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" */
57typedef 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
76typedef 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 */
106static INTFLOAT is_table_lsf[2][2][16];
107
108/* [i][j]:  2^(-j/3) * FRAC_ONE * 2^(i+2) / (2^(i+2) - 1) */
109static 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
115static 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 */
125static 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
136static 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
154static 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
164static 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 */
191static 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
205static 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 */
221static 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
240static 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
282static 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. */
324static 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
365static 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 */
392static 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
462static 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
674static 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
683static 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
720static 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
751static 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 */
902static 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
937static 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 {
991found1:
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 {
1035found2:
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
1095static 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
1126static 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 */
1206static 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
1465static 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
1551static 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
1622static 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
1630static void flush(AVCodecContext *avctx)
1631{
1632    mp_flush(avctx->priv_data);
1633}
1634
1635#if CONFIG_MP3ADU_DECODER || CONFIG_MP3ADUFLOAT_DECODER
1636static 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 */
1694typedef 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 */
1706static 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 */
1709static 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 */
1721static 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
1732static 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
1744static 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
1806static 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
1816static 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