cpp.rar_DCT变换_dct_dct cpp

#include "stdio.h" #include "fstream.h" /********************************************************************** * * Name: IDCT * Description: perform idct function * * Input: block number * * Returns: none * Side effects: * * Date: 2005.11.08 * ***********************************************************************/ void main() { const short c1 = 0x0B19, c2 = 0x0A74, c3 = 0x0968; const short c5 = 0x0649, c6 = 0x0454, c7 = 0x0235; const int c4_shift = 11; const int round1 = 256, round2 = 32768; const int trunc1 = 9, trunc2 = 16; int io_ptr[64]={72,23,88,83,90,1,42,130, 83,99,34,21,65,23,33,9, 71,43,90,223,51,83,99,1, 88,109,190,66,93,43,78,11, 90,123,20,83,90,12,1,2, 99,32,43,84,83,26,222,245, 1,79,255,93,12,53,66,87, 90,80,31,83,12,34,92,100}; int i,j, count=0;; short X0, X1, X2, X3, X4, X5, X6, X7; /* Freq domain terms */ int P0, P1, p0, p1, r0, r1; /* Even-half temp */ int g0, g1, h1, h0; /* Even-half result */ int g2, g3, h3, h2; /* Odd-half result */ int x0, x1, x2, x3, x4, x5, x6, x7; /* Resulting samples */ int x0t,x1t,x2t,x3t,x4t,x5t,x6t,x7t; /* Truncated result */ int x0s,x1s,x2s,x3s,x4s,x5s,x6s,x7s; /* Saturated result */ /* ---------------------------------------------------------- */ /* Avoid running the code if we don't have any IDCTs to do. */ /* ---------------------------------------------------------- */ /* ---------------------------------------------------------- */ /* Set up pointers. */ /* ---------------------------------------------------------- */ /*io_ptr = data[block_no][0]+64-8; */ i=0; for (j = 0; j < 8; j++) { /* ---------------------------------------------------- */ /* Load the freq-domain coefficients. */ /* ---------------------------------------------------- */ X0 = io_ptr[i]; X1 = io_ptr[1+i]; X2 = io_ptr[2+i]; X3 = io_ptr[3+i]; X4 = io_ptr[4+i]; X5 = io_ptr[5+i]; X6 = io_ptr[6+i]; X7 = io_ptr[7+i]; /* ---------------------------------------------------- */ /* Even part of decomp. Add rounding to DC term. */ /* ---------------------------------------------------- */ P0 = (((int)X0) << c4_shift) + round1; P1 = (((int)X4) << c4_shift); p0 = P0 + P1; p1 = P0 - P1; r1 = X2*c6 - X6*c2; r0 = X2*c2 + X6*c6; g0 = p0 + r0; g1 = p1 + r1; h1 = p1 - r1; h0 = p0 - r0; /* ---------------------------------------------------- */ /* Odd part of decomp. */ /* ---------------------------------------------------- */ g2 = (X1*c7 - X3*c5) + (X5*c3 - X7*c1); g3 = (X1*c5 - X3*c1) + (X5*c7 + X7*c3); h3 = (X1*c3 - X3*c7) - (X5*c1 + X7*c5); h2 = (X1*c1 + X3*c3) + (X5*c5 + X7*c7); /* ---------------------------------------------------- */ /* Final butterfly. */ /* ---------------------------------------------------- */ x0 = g0 + h2; x1 = g1 + h3; x2 = h1 + g3; x3 = h0 + g2; x4 = h0 - g2; x5 = h1 - g3; x6 = g1 - h3; x7 = g0 - h2; /* ---------------------------------------------------- */ /* Truncate to fit back into 16 bits. */ /* ---------------------------------------------------- */ x0t = x0 >> trunc1; x1t = x1 >> trunc1; x2t = x2 >> trunc1; x3t = x3 >> trunc1; x4t = x4 >> trunc1; x5t = x5 >> trunc1; x6t = x6 >> trunc1; x7t = x7 >> trunc1; /* ---------------------------------------------------- */ /* Store the results transposed. */ /* ---------------------------------------------------- */ io_ptr[i] = x0t; io_ptr[1+i] =