Video encoding and decoding methods and apparatuses, device, and storage medium

1. A video decoding method, comprising:

decoding intra-frame prediction mode information corresponding to a current decoding unit;

decoding first identification information corresponding to the current decoding unit when the decoded intra-frame prediction mode information indicates that a block differential pulse code modulation (BDPCM) mode is applied to the current decoding unit, and all color components of the current decoding unit use the BDPCM mode, the first identification information being a single syntax element and indicating whether a transform block (TB) corresponding to the current decoding unit includes a non-zero transform coefficient;

when a coding tree type corresponding to the current decoding unit is single tree and the single syntax element indicates that at least one of a luma TB, a first chroma TB, and a second chroma TB of the TB corresponding to the current decoding unit includes the non-zero transform coefficient, determining a residual block corresponding to the current decoding unit as a non-zero residual block;

when the coding tree type corresponding to the current decoding unit is dual tree luma and the single syntax element indicates that the luma TB corresponding to the current decoding unit includes the non-zero transform coefficient, determining the residual block corresponding to the current decoding unit as the non-zero residual block;

when the coding tree type corresponding to the current decoding unit is dual tree chroma and the single syntax element indicates that at least one of a first chroma TB and a second chroma TB that correspond to the current decoding unit includes the non-zero transform coefficient, determining the residual block corresponding to the current decoding unit as the non-zero residual block; and

reconstructing the current decoding unit according to the residual block and a prediction block corresponding to the current decoding unit.

2. The method according to claim 1 , wherein the first identification information is present in a coding unit (CU) syntax structure.

3. The method according to claim 2 , wherein the first identification information is cu_cbf,

a value of cu_cbf being equal to one indicating that the TB corresponding to the current decoding unit comprises the non-zero transform coefficient; and

the value of cu_cbf being equal to zero indicating that the TB corresponding to the current decoding unit does not comprise any non-zero transform coefficients.

4. The method according to claim 1 , wherein the first identification information is present in a transform unit (TU) syntax structure.

5. The method according to claim 4 , wherein the first identification information is tu_cbf_chroma[xC][yC],

a value of tu_cbf_chroma[xC][yC] being equal to one indicating that the at least one of the first chroma TB and the second chroma TB that correspond to the current decoding unit comprises the non-zero transform coefficient; and

the value of tu_cbf_chroma[xC][yC] being equal to zero indicating that neither of the first chroma TB and the second chroma TB that correspond to the current decoding unit comprises the non-zero transform coefficient.

6. The method according to claim 5 , further comprising:

decoding tu_cbf_chroma[xC][yC] by using an entropy decoding scheme of context-based adaptive binary arithmetic coding (CABAC).

7. The method according to claim 1 , further comprising:

when the current decoding unit meets a predefined condition, decoding the first identification information corresponding to the current decoding unit,

wherein the predefined condition comprises determining, according to the coding tree type corresponding to the current decoding unit, that all the color components of the current decoding unit use the BDPCM mode.

8. The method according to claim 7 , wherein the first identification information is present in a syntax structure of a CU, and

the predefined condition comprises (i) the BDPCM mode is applied to a luma component of the current decoding unit, and (ii) at least one of

the coding tree type corresponding to the current decoding unit is the dual tree luma; or

the coding tree type corresponding to the current decoding unit is the single tree and a value of ChromaArray Type is not equal to three, the value of the ChromaArray Type being equal to three indicating that three color components of the current decoding unit are not separately decoded and a chroma format is 4:4:4.

9. The method according to claim 7 , wherein the first identification information is present in a syntax structure of a CU, and

the predefined condition comprises the BDPCM mode is applied to chroma components of the current decoding unit, and the coding tree type corresponding to the current decoding unit is the dual tree chroma.

10. The method according to claim 9 , wherein after the decoding the first identification information corresponding to the current decoding unit, the method further comprises:

decoding second identification information corresponding to the current decoding unit when the first identification information indicates that the TB corresponding to the current decoding unit comprises the non-zero transform coefficient, the second identification information being used for indicating whether the first chroma TB corresponding to the current decoding unit comprises the non-zero transform coefficient; and

decoding third identification information corresponding to the current decoding unit when at least one condition in a first condition set is met, the third identification information being used for indicating whether the second chroma TB corresponding to the current decoding unit comprises the non-zero transform coefficient.

11. The method according to claim 10 , wherein the first condition set comprises:

the BDPCM mode is not applied to the chroma components of the current decoding unit;

the coding tree type corresponding to the current decoding unit is not the dual tree chroma; and

a value of the second identification information indicates that the first chroma TB corresponding to the current decoding unit does not comprise any non-zero transform coefficients.

12. The method according to claim 7 , wherein the first identification information is present in a CU syntax structure or a TU syntax structure, and

the predefined condition comprises the BDPCM mode is applied to all the color components of the current decoding unit, and the coding tree type corresponding to the current decoding unit is the single tree.

13. The method according to claim 12 , wherein after the decoding the first identification information corresponding to the current decoding unit, the method further comprises:

decoding second identification information corresponding to the current decoding unit when the first identification information indicates that at least one of the first chroma TB and the second chroma TB that correspond to the current decoding unit comprises the non-zero transform coefficient, the second identification information being used for indicating whether the first chroma TB corresponding to the current decoding unit comprises the non-zero transform coefficient; and

decoding third identification information corresponding to the current decoding unit when at least one condition in a second condition set is met, the third identification information being used for indicating whether the second chroma TB corresponding to the current decoding unit comprises the non-zero transform coefficient.

14. The method according to claim 13 , wherein the second condition set comprises:

the coding tree type corresponding to the current decoding unit is not the single tree;

a value of the second identification information indicates that the first chroma TB corresponding to the current decoding unit comprises the non-zero transform coefficient; and

the BDPCM mode is not applied to all the color components of the current decoding unit.

15. A video encoding method, comprising:

obtaining a current coding unit (CU);

calculating a residual block corresponding to the current CU according to the current CU and a prediction block corresponding to the current CU; and

encoding first identification information corresponding to the current CU when all color components of the current CU use a block differential pulse code modulation (BDPCM) mode, wherein

the first identification information indicates that, when a coding tree type corresponding to the current CU is single tree, at least one of a luma transform block (TB), a first chroma TB, and a second chroma TB corresponding to the current CU includes a non-zero transform coefficient,

the first identification information indicates that, when the coding tree type corresponding to the current CU is dual tree luma, the luma TB corresponding to the current CU includes the non-zero transform coefficient, and

the first identification information indicates that, when the coding tree type corresponding to the current CU is dual tree chroma, at least one of the first chroma TB and the second chroma TB corresponding to the current CU includes the non-zero transform coefficient.

16. A video decoding apparatus, comprising:

processing circuitry configured to

decode intra-frame prediction mode information corresponding to a current decoding unit;

decode first identification information corresponding to the current decoding unit when the decoded intra-frame prediction mode information indicates that a block differential pulse code modulation (BDPCM) mode is applied to the current decoding unit, and all color components of the current decoding unit use the BDPCM mode, the first identification information being a single syntax element and indicating whether a transform block (TB) corresponding to the current decoding unit comprises a non-zero transform coefficient;

when a coding tree type corresponding to the current decoding unit is single tree and the single syntax element indicates that at least one of a luma TB, a first chroma TB, and a second chroma TB of the TB corresponding to the current decoding unit includes the non-zero transform coefficient, determine a residual block corresponding to the current decoding unit as a non-zero residual block;

when the coding tree type corresponding to the current decoding unit is dual tree luma and the single syntax element indicates that the luma TB corresponding to the current decoding unit includes the non-zero transform coefficient, determine the residual block corresponding to the current decoding unit as the non-zero residual block;

when the coding tree type corresponding to the current decoding unit is dual tree chroma and the single syntax element indicates that at least one of a first chroma TB and a second chroma TB that correspond to the current decoding unit includes the non-zero transform coefficient, determine the residual block corresponding to the current decoding unit as the non-zero residual block; and

reconstruct the current decoding unit according to the residual block and a prediction block corresponding to the current decoding unit.

17. A computer device, comprising processing circuitry and a memory, the memory storing at least one instruction, at least one program, a code set, or an instruction set, the at least one instruction, the at least one program, the code set, or the instruction set being loaded and executed by the processing circuitry to implement the method according to claim 1 .

18. A non-transitory computer-readable storage medium, storing at least one instruction, at least one program, a code set, or an instruction set, the at least one instruction, the at least one program, the code set, or the instruction set being loaded and executed by processing circuitry to implement the method according to claim 1 .

19. The method according to claim 1 , wherein the first identification information is a flag,

a value of the flag being equal to one indicating that the TB corresponding to the current decoding unit comprises the non-zero transform coefficient; and

the value of the flag being equal to zero indicating that the TB corresponding to the current decoding unit does not comprise any non-zero transform coefficients.