ReactOS Development > Doxygen

00001 /*
00002     dct64.c: DCT64, the plain C version
00003 
00004     copyright ?-2006 by the mpg123 project - free software under the terms of the LGPL 2.1
00005     see COPYING and AUTHORS files in distribution or http://mpg123.org
00006     initially written by Michael Hipp
00007 */
00008 
00009 /*
00010  * Discrete Cosine Tansform (DCT) for subband synthesis
00011  *
00012  * -funroll-loops (for gcc) will remove the loops for better performance
00013  * using loops in the source-code enhances readabillity
00014  *
00015  *
00016  * TODO: write an optimized version for the down-sampling modes
00017  *       (in these modes the bands 16-31 (2:1) or 8-31 (4:1) are zero 
00018  */
00019 
00020 #include "mpg123lib_intern.h"
00021 
00022 void dct64(real *out0,real *out1,real *samples)
00023 {
00024   real bufs[64];
00025 
00026  {
00027   register int i,j;
00028   register real *b1,*b2,*bs,*costab;
00029 
00030   b1 = samples;
00031   bs = bufs;
00032   costab = pnts[0]+16;
00033   b2 = b1 + 32;
00034 
00035   for(i=15;i>=0;i--)
00036     *bs++ = (*b1++ + *--b2); 
00037   for(i=15;i>=0;i--)
00038     *bs++ = REAL_MUL((*--b2 - *b1++), *--costab);
00039 
00040   b1 = bufs;
00041   costab = pnts[1]+8;
00042   b2 = b1 + 16;
00043 
00044   {
00045     for(i=7;i>=0;i--)
00046       *bs++ = (*b1++ + *--b2); 
00047     for(i=7;i>=0;i--)
00048       *bs++ = REAL_MUL((*--b2 - *b1++), *--costab);
00049     b2 += 32;
00050     costab += 8;
00051     for(i=7;i>=0;i--)
00052       *bs++ = (*b1++ + *--b2); 
00053     for(i=7;i>=0;i--)
00054       *bs++ = REAL_MUL((*b1++ - *--b2), *--costab);
00055     b2 += 32;
00056   }
00057 
00058   bs = bufs;
00059   costab = pnts[2];
00060   b2 = b1 + 8;
00061 
00062   for(j=2;j;j--)
00063   {
00064     for(i=3;i>=0;i--)
00065       *bs++ = (*b1++ + *--b2); 
00066     for(i=3;i>=0;i--)
00067       *bs++ = REAL_MUL((*--b2 - *b1++), costab[i]);
00068     b2 += 16;
00069     for(i=3;i>=0;i--)
00070       *bs++ = (*b1++ + *--b2); 
00071     for(i=3;i>=0;i--)
00072       *bs++ = REAL_MUL((*b1++ - *--b2), costab[i]);
00073     b2 += 16;
00074   }
00075 
00076   b1 = bufs;
00077   costab = pnts[3];
00078   b2 = b1 + 4;
00079 
00080   for(j=4;j;j--)
00081   {
00082     *bs++ = (*b1++ + *--b2); 
00083     *bs++ = (*b1++ + *--b2);
00084     *bs++ = REAL_MUL((*--b2 - *b1++), costab[1]);
00085     *bs++ = REAL_MUL((*--b2 - *b1++), costab[0]);
00086     b2 += 8;
00087     *bs++ = (*b1++ + *--b2); 
00088     *bs++ = (*b1++ + *--b2);
00089     *bs++ = REAL_MUL((*b1++ - *--b2), costab[1]);
00090     *bs++ = REAL_MUL((*b1++ - *--b2), costab[0]);
00091     b2 += 8;
00092   }
00093   bs = bufs;
00094   costab = pnts[4];
00095 
00096   for(j=8;j;j--)
00097   {
00098     real v0,v1;
00099     v0=*b1++; v1 = *b1++;
00100     *bs++ = (v0 + v1);
00101     *bs++ = REAL_MUL((v0 - v1), (*costab));
00102     v0=*b1++; v1 = *b1++;
00103     *bs++ = (v0 + v1);
00104     *bs++ = REAL_MUL((v1 - v0), (*costab));
00105   }
00106 
00107  }
00108 
00109 
00110  {
00111   register real *b1;
00112   register int i;
00113 
00114   for(b1=bufs,i=8;i;i--,b1+=4)
00115     b1[2] += b1[3];
00116 
00117   for(b1=bufs,i=4;i;i--,b1+=8)
00118   {
00119     b1[4] += b1[6];
00120     b1[6] += b1[5];
00121     b1[5] += b1[7];
00122   }
00123 
00124   for(b1=bufs,i=2;i;i--,b1+=16)
00125   {
00126     b1[8]  += b1[12];
00127     b1[12] += b1[10];
00128     b1[10] += b1[14];
00129     b1[14] += b1[9];
00130     b1[9]  += b1[13];
00131     b1[13] += b1[11];
00132     b1[11] += b1[15];
00133   }
00134  }
00135 
00136 
00137   out0[0x10*16] = REAL_SCALE_DCT64(bufs[0]);
00138   out0[0x10*15] = REAL_SCALE_DCT64(bufs[16+0]  + bufs[16+8]);
00139   out0[0x10*14] = REAL_SCALE_DCT64(bufs[8]);
00140   out0[0x10*13] = REAL_SCALE_DCT64(bufs[16+8]  + bufs[16+4]);
00141   out0[0x10*12] = REAL_SCALE_DCT64(bufs[4]);
00142   out0[0x10*11] = REAL_SCALE_DCT64(bufs[16+4]  + bufs[16+12]);
00143   out0[0x10*10] = REAL_SCALE_DCT64(bufs[12]);
00144   out0[0x10* 9] = REAL_SCALE_DCT64(bufs[16+12] + bufs[16+2]);
00145   out0[0x10* 8] = REAL_SCALE_DCT64(bufs[2]);
00146   out0[0x10* 7] = REAL_SCALE_DCT64(bufs[16+2]  + bufs[16+10]);
00147   out0[0x10* 6] = REAL_SCALE_DCT64(bufs[10]);
00148   out0[0x10* 5] = REAL_SCALE_DCT64(bufs[16+10] + bufs[16+6]);
00149   out0[0x10* 4] = REAL_SCALE_DCT64(bufs[6]);
00150   out0[0x10* 3] = REAL_SCALE_DCT64(bufs[16+6]  + bufs[16+14]);
00151   out0[0x10* 2] = REAL_SCALE_DCT64(bufs[14]);
00152   out0[0x10* 1] = REAL_SCALE_DCT64(bufs[16+14] + bufs[16+1]);
00153   out0[0x10* 0] = REAL_SCALE_DCT64(bufs[1]);
00154 
00155   out1[0x10* 0] = REAL_SCALE_DCT64(bufs[1]);
00156   out1[0x10* 1] = REAL_SCALE_DCT64(bufs[16+1]  + bufs[16+9]);
00157   out1[0x10* 2] = REAL_SCALE_DCT64(bufs[9]);
00158   out1[0x10* 3] = REAL_SCALE_DCT64(bufs[16+9]  + bufs[16+5]);
00159   out1[0x10* 4] = REAL_SCALE_DCT64(bufs[5]);
00160   out1[0x10* 5] = REAL_SCALE_DCT64(bufs[16+5]  + bufs[16+13]);
00161   out1[0x10* 6] = REAL_SCALE_DCT64(bufs[13]);
00162   out1[0x10* 7] = REAL_SCALE_DCT64(bufs[16+13] + bufs[16+3]);
00163   out1[0x10* 8] = REAL_SCALE_DCT64(bufs[3]);
00164   out1[0x10* 9] = REAL_SCALE_DCT64(bufs[16+3]  + bufs[16+11]);
00165   out1[0x10*10] = REAL_SCALE_DCT64(bufs[11]);
00166   out1[0x10*11] = REAL_SCALE_DCT64(bufs[16+11] + bufs[16+7]);
00167   out1[0x10*12] = REAL_SCALE_DCT64(bufs[7]);
00168   out1[0x10*13] = REAL_SCALE_DCT64(bufs[16+7]  + bufs[16+15]);
00169   out1[0x10*14] = REAL_SCALE_DCT64(bufs[15]);
00170   out1[0x10*15] = REAL_SCALE_DCT64(bufs[16+15]);
00171 
00172 }
00173 
00174
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