“…As we know, in the 1-D hierarchical coding structure, the depth first coding order can lead to the least reference buffer size [14]. For example, The encoding order of a typical 1-D hierarchical coding structure with GOP size 16 is 0, 16,8,4,2,1,3,6,5,7,12,10,9,11,14,13,15. And the optimal size of the reference buffer is 5.…”