Video decoding method and video decoder

1. A video decoding method, comprising:

receiving a bitstream comprising a to-be-entropy-decoded syntax element of a current block, wherein the to-be-entropy-decoded syntax element comprises a first syntax element or a second syntax element, wherein the first syntax element comprises a first flag indicating whether a subblock-based merge mode is used for the current block or the second syntax element comprises a second flag indicating whether an affine motion model-based motion compensation is used for the current block when a slice that comprises the current block is a predicted (P)-type slice or a bi-directional predicted (B)-type slice;

parsing the bitstream to obtain the to-be-entropy-decoded syntax element;

obtaining a first value of a first parameter for indicating whether a left neighboring block of the current block is available;

obtaining a second value of a second parameter for indicating whether an upper neighboring block of the current block is available;

obtaining a third value of a third flag or a fourth value of a fourth flag, wherein the third flag indicates whether the subblock-based merge mode is used for the left neighboring block or the fourth flag indicates whether the affine motion model-based motion compensation is used for the left neighboring block when a slice that comprises the left neighboring block is a P-type slice or a B-type slice;

obtaining a context index of the to-be-entropy-decoded syntax element based on the first value, the second value, and at least one of the third value or the fourth value;

performing entropy decoding on the to-be-entropy-decoded syntax element based on the context index to obtain a decoded syntax element corresponding to the to-be-entropy-decoded syntax element;

performing prediction processing on the current block based on the decoded syntax element to obtain a prediction block of the current block; and

obtaining a reconstructed image of the current block based on the prediction block.

2. The video decoding method of claim 1 , further comprising:

obtaining a fifth value of a fifth flag or a sixth value of a sixth flag, wherein the fifth flag indicates whether the subblock-based merge mode is used for the upper neighboring block or the sixth flag indicates whether the affine motion model-based motion compensation is used for the upper neighboring block when a slice that comprises the left neighboring block is a P-type slice or a B-type slice; and

further obtaining the context index of the to-be-entropy-decoded syntax element based on the fifth value or the sixth value.

3. The video decoding method of claim 2 , further comprising:

performing a first OR operation on the third value and the fourth value to obtain a seventh value;

performing a second OR operation on the fifth value and the sixth value to obtain an eighth value; and

further obtaining the context index of the to-be-entropy-decoded syntax element based on the seventh value and the eighth value.

4. The video decoding method of claim 3 , further comprising:

performing a first AND operation on the first value and the seventh value to obtain a ninth value;

performing a second AND operation on the second value and the eighth value to obtain a tenth value; and

further obtaining the context index of the to-be-entropy-decoded syntax element based on the ninth value and the tenth value.

5. The video decoding method of claim 4 , further comprising obtaining a sum of the ninth value and the tenth value, wherein the sum is the context index.

6. A video decoding device, comprising:

a non-transitory memory storage configured to store video data in a form of a bitstream, wherein the bitstream comprises a to-be-entropy-decoded syntax element of a current block, wherein the to-be-entropy-decoded syntax element comprises a first syntax element or a second syntax element, wherein the first syntax element comprises a first flag indicating whether a subblock-based merge mode is used for the current block or the second syntax element comprises a second flag indicating whether an affine motion model-based motion compensation is used for the current block when a slice that comprises the current block is a predicted (P)-type slice or a bi-directional predicted (B)-type slice; and

a video decoder coupled to the non-transitory memory storage and configured to:

parse the bitstream to obtain the to-be-entropy-decoded syntax element;

obtain a first value of a first parameter for indicating whether a left neighboring block of the current block is available;

obtain a second value of a second parameter for indicating whether an upper neighboring block of the current block is available;

obtain a third value of a third flag or a fourth value of a fourth flag, wherein the third flag indicates whether the subblock-based merge mode is used for the left neighboring block or the fourth flag indicates whether the affine motion model-based motion compensation is used for the left neighboring block when a slice that comprises the left neighboring block is a P-type slice or a B-type slice;

obtain a context index of the to-be-entropy-decoded syntax element based on the first value, the second value, and at least one of the third value or the fourth value;

perform entropy decoding on the to-be-entropy-decoded syntax element based on the context index to obtain a decoded syntax element corresponding to the to-be-entropy-decoded syntax element;

perform prediction processing on the current block based on the decoded syntax element to obtain a prediction block of the current block; and

obtain a reconstructed image of the current block based on the prediction block.

7. The video decoding device of claim 6 , wherein the video decoder is further configured to:

obtain a fifth value of a fifth flag or a sixth value of a sixth flag, wherein the fifth flag indicates whether the subblock-based merge mode is used for the upper neighboring block or the sixth flag indicates whether the affine motion model-based motion compensation is used for the upper neighboring block when a slice that comprises the left neighboring block is a P-type slice or a B-type slice; and

further obtain the context index of the to-be-entropy-decoded syntax element based the fifth value or the sixth value.

8. The video decoding device of claim 7 , wherein the video decoder is further configured to:

perform a first OR operation on the third value and the fourth value to obtain a seventh value;

perform a second OR operation on the fifth value and the sixth value to obtain an eighth value; and

further obtain the context index of the to-be-entropy-decoded syntax element based on the seventh value and the eighth value.

9. The video decoding device of claim 8 , wherein the video decoder is further configured to:

perform a first AND operation on the first value and the seventh value to obtain a ninth value;

perform a second AND operation on the second value and the eighth value to obtain a tenth value; and

further obtain the context index of the to-be-entropy-decoded syntax element based on the ninth value and the tenth value.

10. The video decoding device of claim 9 , wherein the video decoder is further configured to obtain a sum of the ninth value and the tenth value, wherein the sum is the context index.

11. The video decoding device of claim 6 , wherein the first syntax element and the second syntax element share a context model of the context index.

12. A video encoder comprising:

one or more memories configured to store programming instructions; and

one or more processors coupled to the one or more memories and configured to execute the programming instructions to cause the video encoder to:

generate a bitstream, wherein the bitstream comprises a first to-be-entropy-decoded syntax element of a current block and a second to-be-entropy-decoded syntax element of a left neighboring block of the current block, wherein the first to-be-entropy-decoded syntax element comprises a first syntax element or a second syntax element, wherein the first syntax element comprises a first flag indicating whether a subblock-based merge mode is used for the current block or the second syntax element comprises a second flag indicating whether an affine motion model-based motion compensation is used for the current block when a slice that comprises the current block is a predicted (P)-type slice or a bi-directional predicted (B)-type slice, wherein the second to-be-entropy-decoded syntax element comprises a third syntax element or a fourth syntax element, wherein the third syntax element comprises a third flag indicating whether the subblock-based merge mode is used for the left neighboring block or the fourth syntax element comprises a fourth flag indicates whether the affine motion model-based motion compensation is used for the left neighboring block when a slice that comprises the left neighboring block is a P-type slice or a B-type slice, wherein at least one of a third value of the third flag or a fourth value of the fourth flag are used to obtain a context index of the first to-be-entropy-decoded syntax element, wherein the context index is used to perform entropy decoding on the first to-be-entropy-decoded syntax element to obtain a decoded syntax element corresponding to the first to-be-entropy-decoded syntax element, wherein the decoded syntax element is used to perform prediction processing on the current block to obtain a prediction block of the current block, and wherein the prediction block is used to obtain a reconstructed image of the current block; and

transmit the bitstream to a video decoding device.

13. The video encoder of claim 12 , wherein the bitstream further comprises a third to-be-entropy-decoded syntax element of a upper neighboring block of the current block, wherein the third to-be-entropy-decoded syntax element comprises a fifth syntax element or a sixth syntax element, wherein the fifth syntax element comprises a fifth flag indicating whether the subblock-based merge mode is used for the upper neighboring block or the sixth syntax element comprises a sixth flag indicates whether the affine motion model-based motion compensation is used for the upper neighboring block when a slice that comprises the left neighboring block is a P-type slice or a B-type slice, and wherein at least one of a fifth value of the fifth flag or a sixth value of the sixth flag are used to obtain a context index of the first to-be-entropy-decoded syntax element.

14. The video encoder of claim 12 , wherein a context model corresponding to the first syntax element is based on a preset context model set or a context model corresponding to the second syntax element is based on the preset context model set.

15. The video encoder of claim 14 , wherein the first syntax element and the second syntax element share the context model.

16. The video encoder of claim 12 , wherein the one or more processors are further configured to execute the programming instructions to cause the video encoder to further transmit the bitstream to a video decoder.

17. A non-transitory storage medium storing an encoded bitstream for video signals, the encoded bitstream comprising:

a first to-be-entropy-decoded syntax element of a current block, wherein the first to-be-entropy-decoded syntax element comprises a first syntax element or a second syntax element, wherein the first syntax element comprises a first flag indicating whether a subblock-based merge mode is used for the current block or the second syntax element comprises a second flag indicating whether an affine motion model-based motion compensation is used for the current block when a slice that comprises the current block is a predicted (P)-type slice or a bi-directional predicted (B)-type slice; and

a second to-be-entropy-decoded syntax element of a left neighboring block of the current block,

wherein the second to-be-entropy-decoded syntax element comprises a third syntax element or a fourth syntax element,

wherein the third syntax element comprises a third flag indicating whether the subblock-based merge mode is used for the left neighboring block or the fourth syntax element comprises a fourth flag indicates whether the affine motion model-based motion compensation is used for the left neighboring block when a slice that comprises the left neighboring block is a P-type slice or a B-type slice,

wherein at least one of a third value of the third flag or a fourth value of the fourth flag are used to obtain a context index of the first to-be-entropy-decoded syntax element,

wherein the context index is used to perform entropy decoding on the first to-be-entropy-decoded syntax element to obtain a decoded syntax element corresponding to the first to-be-entropy-decoded syntax element,

wherein the decoded syntax element is used to perform prediction processing on the current block to obtain a prediction block of the current block, and

wherein the prediction block is used to obtain a reconstructed image of the current block.

18. The non-transitory storage medium of claim 17 , wherein the encoded bitstream further comprises a third to-be-entropy-decoded syntax element of a upper neighboring block of the current block, wherein the third to-be-entropy-decoded syntax element comprises a fifth syntax element or a sixth syntax element, wherein the fifth syntax element comprises a fifth flag indicating whether the subblock-based merge mode is used for the upper neighboring block or the sixth syntax element comprises a sixth flag indicates whether the affine motion model-based motion compensation is used for the upper neighboring block when a slice that comprises the left neighboring block is a P-type slice or a B-type slice, and wherein at least one of a fifth value of the fifth flag or a sixth value of the sixth flag are used to obtain a context index of the first to-be-entropy-decoded syntax element.

19. The non-transitory storage medium of claim 17 , wherein a context model corresponding to the first syntax element is based on a preset context model set or a context model corresponding to the second syntax element is based on the preset context model set.

20. The non-transitory storage medium of claim 19 , wherein the first syntax element and the second syntax element share the context model.