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1
/*
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 * MPEG Audio decoder
3
 * Copyright (c) 2001 Gerard Lantau.
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 *
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 * This program is free software; you can redistribute it and/or modify
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 * it under the terms of the GNU General Public License as published by
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 * the Free Software Foundation; either version 2 of the License, or
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 * (at your option) any later version.
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 *
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 * This program is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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 * GNU General Public License for more details.
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 *
15
 * You should have received a copy of the GNU General Public License
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 * along with this program; if not, write to the Free Software
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 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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 */
19
//#define DEBUG
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#include "avcodec.h"
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#include <math.h>
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#include "mpegaudio.h"
23

    
24
/*
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 * TODO:
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 *  - in low precision mode, use more 16 bit multiplies in synth filter
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 *  - test lsf / mpeg25 extensively.
28
 */
29

    
30
/* define USE_HIGHPRECISION to have a bit exact (but slower) mpeg
31
   audio decoder */
32
//#define USE_HIGHPRECISION
33

    
34
#ifdef USE_HIGHPRECISION
35
#define FRAC_BITS   23   /* fractional bits for sb_samples and dct */
36
#define WFRAC_BITS  16   /* fractional bits for window */
37
#else
38
#define FRAC_BITS   15   /* fractional bits for sb_samples and dct */
39
#define WFRAC_BITS  14   /* fractional bits for window */
40
#endif
41

    
42
#define FRAC_ONE    (1 << FRAC_BITS)
43

    
44
#define MULL(a,b) (((INT64)(a) * (INT64)(b)) >> FRAC_BITS)
45
#define MUL64(a,b) ((INT64)(a) * (INT64)(b))
46
#define FIX(a)   ((int)((a) * FRAC_ONE))
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/* WARNING: only correct for posititive numbers */
48
#define FIXR(a)   ((int)((a) * FRAC_ONE + 0.5))
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#define FRAC_RND(a) (((a) + (FRAC_ONE/2)) >> FRAC_BITS)
50

    
51
#if FRAC_BITS <= 15
52
typedef INT16 MPA_INT;
53
#else
54
typedef INT32 MPA_INT;
55
#endif
56

    
57
/****************/
58

    
59
#define HEADER_SIZE 4
60
#define BACKSTEP_SIZE 512
61

    
62
typedef struct MPADecodeContext {
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    UINT8 inbuf1[2][MPA_MAX_CODED_FRAME_SIZE + BACKSTEP_SIZE];        /* input buffer */
64
    int inbuf_index;
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    UINT8 *inbuf_ptr, *inbuf;
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    int frame_size;
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    int free_format_frame_size; /* frame size in case of free format
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                                   (zero if currently unknown) */
69
    /* next header (used in free format parsing) */
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    UINT32 free_format_next_header; 
71
    int error_protection;
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    int layer;
73
    int sample_rate;
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    int sample_rate_index; /* between 0 and 8 */
75
    int bit_rate;
76
    int old_frame_size;
77
    GetBitContext gb;
78
    int nb_channels;
79
    int mode;
80
    int mode_ext;
81
    int lsf;
82
    MPA_INT synth_buf[MPA_MAX_CHANNELS][512 * 2];
83
    int synth_buf_offset[MPA_MAX_CHANNELS];
84
    INT32 sb_samples[MPA_MAX_CHANNELS][36][SBLIMIT];
85
    INT32 mdct_buf[MPA_MAX_CHANNELS][SBLIMIT * 18]; /* previous samples, for layer 3 MDCT */
86
#ifdef DEBUG
87
    int frame_count;
88
#endif
89
} MPADecodeContext;
90

    
91
/* layer 3 "granule" */
92
typedef struct GranuleDef {
93
    UINT8 scfsi;
94
    int part2_3_length;
95
    int big_values;
96
    int global_gain;
97
    int scalefac_compress;
98
    UINT8 block_type;
99
    UINT8 switch_point;
100
    int table_select[3];
101
    int subblock_gain[3];
102
    UINT8 scalefac_scale;
103
    UINT8 count1table_select;
104
    int region_size[3]; /* number of huffman codes in each region */
105
    int preflag;
106
    int short_start, long_end; /* long/short band indexes */
107
    UINT8 scale_factors[40];
108
    INT32 sb_hybrid[SBLIMIT * 18]; /* 576 samples */
109
} GranuleDef;
110

    
111
#define MODE_EXT_MS_STEREO 2
112
#define MODE_EXT_I_STEREO  1
113

    
114
/* layer 3 huffman tables */
115
typedef struct HuffTable {
116
    int xsize;
117
    const UINT8 *bits;
118
    const UINT16 *codes;
119
} HuffTable;
120

    
121
#include "mpegaudiodectab.h"
122

    
123
/* vlc structure for decoding layer 3 huffman tables */
124
static VLC huff_vlc[16]; 
125
static UINT8 *huff_code_table[16];
126
static VLC huff_quad_vlc[2];
127
/* computed from band_size_long */
128
static UINT16 band_index_long[9][23];
129
/* XXX: free when all decoders are closed */
130
#define TABLE_4_3_SIZE (8191 + 16)
131
static UINT8  *table_4_3_exp;
132
#if FRAC_BITS <= 15
133
static UINT16 *table_4_3_value;
134
#else
135
static UINT32 *table_4_3_value;
136
#endif
137
/* intensity stereo coef table */
138
static INT32 is_table[2][16];
139
static INT32 is_table_lsf[2][2][16];
140
static INT32 csa_table[8][2];
141
static INT32 mdct_win[8][36];
142

    
143
/* lower 2 bits: modulo 3, higher bits: shift */
144
static UINT16 scale_factor_modshift[64];
145
/* [i][j]:  2^(-j/3) * FRAC_ONE * 2^(i+2) / (2^(i+2) - 1) */
146
static INT32 scale_factor_mult[15][3];
147
/* mult table for layer 2 group quantization */
148

    
149
#define SCALE_GEN(v) \
150
{ FIXR(1.0 * (v)), FIXR(0.7937005259 * (v)), FIXR(0.6299605249 * (v)) }
151

    
152
static INT32 scale_factor_mult2[3][3] = {
153
    SCALE_GEN(1.0 / 3.0), /* 3 steps */
154
    SCALE_GEN(1.0 / 5.0), /* 5 steps */
155
    SCALE_GEN(1.0 / 9.0), /* 9 steps */
156
};
157

    
158
/* 2^(n/4) */
159
static UINT32 scale_factor_mult3[4] = {
160
    FIXR(1.0),
161
    FIXR(1.18920711500272106671),
162
    FIXR(1.41421356237309504880),
163
    FIXR(1.68179283050742908605),
164
};
165

    
166
static MPA_INT window[512];
167
    
168
/* layer 1 unscaling */
169
/* n = number of bits of the mantissa minus 1 */
170
static inline int l1_unscale(int n, int mant, int scale_factor)
171
{
172
    int shift, mod;
173
    INT64 val;
174

    
175
    shift = scale_factor_modshift[scale_factor];
176
    mod = shift & 3;
177
    shift >>= 2;
178
    val = MUL64(mant + (-1 << n) + 1, scale_factor_mult[n-1][mod]);
179
    shift += n;
180
    return (int)((val + (1 << (shift - 1))) >> shift);
181
}
182

    
183
static inline int l2_unscale_group(int steps, int mant, int scale_factor)
184
{
185
    int shift, mod, val;
186

    
187
    shift = scale_factor_modshift[scale_factor];
188
    mod = shift & 3;
189
    shift >>= 2;
190
    /* XXX: store the result directly */
191
    val = (2 * (mant - (steps >> 1))) * scale_factor_mult2[steps >> 2][mod];
192
    return (val + (1 << (shift - 1))) >> shift;
193
}
194

    
195
/* compute value^(4/3) * 2^(exponent/4). It normalized to FRAC_BITS */
196
static inline int l3_unscale(int value, int exponent)
197
{
198
#if FRAC_BITS <= 15    
199
    unsigned int m;
200
#else
201
    UINT64 m;
202
#endif
203
    int e;
204

    
205
    e = table_4_3_exp[value];
206
    e += (exponent >> 2);
207
    e = FRAC_BITS - e;
208
#if FRAC_BITS <= 15    
209
    if (e > 31)
210
        e = 31;
211
#endif
212
    m = table_4_3_value[value];
213
#if FRAC_BITS <= 15    
214
    m = (m * scale_factor_mult3[exponent & 3]);
215
    m = (m + (1 << (e-1))) >> e;
216
    return m;
217
#else
218
    m = MUL64(m, scale_factor_mult3[exponent & 3]);
219
    m = (m + (UINT64_C(1) << (e-1))) >> e;
220
    return m;
221
#endif
222
}
223

    
224

    
225
static int decode_init(AVCodecContext * avctx)
226
{
227
    MPADecodeContext *s = avctx->priv_data;
228
    static int init;
229
    int i, j, k;
230

    
231
    if(!init) {
232
        /* scale factors table for layer 1/2 */
233
        for(i=0;i<64;i++) {
234
            int shift, mod;
235
            /* 1.0 (i = 3) is normalized to 2 ^ FRAC_BITS */
236
            shift = (i / 3) - 1;
237
            mod = i % 3;
238
#if FRAC_BITS <= 15
239
            if (shift > 31)
240
                shift = 31;
241
#endif
242
            scale_factor_modshift[i] = mod | (shift << 2);
243
        }
244

    
245
        /* scale factor multiply for layer 1 */
246
        for(i=0;i<15;i++) {
247
            int n, norm;
248
            n = i + 2;
249
            norm = ((INT64_C(1) << n) * FRAC_ONE) / ((1 << n) - 1);
250
            scale_factor_mult[i][0] = MULL(FIXR(1.0), norm);
251
            scale_factor_mult[i][1] = MULL(FIXR(0.7937005259), norm);
252
            scale_factor_mult[i][2] = MULL(FIXR(0.6299605249), norm);
253
            dprintf("%d: norm=%x s=%x %x %x\n",
254
                    i, norm, 
255
                    scale_factor_mult[i][0],
256
                    scale_factor_mult[i][1],
257
                    scale_factor_mult[i][2]);
258
        }
259
        
260
        /* window */
261
        /* max = 18760, max sum over all 16 coefs : 44736 */
262
        for(i=0;i<257;i++) {
263
            int v;
264
            v = mpa_enwindow[i];
265
#if WFRAC_BITS < 16
266
            v = (v + (1 << (16 - WFRAC_BITS - 1))) >> (16 - WFRAC_BITS);
267
#endif
268
            window[i] = v;
269
            if ((i & 63) != 0)
270
                v = -v;
271
            if (i != 0)
272
                window[512 - i] = v;
273
        }
274
        
275
        /* huffman decode tables */
276
        huff_code_table[0] = NULL;
277
        for(i=1;i<16;i++) {
278
            const HuffTable *h = &mpa_huff_tables[i];
279
            int xsize, n, x, y;
280
            UINT8 *code_table;
281

    
282
            xsize = h->xsize;
283
            n = xsize * xsize;
284
            /* XXX: fail test */
285
            init_vlc(&huff_vlc[i], 8, n, 
286
                     h->bits, 1, 1, h->codes, 2, 2);
287
            
288
            code_table = av_mallocz(n);
289
            j = 0;
290
            for(x=0;x<xsize;x++) {
291
                for(y=0;y<xsize;y++)
292
                    code_table[j++] = (x << 4) | y;
293
            }
294
            huff_code_table[i] = code_table;
295
        }
296
        for(i=0;i<2;i++) {
297
            init_vlc(&huff_quad_vlc[i], i == 0 ? 7 : 4, 16, 
298
                     mpa_quad_bits[i], 1, 1, mpa_quad_codes[i], 1, 1);
299
        }
300

    
301
        for(i=0;i<9;i++) {
302
            k = 0;
303
            for(j=0;j<22;j++) {
304
                band_index_long[i][j] = k;
305
                k += band_size_long[i][j];
306
            }
307
            band_index_long[i][22] = k;
308
        }
309

    
310
        /* compute n ^ (4/3) and store it in mantissa/exp format */
311
        table_4_3_exp = av_mallocz(TABLE_4_3_SIZE * 
312
                                   sizeof(table_4_3_exp[0]));
313
        if (!table_4_3_exp)
314
            return -1;
315
        table_4_3_value = av_mallocz(TABLE_4_3_SIZE * 
316
                                     sizeof(table_4_3_value[0]));
317
        if (!table_4_3_value) {
318
            free(table_4_3_exp);
319
            return -1;
320
        }
321
        
322
        for(i=1;i<TABLE_4_3_SIZE;i++) {
323
            double f, fm;
324
            int e, m;
325
            f = pow((double)i, 4.0 / 3.0);
326
            fm = frexp(f, &e);
327
            m = FIXR(2 * fm);
328
#if FRAC_BITS <= 15
329
            if ((unsigned short)m != m)
330
                m = 65535;
331
#endif
332
            /* normalized to FRAC_BITS */
333
            table_4_3_value[i] = m;
334
            table_4_3_exp[i] = e - 1;
335
        }
336

    
337
        
338
        for(i=0;i<7;i++) {
339
            float f;
340
            int v;
341
            if (i != 6) {
342
                f = tan((double)i * M_PI / 12.0);
343
                v = FIXR(f / (1.0 + f));
344
            } else {
345
                v = FIXR(1.0);
346
            }
347
            is_table[0][i] = v;
348
            is_table[1][6 - i] = v;
349
        }
350
        /* invalid values */
351
        for(i=7;i<16;i++)
352
            is_table[0][i] = is_table[1][i] = 0.0;
353

    
354
        for(i=0;i<16;i++) {
355
            double f;
356
            int e, k;
357

    
358
            for(j=0;j<2;j++) {
359
                e = -(j + 1) * ((i + 1) >> 1);
360
                f = pow(2.0, e / 4.0);
361
                k = i & 1;
362
                is_table_lsf[j][k ^ 1][i] = FIXR(f);
363
                is_table_lsf[j][k][i] = FIXR(1.0);
364
                dprintf("is_table_lsf %d %d: %x %x\n", 
365
                        i, j, is_table_lsf[j][0][i], is_table_lsf[j][1][i]);
366
            }
367
        }
368

    
369
        for(i=0;i<8;i++) {
370
            float ci, cs, ca;
371
            ci = ci_table[i];
372
            cs = 1.0 / sqrt(1.0 + ci * ci);
373
            ca = cs * ci;
374
            csa_table[i][0] = FIX(cs);
375
            csa_table[i][1] = FIX(ca);
376
        }
377

    
378
        /* compute mdct windows */
379
        for(i=0;i<36;i++) {
380
            int v;
381
            v = FIXR(sin(M_PI * (i + 0.5) / 36.0));
382
            mdct_win[0][i] = v;
383
            mdct_win[1][i] = v;
384
            mdct_win[3][i] = v;
385
        }
386
        for(i=0;i<6;i++) {
387
            mdct_win[1][18 + i] = FIXR(1.0);
388
            mdct_win[1][24 + i] = FIXR(sin(M_PI * ((i + 6) + 0.5) / 12.0));
389
            mdct_win[1][30 + i] = FIXR(0.0);
390

    
391
            mdct_win[3][i] = FIXR(0.0);
392
            mdct_win[3][6 + i] = FIXR(sin(M_PI * (i + 0.5) / 12.0));
393
            mdct_win[3][12 + i] = FIXR(1.0);
394
        }
395

    
396
        for(i=0;i<12;i++)
397
            mdct_win[2][i] = FIXR(sin(M_PI * (i + 0.5) / 12.0));
398
        
399
        /* NOTE: we do frequency inversion adter the MDCT by changing
400
           the sign of the right window coefs */
401
        for(j=0;j<4;j++) {
402
            for(i=0;i<36;i+=2) {
403
                mdct_win[j + 4][i] = mdct_win[j][i];
404
                mdct_win[j + 4][i + 1] = -mdct_win[j][i + 1];
405
            }
406
        }
407

    
408
#if defined(DEBUG)
409
        for(j=0;j<8;j++) {
410
            printf("win%d=\n", j);
411
            for(i=0;i<36;i++)
412
                printf("%f, ", (double)mdct_win[j][i] / FRAC_ONE);
413
            printf("\n");
414
        }
415
#endif
416
        init = 1;
417
    }
418

    
419
    s->inbuf_index = 0;
420
    s->inbuf = &s->inbuf1[s->inbuf_index][BACKSTEP_SIZE];
421
    s->inbuf_ptr = s->inbuf;
422
#ifdef DEBUG
423
    s->frame_count = 0;
424
#endif
425
    return 0;
426
}
427

    
428
/* tab[i][j] = 1.0 / (2.0 * cos(pi*(2*k+1) / 2^(6 - j))) */;
429

    
430
/* cos(i*pi/64) */
431

    
432
#define COS0_0  FIXR(0.50060299823519630134)
433
#define COS0_1  FIXR(0.50547095989754365998)
434
#define COS0_2  FIXR(0.51544730992262454697)
435
#define COS0_3  FIXR(0.53104259108978417447)
436
#define COS0_4  FIXR(0.55310389603444452782)
437
#define COS0_5  FIXR(0.58293496820613387367)
438
#define COS0_6  FIXR(0.62250412303566481615)
439
#define COS0_7  FIXR(0.67480834145500574602)
440
#define COS0_8  FIXR(0.74453627100229844977)
441
#define COS0_9  FIXR(0.83934964541552703873)
442
#define COS0_10 FIXR(0.97256823786196069369)
443
#define COS0_11 FIXR(1.16943993343288495515)
444
#define COS0_12 FIXR(1.48416461631416627724)
445
#define COS0_13 FIXR(2.05778100995341155085)
446
#define COS0_14 FIXR(3.40760841846871878570)
447
#define COS0_15 FIXR(10.19000812354805681150)
448

    
449
#define COS1_0 FIXR(0.50241928618815570551)
450
#define COS1_1 FIXR(0.52249861493968888062)
451
#define COS1_2 FIXR(0.56694403481635770368)
452
#define COS1_3 FIXR(0.64682178335999012954)
453
#define COS1_4 FIXR(0.78815462345125022473)
454
#define COS1_5 FIXR(1.06067768599034747134)
455
#define COS1_6 FIXR(1.72244709823833392782)
456
#define COS1_7 FIXR(5.10114861868916385802)
457

    
458
#define COS2_0 FIXR(0.50979557910415916894)
459
#define COS2_1 FIXR(0.60134488693504528054)
460
#define COS2_2 FIXR(0.89997622313641570463)
461
#define COS2_3 FIXR(2.56291544774150617881)
462

    
463
#define COS3_0 FIXR(0.54119610014619698439)
464
#define COS3_1 FIXR(1.30656296487637652785)
465

    
466
#define COS4_0 FIXR(0.70710678118654752439)
467

    
468
/* butterfly operator */
469
#define BF(a, b, c)\
470
{\
471
    tmp0 = tab[a] + tab[b];\
472
    tmp1 = tab[a] - tab[b];\
473
    tab[a] = tmp0;\
474
    tab[b] = MULL(tmp1, c);\
475
}
476

    
477
#define BF1(a, b, c, d)\
478
{\
479
    BF(a, b, COS4_0);\
480
    BF(c, d, -COS4_0);\
481
    tab[c] += tab[d];\
482
}
483

    
484
#define BF2(a, b, c, d)\
485
{\
486
    BF(a, b, COS4_0);\
487
    BF(c, d, -COS4_0);\
488
    tab[c] += tab[d];\
489
    tab[a] += tab[c];\
490
    tab[c] += tab[b];\
491
    tab[b] += tab[d];\
492
}
493

    
494
#define ADD(a, b) tab[a] += tab[b]
495

    
496
/* DCT32 without 1/sqrt(2) coef zero scaling. */
497
static void dct32(INT32 *out, INT32 *tab)
498
{
499
    int tmp0, tmp1;
500

    
501
    /* pass 1 */
502
    BF(0, 31, COS0_0);
503
    BF(1, 30, COS0_1);
504
    BF(2, 29, COS0_2);
505
    BF(3, 28, COS0_3);
506
    BF(4, 27, COS0_4);
507
    BF(5, 26, COS0_5);
508
    BF(6, 25, COS0_6);
509
    BF(7, 24, COS0_7);
510
    BF(8, 23, COS0_8);
511
    BF(9, 22, COS0_9);
512
    BF(10, 21, COS0_10);
513
    BF(11, 20, COS0_11);
514
    BF(12, 19, COS0_12);
515
    BF(13, 18, COS0_13);
516
    BF(14, 17, COS0_14);
517
    BF(15, 16, COS0_15);
518

    
519
    /* pass 2 */
520
    BF(0, 15, COS1_0);
521
    BF(1, 14, COS1_1);
522
    BF(2, 13, COS1_2);
523
    BF(3, 12, COS1_3);
524
    BF(4, 11, COS1_4);
525
    BF(5, 10, COS1_5);
526
    BF(6,  9, COS1_6);
527
    BF(7,  8, COS1_7);
528
    
529
    BF(16, 31, -COS1_0);
530
    BF(17, 30, -COS1_1);
531
    BF(18, 29, -COS1_2);
532
    BF(19, 28, -COS1_3);
533
    BF(20, 27, -COS1_4);
534
    BF(21, 26, -COS1_5);
535
    BF(22, 25, -COS1_6);
536
    BF(23, 24, -COS1_7);
537
    
538
    /* pass 3 */
539
    BF(0, 7, COS2_0);
540
    BF(1, 6, COS2_1);
541
    BF(2, 5, COS2_2);
542
    BF(3, 4, COS2_3);
543
    
544
    BF(8, 15, -COS2_0);
545
    BF(9, 14, -COS2_1);
546
    BF(10, 13, -COS2_2);
547
    BF(11, 12, -COS2_3);
548
    
549
    BF(16, 23, COS2_0);
550
    BF(17, 22, COS2_1);
551
    BF(18, 21, COS2_2);
552
    BF(19, 20, COS2_3);
553
    
554
    BF(24, 31, -COS2_0);
555
    BF(25, 30, -COS2_1);
556
    BF(26, 29, -COS2_2);
557
    BF(27, 28, -COS2_3);
558

    
559
    /* pass 4 */
560
    BF(0, 3, COS3_0);
561
    BF(1, 2, COS3_1);
562
    
563
    BF(4, 7, -COS3_0);
564
    BF(5, 6, -COS3_1);
565
    
566
    BF(8, 11, COS3_0);
567
    BF(9, 10, COS3_1);
568
    
569
    BF(12, 15, -COS3_0);
570
    BF(13, 14, -COS3_1);
571
    
572
    BF(16, 19, COS3_0);
573
    BF(17, 18, COS3_1);
574
    
575
    BF(20, 23, -COS3_0);
576
    BF(21, 22, -COS3_1);
577
    
578
    BF(24, 27, COS3_0);
579
    BF(25, 26, COS3_1);
580
    
581
    BF(28, 31, -COS3_0);
582
    BF(29, 30, -COS3_1);
583
    
584
    /* pass 5 */
585
    BF1(0, 1, 2, 3);
586
    BF2(4, 5, 6, 7);
587
    BF1(8, 9, 10, 11);
588
    BF2(12, 13, 14, 15);
589
    BF1(16, 17, 18, 19);
590
    BF2(20, 21, 22, 23);
591
    BF1(24, 25, 26, 27);
592
    BF2(28, 29, 30, 31);
593
    
594
    /* pass 6 */
595
    
596
    ADD( 8, 12);
597
    ADD(12, 10);
598
    ADD(10, 14);
599
    ADD(14,  9);
600
    ADD( 9, 13);
601
    ADD(13, 11);
602
    ADD(11, 15);
603

    
604
    out[ 0] = tab[0];
605
    out[16] = tab[1];
606
    out[ 8] = tab[2];
607
    out[24] = tab[3];
608
    out[ 4] = tab[4];
609
    out[20] = tab[5];
610
    out[12] = tab[6];
611
    out[28] = tab[7];
612
    out[ 2] = tab[8];
613
    out[18] = tab[9];
614
    out[10] = tab[10];
615
    out[26] = tab[11];
616
    out[ 6] = tab[12];
617
    out[22] = tab[13];
618
    out[14] = tab[14];
619
    out[30] = tab[15];
620
    
621
    ADD(24, 28);
622
    ADD(28, 26);
623
    ADD(26, 30);
624
    ADD(30, 25);
625
    ADD(25, 29);
626
    ADD(29, 27);
627
    ADD(27, 31);
628

    
629
    out[ 1] = tab[16] + tab[24];
630
    out[17] = tab[17] + tab[25];
631
    out[ 9] = tab[18] + tab[26];
632
    out[25] = tab[19] + tab[27];
633
    out[ 5] = tab[20] + tab[28];
634
    out[21] = tab[21] + tab[29];
635
    out[13] = tab[22] + tab[30];
636
    out[29] = tab[23] + tab[31];
637
    out[ 3] = tab[24] + tab[20];
638
    out[19] = tab[25] + tab[21];
639
    out[11] = tab[26] + tab[22];
640
    out[27] = tab[27] + tab[23];
641
    out[ 7] = tab[28] + tab[18];
642
    out[23] = tab[29] + tab[19];
643
    out[15] = tab[30] + tab[17];
644
    out[31] = tab[31];
645
}
646

    
647
#define OUT_SHIFT (WFRAC_BITS + FRAC_BITS - 15)
648

    
649
#if FRAC_BITS <= 15
650

    
651
#define OUT_SAMPLE(sum)\
652
{\
653
    int sum1;\
654
    sum1 = (sum + (1 << (OUT_SHIFT - 1))) >> OUT_SHIFT;\
655
    if (sum1 < -32768)\
656
        sum1 = -32768;\
657
    else if (sum1 > 32767)\
658
        sum1 = 32767;\
659
    *samples = sum1;\
660
    samples += incr;\
661
}
662

    
663
#define SUM8(off, op)                           \
664
{                                               \
665
    sum op w[0 * 64 + off] * p[0 * 64];\
666
    sum op w[1 * 64 + off] * p[1 * 64];\
667
    sum op w[2 * 64 + off] * p[2 * 64];\
668
    sum op w[3 * 64 + off] * p[3 * 64];\
669
    sum op w[4 * 64 + off] * p[4 * 64];\
670
    sum op w[5 * 64 + off] * p[5 * 64];\
671
    sum op w[6 * 64 + off] * p[6 * 64];\
672
    sum op w[7 * 64 + off] * p[7 * 64];\
673
}
674

    
675
#else
676

    
677
#define OUT_SAMPLE(sum)\
678
{\
679
    int sum1;\
680
    sum1 = (int)((sum + (INT64_C(1) << (OUT_SHIFT - 1))) >> OUT_SHIFT);\
681
    if (sum1 < -32768)\
682
        sum1 = -32768;\
683
    else if (sum1 > 32767)\
684
        sum1 = 32767;\
685
    *samples = sum1;\
686
    samples += incr;\
687
}
688

    
689
#define SUM8(off, op)                           \
690
{                                               \
691
    sum op MUL64(w[0 * 64 + off], p[0 * 64]);\
692
    sum op MUL64(w[1 * 64 + off], p[1 * 64]);\
693
    sum op MUL64(w[2 * 64 + off], p[2 * 64]);\
694
    sum op MUL64(w[3 * 64 + off], p[3 * 64]);\
695
    sum op MUL64(w[4 * 64 + off], p[4 * 64]);\
696
    sum op MUL64(w[5 * 64 + off], p[5 * 64]);\
697
    sum op MUL64(w[6 * 64 + off], p[6 * 64]);\
698
    sum op MUL64(w[7 * 64 + off], p[7 * 64]);\
699
}
700

    
701
#endif
702

    
703
/* 32 sub band synthesis filter. Input: 32 sub band samples, Output:
704
   32 samples. */
705
/* XXX: optimize by avoiding ring buffer usage */
706
static void synth_filter(MPADecodeContext *s1,
707
                         int ch, INT16 *samples, int incr, 
708
                         INT32 sb_samples[SBLIMIT])
709
{
710
    INT32 tmp[32];
711
    register MPA_INT *synth_buf, *p;
712
    register MPA_INT *w;
713
    int j, offset, v;
714
#if FRAC_BITS <= 15
715
    int sum;
716
#else
717
    INT64 sum;
718
#endif
719

    
720
    dct32(tmp, sb_samples);
721
    
722
    offset = s1->synth_buf_offset[ch];
723
    synth_buf = s1->synth_buf[ch] + offset;
724

    
725
    for(j=0;j<32;j++) {
726
        v = tmp[j];
727
#if FRAC_BITS <= 15
728
        if (v > 32767)
729
            v = 32767;
730
        else if (v < -32768)
731
            v = -32768;
732
#endif
733
        synth_buf[j] = v;
734
    }
735
    /* copy to avoid wrap */
736
    memcpy(synth_buf + 512, synth_buf, 32 * sizeof(MPA_INT));
737

    
738
    w = window;
739
    for(j=0;j<16;j++) {
740
        sum = 0;
741
        p = synth_buf + 16 + j;    /* 0-15  */
742
        SUM8(0, +=);
743
        p = synth_buf + 48 - j;    /* 32-47 */
744
        SUM8(32, -=);
745
        OUT_SAMPLE(sum);
746
        w++;
747
    }
748
    
749
    p = synth_buf + 32; /* 48 */
750
    sum = 0;
751
    SUM8(32, -=);
752
    OUT_SAMPLE(sum);
753
    w++;
754

    
755
    for(j=17;j<32;j++) {
756
        sum = 0;
757
        p = synth_buf + 48 - j; /* 17-31 */
758
        SUM8(0, -=);
759
        p = synth_buf + 16 + j; /* 49-63 */
760
        SUM8(32, -=);
761
        OUT_SAMPLE(sum);
762
        w++;
763
    }
764
    offset = (offset - 32) & 511;
765
    s1->synth_buf_offset[ch] = offset;
766
}
767

    
768
/* cos(pi*i/24) */
769
#define C1  FIXR(0.99144486137381041114)
770
#define C3  FIXR(0.92387953251128675612)
771
#define C5  FIXR(0.79335334029123516458)
772
#define C7  FIXR(0.60876142900872063941)
773
#define C9  FIXR(0.38268343236508977173)
774
#define C11 FIXR(0.13052619222005159154)
775

    
776
/* 12 points IMDCT. We compute it "by hand" by factorizing obvious
777
   cases. */
778
static void imdct12(int *out, int *in)
779
{
780
    int tmp;
781
    INT64 in1_3, in1_9, in4_3, in4_9;
782

    
783
    in1_3 = MUL64(in[1], C3);
784
    in1_9 = MUL64(in[1], C9);
785
    in4_3 = MUL64(in[4], C3);
786
    in4_9 = MUL64(in[4], C9);
787
    
788
    tmp = FRAC_RND(MUL64(in[0], C7) - in1_3 - MUL64(in[2], C11) + 
789
                   MUL64(in[3], C1) - in4_9 - MUL64(in[5], C5));
790
    out[0] = tmp;
791
    out[5] = -tmp;
792
    tmp = FRAC_RND(MUL64(in[0] - in[3], C9) - in1_3 + 
793
                   MUL64(in[2] + in[5], C3) - in4_9);
794
    out[1] = tmp;
795
    out[4] = -tmp;
796
    tmp = FRAC_RND(MUL64(in[0], C11) - in1_9 + MUL64(in[2], C7) -
797
                   MUL64(in[3], C5) + in4_3 - MUL64(in[5], C1));
798
    out[2] = tmp;
799
    out[3] = -tmp;
800
    tmp = FRAC_RND(MUL64(-in[0], C5) + in1_9 + MUL64(in[2], C1) + 
801
                   MUL64(in[3], C11) - in4_3 - MUL64(in[5], C7));
802
    out[6] = tmp;
803
    out[11] = tmp;
804
    tmp = FRAC_RND(MUL64(-in[0] + in[3], C3) - in1_9 + 
805
                   MUL64(in[2] + in[5], C9) + in4_3);
806
    out[7] = tmp;
807
    out[10] = tmp;
808
    tmp = FRAC_RND(-MUL64(in[0], C1) - in1_3 - MUL64(in[2], C5) -
809
                   MUL64(in[3], C7) - in4_9 - MUL64(in[5], C11));
810
    out[8] = tmp;
811
    out[9] = tmp;
812
}
813

    
814
#undef C1
815
#undef C3
816
#undef C5
817
#undef C7
818
#undef C9
819
#undef C11
820

    
821
/* cos(pi*i/18) */
822
#define C1 FIXR(0.98480775301220805936)
823
#define C2 FIXR(0.93969262078590838405)
824
#define C3 FIXR(0.86602540378443864676)
825
#define C4 FIXR(0.76604444311897803520)
826
#define C5 FIXR(0.64278760968653932632)
827
#define C6 FIXR(0.5)
828
#define C7 FIXR(0.34202014332566873304)
829
#define C8 FIXR(0.17364817766693034885)
830

    
831
/* 0.5 / cos(pi*(2*i+1)/36) */
832
static const int icos36[9] = {
833
    FIXR(0.50190991877167369479),
834
    FIXR(0.51763809020504152469),
835
    FIXR(0.55168895948124587824),
836
    FIXR(0.61038729438072803416),
837
    FIXR(0.70710678118654752439),
838
    FIXR(0.87172339781054900991),
839
    FIXR(1.18310079157624925896),
840
    FIXR(1.93185165257813657349),
841
    FIXR(5.73685662283492756461),
842
};
843

    
844
static const int icos72[18] = {
845
    /* 0.5 / cos(pi*(2*i+19)/72) */
846
    FIXR(0.74009361646113053152),
847
    FIXR(0.82133981585229078570),
848
    FIXR(0.93057949835178895673),
849
    FIXR(1.08284028510010010928),
850
    FIXR(1.30656296487637652785),
851
    FIXR(1.66275476171152078719),
852
    FIXR(2.31011315767264929558),
853
    FIXR(3.83064878777019433457),
854
    FIXR(11.46279281302667383546),
855

    
856
    /* 0.5 / cos(pi*(2*(i + 18) +19)/72) */
857
    FIXR(-0.67817085245462840086),
858
    FIXR(-0.63023620700513223342),
859
    FIXR(-0.59284452371708034528),
860
    FIXR(-0.56369097343317117734),
861
    FIXR(-0.54119610014619698439),
862
    FIXR(-0.52426456257040533932),
863
    FIXR(-0.51213975715725461845),
864
    FIXR(-0.50431448029007636036),
865
    FIXR(-0.50047634258165998492),
866
};
867

    
868
/* using Lee like decomposition followed by hand coded 9 points DCT */
869
static void imdct36(int *out, int *in)
870
{
871
    int i, j, t0, t1, t2, t3, s0, s1, s2, s3;
872
    int tmp[18], *tmp1, *in1;
873
    INT64 in3_3, in6_6;
874

    
875
    for(i=17;i>=1;i--)
876
        in[i] += in[i-1];
877
    for(i=17;i>=3;i-=2)
878
        in[i] += in[i-2];
879

    
880
    for(j=0;j<2;j++) {
881
        tmp1 = tmp + j;
882
        in1 = in + j;
883

    
884
        in3_3 = MUL64(in1[2*3], C3);
885
        in6_6 = MUL64(in1[2*6], C6);
886

    
887
        tmp1[0] = FRAC_RND(MUL64(in1[2*1], C1) + in3_3 + 
888
                           MUL64(in1[2*5], C5) + MUL64(in1[2*7], C7));
889
        tmp1[2] = in1[2*0] + FRAC_RND(MUL64(in1[2*2], C2) + 
890
                                      MUL64(in1[2*4], C4) + in6_6 + 
891
                                      MUL64(in1[2*8], C8));
892
        tmp1[4] = FRAC_RND(MUL64(in1[2*1] - in1[2*5] - in1[2*7], C3));
893
        tmp1[6] = FRAC_RND(MUL64(in1[2*2] - in1[2*4] - in1[2*8], C6)) - 
894
            in1[2*6] + in1[2*0];
895
        tmp1[8] = FRAC_RND(MUL64(in1[2*1], C5) - in3_3 - 
896
                           MUL64(in1[2*5], C7) + MUL64(in1[2*7], C1));
897
        tmp1[10] = in1[2*0] + FRAC_RND(MUL64(-in1[2*2], C8) - 
898
                                       MUL64(in1[2*4], C2) + in6_6 + 
899
                                       MUL64(in1[2*8], C4));
900
        tmp1[12] = FRAC_RND(MUL64(in1[2*1], C7) - in3_3 + 
901
                            MUL64(in1[2*5], C1) - 
902
                            MUL64(in1[2*7], C5));
903
        tmp1[14] = in1[2*0] + FRAC_RND(MUL64(-in1[2*2], C4) + 
904
                                       MUL64(in1[2*4], C8) + in6_6 - 
905
                                       MUL64(in1[2*8], C2));
906
        tmp1[16] = in1[2*0] - in1[2*2] + in1[2*4] - in1[2*6] + in1[2*8];
907
    }
908

    
909
    i = 0;
910
    for(j=0;j<4;j++) {
911
        t0 = tmp[i];
912
        t1 = tmp[i + 2];
913
        s0 = t1 + t0;
914
        s2 = t1 - t0;
915

    
916
        t2 = tmp[i + 1];
917
        t3 = tmp[i + 3];
918
        s1 = MULL(t3 + t2, icos36[j]);
919
        s3 = MULL(t3 - t2, icos36[8 - j]);
920
        
921
        t0 = MULL(s0 + s1, icos72[9 + 8 - j]);
922
        t1 = MULL(s0 - s1, icos72[8 - j]);
923
        out[18 + 9 + j] = t0;
924
        out[18 + 8 - j] = t0;
925
        out[9 + j] = -t1;
926
        out[8 - j] = t1;
927
        
928
        t0 = MULL(s2 + s3, icos72[9+j]);
929
        t1 = MULL(s2 - s3, icos72[j]);
930
        out[18 + 9 + (8 - j)] = t0;
931
        out[18 + j] = t0;
932
        out[9 + (8 - j)] = -t1;
933
        out[j] = t1;
934
        i += 4;
935
    }
936

    
937
    s0 = tmp[16];
938
    s1 = MULL(tmp[17], icos36[4]);
939
    t0 = MULL(s0 + s1, icos72[9 + 4]);
940
    t1 = MULL(s0 - s1, icos72[4]);
941
    out[18 + 9 + 4] = t0;
942
    out[18 + 8 - 4] = t0;
943
    out[9 + 4] = -t1;
944
    out[8 - 4] = t1;
945
}
946

    
947
/* fast header check for resync */
948
static int check_header(UINT32 header)
949
{
950
    /* header */
951
    if ((header & 0xffe00000) != 0xffe00000)
952
        return -1;
953
    /* layer check */
954
    if (((header >> 17) & 3) == 0)
955
        return -1;
956
    /* bit rate */
957
    if (((header >> 12) & 0xf) == 0xf)
958
        return -1;
959
    /* frequency */
960
    if (((header >> 10) & 3) == 3)
961
        return -1;
962
    return 0;
963
}
964

    
965
/* header + layer + bitrate + freq + lsf/mpeg25 */
966
#define SAME_HEADER_MASK \
967
   (0xffe00000 | (3 << 17) | (0xf << 12) | (3 << 10) | (3 << 19))
968

    
969
/* header decoding. MUST check the header before because no
970
   consistency check is done there. Return 1 if free format found and
971
   that the frame size must be computed externally */
972
static int decode_header(MPADecodeContext *s, UINT32 header)
973
{
974
    int sample_rate, frame_size, mpeg25, padding;
975
    int sample_rate_index, bitrate_index;
976
    if (header & (1<<20)) {
977
        s->lsf = (header & (1<<19)) ? 0 : 1;
978
        mpeg25 = 0;
979
    } else {
980
        s->lsf = 1;
981
        mpeg25 = 1;
982
    }
983
    
984
    s->layer = 4 - ((header >> 17) & 3);
985
    /* extract frequency */
986
    sample_rate_index = (header >> 10) & 3;
987
    sample_rate = mpa_freq_tab[sample_rate_index] >> (s->lsf + mpeg25);
988
    if (sample_rate == 0)
989
        return 1;
990
    sample_rate_index += 3 * (s->lsf + mpeg25);
991
    s->sample_rate_index = sample_rate_index;
992
    s->error_protection = ((header >> 16) & 1) ^ 1;
993

    
994
    bitrate_index = (header >> 12) & 0xf;
995
    padding = (header >> 9) & 1;
996
    //extension = (header >> 8) & 1;
997
    s->mode = (header >> 6) & 3;
998
    s->mode_ext = (header >> 4) & 3;
999
    //copyright = (header >> 3) & 1;
1000
    //original = (header >> 2) & 1;
1001
    //emphasis = header & 3;
1002

    
1003
    if (s->mode == MPA_MONO)
1004
        s->nb_channels = 1;
1005
    else
1006
        s->nb_channels = 2;
1007
    
1008
    if (bitrate_index != 0) {
1009
        frame_size = mpa_bitrate_tab[s->lsf][s->layer - 1][bitrate_index];
1010
        s->bit_rate = frame_size * 1000;
1011
        switch(s->layer) {
1012
        case 1:
1013
            frame_size = (frame_size * 12000) / sample_rate;
1014
            frame_size = (frame_size + padding) * 4;
1015
            break;
1016
        case 2:
1017
            frame_size = (frame_size * 144000) / sample_rate;
1018
            frame_size += padding;
1019
            break;
1020
        default:
1021
        case 3:
1022
            frame_size = (frame_size * 144000) / (sample_rate << s->lsf);
1023
            frame_size += padding;
1024
            break;
1025
        }
1026
        s->frame_size = frame_size;
1027
    } else {
1028
        /* if no frame size computed, signal it */
1029
        if (!s->free_format_frame_size)
1030
            return 1;
1031
        /* free format: compute bitrate and real frame size from the
1032
           frame size we extracted by reading the bitstream */
1033
        s->frame_size = s->free_format_frame_size;
1034
        switch(s->layer) {
1035
        case 1:
1036
            s->frame_size += padding  * 4;
1037
            s->bit_rate = (s->frame_size * sample_rate) / 48000;
1038
            break;
1039
        case 2:
1040
            s->frame_size += padding;
1041
            s->bit_rate = (s->frame_size * sample_rate) / 144000;
1042
            break;
1043
        default:
1044
        case 3:
1045
            s->frame_size += padding;
1046
            s->bit_rate = (s->frame_size * (sample_rate << s->lsf)) / 144000;
1047
            break;
1048
        }
1049
    }
1050
    s->sample_rate = sample_rate;
1051
    
1052
#ifdef DEBUG
1053
    printf("layer%d, %d Hz, %d kbits/s, ",
1054
           s->layer, s->sample_rate, s->bit_rate);
1055
    if (s->nb_channels == 2) {
1056
        if (s->layer == 3) {
1057
            if (s->mode_ext & MODE_EXT_MS_STEREO)
1058
                printf("ms-");
1059
            if (s->mode_ext & MODE_EXT_I_STEREO)
1060
                printf("i-");
1061
        }
1062
        printf("stereo");
1063
    } else {
1064
        printf("mono");
1065
    }
1066
    printf("\n");
1067
#endif
1068
    return 0;
1069
}
1070

    
1071
/* return the number of decoded frames */
1072
static int mp_decode_layer1(MPADecodeContext *s)
1073
{
1074
    int bound, i, v, n, ch, j, mant;
1075
    UINT8 allocation[MPA_MAX_CHANNELS][SBLIMIT];
1076
    UINT8 scale_factors[MPA_MAX_CHANNELS][SBLIMIT];
1077

    
1078
    if (s->mode == MPA_JSTEREO) 
1079
        bound = (s->mode_ext + 1) * 4;
1080
    else
1081
        bound = SBLIMIT;
1082

    
1083
    /* allocation bits */
1084
    for(i=0;i<bound;i++) {
1085
        for(ch=0;ch<s->nb_channels;ch++) {
1086
            allocation[ch][i] = get_bits(&s->gb, 4);
1087
        }
1088
    }
1089
    for(i=bound;i<SBLIMIT;i++) {
1090
        allocation[0][i] = get_bits(&s->gb, 4);
1091
    }
1092

    
1093
    /* scale factors */
1094
    for(i=0;i<bound;i++) {
1095
        for(ch=0;ch<s->nb_channels;ch++) {
1096
            if (allocation[ch][i])
1097
                scale_factors[ch][i] = get_bits(&s->gb, 6);
1098
        }
1099
    }
1100
    for(i=bound;i<SBLIMIT;i++) {
1101
        if (allocation[0][i]) {
1102
            scale_factors[0][i] = get_bits(&s->gb, 6);
1103
            scale_factors[1][i] = get_bits(&s->gb, 6);
1104
        }
1105
    }
1106
    
1107
    /* compute samples */
1108
    for(j=0;j<12;j++) {
1109
        for(i=0;i<bound;i++) {
1110
            for(ch=0;ch<s->nb_channels;ch++) {
1111
                n = allocation[ch][i];
1112
                if (n) {
1113
                    mant = get_bits(&s->gb, n + 1);
1114
                    v = l1_unscale(n, mant, scale_factors[ch][i]);
1115
                } else {
1116
                    v = 0;
1117
                }
1118
                s->sb_samples[ch][j][i] = v;
1119
            }
1120
        }
1121
        for(i=bound;i<SBLIMIT;i++) {
1122
            n = allocation[0][i];
1123
            if (n) {
1124
                mant = get_bits(&s->gb, n + 1);
1125
                v = l1_unscale(n, mant, scale_factors[0][i]);
1126
                s->sb_samples[0][j][i] = v;
1127
                v = l1_unscale(n, mant, scale_factors[1][i]);
1128
                s->sb_samples[1][j][i] = v;
1129
            } else {
1130
                s->sb_samples[0][j][i] = 0;
1131
                s->sb_samples[1][j][i] = 0;
1132
            }
1133
        }
1134
    }
1135
    return 12;
1136
}
1137

    
1138
/* bitrate is in kb/s */
1139
int l2_select_table(int bitrate, int nb_channels, int freq, int lsf)
1140
{
1141
    int ch_bitrate, table;
1142
    
1143
    ch_bitrate = bitrate / nb_channels;
1144
    if (!lsf) {
1145
        if ((freq == 48000 && ch_bitrate >= 56) ||
1146
            (ch_bitrate >= 56 && ch_bitrate <= 80)) 
1147
            table = 0;
1148
        else if (freq != 48000 && ch_bitrate >= 96) 
1149
            table = 1;
1150
        else if (freq != 32000 && ch_bitrate <= 48) 
1151
            table = 2;
1152
        else 
1153
            table = 3;
1154
    } else {
1155
        table = 4;
1156
    }
1157
    return table;
1158
}
1159

    
1160
static int mp_decode_layer2(MPADecodeContext *s)
1161
{
1162
    int sblimit; /* number of used subbands */
1163
    const unsigned char *alloc_table;
1164
    int table, bit_alloc_bits, i, j, ch, bound, v;
1165
    unsigned char bit_alloc[MPA_MAX_CHANNELS][SBLIMIT];
1166
    unsigned char scale_code[MPA_MAX_CHANNELS][SBLIMIT];
1167
    unsigned char scale_factors[MPA_MAX_CHANNELS][SBLIMIT][3], *sf;
1168
    int scale, qindex, bits, steps, k, l, m, b;
1169

    
1170
    /* select decoding table */
1171
    table = l2_select_table(s->bit_rate / 1000, s->nb_channels, 
1172
                            s->sample_rate, s->lsf);
1173
    sblimit = sblimit_table[table];
1174
    alloc_table = alloc_tables[table];
1175

    
1176
    if (s->mode == MPA_JSTEREO) 
1177
        bound = (s->mode_ext + 1) * 4;
1178
    else
1179
        bound = sblimit;
1180

    
1181
    dprintf("bound=%d sblimit=%d\n", bound, sblimit);
1182
    /* parse bit allocation */
1183
    j = 0;
1184
    for(i=0;i<bound;i++) {
1185
        bit_alloc_bits = alloc_table[j];
1186
        for(ch=0;ch<s->nb_channels;ch++) {
1187
            bit_alloc[ch][i] = get_bits(&s->gb, bit_alloc_bits);
1188
        }
1189
        j += 1 << bit_alloc_bits;
1190
    }
1191
    for(i=bound;i<sblimit;i++) {
1192
        bit_alloc_bits = alloc_table[j];
1193
        v = get_bits(&s->gb, bit_alloc_bits);
1194
        bit_alloc[0][i] = v;
1195
        bit_alloc[1][i] = v;
1196
        j += 1 << bit_alloc_bits;
1197
    }
1198

    
1199
#ifdef DEBUG
1200
    {
1201
        for(ch=0;ch<s->nb_channels;ch++) {
1202
            for(i=0;i<sblimit;i++)
1203
                printf(" %d", bit_alloc[ch][i]);
1204
            printf("\n");
1205
        }
1206
    }
1207
#endif
1208

    
1209
    /* scale codes */
1210
    for(i=0;i<sblimit;i++) {
1211
        for(ch=0;ch<s->nb_channels;ch++) {
1212
            if (bit_alloc[ch][i]) 
1213
                scale_code[ch][i] = get_bits(&s->gb, 2);
1214
        }
1215
    }
1216
    
1217
    /* scale factors */
1218
    for(i=0;i<sblimit;i++) {
1219
        for(ch=0;ch<s->nb_channels;ch++) {
1220
            if (bit_alloc[ch][i]) {
1221
                sf = scale_factors[ch][i];
1222
                switch(scale_code[ch][i]) {
1223
                default:
1224
                case 0:
1225
                    sf[0] = get_bits(&s->gb, 6);
1226
                    sf[1] = get_bits(&s->gb, 6);
1227
                    sf[2] = get_bits(&s->gb, 6);
1228
                    break;
1229
                case 2:
1230
                    sf[0] = get_bits(&s->gb, 6);
1231
                    sf[1] = sf[0];
1232
                    sf[2] = sf[0];
1233
                    break;
1234
                case 1:
1235
                    sf[0] = get_bits(&s->gb, 6);
1236
                    sf[2] = get_bits(&s->gb, 6);
1237
                    sf[1] = sf[0];
1238
                    break;
1239
                case 3:
1240
                    sf[0] = get_bits(&s->gb, 6);
1241
                    sf[2] = get_bits(&s->gb, 6);
1242
                    sf[1] = sf[2];
1243
                    break;
1244
                }
1245
            }
1246
        }
1247
    }
1248

    
1249
#ifdef DEBUG
1250
    for(ch=0;ch<s->nb_channels;ch++) {
1251
        for(i=0;i<sblimit;i++) {
1252
            if (bit_alloc[ch][i]) {
1253
                sf = scale_factors[ch][i];
1254
                printf(" %d %d %d", sf[0], sf[1], sf[2]);
1255
            } else {
1256
                printf(" -");
1257
            }
1258
        }
1259
        printf("\n");
1260
    }
1261
#endif
1262

    
1263
    /* samples */
1264
    for(k=0;k<3;k++) {
1265
        for(l=0;l<12;l+=3) {
1266
            j = 0;
1267
            for(i=0;i<bound;i++) {
1268
                bit_alloc_bits = alloc_table[j];
1269
                for(ch=0;ch<s->nb_channels;ch++) {
1270
                    b = bit_alloc[ch][i];
1271
                    if (b) {
1272
                        scale = scale_factors[ch][i][k];
1273
                        qindex = alloc_table[j+b];
1274
                        bits = quant_bits[qindex];
1275
                        if (bits < 0) {
1276
                            /* 3 values at the same time */
1277
                            v = get_bits(&s->gb, -bits);
1278
                            steps = quant_steps[qindex];
1279
                            s->sb_samples[ch][k * 12 + l + 0][i] = 
1280
                                l2_unscale_group(steps, v % steps, scale);
1281
                            v = v / steps;
1282
                            s->sb_samples[ch][k * 12 + l + 1][i] = 
1283
                                l2_unscale_group(steps, v % steps, scale);
1284
                            v = v / steps;
1285
                            s->sb_samples[ch][k * 12 + l + 2][i] = 
1286
                                l2_unscale_group(steps, v, scale);
1287
                        } else {
1288
                            for(m=0;m<3;m++) {
1289
                                v = get_bits(&s->gb, bits);
1290
                                v = l1_unscale(bits - 1, v, scale);
1291
                                s->sb_samples[ch][k * 12 + l + m][i] = v;
1292
                            }
1293
                        }
1294
                    } else {
1295
                        s->sb_samples[ch][k * 12 + l + 0][i] = 0;
1296
                        s->sb_samples[ch][k * 12 + l + 1][i] = 0;
1297
                        s->sb_samples[ch][k * 12 + l + 2][i] = 0;
1298
                    }
1299
                }
1300
                /* next subband in alloc table */
1301
                j += 1 << bit_alloc_bits; 
1302
            }
1303
            /* XXX: find a way to avoid this duplication of code */
1304
            for(i=bound;i<sblimit;i++) {
1305
                bit_alloc_bits = alloc_table[j];
1306
                b = bit_alloc[0][i];
1307
                if (b) {
1308
                    int mant, scale0, scale1;
1309
                    scale0 = scale_factors[0][i][k];
1310
                    scale1 = scale_factors[1][i][k];
1311
                    qindex = alloc_table[j+b];
1312
                    bits = quant_bits[qindex];
1313
                    if (bits < 0) {
1314
                        /* 3 values at the same time */
1315
                        v = get_bits(&s->gb, -bits);
1316
                        steps = quant_steps[qindex];
1317
                        mant = v % steps;
1318
                        v = v / steps;
1319
                        s->sb_samples[0][k * 12 + l + 0][i] = 
1320
                            l2_unscale_group(steps, mant, scale0);
1321
                        s->sb_samples[1][k * 12 + l + 0][i] = 
1322
                            l2_unscale_group(steps, mant, scale1);
1323
                        mant = v % steps;
1324
                        v = v / steps;
1325
                        s->sb_samples[0][k * 12 + l + 1][i] = 
1326
                            l2_unscale_group(steps, mant, scale0);
1327
                        s->sb_samples[1][k * 12 + l + 1][i] = 
1328
                            l2_unscale_group(steps, mant, scale1);
1329
                        s->sb_samples[0][k * 12 + l + 2][i] = 
1330
                            l2_unscale_group(steps, v, scale0);
1331
                        s->sb_samples[1][k * 12 + l + 2][i] = 
1332
                            l2_unscale_group(steps, v, scale1);
1333
                    } else {
1334
                        for(m=0;m<3;m++) {
1335
                            mant = get_bits(&s->gb, bits);
1336
                            s->sb_samples[0][k * 12 + l + m][i] = 
1337
                                l1_unscale(bits - 1, mant, scale0);
1338
                            s->sb_samples[1][k * 12 + l + m][i] = 
1339
                                l1_unscale(bits - 1, mant, scale1);
1340
                        }
1341
                    }
1342
                } else {
1343
                    s->sb_samples[0][k * 12 + l + 0][i] = 0;
1344
                    s->sb_samples[0][k * 12 + l + 1][i] = 0;
1345
                    s->sb_samples[0][k * 12 + l + 2][i] = 0;
1346
                    s->sb_samples[1][k * 12 + l + 0][i] = 0;
1347
                    s->sb_samples[1][k * 12 + l + 1][i] = 0;
1348
                    s->sb_samples[1][k * 12 + l + 2][i] = 0;
1349
                }
1350
                /* next subband in alloc table */
1351
                j += 1 << bit_alloc_bits; 
1352
            }
1353
            /* fill remaining samples to zero */
1354
            for(i=sblimit;i<SBLIMIT;i++) {
1355
                for(ch=0;ch<s->nb_channels;ch++) {
1356
                    s->sb_samples[ch][k * 12 + l + 0][i] = 0;
1357
                    s->sb_samples[ch][k * 12 + l + 1][i] = 0;
1358
                    s->sb_samples[ch][k * 12 + l + 2][i] = 0;
1359
                }
1360
            }
1361
        }
1362
    }
1363
    return 3 * 12;
1364
}
1365

    
1366
/*
1367
 * Seek back in the stream for backstep bytes (at most 511 bytes)
1368
 */
1369
static void seek_to_maindata(MPADecodeContext *s, long backstep)
1370
{
1371
    UINT8 *ptr;
1372

    
1373
    /* compute current position in stream */
1374
#ifdef ALT_BITSTREAM_READER
1375
    ptr = s->gb.buffer + (s->gb.index>>3);
1376
#else
1377
    ptr = s->gb.buf_ptr - (s->gb.bit_cnt >> 3);
1378
#endif    
1379
    /* copy old data before current one */
1380
    ptr -= backstep;
1381
    memcpy(ptr, s->inbuf1[s->inbuf_index ^ 1] + 
1382
           BACKSTEP_SIZE + s->old_frame_size - backstep, backstep);
1383
    /* init get bits again */
1384
    init_get_bits(&s->gb, ptr, s->frame_size + backstep);
1385

    
1386
    /* prepare next buffer */
1387
    s->inbuf_index ^= 1;
1388
    s->inbuf = &s->inbuf1[s->inbuf_index][BACKSTEP_SIZE];
1389
    s->old_frame_size = s->frame_size;
1390
}
1391

    
1392
static inline void lsf_sf_expand(int *slen,
1393
                                 int sf, int n1, int n2, int n3)
1394
{
1395
    if (n3) {
1396
        slen[3] = sf % n3;
1397
        sf /= n3;
1398
    } else {
1399
        slen[3] = 0;
1400
    }
1401
    if (n2) {
1402
        slen[2] = sf % n2;
1403
        sf /= n2;
1404
    } else {
1405
        slen[2] = 0;
1406
    }
1407
    slen[1] = sf % n1;
1408
    sf /= n1;
1409
    slen[0] = sf;
1410
}
1411

    
1412
static void exponents_from_scale_factors(MPADecodeContext *s, 
1413
                                         GranuleDef *g,
1414
                                         INT16 *exponents)
1415
{
1416
    const UINT8 *bstab, *pretab;
1417
    int len, i, j, k, l, v0, shift, gain, gains[3];
1418
    INT16 *exp_ptr;
1419

    
1420
    exp_ptr = exponents;
1421
    gain = g->global_gain - 210;
1422
    shift = g->scalefac_scale + 1;
1423

    
1424
    bstab = band_size_long[s->sample_rate_index];
1425
    pretab = mpa_pretab[g->preflag];
1426
    for(i=0;i<g->long_end;i++) {
1427
        v0 = gain - ((g->scale_factors[i] + pretab[i]) << shift);
1428
        len = bstab[i];
1429
        for(j=len;j>0;j--)
1430
            *exp_ptr++ = v0;
1431
    }
1432

    
1433
    if (g->short_start < 13) {
1434
        bstab = band_size_short[s->sample_rate_index];
1435
        gains[0] = gain - (g->subblock_gain[0] << 3);
1436
        gains[1] = gain - (g->subblock_gain[1] << 3);
1437
        gains[2] = gain - (g->subblock_gain[2] << 3);
1438
        k = g->long_end;
1439
        for(i=g->short_start;i<13;i++) {
1440
            len = bstab[i];
1441
            for(l=0;l<3;l++) {
1442
                v0 = gains[l] - (g->scale_factors[k++] << shift);
1443
                for(j=len;j>0;j--)
1444
                *exp_ptr++ = v0;
1445
            }
1446
        }
1447
    }
1448
}
1449

    
1450
/* handle n = 0 too */
1451
static inline int get_bitsz(GetBitContext *s, int n)
1452
{
1453
    if (n == 0)
1454
        return 0;
1455
    else
1456
        return get_bits(s, n);
1457
}
1458

    
1459
static int huffman_decode(MPADecodeContext *s, GranuleDef *g,
1460
                          INT16 *exponents, int end_pos)
1461
{
1462
    int s_index;
1463
    int linbits, code, x, y, l, v, i, j, k, pos;
1464
    UINT8 *last_buf_ptr;
1465
    UINT32 last_bit_buf;
1466
    int last_bit_cnt;
1467
    VLC *vlc;
1468
    UINT8 *code_table;
1469

    
1470
    /* low frequencies (called big values) */
1471
    s_index = 0;
1472
    for(i=0;i<3;i++) {
1473
        j = g->region_size[i];
1474
        if (j == 0)
1475
            continue;
1476
        /* select vlc table */
1477
        k = g->table_select[i];
1478
        l = mpa_huff_data[k][0];
1479
        linbits = mpa_huff_data[k][1];
1480
        vlc = &huff_vlc[l];
1481
        code_table = huff_code_table[l];
1482

    
1483
        /* read huffcode and compute each couple */
1484
        for(;j>0;j--) {
1485
            if (get_bits_count(&s->gb) >= end_pos)
1486
                break;
1487
            if (code_table) {
1488
                code = get_vlc(&s->gb, vlc);
1489
                if (code < 0)
1490
                    return -1;
1491
                y = code_table[code];
1492
                x = y >> 4;
1493
                y = y & 0x0f;
1494
            } else {
1495
                x = 0;
1496
                y = 0;
1497
            }
1498
            dprintf("region=%d n=%d x=%d y=%d exp=%d\n", 
1499
                    i, g->region_size[i] - j, x, y, exponents[s_index]);
1500
            if (x) {
1501
                if (x == 15)
1502
                    x += get_bitsz(&s->gb, linbits);
1503
                v = l3_unscale(x, exponents[s_index]);
1504
                if (get_bits1(&s->gb))
1505
                    v = -v;
1506
            } else {
1507
                v = 0;
1508
            }
1509
            g->sb_hybrid[s_index++] = v;
1510
            if (y) {
1511
                if (y == 15)
1512
                    y += get_bitsz(&s->gb, linbits);
1513
                v = l3_unscale(y, exponents[s_index]);
1514
                if (get_bits1(&s->gb))
1515
                    v = -v;
1516
            } else {
1517
                v = 0;
1518
            }
1519
            g->sb_hybrid[s_index++] = v;
1520
        }
1521
    }
1522
            
1523
    /* high frequencies */
1524
    vlc = &huff_quad_vlc[g->count1table_select];
1525
    last_buf_ptr = NULL;
1526
    last_bit_buf = 0;
1527
    last_bit_cnt = 0;
1528
    while (s_index <= 572) {
1529
        pos = get_bits_count(&s->gb);
1530
        if (pos >= end_pos) {
1531
            if (pos > end_pos && last_buf_ptr != NULL) {
1532
                /* some encoders generate an incorrect size for this
1533
                   part. We must go back into the data */
1534
                s_index -= 4;
1535
#ifdef ALT_BITSTREAM_READER
1536
                s->gb.buffer = last_buf_ptr;
1537
                s->gb.index = last_bit_cnt;
1538
#else
1539
                s->gb.buf_ptr = last_buf_ptr;
1540
                s->gb.bit_buf = last_bit_buf;
1541
                s->gb.bit_cnt = last_bit_cnt;
1542
#endif            
1543
            }
1544
            break;
1545
        }
1546
#ifdef ALT_BITSTREAM_READER
1547
        last_buf_ptr = s->gb.buffer;
1548
        last_bit_cnt = s->gb.index;
1549
#else
1550
        last_buf_ptr = s->gb.buf_ptr;
1551
        last_bit_buf = s->gb.bit_buf;
1552
        last_bit_cnt = s->gb.bit_cnt;
1553
#endif
1554
        
1555
        code = get_vlc(&s->gb, vlc);
1556
        dprintf("t=%d code=%d\n", g->count1table_select, code);
1557
        if (code < 0)
1558
            return -1;
1559
        for(i=0;i<4;i++) {
1560
            if (code & (8 >> i)) {
1561
                /* non zero value. Could use a hand coded function for
1562
                   'one' value */
1563
                v = l3_unscale(1, exponents[s_index]);
1564
                if(get_bits1(&s->gb))
1565
                    v = -v;
1566
            } else {
1567
                v = 0;
1568
            }
1569
            g->sb_hybrid[s_index++] = v;
1570
        }
1571
    }
1572
    while (s_index < 576)
1573
        g->sb_hybrid[s_index++] = 0;
1574
    return 0;
1575
}
1576

    
1577
/* Reorder short blocks from bitstream order to interleaved order. It
1578
   would be faster to do it in parsing, but the code would be far more
1579
   complicated */
1580
static void reorder_block(MPADecodeContext *s, GranuleDef *g)
1581
{
1582
    int i, j, k, len;
1583
    INT32 *ptr, *dst, *ptr1;
1584
    INT32 tmp[576];
1585

    
1586
    if (g->block_type != 2)
1587
        return;
1588

    
1589
    if (g->switch_point) {
1590
        if (s->sample_rate_index != 8) {
1591
            ptr = g->sb_hybrid + 36;
1592
        } else {
1593
            ptr = g->sb_hybrid + 48;
1594
        }
1595
    } else {
1596
        ptr = g->sb_hybrid;
1597
    }
1598
    
1599
    for(i=g->short_start;i<13;i++) {
1600
        len = band_size_short[s->sample_rate_index][i];
1601
        ptr1 = ptr;
1602
        for(k=0;k<3;k++) {
1603
            dst = tmp + k;
1604
            for(j=len;j>0;j--) {
1605
                *dst = *ptr++;
1606
                dst += 3;
1607
            }
1608
        }
1609
        memcpy(ptr1, tmp, len * 3 * sizeof(INT32));
1610
    }
1611
}
1612

    
1613
#define ISQRT2 FIXR(0.70710678118654752440)
1614

    
1615
static void compute_stereo(MPADecodeContext *s,
1616
                           GranuleDef *g0, GranuleDef *g1)
1617
{
1618
    int i, j, k, l;
1619
    INT32 v1, v2;
1620
    int sf_max, tmp0, tmp1, sf, len, non_zero_found;
1621
    INT32 (*is_tab)[16];
1622
    INT32 *tab0, *tab1;
1623
    int non_zero_found_short[3];
1624

    
1625
    /* intensity stereo */
1626
    if (s->mode_ext & MODE_EXT_I_STEREO) {
1627
        if (!s->lsf) {
1628
            is_tab = is_table;
1629
            sf_max = 7;
1630
        } else {
1631
            is_tab = is_table_lsf[g1->scalefac_compress & 1];
1632
            sf_max = 16;
1633
        }
1634
            
1635
        tab0 = g0->sb_hybrid + 576;
1636
        tab1 = g1->sb_hybrid + 576;
1637

    
1638
        non_zero_found_short[0] = 0;
1639
        non_zero_found_short[1] = 0;
1640
        non_zero_found_short[2] = 0;
1641
        k = (13 - g1->short_start) * 3 + g1->long_end - 3;
1642
        for(i = 12;i >= g1->short_start;i--) {
1643
            /* for last band, use previous scale factor */
1644
            if (i != 11)
1645
                k -= 3;
1646
            len = band_size_short[s->sample_rate_index][i];
1647
            for(l=2;l>=0;l--) {
1648
                tab0 -= len;
1649
                tab1 -= len;
1650
                if (!non_zero_found_short[l]) {
1651
                    /* test if non zero band. if so, stop doing i-stereo */
1652
                    for(j=0;j<len;j++) {
1653
                        if (tab1[j] != 0) {
1654
                            non_zero_found_short[l] = 1;
1655
                            goto found1;
1656
                        }
1657
                    }
1658
                    sf = g1->scale_factors[k + l];
1659
                    if (sf >= sf_max)
1660
                        goto found1;
1661

    
1662
                    v1 = is_tab[0][sf];
1663
                    v2 = is_tab[1][sf];
1664
                    for(j=0;j<len;j++) {
1665
                        tmp0 = tab0[j];
1666
                        tab0[j] = MULL(tmp0, v1);
1667
                        tab1[j] = MULL(tmp0, v2);
1668
                    }
1669
                } else {
1670
                found1:
1671
                    if (s->mode_ext & MODE_EXT_MS_STEREO) {
1672
                        /* lower part of the spectrum : do ms stereo
1673
                           if enabled */
1674
                        for(j=0;j<len;j++) {
1675
                            tmp0 = tab0[j];
1676
                            tmp1 = tab1[j];
1677
                            tab0[j] = MULL(tmp0 + tmp1, ISQRT2);
1678
                            tab1[j] = MULL(tmp0 - tmp1, ISQRT2);
1679
                        }
1680
                    }
1681
                }
1682
            }
1683
        }
1684

    
1685
        non_zero_found = non_zero_found_short[0] | 
1686
            non_zero_found_short[1] | 
1687
            non_zero_found_short[2];
1688

    
1689
        for(i = g1->long_end - 1;i >= 0;i--) {
1690
            len = band_size_long[s->sample_rate_index][i];
1691
            tab0 -= len;
1692
            tab1 -= len;
1693
            /* test if non zero band. if so, stop doing i-stereo */
1694
            if (!non_zero_found) {
1695
                for(j=0;j<len;j++) {
1696
                    if (tab1[j] != 0) {
1697
                        non_zero_found = 1;
1698
                        goto found2;
1699
                    }
1700
                }
1701
                /* for last band, use previous scale factor */
1702
                k = (i == 21) ? 20 : i;
1703
                sf = g1->scale_factors[k];
1704
                if (sf >= sf_max)
1705
                    goto found2;
1706
                v1 = is_tab[0][sf];
1707
                v2 = is_tab[1][sf];
1708
                for(j=0;j<len;j++) {
1709
                    tmp0 = tab0[j];
1710
                    tab0[j] = MULL(tmp0, v1);
1711
                    tab1[j] = MULL(tmp0, v2);
1712
                }
1713
            } else {
1714
            found2:
1715
                if (s->mode_ext & MODE_EXT_MS_STEREO) {
1716
                    /* lower part of the spectrum : do ms stereo
1717
                       if enabled */
1718
                    for(j=0;j<len;j++) {
1719
                        tmp0 = tab0[j];
1720
                        tmp1 = tab1[j];
1721
                        tab0[j] = MULL(tmp0 + tmp1, ISQRT2);
1722
                        tab1[j] = MULL(tmp0 - tmp1, ISQRT2);
1723
                    }
1724
                }
1725
            }
1726
        }
1727
    } else if (s->mode_ext & MODE_EXT_MS_STEREO) {
1728
        /* ms stereo ONLY */
1729
        /* NOTE: the 1/sqrt(2) normalization factor is included in the
1730
           global gain */
1731
        tab0 = g0->sb_hybrid;
1732
        tab1 = g1->sb_hybrid;
1733
        for(i=0;i<576;i++) {
1734
            tmp0 = tab0[i];
1735
            tmp1 = tab1[i];
1736
            tab0[i] = tmp0 + tmp1;
1737
            tab1[i] = tmp0 - tmp1;
1738
        }
1739
    }
1740
}
1741

    
1742
static void compute_antialias(MPADecodeContext *s,
1743
                              GranuleDef *g)
1744
{
1745
    INT32 *ptr, *p0, *p1, *csa;
1746
    int n, tmp0, tmp1, i, j;
1747

    
1748
    /* we antialias only "long" bands */
1749
    if (g->block_type == 2) {
1750
        if (!g->switch_point)
1751
            return;
1752
        /* XXX: check this for 8000Hz case */
1753
        n = 1;
1754
    } else {
1755
        n = SBLIMIT - 1;
1756
    }
1757
    
1758
    ptr = g->sb_hybrid + 18;
1759
    for(i = n;i > 0;i--) {
1760
        p0 = ptr - 1;
1761
        p1 = ptr;
1762
        csa = &csa_table[0][0];
1763
        for(j=0;j<8;j++) {
1764
            tmp0 = *p0;
1765
            tmp1 = *p1;
1766
            *p0 = FRAC_RND(MUL64(tmp0, csa[0]) - MUL64(tmp1, csa[1]));
1767
            *p1 = FRAC_RND(MUL64(tmp0, csa[1]) + MUL64(tmp1, csa[0]));
1768
            p0--;
1769
            p1++;
1770
            csa += 2;
1771
        }
1772
        ptr += 18;
1773
    }
1774
}
1775

    
1776
static void compute_imdct(MPADecodeContext *s,
1777
                          GranuleDef *g, 
1778
                          INT32 *sb_samples,
1779
                          INT32 *mdct_buf)
1780
{
1781
    INT32 *ptr, *win, *win1, *buf, *buf2, *out_ptr, *ptr1;
1782
    INT32 in[6];
1783
    INT32 out[36];
1784
    INT32 out2[12];
1785
    int i, j, k, mdct_long_end, v, sblimit;
1786

    
1787
    /* find last non zero block */
1788
    ptr = g->sb_hybrid + 576;
1789
    ptr1 = g->sb_hybrid + 2 * 18;
1790
    while (ptr >= ptr1) {
1791
        ptr -= 6;
1792
        v = ptr[0] | ptr[1] | ptr[2] | ptr[3] | ptr[4] | ptr[5];
1793
        if (v != 0)
1794
            break;
1795
    }
1796
    sblimit = ((ptr - g->sb_hybrid) / 18) + 1;
1797

    
1798
    if (g->block_type == 2) {
1799
        /* XXX: check for 8000 Hz */
1800
        if (g->switch_point)
1801
            mdct_long_end = 2;
1802
        else
1803
            mdct_long_end = 0;
1804
    } else {
1805
        mdct_long_end = sblimit;
1806
    }
1807

    
1808
    buf = mdct_buf;
1809
    ptr = g->sb_hybrid;
1810
    for(j=0;j<mdct_long_end;j++) {
1811
        imdct36(out, ptr);
1812
        /* apply window & overlap with previous buffer */
1813
        out_ptr = sb_samples + j;
1814
        /* select window */
1815
        if (g->switch_point && j < 2)
1816
            win1 = mdct_win[0];
1817
        else
1818
            win1 = mdct_win[g->block_type];
1819
        /* select frequency inversion */
1820
        win = win1 + ((4 * 36) & -(j & 1));
1821
        for(i=0;i<18;i++) {
1822
            *out_ptr = MULL(out[i], win[i]) + buf[i];
1823
            buf[i] = MULL(out[i + 18], win[i + 18]);
1824
            out_ptr += SBLIMIT;
1825
        }
1826
        ptr += 18;
1827
        buf += 18;
1828
    }
1829
    for(j=mdct_long_end;j<sblimit;j++) {
1830
        for(i=0;i<6;i++) {
1831
            out[i] = 0;
1832
            out[6 + i] = 0;
1833
            out[30+i] = 0;
1834
        }
1835
        /* select frequency inversion */
1836
        win = mdct_win[2] + ((4 * 36) & -(j & 1));
1837
        buf2 = out + 6;
1838
        for(k=0;k<3;k++) {
1839
            /* reorder input for short mdct */
1840
            ptr1 = ptr + k;
1841
            for(i=0;i<6;i++) {
1842
                in[i] = *ptr1;
1843
                ptr1 += 3;
1844
            }
1845
            imdct12(out2, in);
1846
            /* apply 12 point window and do small overlap */
1847
            for(i=0;i<6;i++) {
1848
                buf2[i] = MULL(out2[i], win[i]) + buf2[i];
1849
                buf2[i + 6] = MULL(out2[i + 6], win[i + 6]);
1850
            }
1851
            buf2 += 6;
1852
        }
1853
        /* overlap */
1854
        out_ptr = sb_samples + j;
1855
        for(i=0;i<18;i++) {
1856
            *out_ptr = out[i] + buf[i];
1857
            buf[i] = out[i + 18];
1858
            out_ptr += SBLIMIT;
1859
        }
1860
        ptr += 18;
1861
        buf += 18;
1862
    }
1863
    /* zero bands */
1864
    for(j=sblimit;j<SBLIMIT;j++) {
1865
        /* overlap */
1866
        out_ptr = sb_samples + j;
1867
        for(i=0;i<18;i++) {
1868
            *out_ptr = buf[i];
1869
            buf[i] = 0;
1870
            out_ptr += SBLIMIT;
1871
        }
1872
        buf += 18;
1873
    }
1874
}
1875

    
1876
#ifdef DEBUG
1877
void sample_dump(int fnum, INT32 *tab, int n)
1878
{
1879
    static FILE *files[16], *f;
1880
    char buf[512];
1881

    
1882
    f = files[fnum];
1883
    if (!f) {
1884
        sprintf(buf, "/tmp/out%d.pcm", fnum);
1885
        f = fopen(buf, "w");
1886
        if (!f)
1887
            return;
1888
        files[fnum] = f;
1889
    }
1890
    
1891
    if (fnum == 0) {
1892
        int i;
1893
        static int pos = 0;
1894
        printf("pos=%d\n", pos);
1895
        for(i=0;i<n;i++) {
1896
            printf(" %f", (double)tab[i] / 32768.0);
1897
            if ((i % 18) == 17)
1898
                printf("\n");
1899
        }
1900
        pos += n;
1901
    }
1902

    
1903
    fwrite(tab, 1, n * sizeof(INT32), f);
1904
}
1905
#endif
1906

    
1907

    
1908
/* main layer3 decoding function */
1909
static int mp_decode_layer3(MPADecodeContext *s)
1910
{
1911
    int nb_granules, main_data_begin, private_bits;
1912
    int gr, ch, blocksplit_flag, i, j, k, n, bits_pos, bits_left;
1913
    GranuleDef granules[2][2], *g;
1914
    INT16 exponents[576];
1915

    
1916
    /* read side info */
1917
    if (s->lsf) {
1918
        main_data_begin = get_bits(&s->gb, 8);
1919
        if (s->nb_channels == 2)
1920
            private_bits = get_bits(&s->gb, 2);
1921
        else
1922
            private_bits = get_bits(&s->gb, 1);
1923
        nb_granules = 1;
1924
    } else {
1925
        main_data_begin = get_bits(&s->gb, 9);
1926
        if (s->nb_channels == 2)
1927
            private_bits = get_bits(&s->gb, 3);
1928
        else
1929
            private_bits = get_bits(&s->gb, 5);
1930
        nb_granules = 2;
1931
        for(ch=0;ch<s->nb_channels;ch++) {
1932
            granules[ch][0].scfsi = 0; /* all scale factors are transmitted */
1933
            granules[ch][1].scfsi = get_bits(&s->gb, 4);
1934
        }
1935
    }
1936
    
1937
    for(gr=0;gr<nb_granules;gr++) {
1938
        for(ch=0;ch<s->nb_channels;ch++) {
1939
            dprintf("gr=%d ch=%d: side_info\n", gr, ch);
1940
            g = &granules[ch][gr];
1941
            g->part2_3_length = get_bits(&s->gb, 12);
1942
            g->big_values = get_bits(&s->gb, 9);
1943
            g->global_gain = get_bits(&s->gb, 8);
1944
            /* if MS stereo only is selected, we precompute the
1945
               1/sqrt(2) renormalization factor */
1946
            if ((s->mode_ext & (MODE_EXT_MS_STEREO | MODE_EXT_I_STEREO)) == 
1947
                MODE_EXT_MS_STEREO)
1948
                g->global_gain -= 2;
1949
            if (s->lsf)
1950
                g->scalefac_compress = get_bits(&s->gb, 9);
1951
            else
1952
                g->scalefac_compress = get_bits(&s->gb, 4);
1953
            blocksplit_flag = get_bits(&s->gb, 1);
1954
            if (blocksplit_flag) {
1955
                g->block_type = get_bits(&s->gb, 2);
1956
                if (g->block_type == 0)
1957
                    return -1;
1958
                g->switch_point = get_bits(&s->gb, 1);
1959
                for(i=0;i<2;i++)
1960
                    g->table_select[i] = get_bits(&s->gb, 5);
1961
                for(i=0;i<3;i++) 
1962
                    g->subblock_gain[i] = get_bits(&s->gb, 3);
1963
                /* compute huffman coded region sizes */
1964
                if (g->block_type == 2)
1965
                    g->region_size[0] = (36 / 2);
1966
                else {
1967
                    if (s->sample_rate_index <= 2) 
1968
                        g->region_size[0] = (36 / 2);
1969
                    else if (s->sample_rate_index != 8) 
1970
                        g->region_size[0] = (54 / 2);
1971
                    else
1972
                        g->region_size[0] = (108 / 2);
1973
                }
1974
                g->region_size[1] = (576 / 2);
1975
            } else {
1976
                int region_address1, region_address2, l;
1977
                g->block_type = 0;
1978
                g->switch_point = 0;
1979
                for(i=0;i<3;i++)
1980
                    g->table_select[i] = get_bits(&s->gb, 5);
1981
                /* compute huffman coded region sizes */
1982
                region_address1 = get_bits(&s->gb, 4);
1983
                region_address2 = get_bits(&s->gb, 3);
1984
                dprintf("region1=%d region2=%d\n", 
1985
                        region_address1, region_address2);
1986
                g->region_size[0] = 
1987
                    band_index_long[s->sample_rate_index][region_address1 + 1] >> 1;
1988
                l = region_address1 + region_address2 + 2;
1989
                /* should not overflow */
1990
                if (l > 22)
1991
                    l = 22;
1992
                g->region_size[1] = 
1993
                    band_index_long[s->sample_rate_index][l] >> 1;
1994
            }
1995
            /* convert region offsets to region sizes and truncate
1996
               size to big_values */
1997
            g->region_size[2] = (576 / 2);
1998
            j = 0;
1999
            for(i=0;i<3;i++) {
2000
                k = g->region_size[i];
2001
                if (k > g->big_values)
2002
                    k = g->big_values;
2003
                g->region_size[i] = k - j;
2004
                j = k;
2005
            }
2006

    
2007
            /* compute band indexes */
2008
            if (g->block_type == 2) {
2009
                if (g->switch_point) {
2010
                    /* if switched mode, we handle the 36 first samples as
2011
                       long blocks.  For 8000Hz, we handle the 48 first
2012
                       exponents as long blocks (XXX: check this!) */
2013
                    if (s->sample_rate_index <= 2)
2014
                        g->long_end = 8;
2015
                    else if (s->sample_rate_index != 8)
2016
                        g->long_end = 6;
2017
                    else
2018
                        g->long_end = 4; /* 8000 Hz */
2019
                    
2020
                    if (s->sample_rate_index != 8)
2021
                        g->short_start = 3;
2022
                    else
2023
                        g->short_start = 2; 
2024
                } else {
2025
                    g->long_end = 0;
2026
                    g->short_start = 0;
2027
                }
2028
            } else {
2029
                g->short_start = 13;
2030
                g->long_end = 22;
2031
            }
2032
            
2033
            g->preflag = 0;
2034
            if (!s->lsf)
2035
                g->preflag = get_bits(&s->gb, 1);
2036
            g->scalefac_scale = get_bits(&s->gb, 1);
2037
            g->count1table_select = get_bits(&s->gb, 1);
2038
            dprintf("block_type=%d switch_point=%d\n",
2039
                    g->block_type, g->switch_point);
2040
        }
2041
    }
2042

    
2043
    /* now we get bits from the main_data_begin offset */
2044
    dprintf("seekback: %d\n", main_data_begin);
2045
    seek_to_maindata(s, main_data_begin);
2046

    
2047
    for(gr=0;gr<nb_granules;gr++) {
2048
        for(ch=0;ch<s->nb_channels;ch++) {
2049
            g = &granules[ch][gr];
2050
            
2051
            bits_pos = get_bits_count(&s->gb);
2052
            
2053
            if (!s->lsf) {
2054
                UINT8 *sc;
2055
                int slen, slen1, slen2;
2056

    
2057
                /* MPEG1 scale factors */
2058
                slen1 = slen_table[0][g->scalefac_compress];
2059
                slen2 = slen_table[1][g->scalefac_compress];
2060
                dprintf("slen1=%d slen2=%d\n", slen1, slen2);
2061
                if (g->block_type == 2) {
2062
                    n = g->switch_point ? 17 : 18;
2063
                    j = 0;
2064
                    for(i=0;i<n;i++)
2065
                        g->scale_factors[j++] = get_bitsz(&s->gb, slen1);
2066
                    for(i=0;i<18;i++)
2067
                        g->scale_factors[j++] = get_bitsz(&s->gb, slen2);
2068
                    for(i=0;i<3;i++)
2069
                        g->scale_factors[j++] = 0;
2070
                } else {
2071
                    sc = granules[ch][0].scale_factors;
2072
                    j = 0;
2073
                    for(k=0;k<4;k++) {
2074
                        n = (k == 0 ? 6 : 5);
2075
                        if ((g->scfsi & (0x8 >> k)) == 0) {
2076
                            slen = (k < 2) ? slen1 : slen2;
2077
                            for(i=0;i<n;i++)
2078
                                g->scale_factors[j++] = get_bitsz(&s->gb, slen);
2079
                        } else {
2080
                            /* simply copy from last granule */
2081
                            for(i=0;i<n;i++) {
2082
                                g->scale_factors[j] = sc[j];
2083
                                j++;
2084
                            }
2085
                        }
2086
                    }
2087
                    g->scale_factors[j++] = 0;
2088
                }
2089
#ifdef DEBUG
2090
                {
2091
                    printf("scfsi=%x gr=%d ch=%d scale_factors:\n", 
2092
                           g->scfsi, gr, ch);
2093
                    for(i=0;i<j;i++)
2094
                        printf(" %d", g->scale_factors[i]);
2095
                    printf("\n");
2096
                }
2097
#endif
2098
            } else {
2099
                int tindex, tindex2, slen[4], sl, sf;
2100

    
2101
                /* LSF scale factors */
2102
                if (g->block_type == 2) {
2103
                    tindex = g->switch_point ? 2 : 1;
2104
                } else {
2105
                    tindex = 0;
2106
                }
2107
                sf = g->scalefac_compress;
2108
                if ((s->mode_ext & MODE_EXT_I_STEREO) && ch == 1) {
2109
                    /* intensity stereo case */
2110
                    sf >>= 1;
2111
                    if (sf < 180) {
2112
                        lsf_sf_expand(slen, sf, 6, 6, 0);
2113
                        tindex2 = 3;
2114
                    } else if (sf < 244) {
2115
                        lsf_sf_expand(slen, sf - 180, 4, 4, 0);
2116
                        tindex2 = 4;
2117
                    } else {
2118
                        lsf_sf_expand(slen, sf - 244, 3, 0, 0);
2119
                        tindex2 = 5;
2120
                    }
2121
                } else {
2122
                    /* normal case */
2123
                    if (sf < 400) {
2124
                        lsf_sf_expand(slen, sf, 5, 4, 4);
2125
                        tindex2 = 0;
2126
                    } else if (sf < 500) {
2127
                        lsf_sf_expand(slen, sf - 400, 5, 4, 0);
2128
                        tindex2 = 1;
2129
                    } else {
2130
                        lsf_sf_expand(slen, sf - 500, 3, 0, 0);
2131
                        tindex2 = 2;
2132
                        g->preflag = 1;
2133
                    }
2134
                }
2135

    
2136
                j = 0;
2137
                for(k=0;k<4;k++) {
2138
                    n = lsf_nsf_table[tindex2][tindex][k];
2139
                    sl = slen[k];
2140
                    for(i=0;i<n;i++)
2141
                        g->scale_factors[j++] = get_bitsz(&s->gb, sl);
2142
                }
2143
                /* XXX: should compute exact size */
2144
                for(;j<40;j++)
2145
                    g->scale_factors[j] = 0;
2146
#ifdef DEBUG
2147
                {
2148
                    printf("gr=%d ch=%d scale_factors:\n", 
2149
                           gr, ch);
2150
                    for(i=0;i<40;i++)
2151
                        printf(" %d", g->scale_factors[i]);
2152
                    printf("\n");
2153
                }
2154
#endif
2155
            }
2156

    
2157
            exponents_from_scale_factors(s, g, exponents);
2158

    
2159
            /* read Huffman coded residue */
2160
            if (huffman_decode(s, g, exponents,
2161
                               bits_pos + g->part2_3_length) < 0)
2162
                return -1;
2163
#if defined(DEBUG) && 0
2164
            sample_dump(3, g->sb_hybrid, 576);
2165
#endif
2166

    
2167
            /* skip extension bits */
2168
            bits_left = g->part2_3_length - (get_bits_count(&s->gb) - bits_pos);
2169
            if (bits_left < 0) {
2170
                dprintf("bits_left=%d\n", bits_left);
2171
                return -1;
2172
            }
2173
            while (bits_left >= 16) {
2174
                skip_bits(&s->gb, 16);
2175
                bits_left -= 16;
2176
            }
2177
            if (bits_left > 0)
2178
                skip_bits(&s->gb, bits_left);
2179
        } /* ch */
2180

    
2181
        if (s->nb_channels == 2)
2182
            compute_stereo(s, &granules[0][gr], &granules[1][gr]);
2183

    
2184
        for(ch=0;ch<s->nb_channels;ch++) {
2185
            g = &granules[ch][gr];
2186

    
2187
            reorder_block(s, g);
2188
#ifdef DEBUG
2189
            sample_dump(0, g->sb_hybrid, 576);
2190
#endif
2191
            compute_antialias(s, g);
2192
#ifdef DEBUG
2193
            sample_dump(1, g->sb_hybrid, 576);
2194
#endif
2195
            compute_imdct(s, g, &s->sb_samples[ch][18 * gr][0], s->mdct_buf[ch]); 
2196
#ifdef DEBUG
2197
            sample_dump(2, &s->sb_samples[ch][18 * gr][0], 576);
2198
#endif
2199
        }
2200
    } /* gr */
2201
    return nb_granules * 18;
2202
}
2203

    
2204
static int mp_decode_frame(MPADecodeContext *s, 
2205
                           short *samples)
2206
{
2207
    int i, nb_frames, ch;
2208
    short *samples_ptr;
2209

    
2210
    init_get_bits(&s->gb, s->inbuf + HEADER_SIZE, 
2211
                  s->inbuf_ptr - s->inbuf - HEADER_SIZE);
2212
    
2213
    /* skip error protection field */
2214
    if (s->error_protection)
2215
        get_bits(&s->gb, 16);
2216

    
2217
    dprintf("frame %d:\n", s->frame_count);
2218
    switch(s->layer) {
2219
    case 1:
2220
        nb_frames = mp_decode_layer1(s);
2221
        break;
2222
    case 2:
2223
        nb_frames = mp_decode_layer2(s);
2224
        break;
2225
    case 3:
2226
    default:
2227
        nb_frames = mp_decode_layer3(s);
2228
        break;
2229
    }
2230
#if defined(DEBUG)
2231
    for(i=0;i<nb_frames;i++) {
2232
        for(ch=0;ch<s->nb_channels;ch++) {
2233
            int j;
2234
            printf("%d-%d:", i, ch);
2235
            for(j=0;j<SBLIMIT;j++)
2236
                printf(" %0.6f", (double)s->sb_samples[ch][i][j] / FRAC_ONE);
2237
            printf("\n");
2238
        }
2239
    }
2240
#endif
2241
    /* apply the synthesis filter */
2242
    for(ch=0;ch<s->nb_channels;ch++) {
2243
        samples_ptr = samples + ch;
2244
        for(i=0;i<nb_frames;i++) {
2245
            synth_filter(s, ch, samples_ptr, s->nb_channels,
2246
                         s->sb_samples[ch][i]);
2247
            samples_ptr += 32 * s->nb_channels;
2248
        }
2249
    }
2250
#ifdef DEBUG
2251
    s->frame_count++;        
2252
#endif
2253
    return nb_frames * 32 * sizeof(short) * s->nb_channels;
2254
}
2255

    
2256
static int decode_frame(AVCodecContext * avctx,
2257
                        void *data, int *data_size,
2258
                        UINT8 * buf, int buf_size)
2259
{
2260
    MPADecodeContext *s = avctx->priv_data;
2261
    UINT32 header;
2262
    UINT8 *buf_ptr;
2263
    int len, out_size;
2264
    short *out_samples = data;
2265

    
2266
    *data_size = 0;
2267
    buf_ptr = buf;
2268
    while (buf_size > 0) {
2269
        len = s->inbuf_ptr - s->inbuf;
2270
        if (s->frame_size == 0) {
2271
            /* special case for next header for first frame in free
2272
               format case (XXX: find a simpler method) */
2273
            if (s->free_format_next_header != 0) {
2274
                s->inbuf[0] = s->free_format_next_header >> 24;
2275
                s->inbuf[1] = s->free_format_next_header >> 16;
2276
                s->inbuf[2] = s->free_format_next_header >> 8;
2277
                s->inbuf[3] = s->free_format_next_header;
2278
                s->inbuf_ptr = s->inbuf + 4;
2279
                s->free_format_next_header = 0;
2280
                goto got_header;
2281
            }
2282
            /* no header seen : find one. We need at least HEADER_SIZE
2283
               bytes to parse it */
2284
            len = HEADER_SIZE - len;
2285
            if (len > buf_size)
2286
                len = buf_size;
2287
            if (len > 0) {
2288
                memcpy(s->inbuf_ptr, buf_ptr, len);
2289
                buf_ptr += len;
2290
                buf_size -= len;
2291
                s->inbuf_ptr += len;
2292
            }
2293
            if ((s->inbuf_ptr - s->inbuf) >= HEADER_SIZE) {
2294
            got_header:
2295
                header = (s->inbuf[0] << 24) | (s->inbuf[1] << 16) |
2296
                    (s->inbuf[2] << 8) | s->inbuf[3];
2297

    
2298
                if (check_header(header) < 0) {
2299
                    /* no sync found : move by one byte (inefficient, but simple!) */
2300
                    memcpy(s->inbuf, s->inbuf + 1, s->inbuf_ptr - s->inbuf - 1);
2301
                    s->inbuf_ptr--;
2302
                    dprintf("skip %x\n", header);
2303
                    /* reset free format frame size to give a chance
2304
                       to get a new bitrate */
2305
                    s->free_format_frame_size = 0;
2306
                } else {
2307
                    if (decode_header(s, header) == 1) {
2308
                        /* free format: compute frame size */
2309
                        s->frame_size = -1;
2310
                        memcpy(s->inbuf, s->inbuf + 1, s->inbuf_ptr - s->inbuf - 1);
2311
                        s->inbuf_ptr--;
2312
                    } else {
2313
                        /* update codec info */
2314
                        avctx->sample_rate = s->sample_rate;
2315
                        avctx->channels = s->nb_channels;
2316
                        avctx->bit_rate = s->bit_rate;
2317
                        avctx->frame_size = s->frame_size;
2318
                    }
2319
                }
2320
            }
2321
        } else if (s->frame_size == -1) {
2322
            /* free format : find next sync to compute frame size */
2323
            len = MPA_MAX_CODED_FRAME_SIZE - len;
2324
            if (len > buf_size)
2325
                len = buf_size;
2326
            if (len == 0) {
2327
                /* frame too long: resync */
2328
                s->frame_size = 0;
2329
            } else {
2330
                UINT8 *p, *pend;
2331
                UINT32 header1;
2332
                int padding;
2333

    
2334
                memcpy(s->inbuf_ptr, buf_ptr, len);
2335
                /* check for header */
2336
                p = s->inbuf_ptr - 3;
2337
                pend = s->inbuf_ptr + len - 4;
2338
                while (p <= pend) {
2339
                    header = (p[0] << 24) | (p[1] << 16) |
2340
                        (p[2] << 8) | p[3];
2341
                    header1 = (s->inbuf[0] << 24) | (s->inbuf[1] << 16) |
2342
                        (s->inbuf[2] << 8) | s->inbuf[3];
2343
                    /* check with high probability that we have a
2344
                       valid header */
2345
                    if ((header & SAME_HEADER_MASK) ==
2346
                        (header1 & SAME_HEADER_MASK)) {
2347
                        /* header found: update pointers */
2348
                        len = (p + 4) - s->inbuf_ptr;
2349
                        buf_ptr += len;
2350
                        buf_size -= len;
2351
                        s->inbuf_ptr = p;
2352
                        /* compute frame size */
2353
                        s->free_format_next_header = header;
2354
                        s->free_format_frame_size = s->inbuf_ptr - s->inbuf;
2355
                        padding = (header1 >> 9) & 1;
2356
                        if (s->layer == 1)
2357
                            s->free_format_frame_size -= padding * 4;
2358
                        else
2359
                            s->free_format_frame_size -= padding;
2360
                        dprintf("free frame size=%d padding=%d\n", 
2361
                                s->free_format_frame_size, padding);
2362
                        decode_header(s, header1);
2363
                        goto next_data;
2364
                    }
2365
                    p++;
2366
                }
2367
                /* not found: simply increase pointers */
2368
                buf_ptr += len;
2369
                s->inbuf_ptr += len;
2370
                buf_size -= len;
2371
            }
2372
        } else if (len < s->frame_size) {
2373
            if (s->frame_size > MPA_MAX_CODED_FRAME_SIZE)
2374
                s->frame_size = MPA_MAX_CODED_FRAME_SIZE;
2375
            len = s->frame_size - len;
2376
            if (len > buf_size)
2377
                len = buf_size;
2378
            else if (len < 4)
2379
                len = buf_size > 4 ? 4 : buf_size;
2380
            memcpy(s->inbuf_ptr, buf_ptr, len);
2381
            buf_ptr += len;
2382
            s->inbuf_ptr += len;
2383
            buf_size -= len;
2384
        } else {
2385
            out_size = mp_decode_frame(s, out_samples);
2386
            s->inbuf_ptr = s->inbuf;
2387
            s->frame_size = 0;
2388
            *data_size = out_size;
2389
            break;
2390
        }
2391
    next_data:
2392
    }
2393
    return buf_ptr - buf;
2394
}
2395

    
2396
AVCodec mp2_decoder =
2397
{
2398
    "mp2",
2399
    CODEC_TYPE_AUDIO,
2400
    CODEC_ID_MP2,
2401
    sizeof(MPADecodeContext),
2402
    decode_init,
2403
    NULL,
2404
    NULL,
2405
    decode_frame,
2406
};
2407

    
2408
AVCodec mp3_decoder =
2409
{
2410
    "mp3",
2411
    CODEC_TYPE_AUDIO,
2412
    CODEC_ID_MP3LAME,
2413
    sizeof(MPADecodeContext),
2414
    decode_init,
2415
    NULL,
2416
    NULL,
2417
    decode_frame,
2418
};