METHOD AND APPARATUS FOR INVERSE QUANTIZATION OF MPEG-4 VIDEO

摘要

Inverse quantization (36, 44, 60) of a two-dimensional array of video coefficients QF[v][u] is provided. A first weighting matrix W[0][v][u]=2*W[0][v][u] for intra-coded macroblocks and a second weighting matrix W[1][v][u]=2*W[1][v][u] for non-intra-coded macroblocks are pre-computed and stored (88). A quantization difference (quanti+1) to be used in selecting a weight factor is computed (70) based on a current macroblock quantization level. The weight factor is output from one of the weighting matrices in response to the quantization difference and a macroblock type identifier (66) (i.e., intra-coded or non-intra-coded). Subsequent weights Wi+1[w][v][u] are then computed (86) from a current weight Wi[w][v][u] and the weight factor. The array of coefficients QF[v][u] is multiplied (92) by the weights Wi+1[w][v][u] to reconstruct unquantized coefficients.