layer3.c

神龙卡开发原代码

/* 
 * Mpeg Layer-3 audio decoder 
 * --------------------------
 * copyright (c) 1995,1996,1997 by Michael Hipp.
 * All rights reserved. See also 'README'
 */ 

#include <stdlib.h>
#include "mpg123.h"
#include "mpglib.h"
#include "huffman.h"

extern struct mpstr *gmp;

#define MPEG1


static real ispow[8207];
static real aa_ca[8],aa_cs[8];
static real COS1[12][6];
static real win[4][36];
static real win1[4][36];
static real gainpow2[256+118+4];
static real COS9[9];
static real COS6_1,COS6_2;
static real tfcos36[9];
static real tfcos12[3];

struct bandInfoStruct {
  short longIdx[23];
  short longDiff[22];
  short shortIdx[14];
  short shortDiff[13];
};

int longLimit[9][23];
int shortLimit[9][14];

struct bandInfoStruct bandInfo[9] = { 

/* MPEG 1.0 */
 { {0,4,8,12,16,20,24,30,36,44,52,62,74, 90,110,134,162,196,238,288,342,418,576},
   {4,4,4,4,4,4,6,6,8, 8,10,12,16,20,24,28,34,42,50,54, 76,158},
   {0,4*3,8*3,12*3,16*3,22*3,30*3,40*3,52*3,66*3, 84*3,106*3,136*3,192*3},
   {4,4,4,4,6,8,10,12,14,18,22,30,56} } ,

 { {0,4,8,12,16,20,24,30,36,42,50,60,72, 88,106,128,156,190,230,276,330,384,576},
   {4,4,4,4,4,4,6,6,6, 8,10,12,16,18,22,28,34,40,46,54, 54,192},
   {0,4*3,8*3,12*3,16*3,22*3,28*3,38*3,50*3,64*3, 80*3,100*3,126*3,192*3},
   {4,4,4,4,6,6,10,12,14,16,20,26,66} } ,

 { {0,4,8,12,16,20,24,30,36,44,54,66,82,102,126,156,194,240,296,364,448,550,576} ,
   {4,4,4,4,4,4,6,6,8,10,12,16,20,24,30,38,46,56,68,84,102, 26} ,
   {0,4*3,8*3,12*3,16*3,22*3,30*3,42*3,58*3,78*3,104*3,138*3,180*3,192*3} ,
   {4,4,4,4,6,8,12,16,20,26,34,42,12} }  ,

/* MPEG 2.0 */
 { {0,6,12,18,24,30,36,44,54,66,80,96,116,140,168,200,238,284,336,396,464,522,576},
   {6,6,6,6,6,6,8,10,12,14,16,20,24,28,32,38,46,52,60,68,58,54 } ,
   {0,4*3,8*3,12*3,18*3,24*3,32*3,42*3,56*3,74*3,100*3,132*3,174*3,192*3} ,
   {4,4,4,6,6,8,10,14,18,26,32,42,18 } } ,

 { {0,6,12,18,24,30,36,44,54,66,80,96,114,136,162,194,232,278,330,394,464,540,576},
   {6,6,6,6,6,6,8,10,12,14,16,18,22,26,32,38,46,52,64,70,76,36 } ,
   {0,4*3,8*3,12*3,18*3,26*3,36*3,48*3,62*3,80*3,104*3,136*3,180*3,192*3} ,
   {4,4,4,6,8,10,12,14,18,24,32,44,12 } } ,

 { {0,6,12,18,24,30,36,44,54,66,80,96,116,140,168,200,238,284,336,396,464,522,576},
   {6,6,6,6,6,6,8,10,12,14,16,20,24,28,32,38,46,52,60,68,58,54 },
   {0,4*3,8*3,12*3,18*3,26*3,36*3,48*3,62*3,80*3,104*3,134*3,174*3,192*3},
   {4,4,4,6,8,10,12,14,18,24,30,40,18 } } ,
/* MPEG 2.5 */
 { {0,6,12,18,24,30,36,44,54,66,80,96,116,140,168,200,238,284,336,396,464,522,576} ,
   {6,6,6,6,6,6,8,10,12,14,16,20,24,28,32,38,46,52,60,68,58,54},
   {0,12,24,36,54,78,108,144,186,240,312,402,522,576},
   {4,4,4,6,8,10,12,14,18,24,30,40,18} },
 { {0,6,12,18,24,30,36,44,54,66,80,96,116,140,168,200,238,284,336,396,464,522,576} ,
   {6,6,6,6,6,6,8,10,12,14,16,20,24,28,32,38,46,52,60,68,58,54},
   {0,12,24,36,54,78,108,144,186,240,312,402,522,576},
   {4,4,4,6,8,10,12,14,18,24,30,40,18} },
 { {0,12,24,36,48,60,72,88,108,132,160,192,232,280,336,400,476,566,568,570,572,574,576},
   {12,12,12,12,12,12,16,20,24,28,32,40,48,56,64,76,90,2,2,2,2,2},
   {0, 24, 48, 72,108,156,216,288,372,480,486,492,498,576},
   {8,8,8,12,16,20,24,28,36,2,2,2,26} } ,
};

static int mapbuf0[9][152];
static int mapbuf1[9][156];
static int mapbuf2[9][44];
static int *map[9][3];
static int *mapend[9][3];

static unsigned int n_slen2[512]; /* MPEG 2.0 slen for 'normal' mode */
static unsigned int i_slen2[256]; /* MPEG 2.0 slen for intensity stereo */

static real tan1_1[16],tan2_1[16],tan1_2[16],tan2_2[16];
static real pow1_1[2][16],pow2_1[2][16],pow1_2[2][16],pow2_2[2][16];

/* 
 * init tables for layer-3 
 */
void init_layer3(int down_sample_sblimit)
{
  int i,j,k,l;

  for(i=-256;i<118+4;i++)
    gainpow2[i+256] = pow((double)2.0,-0.25 * (double) (i+210) );

  for(i=0;i<8207;i++)
    ispow[i] = pow((double)i,(double)4.0/3.0);

  for (i=0;i<8;i++)
  {
    static double Ci[8]={-0.6,-0.535,-0.33,-0.185,-0.095,-0.041,-0.0142,-0.0037};
    double sq=sqrt(1.0+Ci[i]*Ci[i]);
    aa_cs[i] = 1.0/sq;
    aa_ca[i] = Ci[i]/sq;
  }

  for(i=0;i<18;i++)
  {
    win[0][i]    = win[1][i]    = 0.5 * sin( M_PI / 72.0 * (double) (2*(i+0) +1) ) / cos ( M_PI * (double) (2*(i+0) +19) / 72.0 );
    win[0][i+18] = win[3][i+18] = 0.5 * sin( M_PI / 72.0 * (double) (2*(i+18)+1) ) / cos ( M_PI * (double) (2*(i+18)+19) / 72.0 );
  }
  for(i=0;i<6;i++)
  {
    win[1][i+18] = 0.5 / cos ( M_PI * (double) (2*(i+18)+19) / 72.0 );
    win[3][i+12] = 0.5 / cos ( M_PI * (double) (2*(i+12)+19) / 72.0 );
    win[1][i+24] = 0.5 * sin( M_PI / 24.0 * (double) (2*i+13) ) / cos ( M_PI * (double) (2*(i+24)+19) / 72.0 );
    win[1][i+30] = win[3][i] = 0.0;
    win[3][i+6 ] = 0.5 * sin( M_PI / 24.0 * (double) (2*i+1) )  / cos ( M_PI * (double) (2*(i+6 )+19) / 72.0 );
  }

  for(i=0;i<9;i++)
    COS9[i] = cos( M_PI / 18.0 * (double) i);

  for(i=0;i<9;i++)
    tfcos36[i] = 0.5 / cos ( M_PI * (double) (i*2+1) / 36.0 );
  for(i=0;i<3;i++)
    tfcos12[i] = 0.5 / cos ( M_PI * (double) (i*2+1) / 12.0 );

  COS6_1 = cos( M_PI / 6.0 * (double) 1);
  COS6_2 = cos( M_PI / 6.0 * (double) 2);

  for(i=0;i<12;i++)
  {
    win[2][i]  = 0.5 * sin( M_PI / 24.0 * (double) (2*i+1) ) / cos ( M_PI * (double) (2*i+7) / 24.0 );
    for(j=0;j<6;j++)
      COS1[i][j] = cos( M_PI / 24.0 * (double) ((2*i+7)*(2*j+1)) );
  }

  for(j=0;j<4;j++) {
    static int len[4] = { 36,36,12,36 };
    for(i=0;i<len[j];i+=2)
      win1[j][i] = + win[j][i];
    for(i=1;i<len[j];i+=2)
      win1[j][i] = - win[j][i];
  }

  for(i=0;i<16;i++)
  {
    double t = tan( (double) i * M_PI / 12.0 );
    tan1_1[i] = t / (1.0+t);
    tan2_1[i] = 1.0 / (1.0 + t);
    tan1_2[i] = M_SQRT2 * t / (1.0+t);
    tan2_2[i] = M_SQRT2 / (1.0 + t);

    for(j=0;j<2;j++) {
      double base = pow(2.0,-0.25*(j+1.0));
      double p1=1.0,p2=1.0;
      if(i > 0) {
        if( i & 1 )
          p1 = pow(base,(i+1.0)*0.5);
        else
          p2 = pow(base,i*0.5);
      }
      pow1_1[j][i] = p1;
      pow2_1[j][i] = p2;
      pow1_2[j][i] = M_SQRT2 * p1;
      pow2_2[j][i] = M_SQRT2 * p2;
    }
  }

  for(j=0;j<9;j++)
  {
   struct bandInfoStruct *bi = &bandInfo[j];
   int *mp;
   int cb,lwin;
   short *bdf;

   mp = map[j][0] = mapbuf0[j];
   bdf = bi->longDiff;
   for(i=0,cb = 0; cb < 8 ; cb++,i+=*bdf++) {
     *mp++ = (*bdf) >> 1;
     *mp++ = i;
     *mp++ = 3;
     *mp++ = cb;
   }
   bdf = bi->shortDiff+3;
   for(cb=3;cb<13;cb++) {
     int l = (*bdf++) >> 1;
     for(lwin=0;lwin<3;lwin++) {
       *mp++ = l;
       *mp++ = i + lwin;
       *mp++ = lwin;
       *mp++ = cb;
     }
     i += 6*l;
   }
   mapend[j][0] = mp;

   mp = map[j][1] = mapbuf1[j];
   bdf = bi->shortDiff+0;
   for(i=0,cb=0;cb<13;cb++) {
     int l = (*bdf++) >> 1;
     for(lwin=0;lwin<3;lwin++) {
       *mp++ = l;
       *mp++ = i + lwin;
       *mp++ = lwin;
       *mp++ = cb;
     }
     i += 6*l;
   }
   mapend[j][1] = mp;

   mp = map[j][2] = mapbuf2[j];
   bdf = bi->longDiff;
   for(cb = 0; cb < 22 ; cb++) {
     *mp++ = (*bdf++) >> 1;
     *mp++ = cb;
   }
   mapend[j][2] = mp;

  }

  for(j=0;j<9;j++) {
    for(i=0;i<23;i++) {
      longLimit[j][i] = (bandInfo[j].longIdx[i] - 1 + 8) / 18 + 1;
      if(longLimit[j][i] > (down_sample_sblimit) )
        longLimit[j][i] = down_sample_sblimit;
    }
    for(i=0;i<14;i++) {
      shortLimit[j][i] = (bandInfo[j].shortIdx[i] - 1) / 18 + 1;
      if(shortLimit[j][i] > (down_sample_sblimit) )
        shortLimit[j][i] = down_sample_sblimit;
    }
  }

  for(i=0;i<5;i++) {
    for(j=0;j<6;j++) {
      for(k=0;k<6;k++) {
        int n = k + j * 6 + i * 36;
        i_slen2[n] = i|(j<<3)|(k<<6)|(3<<12);
      }
    }
  }
  for(i=0;i<4;i++) {
    for(j=0;j<4;j++) {
      for(k=0;k<4;k++) {
        int n = k + j * 4 + i * 16;
        i_slen2[n+180] = i|(j<<3)|(k<<6)|(4<<12);
      }
    }
  }
  for(i=0;i<4;i++) {
    for(j=0;j<3;j++) {
      int n = j + i * 3;
      i_slen2[n+244] = i|(j<<3) | (5<<12);
      n_slen2[n+500] = i|(j<<3) | (2<<12) | (1<<15);
    }
  }

  for(i=0;i<5;i++) {
    for(j=0;j<5;j++) {
      for(k=0;k<4;k++) {
        for(l=0;l<4;l++) {
          int n = l + k * 4 + j * 16 + i * 80;
          n_slen2[n] = i|(j<<3)|(k<<6)|(l<<9)|(0<<12);
        }
      }
    }
  }
  for(i=0;i<5;i++) {
    for(j=0;j<5;j++) {
      for(k=0;k<4;k++) {
        int n = k + j * 4 + i * 20;
        n_slen2[n+400] = i|(j<<3)|(k<<6)|(1<<12);
      }
    }
  }
}

/*
 * read additional side information
 */
#ifdef MPEG1 
static void III_get_side_info_1(struct III_sideinfo *si,int stereo,
 int ms_stereo,long sfreq,int single)
{
   int ch, gr;
   int powdiff = (single == 3) ? 4 : 0;

   si->main_data_begin = MP3getbits(9);
   if (stereo == 1)
     si->private_bits = MP3getbits_fast(5);
   else 
     si->private_bits = MP3getbits_fast(3);

   for (ch=0; ch<stereo; ch++) {
       si->ch[ch].gr[0].scfsi = -1;
       si->ch[ch].gr[1].scfsi = MP3getbits_fast(4);
   }

   for (gr=0; gr<2; gr++) 
   {
     for (ch=0; ch<stereo; ch++) 
     {
       register struct gr_info_s *gr_info = &(si->ch[ch].gr[gr]);

       gr_info->part2_3_length = MP3getbits(12);
       gr_info->big_values = MP3getbits_fast(9);
       if(gr_info->big_values > 288) {
          //fprintf(stderr,"big_values too large!\n");
          gr_info->big_values = 288;
       }
       gr_info->pow2gain = gainpow2+256 - MP3getbits_fast(8) + powdiff;
       if(ms_stereo)
         gr_info->pow2gain += 2;
       gr_info->scalefac_compress = MP3getbits_fast(4);
/* window-switching flag == 1 for block_Type != 0 .. and block-type == 0 -> win-sw-flag = 0 */
       if(get1bit())
       {
         int i;
         gr_info->block_type = MP3getbits_fast(2);
         gr_info->mixed_block_flag = get1bit();
         gr_info->table_select[0] = MP3getbits_fast(5);
         gr_info->table_select[1] = MP3getbits_fast(5);
         /*
          * table_select[2] not needed, because there is no region2,
          * but to satisfy some verifications tools we set it either.
          */
         gr_info->table_select[2] = 0;
         for(i=0;i<3;i++)
           gr_info->full_gain[i] = gr_info->pow2gain + (MP3getbits_fast(3)<<3);

         if(gr_info->block_type == 0) {
           fprintf(stderr,"Blocktype == 0 and window-switching == 1 not allowed ... exiting\n");
           exit(1);
         }
         /* region_count/start parameters are implicit in this case. */
         gr_info->region1start = 36>>1;
         gr_info->region2start = 576>>1;
       }
       else
       {
         int i,r0c,r1c;
         for (i=0; i<3; i++)
           gr_info->table_select[i] = MP3getbits_fast(5);
         r0c = MP3getbits_fast(4);
         r1c = MP3getbits_fast(3);
         gr_info->region1start = bandInfo[sfreq].longIdx[r0c+1] >> 1 ;
         gr_info->region2start = bandInfo[sfreq].longIdx[r0c+1+r1c+1] >> 1;
         gr_info->block_type = 0;
         gr_info->mixed_block_flag = 0;
       }
       gr_info->preflag = get1bit();
       gr_info->scalefac_scale = get1bit();
       gr_info->count1table_select = get1bit();
     }
   }
}
#endif

/*
 * Side Info for MPEG 2.0 / LSF
 */
static void III_get_side_info_2(struct III_sideinfo *si,int stereo,
 int ms_stereo,long sfreq,int single)
{
   int ch;
   int powdiff = (single == 3) ? 4 : 0;

   si->main_data_begin = MP3getbits(8);
   if (stereo == 1)
     si->private_bits = get1bit();
   else
     si->private_bits = MP3getbits_fast(2);

   for (ch=0; ch<stereo; ch++)
   {
       register struct gr_info_s *gr_info = &(si->ch[ch].gr[0]);

       gr_info->part2_3_length = MP3getbits(12);
       gr_info->big_values = MP3getbits_fast(9);
       if(gr_info->big_values > 288) {
         //fprintf(stderr,"big_values too large!\n");
         gr_info->big_values = 288;
       }
       gr_info->pow2gain = gainpow2+256 - MP3getbits_fast(8) + powdiff;
       if(ms_stereo)
         gr_info->pow2gain += 2;
       gr_info->scalefac_compress = MP3getbits(9);
/* window-switching flag == 1 for block_Type != 0 .. and block-type == 0 -> win-sw-flag = 0 */
       if(get1bit())
       {
         int i;
         gr_info->block_type = MP3getbits_fast(2);
         gr_info->mixed_block_flag = get1bit();
         gr_info->table_select[0] = MP3getbits_fast(5);
         gr_info->table_select[1] = MP3getbits_fast(5);
         /*
          * table_select[2] not needed, because there is no region2,
          * but to satisfy some verifications tools we set it either.
          */
         gr_info->table_select[2] = 0;
         for(i=0;i<3;i++)
           gr_info->full_gain[i] = gr_info->pow2gain + (MP3getbits_fast(3)<<3);

         if(gr_info->block_type == 0) {
           fprintf(stderr,"Blocktype == 0 and window-switching == 1 not allowed ... exiting\n");
           exit(1);
         }
         /* region_count/start parameters are implicit in this case. */
/* check this again! */
         if(gr_info->block_type == 2)
           gr_info->region1start = 36>>1;
         else if(sfreq == 8)
/* check this for 2.5 and sfreq=8 */
           gr_info->region1start = 108>>1;
         else
           gr_info->region1start = 54>>1;
         gr_info->region2start = 576>>1;
       }
       else
       {
         int i,r0c,r1c;
         for (i=0; i<3; i++)
           gr_info->table_select[i] = MP3getbits_fast(5);
         r0c = MP3getbits_fast(4);
         r1c = MP3getbits_fast(3);
         gr_info->region1start = bandInfo[sfreq].longIdx[r0c+1] >> 1 ;
         gr_info->region2start = bandInfo[sfreq].longIdx[r0c+1+r1c+1] >> 1;
         gr_info->block_type = 0;
         gr_info->mixed_block_flag = 0;
       }
       gr_info->scalefac_scale = get1bit();
       gr_info->count1table_select = get1bit();
   }
}

/*
 * read scalefactors
 */
#ifdef MPEG1
static int III_get_scale_factors_1(int *scf,struct gr_info_s *gr_info)
{
   static unsigned char slen[2][16] = {
     {0, 0, 0, 0, 3, 1, 1, 1, 2, 2, 2, 3, 3, 3, 4, 4},
     {0, 1, 2, 3, 0, 1, 2, 3, 1, 2, 3, 1, 2, 3, 2, 3}
   };
   int numbits;
   int num0 = slen[0][gr_info->scalefac_compress];
   int num1 = slen[1][gr_info->scalefac_compress];

    if (gr_info->block_type == 2)
    {
      int i=18;
      numbits = (num0 + num1) * 18;

      if (gr_info->mixed_block_flag) {
         for (i=8;i;i--)
           *scf++ = MP3getbits_fast(num0);
         i = 9;
         numbits -= num0; /* num0 * 17 + num1 * 18 */
      }

      for (;i;i--)
        *scf++ = MP3getbits_fast(num0);
      for (i = 18; i; i--)
        *scf++ = MP3getbits_fast(num1);
      *scf++ = 0; *scf++ = 0; *scf++ = 0; /* short[13][0..2] = 0 */
    }
    else
    {
      int i;
      int scfsi = gr_info->scfsi;

      if(scfsi < 0) { /* scfsi < 0 => granule == 0 */
         for(i=11;i;i--)
           *scf++ = MP3getbits_fast(num0);
         for(i=10;i;i--)
           *scf++ = MP3getbits_fast(num1);
         numbits = (num0 + num1) * 10 + num0;
      }
      else {
        numbits = 0;
        if(!(scfsi & 0x8)) {
          for (i=6;i;i--)
            *scf++ = MP3getbits_fast(num0);
          numbits += num0 * 6;
        }
        else {
          *scf++ = 0; *scf++ = 0; *scf++ = 0;  /* set to ZERO necessary? */
          *scf++ = 0; *scf++ = 0; *scf++ = 0;
        }