jrevdct.c

MPEG2 PLAYER in linux

}

#else

/*
 *--------------------------------------------------------------
 *
 * j_rev_dct_sparse --
 *
 *  Performs the original inverse DCT on one block of 
 *  coefficients.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	None.
 *
 *--------------------------------------------------------------
 */
void
j_rev_dct_sparse (data, pos) 
     DCTBLOCK data;
     int pos;
{
  j_rev_dct(data);
}
#endif /* SPARSE_DCT */


#ifndef FIVE_DCT

#ifndef ORIG_DCT


/*
 *--------------------------------------------------------------
 *
 * j_rev_dct --
 *
 *  The inverse DCT function.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	None.
 *
 *--------------------------------------------------------------
 */
void
j_rev_dct (data)
     DCTBLOCK data;
{
  INT32 tmp0, tmp1, tmp2, tmp3;
  INT32 tmp10, tmp11, tmp12, tmp13;
  INT32 z1, z2, z3, z4, z5;
  INT32 d0, d1, d2, d3, d4, d5, d6, d7;
  register DCTELEM *dataptr;
  int rowctr;
  SHIFT_TEMPS
   
  /* Pass 1: process rows. */
  /* Note results are scaled up by sqrt(8) compared to a true IDCT; */
  /* furthermore, we scale the results by 2**PASS1_BITS. */

  dataptr = data;

  for (rowctr = DCTSIZE-1; rowctr >= 0; rowctr--) {
    /* Due to quantization, we will usually find that many of the input
     * coefficients are zero, especially the AC terms.  We can exploit this
     * by short-circuiting the IDCT calculation for any row in which all
     * the AC terms are zero.  In that case each output is equal to the
     * DC coefficient (with scale factor as needed).
     * With typical images and quantization tables, half or more of the
     * row DCT calculations can be simplified this way.
     */

    register int *idataptr = (int*)dataptr;
    d0 = dataptr[0];
    d1 = dataptr[1];
    if ((d1 == 0) && (idataptr[1] | idataptr[2] | idataptr[3]) == 0) {
      /* AC terms all zero */
      if (d0) {
	  /* Compute a 32 bit value to assign. */
	  DCTELEM dcval = (DCTELEM) (d0 << PASS1_BITS);
	  register int v = (dcval & 0xffff) | (dcval << 16);
	  
	  idataptr[0] = v;
	  idataptr[1] = v;
	  idataptr[2] = v;
	  idataptr[3] = v;
      }
      
      dataptr += DCTSIZE;	/* advance pointer to next row */
      continue;
    }
    d2 = dataptr[2];
    d3 = dataptr[3];
    d4 = dataptr[4];
    d5 = dataptr[5];
    d6 = dataptr[6];
    d7 = dataptr[7];

    /* Even part: reverse the even part of the forward DCT. */
    /* The rotator is sqrt(2)*c(-6). */
    if (d6) {
	if (d4) {
	    if (d2) {
		if (d0) {
		    /* d0 != 0, d2 != 0, d4 != 0, d6 != 0 */
		    z1 = MULTIPLY(d2 + d6, FIX(0.541196100));
		    tmp2 = z1 + MULTIPLY(d6, - FIX(1.847759065));
		    tmp3 = z1 + MULTIPLY(d2, FIX(0.765366865));

		    tmp0 = (d0 + d4) << CONST_BITS;
		    tmp1 = (d0 - d4) << CONST_BITS;

		    tmp10 = tmp0 + tmp3;
		    tmp13 = tmp0 - tmp3;
		    tmp11 = tmp1 + tmp2;
		    tmp12 = tmp1 - tmp2;
		} else {
		    /* d0 == 0, d2 != 0, d4 != 0, d6 != 0 */
		    z1 = MULTIPLY(d2 + d6, FIX(0.541196100));
		    tmp2 = z1 + MULTIPLY(d6, - FIX(1.847759065));
		    tmp3 = z1 + MULTIPLY(d2, FIX(0.765366865));

		    tmp0 = d4 << CONST_BITS;

		    tmp10 = tmp0 + tmp3;
		    tmp13 = tmp0 - tmp3;
		    tmp11 = tmp2 - tmp0;
		    tmp12 = -(tmp0 + tmp2);
		}
	    } else {
		if (d0) {
		    /* d0 != 0, d2 == 0, d4 != 0, d6 != 0 */
		    tmp2 = MULTIPLY(d6, - FIX2(1.306562965));
		    tmp3 = MULTIPLY(d6, FIX(0.541196100));

		    tmp0 = (d0 + d4) << CONST_BITS;
		    tmp1 = (d0 - d4) << CONST_BITS;

		    tmp10 = tmp0 + tmp3;
		    tmp13 = tmp0 - tmp3;
		    tmp11 = tmp1 + tmp2;
		    tmp12 = tmp1 - tmp2;
		} else {
		    /* d0 == 0, d2 == 0, d4 != 0, d6 != 0 */
		    tmp2 = MULTIPLY(d6, - FIX2(1.306562965));
		    tmp3 = MULTIPLY(d6, FIX(0.541196100));

		    tmp0 = d4 << CONST_BITS;

		    tmp10 = tmp0 + tmp3;
		    tmp13 = tmp0 - tmp3;
		    tmp11 = tmp2 - tmp0;
		    tmp12 = -(tmp0 + tmp2);
		}
	    }
	} else {
	    if (d2) {
		if (d0) {
		    /* d0 != 0, d2 != 0, d4 == 0, d6 != 0 */
		    z1 = MULTIPLY(d2 + d6, FIX(0.541196100));
		    tmp2 = z1 + MULTIPLY(d6, - FIX(1.847759065));
		    tmp3 = z1 + MULTIPLY(d2, FIX(0.765366865));

		    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 */
		    z1 = MULTIPLY(d2 + d6, FIX(0.541196100));
		    tmp2 = z1 + MULTIPLY(d6, - FIX(1.847759065));
		    tmp3 = z1 + MULTIPLY(d2, FIX(0.765366865));

		    tmp10 = tmp3;
		    tmp13 = -tmp3;
		    tmp11 = tmp2;
		    tmp12 = -tmp2;
		}
	    } else {
		if (d0) {
		    /* d0 != 0, d2 == 0, d4 == 0, d6 != 0 */
		    tmp2 = MULTIPLY(d6, - FIX2(1.306562965));
		    tmp3 = MULTIPLY(d6, FIX(0.541196100));

		    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(d6, - FIX2(1.306562965));
		    tmp3 = MULTIPLY(d6, FIX(0.541196100));

		    tmp10 = tmp3;
		    tmp13 = -tmp3;
		    tmp11 = tmp2;
		    tmp12 = -tmp2;
		}
	    }
	}
    } else {
	if (d4) {
	    if (d2) {
		if (d0) {
		    /* d0 != 0, d2 != 0, d4 != 0, d6 == 0 */
		    tmp2 = MULTIPLY(d2, FIX(0.541196100));
		    tmp3 = MULTIPLY(d2, (FIX(1.306562965) + .5));

		    tmp0 = (d0 + d4) << CONST_BITS;
		    tmp1 = (d0 - d4) << CONST_BITS;

		    tmp10 = tmp0 + tmp3;
		    tmp13 = tmp0 - tmp3;
		    tmp11 = tmp1 + tmp2;
		    tmp12 = tmp1 - tmp2;
		} else {
		    /* d0 == 0, d2 != 0, d4 != 0, d6 == 0 */
		    tmp2 = MULTIPLY(d2, FIX(0.541196100));
		    tmp3 = MULTIPLY(d2, (FIX(1.306562965) + .5));

		    tmp0 = d4 << CONST_BITS;

		    tmp10 = tmp0 + tmp3;
		    tmp13 = tmp0 - tmp3;
		    tmp11 = tmp2 - tmp0;
		    tmp12 = -(tmp0 + tmp2);
		}
	    } else {
		if (d0) {
		    /* d0 != 0, d2 == 0, d4 != 0, d6 == 0 */
		    tmp10 = tmp13 = (d0 + d4) << CONST_BITS;
		    tmp11 = tmp12 = (d0 - d4) << CONST_BITS;
		} else {
		    /* d0 == 0, d2 == 0, d4 != 0, d6 == 0 */
		    tmp10 = tmp13 = d4 << CONST_BITS;
		    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) + .5));

		    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) + .5));

		    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 */
		    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;
		    z4 = d5 + d1;
		    z5 = MULTIPLY(d7 + 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 */
		    z5 = MULTIPLY(d7 + d5, FIX(1.175875602));

		    tmp0 = MULTIPLY(d7, - FIX2(0.601344887));
		    tmp1 = MULTIPLY(d5, - FIX2(0.509795578));
		    z1 = MULTIPLY(d7, - FIX(0.899976223));
		    z3 = MULTIPLY(d7, - FIX(1.961570560));
		    z2 = MULTIPLY(d5, - FIX(2.562915447));
		    z4 = MULTIPLY(d5, - FIX(0.390180644));
		    
		    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;
		    z5 = MULTIPLY(z3, FIX(1.175875602));
		    
		    tmp0 = MULTIPLY(d7, - FIX2(0.601344887));
		    tmp2 = MULTIPLY(d3, FIX(0.509795579));
		    z1 = MULTIPLY(d7, - FIX(0.899976223));
		    z2 = MULTIPLY(d3, - FIX(2.562915447));
		    z3 = MULTIPLY(z3, - FIX2(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));

		    tmp0 = MULTIPLY(d7, - FIX2(1.662939224));
		    tmp3 = MULTIPLY(d1, FIX2(1.111140466));
		    z1 = MULTIPLY(z1, FIX2(0.275899379));
		    z3 = MULTIPLY(d7, - FIX(1.961570560));