One example for the quadtree with nested multi-type tree coding block structure of block partition for one CTB is shown in FIG. 12. In more detail, FIG. 12 shows that the CTB 1200 is quadtree split into four square partitions 1202, 1204, 1206, and 1208. Decision to further use the multi-type tree structure of FIG. 11 for splitting is made for each of the quadtree-split partitions. In the example of FIG. 12, partition 1204 is not further split. Partitions 1202 and 1208 each adopt another quadtree split. For partition 1202, the second level quadtree-split top-left, top-right, bottom-left, and bottom-right partitions adopts third level splitting of quadtree, 1104 of FIG. 11, non-splitting, and 1108 of FIG. 11, respective. Partition 1208 adopts another quadtree split, and the second level quadtree-split top-left, top-right, bottom-left, and bottom-right partitions adopts third level splitting of 1106 of FIG. 11, non-splitting, non-splitting, and 1104 of FIG. 11, respectively. Two of the subpartitions of the third-level top-left partition of 1208 are further split according to 1104 and 1108. Partition 1206 adopts a second level split pattern following 1102 of FIG. 11 into two partitions which are further split in a third-level according to 1108 and 1102 of the FIG. 11. A fourth level splitting is further applied to one of them according to 1104 of FIG. 11.
