An Efficient Four-Parameter Affine Motion Model for Video Coding

In this paper, we study a simplified affine motion model-based coding framework to overcome the limitation of a translational motion model and maintain low-computational complexity. The proposed framework mainly has three key contributions. First, we propose to reduce the number of affine motion parameters from 6 to 4. The proposed four-parameter affine motion model can not only handle most of the complex motions in natural videos, but also save the bits for two parameters. Second, to efficiently encode the affine motion parameters, we propose two motion prediction modes, i.e., an advanced affine motion vector prediction scheme combined with a gradient-based fast affine motion estimation algorithm and an affine model merge scheme, where the latter attempts to reuse the affine motion parameters (instead of the motion vectors) of neighboring blocks. Third, we propose two fast affine motion compensation algorithms. One is the one-step sub-pixel interpolation that reduces the computations of each interpolation. The other is the interpolation-precision-based adaptive block size motion compensation that performs motion compensation at the block level rather than the pixel level to reduce the number of interpolation. Our proposed techniques have been implemented based on the state-of-the-art high-efficiency video coding standard, and the experimental results show that the proposed techniques altogether achieve, on average, 11.1% and 19.3% bits saving for random access and low-delay configurations, respectively, on typical video sequences that have rich rotation or zooming motions. Meanwhile, the computational complexity increases of both the encoder and the decoder are within an acceptable range.

[1]  G. Bjontegaard,et al.  Calculation of Average PSNR Differences between RD-curves , 2001 .

[2]  Jong-Hyeok Lee,et al.  Zoom Motion Estimation Using Block-Based Fast Local Area Scaling , 2012, IEEE Transactions on Circuits and Systems for Video Technology.

[3]  Ju Liu,et al.  Affine Model Based Motion Compensation Prediction for Zoom , 2012, IEEE Transactions on Multimedia.

[4]  Ajay Luthra,et al.  Overview of the H.264/AVC video coding standard , 2003, SPIE Optics + Photonics.

[5]  Matthias Narroschke,et al.  Extending HEVC by an affine motion model , 2013, 2013 Picture Coding Symposium (PCS).

[6]  Cordula Heithausen,et al.  Motion compensation with higher order motion models for HEVC , 2015, 2015 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP).

[7]  Jeong-Hoon Park,et al.  Block Partitioning Structure in the HEVC Standard , 2012, IEEE Transactions on Circuits and Systems for Video Technology.

[8]  Yao Zhao,et al.  Affine SKIP and DIRECT modes for efficient video coding , 2012, 2012 Visual Communications and Image Processing.

[9]  A. Navarro,et al.  Improvements to TZ search motion estimation algorithm for multiview video coding , 2012, 2012 19th International Conference on Systems, Signals and Image Processing (IWSSIP).

[10]  F. Bossen,et al.  Common test conditions and software reference configurations , 2010 .

[11]  Yücel Altunbasak,et al.  Hierarchical motion estimation with content-based meshes , 2003, IEEE Trans. Circuits Syst. Video Technol..

[12]  Alexis M. Tourapis,et al.  Enhanced predictive zonal search for single and multiple frame motion estimation , 2002, IS&T/SPIE Electronic Imaging.

[13]  A. Murat Tekalp,et al.  Tracking Motion and Intensity Variations Using Hierarchical 2-D Mesh Modeling for Synthetic Object Transfiguration , 1996, CVGIP Graph. Model. Image Process..

[14]  Jerry Avorn Technology , 1929, Nature.

[15]  Mohammad Ghanbari,et al.  General approach to block-matching motion estimation , 1993 .

[16]  Chung-Lin Huang,et al.  A new motion compensation method for image sequence coding using hierarchical grid interpolation , 1994, IEEE Trans. Circuits Syst. Video Technol..

[17]  Hiroshi Harashima,et al.  Motion compensation based on spatial transformations , 1994, IEEE Trans. Circuits Syst. Video Technol..

[18]  Lai-Man Po,et al.  Subsampled Block-Matching for Zoom Motion Compensated Prediction , 2010, IEEE Transactions on Circuits and Systems for Video Technology.

[19]  Aggelos K. Katsaggelos,et al.  Multiple global affine motion model for H.264 video coding with low bit rate , 2005, IS&T/SPIE Electronic Imaging.

[20]  Zhiping Lin,et al.  An efficient coding scheme based on image alignment for H.264/AVC , 2009, 2009 IEEE International Symposium on Circuits and Systems.

[21]  Wen Gao,et al.  A comparison of fractional-pel interpolation filters in HEVC and H.264/AVC , 2012, 2012 Visual Communications and Image Processing.

[22]  Kai-Kuang Ma,et al.  A new diamond search algorithm for fast block-matching motion estimation , 2000, IEEE Trans. Image Process..

[23]  Wan-Chi Siu,et al.  Local affine motion prediction for H.264 without extra overhead , 2010, Proceedings of 2010 IEEE International Symposium on Circuits and Systems.

[24]  Bin Li,et al.  Parsing robustness in High Efficiency Video Coding - analysis and improvement , 2011, 2011 Visual Communications and Image Processing (VCIP).

[25]  Fan Liang,et al.  Affine SKIP and MERGE modes for video coding , 2015, 2015 IEEE 17th International Workshop on Multimedia Signal Processing (MMSP).

[26]  Ajay Luthra,et al.  Overview of the H.264/AVC video coding standard , 2003, IEEE Trans. Circuits Syst. Video Technol..

[27]  Lap-Pui Chau,et al.  Hexagon-based search pattern for fast block motion estimation , 2002, IEEE Trans. Circuits Syst. Video Technol..

[28]  Detlev Marpe,et al.  Block Merging for Quadtree-Based Partitioning in HEVC , 2012, IEEE Transactions on Circuits and Systems for Video Technology.

[29]  Yao Zhao,et al.  Control-Point Representation and Differential Coding Affine-Motion Compensation , 2013, IEEE Transactions on Circuits and Systems for Video Technology.

[30]  Houqiang Li,et al.  An affine motion compensation framework for high efficiency video coding , 2015, 2015 IEEE International Symposium on Circuits and Systems (ISCAS).

[31]  Zhaoyang Lu,et al.  Model Based Motion Vector Predictor for Zoom Motion , 2010, IEEE Signal Processing Letters.

[32]  Gary J. Sullivan,et al.  Overview of the High Efficiency Video Coding (HEVC) Standard , 2012, IEEE Transactions on Circuits and Systems for Video Technology.

[33]  Shahram Shirani,et al.  Affine Motion Prediction Based on Translational Motion Vectors , 2007, IEEE Transactions on Circuits and Systems for Video Technology.