Fast block mode decision scheme for B-picture coding in H.264/AVC

The recent H.264/AVC video coding standard provides a higher coding efficiency than previous standards. H.264/AVC achieves a bit rate saving of more than 50 % with many new technologies, but it is computationally complex. Most of fast mode decision algorithms have focused on Baseline profile of H.264/AVC which does not consider B-picture coding. In this paper, a fast block mode decision scheme for B-pictures in High profile and Main profile is proposed to reduce the computational complexity for H.264/AVC. To reduce the block mode decision complexity in B-pictures of High profile, we use the SAD value after 16×16 block motion estimation. This SAD value is used for the classification feature to divide all block modes into some proper candidate search block modes. A differential mode allocation method is also used for the list (list 0, list 1) of B-slices based on the SAD value of the 16 × 16 block mode. The proposed algorithm shows the average speed-up factors of 41.9 ~ 58.57% for IBBPBB sequences with a negligible bit increment and a minimal loss of image quality.