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1 /*
2  * MPEG Audio decoder
3  * Copyright (c) 2001, 2002 Fabrice Bellard
4  *
5  * This file is part of FFmpeg.
6  *
7  * FFmpeg is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU Lesser General Public
9  * License as published by the Free Software Foundation; either
10  * version 2.1 of the License, or (at your option) any later version.
11  *
12  * FFmpeg is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
15  * Lesser General Public License for more details.
16  *
17  * You should have received a copy of the GNU Lesser General Public
18  * License along with FFmpeg; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
22 /**
23  * @file
24  * MPEG Audio decoder
25  */
26 
27 #include "config_components.h"
28 
29 #include "libavutil/attributes.h"
30 #include "libavutil/avassert.h"
31 #include "libavutil/channel_layout.h"
32 #include "libavutil/crc.h"
33 #include "libavutil/float_dsp.h"
34 #include "libavutil/libm.h"
35 #include "libavutil/mem_internal.h"
36 #include "libavutil/thread.h"
37 
38 #include "avcodec.h"
39 #include "get_bits.h"
40 #include "internal.h"
41 #include "mathops.h"
42 #include "mpegaudiodsp.h"
43 
44 /*
45  * TODO:
46  *  - test lsf / mpeg25 extensively.
47  */
48 
49 #include "mpegaudio.h"
50 #include "mpegaudiodecheader.h"
51 
52 #define BACKSTEP_SIZE 512
53 #define EXTRABYTES 24
54 #define LAST_BUF_SIZE 2 * BACKSTEP_SIZE + EXTRABYTES
55 
56 /* layer 3 "granule" */
57 typedef struct GranuleDef {
58     uint8_t scfsi;
59     int part2_3_length;
60     int big_values;
61     int global_gain;
62     int scalefac_compress;
63     uint8_t block_type;
64     uint8_t switch_point;
65     int table_select[3];
66     int subblock_gain[3];
67     uint8_t scalefac_scale;
68     uint8_t count1table_select;
69     int region_size[3]; /* number of huffman codes in each region */
70     int preflag;
71     int short_start, long_end; /* long/short band indexes */
72     uint8_t scale_factors[40];
73     DECLARE_ALIGNED(16, INTFLOAT, sb_hybrid)[SBLIMIT * 18]; /* 576 samples */
74 } GranuleDef;
75 
76 typedef struct MPADecodeContext {
77     MPA_DECODE_HEADER
78     uint8_t last_buf[LAST_BUF_SIZE];
79     int last_buf_size;
80     int extrasize;
81     /* next header (used in free format parsing) */
82     uint32_t free_format_next_header;
83     GetBitContext gb;
84     GetBitContext in_gb;
85     DECLARE_ALIGNED(32, MPA_INT, synth_buf)[MPA_MAX_CHANNELS][512 * 2];
86     int synth_buf_offset[MPA_MAX_CHANNELS];
87     DECLARE_ALIGNED(32, INTFLOAT, sb_samples)[MPA_MAX_CHANNELS][36][SBLIMIT];
88     INTFLOAT mdct_buf[MPA_MAX_CHANNELS][SBLIMIT * 18]; /* previous samples, for layer 3 MDCT */
89     GranuleDef granules[2][2]; /* Used in Layer 3 */
90     int adu_mode; ///< 0 for standard mp3, 1 for adu formatted mp3
91     int dither_state;
92     int err_recognition;
93     AVCodecContext* avctx;
94     MPADSPContext mpadsp;
95     void (*butterflies_float)(float *av_restrict v1, float *av_restrict v2, int len);
96     AVFrame *frame;
97     uint32_t crc;
98 } MPADecodeContext;
99 
100 #define HEADER_SIZE 4
101 
102 #include "mpegaudiodata.h"
103 
104 #include "mpegaudio_tablegen.h"
105 /* intensity stereo coef table */
106 static INTFLOAT is_table_lsf[2][2][16];
107 
108 /* [i][j]:  2^(-j/3) * FRAC_ONE * 2^(i+2) / (2^(i+2) - 1) */
109 static int32_t scale_factor_mult[15][3];
110 /* mult table for layer 2 group quantization */
111 
112 #define SCALE_GEN(v) \
113 { FIXR_OLD(1.0 * (v)), FIXR_OLD(0.7937005259 * (v)), FIXR_OLD(0.6299605249 * (v)) }
114 
115 static const int32_t scale_factor_mult2[3][3] = {
116     SCALE_GEN(4.0 / 3.0), /* 3 steps */
117     SCALE_GEN(4.0 / 5.0), /* 5 steps */
118     SCALE_GEN(4.0 / 9.0), /* 9 steps */
119 };
120 
121 /**
122  * Convert region offsets to region sizes and truncate
123  * size to big_values.
124  */
region_offset2size(GranuleDef * g)125 static void region_offset2size(GranuleDef *g)
126 {
127     int i, k, j = 0;
128     g->region_size[2] = 576 / 2;
129     for (i = 0; i < 3; i++) {
130         k = FFMIN(g->region_size[i], g->big_values);
131         g->region_size[i] = k - j;
132         j = k;
133     }
134 }
135 
init_short_region(MPADecodeContext * s,GranuleDef * g)136 static void init_short_region(MPADecodeContext *s, GranuleDef *g)
137 {
138     if (g->block_type == 2) {
139         if (s->sample_rate_index != 8)
140             g->region_size[0] = (36 / 2);
141         else
142             g->region_size[0] = (72 / 2);
143     } else {
144         if (s->sample_rate_index <= 2)
145             g->region_size[0] = (36 / 2);
146         else if (s->sample_rate_index != 8)
147             g->region_size[0] = (54 / 2);
148         else
149             g->region_size[0] = (108 / 2);
150     }
151     g->region_size[1] = (576 / 2);
152 }
153 
init_long_region(MPADecodeContext * s,GranuleDef * g,int ra1,int ra2)154 static void init_long_region(MPADecodeContext *s, GranuleDef *g,
155                              int ra1, int ra2)
156 {
157     int l;
158     g->region_size[0] = ff_band_index_long[s->sample_rate_index][ra1 + 1];
159     /* should not overflow */
160     l = FFMIN(ra1 + ra2 + 2, 22);
161     g->region_size[1] = ff_band_index_long[s->sample_rate_index][      l];
162 }
163 
compute_band_indexes(MPADecodeContext * s,GranuleDef * g)164 static void compute_band_indexes(MPADecodeContext *s, GranuleDef *g)
165 {
166     if (g->block_type == 2) {
167         if (g->switch_point) {
168             if(s->sample_rate_index == 8)
169                 avpriv_request_sample(s->avctx, "switch point in 8khz");
170             /* if switched mode, we handle the 36 first samples as
171                 long blocks.  For 8000Hz, we handle the 72 first
172                 exponents as long blocks */
173             if (s->sample_rate_index <= 2)
174                 g->long_end = 8;
175             else
176                 g->long_end = 6;
177 
178             g->short_start = 3;
179         } else {
180             g->long_end    = 0;
181             g->short_start = 0;
182         }
183     } else {
184         g->short_start = 13;
185         g->long_end    = 22;
186     }
187 }
188 
189 /* layer 1 unscaling */
190 /* n = number of bits of the mantissa minus 1 */
l1_unscale(int n,int mant,int scale_factor)191 static inline int l1_unscale(int n, int mant, int scale_factor)
192 {
193     int shift, mod;
194     int64_t val;
195 
196     shift   = ff_scale_factor_modshift[scale_factor];
197     mod     = shift & 3;
198     shift >>= 2;
199     val     = MUL64((int)(mant + (-1U << n) + 1), scale_factor_mult[n-1][mod]);
200     shift  += n;
201     /* NOTE: at this point, 1 <= shift >= 21 + 15 */
202     return (int)((val + (1LL << (shift - 1))) >> shift);
203 }
204 
l2_unscale_group(int steps,int mant,int scale_factor)205 static inline int l2_unscale_group(int steps, int mant, int scale_factor)
206 {
207     int shift, mod, val;
208 
209     shift   = ff_scale_factor_modshift[scale_factor];
210     mod     = shift & 3;
211     shift >>= 2;
212 
213     val = (mant - (steps >> 1)) * scale_factor_mult2[steps >> 2][mod];
214     /* NOTE: at this point, 0 <= shift <= 21 */
215     if (shift > 0)
216         val = (val + (1 << (shift - 1))) >> shift;
217     return val;
218 }
219 
220 /* compute value^(4/3) * 2^(exponent/4). It normalized to FRAC_BITS */
l3_unscale(int value,int exponent)221 static inline int l3_unscale(int value, int exponent)
222 {
223     unsigned int m;
224     int e;
225 
226     e  = ff_table_4_3_exp  [4 * value + (exponent & 3)];
227     m  = ff_table_4_3_value[4 * value + (exponent & 3)];
228     e -= exponent >> 2;
229 #ifdef DEBUG
230     if(e < 1)
231         av_log(NULL, AV_LOG_WARNING, "l3_unscale: e is %d\n", e);
232 #endif
233     if (e > (SUINT)31)
234         return 0;
235     m = (m + ((1U << e) >> 1)) >> e;
236 
237     return m;
238 }
239 
decode_init_static(void)240 static av_cold void decode_init_static(void)
241 {
242     int i, j;
243 
244     /* scale factor multiply for layer 1 */
245     for (i = 0; i < 15; i++) {
246         int n, norm;
247         n = i + 2;
248         norm = ((INT64_C(1) << n) * FRAC_ONE) / ((1 << n) - 1);
249         scale_factor_mult[i][0] = MULLx(norm, FIXR(1.0          * 2.0), FRAC_BITS);
250         scale_factor_mult[i][1] = MULLx(norm, FIXR(0.7937005259 * 2.0), FRAC_BITS);
251         scale_factor_mult[i][2] = MULLx(norm, FIXR(0.6299605249 * 2.0), FRAC_BITS);
252         ff_dlog(NULL, "%d: norm=%x s=%"PRIx32" %"PRIx32" %"PRIx32"\n", i,
253                 (unsigned)norm,
254                 scale_factor_mult[i][0],
255                 scale_factor_mult[i][1],
256                 scale_factor_mult[i][2]);
257     }
258 
259     /* compute n ^ (4/3) and store it in mantissa/exp format */
260 
261     mpegaudio_tableinit();
262 
263     for (i = 0; i < 16; i++) {
264         double f;
265         int e, k;
266 
267         for (j = 0; j < 2; j++) {
268             e = -(j + 1) * ((i + 1) >> 1);
269             f = exp2(e / 4.0);
270             k = i & 1;
271             is_table_lsf[j][k ^ 1][i] = FIXR(f);
272             is_table_lsf[j][k    ][i] = FIXR(1.0);
273             ff_dlog(NULL, "is_table_lsf %d %d: %f %f\n",
274                     i, j, (float) is_table_lsf[j][0][i],
275                     (float) is_table_lsf[j][1][i]);
276         }
277     }
278     RENAME(ff_mpa_synth_init)();
279     ff_mpegaudiodec_common_init_static();
280 }
281 
decode_init(AVCodecContext * avctx)282 static av_cold int decode_init(AVCodecContext * avctx)
283 {
284     static AVOnce init_static_once = AV_ONCE_INIT;
285     MPADecodeContext *s = avctx->priv_data;
286 
287     s->avctx = avctx;
288 
289 #if USE_FLOATS
290     {
291         AVFloatDSPContext *fdsp;
292         fdsp = avpriv_float_dsp_alloc(avctx->flags & AV_CODEC_FLAG_BITEXACT);
293         if (!fdsp)
294             return AVERROR(ENOMEM);
295         s->butterflies_float = fdsp->butterflies_float;
296         av_free(fdsp);
297     }
298 #endif
299 
300     ff_mpadsp_init(&s->mpadsp);
301 
302     if (avctx->request_sample_fmt == OUT_FMT &&
303         avctx->codec_id != AV_CODEC_ID_MP3ON4)
304         avctx->sample_fmt = OUT_FMT;
305     else
306         avctx->sample_fmt = OUT_FMT_P;
307     s->err_recognition = avctx->err_recognition;
308 
309     if (avctx->codec_id == AV_CODEC_ID_MP3ADU)
310         s->adu_mode = 1;
311 
312     ff_thread_once(&init_static_once, decode_init_static);
313 
314     return 0;
315 }
316 
317 #define C3 FIXHR(0.86602540378443864676/2)
318 #define C4 FIXHR(0.70710678118654752439/2) //0.5 / cos(pi*(9)/36)
319 #define C5 FIXHR(0.51763809020504152469/2) //0.5 / cos(pi*(5)/36)
320 #define C6 FIXHR(1.93185165257813657349/4) //0.5 / cos(pi*(15)/36)
321 
322 /* 12 points IMDCT. We compute it "by hand" by factorizing obvious
323    cases. */
imdct12(INTFLOAT * out,SUINTFLOAT * in)324 static void imdct12(INTFLOAT *out, SUINTFLOAT *in)
325 {
326     SUINTFLOAT in0, in1, in2, in3, in4, in5, t1, t2;
327 
328     in0  = in[0*3];
329     in1  = in[1*3] + in[0*3];
330     in2  = in[2*3] + in[1*3];
331     in3  = in[3*3] + in[2*3];
332     in4  = in[4*3] + in[3*3];
333     in5  = in[5*3] + in[4*3];
334     in5 += in3;
335     in3 += in1;
336 
337     in2  = MULH3(in2, C3, 2);
338     in3  = MULH3(in3, C3, 4);
339 
340     t1   = in0 - in4;
341     t2   = MULH3(in1 - in5, C4, 2);
342 
343     out[ 7] =
344     out[10] = t1 + t2;
345     out[ 1] =
346     out[ 4] = t1 - t2;
347 
348     in0    += SHR(in4, 1);
349     in4     = in0 + in2;
350     in5    += 2*in1;
351     in1     = MULH3(in5 + in3, C5, 1);
352     out[ 8] =
353     out[ 9] = in4 + in1;
354     out[ 2] =
355     out[ 3] = in4 - in1;
356 
357     in0    -= in2;
358     in5     = MULH3(in5 - in3, C6, 2);
359     out[ 0] =
360     out[ 5] = in0 - in5;
361     out[ 6] =
362     out[11] = in0 + in5;
363 }
364 
handle_crc(MPADecodeContext * s,int sec_len)365 static int handle_crc(MPADecodeContext *s, int sec_len)
366 {
367     if (s->error_protection && (s->err_recognition & AV_EF_CRCCHECK)) {
368         const uint8_t *buf = s->gb.buffer - HEADER_SIZE;
369         int sec_byte_len  = sec_len >> 3;
370         int sec_rem_bits  = sec_len & 7;
371         const AVCRC *crc_tab = av_crc_get_table(AV_CRC_16_ANSI);
372         uint8_t tmp_buf[4];
373         uint32_t crc_val = av_crc(crc_tab, UINT16_MAX, &buf[2], 2);
374         crc_val = av_crc(crc_tab, crc_val, &buf[6], sec_byte_len);
375 
376         AV_WB32(tmp_buf,
377                 ((buf[6 + sec_byte_len] & (0xFF00U >> sec_rem_bits)) << 24) +
378                 ((s->crc << 16) >> sec_rem_bits));
379 
380         crc_val = av_crc(crc_tab, crc_val, tmp_buf, 3);
381 
382         if (crc_val) {
383             av_log(s->avctx, AV_LOG_ERROR, "CRC mismatch %X!\n", crc_val);
384             if (s->err_recognition & AV_EF_EXPLODE)
385                 return AVERROR_INVALIDDATA;
386         }
387     }
388     return 0;
389 }
390 
391 /* return the number of decoded frames */
mp_decode_layer1(MPADecodeContext * s)392 static int mp_decode_layer1(MPADecodeContext *s)
393 {
394     int bound, i, v, n, ch, j, mant;
395     uint8_t allocation[MPA_MAX_CHANNELS][SBLIMIT];
396     uint8_t scale_factors[MPA_MAX_CHANNELS][SBLIMIT];
397     int ret;
398 
399     ret = handle_crc(s, (s->nb_channels == 1) ? 8*16  : 8*32);
400     if (ret < 0)
401         return ret;
402 
403     if (s->mode == MPA_JSTEREO)
404         bound = (s->mode_ext + 1) * 4;
405     else
406         bound = SBLIMIT;
407 
408     /* allocation bits */
409     for (i = 0; i < bound; i++) {
410         for (ch = 0; ch < s->nb_channels; ch++) {
411             allocation[ch][i] = get_bits(&s->gb, 4);
412         }
413     }
414     for (i = bound; i < SBLIMIT; i++)
415         allocation[0][i] = get_bits(&s->gb, 4);
416 
417     /* scale factors */
418     for (i = 0; i < bound; i++) {
419         for (ch = 0; ch < s->nb_channels; ch++) {
420             if (allocation[ch][i])
421                 scale_factors[ch][i] = get_bits(&s->gb, 6);
422         }
423     }
424     for (i = bound; i < SBLIMIT; i++) {
425         if (allocation[0][i]) {
426             scale_factors[0][i] = get_bits(&s->gb, 6);
427             scale_factors[1][i] = get_bits(&s->gb, 6);
428         }
429     }
430 
431     /* compute samples */
432     for (j = 0; j < 12; j++) {
433         for (i = 0; i < bound; i++) {
434             for (ch = 0; ch < s->nb_channels; ch++) {
435                 n = allocation[ch][i];
436                 if (n) {
437                     mant = get_bits(&s->gb, n + 1);
438                     v = l1_unscale(n, mant, scale_factors[ch][i]);
439                 } else {
440                     v = 0;
441                 }
442                 s->sb_samples[ch][j][i] = v;
443             }
444         }
445         for (i = bound; i < SBLIMIT; i++) {
446             n = allocation[0][i];
447             if (n) {
448                 mant = get_bits(&s->gb, n + 1);
449                 v = l1_unscale(n, mant, scale_factors[0][i]);
450                 s->sb_samples[0][j][i] = v;
451                 v = l1_unscale(n, mant, scale_factors[1][i]);
452                 s->sb_samples[1][j][i] = v;
453             } else {
454                 s->sb_samples[0][j][i] = 0;
455                 s->sb_samples[1][j][i] = 0;
456             }
457         }
458     }
459     return 12;
460 }
461 
mp_decode_layer2(MPADecodeContext * s)462 static int mp_decode_layer2(MPADecodeContext *s)
463 {
464     int sblimit; /* number of used subbands */
465     const unsigned char *alloc_table;
466     int table, bit_alloc_bits, i, j, ch, bound, v;
467     unsigned char bit_alloc[MPA_MAX_CHANNELS][SBLIMIT];
468     unsigned char scale_code[MPA_MAX_CHANNELS][SBLIMIT];
469     unsigned char scale_factors[MPA_MAX_CHANNELS][SBLIMIT][3], *sf;
470     int scale, qindex, bits, steps, k, l, m, b;
471     int ret;
472 
473     /* select decoding table */
474     table = ff_mpa_l2_select_table(s->bit_rate / 1000, s->nb_channels,
475                                    s->sample_rate, s->lsf);
476     sblimit     = ff_mpa_sblimit_table[table];
477     alloc_table = ff_mpa_alloc_tables[table];
478 
479     if (s->mode == MPA_JSTEREO)
480         bound = (s->mode_ext + 1) * 4;
481     else
482         bound = sblimit;
483 
484     ff_dlog(s->avctx, "bound=%d sblimit=%d\n", bound, sblimit);
485 
486     /* sanity check */
487     if (bound > sblimit)
488         bound = sblimit;
489 
490     /* parse bit allocation */
491     j = 0;
492     for (i = 0; i < bound; i++) {
493         bit_alloc_bits = alloc_table[j];
494         for (ch = 0; ch < s->nb_channels; ch++)
495             bit_alloc[ch][i] = get_bits(&s->gb, bit_alloc_bits);
496         j += 1 << bit_alloc_bits;
497     }
498     for (i = bound; i < sblimit; i++) {
499         bit_alloc_bits = alloc_table[j];
500         v = get_bits(&s->gb, bit_alloc_bits);
501         bit_alloc[0][i] = v;
502         bit_alloc[1][i] = v;
503         j += 1 << bit_alloc_bits;
504     }
505 
506     /* scale codes */
507     for (i = 0; i < sblimit; i++) {
508         for (ch = 0; ch < s->nb_channels; ch++) {
509             if (bit_alloc[ch][i])
510                 scale_code[ch][i] = get_bits(&s->gb, 2);
511         }
512     }
513 
514     ret = handle_crc(s, get_bits_count(&s->gb) - 16);
515     if (ret < 0)
516         return ret;
517 
518     /* scale factors */
519     for (i = 0; i < sblimit; i++) {
520         for (ch = 0; ch < s->nb_channels; ch++) {
521             if (bit_alloc[ch][i]) {
522                 sf = scale_factors[ch][i];
523                 switch (scale_code[ch][i]) {
524                 default:
525                 case 0:
526                     sf[0] = get_bits(&s->gb, 6);
527                     sf[1] = get_bits(&s->gb, 6);
528                     sf[2] = get_bits(&s->gb, 6);
529                     break;
530                 case 2:
531                     sf[0] = get_bits(&s->gb, 6);
532                     sf[1] = sf[0];
533                     sf[2] = sf[0];
534                     break;
535                 case 1:
536                     sf[0] = get_bits(&s->gb, 6);
537                     sf[2] = get_bits(&s->gb, 6);
538                     sf[1] = sf[0];
539                     break;
540                 case 3:
541                     sf[0] = get_bits(&s->gb, 6);
542                     sf[2] = get_bits(&s->gb, 6);
543                     sf[1] = sf[2];
544                     break;
545                 }
546             }
547         }
548     }
549 
550     /* samples */
551     for (k = 0; k < 3; k++) {
552         for (l = 0; l < 12; l += 3) {
553             j = 0;
554             for (i = 0; i < bound; i++) {
555                 bit_alloc_bits = alloc_table[j];
556                 for (ch = 0; ch < s->nb_channels; ch++) {
557                     b = bit_alloc[ch][i];
558                     if (b) {
559                         scale = scale_factors[ch][i][k];
560                         qindex = alloc_table[j+b];
561                         bits = ff_mpa_quant_bits[qindex];
562                         if (bits < 0) {
563                             int v2;
564                             /* 3 values at the same time */
565                             v = get_bits(&s->gb, -bits);
566                             v2 = ff_division_tabs[qindex][v];
567                             steps  = ff_mpa_quant_steps[qindex];
568 
569                             s->sb_samples[ch][k * 12 + l + 0][i] =
570                                 l2_unscale_group(steps,  v2       & 15, scale);
571                             s->sb_samples[ch][k * 12 + l + 1][i] =
572                                 l2_unscale_group(steps, (v2 >> 4) & 15, scale);
573                             s->sb_samples[ch][k * 12 + l + 2][i] =
574                                 l2_unscale_group(steps,  v2 >> 8      , scale);
575                         } else {
576                             for (m = 0; m < 3; m++) {
577                                 v = get_bits(&s->gb, bits);
578                                 v = l1_unscale(bits - 1, v, scale);
579                                 s->sb_samples[ch][k * 12 + l + m][i] = v;
580                             }
581                         }
582                     } else {
583                         s->sb_samples[ch][k * 12 + l + 0][i] = 0;
584                         s->sb_samples[ch][k * 12 + l + 1][i] = 0;
585                         s->sb_samples[ch][k * 12 + l + 2][i] = 0;
586                     }
587                 }
588                 /* next subband in alloc table */
589                 j += 1 << bit_alloc_bits;
590             }
591             /* XXX: find a way to avoid this duplication of code */
592             for (i = bound; i < sblimit; i++) {
593                 bit_alloc_bits = alloc_table[j];
594                 b = bit_alloc[0][i];
595                 if (b) {
596                     int mant, scale0, scale1;
597                     scale0 = scale_factors[0][i][k];
598                     scale1 = scale_factors[1][i][k];
599                     qindex = alloc_table[j + b];
600                     bits = ff_mpa_quant_bits[qindex];
601                     if (bits < 0) {
602                         /* 3 values at the same time */
603                         v = get_bits(&s->gb, -bits);
604                         steps = ff_mpa_quant_steps[qindex];
605                         mant = v % steps;
606                         v = v / steps;
607                         s->sb_samples[0][k * 12 + l + 0][i] =
608                             l2_unscale_group(steps, mant, scale0);
609                         s->sb_samples[1][k * 12 + l + 0][i] =
610                             l2_unscale_group(steps, mant, scale1);
611                         mant = v % steps;
612                         v = v / steps;
613                         s->sb_samples[0][k * 12 + l + 1][i] =
614                             l2_unscale_group(steps, mant, scale0);
615                         s->sb_samples[1][k * 12 + l + 1][i] =
616                             l2_unscale_group(steps, mant, scale1);
617                         s->sb_samples[0][k * 12 + l + 2][i] =
618                             l2_unscale_group(steps, v, scale0);
619                         s->sb_samples[1][k * 12 + l + 2][i] =
620                             l2_unscale_group(steps, v, scale1);
621                     } else {
622                         for (m = 0; m < 3; m++) {
623                             mant = get_bits(&s->gb, bits);
624                             s->sb_samples[0][k * 12 + l + m][i] =
625                                 l1_unscale(bits - 1, mant, scale0);
626                             s->sb_samples[1][k * 12 + l + m][i] =
627                                 l1_unscale(bits - 1, mant, scale1);
628                         }
629                     }
630                 } else {
631                     s->sb_samples[0][k * 12 + l + 0][i] = 0;
632                     s->sb_samples[0][k * 12 + l + 1][i] = 0;
633                     s->sb_samples[0][k * 12 + l + 2][i] = 0;
634                     s->sb_samples[1][k * 12 + l + 0][i] = 0;
635                     s->sb_samples[1][k * 12 + l + 1][i] = 0;
636                     s->sb_samples[1][k * 12 + l + 2][i] = 0;
637                 }
638                 /* next subband in alloc table */
639                 j += 1 << bit_alloc_bits;
640             }
641             /* fill remaining samples to zero */
642             for (i = sblimit; i < SBLIMIT; i++) {
643                 for (ch = 0; ch < s->nb_channels; ch++) {
644                     s->sb_samples[ch][k * 12 + l + 0][i] = 0;
645                     s->sb_samples[ch][k * 12 + l + 1][i] = 0;
646                     s->sb_samples[ch][k * 12 + l + 2][i] = 0;
647                 }
648             }
649         }
650     }
651     return 3 * 12;
652 }
653 
654 #define SPLIT(dst,sf,n)             \
655     if (n == 3) {                   \
656         int m = (sf * 171) >> 9;    \
657         dst   = sf - 3 * m;         \
658         sf    = m;                  \
659     } else if (n == 4) {            \
660         dst  = sf & 3;              \
661         sf >>= 2;                   \
662     } else if (n == 5) {            \
663         int m = (sf * 205) >> 10;   \
664         dst   = sf - 5 * m;         \
665         sf    = m;                  \
666     } else if (n == 6) {            \
667         int m = (sf * 171) >> 10;   \
668         dst   = sf - 6 * m;         \
669         sf    = m;                  \
670     } else {                        \
671         dst = 0;                    \
672     }
673 
lsf_sf_expand(int * slen,int sf,int n1,int n2,int n3)674 static av_always_inline void lsf_sf_expand(int *slen, int sf, int n1, int n2,
675                                            int n3)
676 {
677     SPLIT(slen[3], sf, n3)
678     SPLIT(slen[2], sf, n2)
679     SPLIT(slen[1], sf, n1)
680     slen[0] = sf;
681 }
682 
exponents_from_scale_factors(MPADecodeContext * s,GranuleDef * g,int16_t * exponents)683 static void exponents_from_scale_factors(MPADecodeContext *s, GranuleDef *g,
684                                          int16_t *exponents)
685 {
686     const uint8_t *bstab, *pretab;
687     int len, i, j, k, l, v0, shift, gain, gains[3];
688     int16_t *exp_ptr;
689 
690     exp_ptr = exponents;
691     gain    = g->global_gain - 210;
692     shift   = g->scalefac_scale + 1;
693 
694     bstab  = ff_band_size_long[s->sample_rate_index];
695     pretab = ff_mpa_pretab[g->preflag];
696     for (i = 0; i < g->long_end; i++) {
697         v0 = gain - ((g->scale_factors[i] + pretab[i]) << shift) + 400;
698         len = bstab[i];
699         for (j = len; j > 0; j--)
700             *exp_ptr++ = v0;
701     }
702 
703     if (g->short_start < 13) {
704         bstab    = ff_band_size_short[s->sample_rate_index];
705         gains[0] = gain - (g->subblock_gain[0] << 3);
706         gains[1] = gain - (g->subblock_gain[1] << 3);
707         gains[2] = gain - (g->subblock_gain[2] << 3);
708         k        = g->long_end;
709         for (i = g->short_start; i < 13; i++) {
710             len = bstab[i];
711             for (l = 0; l < 3; l++) {
712                 v0 = gains[l] - (g->scale_factors[k++] << shift) + 400;
713                 for (j = len; j > 0; j--)
714                     *exp_ptr++ = v0;
715             }
716         }
717     }
718 }
719 
switch_buffer(MPADecodeContext * s,int * pos,int * end_pos,int * end_pos2)720 static void switch_buffer(MPADecodeContext *s, int *pos, int *end_pos,
721                           int *end_pos2)
722 {
723     if (s->in_gb.buffer && *pos >= s->gb.size_in_bits - s->extrasize * 8) {
724         s->gb           = s->in_gb;
725         s->in_gb.buffer = NULL;
726         s->extrasize    = 0;
727         av_assert2((get_bits_count(&s->gb) & 7) == 0);
728         skip_bits_long(&s->gb, *pos - *end_pos);
729         *end_pos2 =
730         *end_pos  = *end_pos2 + get_bits_count(&s->gb) - *pos;
731         *pos      = get_bits_count(&s->gb);
732     }
733 }
734 
735 /* Following is an optimized code for
736             INTFLOAT v = *src
737             if(get_bits1(&s->gb))
738                 v = -v;
739             *dst = v;
740 */
741 #if USE_FLOATS
742 #define READ_FLIP_SIGN(dst,src)                     \
743     v = AV_RN32A(src) ^ (get_bits1(&s->gb) << 31);  \
744     AV_WN32A(dst, v);
745 #else
746 #define READ_FLIP_SIGN(dst,src)     \
747     v      = -get_bits1(&s->gb);    \
748     *(dst) = (*(src) ^ v) - v;
749 #endif
750 
huffman_decode(MPADecodeContext * s,GranuleDef * g,int16_t * exponents,int end_pos2)751 static int huffman_decode(MPADecodeContext *s, GranuleDef *g,
752                           int16_t *exponents, int end_pos2)
753 {
754     int s_index;
755     int i;
756     int last_pos, bits_left;
757     VLC *vlc;
758     int end_pos = FFMIN(end_pos2, s->gb.size_in_bits - s->extrasize * 8);
759 
760     /* low frequencies (called big values) */
761     s_index = 0;
762     for (i = 0; i < 3; i++) {
763         int j, k, l, linbits;
764         j = g->region_size[i];
765         if (j == 0)
766             continue;
767         /* select vlc table */
768         k       = g->table_select[i];
769         l       = ff_mpa_huff_data[k][0];
770         linbits = ff_mpa_huff_data[k][1];
771         vlc     = &ff_huff_vlc[l];
772 
773         if (!l) {
774             memset(&g->sb_hybrid[s_index], 0, sizeof(*g->sb_hybrid) * 2 * j);
775             s_index += 2 * j;
776             continue;
777         }
778 
779         /* read huffcode and compute each couple */
780         for (; j > 0; j--) {
781             int exponent, x, y;
782             int v;
783             int pos = get_bits_count(&s->gb);
784 
785             if (pos >= end_pos){
786                 switch_buffer(s, &pos, &end_pos, &end_pos2);
787                 if (pos >= end_pos)
788                     break;
789             }
790             y = get_vlc2(&s->gb, vlc->table, 7, 3);
791 
792             if (!y) {
793                 g->sb_hybrid[s_index    ] =
794                 g->sb_hybrid[s_index + 1] = 0;
795                 s_index += 2;
796                 continue;
797             }
798 
799             exponent= exponents[s_index];
800 
801             ff_dlog(s->avctx, "region=%d n=%d y=%d exp=%d\n",
802                     i, g->region_size[i] - j, y, exponent);
803             if (y & 16) {
804                 x = y >> 5;
805                 y = y & 0x0f;
806                 if (x < 15) {
807                     READ_FLIP_SIGN(g->sb_hybrid + s_index, RENAME(expval_table)[exponent] + x)
808                 } else {
809                     x += get_bitsz(&s->gb, linbits);
810                     v  = l3_unscale(x, exponent);
811                     if (get_bits1(&s->gb))
812                         v = -v;
813                     g->sb_hybrid[s_index] = v;
814                 }
815                 if (y < 15) {
816                     READ_FLIP_SIGN(g->sb_hybrid + s_index + 1, RENAME(expval_table)[exponent] + y)
817                 } else {
818                     y += get_bitsz(&s->gb, linbits);
819                     v  = l3_unscale(y, exponent);
820                     if (get_bits1(&s->gb))
821                         v = -v;
822                     g->sb_hybrid[s_index + 1] = v;
823                 }
824             } else {
825                 x = y >> 5;
826                 y = y & 0x0f;
827                 x += y;
828                 if (x < 15) {
829                     READ_FLIP_SIGN(g->sb_hybrid + s_index + !!y, RENAME(expval_table)[exponent] + x)
830                 } else {
831                     x += get_bitsz(&s->gb, linbits);
832                     v  = l3_unscale(x, exponent);
833                     if (get_bits1(&s->gb))
834                         v = -v;
835                     g->sb_hybrid[s_index+!!y] = v;
836                 }
837                 g->sb_hybrid[s_index + !y] = 0;
838             }
839             s_index += 2;
840         }
841     }
842 
843     /* high frequencies */
844     vlc = &ff_huff_quad_vlc[g->count1table_select];
845     last_pos = 0;
846     while (s_index <= 572) {
847         int pos, code;
848         pos = get_bits_count(&s->gb);
849         if (pos >= end_pos) {
850             if (pos > end_pos2 && last_pos) {
851                 /* some encoders generate an incorrect size for this
852                    part. We must go back into the data */
853                 s_index -= 4;
854                 skip_bits_long(&s->gb, last_pos - pos);
855                 av_log(s->avctx, AV_LOG_INFO, "overread, skip %d enddists: %d %d\n", last_pos - pos, end_pos-pos, end_pos2-pos);
856                 if(s->err_recognition & (AV_EF_BITSTREAM|AV_EF_COMPLIANT))
857                     s_index=0;
858                 break;
859             }
860             switch_buffer(s, &pos, &end_pos, &end_pos2);
861             if (pos >= end_pos)
862                 break;
863         }
864         last_pos = pos;
865 
866         code = get_vlc2(&s->gb, vlc->table, vlc->bits, 1);
867         ff_dlog(s->avctx, "t=%d code=%d\n", g->count1table_select, code);
868         g->sb_hybrid[s_index + 0] =
869         g->sb_hybrid[s_index + 1] =
870         g->sb_hybrid[s_index + 2] =
871         g->sb_hybrid[s_index + 3] = 0;
872         while (code) {
873             static const int idxtab[16] = { 3,3,2,2,1,1,1,1,0,0,0,0,0,0,0,0 };
874             int v;
875             int pos = s_index + idxtab[code];
876             code   ^= 8 >> idxtab[code];
877             READ_FLIP_SIGN(g->sb_hybrid + pos, RENAME(exp_table)+exponents[pos])
878         }
879         s_index += 4;
880     }
881     /* skip extension bits */
882     bits_left = end_pos2 - get_bits_count(&s->gb);
883     if (bits_left < 0 && (s->err_recognition & (AV_EF_BUFFER|AV_EF_COMPLIANT))) {
884         av_log(s->avctx, AV_LOG_ERROR, "bits_left=%d\n", bits_left);
885         s_index=0;
886     } else if (bits_left > 0 && (s->err_recognition & (AV_EF_BUFFER|AV_EF_AGGRESSIVE))) {
887         av_log(s->avctx, AV_LOG_ERROR, "bits_left=%d\n", bits_left);
888         s_index = 0;
889     }
890     memset(&g->sb_hybrid[s_index], 0, sizeof(*g->sb_hybrid) * (576 - s_index));
891     skip_bits_long(&s->gb, bits_left);
892 
893     i = get_bits_count(&s->gb);
894     switch_buffer(s, &i, &end_pos, &end_pos2);
895 
896     return 0;
897 }
898 
899 /* Reorder short blocks from bitstream order to interleaved order. It
900    would be faster to do it in parsing, but the code would be far more
901    complicated */
reorder_block(MPADecodeContext * s,GranuleDef * g)902 static void reorder_block(MPADecodeContext *s, GranuleDef *g)
903 {
904     int i, j, len;
905     INTFLOAT *ptr, *dst, *ptr1;
906     INTFLOAT tmp[576];
907 
908     if (g->block_type != 2)
909         return;
910 
911     if (g->switch_point) {
912         if (s->sample_rate_index != 8)
913             ptr = g->sb_hybrid + 36;
914         else
915             ptr = g->sb_hybrid + 72;
916     } else {
917         ptr = g->sb_hybrid;
918     }
919 
920     for (i = g->short_start; i < 13; i++) {
921         len  = ff_band_size_short[s->sample_rate_index][i];
922         ptr1 = ptr;
923         dst  = tmp;
924         for (j = len; j > 0; j--) {
925             *dst++ = ptr[0*len];
926             *dst++ = ptr[1*len];
927             *dst++ = ptr[2*len];
928             ptr++;
929         }
930         ptr += 2 * len;
931         memcpy(ptr1, tmp, len * 3 * sizeof(*ptr1));
932     }
933 }
934 
935 #define ISQRT2 FIXR(0.70710678118654752440)
936 
compute_stereo(MPADecodeContext * s,GranuleDef * g0,GranuleDef * g1)937 static void compute_stereo(MPADecodeContext *s, GranuleDef *g0, GranuleDef *g1)
938 {
939     int i, j, k, l;
940     int sf_max, sf, len, non_zero_found;
941     INTFLOAT *tab0, *tab1, v1, v2;
942     const INTFLOAT (*is_tab)[16];
943     SUINTFLOAT tmp0, tmp1;
944     int non_zero_found_short[3];
945 
946     /* intensity stereo */
947     if (s->mode_ext & MODE_EXT_I_STEREO) {
948         if (!s->lsf) {
949             is_tab = is_table;
950             sf_max = 7;
951         } else {
952             is_tab = is_table_lsf[g1->scalefac_compress & 1];
953             sf_max = 16;
954         }
955 
956         tab0 = g0->sb_hybrid + 576;
957         tab1 = g1->sb_hybrid + 576;
958 
959         non_zero_found_short[0] = 0;
960         non_zero_found_short[1] = 0;
961         non_zero_found_short[2] = 0;
962         k = (13 - g1->short_start) * 3 + g1->long_end - 3;
963         for (i = 12; i >= g1->short_start; i--) {
964             /* for last band, use previous scale factor */
965             if (i != 11)
966                 k -= 3;
967             len = ff_band_size_short[s->sample_rate_index][i];
968             for (l = 2; l >= 0; l--) {
969                 tab0 -= len;
970                 tab1 -= len;
971                 if (!non_zero_found_short[l]) {
972                     /* test if non zero band. if so, stop doing i-stereo */
973                     for (j = 0; j < len; j++) {
974                         if (tab1[j] != 0) {
975                             non_zero_found_short[l] = 1;
976                             goto found1;
977                         }
978                     }
979                     sf = g1->scale_factors[k + l];
980                     if (sf >= sf_max)
981                         goto found1;
982 
983                     v1 = is_tab[0][sf];
984                     v2 = is_tab[1][sf];
985                     for (j = 0; j < len; j++) {
986                         tmp0    = tab0[j];
987                         tab0[j] = MULLx(tmp0, v1, FRAC_BITS);
988                         tab1[j] = MULLx(tmp0, v2, FRAC_BITS);
989                     }
990                 } else {
991 found1:
992                     if (s->mode_ext & MODE_EXT_MS_STEREO) {
993                         /* lower part of the spectrum : do ms stereo
994                            if enabled */
995                         for (j = 0; j < len; j++) {
996                             tmp0    = tab0[j];
997                             tmp1    = tab1[j];
998                             tab0[j] = MULLx(tmp0 + tmp1, ISQRT2, FRAC_BITS);
999                             tab1[j] = MULLx(tmp0 - tmp1, ISQRT2, FRAC_BITS);
1000                         }
1001                     }
1002                 }
1003             }
1004         }
1005 
1006         non_zero_found = non_zero_found_short[0] |
1007                          non_zero_found_short[1] |
1008                          non_zero_found_short[2];
1009 
1010         for (i = g1->long_end - 1;i >= 0;i--) {
1011             len   = ff_band_size_long[s->sample_rate_index][i];
1012             tab0 -= len;
1013             tab1 -= len;
1014             /* test if non zero band. if so, stop doing i-stereo */
1015             if (!non_zero_found) {
1016                 for (j = 0; j < len; j++) {
1017                     if (tab1[j] != 0) {
1018                         non_zero_found = 1;
1019                         goto found2;
1020                     }
1021                 }
1022                 /* for last band, use previous scale factor */
1023                 k  = (i == 21) ? 20 : i;
1024                 sf = g1->scale_factors[k];
1025                 if (sf >= sf_max)
1026                     goto found2;
1027                 v1 = is_tab[0][sf];
1028                 v2 = is_tab[1][sf];
1029                 for (j = 0; j < len; j++) {
1030                     tmp0    = tab0[j];
1031                     tab0[j] = MULLx(tmp0, v1, FRAC_BITS);
1032                     tab1[j] = MULLx(tmp0, v2, FRAC_BITS);
1033                 }
1034             } else {
1035 found2:
1036                 if (s->mode_ext & MODE_EXT_MS_STEREO) {
1037                     /* lower part of the spectrum : do ms stereo
1038                        if enabled */
1039                     for (j = 0; j < len; j++) {
1040                         tmp0    = tab0[j];
1041                         tmp1    = tab1[j];
1042                         tab0[j] = MULLx(tmp0 + tmp1, ISQRT2, FRAC_BITS);
1043                         tab1[j] = MULLx(tmp0 - tmp1, ISQRT2, FRAC_BITS);
1044                     }
1045                 }
1046             }
1047         }
1048     } else if (s->mode_ext & MODE_EXT_MS_STEREO) {
1049         /* ms stereo ONLY */
1050         /* NOTE: the 1/sqrt(2) normalization factor is included in the
1051            global gain */
1052 #if USE_FLOATS
1053        s->butterflies_float(g0->sb_hybrid, g1->sb_hybrid, 576);
1054 #else
1055         tab0 = g0->sb_hybrid;
1056         tab1 = g1->sb_hybrid;
1057         for (i = 0; i < 576; i++) {
1058             tmp0    = tab0[i];
1059             tmp1    = tab1[i];
1060             tab0[i] = tmp0 + tmp1;
1061             tab1[i] = tmp0 - tmp1;
1062         }
1063 #endif
1064     }
1065 }
1066 
1067 #if USE_FLOATS
1068 #if HAVE_MIPSFPU
1069 #   include "mips/compute_antialias_float.h"
1070 #endif /* HAVE_MIPSFPU */
1071 #else
1072 #if HAVE_MIPSDSP
1073 #   include "mips/compute_antialias_fixed.h"
1074 #endif /* HAVE_MIPSDSP */
1075 #endif /* USE_FLOATS */
1076 
1077 #ifndef compute_antialias
1078 #if USE_FLOATS
1079 #define AA(j) do {                                                      \
1080         float tmp0 = ptr[-1-j];                                         \
1081         float tmp1 = ptr[   j];                                         \
1082         ptr[-1-j] = tmp0 * csa_table[j][0] - tmp1 * csa_table[j][1];    \
1083         ptr[   j] = tmp0 * csa_table[j][1] + tmp1 * csa_table[j][0];    \
1084     } while (0)
1085 #else
1086 #define AA(j) do {                                              \
1087         SUINT tmp0 = ptr[-1-j];                                   \
1088         SUINT tmp1 = ptr[   j];                                   \
1089         SUINT tmp2 = MULH(tmp0 + tmp1, csa_table[j][0]);          \
1090         ptr[-1-j] = 4 * (tmp2 - MULH(tmp1, csa_table[j][2]));   \
1091         ptr[   j] = 4 * (tmp2 + MULH(tmp0, csa_table[j][3]));   \
1092     } while (0)
1093 #endif
1094 
compute_antialias(MPADecodeContext * s,GranuleDef * g)1095 static void compute_antialias(MPADecodeContext *s, GranuleDef *g)
1096 {
1097     INTFLOAT *ptr;
1098     int n, i;
1099 
1100     /* we antialias only "long" bands */
1101     if (g->block_type == 2) {
1102         if (!g->switch_point)
1103             return;
1104         /* XXX: check this for 8000Hz case */
1105         n = 1;
1106     } else {
1107         n = SBLIMIT - 1;
1108     }
1109 
1110     ptr = g->sb_hybrid + 18;
1111     for (i = n; i > 0; i--) {
1112         AA(0);
1113         AA(1);
1114         AA(2);
1115         AA(3);
1116         AA(4);
1117         AA(5);
1118         AA(6);
1119         AA(7);
1120 
1121         ptr += 18;
1122     }
1123 }
1124 #endif /* compute_antialias */
1125 
compute_imdct(MPADecodeContext * s,GranuleDef * g,INTFLOAT * sb_samples,INTFLOAT * mdct_buf)1126 static void compute_imdct(MPADecodeContext *s, GranuleDef *g,
1127                           INTFLOAT *sb_samples, INTFLOAT *mdct_buf)
1128 {
1129     INTFLOAT *win, *out_ptr, *ptr, *buf, *ptr1;
1130     INTFLOAT out2[12];
1131     int i, j, mdct_long_end, sblimit;
1132 
1133     /* find last non zero block */
1134     ptr  = g->sb_hybrid + 576;
1135     ptr1 = g->sb_hybrid + 2 * 18;
1136     while (ptr >= ptr1) {
1137         int32_t *p;
1138         ptr -= 6;
1139         p    = (int32_t*)ptr;
1140         if (p[0] | p[1] | p[2] | p[3] | p[4] | p[5])
1141             break;
1142     }
1143     sblimit = ((ptr - g->sb_hybrid) / 18) + 1;
1144 
1145     if (g->block_type == 2) {
1146         /* XXX: check for 8000 Hz */
1147         if (g->switch_point)
1148             mdct_long_end = 2;
1149         else
1150             mdct_long_end = 0;
1151     } else {
1152         mdct_long_end = sblimit;
1153     }
1154 
1155     s->mpadsp.RENAME(imdct36_blocks)(sb_samples, mdct_buf, g->sb_hybrid,
1156                                      mdct_long_end, g->switch_point,
1157                                      g->block_type);
1158 
1159     buf = mdct_buf + 4*18*(mdct_long_end >> 2) + (mdct_long_end & 3);
1160     ptr = g->sb_hybrid + 18 * mdct_long_end;
1161 
1162     for (j = mdct_long_end; j < sblimit; j++) {
1163         /* select frequency inversion */
1164         win     = RENAME(ff_mdct_win)[2 + (4  & -(j & 1))];
1165         out_ptr = sb_samples + j;
1166 
1167         for (i = 0; i < 6; i++) {
1168             *out_ptr = buf[4*i];
1169             out_ptr += SBLIMIT;
1170         }
1171         imdct12(out2, ptr + 0);
1172         for (i = 0; i < 6; i++) {
1173             *out_ptr     = MULH3(out2[i    ], win[i    ], 1) + buf[4*(i + 6*1)];
1174             buf[4*(i + 6*2)] = MULH3(out2[i + 6], win[i + 6], 1);
1175             out_ptr += SBLIMIT;
1176         }
1177         imdct12(out2, ptr + 1);
1178         for (i = 0; i < 6; i++) {
1179             *out_ptr     = MULH3(out2[i    ], win[i    ], 1) + buf[4*(i + 6*2)];
1180             buf[4*(i + 6*0)] = MULH3(out2[i + 6], win[i + 6], 1);
1181             out_ptr += SBLIMIT;
1182         }
1183         imdct12(out2, ptr + 2);
1184         for (i = 0; i < 6; i++) {
1185             buf[4*(i + 6*0)] = MULH3(out2[i    ], win[i    ], 1) + buf[4*(i + 6*0)];
1186             buf[4*(i + 6*1)] = MULH3(out2[i + 6], win[i + 6], 1);
1187             buf[4*(i + 6*2)] = 0;
1188         }
1189         ptr += 18;
1190         buf += (j&3) != 3 ? 1 : (4*18-3);
1191     }
1192     /* zero bands */
1193     for (j = sblimit; j < SBLIMIT; j++) {
1194         /* overlap */
1195         out_ptr = sb_samples + j;
1196         for (i = 0; i < 18; i++) {
1197             *out_ptr = buf[4*i];
1198             buf[4*i]   = 0;
1199             out_ptr += SBLIMIT;
1200         }
1201         buf += (j&3) != 3 ? 1 : (4*18-3);
1202     }
1203 }
1204 
1205 /* main layer3 decoding function */
mp_decode_layer3(MPADecodeContext * s)1206 static int mp_decode_layer3(MPADecodeContext *s)
1207 {
1208     int nb_granules, main_data_begin;
1209     int gr, ch, blocksplit_flag, i, j, k, n, bits_pos;
1210     GranuleDef *g;
1211     int16_t exponents[576]; //FIXME try INTFLOAT
1212     int ret;
1213 
1214     /* read side info */
1215     if (s->lsf) {
1216         ret = handle_crc(s, ((s->nb_channels == 1) ? 8*9  : 8*17));
1217         main_data_begin = get_bits(&s->gb, 8);
1218         skip_bits(&s->gb, s->nb_channels);
1219         nb_granules = 1;
1220     } else {
1221         ret = handle_crc(s, ((s->nb_channels == 1) ? 8*17 : 8*32));
1222         main_data_begin = get_bits(&s->gb, 9);
1223         if (s->nb_channels == 2)
1224             skip_bits(&s->gb, 3);
1225         else
1226             skip_bits(&s->gb, 5);
1227         nb_granules = 2;
1228         for (ch = 0; ch < s->nb_channels; ch++) {
1229             s->granules[ch][0].scfsi = 0;/* all scale factors are transmitted */
1230             s->granules[ch][1].scfsi = get_bits(&s->gb, 4);
1231         }
1232     }
1233     if (ret < 0)
1234         return ret;
1235 
1236     for (gr = 0; gr < nb_granules; gr++) {
1237         for (ch = 0; ch < s->nb_channels; ch++) {
1238             ff_dlog(s->avctx, "gr=%d ch=%d: side_info\n", gr, ch);
1239             g = &s->granules[ch][gr];
1240             g->part2_3_length = get_bits(&s->gb, 12);
1241             g->big_values     = get_bits(&s->gb,  9);
1242             if (g->big_values > 288) {
1243                 av_log(s->avctx, AV_LOG_ERROR, "big_values too big\n");
1244                 return AVERROR_INVALIDDATA;
1245             }
1246 
1247             g->global_gain = get_bits(&s->gb, 8);
1248             /* if MS stereo only is selected, we precompute the
1249                1/sqrt(2) renormalization factor */
1250             if ((s->mode_ext & (MODE_EXT_MS_STEREO | MODE_EXT_I_STEREO)) ==
1251                 MODE_EXT_MS_STEREO)
1252                 g->global_gain -= 2;
1253             if (s->lsf)
1254                 g->scalefac_compress = get_bits(&s->gb, 9);
1255             else
1256                 g->scalefac_compress = get_bits(&s->gb, 4);
1257             blocksplit_flag = get_bits1(&s->gb);
1258             if (blocksplit_flag) {
1259                 g->block_type = get_bits(&s->gb, 2);
1260                 if (g->block_type == 0) {
1261                     av_log(s->avctx, AV_LOG_ERROR, "invalid block type\n");
1262                     return AVERROR_INVALIDDATA;
1263                 }
1264                 g->switch_point = get_bits1(&s->gb);
1265                 for (i = 0; i < 2; i++)
1266                     g->table_select[i] = get_bits(&s->gb, 5);
1267                 for (i = 0; i < 3; i++)
1268                     g->subblock_gain[i] = get_bits(&s->gb, 3);
1269                 init_short_region(s, g);
1270             } else {
1271                 int region_address1, region_address2;
1272                 g->block_type = 0;
1273                 g->switch_point = 0;
1274                 for (i = 0; i < 3; i++)
1275                     g->table_select[i] = get_bits(&s->gb, 5);
1276                 /* compute huffman coded region sizes */
1277                 region_address1 = get_bits(&s->gb, 4);
1278                 region_address2 = get_bits(&s->gb, 3);
1279                 ff_dlog(s->avctx, "region1=%d region2=%d\n",
1280                         region_address1, region_address2);
1281                 init_long_region(s, g, region_address1, region_address2);
1282             }
1283             region_offset2size(g);
1284             compute_band_indexes(s, g);
1285 
1286             g->preflag = 0;
1287             if (!s->lsf)
1288                 g->preflag = get_bits1(&s->gb);
1289             g->scalefac_scale     = get_bits1(&s->gb);
1290             g->count1table_select = get_bits1(&s->gb);
1291             ff_dlog(s->avctx, "block_type=%d switch_point=%d\n",
1292                     g->block_type, g->switch_point);
1293         }
1294     }
1295 
1296     if (!s->adu_mode) {
1297         int skip;
1298         const uint8_t *ptr = s->gb.buffer + (get_bits_count(&s->gb) >> 3);
1299         s->extrasize = av_clip((get_bits_left(&s->gb) >> 3) - s->extrasize, 0,
1300                                FFMAX(0, LAST_BUF_SIZE - s->last_buf_size));
1301         av_assert1((get_bits_count(&s->gb) & 7) == 0);
1302         /* now we get bits from the main_data_begin offset */
1303         ff_dlog(s->avctx, "seekback:%d, lastbuf:%d\n",
1304                 main_data_begin, s->last_buf_size);
1305 
1306         memcpy(s->last_buf + s->last_buf_size, ptr, s->extrasize);
1307         s->in_gb = s->gb;
1308         init_get_bits(&s->gb, s->last_buf, (s->last_buf_size + s->extrasize) * 8);
1309         s->last_buf_size <<= 3;
1310         for (gr = 0; gr < nb_granules && (s->last_buf_size >> 3) < main_data_begin; gr++) {
1311             for (ch = 0; ch < s->nb_channels; ch++) {
1312                 g = &s->granules[ch][gr];
1313                 s->last_buf_size += g->part2_3_length;
1314                 memset(g->sb_hybrid, 0, sizeof(g->sb_hybrid));
1315                 compute_imdct(s, g, &s->sb_samples[ch][18 * gr][0], s->mdct_buf[ch]);
1316             }
1317         }
1318         skip = s->last_buf_size - 8 * main_data_begin;
1319         if (skip >= s->gb.size_in_bits - s->extrasize * 8 && s->in_gb.buffer) {
1320             skip_bits_long(&s->in_gb, skip - s->gb.size_in_bits + s->extrasize * 8);
1321             s->gb           = s->in_gb;
1322             s->in_gb.buffer = NULL;
1323             s->extrasize    = 0;
1324         } else {
1325             skip_bits_long(&s->gb, skip);
1326         }
1327     } else {
1328         gr = 0;
1329         s->extrasize = 0;
1330     }
1331 
1332     for (; gr < nb_granules; gr++) {
1333         for (ch = 0; ch < s->nb_channels; ch++) {
1334             g = &s->granules[ch][gr];
1335             bits_pos = get_bits_count(&s->gb);
1336 
1337             if (!s->lsf) {
1338                 uint8_t *sc;
1339                 int slen, slen1, slen2;
1340 
1341                 /* MPEG-1 scale factors */
1342                 slen1 = ff_slen_table[0][g->scalefac_compress];
1343                 slen2 = ff_slen_table[1][g->scalefac_compress];
1344                 ff_dlog(s->avctx, "slen1=%d slen2=%d\n", slen1, slen2);
1345                 if (g->block_type == 2) {
1346                     n = g->switch_point ? 17 : 18;
1347                     j = 0;
1348                     if (slen1) {
1349                         for (i = 0; i < n; i++)
1350                             g->scale_factors[j++] = get_bits(&s->gb, slen1);
1351                     } else {
1352                         for (i = 0; i < n; i++)
1353                             g->scale_factors[j++] = 0;
1354                     }
1355                     if (slen2) {
1356                         for (i = 0; i < 18; i++)
1357                             g->scale_factors[j++] = get_bits(&s->gb, slen2);
1358                         for (i = 0; i < 3; i++)
1359                             g->scale_factors[j++] = 0;
1360                     } else {
1361                         for (i = 0; i < 21; i++)
1362                             g->scale_factors[j++] = 0;
1363                     }
1364                 } else {
1365                     sc = s->granules[ch][0].scale_factors;
1366                     j = 0;
1367                     for (k = 0; k < 4; k++) {
1368                         n = k == 0 ? 6 : 5;
1369                         if ((g->scfsi & (0x8 >> k)) == 0) {
1370                             slen = (k < 2) ? slen1 : slen2;
1371                             if (slen) {
1372                                 for (i = 0; i < n; i++)
1373                                     g->scale_factors[j++] = get_bits(&s->gb, slen);
1374                             } else {
1375                                 for (i = 0; i < n; i++)
1376                                     g->scale_factors[j++] = 0;
1377                             }
1378                         } else {
1379                             /* simply copy from last granule */
1380                             for (i = 0; i < n; i++) {
1381                                 g->scale_factors[j] = sc[j];
1382                                 j++;
1383                             }
1384                         }
1385                     }
1386                     g->scale_factors[j++] = 0;
1387                 }
1388             } else {
1389                 int tindex, tindex2, slen[4], sl, sf;
1390 
1391                 /* LSF scale factors */
1392                 if (g->block_type == 2)
1393                     tindex = g->switch_point ? 2 : 1;
1394                 else
1395                     tindex = 0;
1396 
1397                 sf = g->scalefac_compress;
1398                 if ((s->mode_ext & MODE_EXT_I_STEREO) && ch == 1) {
1399                     /* intensity stereo case */
1400                     sf >>= 1;
1401                     if (sf < 180) {
1402                         lsf_sf_expand(slen, sf, 6, 6, 0);
1403                         tindex2 = 3;
1404                     } else if (sf < 244) {
1405                         lsf_sf_expand(slen, sf - 180, 4, 4, 0);
1406                         tindex2 = 4;
1407                     } else {
1408                         lsf_sf_expand(slen, sf - 244, 3, 0, 0);
1409                         tindex2 = 5;
1410                     }
1411                 } else {
1412                     /* normal case */
1413                     if (sf < 400) {
1414                         lsf_sf_expand(slen, sf, 5, 4, 4);
1415                         tindex2 = 0;
1416                     } else if (sf < 500) {
1417                         lsf_sf_expand(slen, sf - 400, 5, 4, 0);
1418                         tindex2 = 1;
1419                     } else {
1420                         lsf_sf_expand(slen, sf - 500, 3, 0, 0);
1421                         tindex2 = 2;
1422                         g->preflag = 1;
1423                     }
1424                 }
1425 
1426                 j = 0;
1427                 for (k = 0; k < 4; k++) {
1428                     n  = ff_lsf_nsf_table[tindex2][tindex][k];
1429                     sl = slen[k];
1430                     if (sl) {
1431                         for (i = 0; i < n; i++)
1432                             g->scale_factors[j++] = get_bits(&s->gb, sl);
1433                     } else {
1434                         for (i = 0; i < n; i++)
1435                             g->scale_factors[j++] = 0;
1436                     }
1437                 }
1438                 /* XXX: should compute exact size */
1439                 for (; j < 40; j++)
1440                     g->scale_factors[j] = 0;
1441             }
1442 
1443             exponents_from_scale_factors(s, g, exponents);
1444 
1445             /* read Huffman coded residue */
1446             huffman_decode(s, g, exponents, bits_pos + g->part2_3_length);
1447         } /* ch */
1448 
1449         if (s->mode == MPA_JSTEREO)
1450             compute_stereo(s, &s->granules[0][gr], &s->granules[1][gr]);
1451 
1452         for (ch = 0; ch < s->nb_channels; ch++) {
1453             g = &s->granules[ch][gr];
1454 
1455             reorder_block(s, g);
1456             compute_antialias(s, g);
1457             compute_imdct(s, g, &s->sb_samples[ch][18 * gr][0], s->mdct_buf[ch]);
1458         }
1459     } /* gr */
1460     if (get_bits_count(&s->gb) < 0)
1461         skip_bits_long(&s->gb, -get_bits_count(&s->gb));
1462     return nb_granules * 18;
1463 }
1464 
mp_decode_frame(MPADecodeContext * s,OUT_INT ** samples,const uint8_t * buf,int buf_size)1465 static int mp_decode_frame(MPADecodeContext *s, OUT_INT **samples,
1466                            const uint8_t *buf, int buf_size)
1467 {
1468     int i, nb_frames, ch, ret;
1469     OUT_INT *samples_ptr;
1470 
1471     init_get_bits(&s->gb, buf + HEADER_SIZE, (buf_size - HEADER_SIZE) * 8);
1472     if (s->error_protection)
1473         s->crc = get_bits(&s->gb, 16);
1474 
1475     switch(s->layer) {
1476     case 1:
1477         s->avctx->frame_size = 384;
1478         nb_frames = mp_decode_layer1(s);
1479         break;
1480     case 2:
1481         s->avctx->frame_size = 1152;
1482         nb_frames = mp_decode_layer2(s);
1483         break;
1484     case 3:
1485         s->avctx->frame_size = s->lsf ? 576 : 1152;
1486     default:
1487         nb_frames = mp_decode_layer3(s);
1488 
1489         s->last_buf_size=0;
1490         if (s->in_gb.buffer) {
1491             align_get_bits(&s->gb);
1492             i = (get_bits_left(&s->gb) >> 3) - s->extrasize;
1493             if (i >= 0 && i <= BACKSTEP_SIZE) {
1494                 memmove(s->last_buf, s->gb.buffer + (get_bits_count(&s->gb) >> 3), i);
1495                 s->last_buf_size=i;
1496             } else
1497                 av_log(s->avctx, AV_LOG_ERROR, "invalid old backstep %d\n", i);
1498             s->gb           = s->in_gb;
1499             s->in_gb.buffer = NULL;
1500             s->extrasize    = 0;
1501         }
1502 
1503         align_get_bits(&s->gb);
1504         av_assert1((get_bits_count(&s->gb) & 7) == 0);
1505         i = (get_bits_left(&s->gb) >> 3) - s->extrasize;
1506         if (i < 0 || i > BACKSTEP_SIZE || nb_frames < 0) {
1507             if (i < 0)
1508                 av_log(s->avctx, AV_LOG_ERROR, "invalid new backstep %d\n", i);
1509             i = FFMIN(BACKSTEP_SIZE, buf_size - HEADER_SIZE);
1510         }
1511         av_assert1(i <= buf_size - HEADER_SIZE && i >= 0);
1512         memcpy(s->last_buf + s->last_buf_size, s->gb.buffer + buf_size - HEADER_SIZE - i, i);
1513         s->last_buf_size += i;
1514     }
1515 
1516     if(nb_frames < 0)
1517         return nb_frames;
1518 
1519     /* get output buffer */
1520     if (!samples) {
1521         av_assert0(s->frame);
1522         s->frame->nb_samples = s->avctx->frame_size;
1523         if ((ret = ff_get_buffer(s->avctx, s->frame, 0)) < 0)
1524             return ret;
1525         samples = (OUT_INT **)s->frame->extended_data;
1526     }
1527 
1528     /* apply the synthesis filter */
1529     for (ch = 0; ch < s->nb_channels; ch++) {
1530         int sample_stride;
1531         if (s->avctx->sample_fmt == OUT_FMT_P) {
1532             samples_ptr   = samples[ch];
1533             sample_stride = 1;
1534         } else {
1535             samples_ptr   = samples[0] + ch;
1536             sample_stride = s->nb_channels;
1537         }
1538         for (i = 0; i < nb_frames; i++) {
1539             RENAME(ff_mpa_synth_filter)(&s->mpadsp, s->synth_buf[ch],
1540                                         &(s->synth_buf_offset[ch]),
1541                                         RENAME(ff_mpa_synth_window),
1542                                         &s->dither_state, samples_ptr,
1543                                         sample_stride, s->sb_samples[ch][i]);
1544             samples_ptr += 32 * sample_stride;
1545         }
1546     }
1547 
1548     return nb_frames * 32 * sizeof(OUT_INT) * s->nb_channels;
1549 }
1550 
decode_frame(AVCodecContext * avctx,AVFrame * frame,int * got_frame_ptr,AVPacket * avpkt)1551 static int decode_frame(AVCodecContext *avctx, AVFrame *frame,
1552                         int *got_frame_ptr, AVPacket *avpkt)
1553 {
1554     const uint8_t *buf  = avpkt->data;
1555     int buf_size        = avpkt->size;
1556     MPADecodeContext *s = avctx->priv_data;
1557     uint32_t header;
1558     int ret;
1559 
1560     int skipped = 0;
1561     while(buf_size && !*buf){
1562         buf++;
1563         buf_size--;
1564         skipped++;
1565     }
1566 
1567     if (buf_size < HEADER_SIZE)
1568         return AVERROR_INVALIDDATA;
1569 
1570     header = AV_RB32(buf);
1571     if (header >> 8 == AV_RB32("TAG") >> 8) {
1572         av_log(avctx, AV_LOG_DEBUG, "discarding ID3 tag\n");
1573         return buf_size + skipped;
1574     }
1575     ret = avpriv_mpegaudio_decode_header((MPADecodeHeader *)s, header);
1576     if (ret < 0) {
1577         av_log(avctx, AV_LOG_ERROR, "Header missing\n");
1578         return AVERROR_INVALIDDATA;
1579     } else if (ret == 1) {
1580         /* free format: prepare to compute frame size */
1581         s->frame_size = -1;
1582         return AVERROR_INVALIDDATA;
1583     }
1584     /* update codec info */
1585     av_channel_layout_uninit(&avctx->ch_layout);
1586     avctx->ch_layout = s->nb_channels == 1 ? (AVChannelLayout)AV_CHANNEL_LAYOUT_MONO :
1587                                              (AVChannelLayout)AV_CHANNEL_LAYOUT_STEREO;
1588     if (!avctx->bit_rate)
1589         avctx->bit_rate = s->bit_rate;
1590 
1591     if (s->frame_size <= 0) {
1592         av_log(avctx, AV_LOG_ERROR, "incomplete frame\n");
1593         return AVERROR_INVALIDDATA;
1594     } else if (s->frame_size < buf_size) {
1595         av_log(avctx, AV_LOG_DEBUG, "incorrect frame size - multiple frames in buffer?\n");
1596         buf_size= s->frame_size;
1597     }
1598 
1599     s->frame = frame;
1600 
1601     ret = mp_decode_frame(s, NULL, buf, buf_size);
1602     if (ret >= 0) {
1603         s->frame->nb_samples = avctx->frame_size;
1604         *got_frame_ptr       = 1;
1605         avctx->sample_rate   = s->sample_rate;
1606         //FIXME maybe move the other codec info stuff from above here too
1607     } else {
1608         av_log(avctx, AV_LOG_ERROR, "Error while decoding MPEG audio frame.\n");
1609         /* Only return an error if the bad frame makes up the whole packet or
1610          * the error is related to buffer management.
1611          * If there is more data in the packet, just consume the bad frame
1612          * instead of returning an error, which would discard the whole
1613          * packet. */
1614         *got_frame_ptr = 0;
1615         if (buf_size == avpkt->size || ret != AVERROR_INVALIDDATA)
1616             return ret;
1617     }
1618     s->frame_size = 0;
1619     return buf_size + skipped;
1620 }
1621 
mp_flush(MPADecodeContext * ctx)1622 static void mp_flush(MPADecodeContext *ctx)
1623 {
1624     memset(ctx->synth_buf, 0, sizeof(ctx->synth_buf));
1625     memset(ctx->mdct_buf, 0, sizeof(ctx->mdct_buf));
1626     ctx->last_buf_size = 0;
1627     ctx->dither_state = 0;
1628 }
1629 
flush(AVCodecContext * avctx)1630 static void flush(AVCodecContext *avctx)
1631 {
1632     mp_flush(avctx->priv_data);
1633 }
1634 
1635 #if CONFIG_MP3ADU_DECODER || CONFIG_MP3ADUFLOAT_DECODER
decode_frame_adu(AVCodecContext * avctx,AVFrame * frame,int * got_frame_ptr,AVPacket * avpkt)1636 static int decode_frame_adu(AVCodecContext *avctx, AVFrame *frame,
1637                             int *got_frame_ptr, AVPacket *avpkt)
1638 {
1639     const uint8_t *buf  = avpkt->data;
1640     int buf_size        = avpkt->size;
1641     MPADecodeContext *s = avctx->priv_data;
1642     uint32_t header;
1643     int len, ret;
1644 
1645     len = buf_size;
1646 
1647     // Discard too short frames
1648     if (buf_size < HEADER_SIZE) {
1649         av_log(avctx, AV_LOG_ERROR, "Packet is too small\n");
1650         return AVERROR_INVALIDDATA;
1651     }
1652 
1653 
1654     if (len > MPA_MAX_CODED_FRAME_SIZE)
1655         len = MPA_MAX_CODED_FRAME_SIZE;
1656 
1657     // Get header and restore sync word
1658     header = AV_RB32(buf) | 0xffe00000;
1659 
1660     ret = avpriv_mpegaudio_decode_header((MPADecodeHeader *)s, header);
1661     if (ret < 0) {
1662         av_log(avctx, AV_LOG_ERROR, "Invalid frame header\n");
1663         return ret;
1664     }
1665     /* update codec info */
1666     avctx->sample_rate = s->sample_rate;
1667     av_channel_layout_uninit(&avctx->ch_layout);
1668     avctx->ch_layout = s->nb_channels == 1 ? (AVChannelLayout)AV_CHANNEL_LAYOUT_MONO :
1669                                              (AVChannelLayout)AV_CHANNEL_LAYOUT_STEREO;
1670     if (!avctx->bit_rate)
1671         avctx->bit_rate = s->bit_rate;
1672 
1673     s->frame_size = len;
1674 
1675     s->frame = frame;
1676 
1677     ret = mp_decode_frame(s, NULL, buf, buf_size);
1678     if (ret < 0) {
1679         av_log(avctx, AV_LOG_ERROR, "Error while decoding MPEG audio frame.\n");
1680         return ret;
1681     }
1682 
1683     *got_frame_ptr = 1;
1684 
1685     return buf_size;
1686 }
1687 #endif /* CONFIG_MP3ADU_DECODER || CONFIG_MP3ADUFLOAT_DECODER */
1688 
1689 #if CONFIG_MP3ON4_DECODER || CONFIG_MP3ON4FLOAT_DECODER
1690 
1691 /**
1692  * Context for MP3On4 decoder
1693  */
1694 typedef struct MP3On4DecodeContext {
1695     int frames;                     ///< number of mp3 frames per block (number of mp3 decoder instances)
1696     int syncword;                   ///< syncword patch
1697     const uint8_t *coff;            ///< channel offsets in output buffer
1698     MPADecodeContext *mp3decctx[5]; ///< MPADecodeContext for every decoder instance
1699 } MP3On4DecodeContext;
1700 
1701 #include "mpeg4audio.h"
1702 
1703 /* Next 3 arrays are indexed by channel config number (passed via codecdata) */
1704 
1705 /* number of mp3 decoder instances */
1706 static const uint8_t mp3Frames[8] = { 0, 1, 1, 2, 3, 3, 4, 5 };
1707 
1708 /* offsets into output buffer, assume output order is FL FR C LFE BL BR SL SR */
1709 static const uint8_t chan_offset[8][5] = {
1710     { 0             },
1711     { 0             },  // C
1712     { 0             },  // FLR
1713     { 2, 0          },  // C FLR
1714     { 2, 0, 3       },  // C FLR BS
1715     { 2, 0, 3       },  // C FLR BLRS
1716     { 2, 0, 4, 3    },  // C FLR BLRS LFE
1717     { 2, 0, 6, 4, 3 },  // C FLR BLRS BLR LFE
1718 };
1719 
1720 /* mp3on4 channel layouts */
1721 static const int16_t chan_layout[8] = {
1722     0,
1723     AV_CH_LAYOUT_MONO,
1724     AV_CH_LAYOUT_STEREO,
1725     AV_CH_LAYOUT_SURROUND,
1726     AV_CH_LAYOUT_4POINT0,
1727     AV_CH_LAYOUT_5POINT0,
1728     AV_CH_LAYOUT_5POINT1,
1729     AV_CH_LAYOUT_7POINT1
1730 };
1731 
decode_close_mp3on4(AVCodecContext * avctx)1732 static av_cold int decode_close_mp3on4(AVCodecContext * avctx)
1733 {
1734     MP3On4DecodeContext *s = avctx->priv_data;
1735     int i;
1736 
1737     for (i = 0; i < s->frames; i++)
1738         av_freep(&s->mp3decctx[i]);
1739 
1740     return 0;
1741 }
1742 
1743 
decode_init_mp3on4(AVCodecContext * avctx)1744 static av_cold int decode_init_mp3on4(AVCodecContext * avctx)
1745 {
1746     MP3On4DecodeContext *s = avctx->priv_data;
1747     MPEG4AudioConfig cfg;
1748     int i, ret;
1749 
1750     if ((avctx->extradata_size < 2) || !avctx->extradata) {
1751         av_log(avctx, AV_LOG_ERROR, "Codec extradata missing or too short.\n");
1752         return AVERROR_INVALIDDATA;
1753     }
1754 
1755     avpriv_mpeg4audio_get_config2(&cfg, avctx->extradata,
1756                                   avctx->extradata_size, 1, avctx);
1757     if (!cfg.chan_config || cfg.chan_config > 7) {
1758         av_log(avctx, AV_LOG_ERROR, "Invalid channel config number.\n");
1759         return AVERROR_INVALIDDATA;
1760     }
1761     s->frames             = mp3Frames[cfg.chan_config];
1762     s->coff               = chan_offset[cfg.chan_config];
1763     av_channel_layout_uninit(&avctx->ch_layout);
1764     av_channel_layout_from_mask(&avctx->ch_layout, chan_layout[cfg.chan_config]);
1765 
1766     if (cfg.sample_rate < 16000)
1767         s->syncword = 0xffe00000;
1768     else
1769         s->syncword = 0xfff00000;
1770 
1771     /* Init the first mp3 decoder in standard way, so that all tables get builded
1772      * We replace avctx->priv_data with the context of the first decoder so that
1773      * decode_init() does not have to be changed.
1774      * Other decoders will be initialized here copying data from the first context
1775      */
1776     // Allocate zeroed memory for the first decoder context
1777     s->mp3decctx[0] = av_mallocz(sizeof(MPADecodeContext));
1778     if (!s->mp3decctx[0])
1779         return AVERROR(ENOMEM);
1780     // Put decoder context in place to make init_decode() happy
1781     avctx->priv_data = s->mp3decctx[0];
1782     ret = decode_init(avctx);
1783     // Restore mp3on4 context pointer
1784     avctx->priv_data = s;
1785     if (ret < 0)
1786         return ret;
1787     s->mp3decctx[0]->adu_mode = 1; // Set adu mode
1788 
1789     /* Create a separate codec/context for each frame (first is already ok).
1790      * Each frame is 1 or 2 channels - up to 5 frames allowed
1791      */
1792     for (i = 1; i < s->frames; i++) {
1793         s->mp3decctx[i] = av_mallocz(sizeof(MPADecodeContext));
1794         if (!s->mp3decctx[i])
1795             return AVERROR(ENOMEM);
1796         s->mp3decctx[i]->adu_mode = 1;
1797         s->mp3decctx[i]->avctx = avctx;
1798         s->mp3decctx[i]->mpadsp = s->mp3decctx[0]->mpadsp;
1799         s->mp3decctx[i]->butterflies_float = s->mp3decctx[0]->butterflies_float;
1800     }
1801 
1802     return 0;
1803 }
1804 
1805 
flush_mp3on4(AVCodecContext * avctx)1806 static void flush_mp3on4(AVCodecContext *avctx)
1807 {
1808     int i;
1809     MP3On4DecodeContext *s = avctx->priv_data;
1810 
1811     for (i = 0; i < s->frames; i++)
1812         mp_flush(s->mp3decctx[i]);
1813 }
1814 
1815 
decode_frame_mp3on4(AVCodecContext * avctx,AVFrame * frame,int * got_frame_ptr,AVPacket * avpkt)1816 static int decode_frame_mp3on4(AVCodecContext *avctx, AVFrame *frame,
1817                                int *got_frame_ptr, AVPacket *avpkt)
1818 {
1819     const uint8_t *buf     = avpkt->data;
1820     int buf_size           = avpkt->size;
1821     MP3On4DecodeContext *s = avctx->priv_data;
1822     MPADecodeContext *m;
1823     int fsize, len = buf_size, out_size = 0;
1824     uint32_t header;
1825     OUT_INT **out_samples;
1826     OUT_INT *outptr[2];
1827     int fr, ch, ret;
1828 
1829     /* get output buffer */
1830     frame->nb_samples = MPA_FRAME_SIZE;
1831     if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
1832         return ret;
1833     out_samples = (OUT_INT **)frame->extended_data;
1834 
1835     // Discard too short frames
1836     if (buf_size < HEADER_SIZE)
1837         return AVERROR_INVALIDDATA;
1838 
1839     avctx->bit_rate = 0;
1840 
1841     ch = 0;
1842     for (fr = 0; fr < s->frames; fr++) {
1843         fsize = AV_RB16(buf) >> 4;
1844         fsize = FFMIN3(fsize, len, MPA_MAX_CODED_FRAME_SIZE);
1845         m     = s->mp3decctx[fr];
1846         av_assert1(m);
1847 
1848         if (fsize < HEADER_SIZE) {
1849             av_log(avctx, AV_LOG_ERROR, "Frame size smaller than header size\n");
1850             return AVERROR_INVALIDDATA;
1851         }
1852         header = (AV_RB32(buf) & 0x000fffff) | s->syncword; // patch header
1853 
1854         ret = avpriv_mpegaudio_decode_header((MPADecodeHeader *)m, header);
1855         if (ret < 0) {
1856             av_log(avctx, AV_LOG_ERROR, "Bad header, discard block\n");
1857             return AVERROR_INVALIDDATA;
1858         }
1859 
1860         if (ch + m->nb_channels > avctx->ch_layout.nb_channels ||
1861             s->coff[fr] + m->nb_channels > avctx->ch_layout.nb_channels) {
1862             av_log(avctx, AV_LOG_ERROR, "frame channel count exceeds codec "
1863                                         "channel count\n");
1864             return AVERROR_INVALIDDATA;
1865         }
1866         ch += m->nb_channels;
1867 
1868         outptr[0] = out_samples[s->coff[fr]];
1869         if (m->nb_channels > 1)
1870             outptr[1] = out_samples[s->coff[fr] + 1];
1871 
1872         if ((ret = mp_decode_frame(m, outptr, buf, fsize)) < 0) {
1873             av_log(avctx, AV_LOG_ERROR, "failed to decode channel %d\n", ch);
1874             memset(outptr[0], 0, MPA_FRAME_SIZE*sizeof(OUT_INT));
1875             if (m->nb_channels > 1)
1876                 memset(outptr[1], 0, MPA_FRAME_SIZE*sizeof(OUT_INT));
1877             ret = m->nb_channels * MPA_FRAME_SIZE*sizeof(OUT_INT);
1878         }
1879 
1880         out_size += ret;
1881         buf      += fsize;
1882         len      -= fsize;
1883 
1884         avctx->bit_rate += m->bit_rate;
1885     }
1886     if (ch != avctx->ch_layout.nb_channels) {
1887         av_log(avctx, AV_LOG_ERROR, "failed to decode all channels\n");
1888         return AVERROR_INVALIDDATA;
1889     }
1890 
1891     /* update codec info */
1892     avctx->sample_rate = s->mp3decctx[0]->sample_rate;
1893 
1894     frame->nb_samples = out_size / (avctx->ch_layout.nb_channels * sizeof(OUT_INT));
1895     *got_frame_ptr    = 1;
1896 
1897     return buf_size;
1898 }
1899 #endif /* CONFIG_MP3ON4_DECODER || CONFIG_MP3ON4FLOAT_DECODER */
1900