INTRA-MACROBLOCK DC AND AC COEFFICIENT PREDICTION FOR INTERLACED DIGITAL VIDEO

摘要

DC and AC DCT transform coefficients of an INTRA coded block (310) are differentially encoded by selecting predictor DC and AC coefficients from a left-hand neighboring block (320) and a top neighboring block (340). Each block (310, 320, 340) is coded according to a frame mode, a reordered field mode, and a non-reordered field mode. The AC predictor block is selected according to the respective coding modes of the blocks, and the block in which a DC predictor resides. The top block (340) is selected as an AC predictor when the top block (340) and current block (310) are both reordered field mode, or both frame mode and/or non-reordered field mode, and the DC predictor resides in the top block. Zeroed AC spatial transform coefficients are used in place of the AC spatial transform coefficients from the selected block when the selected block is not INTRA coded, or does not reside in the same Video Object Plane (VOP) as the current block. DC coefficients may be non-linearly quantized.