aboutsummaryrefslogtreecommitdiffhomepage
path: root/mp3lib/layer2.c
blob: cad9a482b0d58088337c07df1edef79c13b8759c (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
/*
 * Modified for use with MPlayer, for details see the changelog at
 * http://svn.mplayerhq.hu/mplayer/trunk/
 * $Id$
 */

/* 
 * Mpeg Layer-2 audio decoder 
 * --------------------------
 * copyright (c) 1995 by Michael Hipp, All rights reserved. See also 'README'
 *
 */

//#include "mpg123.h"
#include "l2tables.h"

static int grp_3tab[32 * 3] = { 0, };   /* used: 27 */
static int grp_5tab[128 * 3] = { 0, };  /* used: 125 */
static int grp_9tab[1024 * 3] = { 0, }; /* used: 729 */

static real muls[27][64];	/* also used by layer 1 */

static void init_layer2(void)
{
  static double mulmul[27] = {
    0.0 , -2.0/3.0 , 2.0/3.0 ,
    2.0/7.0 , 2.0/15.0 , 2.0/31.0, 2.0/63.0 , 2.0/127.0 , 2.0/255.0 ,
    2.0/511.0 , 2.0/1023.0 , 2.0/2047.0 , 2.0/4095.0 , 2.0/8191.0 ,
    2.0/16383.0 , 2.0/32767.0 , 2.0/65535.0 ,
    -4.0/5.0 , -2.0/5.0 , 2.0/5.0, 4.0/5.0 ,
    -8.0/9.0 , -4.0/9.0 , -2.0/9.0 , 2.0/9.0 , 4.0/9.0 , 8.0/9.0 };
  static int base[3][9] = {
     { 1 , 0, 2 , } ,
     { 17, 18, 0 , 19, 20 , } ,
     { 21, 1, 22, 23, 0, 24, 25, 2, 26 } };
  int i,j,k,l,len;
  real *table;
  static int tablen[3] = { 3 , 5 , 9 };
  static int *itable,*tables[3] = { grp_3tab , grp_5tab , grp_9tab };

  for(i=0;i<3;i++)
  {
    itable = tables[i];
    len = tablen[i];
    for(j=0;j<len;j++)
      for(k=0;k<len;k++)
        for(l=0;l<len;l++)
        {
          *itable++ = base[i][l];
          *itable++ = base[i][k];
          *itable++ = base[i][j];
        }
  }

  for(k=0;k<27;k++)
  {
    double m=mulmul[k];
    table = muls[k];
    if(_has_mmx) 
    {
        for(j=3,i=0;i<63;i++,j--)
	  *table++ = 16384 * m * pow(2.0,(double) j / 3.0);
    }
    else
    for(j=3,i=0;i<63;i++,j--)
    {
      *table++ = m * pow(2.0,(double) j / 3.0);
    }
    *table++ = 0.0;
  }
}


static void II_step_one(unsigned int *bit_alloc,int *scale,struct frame *fr)
{
    int stereo = fr->stereo-1;
    int sblimit = fr->II_sblimit;
    int jsbound = fr->jsbound;
    int sblimit2 = fr->II_sblimit<<stereo;
    struct al_table *alloc1 = fr->alloc;
    int i;
    static unsigned int scfsi_buf[64];
    unsigned int *scfsi,*bita;
    int sc,step;

    bita = bit_alloc;
    if(stereo)
    {
      for (i=jsbound;i>0;i--,alloc1+=(1<<step))
      {
        *bita++ = (char) getbits(step=alloc1->bits);
        *bita++ = (char) getbits(step);
      }
      for (i=sblimit-jsbound;i>0;i--,alloc1+=(1<<step))
      {
        bita[0] = (char) getbits(step=alloc1->bits);
        bita[1] = bita[0];
        bita+=2;
      }
      bita = bit_alloc;
      scfsi=scfsi_buf;
      for (i=sblimit2;i>0;i--)
        if (*bita++)
          *scfsi++ = (char) getbits_fast(2);
    }
    else /* mono */
    {
      for (i=sblimit;i>0;i--,alloc1+=(1<<step))
        *bita++ = (char) getbits(step=alloc1->bits);
      bita = bit_alloc;
      scfsi=scfsi_buf;
      for (i=sblimit;i>0;i--)
        if (*bita++)
          *scfsi++ = (char) getbits_fast(2);
    }

    bita = bit_alloc;
    scfsi=scfsi_buf;
    for (i=sblimit2;i>0;i--) 
      if (*bita++)
        switch (*scfsi++) 
        {
          case 0: 
                *scale++ = getbits_fast(6);
                *scale++ = getbits_fast(6);
                *scale++ = getbits_fast(6);
                break;
          case 1 : 
                *scale++ = sc = getbits_fast(6);
                *scale++ = sc;
                *scale++ = getbits_fast(6);
                break;
          case 2: 
                *scale++ = sc = getbits_fast(6);
                *scale++ = sc;
                *scale++ = sc;
                break;
          default:              /* case 3 */
                *scale++ = getbits_fast(6);
                *scale++ = sc = getbits_fast(6);
                *scale++ = sc;
                break;
        }

}

static void II_step_two(unsigned int *bit_alloc,real fraction[2][4][SBLIMIT],int *scale,struct frame *fr,int x1)
{
    int i,j,k,ba;
    int stereo = fr->stereo;
    int sblimit = fr->II_sblimit;
    int jsbound = fr->jsbound;
    struct al_table *alloc2,*alloc1 = fr->alloc;
    unsigned int *bita=bit_alloc;
    int d1,step;

    for (i=0;i<jsbound;i++,alloc1+=(1<<step))
    {
      step = alloc1->bits;
      for (j=0;j<stereo;j++)
      {
        if ( (ba=*bita++) ) 
        {
          k=(alloc2 = alloc1+ba)->bits;
          if( (d1=alloc2->d) < 0) 
          {
            real cm=muls[k][scale[x1]];
            fraction[j][0][i] = ((real) ((int)getbits(k) + d1)) * cm;
            fraction[j][1][i] = ((real) ((int)getbits(k) + d1)) * cm;
            fraction[j][2][i] = ((real) ((int)getbits(k) + d1)) * cm;
          }        
          else 
          {
            static int *table[] = { 0,0,0,grp_3tab,0,grp_5tab,0,0,0,grp_9tab };
            unsigned int idx,*tab,m=scale[x1];
            idx = (unsigned int) getbits(k);
            tab = (unsigned int *) (table[d1] + idx + idx + idx);
            fraction[j][0][i] = muls[*tab++][m];
            fraction[j][1][i] = muls[*tab++][m];
            fraction[j][2][i] = muls[*tab][m];  
          }
          scale+=3;
        }
        else
          fraction[j][0][i] = fraction[j][1][i] = fraction[j][2][i] = 0.0;
      }
    }

    for (i=jsbound;i<sblimit;i++,alloc1+=(1<<step))
    {
      step = alloc1->bits;
      bita++;	/* channel 1 and channel 2 bitalloc are the same */
      if ( (ba=*bita++) )
      {
        k=(alloc2 = alloc1+ba)->bits;
        if( (d1=alloc2->d) < 0)
        {
          real cm;
          cm=muls[k][scale[x1+3]];
          fraction[1][0][i] = (fraction[0][0][i] = (real) ((int)getbits(k) + d1) ) * cm;
          fraction[1][1][i] = (fraction[0][1][i] = (real) ((int)getbits(k) + d1) ) * cm;
          fraction[1][2][i] = (fraction[0][2][i] = (real) ((int)getbits(k) + d1) ) * cm;
          cm=muls[k][scale[x1]];
          fraction[0][0][i] *= cm; fraction[0][1][i] *= cm; fraction[0][2][i] *= cm;
        }
        else
        {
          static int *table[] = { 0,0,0,grp_3tab,0,grp_5tab,0,0,0,grp_9tab };
          unsigned int idx,*tab,m1,m2;
          m1 = scale[x1]; m2 = scale[x1+3];
          idx = (unsigned int) getbits(k);
          tab = (unsigned int *) (table[d1] + idx + idx + idx);
          fraction[0][0][i] = muls[*tab][m1]; fraction[1][0][i] = muls[*tab++][m2];
          fraction[0][1][i] = muls[*tab][m1]; fraction[1][1][i] = muls[*tab++][m2];
          fraction[0][2][i] = muls[*tab][m1]; fraction[1][2][i] = muls[*tab][m2];
        }
        scale+=6;
      }
      else {
        fraction[0][0][i] = fraction[0][1][i] = fraction[0][2][i] =
        fraction[1][0][i] = fraction[1][1][i] = fraction[1][2][i] = 0.0;
      }
/* 
   should we use individual scalefac for channel 2 or
   is the current way the right one , where we just copy channel 1 to
   channel 2 ?? 
   The current 'strange' thing is, that we throw away the scalefac
   values for the second channel ...!!
-> changed .. now we use the scalefac values of channel one !! 
*/
    }

    if(sblimit > (fr->down_sample_sblimit) )
      sblimit = fr->down_sample_sblimit;

    for(i=sblimit;i<SBLIMIT;i++)
      for (j=0;j<stereo;j++)
        fraction[j][0][i] = fraction[j][1][i] = fraction[j][2][i] = 0.0;

}

static void II_select_table(struct frame *fr)
{
  static int translate[9][2][16] =
   { { { 0,2,2,2,2,2,2,0,0,0,1,1,1,1,1,0 } ,   /*44.1 stereo*/
       { 0,2,2,0,0,0,1,1,1,1,1,1,1,1,1,0 } } , /*44.1 mono*/
     { { 0,2,2,2,2,2,2,0,0,0,0,0,0,0,0,0 } ,   /*48 stereo*/
       { 0,2,2,0,0,0,0,0,0,0,0,0,0,0,0,0 } } , /*48 mono*/
     { { 0,3,3,3,3,3,3,0,0,0,1,1,1,1,1,0 } ,   /*32 stereo*/
       { 0,3,3,0,0,0,1,1,1,1,1,1,1,1,1,0 } } , /*32 mono*/
     { { 2,2,2,2,2,2,2,3,3,3,3,3,3,3,3,0 } ,   /*22.05 stereo*/
       { 2,2,2,3,3,3,3,3,3,3,3,3,3,3,3,0 } } , /*22.05 mono*/
     { { 2,2,2,2,2,2,2,3,3,3,3,3,3,3,3,0 } ,   /*24 stereo*/
       { 2,2,2,3,3,3,3,3,3,3,3,3,3,3,3,0 } } , /*24 mono*/
     { { 2,2,2,2,2,2,2,3,3,3,3,3,3,3,3,0 } ,   /*16 stereo*/
       { 2,2,2,3,3,3,3,3,3,3,3,3,3,3,3,0 } } , /*16 mono*/
     { { 2,2,2,2,2,2,2,3,3,3,3,3,3,3,3,0 } ,   /*11.025 stereo*/
       { 2,2,2,3,3,3,3,3,3,3,3,3,3,3,3,0 } } , /*11.025 mono*/
     { { 2,2,2,2,2,2,2,3,3,3,3,3,3,3,3,0 } ,   /*12 stereo*/
       { 2,2,2,3,3,3,3,3,3,3,3,3,3,3,3,0 } } , /*12 mono*/
     { { 2,2,2,2,2,2,2,3,3,3,3,3,3,3,3,0 } ,   /*8 stereo*/
       { 2,2,2,3,3,3,3,3,3,3,3,3,3,3,3,0 } }   /*8 mono*/
/*       0  48  64  96 128 192 256 384 */
/*        32  56  80 112 160 224 320  XX*/
       };

  int table,sblim;
  static struct al_table *tables[5] =
       { alloc_0, alloc_1, alloc_2, alloc_3 , alloc_4 };
  static int sblims[5] = { 27 , 30 , 8, 12 , 30 };

  if(fr->lsf)
    table = 4;
  else
    table = translate[fr->sampling_frequency][2-fr->stereo][fr->bitrate_index];
  sblim = sblims[table];

  fr->alloc      = tables[table];
  fr->II_sblimit = sblim;
}


static int do_layer2(struct frame *fr,int outmode)
{
  int clip=0;
  int i,j;
  int stereo = fr->stereo;
  real fraction[2][4][SBLIMIT]; /* pick_table clears unused subbands */
  unsigned int bit_alloc[64];
  int scale[192];
  int single = fr->single;

  II_select_table(fr);
  fr->jsbound = (fr->mode == MPG_MD_JOINT_STEREO) ?
     (fr->mode_ext<<2)+4 : fr->II_sblimit;

  if(stereo == 1 || single == 3)
    single = 0;

  II_step_one(bit_alloc, scale, fr);

  for (i=0;i<SCALE_BLOCK;i++) 
  {
    II_step_two(bit_alloc,fraction,scale,fr,i>>2);
    for (j=0;j<3;j++) 
    {
      if(single >= 0)
      {
        clip += (fr->synth_mono) (fraction[single][j],pcm_sample,&pcm_point);
      }
      else {
          int p1 = pcm_point;
          clip += (fr->synth) (fraction[0][j],0,pcm_sample,&p1);
          clip += (fr->synth) (fraction[1][j],1,pcm_sample,&pcm_point);
      }

//      if(pcm_point >= audiobufsize) audio_flush(outmode,ai);
    }
  }

  return clip;
}