2-D DCT/IDCT for JPEG Compression

Fast Implementation of 8X8 DCT/IDCT for JPEG Compression

to understand the Algorithm go to matlab help in page dct2 and idct2 to get the mathematical expression
for M = N = 8, we can calculate the most of hard values and save it as LUTs to speed up the execution

now compare our special 8X8 functions with the internal general functions

use this code:

A = int32(100*rand(8,8));
tic;for i = 1 : 1000 IDCT_8X8(DCT_8X8(A));end;toc;
tic;for i = 1 : 1000 idct2(dct2(A));end;toc;

i had built the general functions too, but with low speed