Adaptive deblocking algorithm based on image characteristics for low bit-rate video
ICIAR'07 Proceedings of the 4th international conference on Image Analysis and Recognition
PCM'12 Proceedings of the 13th Pacific-Rim conference on Advances in Multimedia Information Processing
Probabilistic motion-compensated prediction in distributed video coding
Multimedia Tools and Applications
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We present an estimation-theoretic analysis of motion compensation that, when used with fields of block-based motion vectors, leads to the development of overlapped block algorithms with improved compensation accuracy. Overlapped block motion compensation (OBMC) is formulated as a probabilistic linear estimator of pixel intensities given the limited block motion information available to the decoder. Although overlapped techniques have been observed to reduce blocking artifacts in video coding, this analysis establishes for the first time how (and why) OBMC can offer substantial reductions in prediction error as well, even with no change in the encoder's search and no extra side information. Performance can be further enhanced with the use of state variable conditioning in the compensation process. We describe the design of optimized windows for OBMC. We also demonstrate how, with additional encoder complexity, a motion estimation algorithm optimized for OBMC offers further significant gains in compensation accuracy. Overall mean-square prediction improvements in the range of 16 to 40% (0.8 to 2.2 dB) are demonstrated