Fast Mode Decision for H.264/AVC Based on Macroblock Motion Activity. Huanqiang Zeng Canhui Cai , IEEE senior member Kai- Kuang Ma, IEEE senior member CSVT April,2009. Outline. Introduction Overview of H.264/AVC’s mode decision Fast mode decision methods
CanhuiCai, IEEE senior member
Kai-Kuang Ma, IEEE senior member
Do not need motion estimation operation
Be introduced in H.264 FRExt profile, but most H.264 profiles do not support it.
Four 8×8 MB have finished encoding?
Compute the cost of
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)
Perform intra prediction.
Compute the costs of I4MB and I16MB
Select the mode that has the minimum cost among all the modes that have been checked
Small block size → region containing fast moving objects
Hard to distinguish!
For all sequence at QP=28
For a MV=(mvx,mvy),
the city-block length = |mvx|+|mvy|
Check all the modes in class 2 to 4
 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
 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
“Foreman” sequence, QP=24