Signiicance{linked Connected Component Analysis for Very Low Bit Rate Wavelet Video Coding

In recent years, a tremendous success in wavelet image coding has been achieved. It is mainly attributed to innovative strategies for data organization and representation of wavelet-transformed images. However, there have been only a few successful attempts in wavelet video coding. The most successful one is perhaps Sarnoo Corporation's zerotree entropy (ZTE) video coder. In the paper, a novel hybrid wavelet video coding algorithm termed video signiicance-linked connected component analysis (VSLCCA) is developed for very low bit rate applications. It has also been empirically evidenced that wavelet transform combined with those innovative data organization and representation strategies can be an invaluable asset in very low bit rate video coding as long as motion-compensated error frames are ensured to be blocking-eeect-free or coherent. In the proposed VSLCCA codec, rst, ne-tuned motion estimation based on H.263 Recommendation is developed to reduce temporal redundancy and exhaustive overlapped block motion compensation is utilized to ensure the coherency in motion-compensated error frames, second, wavelet transform is applied to each coherent motion-compensated error frame to attain global energy compaction, third, signiicant elds of wavelet-transformed error frame are organized and represented as signiicance-linked connected components so that both the within-subband clustering and cross-scale dependency are exploited, nally, the horizontal and vertical components of motion vectors are encoded separately using adaptive arithmetic coding while signiicant wavelet coee-cients are encoded in bit-plane order by using high order Markov source modeling and adaptive arithmetic coding. Experimental results on eight standard MPEG-4 test sequences show that for intraframe coding, on average the proposed codec exceeds H.263 and ZTE in PSNR by as much as 2.07 dB and 1.38 dB at 28 kbits, respectively. For entire sequence coding, VSLCCA is superior to H.263 and ZTE by 0.35 dB and 0.71 dB on average, respectively.