Merge with MVD for affine
The method relates to harmonization between affine mode and other inter coding tools mode. The method for video processing includes acquiring, during a conversion between a current block and a bitstream representation of the current block, an indication of the current block, where the indication indicates whether a merged affine model of the current block should be modified, and performing, at least based on the indication, the conversion between the current block and the bitstream representation of the current block.
1. A method of processing video data, comprising:
determining, for a conversion between a current block of a video and a bitstream of the video, whether an indication of the current block is included in the bitstream according to a rule, wherein the indication indicates whether a merged affine model of the current block should be modified, and the rule specific that the indication is not included in the bitstream in a case that a width of the current block is smaller than a first predetermined value or a height of the current block is smaller than a second predetermined value; and
performing the conversion at least based on the indication;
wherein modifying the merged affine model comprises at least one of:
modifying at least one control point motion vector (CPMV) of the merged affine model;
modifying at least one affine parameter of the merged affine model; and
switching the merged affine model between four affine parameters and six affine parameters, and
wherein at least one index is included in the bitstream in a case that the indication indicates that the merged affine model of the current block should be modified.
2. The method of claim 1 , wherein the first predetermined value is equal to 16.
3. The method of claim 1 , wherein the second predetermined value is equal to 16.
4. The method of claim 1 , wherein the indication is coded with context model.
5. The method of claim 1 , wherein the at least one index comprises at least one of a direction index and a distance index.
6. The method of claim 5 , wherein the direction index is binarized as a fixed length code.
7. The method of claim 6 , wherein a first K bins of the fixed length code are coded with a context model.
8. The method of claim 7 , wherein the K is equal to 2.
9. The method of claim 5 , wherein the distance index is binarized as a truncated unary code.
10. The method of claim 9 , wherein a first K bins of the truncated unary code are coded with a context model and a remaining bins of the truncated unary code are bypass coded, and the K is equal to 1.
11. The method of claim 1 , wherein a control point motion vector (CPMV) of the current block is added with an offset in a case that the indication is included in the bitstream.
12. The method of claim 11 , wherein at least one modification index for deriving the offset is included in the bitstream in a case that the indication indicates that the merged affine model of the current block should be modified.
13. The method of claim 12 , wherein M modification indexes are included in the bitstream, and wherein the M modification indexes are representing M offsets for M CPMVs respectively, and M is an integer.
14. The method of claim 11 , wherein the offset is derived based on a lookup table.
15. The method of claim 1 , wherein the conversion includes encoding the current block into the bitstream.
16. The method of claim 1 , wherein the conversion includes decoding the current block from the bitstream.
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, for a conversion between a current block of a video and a bitstream of the video, whether an indication of the current block is included in the bitstream according to a rule, wherein the indication indicates whether a merged affine model of the current block should be modified, and the rule specific that the indication is not included in the bitstream in a case that a width of the current block is smaller than a first predetermined value or a height of the current block is smaller than a second predetermined value; and
perform the conversion at least based on the indication;
wherein modify the merged affine model comprises at least one of:
modify at least one control point motion vector (CPMV) of the merged affine model;
modifying at least one affine parameter of the merged affine model; and
switch the merged affine model between four affine parameters and six affine parameters, and
wherein at least one index is included in the bitstream in a case that the indication indicates that the merged affine model of the current block should be modified.
18. A non-transitory computer-readable storage medium storing instructions that cause a processor to:
determine, for a conversion between a current block of a video and a bitstream of the video, whether an indication of the current block is included in the bitstream according to a rule, wherein the indication indicates whether a merged affine model of the current block should be modified, and the rule specific that the indication is not included in the bitstream in a case that a width of the current block is smaller than a first predetermined value or a height of the current block is smaller than a second predetermined value; and
perform the conversion at least based on the indication;
wherein modify the merged affine model comprises at least one of:
modify at least one control point motion vector (CPMV) of the merged affine model;
modifying at least one affine parameter of the merged affine model; and
switch the merged affine model between four affine parameters and six affine parameters, and
wherein at least one index is included in the bitstream in a case that the indication indicates that the merged affine model of the current block should be modified.
19. A non-transitory computer-readable recording medium storing a bitstream of a video which is generated by a method performed by a video processing apparatus, wherein the method comprises:
determining, whether an indication of a current block of the video is included in the bitstream according to a rule, wherein the indication indicates whether a merged affine model of the current block should be modified, and the rule specific that the indication is not included in the bitstream in a case that a width of the current block is smaller than a first predetermined value or a height of the current block is smaller than a second predetermined value; and
generating the bitstream based on the indication;
wherein modifying the merged affine model comprises at least one of:
modifying at least one control point motion vector (CPMV) of the merged affine model;
modifying at least one affine parameter of the merged affine model; and
switching the merged affine model between four affine parameters and six affine parameters, and
wherein at least one index is included in the bitstream in a case that the indication indicates that the merged affine model of the current block should be modified.