Coding and decoding methods, coder and decoder, and storage medium

A decoding method, comprising:

• acquiring coded data of a current block;
• determining that a height and a width of the current block are both less than or equal to a preset threshold and the current block is a luma block;
• acquiring a transform pair index corresponding to the current block from the coded data, wherein in the case that the transform pair index comprises five index values, a transform pair mapped by the transform pair index is (DCT2, DCT2) in response to the index value of the transform pair index being a first index value;
• the transform pair mapped by the transform pair index is (DST7, DST7) in response to the index value of the transform pair index being a second index value;
• the transform pair mapped by the transform pair index is (DCT8, DST7) in response to the index value of the transform pair index being a third index value;
• the transform pair as mapped by the transform pair index is (DST7, DCT8) in response to the index value of the transform pair index being a fourth index value;
• and the transform pair mapped by the transform pair index is (DCT8, DCT8) in response to the index value of the transform pair index being a fifth index value;
• wherein a binarized codeword corresponding to the transform pair index occupies at most four bits and a first bit of the binarized codeword corresponding to the transform pair index is intended to indicate whether the transform pair mapped by the first index value is selected, wherein the transform pair (DCT2, DCT2) mapped by the first index value is selected in response to a value of the first bit being a first value, and the transform pair mapped by one of the remaining index values is selected in response to the value of the first bit being a second value;
• and wherein the first bit of the binarized codeword corresponding to the transform pair index is decoded by context-based adaptive binary arithmetic coding based on one context model;
• and
• determining the transform pair corresponding to the current block based on the transform pair index, wherein the transform pair comprises a horizontal transform kernel and a vertical transform kernel.

A coding method, comprising:

• determining that a height and a width of a current block are both less than or equal to a preset threshold and the current block is a luma block;
• determining a transform pair corresponding to the current block and a transform pair index corresponding to the current block, wherein in the case that the transform pair index comprises five index values, the transform pair mapped by the transform pair index is (DCT2, DCT2) in response to the index value of the transform pair index being a first index value;
• the transform pair mapped by the transform pair index is (DST7, DST7) in response to the index value of the transform pair index being a second index value;
• the transform pair mapped by the transform pair index is (DCT8, DST7) in response to the index value of the transform pair index being a third index value;
• the transform pair mapped by the transform pair index is (DST7, DCT8) in response to the index value of the transform pair index being a fourth index value;
• and the transform pair mapped by the transform pair index is (DCT8, DCT8) in response to the index value of the transform pair index being a fifth index value;
• and wherein a binarized codeword corresponding to the transform pair index occupies at most four bits and a first bit of the binarized codeword corresponding to the transform pair index is intended to indicate whether the transform pair mapped by the first index value is selected, wherein the transform pair (DCT2, DCT2) mapped by the first index value is selected in response to a value of the first bit being a first value, and the transform pair mapped by one of the remaining index values is selected in response to the value of the first bit being a second value;
• and
• coding the transform pair index by subjecting the first bit of the binarized codeword corresponding to the transform pair index to context-based adaptive binary arithmetic coding based on one context model, and adding the transform pair index as coded to coded data of the current block.

The coding method according to 37, wherein:

• the first bit of the binarized codeword is 0 in response to the transform pair corresponding to the current block being (DCT2, DCT2);
• the first bit of the binarized codeword is 1 and the second bit is 0 in response to the transform pair corresponding to the current block being (DST7, DST7);
• the first bit of the binarized codeword is 1, the second bit is 1, and the third bit is 0 in response to the transform pair corresponding to the current block being (DCT8, DST7);
• the first bit of the binarized codeword is 1, the second bit is 1, the third bit is 1, and the fourth bit is 0 in response to the transform pair corresponding to the current block being (DST7, DCT8);
• and
• the first bit of the binarized codeword is 1, the second bit is 1, the third bit is 1, and the fourth bit is 1 in response to the transform pair corresponding to the current block being (DCT8, DCT8).

A decoder, comprising a processor and a memory storing at least one instruction executable by the processor;

• wherein the processor, when loading and executing the at least one instruction, is caused to perform a method comprising:
• acquiring coded data of a current block;
• determining that a height and a width of the current block are both less than or equal to a preset threshold and the current block is a luma block;
• acquiring a transform pair index corresponding to the current block from the coded data, wherein in the case that the transform pair index comprises five index values, a transform pair mapped by the transform pair index is (DCT2, DCT2) in response to the index value of the transform pair index being a first index value;
• the transform pair mapped by the transform pair index is (DST7, DST7) in response to the index value of the transform pair index being a second index value;
• the transform pair mapped by the transform pair index is (DCT8, DST7) in response to the index value of the transform pair index being a third index value;
• the transform pair mapped by the transform pair index is (DST7, DCT8) in response to the index value of the transform pair index being a fourth index value;
• and the transform pair mapped by the transform pair index is (DCT8, DCT8) in response to the index value of the transform pair index being a fifth index value;
• and wherein a binarized codeword corresponding to the transform pair index occupies at most four bits, and a first bit of the binarized codeword corresponding to the transform pair index is intended to indicate whether the transform pair mapped by the first index value is selected, wherein the transform pair (DCT2, DCT2) mapped by the first index value is selected in response to a value of the first bit being a first value, and the transform pair mapped by one of the remaining index values is selected in response to the value of the first bit being a second value;
• and wherein the first bit of the binarized codeword corresponding to the transform pair index is decoded by context-based adaptive binary arithmetic coding based on one context model;
• and
• determining the transform pair corresponding to the current block based on the transform pair index, wherein the transform pair comprises a horizontal transform kernel and a vertical transform kernel.

A coder, comprising a processor and a memory storing at least one instruction executable by the processor;

• wherein the processor, when loading and executing the at least one instruction, is caused to perform a method comprising:
• determining that a height and a width of a current block are both less than or equal to a preset threshold and the current block is a luma block;
• determining a transform pair corresponding to the current block and a transform pair index corresponding to the current block, wherein in the case that the transform pair index comprises five index values, the transform pair mapped by the transform pair index is (DCT2, DCT2) in response to the index value of the transform pair index being a first index value;
• the transform pair mapped by the transform pair index is (DST7, DST7) in response to the index value of the transform pair index being a second index value;
• the transform pair mapped by the transform pair index is (DCT8, DST7) in response to the index value of the transform pair index being a third index value;
• the transform pair mapped by the transform pair index is (DST7, DCT8) in response to the index value of the transform pair index being a fourth index value;
• and the transform pair mapped by the transform pair index is (DCT8, DCT8) in response to the index value of the transform pair index being a fifth index value;
• and wherein a binarized codeword corresponding to the transform pair index occupies at most four bits and a first bit of the binarized codeword corresponding to the transform pair index is intended to indicate whether the transform pair mapped by the first index value is selected, wherein the transform pair (DCT2, DCT2) mapped by the first index value is selected in response to a value of the first bit being a first value, and the transform pair mapped by one of the remaining index values is selected in response to the value of the first bit being a second value;
• and
• coding the transform pair index by subjecting the first bit of the binarized codeword corresponding to the transform pair index to context-based adaptive binary arithmetic coding based on one context model, and adding the transform pair index as coded to coded data of the current block.

A non-transitory computer-readable storage medium, storing at least one instruction executable by a processor;

• wherein the at least one instruction, when loaded and executed by the processor, causes the processor to perform a method comprising:
• acquiring coded data of a current block;
• determining that a height and a width of the current block are both less than or equal to a preset threshold and the current block is a luma block;
• acquiring a transform pair index corresponding to the current block from the coded data, wherein in the case that the transform pair index comprises five index values, a transform pair mapped by the transform pair index is (DCT2, DCT2) in response to the index value of the transform pair index being a first index value;
• the transform pair mapped by the transform pair index is (DST7, DST7) in response to the index value of the transform pair index being a second index value;
• the transform pair mapped by the transform pair index is (DCT8, DST7) in response to the index value of the transform pair index being a third index value;
• the transform pair as mapped by the transform pair index is (DST7, DCT8) in response to the index value of the transform pair index being a fourth index value;
• and the transform pair mapped by the transform pair index is (DCT8, DCT8) in response to the index value of the transform pair index being a fifth index value;
• wherein a binarized codeword corresponding to the transform pair index occupies at most four bits and a first bit of the binarized codeword corresponding to the transform pair index is intended to indicate whether the transform pair mapped by the first index value is selected, wherein the transform pair (DCT2, DCT2) mapped by the first index value is selected in response to a value of the first bit being a first value, and the transform pair mapped by one of the remaining index values is selected in response to the value of the first bit being a second value;
• and wherein the first bit of the binarized codeword corresponding to the transform pair index is decoded by context-based adaptive binary arithmetic coding based on one context model;
• and
• determining the transform pair corresponding to the current block based on the transform pair index, wherein the transform pair comprises a horizontal transform kernel and a vertical transform kernel.

A non-transitory computer-readable storage medium, storing at least one instruction executable by a processor;

• wherein the at least one instruction, when loaded and executed by the processor, causes the processor to perform a method comprising:
• determining that a height and a width of a current block are both less than or equal to a preset threshold and the current block is a luma block;
• determining a transform pair corresponding to the current block and a transform pair index corresponding to the current block, wherein in the case that the transform pair index comprises five index values, the transform pair mapped by the transform pair index is (DCT2, DCT2) in response to the index value of the transform pair index being a first index value;
• the transform pair mapped by the transform pair index is (DST7, DST7) in response to the index value of the transform pair index being a second index value;
• the transform pair mapped by the transform pair index is (DCT8, DST7) in response to the index value of the transform pair index being a third index value;
• the transform pair mapped by the transform pair index is (DST7, DCT8) in response to the index value of the transform pair index being a fourth index value;
• and the transform pair mapped by the transform pair index is (DCT8, DCT8) in response to the index value of the transform pair index being a fifth index value;
• and wherein a binarized codeword corresponding to the transform pair index occupies at most four bits and a first bit of the binarized codeword corresponding to the transform pair index is intended to indicate whether the transform pair mapped by the first index value is selected, wherein the transform pair (DCT2, DCT2) mapped by the first index value is selected in response to a value of the first bit being a first value, and the transform pair mapped by one of the remaining index values is selected in response to the value of the first bit being a second value;
• and
• coding the transform pair index by subjecting the first bit of the binarized codeword corresponding to the transform pair index to context-based adaptive binary arithmetic coding based on one context model, and adding the transform pair index as coded to coded data of the current block.