Performing optimal bit-allocation with 3-D wavelet coding methods is difficult because energy is not conserved after applying the motion-compensated temporal filtering (MCTF) process and the spatial wavelet transform. The problem cannot be solved by extending the 2-D wavelet coefficients weighting method directly and then applying the result to 3-D wavelet coefficients, since this approach does not consider the complicated pixel connectivity that results from the lifting-based MCTF process. In this paper, we propose a novel weighting method, which takes account of the pixel connectivity, to solve the problem and derive the effect of the quantization error of a subband on the reconstruction error of a group of pictures. We employ the proposed method on a 2-D + t structure with different temporal filters, namely the 5-3 filter and the 9-7 filter. Experiments on various coding parameters and sequences show that the proposed approach improves the bit-allocation performance over that obtained by using the weightings derived without considering the pixel connectivity in the MCTF process.

In this paper, we propose a novel way to derive the weighting for subbands that conserves energy. Once the weight of each subband has been calculated by motion-compensation temporal filtering, the effect of the quantization error of a subband on the reconstruction error of a group of pictures can be determined. Then, we weigh each subband and use the weighted coefficients to derive the optimal bit-allocation solution for 3-D wavelet coding methods. We apply the proposed method to bit-allocation on a 2D+t structure with a 5-3 temporal wavelet filter, and show that it achieves a 0.5–1.5 dB peak-signal-to-noise improvement over using the weighting of subbands on various coding parameters and sequences.

We compare, both objectively and subjectively, the performance of various advanced motion compensation methods, including overlapped block motion compensation (OBMC) and control grid interpolation (CGI), in a 3-D wavelet-based coding system. The motion vectors of the methods are obtained by using a sequence of 1-D dynamic programming algorithms that minimizes the cost function. Our experiment results indicate that an OBMC sequence usually has a higher peak signal-to-noise ratio (PSNR) than other methods, while a CGI sequence usually contains the fewest blocking artifacts. We provide a simple framework that combines the OBMC and CGI sequences. The proposed hybrid method removes more than 50% of the blocking artifacts of an OBMC sequence, while simultaneously maintaining a high PSNR performance.

This paper describes a new 3-D framework for the construction of a hybrid motion compensation model to reduce blocking artifacts in a highly scalable video coding system. Previous works have focused primarily on using control grid interpolation (CGI) or over-lapped block motion compensation (OBMC) to reduce blocking artifacts. However, both methods generate distinct side effects, such as PSNR degradation or poor de-blocking results, during the de-blocking process. The main objective of our proposed model is to achieve better visual quality and maintain satisfactory coding efficiency simultaneously by integrating the advantages of CGI and OBMC. The introduction of the dual mode selection between CGI and OBMC provides a more flexible mechanism to adjust our objective function and thereby achieves higher objective and subjective coding gains. Experimental results show that our proposed model achieves improved coding efficiency in terms of both PSNR and visual quality.