Control-Point Representation and Differential Coding Affine-Motion Compensation

• Published in: IEEE transactions on circuits and systems for video technology Vol. 23; no. 10; pp. 1651 - 1660
• Main Authors: Han Huang, Woods, John W., Yao Zhao, Huihui Bai
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.10.2013; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Adaptation models; Affine-motion model; Applied sciences; Bit rate; Circuit properties; Coders; Coding; Compressing; Detection, estimation, filtering, equalization, prediction; Electric, optical and optoelectronic circuits; Electronic circuits; Electronics; Encoders; Encoding; Exact sciences and technology; high-efficiency video coding (HEVC); Image processing; Information, signal and communications theory; Mathematical analysis; Mathematical models; motion estimation; motion-compensated prediction (MCP); Optimization; Predictive models; Rate-distortion; Representations; Signal and communications theory; Signal convertors; Signal processing; Signal, noise; Systems, networks and services of telecommunications; Telecommunications; Telecommunications and information theory; Transmission and modulation (techniques and equipments); Vectors; Video coding; Video coding; Performance evaluation; Moving target; Deformation; Motion estimation; Image processing; Coding circuit; Spatial correlation; Rate distortion theory; high-efficiency video coding (HEVC); Adaptive method; Optimization; Video signal processing; motion-compensated prediction (MCP); Affine-motion model; Signal processing; Random access; Zoom; Motion compensation; Delay time; High bit rate; Motion control; Control point; High rate transmission
• ISSN: 1051-8215; 1558-2205
• DOI: 10.1109/TCSVT.2013.2254977

The affine-motion model is able to capture rotation, zooming, and the deformation of moving objects, thereby providing a better motion-compensated prediction. However, it is not widely used due to difficulty in both estimation and efficient coding of its motion parameters. To alleviate this problem, a new control-point representation that favors differential coding is proposed for efficient compression of affine parameters. By exploiting the spatial correlation between adjacent coding blocks, motion vectors at control points can be predicted and thus efficiently coded, leading to overall improved performance. To evaluate the proposed method, four new affine prediction modes are designed and embedded into the high-efficiency video coding test model HM1.0. The encoder adaptively chooses whether to use the new affine mode in an operational rate-distortion optimization. Bitrate savings up to 33.82% in low-delay and 23.90% in random-access test conditions are obtained for low-complexity encoder settings. For high-efficiency settings, bitrate savings up to 14.26% and 4.89% for these two modes are observed.