A data converting apparatus includes a segmenting unit for setting a predetermined access unit, as an access unit to be processed, out of input data containing at least one access unit containing a plurality of data components per pixel, and for segmenting the access unit to be processed into at least one block; an analyzing unit for generating a basis for converting an expression format of each of the plurality of data components by respectively setting, as at least one analysis block, at least one segmented block and for performing a main component analysis on the plurality of data components; and a converting unit for converting the expression format of each of the plurality of data components per pixel forming the block to be processed.