Outline  Introduction  Observations and analysis  Proposed algorithm  Experimental results 2

Introduction (1/2)Introduction (1/2)  Coding structure proposed by HHI: 3 View-0 View-1 Time = t Time = t-1 disparity estimation motion estimation

Introduction (2/2) Global Disparity Vector (GDV) 4 View Time GDV ahead GDV behind GDV cur …… Non-anchor frameAnchor frame Ref. view (view 0)

Observations (1/2)Observations (1/2)  T: Temporal prediction  Static BG, homogeneous region  Small block size mode for complex motion  V: View prediction  Complex motion 5

Observations (2/2)Observations (2/2)  Block size distribution:  Only the MBs in the region with complex motion need DE and small mode size ME. 6

Goal  Try to decide in advance:  the optimal prediction direction (ME/DE) for MBs  the prediction size is 16×16 or not 7

Motion homogeneity determined (1/4)  A uniform motion vector field at 4×4 block level is generated.  MB m,n : a MB located at the m th row, n th column.  : the MVs of its convered 4 × 4 blocks. 8

Motion homogeneity determined (2/4)  Neighbor MBs used in calculating the motion homogeneity: 9 Current MB

Motion homogeneity determined (3/4)  The motion homogeneities of MB m,n in horizontal and vertical directions are defined as:  The motion homogeneities of MB m,n is defined as: 10

Motion homogeneity determined (4/4)  If MD(m,n) < T then the MB is considered with homogeneous motion. Otherwise, the MB is considered with complex motion.  The threshold T is fixed for each QP level and different sequences, which is set to

Selective disparity estimationSelective disparity estimation  MB with homogeneous motion is likely to choose temporal prediction.  If a MB satisfies the criterion of spatially homogenous motion, inter-view prediction can be skipped. 12

Selective variable size motion estimation  When a MB is with homogeneous motion, the best mode size of the MB has a very large probability to be 16×16. 13

Proposed fast DE/ME algorithmProposed fast DE/ME algorithm 1)Derive MV from left, above, left-above MB, and the corresponding MB in the previously coded view. 2)Compute the motion homogeneity for current MB. 3)If a MB is a homogeneous motion, perform 16x16 ME, and go to step 6, otherwise, go to step 4. 4)Perform variable size DE and ME. 5)Perform intra 4x4 prediction. 6)Perform intra 16x16 prediction. 7)Determine the best prediction direction and prediction mode. Go to step 1 and proceed with next MB. 14

Experimental results (1/4) Experimental environment  JMVM 6.0  Test sequences (total of 9):  Downflamence2, Flamencol, Golf1, Golf2, Race1, Exit, Ballroom, Jungle, Uli  Full temporal prediction modes and inter-view prediction (FMD)  3 views are coded  QP: 20, 24, 28, 32  CABAC, loop filter are enabled 15

Experimental results (2/4)Experimental results (2/4)  Comparison between the proposed method and FMD in JMVM: 16

Experimental results (3/4)Experimental results (3/4) 17

Experimental results (4/4)Experimental results (4/4)  Compares with other method [11] : 18 [11] X. Li, D. Zhao, X. Ji, Q. Wang, and W. Gao, “A fast inter frame prediction algorithm for multi-view video coding,” in ICIP, 2007.

Outline  Goal  Proposed algorithm  Experimental results 20

Goal  Using both MB-based region segmentation information and global disparity vector (GDV) among view to reduce encoding time.  Fast mode decision using GDV. 21

Region partition (1/2)Region partition (1/2)  The proposed segmentation of the background and objects block modes for fast mode decision in inter-view prediction:  An MB is decided as background block mode if a derive motion vector is smaller than ¼ in integer pixel unit in case of Direct mode, Inter 16x16, P_SKIP or B_SKIP mode. 22

Region partition (2/2)Region partition (2/2)  Black block : object region  White block : background region 23

Fast mode decision for inter-view prediction  Regions of the vies using inter-view prediction are estimated using MB-based GDV and region segmentation map of reference view. 24 Region segmentation information of base-view Region segmentation information of non-base view using GDV and (a)

Flow chartFlow chart 25

Experimental resultsExperimental results 26