A Novel Search Algorithm for Variable Block Size Motion Estimation of H.264/avc

Variable block size ME (VBSME) is adopted in H.264, to achieve significant video quality and coding efficiency. However, the VBSME requires much higher computational complexity than the fixed block size ME (FBSME). In H.264, tree-structured block sizes are employed (Ahmadi et al 2008). Each 16x16 macro block (MB) can be coded in 16 x 16, 16 x 8, 8 x 16, or 8 x 8 block modes. If 8 x 8 modes are chosen, each 8 x 8 block can be further divided into 8 x 8, 8 x 4, 4 x 8, and 4 x 4 sub-blocks. Totally, there are seven blocks modes and forty-one sub-blocks, as depicted in Figure 5.1.