candidates, and, in response to a determination that the maximum number of merge candidates is not signaled for the current block, setting the maximum number of IBC candidates to a predetermined value. The method further includes constructing a candidate list of vector predictors based on at least one of the maximum number of merge candidates or the maximum number of IBC candidates for the current block.

What is claimed is: 
     
         1 . A method of video decoding comprising:
 receiving a coded video bitstream including a current picture;   determining whether a maximum number of merge candidates is signaled in the coded video bitstream for a current block of the current picture;   in response to a determination that the maximum number of merge candidates is signaled for the current block, setting a maximum number of intra block copy (IBC) candidates for the current block to a value of the signaled maximum number of merge candidates;   in response to a determination that the maximum number of merge candidates is not signaled for the current block, setting the maximum number of IBC candidates to a predetermined value;   constructing a candidate list of vector predictors based on at least one of the maximum number of merge candidates or the maximum number of IBC candidates for the current block;   retrieving a vector predictor from the candidate list of vector predictors in accordance with a signaled index; and   decoding the current block in accordance with the retrieved vector predictor.   
     
     
         2 . The method of  claim 1 , wherein the setting the maximum number of IBC candidates is performed in response to a determination that the signaled maximum number of merge candidates is less than an initial value of the maximum number of IBC candidates for the current block. 
     
     
         3 . The method of  claim 2 , wherein the initial value of the maximum number of IBC candidates for the current block is signaled in the coded video bitstream. 
     
     
         4 . The method of  claim 1 , wherein the predetermined value is 6. 
     
     
         5 . The method of  claim 1 , wherein the determining whether the maximum number of merge candidates is signaled is based on whether a slice type of the current block is I, P, or B. 
     
     
         6 . The method of  claim 5 , wherein the maximum number of merge candidates is signaled when the slice type of the current block is P or B. 
     
     
         7 . The method of  claim 5 , wherein the maximum number of merge candidates is not signaled when the slice type of the current block is I. 
     
     
         8 . A video decoding apparatus comprising:
 processing circuitry configured to
 receive a coded video bitstream including a current picture; 
 determine whether a maximum number of merge candidates is signaled in the coded video bitstream for a current block of the current picture; 
 in response to a determination that the maximum number of merge candidates is signaled for the current block, set a maximum number of intra block copy (IBC) candidates for the current block to a value of the signaled maximum number of merge candidates; 
 in response to a determination that the maximum number of merge candidates is not signaled for the current block, set the maximum number of IBC candidates to a predetermined value; 
 construct a candidate list of vector predictors based on at least one of the maximum number of merge candidates or the maximum number of IBC candidates for the current block; 
 retrieve a vector predictor from the candidate list of vector predictors in accordance with a signaled index; and 
 decode the current block in accordance with the retrieved vector predictor. 
   
     
     
         9 . The apparatus of  claim 8 , wherein the processing circuitry is configured to set the maximum number of IBC candidates is performed in response to a determination that the signaled maximum number of merge candidates is less than an initial value of the maximum number of IBC candidates for the current block. 
     
     
         10 . The apparatus of  claim 9 , wherein the initial value of the maximum number of IBC candidates for the current block is signaled in the coded video bitstream. 
     
     
         11 . The apparatus of  claim 8 , wherein the predetermined value is 6. 
     
     
         12 . The apparatus of  claim 8 , wherein the processing circuitry is configured to determine whether the maximum number of merge candidates is signaled based on whether a slice type of the current block is I, P, or B. 
     
     
         13 . The apparatus of  claim 12 , wherein the maximum number of merge candidates is signaled when the slice type of the current block is P or B. 
     
     
         14 . The apparatus of  claim 12 , wherein the maximum number of merge candidates is not signaled when the slice type of the current block is I. 
     
     
         15 . A non-transitory computer-readable storage medium storing computer-readable instructions thereon, which, when executed by processing circuitry, cause the processing circuitry to perform a method of video decoding comprising:
 receiving a coded video bitstream including a current picture;   determining whether a maximum number of merge candidates is signaled in the coded video bitstream for a current block of the current picture;   in response to a determination that the maximum number of merge candidates is signaled for the current block, setting a maximum number of intra block copy (IBC) candidates for the current block to a value of the signaled maximum number of merge candidates;   in response to a determination that the maximum number of merge candidates is not signaled for the current block, setting the maximum number of IBC candidates to a predetermined value;   constructing a candidate list of vector predictors based on at least one of the maximum number of merge candidates or the maximum number of IBC candidates for the current block;   retrieving a vector predictor from the candidate list of vector predictors in accordance with a signaled index; and   decoding the current block in accordance with the retrieved vector predictor.   
     
     
         16 . The computer-readable storage medium of  claim 15 , wherein the setting the maximum number of IBC candidates is performed in response to a determination that the signaled maximum number of merge candidates is less than an initial value of the maximum number of IBC candidates for the current block. 
     
     
         17 . The computer-readable storage medium of  claim 16  wherein the initial value of the maximum number of IBC candidates for the current block is signaled in the coded video bitstream. 
     
     
         18 . The computer-readable storage medium of  claim 15 , wherein the predetermined value is 6. 
     
     
         19 . The computer-readable storage medium of  claim 15 , wherein the determining whether the maximum number of merge candidates is signaled is based on whether a slice type of the current block is I, P, or B. 
     
     
         20 . The computer-readable storage medium of  claim 19 , wherein the maximum number of merge candidates is signaled when the slice type of the current block is P or B.