Context for coding affine mode adaptive motion vector resolution
A method for video processing is provided. The method includes determining that a conversion between a current video block of a video and a coded representation of the current video block is based on a non-affine inter AMVR mode; and performing the conversion based on the determining, wherein the coded representation of the current video block is based on a context based coding, and wherein a context used for coding the current video block is modeled without using an affine AMVR mode information of a neighboring block during the conversion.
1. A method for video processing, comprising:
determining a coding mode for a current video block;
determining, for motion information of the current video block, a motion precision from a motion precision set including multiple motion precisions; and
performing a conversion between the current video block and a bitstream of a video comprising the current video block based on the determined coding mode and the determined motion precision;
wherein multiple syntax elements are selectively presented in the bitstream to indicate the motion precision in the motion precision set, wherein the multiple syntax elements include a first syntax element and a second syntax element, wherein the second syntax element is present in the bitstream in case that the first syntax element is present in the bitstream with a specific value,
wherein the second syntax element indicates a selection from 1/16-pel or 1-pel precision for a first mode;
wherein a first context is selected from multiple contexts for the first syntax element and a second context is selected from multiple contexts for the second syntax element based on whether the coding mode of the current video block is a first mode,
wherein in the first mode, control point motion vectors are derived and used to derive motion vectors of a sub-region split from the current video block, and
wherein the first context and the second context are selected without using coding information of a neighboring video block of the current block.
2. The method of claim 1 , wherein the coding information of the neighboring video block comprises a coding mode of the neighboring video block.
3. The method of claim 1 , wherein a variable controls two probability updating speeds for each context of the multiple contexts.
4. The method of claim 3 , wherein the two probability updating speeds include a first updating speed defined by (shiftIdx>>2)+2, shiftIdx indicating the variable.
5. The method of claim 3 , wherein the two probability updating speeds include a second updating speed defined by (shiftIdx & 3)+3+shift0, shift0 indicating a first updating speed and shiftIdx indicating the variable.
6. The method of claim 5 , wherein the second updating speed is between 2 and 5, inclusively.
7. The method of claim 1 , wherein the second syntax element indicates a selection from 1-pel or 4-pel precision for a normal inter mode.
8. The method of claim 1 , wherein the second syntax element is equal to 0, and the motion precision is ⅙-pel precision for a first mode, and wherein in the first mode, control point motion vectors are derived and further used to derive motion vectors of sub-region split from the current video block.
9. The method of claim 1 , wherein the second syntax element is equal to 1, and the motion precision is 1-pel precision for a first mode, and wherein in the first mode, control point motion vectors are derived and further used to derive motion vectors of sub-region split from the current video block.
10. The method of claim 1 , wherein the first syntax element is coded with a first context and the second syntax element is coded with a second context.
11. The method of claim 1 , wherein the performing of the conversion includes generating the bitstream based on the current video block.
12. The method of claim 1 , wherein the performing of the conversion includes generating the current video block from the bitstream.
13. 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 a coding mode for a current video block;
determine, for motion information of the current video block, a motion precision from a motion precision set including multiple motion precisions; and
perform a conversion between the current video block and a bitstream of a video comprising the current video block based on the determined coding mode and the determined motion precision;
wherein multiple syntax elements are selectively presented in the bitstream to indicate the motion precision in the motion precision set, wherein the multiple syntax elements include a first syntax element and a second syntax element, wherein the second syntax element is present in the bitstream in case that the first syntax element is present in the bitstream with a specific value,
wherein the second syntax element indicates a selection from 1/16-pel or 1-pel precision for a first mode;
wherein a first context is selected from multiple contexts for the first syntax element and a second context is selected from multiple contexts for the second syntax element based on whether the coding mode of the current video block is a first mode,
wherein in the first mode, control point motion vectors are derived and used to derive motion vectors of a sub-region split from the current video block, and
wherein the first context and the second context are selected without using coding information of a neighboring video block of the current block.
14. A non-transitory computer-readable storage medium storing instructions that cause a processor to:
determine a coding mode for a current video block;
determine, for motion information of the current video block, a motion precision from a motion precision set including multiple motion precisions; and
perform a conversion between the current video block and a bitstream of a video comprising the current video block based on the determined coding mode and the determined motion precision;
wherein multiple syntax elements are selectively presented in the bitstream to indicate the motion precision in the motion precision set, wherein the multiple syntax elements include a first syntax element and a second syntax element, wherein the second syntax element is present in the bitstream in case that the first syntax element is present in the bitstream with a specific value,
wherein the second syntax element indicates a selection from 1/16-pel or 1-pel precision for a first mode;
wherein a first context is selected from multiple contexts for the first syntax element and a second context is selected from multiple contexts for the second syntax element based on whether the coding mode of the current video block is a first mode,
wherein in the first mode, control point motion vectors are derived and used to derive motion vectors of a sub-region split from the current video block, and
wherein the first context and the second context are selected without using coding information of a neighboring video block of the current block.
15. 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 a coding mode for a current video block;
determining, for motion information of the current video block, a motion precision from a motion precision set including multiple motion precisions; and
generating the bitstream based on the determined coding mode and the determined motion precision;
wherein multiple syntax elements are selectively presented in the bitstream to indicate the motion precision in the motion precision set, wherein the multiple syntax elements include a first syntax element and a second syntax element, wherein the second syntax element is present in the bitstream in case that the first syntax element is present in the bitstream with a specific value,
wherein the second syntax element indicates a selection from 1/16-pel or 1-pel precision for a first mode;
wherein a first context is selected from multiple contexts for the first syntax element and a second context is selected from multiple contexts for the second syntax element based on whether the coding mode of the current video block is a first mode,
wherein in the first mode, control point motion vectors are derived and used to derive motion vectors of a sub-region split from the current video block, and
wherein the first context and the second context are selected without using coding information of a neighboring video block of the current block.
16. The apparatus of claim 13 , wherein a variable controls two probability updating speeds for each context of the multiple contexts.
17. The apparatus of claim 16 , wherein the two probability updating speeds include a first updating speed defined by (shiftIdx >>2)+2, shiftIdx indicating the variable.
18. The apparatus of claim 16 , wherein the two probability updating speeds include a second updating speed defined by (shiftIdx & 3)+3 +shift0, shift0 indicating a first updating speed and shiftIdx indicating the variable.
19. The non-transitory computer-readable storage medium of claim 14 , wherein a variable controls two probability updating speeds for each context of the multiple contexts.
20. The non-transitory computer-readable storage medium of claim 19 , wherein the two probability updating speeds include a first updating speed defined by (shiftIdx >>2)+2, shiftIdx indicating the variable.