A method of utilizing an 8-bit primary transform core matrix to decode compressed video or image data or encode uncompressed video or image data. The method may include determining whether to use a first transform core matrix that is of a first size type or a second transform core matrix that is of a second size type that is smaller than the first size type. When a result of the determination is to use the first transform core matrix, encoding or decoding the target file using the 8-bit primary transform core matrix that has the size that is 64-point or larger. If not, the method may include extracting the second transform core matrix of the second size type from the first transform matrix and encoding or decoding the target file using the extracted second transform core matrix.