Patent ID: 6826231
Filing Date: 2004-11-30
Classification: H04N

Abstract:
A motion vector conversion method for an image information conversion method wherein a bit stream representative of interlaced scanned image compression information of MPEG2 is inputted and a bit stream representative of progressively scanned image compression information of MPEG4 is outputted, comprising the steps of:successively accepting 16Ã—16 motion vectors of MPEG2 of the inputted bit stream representative of image compression information of MPEG2; and successively producing 8Ã—8 motion vectors of MPEG4 and 16Ã—16 motion vectors of MPEG4 based on the 16Ã—16 motion vectors of MPEG2 such that every other one of P frames of the bit stream of MPEG2 is dropped to produce a bit stream of MPEG4 of a reduced frame rate and a low bit rate; the successively producing step serving also as a motion vector modification step and including a step of storing information of each of macro blocks and between blocks in the inputted bit stream representative of image compression information of MPEG2 in advance, a step of duplicating motion vectors of a P frame immediately preceding reach P frame to be dropped based on the stored information and a step of extending the duplicated motion vectors to twice in the temporal direction to produce motion vectors of MPEG4 converted from an intraframe of MPEG2.