Picture data encoding method and apparatus and picture data decoding method and apparatus

A picture data encoding method, wherein the encoding method comprises:

• determining a coding tree unit (“CTU”) corresponding to a to-be-encoded picture block;
• splitting the CTU in a node split mode corresponding to a first-level coding tree, to obtain a leaf node of the first-level coding tree, wherein a root node of the first-level coding tree corresponds to the CTU;
• determining a candidate-split-mode set corresponding to a first node of a second-level coding tree, wherein the candidate-split-mode set corresponding to the first node meets a first preset split condition, the first preset split condition is used to indicate whether to restrict the first node to be split according to a target split mode, a root node of the second-level coding tree is a leaf node of the first-level coding tree, and the target split mode comprises at least one of horizontal binary split, horizontal ternary split, vertical binary split, and vertical ternary split;
• and
• encoding a coding unit (“CU”) which is the first node or a sub-node obtained by splitting the first node by a split mode in the candidate-split-mode set, to obtain a coding-unit bitstream corresponding to the coding unit.

A decoder device, comprising:

• an obtaining module, configured to obtain a bitstream comprising picture data;
• a parsing module, configured to:
• parse the bitstream obtained by the obtaining module, to obtain node split mode information of a first-level coding tree, wherein a root node of the first-level coding tree corresponds to one coding tree unit, and at least one leaf node of the first-level coding tree is defined by using the root node of the first-level coding tree and a node split mode corresponding to the node split mode information of the first-level coding tree;
• parse the bitstream to obtain node split mode information of a second-level coding tree, wherein the node split mode information of the second-level coding tree indicates a split mode corresponding to a first node of the second-level coding tree that is also a leaf node of the first-level coding tree, the split mode corresponding to the first node is one mode in a candidate-split-mode set corresponding to the first node, the candidate-split-mode set corresponding to the first node is determined according to a first preset split condition, the first preset split condition is used to indicate whether to restrict the candidate-split-mode set such that the first node is split according to a target split mode, the target split mode comprises at least one of a horizontal binary split, horizontal ternary split, vertical binary split, and vertical ternary split, and a root node of the second-level coding tree is a leaf node of the first-level coding tree;
• a decoding and reconstructing module, configured to decode and reconstruct the coding unit (“CU”) which is the first node or a sub-node obtained by splitting the first node by the split mode corresponding to the first node, based on encoding information of the first node obtained by the parsing module, to obtain a picture corresponding to the picture data.

An encoder device, comprising:

• a determining module, configured to determine a coding tree unit (“CTU”) corresponding to a to-be-encoded picture block;
• a splitting module, configured to split, in a node split mode corresponding to a first-level coding tree, the CTU determined by the determining module, to obtain a leaf node of the first-level coding tree, wherein a root node of the first-level coding tree corresponds to the CTU;
• wherein
• the determining module is further configured to determine a candidate-split-mode set corresponding to a first node of a second-level coding tree that is also a leaf node of the first-level-coding tree, wherein the candidate-split-mode set corresponding to the first node meets a first preset split condition, the first preset split condition is used to indicate whether to restrict the first node to be split according to a target split mode, a root node of the second-level coding tree is a leaf node of the first-level coding tree, and the target split mode comprises at least one of a horizontal binary split, horizontal ternary split, vertical binary split, and vertical ternary split;
• and
• an encoding module, configured to:
• encode a coding unit (“CU”) which is the first node or a sub-node obtained by splitting the first node by a split mode in the candidate-split-mode set, to obtain a coding-unit bitstream corresponding to the coding unit.