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 16x16 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 x 16 block mode. The proposed algorithm shows the average speed-up factors of 41.9 similar to 58.57% for IBBPBB sequences with a negligible bit increment and a minimal loss of image quality.