jrevdct.c

linux下将各类格式图片转换工具

		    tmp11 = tmp12 = -tmp10;
		}
	    }
	} else {
	    if (d2) {
		if (d0) {
		    /* d0 != 0, d2 != 0, d4 == 0, d6 == 0 */
		    tmp2 = MULTIPLY(d2, FIX_0_541196100);
		    tmp3 = MULTIPLY(d2, FIX_1_306562965);

		    tmp0 = d0 << CONST_BITS;

		    tmp10 = tmp0 + tmp3;
		    tmp13 = tmp0 - tmp3;
		    tmp11 = tmp0 + tmp2;
		    tmp12 = tmp0 - tmp2;
		} else {
		    /* d0 == 0, d2 != 0, d4 == 0, d6 == 0 */
		    tmp2 = MULTIPLY(d2, FIX_0_541196100);
		    tmp3 = MULTIPLY(d2, FIX_1_306562965);

		    tmp10 = tmp3;
		    tmp13 = -tmp3;
		    tmp11 = tmp2;
		    tmp12 = -tmp2;
		}
	    } else {
		if (d0) {
		    /* d0 != 0, d2 == 0, d4 == 0, d6 == 0 */
		    tmp10 = tmp13 = tmp11 = tmp12 = d0 << CONST_BITS;
		} else {
		    /* d0 == 0, d2 == 0, d4 == 0, d6 == 0 */
		    tmp10 = tmp13 = tmp11 = tmp12 = 0;
		}
	    }
	}
    }

    /* Odd part per figure 8; the matrix is unitary and hence its
     * transpose is its inverse.  i0..i3 are y7,y5,y3,y1 respectively.
     */
    if (d7) {
	if (d5) {
	    if (d3) {
		if (d1) {
		    /* d1 != 0, d3 != 0, d5 != 0, d7 != 0 */
		    z1 = d7 + d1;
		    z2 = d5 + d3;
		    z3 = d7 + d3;
		    z4 = d5 + d1;
		    z5 = MULTIPLY(z3 + z4, FIX_1_175875602);
		    
		    tmp0 = MULTIPLY(d7, FIX_0_298631336); 
		    tmp1 = MULTIPLY(d5, FIX_2_053119869);
		    tmp2 = MULTIPLY(d3, FIX_3_072711026);
		    tmp3 = MULTIPLY(d1, FIX_1_501321110);
		    z1 = MULTIPLY(-z1, FIX_0_899976223);
		    z2 = MULTIPLY(-z2, FIX_2_562915447);
		    z3 = MULTIPLY(-z3, FIX_1_961570560);
		    z4 = MULTIPLY(-z4, FIX_0_390180644);
		    
		    z3 += z5;
		    z4 += z5;
		    
		    tmp0 += z1 + z3;
		    tmp1 += z2 + z4;
		    tmp2 += z2 + z3;
		    tmp3 += z1 + z4;
		} else {
		    /* d1 == 0, d3 != 0, d5 != 0, d7 != 0 */
		    z1 = d7;
		    z2 = d5 + d3;
		    z3 = d7 + d3;
		    z5 = MULTIPLY(z3 + d5, FIX_1_175875602);
		    
		    tmp0 = MULTIPLY(d7, FIX_0_298631336); 
		    tmp1 = MULTIPLY(d5, FIX_2_053119869);
		    tmp2 = MULTIPLY(d3, FIX_3_072711026);
		    z1 = MULTIPLY(-d7, FIX_0_899976223);
		    z2 = MULTIPLY(-z2, FIX_2_562915447);
		    z3 = MULTIPLY(-z3, FIX_1_961570560);
		    z4 = MULTIPLY(-d5, FIX_0_390180644);
		    
		    z3 += z5;
		    z4 += z5;
		    
		    tmp0 += z1 + z3;
		    tmp1 += z2 + z4;
		    tmp2 += z2 + z3;
		    tmp3 = z1 + z4;
		}
	    } else {
		if (d1) {
		    /* d1 != 0, d3 == 0, d5 != 0, d7 != 0 */
		    z1 = d7 + d1;
		    z2 = d5;
		    z3 = d7;
		    z4 = d5 + d1;
		    z5 = MULTIPLY(z3 + z4, FIX_1_175875602);
		    
		    tmp0 = MULTIPLY(d7, FIX_0_298631336); 
		    tmp1 = MULTIPLY(d5, FIX_2_053119869);
		    tmp3 = MULTIPLY(d1, FIX_1_501321110);
		    z1 = MULTIPLY(-z1, FIX_0_899976223);
		    z2 = MULTIPLY(-d5, FIX_2_562915447);
		    z3 = MULTIPLY(-d7, FIX_1_961570560);
		    z4 = MULTIPLY(-z4, FIX_0_390180644);
		    
		    z3 += z5;
		    z4 += z5;
		    
		    tmp0 += z1 + z3;
		    tmp1 += z2 + z4;
		    tmp2 = z2 + z3;
		    tmp3 += z1 + z4;
		} else {
		    /* d1 == 0, d3 == 0, d5 != 0, d7 != 0 */
		    tmp0 = MULTIPLY(-d7, FIX_0_601344887); 
		    z1 = MULTIPLY(-d7, FIX_0_899976223);
		    z3 = MULTIPLY(-d7, FIX_1_961570560);
		    tmp1 = MULTIPLY(-d5, FIX_0_509795579);
		    z2 = MULTIPLY(-d5, FIX_2_562915447);
		    z4 = MULTIPLY(-d5, FIX_0_390180644);
		    z5 = MULTIPLY(d5 + d7, FIX_1_175875602);
		    
		    z3 += z5;
		    z4 += z5;
		    
		    tmp0 += z3;
		    tmp1 += z4;
		    tmp2 = z2 + z3;
		    tmp3 = z1 + z4;
		}
	    }
	} else {
	    if (d3) {
		if (d1) {
		    /* d1 != 0, d3 != 0, d5 == 0, d7 != 0 */
		    z1 = d7 + d1;
		    z3 = d7 + d3;
		    z5 = MULTIPLY(z3 + d1, FIX_1_175875602);
		    
		    tmp0 = MULTIPLY(d7, FIX_0_298631336); 
		    tmp2 = MULTIPLY(d3, FIX_3_072711026);
		    tmp3 = MULTIPLY(d1, FIX_1_501321110);
		    z1 = MULTIPLY(-z1, FIX_0_899976223);
		    z2 = MULTIPLY(-d3, FIX_2_562915447);
		    z3 = MULTIPLY(-z3, FIX_1_961570560);
		    z4 = MULTIPLY(-d1, FIX_0_390180644);
		    
		    z3 += z5;
		    z4 += z5;
		    
		    tmp0 += z1 + z3;
		    tmp1 = z2 + z4;
		    tmp2 += z2 + z3;
		    tmp3 += z1 + z4;
		} else {
		    /* d1 == 0, d3 != 0, d5 == 0, d7 != 0 */
		    z3 = d7 + d3;
		    
		    tmp0 = MULTIPLY(-d7, FIX_0_601344887); 
		    z1 = MULTIPLY(-d7, FIX_0_899976223);
		    tmp2 = MULTIPLY(d3, FIX_0_509795579);
		    z2 = MULTIPLY(-d3, FIX_2_562915447);
		    z5 = MULTIPLY(z3, FIX_1_175875602);
		    z3 = MULTIPLY(-z3, FIX_0_785694958);
		    
		    tmp0 += z3;
		    tmp1 = z2 + z5;
		    tmp2 += z3;
		    tmp3 = z1 + z5;
		}
	    } else {
		if (d1) {
		    /* d1 != 0, d3 == 0, d5 == 0, d7 != 0 */
		    z1 = d7 + d1;
		    z5 = MULTIPLY(z1, FIX_1_175875602);

		    z1 = MULTIPLY(z1, FIX_0_275899380);
		    z3 = MULTIPLY(-d7, FIX_1_961570560);
		    tmp0 = MULTIPLY(-d7, FIX_1_662939225); 
		    z4 = MULTIPLY(-d1, FIX_0_390180644);
		    tmp3 = MULTIPLY(d1, FIX_1_111140466);

		    tmp0 += z1;
		    tmp1 = z4 + z5;
		    tmp2 = z3 + z5;
		    tmp3 += z1;
		} else {
		    /* d1 == 0, d3 == 0, d5 == 0, d7 != 0 */
		    tmp0 = MULTIPLY(-d7, FIX_1_387039845);
		    tmp1 = MULTIPLY(d7, FIX_1_175875602);
		    tmp2 = MULTIPLY(-d7, FIX_0_785694958);
		    tmp3 = MULTIPLY(d7, FIX_0_275899380);
		}
	    }
	}
    } else {
	if (d5) {
	    if (d3) {
		if (d1) {
		    /* d1 != 0, d3 != 0, d5 != 0, d7 == 0 */
		    z2 = d5 + d3;
		    z4 = d5 + d1;
		    z5 = MULTIPLY(d3 + z4, FIX_1_175875602);
		    
		    tmp1 = MULTIPLY(d5, FIX_2_053119869);
		    tmp2 = MULTIPLY(d3, FIX_3_072711026);
		    tmp3 = MULTIPLY(d1, FIX_1_501321110);
		    z1 = MULTIPLY(-d1, FIX_0_899976223);
		    z2 = MULTIPLY(-z2, FIX_2_562915447);
		    z3 = MULTIPLY(-d3, FIX_1_961570560);
		    z4 = MULTIPLY(-z4, FIX_0_390180644);
		    
		    z3 += z5;
		    z4 += z5;
		    
		    tmp0 = z1 + z3;
		    tmp1 += z2 + z4;
		    tmp2 += z2 + z3;
		    tmp3 += z1 + z4;
		} else {
		    /* d1 == 0, d3 != 0, d5 != 0, d7 == 0 */
		    z2 = d5 + d3;
		    
		    z5 = MULTIPLY(z2, FIX_1_175875602);
		    tmp1 = MULTIPLY(d5, FIX_1_662939225);
		    z4 = MULTIPLY(-d5, FIX_0_390180644);
		    z2 = MULTIPLY(-z2, FIX_1_387039845);
		    tmp2 = MULTIPLY(d3, FIX_1_111140466);
		    z3 = MULTIPLY(-d3, FIX_1_961570560);
		    
		    tmp0 = z3 + z5;
		    tmp1 += z2;
		    tmp2 += z2;
		    tmp3 = z4 + z5;
		}
	    } else {
		if (d1) {
		    /* d1 != 0, d3 == 0, d5 != 0, d7 == 0 */
		    z4 = d5 + d1;
		    
		    z5 = MULTIPLY(z4, FIX_1_175875602);
		    z1 = MULTIPLY(-d1, FIX_0_899976223);
		    tmp3 = MULTIPLY(d1, FIX_0_601344887);
		    tmp1 = MULTIPLY(-d5, FIX_0_509795579);
		    z2 = MULTIPLY(-d5, FIX_2_562915447);
		    z4 = MULTIPLY(z4, FIX_0_785694958);
		    
		    tmp0 = z1 + z5;
		    tmp1 += z4;
		    tmp2 = z2 + z5;
		    tmp3 += z4;
		} else {
		    /* d1 == 0, d3 == 0, d5 != 0, d7 == 0 */
		    tmp0 = MULTIPLY(d5, FIX_1_175875602);
		    tmp1 = MULTIPLY(d5, FIX_0_275899380);
		    tmp2 = MULTIPLY(-d5, FIX_1_387039845);
		    tmp3 = MULTIPLY(d5, FIX_0_785694958);
		}
	    }
	} else {
	    if (d3) {
		if (d1) {
		    /* d1 != 0, d3 != 0, d5 == 0, d7 == 0 */
		    z5 = d1 + d3;
		    tmp3 = MULTIPLY(d1, FIX_0_211164243);
		    tmp2 = MULTIPLY(-d3, FIX_1_451774981);
		    z1 = MULTIPLY(d1, FIX_1_061594337);
		    z2 = MULTIPLY(-d3, FIX_2_172734803);
		    z4 = MULTIPLY(z5, FIX_0_785694958);
		    z5 = MULTIPLY(z5, FIX_1_175875602);
		    
		    tmp0 = z1 - z4;
		    tmp1 = z2 + z4;
		    tmp2 += z5;
		    tmp3 += z5;
		} else {
		    /* d1 == 0, d3 != 0, d5 == 0, d7 == 0 */
		    tmp0 = MULTIPLY(-d3, FIX_0_785694958);
		    tmp1 = MULTIPLY(-d3, FIX_1_387039845);
		    tmp2 = MULTIPLY(-d3, FIX_0_275899380);
		    tmp3 = MULTIPLY(d3, FIX_1_175875602);
		}
	    } else {
		if (d1) {
		    /* d1 != 0, d3 == 0, d5 == 0, d7 == 0 */
		    tmp0 = MULTIPLY(d1, FIX_0_275899380);
		    tmp1 = MULTIPLY(d1, FIX_0_785694958);
		    tmp2 = MULTIPLY(d1, FIX_1_175875602);
		    tmp3 = MULTIPLY(d1, FIX_1_387039845);
		} else {
		    /* d1 == 0, d3 == 0, d5 == 0, d7 == 0 */
		    tmp0 = tmp1 = tmp2 = tmp3 = 0;
		}
	    }
	}
    }

    /* Final output stage: inputs are tmp10..tmp13, tmp0..tmp3 */

    dataptr[DCTSIZE*0] = (DCTELEM) DESCALE(tmp10 + tmp3,
					   CONST_BITS+PASS1_BITS+3);
    dataptr[DCTSIZE*7] = (DCTELEM) DESCALE(tmp10 - tmp3,
					   CONST_BITS+PASS1_BITS+3);
    dataptr[DCTSIZE*1] = (DCTELEM) DESCALE(tmp11 + tmp2,
					   CONST_BITS+PASS1_BITS+3);
    dataptr[DCTSIZE*6] = (DCTELEM) DESCALE(tmp11 - tmp2,
					   CONST_BITS+PASS1_BITS+3);
    dataptr[DCTSIZE*2] = (DCTELEM) DESCALE(tmp12 + tmp1,
					   CONST_BITS+PASS1_BITS+3);
    dataptr[DCTSIZE*5] = (DCTELEM) DESCALE(tmp12 - tmp1,
					   CONST_BITS+PASS1_BITS+3);
    dataptr[DCTSIZE*3] = (DCTELEM) DESCALE(tmp13 + tmp0,
					   CONST_BITS+PASS1_BITS+3);
    dataptr[DCTSIZE*4] = (DCTELEM) DESCALE(tmp13 - tmp0,
					   CONST_BITS+PASS1_BITS+3);
    
    dataptr++;			/* advance pointer to next column */
  }
}


/* here is the reference one, in case of problems with the normal one */

/* idctref.c, Inverse Discrete Fourier Transform, double precision          */

/* Copyright (C) 1994, MPEG Software Simulation Group. All Rights Reserved. */

/*
 * Disclaimer of Warranty
 *
 * These software programs are available to the user without any license fee or
 * royalty on an "as is" basis.  The MPEG Software Simulation Group disclaims
 * any and all warranties, whether express, implied, or statuary, including any
 * implied warranties or merchantability or of fitness for a particular
 * purpose.  In no event shall the copyright-holder be liable for any
 * incidental, punitive, or consequential damages of any kind whatsoever
 * arising from the use of these programs.
 *
 * This disclaimer of warranty extends to the user of these programs and user's
 * customers, employees, agents, transferees, successors, and assigns.
 *
 * The MPEG Software Simulation Group does not represent or warrant that the
 * programs furnished hereunder are free of infringement of any third-party
 * patents.
 *
 * Commercial implementations of MPEG-1 and MPEG-2 video, including shareware,
 * are subject to royalty fees to patent holders.  Many of these patents are
 * general enough such that they are unavoidable regardless of implementation
 * design.
 *
 */

/*  Perform IEEE 1180 reference (64-bit floating point, separable 8x1
 *  direct matrix multiply) Inverse Discrete Cosine Transform
*/


/* Here we use math.h to generate constants.  Compiler results may
   vary a little */

#ifndef PI
#ifdef M_PI
#define PI M_PI
#else
#define PI 3.14159265358979323846
#endif
#endif

/* cosine transform matrix for 8x1 IDCT */
static double itrans_coef[8][8];

/* initialize DCT coefficient matrix */

void init_idctref()
{
  int freq, time;
  double scale;

  for (freq=0; freq < 8; freq++)
  {
    scale = (freq == 0) ? sqrt(0.125) : 0.5;
    for (time=0; time<8; time++)
      itrans_coef[freq][time] = scale*cos((PI/8.0)*freq*(time + 0.5));
  }
}

/* perform IDCT matrix multiply for 8x8 coefficient block */

void reference_rev_dct(block)
int16 *block;
{
  int i, j, k, v;
  double partial_product;
  double tmp[64];

  for (i=0; i<8; i++)
    for (j=0; j<8; j++)
    {
      partial_product = 0.0;

      for (k=0; k<8; k++)
        partial_product+= itrans_coef[k][j]*block[8*i+k];

      tmp[8*i+j] = partial_product;
    }

  /* Transpose operation is integrated into address mapping by switching 
     loop order of i and j */

  for (j=0; j<8; j++)
    for (i=0; i<8; i++)
    {
      partial_product = 0.0;

      for (k=0; k<8; k++)
        partial_product+= itrans_coef[k][i]*tmp[8*k+j];

      v = floor(partial_product+0.5);
      block[8*i+j] = (v<-256) ? -256 : ((v>255) ? 255 : v);
    }
}