Y. Morvan, D. Farin, and P.H.N. de With (The Netherlands)
MPEG-4 video coding, shape-adaptive transforms, Match ing Pursuit.
The key aspect of Matching Pursuit is that the video sig nal can be represented with less coefficients than with an orthogonal transform, due to the over-complete set of ba sis functions. This paper describes how Matching Pur suit can be employed in an MPEG-4 video encoder as a replacement for the Discrete Cosine Transform (DCT) at boundary-blocks to improve coding efficiency, while re taining backward compatibility. We show why a direct in tegration of Matching Pursuit can lead to bad coding per formance resulting from unfavorable coefficient statistics. Instead, the Matching Pursuit algorithm is modified to in crease the compression efficiency with a newly developed dictionary pruning scheme. Experimental results show that it can improve the obtained PSNR by up to 1 dB at object boundaries when compared to the basic Matching Pursuit.
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