Difference calculation based on partial position

Abstract

Difference calculation based on partial position is described. In a representative aspect, a method of video processing comprising: calculating, during a conversion between a current block of video and a bitstream representation of the current block, differences between two reference blocks associated with the current block or differences between two reference sub-blocks associated with a sub-block within the current block based on representative positions of the reference blocks or representative positions of the reference sub-blocks; and performing the conversion based on the differences.

What is claimed is: 
     
         1 . A method of video processing, comprising:
 determining an enablement of a first tool, for a conversion between a current block and a bitstream based on a rule, wherein the rule indicates that the first tool and a second tool are not both used by the current block; and   performing, based on the determining, a conversion between the current block and the bitstream;   wherein one of the first tool and the second tool is a decoder side motion vector derivation tool to derive a refinement of motion information related to the current block, and   
       the other of the first tool and the second tool comprises:
 a combined inter and intra prediction tool in which a prediction signal of a block is generated at least based on an intra prediction signal and an inter prediction signal. 
 
     
     
         2 . The method of  claim 1 , wherein the decoder side motion vector derivation tool is disabled upon a determination that the combined inter and intra prediction tool is used for the current block. 
     
     
         3 . The method of  claim 1 , wherein the other of the first tool and the second tool further comprises:
 a merge mode with motion vector differences which comprises motion vector expression comprising a first parameter representing a motion vector difference and a second parameter indicating a base candidate, wherein the first parameter comprises a motion magnitude and a motion direction.   
     
     
         4 . The method of  claim 3 , wherein the decoder side motion vector derivation tool is disabled upon a determination that the current block is coded with the merge mode with motion vector differences. 
     
     
         5 . The method of  claim 1 , wherein the other of the first tool and the second tool further comprises:
 a geometric partitioning tool comprising a partition scheme which divides a block in to two partitions, at least one of which is non-square and non-rectangular.   
     
     
         6 . The method of  claim 5 , wherein the geometric partitioning tool is a triangular prediction tool. 
     
     
         7 . The method of  claim 1 , wherein the decoder side motion vector derivation tool comprises a decoder side motion vector refinement tool. 
     
     
         8 . The method of  claim 1 , wherein the decoder side motion vector derivation tool comprises a bi-directional optical flow tool. 
     
     
         9 . The method of  claim 1 , wherein the first tool is the decoder side motion vector derivation tool, and the conversion comprises:
 dividing the current block into at least one subblock;   calculating differences between two reference subblocks associated with a subblock within the current block based on representative positions of the reference subblocks;   deriving the refinement of the motion information based on the differences.   
     
     
         10 . The method of  claim 9 , wherein the differences are calculated in an early termination stage of the first tool. 
     
     
         11 . The method of  claim 9 , wherein calculating differences comprises:
 calculating differences of specific rows of two reference subblocks.   
     
     
         12 . The method of  claim 11 , wherein the specific rows are composed of one row of every N rows, wherein N is greater than 1. 
     
     
         13 . The method of  claim 11 , wherein N is equal to 2. 
     
     
         14 . The method of  claim 9 , wherein the representative positions are selected by using predetermined strategy. 
     
     
         15 . The method of  claim 9 , wherein deriving the refinement of the motion information based on the differences comprises:
 summing up the differences calculated for the representative positions of the reference sub-blocks to obtain the difference for the sub-block;   deriving the refinement of the motion information using the difference for the subblock.   
     
     
         16 . The method of  claim 15 , wherein the difference for the subblock include sum of absolute differences (SAD) of the representative positions. 
     
     
         17 . An apparatus for processing video data comprising a processor and a non-transitory memory with instructions thereon, wherein the instructions upon execution by the processor, cause the processor to:
 determine an enablement of a first tool, for a conversion between a current block and a bitstream based on a rule, wherein the rule indicates that the first tool and a second tool are not both used by the current block; and   perform, based on the determining, a conversion between the current block and the bitstream;   wherein one of the first tool and the second tool is a decoder side motion vector derivation tool to derive a refinement of motion information related to the current block, and   
       the other of the first tool and the second tool comprises:
 a combined inter and intra prediction tool in which a prediction signal of a block is generated at least based on an intra prediction signal and an inter prediction signal. 
 
     
     
         18 . The apparatus of  claim 17 , wherein the other of the first tool and the second tool further comprises:
 a merge mode with motion vector differences which comprises motion vector expression comprising a first parameter representing a motion vector difference and a second parameter indicating a base candidate, wherein the first parameter comprises a motion magnitude and a motion direction.   
     
     
         19 . A non-transitory computer-readable storage medium storing instructions that cause a processor to:
 determine an enablement of a first tool, for a conversion between a current block and a bitstream based on a rule, wherein the rule indicates that the first tool and a second tool are not both used by the current block; and   perform, based on the determining, a conversion between the current block and the bitstream;   wherein one of the first tool and the second tool is a decoder side motion vector derivation tool to derive a refinement of motion information related to the current block, and   
       the other of the first tool and the second tool comprises:
 a combined inter and intra prediction tool in which a prediction signal of a block is generated at least based on an intra prediction signal and an inter prediction signal. 
 
     
     
         20 . A non-transitory computer-readable recording medium storing a bitstream which is generated by a method performed by a video processing apparatus, wherein the method comprises:
 determining an enablement of a first tool, for a conversion between a current block and a bitstream based on a rule, wherein the rule indicates that the first tool and a second tool are not both used by the current block; and   generating the bitstream from the current block based on the determining;   wherein one of the first tool and the second tool is a decoder side motion vector derivation tool to derive a refinement of motion information related to the current block, and   
       the other of the first tool and the second tool comprises:
 a combined inter and intra prediction tool in which a prediction signal of a block is generated at least based on an intra prediction signal and an inter prediction signal.