2

3 Be introduced in H.264 FRExt profile, but most H.264 profiles do not support it. Do not need motion estimation operation

4

5

6 Start Intra frame? Compute the cost of SKIP mode Perform ME process for 16×16, 16×8, and 8×16 Perform ME process for four 8×8 blocks. Compute the sub-MB mode (8×8, 8×4, 4×8, 4×4) Four 8×8 MB have finished encoding? Perform intra prediction. Compute the costs of I4MB and I16MB N Y N Y Select the mode that has the minimum cost among all the modes that have been checked End Time-consuming!

7 Cur_MB

8 Dominant!

9 Current frame Previous frame MB 0 MB 1 MB 3 MB 2 MB 4

10 For a MV=( mv x, mv y ), the city-block length = | mv x |+| mv y | For all sequence at QP=28 Hard to distinguish!

11

12

13 T low T high

14

15

16 Current frame Previous frame MB 0 MB 1 MB 3 MB 2 MB 4

17

18

19

20 Check all the modes in class 2 to 4

21

22 QP ↑, ΔT ↑ AVG % %

23 ↑

24

25 [9] J. Bu, S. Lou, C. Chen, and J. Zhu, “A predictive block-size mode selection for inter frame in H.264,” in IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP),May 2006, vol. 2, pp. 917–920 [10] I. Choi, J. Lee, and B. Jeon, “Fast coding mode selection with rate-distortion optimization for MPEG-4 part-10 AVC/H.264,” IEEE Transactions on Circuits and Systems for Video Technology, vol. 16, no. 12, pp. 1557–1561, Dec. 2006

26

27 “Foreman” sequence, QP=24

28