In one method, the current block is partitioned into multiple final sub-blocks using one or more stages of sub-tree partition comprising ternary tree partition and at least one other-type partition, where ternary partition tree is excluded from the sub-tree partition if a current sub-tree depth associated with a current sub-block is greater than a first threshold and the first threshold is an integer greater than or equal to 1. In another method, if a test condition is satisfied, the current block is encoded or decoded using a current Inter mode selected from a modified group of Inter tools, where the modified group of Inter tools is derived from an initial group of Inter tools by removing one or more first Inter tools from the initial group of Inter tools, replacing one or more second Inter tools with one or more complexity-reduced Inter tools, or both.