Look-up-table based DCT domain inverse motion compensation
DCT-based digital video coding standards such as MPEG and H.26x have been widely adopted for multimedia applications. Thus video processing in the DCT domain usually proves to be more efficient than in the spatial domain. To directly convert an inter-coded frame into an intra-coded frame in the DCT domain, the problem of DCT domain inverse motion compensation was studied by Chang and Messerschmitt(1995). Since the data is organized block by block in the DCT domain, the DCT domain inverse motion compensation is computationally intensive. In this paper, a look-up-table (LUT) based method for DCT domain inverse motion compensation is proposed by modeling the statistical distribution of the DCT coefficients in typical images and video sequences. Compared to the method of Chang et al., the LUT based method can save more than 50% of the computing time based on experimental results. The memory requirement of the LUT is about 800 KB which is reasonable. Moreover, the LUT can be shared by multiple DCT domain video processing applications running on the same computer.