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Motion Predictors and Motion Predictors and Motion Estimation in H.264Motion Estimation in H.264
K. C. YangK. C. Yang
OutlineOutline
Variable Size Block Matching in H.264Variable Size Block Matching in H.264 Concept of Variable Block SizesConcept of Variable Block Sizes Motion Vector Predictors in H.264Motion Vector Predictors in H.264
Fast Integer Motion Estimation for H.264 Fast Integer Motion Estimation for H.264 Video Coding StandardVideo Coding Standard
An Unsymmetrical-Cross Multi-Resolution An Unsymmetrical-Cross Multi-Resolution Motion Search Algorithm for MPEG4-Motion Search Algorithm for MPEG4-AVC/H.264 CodingAVC/H.264 Coding
Block Type DecisionBlock Type Decision
Minimize the cost functionMinimize the cost function
mm : Motion vector : Motion vector pp : Predicted motion vector : Predicted motion vector MOTIONMOTION : Largrange multiplier : Largrange multiplier cc : current frame : current frame rr : reference frame : reference frame
( , ) ( , ( )) ( )MOTION MOTIONJ m SAD c r m R m p
Predicted MV
Real MV
cr
MV predictorsMV predictors
UP UR
LF
UP UR
LF
UP UR
LF
pMV = median (MVpMV = median (MVUPUP, MP, MPURUR, MV, MVLFLF ) )
pMVpMVUPUP = MV = MVUPUP, pMV, pMVDOWNDOWN = MV = MVLFLF
pMVpMVLEFTLEFT = MV = MVLFLF, pMV, pMVRIGHTRIGHT = MV = MVURUR
MV predictorsMV predictors
pMVpMVaa = median (MV = median (MVUPUP, MP, MPURUR, MV, MVLFLF ) )
pMVpMVbb = median (MV = median (MVUPUP, MP, MPURUR, MV, MVaa ) )
pMVpMVcc = median (MV = median (MVaa, MP, MPbb, MV, MVLFLF ) )
pMVpMVdd = median (MV = median (MVaa, MP, MPbb, MV, MVcc ) )
a bc d
UP UR
LF
Fast Integer Motion Fast Integer Motion Estimation for H.264 Video Estimation for H.264 Video
Coding StandardCoding StandardAndy Chang, Peter H. W. Wong, Y.M. Yeung, and OscaAndy Chang, Peter H. W. Wong, Y.M. Yeung, and Osca
r C. Aur C. Au
The Hong Kong University of Science and TechnologyThe Hong Kong University of Science and Technology
ICME 2004ICME 2004
ObservationObservation
Hit ratio Hit ratio (8 x 8 MV = 16 x 16 MV)(8 x 8 MV = 16 x 16 MV)
(MV(MV88xx – MV – MV1616xx, MV, MV88yy – MV – MV1616yy))
Integer MVInteger MV Sub-pel MVSub-pel MV
Foreman QCIFForeman QCIF 93%93% 76.6%76.6%
Stefan QCIFStefan QCIF 90%90% 82.6%82.6%
0 1
2 3
Block 0 Block 1
AlgorithmAlgorithm
8 x 8 block8 x 8 block Full searchFull search
16 x 16 block16 x 16 block MVMVaa, MV, MVbb, MV, MVcc, median(MV, median(MVUPUP, MV, MVURUR,MV,MVLFLF))
16 x 8 block16 x 8 block Up : MVUp : MVaa, MV, MVbb, MV, MVUPUP
Down : MVDown : MVcc, MV, MVdd, MV, MVLFLF
8 x 16 block8 x 16 block Left : MVLeft : MVaa, MV, MVcc, MV, MVLFLF
Right : MVRight : MVbb, MV, MVdd, MV, MVURUR
LF
UP UR
a b
c d
The ME is performed around the eight neighboring locations of the best predicted MV.
Simulation ResultsSimulation Results
On average 69.7% computation saving.On average 69.7% computation saving.
Stefan
An Unsymmetrical-Cross An Unsymmetrical-Cross Multi-Resolution Motion Multi-Resolution Motion
Search Algorithm for Search Algorithm for MPEG4-AVC/H.264 CodingMPEG4-AVC/H.264 Coding
Peng Yang, Yu-Wen He, and Shi Qiang YangPeng Yang, Yu-Wen He, and Shi Qiang Yang
Tsinghua University, ChinaTsinghua University, China
ICME 2004ICME 2004
AlgorithmAlgorithm
Predictor selectionPredictor selection
Motion estimationMotion estimation Unsymmetrical-cross searchUnsymmetrical-cross search Multi-resolution grid searchMulti-resolution grid search Extended hexagon-diamond based searchExtended hexagon-diamond based search
16 x 16 block16 x 16 block (0, 0), default predicted MV(0, 0), default predicted MV
OthersOthers (0, 0), default predicted MV, and up layer MV(0, 0), default predicted MV, and up layer MV e.g.e.g.
Use the Lagrangian cost function to find thUse the Lagrangian cost function to find the minimum.e minimum.
MV Predictors SelectionMV Predictors Selection
Multi-Resolution Grid SearchMulti-Resolution Grid SearchExtended hexagon-diamond Extended hexagon-diamond
based searchbased search
Simulation ResultsSimulation Results
Compare with the Fast Full Search in JM6.1Compare with the Fast Full Search in JM6.1
time saving