1. A method for performing an inverse discrete cosine transform (IDCT) upon a matrix of DCT coefficients associated with a video image in a video system comprising: multiplying said matrix of DCT coefficients by a symmetric pre-scale factor array to produce a pre-scaled array; performing an intermediary calculation column-wise upon said pre-scaled array to obtain an intermediary array; and performing a final calculation row-wise upon said intermediary array; wherein said symmetric pre-scale factor array is an array expressible by the product M.times.U.times.M, where U is a matrix of coefficients each being equal to 1 and M is an array wherein a set of pre-scale constants are expressed along its diagonal and wherein all other coefficients are 0; and creating a video bitstream representative of said video image using results from said final calculation.