|
261
|
1 /*
|
|
|
2 * Mpeg Layer-2 audio decoder
|
|
|
3 * --------------------------
|
|
|
4 * copyright (c) 1995 by Michael Hipp, All rights reserved. See also 'README'
|
|
|
5 *
|
|
|
6 */
|
|
|
7
|
|
|
8 #include "mpg123_sdlsound.h"
|
|
|
9 #include "l2tables.h"
|
|
|
10
|
|
|
11 static int grp_3tab[32 * 3] = { 0, }; /* used: 27 */
|
|
|
12 static int grp_5tab[128 * 3] = { 0, }; /* used: 125 */
|
|
|
13 static int grp_9tab[1024 * 3] = { 0, }; /* used: 729 */
|
|
|
14
|
|
|
15 real muls[27][64]; /* also used by layer 1 */
|
|
|
16
|
|
|
17 void init_layer2(void)
|
|
|
18 {
|
|
|
19 static double mulmul[27] = {
|
|
|
20 0.0 , -2.0/3.0 , 2.0/3.0 ,
|
|
|
21 2.0/7.0 , 2.0/15.0 , 2.0/31.0, 2.0/63.0 , 2.0/127.0 , 2.0/255.0 ,
|
|
|
22 2.0/511.0 , 2.0/1023.0 , 2.0/2047.0 , 2.0/4095.0 , 2.0/8191.0 ,
|
|
|
23 2.0/16383.0 , 2.0/32767.0 , 2.0/65535.0 ,
|
|
|
24 -4.0/5.0 , -2.0/5.0 , 2.0/5.0, 4.0/5.0 ,
|
|
|
25 -8.0/9.0 , -4.0/9.0 , -2.0/9.0 , 2.0/9.0 , 4.0/9.0 , 8.0/9.0 };
|
|
|
26 static int base[3][9] = {
|
|
|
27 { 1 , 0, 2 , } ,
|
|
|
28 { 17, 18, 0 , 19, 20 , } ,
|
|
|
29 { 21, 1, 22, 23, 0, 24, 25, 2, 26 } };
|
|
|
30 int i,j,k,l,len;
|
|
|
31 real *table;
|
|
|
32 static int tablen[3] = { 3 , 5 , 9 };
|
|
|
33 static int *itable,*tables[3] = { grp_3tab , grp_5tab , grp_9tab };
|
|
|
34
|
|
|
35 for(i=0;i<3;i++)
|
|
|
36 {
|
|
|
37 itable = tables[i];
|
|
|
38 len = tablen[i];
|
|
|
39 for(j=0;j<len;j++)
|
|
|
40 for(k=0;k<len;k++)
|
|
|
41 for(l=0;l<len;l++)
|
|
|
42 {
|
|
|
43 *itable++ = base[i][l];
|
|
|
44 *itable++ = base[i][k];
|
|
|
45 *itable++ = base[i][j];
|
|
|
46 }
|
|
|
47 }
|
|
|
48
|
|
|
49 for(k=0;k<27;k++)
|
|
|
50 {
|
|
|
51 double m=mulmul[k];
|
|
|
52 table = muls[k];
|
|
|
53 for(j=3,i=0;i<63;i++,j--)
|
|
|
54 *table++ = m * pow(2.0,(double) j / 3.0);
|
|
|
55 *table++ = 0.0;
|
|
|
56 }
|
|
|
57 }
|
|
|
58
|
|
|
59
|
|
|
60 void II_step_one(unsigned int *bit_alloc,int *scale,struct frame *fr)
|
|
|
61 {
|
|
|
62 int stereo = fr->stereo-1;
|
|
|
63 int sblimit = fr->II_sblimit;
|
|
|
64 int jsbound = fr->jsbound;
|
|
|
65 int sblimit2 = fr->II_sblimit<<stereo;
|
|
|
66 struct al_table *alloc1 = fr->alloc;
|
|
|
67 int i;
|
|
|
68 static unsigned int scfsi_buf[64];
|
|
|
69 unsigned int *scfsi,*bita;
|
|
|
70 int sc,step;
|
|
|
71
|
|
|
72 bita = bit_alloc;
|
|
|
73 if(stereo)
|
|
|
74 {
|
|
|
75 for (i=jsbound;i;i--,alloc1+=(1<<step))
|
|
|
76 {
|
|
|
77 *bita++ = (char) getbits(step=alloc1->bits);
|
|
|
78 *bita++ = (char) getbits(step);
|
|
|
79 }
|
|
|
80 for (i=sblimit-jsbound;i;i--,alloc1+=(1<<step))
|
|
|
81 {
|
|
|
82 bita[0] = (char) getbits(step=alloc1->bits);
|
|
|
83 bita[1] = bita[0];
|
|
|
84 bita+=2;
|
|
|
85 }
|
|
|
86 bita = bit_alloc;
|
|
|
87 scfsi=scfsi_buf;
|
|
|
88 for (i=sblimit2;i;i--)
|
|
|
89 if (*bita++)
|
|
|
90 *scfsi++ = (char) getbits_fast(2);
|
|
|
91 }
|
|
|
92 else /* mono */
|
|
|
93 {
|
|
|
94 for (i=sblimit;i;i--,alloc1+=(1<<step))
|
|
|
95 *bita++ = (char) getbits(step=alloc1->bits);
|
|
|
96 bita = bit_alloc;
|
|
|
97 scfsi=scfsi_buf;
|
|
|
98 for (i=sblimit;i;i--)
|
|
|
99 if (*bita++)
|
|
|
100 *scfsi++ = (char) getbits_fast(2);
|
|
|
101 }
|
|
|
102
|
|
|
103 bita = bit_alloc;
|
|
|
104 scfsi=scfsi_buf;
|
|
|
105 for (i=sblimit2;i;i--)
|
|
|
106 if (*bita++)
|
|
|
107 switch (*scfsi++)
|
|
|
108 {
|
|
|
109 case 0:
|
|
|
110 *scale++ = getbits_fast(6);
|
|
|
111 *scale++ = getbits_fast(6);
|
|
|
112 *scale++ = getbits_fast(6);
|
|
|
113 break;
|
|
|
114 case 1 :
|
|
|
115 *scale++ = sc = getbits_fast(6);
|
|
|
116 *scale++ = sc;
|
|
|
117 *scale++ = getbits_fast(6);
|
|
|
118 break;
|
|
|
119 case 2:
|
|
|
120 *scale++ = sc = getbits_fast(6);
|
|
|
121 *scale++ = sc;
|
|
|
122 *scale++ = sc;
|
|
|
123 break;
|
|
|
124 default: /* case 3 */
|
|
|
125 *scale++ = getbits_fast(6);
|
|
|
126 *scale++ = sc = getbits_fast(6);
|
|
|
127 *scale++ = sc;
|
|
|
128 break;
|
|
|
129 }
|
|
|
130
|
|
|
131 }
|
|
|
132
|
|
|
133 void II_step_two(unsigned int *bit_alloc,real fraction[2][4][SBLIMIT],int *scale,struct frame *fr,int x1)
|
|
|
134 {
|
|
|
135 int i,j,k,ba;
|
|
|
136 int stereo = fr->stereo;
|
|
|
137 int sblimit = fr->II_sblimit;
|
|
|
138 int jsbound = fr->jsbound;
|
|
|
139 struct al_table *alloc2,*alloc1 = fr->alloc;
|
|
|
140 unsigned int *bita=bit_alloc;
|
|
|
141 int d1,step;
|
|
|
142
|
|
|
143 for (i=0;i<jsbound;i++,alloc1+=(1<<step))
|
|
|
144 {
|
|
|
145 step = alloc1->bits;
|
|
|
146 for (j=0;j<stereo;j++)
|
|
|
147 {
|
|
|
148 if ( (ba=*bita++) )
|
|
|
149 {
|
|
|
150 k=(alloc2 = alloc1+ba)->bits;
|
|
|
151 if( (d1=alloc2->d) < 0)
|
|
|
152 {
|
|
|
153 real cm=muls[k][scale[x1]];
|
|
|
154 fraction[j][0][i] = ((real) ((int)getbits(k) + d1)) * cm;
|
|
|
155 fraction[j][1][i] = ((real) ((int)getbits(k) + d1)) * cm;
|
|
|
156 fraction[j][2][i] = ((real) ((int)getbits(k) + d1)) * cm;
|
|
|
157 }
|
|
|
158 else
|
|
|
159 {
|
|
|
160 static int *table[] = { 0,0,0,grp_3tab,0,grp_5tab,0,0,0,grp_9tab };
|
|
|
161 unsigned int idx,*tab,m=scale[x1];
|
|
|
162 idx = (unsigned int) getbits(k);
|
|
|
163 tab = (unsigned int *) (table[d1] + idx + idx + idx);
|
|
|
164 fraction[j][0][i] = muls[*tab++][m];
|
|
|
165 fraction[j][1][i] = muls[*tab++][m];
|
|
|
166 fraction[j][2][i] = muls[*tab][m];
|
|
|
167 }
|
|
|
168 scale+=3;
|
|
|
169 }
|
|
|
170 else
|
|
|
171 fraction[j][0][i] = fraction[j][1][i] = fraction[j][2][i] = 0.0;
|
|
|
172 }
|
|
|
173 }
|
|
|
174
|
|
|
175 for (i=jsbound;i<sblimit;i++,alloc1+=(1<<step))
|
|
|
176 {
|
|
|
177 step = alloc1->bits;
|
|
|
178 bita++; /* channel 1 and channel 2 bitalloc are the same */
|
|
|
179 if ( (ba=*bita++) )
|
|
|
180 {
|
|
|
181 k=(alloc2 = alloc1+ba)->bits;
|
|
|
182 if( (d1=alloc2->d) < 0)
|
|
|
183 {
|
|
|
184 real cm;
|
|
|
185 cm=muls[k][scale[x1+3]];
|
|
|
186 fraction[1][0][i] = (fraction[0][0][i] = (real) ((int)getbits(k) + d1) ) * cm;
|
|
|
187 fraction[1][1][i] = (fraction[0][1][i] = (real) ((int)getbits(k) + d1) ) * cm;
|
|
|
188 fraction[1][2][i] = (fraction[0][2][i] = (real) ((int)getbits(k) + d1) ) * cm;
|
|
|
189 cm=muls[k][scale[x1]];
|
|
|
190 fraction[0][0][i] *= cm; fraction[0][1][i] *= cm; fraction[0][2][i] *= cm;
|
|
|
191 }
|
|
|
192 else
|
|
|
193 {
|
|
|
194 static int *table[] = { 0,0,0,grp_3tab,0,grp_5tab,0,0,0,grp_9tab };
|
|
|
195 unsigned int idx,*tab,m1,m2;
|
|
|
196 m1 = scale[x1]; m2 = scale[x1+3];
|
|
|
197 idx = (unsigned int) getbits(k);
|
|
|
198 tab = (unsigned int *) (table[d1] + idx + idx + idx);
|
|
|
199 fraction[0][0][i] = muls[*tab][m1]; fraction[1][0][i] = muls[*tab++][m2];
|
|
|
200 fraction[0][1][i] = muls[*tab][m1]; fraction[1][1][i] = muls[*tab++][m2];
|
|
|
201 fraction[0][2][i] = muls[*tab][m1]; fraction[1][2][i] = muls[*tab][m2];
|
|
|
202 }
|
|
|
203 scale+=6;
|
|
|
204 }
|
|
|
205 else {
|
|
|
206 fraction[0][0][i] = fraction[0][1][i] = fraction[0][2][i] =
|
|
|
207 fraction[1][0][i] = fraction[1][1][i] = fraction[1][2][i] = 0.0;
|
|
|
208 }
|
|
|
209 /*
|
|
|
210 should we use individual scalefac for channel 2 or
|
|
|
211 is the current way the right one , where we just copy channel 1 to
|
|
|
212 channel 2 ??
|
|
|
213 The current 'strange' thing is, that we throw away the scalefac
|
|
|
214 values for the second channel ...!!
|
|
|
215 -> changed .. now we use the scalefac values of channel one !!
|
|
|
216 */
|
|
|
217 }
|
|
|
218
|
|
|
219 for(i=sblimit;i<SBLIMIT;i++)
|
|
|
220 for (j=0;j<stereo;j++)
|
|
|
221 fraction[j][0][i] = fraction[j][1][i] = fraction[j][2][i] = 0.0;
|
|
|
222
|
|
|
223 }
|
|
|
224
|
|
|
225 static void II_select_table(struct frame *fr)
|
|
|
226 {
|
|
|
227 static int translate[3][2][16] =
|
|
|
228 { { { 0,2,2,2,2,2,2,0,0,0,1,1,1,1,1,0 } ,
|
|
|
229 { 0,2,2,0,0,0,1,1,1,1,1,1,1,1,1,0 } } ,
|
|
|
230 { { 0,2,2,2,2,2,2,0,0,0,0,0,0,0,0,0 } ,
|
|
|
231 { 0,2,2,0,0,0,0,0,0,0,0,0,0,0,0,0 } } ,
|
|
|
232 { { 0,3,3,3,3,3,3,0,0,0,1,1,1,1,1,0 } ,
|
|
|
233 { 0,3,3,0,0,0,1,1,1,1,1,1,1,1,1,0 } } };
|
|
|
234
|
|
|
235 int table,sblim;
|
|
|
236 static struct al_table *tables[5] =
|
|
|
237 { alloc_0, alloc_1, alloc_2, alloc_3 , alloc_4 };
|
|
|
238 static int sblims[5] = { 27 , 30 , 8, 12 , 30 };
|
|
|
239
|
|
|
240 if(fr->lsf)
|
|
|
241 table = 4;
|
|
|
242 else
|
|
|
243 table = translate[fr->sampling_frequency][2-fr->stereo][fr->bitrate_index];
|
|
|
244 sblim = sblims[table];
|
|
|
245
|
|
|
246 fr->alloc = tables[table];
|
|
|
247 fr->II_sblimit = sblim;
|
|
|
248 }
|
|
|
249
|
|
|
250 int do_layer2(struct frame *fr,unsigned char *pcm_sample,int *pcm_point)
|
|
|
251 {
|
|
|
252 int clip=0;
|
|
|
253 int i,j;
|
|
|
254 int stereo = fr->stereo;
|
|
|
255 real fraction[2][4][SBLIMIT]; /* pick_table clears unused subbands */
|
|
|
256 unsigned int bit_alloc[64];
|
|
|
257 int scale[192];
|
|
|
258 int single = fr->single;
|
|
|
259
|
|
|
260 II_select_table(fr);
|
|
|
261 fr->jsbound = (fr->mode == MPG_MD_JOINT_STEREO) ?
|
|
|
262 (fr->mode_ext<<2)+4 : fr->II_sblimit;
|
|
|
263
|
|
|
264 if(stereo == 1 || single == 3)
|
|
|
265 single = 0;
|
|
|
266
|
|
|
267 II_step_one(bit_alloc, scale, fr);
|
|
|
268
|
|
|
269 for (i=0;i<SCALE_BLOCK;i++)
|
|
|
270 {
|
|
|
271 II_step_two(bit_alloc,fraction,scale,fr,i>>2);
|
|
|
272 for (j=0;j<3;j++) {
|
|
|
273 if(single >= 0) {
|
|
|
274 clip += synth_1to1_mono(fraction[0][j],pcm_sample,pcm_point);
|
|
|
275 }
|
|
|
276 else {
|
|
|
277 int p1 = *pcm_point;
|
|
|
278 clip += synth_1to1(fraction[0][j],0,pcm_sample,&p1);
|
|
|
279 clip += synth_1to1(fraction[1][j],1,pcm_sample,pcm_point);
|
|
|
280 }
|
|
|
281
|
|
|
282 }
|
|
|
283 }
|
|
|
284
|
|
|
285 return clip;
|
|
|
286 }
|
|
|
287
|
|
|
288
|
