Video decoding method and video decoder

A video decoder, comprising:

• an entropy decoding unit, configured to
• parse coding tree split information to obtain a current node;
• determine, based on a depth N of the current node, coordinates of an upper-left corner of a region covered by a current quantization group;
• obtain a quantization parameter (QP) delta of a current coding unit (CU) that covers the coordinates of the upper-left corner of the region covered by the current quantization group;
• and
• determine a luminance QP of the current CU based on the QP delta of the current CU;
• an inverse quantization unit, configured to obtain a dequantized coefficient of the current CU based on the luminance QP of the current CU;
• an inverse transform processing unit, configured to obtain a reconstructed residual block of the current CU based on the dequantized coefficient of the current CU;
• and
• a reconstruction unit, configured to obtain a reconstructed picture of the current CU based on the reconstructed residual block of the current CU;
• wherein the coordinates of the upper-left corner of the region covered by the current quantization group are coordinates of an upper-left corner of a region covered by the current node,
• if the depth N of the current node is equal to a second threshold T2 minus 1, and a split mode of the current node is a ternary split mode, or
• if the depth N of the current node is equal to a second threshold T2, and the split mode of the current node is a binary split mode or a quadtree split mode, or
• if the depth N of the current node is equal to a third threshold T3 minus 1, and a split mode of the current node is a ternary split mode or a quadtree split mode, or
• if the depth N of the current node is equal to a third threshold T3, and the split mode of the current node is a binary split mode.

A non-transitory computer-readable storage medium storing computer instructions, that when executed by one or more processors, cause the one or more processors to perform the operations of:

• parsing coding tree split information to obtain a current node;
• determining, based on a depth N of the current node, coordinates of an upper-left corner of a region covered by a current quantization group;
• obtaining a quantization parameter (QP) delta of a current coding unit (CU) in the region covered by the current quantization group;
• and
• obtaining a reconstructed picture of the current CU based on the QP delta of the current CU;
• wherein the coordinates of the upper-left corner of the region covered by the current quantization group are coordinates of an upper-left corner of a region covered by the current node,
• if the depth N of the current node is equal to a second threshold T2 minus 1, and a split mode of the current node is a ternary split mode, or
• if the depth N of the current node is equal to a second threshold T2, and a split mode of the current node is a binary split mode or a quadtree split mode, or
• if the depth N of the current node is equal to a third threshold T3 minus 1, and a split mode of the current node is a ternary split mode or a quadtree split mode, or
• if the depth N of the current node is equal to a third threshold T3, and a split mode of the current node is a binary split mode.

A non-transitory computer-readable storage medium comprising a bitstream decoded by performing the operations of:

• parsing, based on the bitstream, coding tree split information to obtain a current node;
• determining, based on a depth N of the current node, coordinates of an upper-left corner of a region covered by a current quantization group;
• obtaining a quantization parameter (QP) delta of a current coding unit (CU) in the region covered by the current quantization group;
• and
• obtaining a reconstructed picture of the current CU based on the QP delta of the current CU;
• wherein the coordinates of the upper-left corner of the region covered by the current quantization group are coordinates of an upper-left corner of a region covered by the current node,
• if the depth N of the current node is equal to a second threshold T2 minus 1, and a split mode of the current node is a ternary split mode, or
• if the depth N of the current node is equal to a second threshold T2, and a split mode of the current node is a binary split mode or a quadtree split mode, or
• if the depth N of the current node is equal to a third threshold T3 minus 1, and a split mode of the current node is a ternary split mode or a quadtree split mode, or
• if the depth N of the current node is equal to a third threshold T3, and a split mode of the current node is a binary split mode.