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FFmpeg/libavcodec/mpegaudiodec_template.c

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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 "libavutil/attributes.h"

  28. #include "libavutil/avassert.h"

  29. #include "libavutil/channel_layout.h"

  30. #include "libavutil/crc.h"

  31. #include "libavutil/float_dsp.h"

  32. #include "libavutil/libm.h"

  33. #include "avcodec.h"

  34. #include "get_bits.h"

  35. #include "internal.h"

  36. #include "mathops.h"

  37. #include "mpegaudiodsp.h"

  38. 

  39. /*

  40.  * TODO:

  41.  *  - test lsf / mpeg25 extensively.

  42.  */

  43. 

  44. #include "mpegaudio.h"

  45. #include "mpegaudiodecheader.h"

  46. 

  47. #define BACKSTEP_SIZE 512

  48. #define EXTRABYTES 24

  49. #define LAST_BUF_SIZE 2 * BACKSTEP_SIZE + EXTRABYTES

  50. 

  51. /* layer 3 "granule" */

  52. typedef struct GranuleDef {

  53.     uint8_t scfsi;

  54.     int part2_3_length;

  55.     int big_values;

  56.     int global_gain;

  57.     int scalefac_compress;

  58.     uint8_t block_type;

  59.     uint8_t switch_point;

  60.     int table_select[3];

  61.     int subblock_gain[3];

  62.     uint8_t scalefac_scale;

  63.     uint8_t count1table_select;

  64.     int region_size[3]; /* number of huffman codes in each region */

  65.     int preflag;

  66.     int short_start, long_end; /* long/short band indexes */

  67.     uint8_t scale_factors[40];

  68.     DECLARE_ALIGNED(16, INTFLOAT, sb_hybrid)[SBLIMIT * 18]; /* 576 samples */

  69. } GranuleDef;

  70. 

  71. typedef struct MPADecodeContext {

  72.     MPA_DECODE_HEADER

  73.     uint8_t last_buf[LAST_BUF_SIZE];

  74.     int last_buf_size;

  75.     int extrasize;

  76.     /* next header (used in free format parsing) */

  77.     uint32_t free_format_next_header;

  78.     GetBitContext gb;

  79.     GetBitContext in_gb;

  80.     DECLARE_ALIGNED(32, MPA_INT, synth_buf)[MPA_MAX_CHANNELS][512 * 2];

  81.     int synth_buf_offset[MPA_MAX_CHANNELS];

  82.     DECLARE_ALIGNED(32, INTFLOAT, sb_samples)[MPA_MAX_CHANNELS][36][SBLIMIT];

  83.     INTFLOAT mdct_buf[MPA_MAX_CHANNELS][SBLIMIT * 18]; /* previous samples, for layer 3 MDCT */

  84.     GranuleDef granules[2][2]; /* Used in Layer 3 */

  85.     int adu_mode; ///< 0 for standard mp3, 1 for adu formatted mp3

  86.     int dither_state;

  87.     int err_recognition;

  88.     AVCodecContext* avctx;

  89.     MPADSPContext mpadsp;

  90.     AVFloatDSPContext *fdsp;

  91.     AVFrame *frame;

  92. } MPADecodeContext;

  93. 

  94. #define HEADER_SIZE 4

  95. 

  96. #include "mpegaudiodata.h"

  97. #include "mpegaudiodectab.h"

  98. 

  99. /* vlc structure for decoding layer 3 huffman tables */

  100. static VLC huff_vlc[16];

  101. static VLC_TYPE huff_vlc_tables[

  102.     0 + 128 + 128 + 128 + 130 + 128 + 154 + 166 +

  103.   142 + 204 + 190 + 170 + 542 + 460 + 662 + 414

  104.   ][2];

  105. static const int huff_vlc_tables_sizes[16] = {

  106.     0,  128,  128,  128,  130,  128,  154,  166,

  107.   142,  204,  190,  170,  542,  460,  662,  414

  108. };

  109. static VLC huff_quad_vlc[2];

  110. static VLC_TYPE  huff_quad_vlc_tables[128+16][2];

  111. static const int huff_quad_vlc_tables_sizes[2] = { 128, 16 };

  112. /* computed from band_size_long */

  113. static uint16_t band_index_long[9][23];

  114. #include "mpegaudio_tablegen.h"

  115. /* intensity stereo coef table */

  116. static INTFLOAT is_table[2][16];

  117. static INTFLOAT is_table_lsf[2][2][16];

  118. static INTFLOAT csa_table[8][4];

  119. 

  120. static int16_t division_tab3[1<<6 ];

  121. static int16_t division_tab5[1<<8 ];

  122. static int16_t division_tab9[1<<11];

  123. 

  124. static int16_t * const division_tabs[4] = {

  125.     division_tab3, division_tab5, NULL, division_tab9

  126. };

  127. 

  128. /* lower 2 bits: modulo 3, higher bits: shift */

  129. static uint16_t scale_factor_modshift[64];

  130. /* [i][j]:  2^(-j/3) * FRAC_ONE * 2^(i+2) / (2^(i+2) - 1) */

  131. static int32_t scale_factor_mult[15][3];

  132. /* mult table for layer 2 group quantization */

  133. 

  134. #define SCALE_GEN(v) \

  135. { FIXR_OLD(1.0 * (v)), FIXR_OLD(0.7937005259 * (v)), FIXR_OLD(0.6299605249 * (v)) }

  136. 

  137. static const int32_t scale_factor_mult2[3][3] = {

  138.     SCALE_GEN(4.0 / 3.0), /* 3 steps */

  139.     SCALE_GEN(4.0 / 5.0), /* 5 steps */

  140.     SCALE_GEN(4.0 / 9.0), /* 9 steps */

  141. };

  142. 

  143. /**

  144.  * Convert region offsets to region sizes and truncate

  145.  * size to big_values.

  146.  */

  147. static void region_offset2size(GranuleDef *g)

  148. {

  149.     int i, k, j = 0;

  150.     g->region_size[2] = 576 / 2;

  151.     for (i = 0; i < 3; i++) {

  152.         k = FFMIN(g->region_size[i], g->big_values);

  153.         g->region_size[i] = k - j;

  154.         j = k;

  155.     }

  156. }

  157. 

  158. static void init_short_region(MPADecodeContext *s, GranuleDef *g)

  159. {

  160.     if (g->block_type == 2) {

  161.         if (s->sample_rate_index != 8)

  162.             g->region_size[0] = (36 / 2);

  163.         else

  164.             g->region_size[0] = (72 / 2);

  165.     } else {

  166.         if (s->sample_rate_index <= 2)

  167.             g->region_size[0] = (36 / 2);

  168.         else if (s->sample_rate_index != 8)

  169.             g->region_size[0] = (54 / 2);

  170.         else

  171.             g->region_size[0] = (108 / 2);

  172.     }

  173.     g->region_size[1] = (576 / 2);

  174. }

  175. 

  176. static void init_long_region(MPADecodeContext *s, GranuleDef *g,

  177.                              int ra1, int ra2)

  178. {

  179.     int l;

  180.     g->region_size[0] = band_index_long[s->sample_rate_index][ra1 + 1] >> 1;

  181.     /* should not overflow */

  182.     l = FFMIN(ra1 + ra2 + 2, 22);

  183.     g->region_size[1] = band_index_long[s->sample_rate_index][      l] >> 1;

  184. }

  185. 

  186. static void compute_band_indexes(MPADecodeContext *s, GranuleDef *g)

  187. {

  188.     if (g->block_type == 2) {

  189.         if (g->switch_point) {

  190.             if(s->sample_rate_index == 8)

  191.                 avpriv_request_sample(s->avctx, "switch point in 8khz");

  192.             /* if switched mode, we handle the 36 first samples as

  193.                 long blocks.  For 8000Hz, we handle the 72 first

  194.                 exponents as long blocks */

  195.             if (s->sample_rate_index <= 2)

  196.                 g->long_end = 8;

  197.             else

  198.                 g->long_end = 6;

  199. 

  200.             g->short_start = 3;

  201.         } else {

  202.             g->long_end    = 0;

  203.             g->short_start = 0;

  204.         }

  205.     } else {

  206.         g->short_start = 13;

  207.         g->long_end    = 22;

  208.     }

  209. }

  210. 

  211. /* layer 1 unscaling */

  212. /* n = number of bits of the mantissa minus 1 */

  213. static inline int l1_unscale(int n, int mant, int scale_factor)

  214. {

  215.     int shift, mod;

  216.     int64_t val;

  217. 

  218.     shift   = scale_factor_modshift[scale_factor];

  219.     mod     = shift & 3;

  220.     shift >>= 2;

  221.     val     = MUL64((int)(mant + (-1U << n) + 1), scale_factor_mult[n-1][mod]);

  222.     shift  += n;

  223.     /* NOTE: at this point, 1 <= shift >= 21 + 15 */

  224.     return (int)((val + (1LL << (shift - 1))) >> shift);

  225. }

  226. 

  227. static inline int l2_unscale_group(int steps, int mant, int scale_factor)

  228. {

  229.     int shift, mod, val;

  230. 

  231.     shift   = scale_factor_modshift[scale_factor];

  232.     mod     = shift & 3;

  233.     shift >>= 2;

  234. 

  235.     val = (mant - (steps >> 1)) * scale_factor_mult2[steps >> 2][mod];

  236.     /* NOTE: at this point, 0 <= shift <= 21 */

  237.     if (shift > 0)

  238.         val = (val + (1 << (shift - 1))) >> shift;

  239.     return val;

  240. }

  241. 

  242. /* compute value^(4/3) * 2^(exponent/4). It normalized to FRAC_BITS */

  243. static inline int l3_unscale(int value, int exponent)

  244. {

  245.     unsigned int m;

  246.     int e;

  247. 

  248.     e  = table_4_3_exp  [4 * value + (exponent & 3)];

  249.     m  = table_4_3_value[4 * value + (exponent & 3)];

  250.     e -= exponent >> 2;

  251. #ifdef DEBUG

  252.     if(e < 1)

  253.         av_log(NULL, AV_LOG_WARNING, "l3_unscale: e is %d\n", e);

  254. #endif

  255.     if (e > (SUINT)31)

  256.         return 0;

  257.     m = (m + ((1U << e)>>1)) >> e;

  258. 

  259.     return m;

  260. }

  261. 

  262. static av_cold void decode_init_static(void)

  263. {

  264.     int i, j, k;

  265.     int offset;

  266. 

  267.     /* scale factors table for layer 1/2 */

  268.     for (i = 0; i < 64; i++) {

  269.         int shift, mod;

  270.         /* 1.0 (i = 3) is normalized to 2 ^ FRAC_BITS */

  271.         shift = i / 3;

  272.         mod   = i % 3;

  273.         scale_factor_modshift[i] = mod | (shift << 2);

  274.     }

  275. 

  276.     /* scale factor multiply for layer 1 */

  277.     for (i = 0; i < 15; i++) {

  278.         int n, norm;

  279.         n = i + 2;

  280.         norm = ((INT64_C(1) << n) * FRAC_ONE) / ((1 << n) - 1);

  281.         scale_factor_mult[i][0] = MULLx(norm, FIXR(1.0          * 2.0), FRAC_BITS);

  282.         scale_factor_mult[i][1] = MULLx(norm, FIXR(0.7937005259 * 2.0), FRAC_BITS);

  283.         scale_factor_mult[i][2] = MULLx(norm, FIXR(0.6299605249 * 2.0), FRAC_BITS);

  284.         ff_dlog(NULL, "%d: norm=%x s=%"PRIx32" %"PRIx32" %"PRIx32"\n", i,

  285.                 (unsigned)norm,

  286.                 scale_factor_mult[i][0],

  287.                 scale_factor_mult[i][1],

  288.                 scale_factor_mult[i][2]);

  289.     }

  290. 

  291.     RENAME(ff_mpa_synth_init)(RENAME(ff_mpa_synth_window));

  292. 

  293.     /* huffman decode tables */

  294.     offset = 0;

  295.     for (i = 1; i < 16; i++) {

  296.         const HuffTable *h = &mpa_huff_tables[i];

  297.         int xsize, x, y;

  298.         uint8_t  tmp_bits [512] = { 0 };

  299.         uint16_t tmp_codes[512] = { 0 };

  300. 

  301.         xsize = h->xsize;

  302. 

  303.         j = 0;

  304.         for (x = 0; x < xsize; x++) {

  305.             for (y = 0; y < xsize; y++) {

  306.                 tmp_bits [(x << 5) | y | ((x&&y)<<4)]= h->bits [j  ];

  307.                 tmp_codes[(x << 5) | y | ((x&&y)<<4)]= h->codes[j++];

  308.             }

  309.         }

  310. 

  311.         /* XXX: fail test */

  312.         huff_vlc[i].table = huff_vlc_tables+offset;

  313.         huff_vlc[i].table_allocated = huff_vlc_tables_sizes[i];

  314.         init_vlc(&huff_vlc[i], 7, 512,

  315.                  tmp_bits, 1, 1, tmp_codes, 2, 2,

  316.                  INIT_VLC_USE_NEW_STATIC);

  317.         offset += huff_vlc_tables_sizes[i];

  318.     }

  319.     av_assert0(offset == FF_ARRAY_ELEMS(huff_vlc_tables));

  320. 

  321.     offset = 0;

  322.     for (i = 0; i < 2; i++) {

  323.         huff_quad_vlc[i].table = huff_quad_vlc_tables+offset;

  324.         huff_quad_vlc[i].table_allocated = huff_quad_vlc_tables_sizes[i];

  325.         init_vlc(&huff_quad_vlc[i], i == 0 ? 7 : 4, 16,

  326.                  mpa_quad_bits[i], 1, 1, mpa_quad_codes[i], 1, 1,

  327.                  INIT_VLC_USE_NEW_STATIC);

  328.         offset += huff_quad_vlc_tables_sizes[i];

  329.     }

  330.     av_assert0(offset == FF_ARRAY_ELEMS(huff_quad_vlc_tables));

  331. 

  332.     for (i = 0; i < 9; i++) {

  333.         k = 0;

  334.         for (j = 0; j < 22; j++) {

  335.             band_index_long[i][j] = k;

  336.             k += band_size_long[i][j];

  337.         }

  338.         band_index_long[i][22] = k;

  339.     }

  340. 

  341.     /* compute n ^ (4/3) and store it in mantissa/exp format */

  342. 

  343.     mpegaudio_tableinit();

  344. 

  345.     for (i = 0; i < 4; i++) {

  346.         if (ff_mpa_quant_bits[i] < 0) {

  347.             for (j = 0; j < (1 << (-ff_mpa_quant_bits[i]+1)); j++) {

  348.                 int val1, val2, val3, steps;

  349.                 int val = j;

  350.                 steps   = ff_mpa_quant_steps[i];

  351.                 val1    = val % steps;

  352.                 val    /= steps;

  353.                 val2    = val % steps;

  354.                 val3    = val / steps;

  355.                 division_tabs[i][j] = val1 + (val2 << 4) + (val3 << 8);

  356.             }

  357.         }

  358.     }

  359. 

  360. 

  361.     for (i = 0; i < 7; i++) {

  362.         float f;

  363.         INTFLOAT v;

  364.         if (i != 6) {

  365.             f = tan((double)i * M_PI / 12.0);

  366.             v = FIXR(f / (1.0 + f));

  367.         } else {

  368.             v = FIXR(1.0);

  369.         }

  370.         is_table[0][    i] = v;

  371.         is_table[1][6 - i] = v;

  372.     }

  373.     /* invalid values */

  374.     for (i = 7; i < 16; i++)

  375.         is_table[0][i] = is_table[1][i] = 0.0;

  376. 

  377.     for (i = 0; i < 16; i++) {

  378.         double f;

  379.         int e, k;

  380. 

  381.         for (j = 0; j < 2; j++) {

  382.             e = -(j + 1) * ((i + 1) >> 1);

  383.             f = exp2(e / 4.0);

  384.             k = i & 1;

  385.             is_table_lsf[j][k ^ 1][i] = FIXR(f);

  386.             is_table_lsf[j][k    ][i] = FIXR(1.0);

  387.             ff_dlog(NULL, "is_table_lsf %d %d: %f %f\n",

  388.                     i, j, (float) is_table_lsf[j][0][i],

  389.                     (float) is_table_lsf[j][1][i]);

  390.         }

  391.     }

  392. 

  393.     for (i = 0; i < 8; i++) {

  394.         double ci, cs, ca;

  395.         ci = ci_table[i];

  396.         cs = 1.0 / sqrt(1.0 + ci * ci);

  397.         ca = cs * ci;

  398. #if !USE_FLOATS

  399.         csa_table[i][0] = FIXHR(cs/4);

  400.         csa_table[i][1] = FIXHR(ca/4);

  401.         csa_table[i][2] = FIXHR(ca/4) + FIXHR(cs/4);

  402.         csa_table[i][3] = FIXHR(ca/4) - FIXHR(cs/4);

  403. #else

  404.         csa_table[i][0] = cs;

  405.         csa_table[i][1] = ca;

  406.         csa_table[i][2] = ca + cs;

  407.         csa_table[i][3] = ca - cs;

  408. #endif

  409.     }

  410. }

  411. 

  412. #if USE_FLOATS

  413. static av_cold int decode_close(AVCodecContext * avctx)

  414. {

  415.     MPADecodeContext *s = avctx->priv_data;

  416.     av_freep(&s->fdsp);

  417. 

  418.     return 0;

  419. }

  420. #endif

  421. 

  422. static av_cold int decode_init(AVCodecContext * avctx)

  423. {

  424.     static int initialized_tables = 0;

  425.     MPADecodeContext *s = avctx->priv_data;

  426. 

  427.     if (!initialized_tables) {

  428.         decode_init_static();

  429.         initialized_tables = 1;

  430.     }

  431. 

  432.     s->avctx = avctx;

  433. 

  434. #if USE_FLOATS

  435.     s->fdsp = avpriv_float_dsp_alloc(avctx->flags & AV_CODEC_FLAG_BITEXACT);

  436.     if (!s->fdsp)

  437.         return AVERROR(ENOMEM);

  438. #endif

  439. 

  440.     ff_mpadsp_init(&s->mpadsp);

  441. 

  442.     if (avctx->request_sample_fmt == OUT_FMT &&

  443.         avctx->codec_id != AV_CODEC_ID_MP3ON4)

  444.         avctx->sample_fmt = OUT_FMT;

  445.     else

  446.         avctx->sample_fmt = OUT_FMT_P;

  447.     s->err_recognition = avctx->err_recognition;

  448. 

  449.     if (avctx->codec_id == AV_CODEC_ID_MP3ADU)

  450.         s->adu_mode = 1;

  451. 

  452.     return 0;

  453. }

  454. 

  455. #define C3 FIXHR(0.86602540378443864676/2)

  456. #define C4 FIXHR(0.70710678118654752439/2) //0.5 / cos(pi*(9)/36)

  457. #define C5 FIXHR(0.51763809020504152469/2) //0.5 / cos(pi*(5)/36)

  458. #define C6 FIXHR(1.93185165257813657349/4) //0.5 / cos(pi*(15)/36)

  459. 

  460. /* 12 points IMDCT. We compute it "by hand" by factorizing obvious

  461.    cases. */

  462. static void imdct12(INTFLOAT *out, SUINTFLOAT *in)

  463. {

  464.     SUINTFLOAT in0, in1, in2, in3, in4, in5, t1, t2;

  465. 

  466.     in0  = in[0*3];

  467.     in1  = in[1*3] + in[0*3];

  468.     in2  = in[2*3] + in[1*3];

  469.     in3  = in[3*3] + in[2*3];

  470.     in4  = in[4*3] + in[3*3];

  471.     in5  = in[5*3] + in[4*3];

  472.     in5 += in3;

  473.     in3 += in1;

  474. 

  475.     in2  = MULH3(in2, C3, 2);

  476.     in3  = MULH3(in3, C3, 4);

  477. 

  478.     t1   = in0 - in4;

  479.     t2   = MULH3(in1 - in5, C4, 2);

  480. 

  481.     out[ 7] =

  482.     out[10] = t1 + t2;

  483.     out[ 1] =

  484.     out[ 4] = t1 - t2;

  485. 

  486.     in0    += SHR(in4, 1);

  487.     in4     = in0 + in2;

  488.     in5    += 2*in1;

  489.     in1     = MULH3(in5 + in3, C5, 1);

  490.     out[ 8] =

  491.     out[ 9] = in4 + in1;

  492.     out[ 2] =

  493.     out[ 3] = in4 - in1;

  494. 

  495.     in0    -= in2;

  496.     in5     = MULH3(in5 - in3, C6, 2);

  497.     out[ 0] =

  498.     out[ 5] = in0 - in5;

  499.     out[ 6] =

  500.     out[11] = in0 + in5;

  501. }

  502. 

  503. /* return the number of decoded frames */

  504. static int mp_decode_layer1(MPADecodeContext *s)

  505. {

  506.     int bound, i, v, n, ch, j, mant;

  507.     uint8_t allocation[MPA_MAX_CHANNELS][SBLIMIT];

  508.     uint8_t scale_factors[MPA_MAX_CHANNELS][SBLIMIT];

  509. 

  510.     if (s->mode == MPA_JSTEREO)

  511.         bound = (s->mode_ext + 1) * 4;

  512.     else

  513.         bound = SBLIMIT;

  514. 

  515.     /* allocation bits */

  516.     for (i = 0; i < bound; i++) {

  517.         for (ch = 0; ch < s->nb_channels; ch++) {

  518.             allocation[ch][i] = get_bits(&s->gb, 4);

  519.         }

  520.     }

  521.     for (i = bound; i < SBLIMIT; i++)

  522.         allocation[0][i] = get_bits(&s->gb, 4);

  523. 

  524.     /* scale factors */

  525.     for (i = 0; i < bound; i++) {

  526.         for (ch = 0; ch < s->nb_channels; ch++) {

  527.             if (allocation[ch][i])

  528.                 scale_factors[ch][i] = get_bits(&s->gb, 6);

  529.         }

  530.     }

  531.     for (i = bound; i < SBLIMIT; i++) {

  532.         if (allocation[0][i]) {

  533.             scale_factors[0][i] = get_bits(&s->gb, 6);

  534.             scale_factors[1][i] = get_bits(&s->gb, 6);

  535.         }

  536.     }

  537. 

  538.     /* compute samples */

  539.     for (j = 0; j < 12; j++) {

  540.         for (i = 0; i < bound; i++) {

  541.             for (ch = 0; ch < s->nb_channels; ch++) {

  542.                 n = allocation[ch][i];

  543.                 if (n) {

  544.                     mant = get_bits(&s->gb, n + 1);

  545.                     v = l1_unscale(n, mant, scale_factors[ch][i]);

  546.                 } else {

  547.                     v = 0;

  548.                 }

  549.                 s->sb_samples[ch][j][i] = v;

  550.             }

  551.         }

  552.         for (i = bound; i < SBLIMIT; i++) {

  553.             n = allocation[0][i];

  554.             if (n) {

  555.                 mant = get_bits(&s->gb, n + 1);

  556.                 v = l1_unscale(n, mant, scale_factors[0][i]);

  557.                 s->sb_samples[0][j][i] = v;

  558.                 v = l1_unscale(n, mant, scale_factors[1][i]);

  559.                 s->sb_samples[1][j][i] = v;

  560.             } else {

  561.                 s->sb_samples[0][j][i] = 0;

  562.                 s->sb_samples[1][j][i] = 0;

  563.             }

  564.         }

  565.     }

  566.     return 12;

  567. }

  568. 

  569. static int mp_decode_layer2(MPADecodeContext *s)

  570. {

  571.     int sblimit; /* number of used subbands */

  572.     const unsigned char *alloc_table;

  573.     int table, bit_alloc_bits, i, j, ch, bound, v;

  574.     unsigned char bit_alloc[MPA_MAX_CHANNELS][SBLIMIT];

  575.     unsigned char scale_code[MPA_MAX_CHANNELS][SBLIMIT];

  576.     unsigned char scale_factors[MPA_MAX_CHANNELS][SBLIMIT][3], *sf;

  577.     int scale, qindex, bits, steps, k, l, m, b;

  578. 

  579.     /* select decoding table */

  580.     table = ff_mpa_l2_select_table(s->bit_rate / 1000, s->nb_channels,

  581.                                    s->sample_rate, s->lsf);

  582.     sblimit     = ff_mpa_sblimit_table[table];

  583.     alloc_table = ff_mpa_alloc_tables[table];

  584. 

  585.     if (s->mode == MPA_JSTEREO)

  586.         bound = (s->mode_ext + 1) * 4;

  587.     else

  588.         bound = sblimit;

  589. 

  590.     ff_dlog(s->avctx, "bound=%d sblimit=%d\n", bound, sblimit);

  591. 

  592.     /* sanity check */

  593.     if (bound > sblimit)

  594.         bound = sblimit;

  595. 

  596.     /* parse bit allocation */

  597.     j = 0;

  598.     for (i = 0; i < bound; i++) {

  599.         bit_alloc_bits = alloc_table[j];

  600.         for (ch = 0; ch < s->nb_channels; ch++)

  601.             bit_alloc[ch][i] = get_bits(&s->gb, bit_alloc_bits);

  602.         j += 1 << bit_alloc_bits;

  603.     }

  604.     for (i = bound; i < sblimit; i++) {

  605.         bit_alloc_bits = alloc_table[j];

  606.         v = get_bits(&s->gb, bit_alloc_bits);

  607.         bit_alloc[0][i] = v;

  608.         bit_alloc[1][i] = v;

  609.         j += 1 << bit_alloc_bits;

  610.     }

  611. 

  612.     /* scale codes */

  613.     for (i = 0; i < sblimit; i++) {

  614.         for (ch = 0; ch < s->nb_channels; ch++) {

  615.             if (bit_alloc[ch][i])

  616.                 scale_code[ch][i] = get_bits(&s->gb, 2);

  617.         }

  618.     }

  619. 

  620.     /* scale factors */

  621.     for (i = 0; i < sblimit; i++) {

  622.         for (ch = 0; ch < s->nb_channels; ch++) {

  623.             if (bit_alloc[ch][i]) {

  624.                 sf = scale_factors[ch][i];

  625.                 switch (scale_code[ch][i]) {

  626.                 default:

  627.                 case 0:

  628.                     sf[0] = get_bits(&s->gb, 6);

  629.                     sf[1] = get_bits(&s->gb, 6);

  630.                     sf[2] = get_bits(&s->gb, 6);

  631.                     break;

  632.                 case 2:

  633.                     sf[0] = get_bits(&s->gb, 6);

  634.                     sf[1] = sf[0];

  635.                     sf[2] = sf[0];

  636.                     break;

  637.                 case 1:

  638.                     sf[0] = get_bits(&s->gb, 6);

  639.                     sf[2] = get_bits(&s->gb, 6);

  640.                     sf[1] = sf[0];

  641.                     break;

  642.                 case 3:

  643.                     sf[0] = get_bits(&s->gb, 6);

  644.                     sf[2] = get_bits(&s->gb, 6);

  645.                     sf[1] = sf[2];

  646.                     break;

  647.                 }

  648.             }

  649.         }

  650.     }

  651. 

  652.     /* samples */

  653.     for (k = 0; k < 3; k++) {

  654.         for (l = 0; l < 12; l += 3) {

  655.             j = 0;

  656.             for (i = 0; i < bound; i++) {

  657.                 bit_alloc_bits = alloc_table[j];

  658.                 for (ch = 0; ch < s->nb_channels; ch++) {

  659.                     b = bit_alloc[ch][i];

  660.                     if (b) {

  661.                         scale = scale_factors[ch][i][k];

  662.                         qindex = alloc_table[j+b];

  663.                         bits = ff_mpa_quant_bits[qindex];

  664.                         if (bits < 0) {

  665.                             int v2;

  666.                             /* 3 values at the same time */

  667.                             v = get_bits(&s->gb, -bits);

  668.                             v2 = division_tabs[qindex][v];

  669.                             steps  = ff_mpa_quant_steps[qindex];

  670. 

  671.                             s->sb_samples[ch][k * 12 + l + 0][i] =

  672.                                 l2_unscale_group(steps,  v2       & 15, scale);

  673.                             s->sb_samples[ch][k * 12 + l + 1][i] =

  674.                                 l2_unscale_group(steps, (v2 >> 4) & 15, scale);

  675.                             s->sb_samples[ch][k * 12 + l + 2][i] =

  676.                                 l2_unscale_group(steps,  v2 >> 8      , scale);

  677.                         } else {

  678.                             for (m = 0; m < 3; m++) {

  679.                                 v = get_bits(&s->gb, bits);

  680.                                 v = l1_unscale(bits - 1, v, scale);

  681.                                 s->sb_samples[ch][k * 12 + l + m][i] = v;

  682.                             }

  683.                         }

  684.                     } else {

  685.                         s->sb_samples[ch][k * 12 + l + 0][i] = 0;

  686.                         s->sb_samples[ch][k * 12 + l + 1][i] = 0;

  687.                         s->sb_samples[ch][k * 12 + l + 2][i] = 0;

  688.                     }

  689.                 }

  690.                 /* next subband in alloc table */

  691.                 j += 1 << bit_alloc_bits;

  692.             }

  693.             /* XXX: find a way to avoid this duplication of code */

  694.             for (i = bound; i < sblimit; i++) {

  695.                 bit_alloc_bits = alloc_table[j];

  696.                 b = bit_alloc[0][i];

  697.                 if (b) {

  698.                     int mant, scale0, scale1;

  699.                     scale0 = scale_factors[0][i][k];

  700.                     scale1 = scale_factors[1][i][k];

  701.                     qindex = alloc_table[j+b];

  702.                     bits = ff_mpa_quant_bits[qindex];

  703.                     if (bits < 0) {

  704.                         /* 3 values at the same time */

  705.                         v = get_bits(&s->gb, -bits);

  706.                         steps = ff_mpa_quant_steps[qindex];

  707.                         mant = v % steps;

  708.                         v = v / steps;

  709.                         s->sb_samples[0][k * 12 + l + 0][i] =

  710.                             l2_unscale_group(steps, mant, scale0);

  711.                         s->sb_samples[1][k * 12 + l + 0][i] =

  712.                             l2_unscale_group(steps, mant, scale1);

  713.                         mant = v % steps;

  714.                         v = v / steps;

  715.                         s->sb_samples[0][k * 12 + l + 1][i] =

  716.                             l2_unscale_group(steps, mant, scale0);

  717.                         s->sb_samples[1][k * 12 + l + 1][i] =

  718.                             l2_unscale_group(steps, mant, scale1);

  719.                         s->sb_samples[0][k * 12 + l + 2][i] =

  720.                             l2_unscale_group(steps, v, scale0);

  721.                         s->sb_samples[1][k * 12 + l + 2][i] =

  722.                             l2_unscale_group(steps, v, scale1);

  723.                     } else {

  724.                         for (m = 0; m < 3; m++) {

  725.                             mant = get_bits(&s->gb, bits);

  726.                             s->sb_samples[0][k * 12 + l + m][i] =

  727.                                 l1_unscale(bits - 1, mant, scale0);

  728.                             s->sb_samples[1][k * 12 + l + m][i] =

  729.                                 l1_unscale(bits - 1, mant, scale1);

  730.                         }

  731.                     }

  732.                 } else {

  733.                     s->sb_samples[0][k * 12 + l + 0][i] = 0;

  734.                     s->sb_samples[0][k * 12 + l + 1][i] = 0;

  735.                     s->sb_samples[0][k * 12 + l + 2][i] = 0;

  736.                     s->sb_samples[1][k * 12 + l + 0][i] = 0;

  737.                     s->sb_samples[1][k * 12 + l + 1][i] = 0;

  738.                     s->sb_samples[1][k * 12 + l + 2][i] = 0;

  739.                 }

  740.                 /* next subband in alloc table */

  741.                 j += 1 << bit_alloc_bits;

  742.             }

  743.             /* fill remaining samples to zero */

  744.             for (i = sblimit; i < SBLIMIT; i++) {

  745.                 for (ch = 0; ch < s->nb_channels; ch++) {

  746.                     s->sb_samples[ch][k * 12 + l + 0][i] = 0;

  747.                     s->sb_samples[ch][k * 12 + l + 1][i] = 0;

  748.                     s->sb_samples[ch][k * 12 + l + 2][i] = 0;

  749.                 }

  750.             }

  751.         }

  752.     }

  753.     return 3 * 12;

  754. }

  755. 

  756. #define SPLIT(dst,sf,n)             \

  757.     if (n == 3) {                   \

  758.         int m = (sf * 171) >> 9;    \

  759.         dst   = sf - 3 * m;         \

  760.         sf    = m;                  \

  761.     } else if (n == 4) {            \

  762.         dst  = sf & 3;              \

  763.         sf >>= 2;                   \

  764.     } else if (n == 5) {            \

  765.         int m = (sf * 205) >> 10;   \

  766.         dst   = sf - 5 * m;         \

  767.         sf    = m;                  \

  768.     } else if (n == 6) {            \

  769.         int m = (sf * 171) >> 10;   \

  770.         dst   = sf - 6 * m;         \

  771.         sf    = m;                  \

  772.     } else {                        \

  773.         dst = 0;                    \

  774.     }

  775. 

  776. static av_always_inline void lsf_sf_expand(int *slen, int sf, int n1, int n2,

  777.                                            int n3)

  778. {

  779.     SPLIT(slen[3], sf, n3)

  780.     SPLIT(slen[2], sf, n2)

  781.     SPLIT(slen[1], sf, n1)

  782.     slen[0] = sf;

  783. }

  784. 

  785. static void exponents_from_scale_factors(MPADecodeContext *s, GranuleDef *g,

  786.                                          int16_t *exponents)

  787. {

  788.     const uint8_t *bstab, *pretab;

  789.     int len, i, j, k, l, v0, shift, gain, gains[3];

  790.     int16_t *exp_ptr;

  791. 

  792.     exp_ptr = exponents;

  793.     gain    = g->global_gain - 210;

  794.     shift   = g->scalefac_scale + 1;

  795. 

  796.     bstab  = band_size_long[s->sample_rate_index];

  797.     pretab = mpa_pretab[g->preflag];

  798.     for (i = 0; i < g->long_end; i++) {

  799.         v0 = gain - ((g->scale_factors[i] + pretab[i]) << shift) + 400;

  800.         len = bstab[i];

  801.         for (j = len; j > 0; j--)

  802.             *exp_ptr++ = v0;

  803.     }

  804. 

  805.     if (g->short_start < 13) {

  806.         bstab    = band_size_short[s->sample_rate_index];

  807.         gains[0] = gain - (g->subblock_gain[0] << 3);

  808.         gains[1] = gain - (g->subblock_gain[1] << 3);

  809.         gains[2] = gain - (g->subblock_gain[2] << 3);

  810.         k        = g->long_end;

  811.         for (i = g->short_start; i < 13; i++) {

  812.             len = bstab[i];

  813.             for (l = 0; l < 3; l++) {

  814.                 v0 = gains[l] - (g->scale_factors[k++] << shift) + 400;

  815.                 for (j = len; j > 0; j--)

  816.                     *exp_ptr++ = v0;

  817.             }

  818.         }

  819.     }

  820. }

  821. 

  822. static void switch_buffer(MPADecodeContext *s, int *pos, int *end_pos,

  823.                           int *end_pos2)

  824. {

  825.     if (s->in_gb.buffer && *pos >= s->gb.size_in_bits - s->extrasize * 8) {

  826.         s->gb           = s->in_gb;

  827.         s->in_gb.buffer = NULL;

  828.         s->extrasize    = 0;

  829.         av_assert2((get_bits_count(&s->gb) & 7) == 0);

  830.         skip_bits_long(&s->gb, *pos - *end_pos);

  831.         *end_pos2 =

  832.         *end_pos  = *end_pos2 + get_bits_count(&s->gb) - *pos;

  833.         *pos      = get_bits_count(&s->gb);

  834.     }

  835. }

  836. 

  837. /* Following is an optimized code for

  838.             INTFLOAT v = *src

  839.             if(get_bits1(&s->gb))

  840.                 v = -v;

  841.             *dst = v;

  842. */

  843. #if USE_FLOATS

  844. #define READ_FLIP_SIGN(dst,src)                     \

  845.     v = AV_RN32A(src) ^ (get_bits1(&s->gb) << 31);  \

  846.     AV_WN32A(dst, v);

  847. #else

  848. #define READ_FLIP_SIGN(dst,src)     \

  849.     v      = -get_bits1(&s->gb);    \

  850.     *(dst) = (*(src) ^ v) - v;

  851. #endif

  852. 

  853. static int huffman_decode(MPADecodeContext *s, GranuleDef *g,

  854.                           int16_t *exponents, int end_pos2)

  855. {

  856.     int s_index;

  857.     int i;

  858.     int last_pos, bits_left;

  859.     VLC *vlc;

  860.     int end_pos = FFMIN(end_pos2, s->gb.size_in_bits - s->extrasize * 8);

  861. 

  862.     /* low frequencies (called big values) */

  863.     s_index = 0;

  864.     for (i = 0; i < 3; i++) {

  865.         int j, k, l, linbits;

  866.         j = g->region_size[i];

  867.         if (j == 0)

  868.             continue;

  869.         /* select vlc table */

  870.         k       = g->table_select[i];

  871.         l       = mpa_huff_data[k][0];

  872.         linbits = mpa_huff_data[k][1];

  873.         vlc     = &huff_vlc[l];

  874. 

  875.         if (!l) {

  876.             memset(&g->sb_hybrid[s_index], 0, sizeof(*g->sb_hybrid) * 2 * j);

  877.             s_index += 2 * j;

  878.             continue;

  879.         }

  880. 

  881.         /* read huffcode and compute each couple */

  882.         for (; j > 0; j--) {

  883.             int exponent, x, y;

  884.             int v;

  885.             int pos = get_bits_count(&s->gb);

  886. 

  887.             if (pos >= end_pos){

  888.                 switch_buffer(s, &pos, &end_pos, &end_pos2);

  889.                 if (pos >= end_pos)

  890.                     break;

  891.             }

  892.             y = get_vlc2(&s->gb, vlc->table, 7, 3);

  893. 

  894.             if (!y) {

  895.                 g->sb_hybrid[s_index  ] =

  896.                 g->sb_hybrid[s_index+1] = 0;

  897.                 s_index += 2;

  898.                 continue;

  899.             }

  900. 

  901.             exponent= exponents[s_index];

  902. 

  903.             ff_dlog(s->avctx, "region=%d n=%d y=%d exp=%d\n",

  904.                     i, g->region_size[i] - j, y, exponent);

  905.             if (y & 16) {

  906.                 x = y >> 5;

  907.                 y = y & 0x0f;

  908.                 if (x < 15) {

  909.                     READ_FLIP_SIGN(g->sb_hybrid + s_index, RENAME(expval_table)[exponent] + x)

  910.                 } else {

  911.                     x += get_bitsz(&s->gb, linbits);

  912.                     v  = l3_unscale(x, exponent);

  913.                     if (get_bits1(&s->gb))

  914.                         v = -v;

  915.                     g->sb_hybrid[s_index] = v;

  916.                 }

  917.                 if (y < 15) {

  918.                     READ_FLIP_SIGN(g->sb_hybrid + s_index + 1, RENAME(expval_table)[exponent] + y)

  919.                 } else {

  920.                     y += get_bitsz(&s->gb, linbits);

  921.                     v  = l3_unscale(y, exponent);

  922.                     if (get_bits1(&s->gb))

  923.                         v = -v;

  924.                     g->sb_hybrid[s_index+1] = v;

  925.                 }

  926.             } else {

  927.                 x = y >> 5;

  928.                 y = y & 0x0f;

  929.                 x += y;

  930.                 if (x < 15) {

  931.                     READ_FLIP_SIGN(g->sb_hybrid + s_index + !!y, RENAME(expval_table)[exponent] + x)

  932.                 } else {

  933.                     x += get_bitsz(&s->gb, linbits);

  934.                     v  = l3_unscale(x, exponent);

  935.                     if (get_bits1(&s->gb))

  936.                         v = -v;

  937.                     g->sb_hybrid[s_index+!!y] = v;

  938.                 }

  939.                 g->sb_hybrid[s_index + !y] = 0;

  940.             }

  941.             s_index += 2;

  942.         }

  943.     }

  944. 

  945.     /* high frequencies */

  946.     vlc = &huff_quad_vlc[g->count1table_select];

  947.     last_pos = 0;

  948.     while (s_index <= 572) {

  949.         int pos, code;

  950.         pos = get_bits_count(&s->gb);

  951.         if (pos >= end_pos) {

  952.             if (pos > end_pos2 && last_pos) {

  953.                 /* some encoders generate an incorrect size for this

  954.                    part. We must go back into the data */

  955.                 s_index -= 4;

  956.                 skip_bits_long(&s->gb, last_pos - pos);

  957.                 av_log(s->avctx, AV_LOG_INFO, "overread, skip %d enddists: %d %d\n", last_pos - pos, end_pos-pos, end_pos2-pos);

  958.                 if(s->err_recognition & (AV_EF_BITSTREAM|AV_EF_COMPLIANT))

  959.                     s_index=0;

  960.                 break;

  961.             }

  962.             switch_buffer(s, &pos, &end_pos, &end_pos2);

  963.             if (pos >= end_pos)

  964.                 break;

  965.         }

  966.         last_pos = pos;

  967. 

  968.         code = get_vlc2(&s->gb, vlc->table, vlc->bits, 1);

  969.         ff_dlog(s->avctx, "t=%d code=%d\n", g->count1table_select, code);

  970.         g->sb_hybrid[s_index+0] =

  971.         g->sb_hybrid[s_index+1] =

  972.         g->sb_hybrid[s_index+2] =

  973.         g->sb_hybrid[s_index+3] = 0;

  974.         while (code) {

  975.             static const int idxtab[16] = { 3,3,2,2,1,1,1,1,0,0,0,0,0,0,0,0 };

  976.             int v;

  977.             int pos = s_index + idxtab[code];

  978.             code   ^= 8 >> idxtab[code];

  979.             READ_FLIP_SIGN(g->sb_hybrid + pos, RENAME(exp_table)+exponents[pos])

  980.         }

  981.         s_index += 4;

  982.     }

  983.     /* skip extension bits */

  984.     bits_left = end_pos2 - get_bits_count(&s->gb);

  985.     if (bits_left < 0 && (s->err_recognition & (AV_EF_BUFFER|AV_EF_COMPLIANT))) {

  986.         av_log(s->avctx, AV_LOG_ERROR, "bits_left=%d\n", bits_left);

  987.         s_index=0;

  988.     } else if (bits_left > 0 && (s->err_recognition & (AV_EF_BUFFER|AV_EF_AGGRESSIVE))) {

  989.         av_log(s->avctx, AV_LOG_ERROR, "bits_left=%d\n", bits_left);

  990.         s_index = 0;

  991.     }

  992.     memset(&g->sb_hybrid[s_index], 0, sizeof(*g->sb_hybrid) * (576 - s_index));

  993.     skip_bits_long(&s->gb, bits_left);

  994. 

  995.     i = get_bits_count(&s->gb);

  996.     switch_buffer(s, &i, &end_pos, &end_pos2);

  997. 

  998.     return 0;

  999. }

  1000. 

  1001. /* Reorder short blocks from bitstream order to interleaved order. It

  1002.    would be faster to do it in parsing, but the code would be far more

  1003.    complicated */

  1004. static void reorder_block(MPADecodeContext *s, GranuleDef *g)

  1005. {

  1006.     int i, j, len;

  1007.     INTFLOAT *ptr, *dst, *ptr1;

  1008.     INTFLOAT tmp[576];

  1009. 

  1010.     if (g->block_type != 2)

  1011.         return;

  1012. 

  1013.     if (g->switch_point) {

  1014.         if (s->sample_rate_index != 8)

  1015.             ptr = g->sb_hybrid + 36;

  1016.         else

  1017.             ptr = g->sb_hybrid + 72;

  1018.     } else {

  1019.         ptr = g->sb_hybrid;

  1020.     }

  1021. 

  1022.     for (i = g->short_start; i < 13; i++) {

  1023.         len  = band_size_short[s->sample_rate_index][i];

  1024.         ptr1 = ptr;

  1025.         dst  = tmp;

  1026.         for (j = len; j > 0; j--) {

  1027.             *dst++ = ptr[0*len];

  1028.             *dst++ = ptr[1*len];

  1029.             *dst++ = ptr[2*len];

  1030.             ptr++;

  1031.         }

  1032.         ptr += 2 * len;

  1033.         memcpy(ptr1, tmp, len * 3 * sizeof(*ptr1));

  1034.     }

  1035. }

  1036. 

  1037. #define ISQRT2 FIXR(0.70710678118654752440)

  1038. 

  1039. static void compute_stereo(MPADecodeContext *s, GranuleDef *g0, GranuleDef *g1)

  1040. {

  1041.     int i, j, k, l;

  1042.     int sf_max, sf, len, non_zero_found;

  1043.     INTFLOAT (*is_tab)[16], *tab0, *tab1, v1, v2;

  1044.     SUINTFLOAT tmp0, tmp1;

  1045.     int non_zero_found_short[3];

  1046. 

  1047.     /* intensity stereo */

  1048.     if (s->mode_ext & MODE_EXT_I_STEREO) {

  1049.         if (!s->lsf) {

  1050.             is_tab = is_table;

  1051.             sf_max = 7;

  1052.         } else {

  1053.             is_tab = is_table_lsf[g1->scalefac_compress & 1];

  1054.             sf_max = 16;

  1055.         }

  1056. 

  1057.         tab0 = g0->sb_hybrid + 576;

  1058.         tab1 = g1->sb_hybrid + 576;

  1059. 

  1060.         non_zero_found_short[0] = 0;

  1061.         non_zero_found_short[1] = 0;

  1062.         non_zero_found_short[2] = 0;

  1063.         k = (13 - g1->short_start) * 3 + g1->long_end - 3;

  1064.         for (i = 12; i >= g1->short_start; i--) {

  1065.             /* for last band, use previous scale factor */

  1066.             if (i != 11)

  1067.                 k -= 3;

  1068.             len = band_size_short[s->sample_rate_index][i];

  1069.             for (l = 2; l >= 0; l--) {

  1070.                 tab0 -= len;

  1071.                 tab1 -= len;

  1072.                 if (!non_zero_found_short[l]) {

  1073.                     /* test if non zero band. if so, stop doing i-stereo */

  1074.                     for (j = 0; j < len; j++) {

  1075.                         if (tab1[j] != 0) {

  1076.                             non_zero_found_short[l] = 1;

  1077.                             goto found1;

  1078.                         }

  1079.                     }

  1080.                     sf = g1->scale_factors[k + l];

  1081.                     if (sf >= sf_max)

  1082.                         goto found1;

  1083. 

  1084.                     v1 = is_tab[0][sf];

  1085.                     v2 = is_tab[1][sf];

  1086.                     for (j = 0; j < len; j++) {

  1087.                         tmp0    = tab0[j];

  1088.                         tab0[j] = MULLx(tmp0, v1, FRAC_BITS);

  1089.                         tab1[j] = MULLx(tmp0, v2, FRAC_BITS);

  1090.                     }

  1091.                 } else {

  1092. found1:

  1093.                     if (s->mode_ext & MODE_EXT_MS_STEREO) {

  1094.                         /* lower part of the spectrum : do ms stereo

  1095.                            if enabled */

  1096.                         for (j = 0; j < len; j++) {

  1097.                             tmp0    = tab0[j];

  1098.                             tmp1    = tab1[j];

  1099.                             tab0[j] = MULLx(tmp0 + tmp1, ISQRT2, FRAC_BITS);

  1100.                             tab1[j] = MULLx(tmp0 - tmp1, ISQRT2, FRAC_BITS);

  1101.                         }

  1102.                     }

  1103.                 }

  1104.             }

  1105.         }

  1106. 

  1107.         non_zero_found = non_zero_found_short[0] |

  1108.                          non_zero_found_short[1] |

  1109.                          non_zero_found_short[2];

  1110. 

  1111.         for (i = g1->long_end - 1;i >= 0;i--) {

  1112.             len   = band_size_long[s->sample_rate_index][i];

  1113.             tab0 -= len;

  1114.             tab1 -= len;

  1115.             /* test if non zero band. if so, stop doing i-stereo */

  1116.             if (!non_zero_found) {

  1117.                 for (j = 0; j < len; j++) {

  1118.                     if (tab1[j] != 0) {

  1119.                         non_zero_found = 1;

  1120.                         goto found2;

  1121.                     }

  1122.                 }

  1123.                 /* for last band, use previous scale factor */

  1124.                 k  = (i == 21) ? 20 : i;

  1125.                 sf = g1->scale_factors[k];

  1126.                 if (sf >= sf_max)

  1127.                     goto found2;

  1128.                 v1 = is_tab[0][sf];

  1129.                 v2 = is_tab[1][sf];

  1130.                 for (j = 0; j < len; j++) {

  1131.                     tmp0    = tab0[j];

  1132.                     tab0[j] = MULLx(tmp0, v1, FRAC_BITS);

  1133.                     tab1[j] = MULLx(tmp0, v2, FRAC_BITS);

  1134.                 }

  1135.             } else {

  1136. found2:

  1137.                 if (s->mode_ext & MODE_EXT_MS_STEREO) {

  1138.                     /* lower part of the spectrum : do ms stereo

  1139.                        if enabled */

  1140.                     for (j = 0; j < len; j++) {

  1141.                         tmp0    = tab0[j];

  1142.                         tmp1    = tab1[j];

  1143.                         tab0[j] = MULLx(tmp0 + tmp1, ISQRT2, FRAC_BITS);

  1144.                         tab1[j] = MULLx(tmp0 - tmp1, ISQRT2, FRAC_BITS);

  1145.                     }

  1146.                 }

  1147.             }

  1148.         }

  1149.     } else if (s->mode_ext & MODE_EXT_MS_STEREO) {

  1150.         /* ms stereo ONLY */

  1151.         /* NOTE: the 1/sqrt(2) normalization factor is included in the

  1152.            global gain */

  1153. #if USE_FLOATS

  1154.        s->fdsp->butterflies_float(g0->sb_hybrid, g1->sb_hybrid, 576);

  1155. #else

  1156.         tab0 = g0->sb_hybrid;

  1157.         tab1 = g1->sb_hybrid;

  1158.         for (i = 0; i < 576; i++) {

  1159.             tmp0    = tab0[i];

  1160.             tmp1    = tab1[i];

  1161.             tab0[i] = tmp0 + tmp1;

  1162.             tab1[i] = tmp0 - tmp1;

  1163.         }

  1164. #endif

  1165.     }

  1166. }

  1167. 

  1168. #if USE_FLOATS

  1169. #if HAVE_MIPSFPU

  1170. #   include "mips/compute_antialias_float.h"

  1171. #endif /* HAVE_MIPSFPU */

  1172. #else

  1173. #if HAVE_MIPSDSP

  1174. #   include "mips/compute_antialias_fixed.h"

  1175. #endif /* HAVE_MIPSDSP */

  1176. #endif /* USE_FLOATS */

  1177. 

  1178. #ifndef compute_antialias

  1179. #if USE_FLOATS

  1180. #define AA(j) do {                                                      \

  1181.         float tmp0 = ptr[-1-j];                                         \

  1182.         float tmp1 = ptr[   j];                                         \

  1183.         ptr[-1-j] = tmp0 * csa_table[j][0] - tmp1 * csa_table[j][1];    \

  1184.         ptr[   j] = tmp0 * csa_table[j][1] + tmp1 * csa_table[j][0];    \

  1185.     } while (0)

  1186. #else

  1187. #define AA(j) do {                                              \

  1188.         SUINT tmp0 = ptr[-1-j];                                   \

  1189.         SUINT tmp1 = ptr[   j];                                   \

  1190.         SUINT tmp2 = MULH(tmp0 + tmp1, csa_table[j][0]);          \

  1191.         ptr[-1-j] = 4 * (tmp2 - MULH(tmp1, csa_table[j][2]));   \

  1192.         ptr[   j] = 4 * (tmp2 + MULH(tmp0, csa_table[j][3]));   \

  1193.     } while (0)

  1194. #endif

  1195. 

  1196. static void compute_antialias(MPADecodeContext *s, GranuleDef *g)

  1197. {

  1198.     INTFLOAT *ptr;

  1199.     int n, i;

  1200. 

  1201.     /* we antialias only "long" bands */

  1202.     if (g->block_type == 2) {

  1203.         if (!g->switch_point)

  1204.             return;

  1205.         /* XXX: check this for 8000Hz case */

  1206.         n = 1;

  1207.     } else {

  1208.         n = SBLIMIT - 1;

  1209.     }

  1210. 

  1211.     ptr = g->sb_hybrid + 18;

  1212.     for (i = n; i > 0; i--) {

  1213.         AA(0);

  1214.         AA(1);

  1215.         AA(2);

  1216.         AA(3);

  1217.         AA(4);

  1218.         AA(5);

  1219.         AA(6);

  1220.         AA(7);

  1221. 

  1222.         ptr += 18;

  1223.     }

  1224. }

  1225. #endif /* compute_antialias */

  1226. 

  1227. static void compute_imdct(MPADecodeContext *s, GranuleDef *g,

  1228.                           INTFLOAT *sb_samples, INTFLOAT *mdct_buf)

  1229. {

  1230.     INTFLOAT *win, *out_ptr, *ptr, *buf, *ptr1;

  1231.     INTFLOAT out2[12];

  1232.     int i, j, mdct_long_end, sblimit;

  1233. 

  1234.     /* find last non zero block */

  1235.     ptr  = g->sb_hybrid + 576;

  1236.     ptr1 = g->sb_hybrid + 2 * 18;

  1237.     while (ptr >= ptr1) {

  1238.         int32_t *p;

  1239.         ptr -= 6;

  1240.         p    = (int32_t*)ptr;

  1241.         if (p[0] | p[1] | p[2] | p[3] | p[4] | p[5])

  1242.             break;

  1243.     }

  1244.     sblimit = ((ptr - g->sb_hybrid) / 18) + 1;

  1245. 

  1246.     if (g->block_type == 2) {

  1247.         /* XXX: check for 8000 Hz */

  1248.         if (g->switch_point)

  1249.             mdct_long_end = 2;

  1250.         else

  1251.             mdct_long_end = 0;

  1252.     } else {

  1253.         mdct_long_end = sblimit;

  1254.     }

  1255. 

  1256.     s->mpadsp.RENAME(imdct36_blocks)(sb_samples, mdct_buf, g->sb_hybrid,

  1257.                                      mdct_long_end, g->switch_point,

  1258.                                      g->block_type);

  1259. 

  1260.     buf = mdct_buf + 4*18*(mdct_long_end >> 2) + (mdct_long_end & 3);

  1261.     ptr = g->sb_hybrid + 18 * mdct_long_end;

  1262. 

  1263.     for (j = mdct_long_end; j < sblimit; j++) {

  1264.         /* select frequency inversion */

  1265.         win     = RENAME(ff_mdct_win)[2 + (4  & -(j & 1))];

  1266.         out_ptr = sb_samples + j;

  1267. 

  1268.         for (i = 0; i < 6; i++) {

  1269.             *out_ptr = buf[4*i];

  1270.             out_ptr += SBLIMIT;

  1271.         }

  1272.         imdct12(out2, ptr + 0);

  1273.         for (i = 0; i < 6; i++) {

  1274.             *out_ptr     = MULH3(out2[i    ], win[i    ], 1) + buf[4*(i + 6*1)];

  1275.             buf[4*(i + 6*2)] = MULH3(out2[i + 6], win[i + 6], 1);

  1276.             out_ptr += SBLIMIT;

  1277.         }

  1278.         imdct12(out2, ptr + 1);

  1279.         for (i = 0; i < 6; i++) {

  1280.             *out_ptr     = MULH3(out2[i    ], win[i    ], 1) + buf[4*(i + 6*2)];

  1281.             buf[4*(i + 6*0)] = MULH3(out2[i + 6], win[i + 6], 1);

  1282.             out_ptr += SBLIMIT;

  1283.         }

  1284.         imdct12(out2, ptr + 2);

  1285.         for (i = 0; i < 6; i++) {

  1286.             buf[4*(i + 6*0)] = MULH3(out2[i    ], win[i    ], 1) + buf[4*(i + 6*0)];

  1287.             buf[4*(i + 6*1)] = MULH3(out2[i + 6], win[i + 6], 1);

  1288.             buf[4*(i + 6*2)] = 0;

  1289.         }

  1290.         ptr += 18;

  1291.         buf += (j&3) != 3 ? 1 : (4*18-3);

  1292.     }

  1293.     /* zero bands */

  1294.     for (j = sblimit; j < SBLIMIT; j++) {

  1295.         /* overlap */

  1296.         out_ptr = sb_samples + j;

  1297.         for (i = 0; i < 18; i++) {

  1298.             *out_ptr = buf[4*i];

  1299.             buf[4*i]   = 0;

  1300.             out_ptr += SBLIMIT;

  1301.         }

  1302.         buf += (j&3) != 3 ? 1 : (4*18-3);

  1303.     }

  1304. }

  1305. 

  1306. /* main layer3 decoding function */

  1307. static int mp_decode_layer3(MPADecodeContext *s)

  1308. {

  1309.     int nb_granules, main_data_begin;

  1310.     int gr, ch, blocksplit_flag, i, j, k, n, bits_pos;

  1311.     GranuleDef *g;

  1312.     int16_t exponents[576]; //FIXME try INTFLOAT

  1313. 

  1314.     /* read side info */

  1315.     if (s->lsf) {

  1316.         main_data_begin = get_bits(&s->gb, 8);

  1317.         skip_bits(&s->gb, s->nb_channels);

  1318.         nb_granules = 1;

  1319.     } else {

  1320.         main_data_begin = get_bits(&s->gb, 9);

  1321.         if (s->nb_channels == 2)

  1322.             skip_bits(&s->gb, 3);

  1323.         else

  1324.             skip_bits(&s->gb, 5);

  1325.         nb_granules = 2;

  1326.         for (ch = 0; ch < s->nb_channels; ch++) {

  1327.             s->granules[ch][0].scfsi = 0;/* all scale factors are transmitted */

  1328.             s->granules[ch][1].scfsi = get_bits(&s->gb, 4);

  1329.         }

  1330.     }

  1331. 

  1332.     for (gr = 0; gr < nb_granules; gr++) {

  1333.         for (ch = 0; ch < s->nb_channels; ch++) {

  1334.             ff_dlog(s->avctx, "gr=%d ch=%d: side_info\n", gr, ch);

  1335.             g = &s->granules[ch][gr];

  1336.             g->part2_3_length = get_bits(&s->gb, 12);

  1337.             g->big_values     = get_bits(&s->gb,  9);

  1338.             if (g->big_values > 288) {

  1339.                 av_log(s->avctx, AV_LOG_ERROR, "big_values too big\n");

  1340.                 return AVERROR_INVALIDDATA;

  1341.             }

  1342. 

  1343.             g->global_gain = get_bits(&s->gb, 8);

  1344.             /* if MS stereo only is selected, we precompute the

  1345.                1/sqrt(2) renormalization factor */

  1346.             if ((s->mode_ext & (MODE_EXT_MS_STEREO | MODE_EXT_I_STEREO)) ==

  1347.                 MODE_EXT_MS_STEREO)

  1348.                 g->global_gain -= 2;

  1349.             if (s->lsf)

  1350.                 g->scalefac_compress = get_bits(&s->gb, 9);

  1351.             else

  1352.                 g->scalefac_compress = get_bits(&s->gb, 4);

  1353.             blocksplit_flag = get_bits1(&s->gb);

  1354.             if (blocksplit_flag) {

  1355.                 g->block_type = get_bits(&s->gb, 2);

  1356.                 if (g->block_type == 0) {

  1357.                     av_log(s->avctx, AV_LOG_ERROR, "invalid block type\n");

  1358.                     return AVERROR_INVALIDDATA;

  1359.                 }

  1360.                 g->switch_point = get_bits1(&s->gb);

  1361.                 for (i = 0; i < 2; i++)

  1362.                     g->table_select[i] = get_bits(&s->gb, 5);

  1363.                 for (i = 0; i < 3; i++)

  1364.                     g->subblock_gain[i] = get_bits(&s->gb, 3);

  1365.                 init_short_region(s, g);

  1366.             } else {

  1367.                 int region_address1, region_address2;

  1368.                 g->block_type = 0;

  1369.                 g->switch_point = 0;

  1370.                 for (i = 0; i < 3; i++)

  1371.                     g->table_select[i] = get_bits(&s->gb, 5);

  1372.                 /* compute huffman coded region sizes */

  1373.                 region_address1 = get_bits(&s->gb, 4);

  1374.                 region_address2 = get_bits(&s->gb, 3);

  1375.                 ff_dlog(s->avctx, "region1=%d region2=%d\n",

  1376.                         region_address1, region_address2);

  1377.                 init_long_region(s, g, region_address1, region_address2);

  1378.             }

  1379.             region_offset2size(g);

  1380.             compute_band_indexes(s, g);

  1381. 

  1382.             g->preflag = 0;

  1383.             if (!s->lsf)

  1384.                 g->preflag = get_bits1(&s->gb);

  1385.             g->scalefac_scale     = get_bits1(&s->gb);

  1386.             g->count1table_select = get_bits1(&s->gb);

  1387.             ff_dlog(s->avctx, "block_type=%d switch_point=%d\n",

  1388.                     g->block_type, g->switch_point);

  1389.         }

  1390.     }

  1391. 

  1392.     if (!s->adu_mode) {

  1393.         int skip;

  1394.         const uint8_t *ptr = s->gb.buffer + (get_bits_count(&s->gb)>>3);

  1395.         s->extrasize = av_clip((get_bits_left(&s->gb) >> 3) - s->extrasize, 0,

  1396.                                FFMAX(0, LAST_BUF_SIZE - s->last_buf_size));

  1397.         av_assert1((get_bits_count(&s->gb) & 7) == 0);

  1398.         /* now we get bits from the main_data_begin offset */

  1399.         ff_dlog(s->avctx, "seekback:%d, lastbuf:%d\n",

  1400.                 main_data_begin, s->last_buf_size);

  1401. 

  1402.         memcpy(s->last_buf + s->last_buf_size, ptr, s->extrasize);

  1403.         s->in_gb = s->gb;

  1404.         init_get_bits(&s->gb, s->last_buf, (s->last_buf_size + s->extrasize) * 8);

  1405.         s->last_buf_size <<= 3;

  1406.         for (gr = 0; gr < nb_granules && (s->last_buf_size >> 3) < main_data_begin; gr++) {

  1407.             for (ch = 0; ch < s->nb_channels; ch++) {

  1408.                 g = &s->granules[ch][gr];

  1409.                 s->last_buf_size += g->part2_3_length;

  1410.                 memset(g->sb_hybrid, 0, sizeof(g->sb_hybrid));

  1411.                 compute_imdct(s, g, &s->sb_samples[ch][18 * gr][0], s->mdct_buf[ch]);

  1412.             }

  1413.         }

  1414.         skip = s->last_buf_size - 8 * main_data_begin;

  1415.         if (skip >= s->gb.size_in_bits - s->extrasize * 8 && s->in_gb.buffer) {

  1416.             skip_bits_long(&s->in_gb, skip - s->gb.size_in_bits + s->extrasize * 8);

  1417.             s->gb           = s->in_gb;

  1418.             s->in_gb.buffer = NULL;

  1419.             s->extrasize    = 0;

  1420.         } else {

  1421.             skip_bits_long(&s->gb, skip);

  1422.         }

  1423.     } else {

  1424.         gr = 0;

  1425.         s->extrasize = 0;

  1426.     }

  1427. 

  1428.     for (; gr < nb_granules; gr++) {

  1429.         for (ch = 0; ch < s->nb_channels; ch++) {

  1430.             g = &s->granules[ch][gr];

  1431.             bits_pos = get_bits_count(&s->gb);

  1432. 

  1433.             if (!s->lsf) {

  1434.                 uint8_t *sc;

  1435.                 int slen, slen1, slen2;

  1436. 

  1437.                 /* MPEG-1 scale factors */

  1438.                 slen1 = slen_table[0][g->scalefac_compress];

  1439.                 slen2 = slen_table[1][g->scalefac_compress];

  1440.                 ff_dlog(s->avctx, "slen1=%d slen2=%d\n", slen1, slen2);

  1441.                 if (g->block_type == 2) {

  1442.                     n = g->switch_point ? 17 : 18;

  1443.                     j = 0;

  1444.                     if (slen1) {

  1445.                         for (i = 0; i < n; i++)

  1446.                             g->scale_factors[j++] = get_bits(&s->gb, slen1);

  1447.                     } else {

  1448.                         for (i = 0; i < n; i++)

  1449.                             g->scale_factors[j++] = 0;

  1450.                     }

  1451.                     if (slen2) {

  1452.                         for (i = 0; i < 18; i++)

  1453.                             g->scale_factors[j++] = get_bits(&s->gb, slen2);

  1454.                         for (i = 0; i < 3; i++)

  1455.                             g->scale_factors[j++] = 0;

  1456.                     } else {

  1457.                         for (i = 0; i < 21; i++)

  1458.                             g->scale_factors[j++] = 0;

  1459.                     }

  1460.                 } else {

  1461.                     sc = s->granules[ch][0].scale_factors;

  1462.                     j = 0;

  1463.                     for (k = 0; k < 4; k++) {

  1464.                         n = k == 0 ? 6 : 5;

  1465.                         if ((g->scfsi & (0x8 >> k)) == 0) {

  1466.                             slen = (k < 2) ? slen1 : slen2;

  1467.                             if (slen) {

  1468.                                 for (i = 0; i < n; i++)

  1469.                                     g->scale_factors[j++] = get_bits(&s->gb, slen);

  1470.                             } else {

  1471.                                 for (i = 0; i < n; i++)

  1472.                                     g->scale_factors[j++] = 0;

  1473.                             }

  1474.                         } else {

  1475.                             /* simply copy from last granule */

  1476.                             for (i = 0; i < n; i++) {

  1477.                                 g->scale_factors[j] = sc[j];

  1478.                                 j++;

  1479.                             }

  1480.                         }

  1481.                     }

  1482.                     g->scale_factors[j++] = 0;

  1483.                 }

  1484.             } else {

  1485.                 int tindex, tindex2, slen[4], sl, sf;

  1486. 

  1487.                 /* LSF scale factors */

  1488.                 if (g->block_type == 2)

  1489.                     tindex = g->switch_point ? 2 : 1;

  1490.                 else

  1491.                     tindex = 0;

  1492. 

  1493.                 sf = g->scalefac_compress;

  1494.                 if ((s->mode_ext & MODE_EXT_I_STEREO) && ch == 1) {

  1495.                     /* intensity stereo case */

  1496.                     sf >>= 1;

  1497.                     if (sf < 180) {

  1498.                         lsf_sf_expand(slen, sf, 6, 6, 0);

  1499.                         tindex2 = 3;

  1500.                     } else if (sf < 244) {

  1501.                         lsf_sf_expand(slen, sf - 180, 4, 4, 0);

  1502.                         tindex2 = 4;

  1503.                     } else {

  1504.                         lsf_sf_expand(slen, sf - 244, 3, 0, 0);

  1505.                         tindex2 = 5;

  1506.                     }

  1507.                 } else {

  1508.                     /* normal case */

  1509.                     if (sf < 400) {

  1510.                         lsf_sf_expand(slen, sf, 5, 4, 4);

  1511.                         tindex2 = 0;

  1512.                     } else if (sf < 500) {

  1513.                         lsf_sf_expand(slen, sf - 400, 5, 4, 0);

  1514.                         tindex2 = 1;

  1515.                     } else {

  1516.                         lsf_sf_expand(slen, sf - 500, 3, 0, 0);

  1517.                         tindex2 = 2;

  1518.                         g->preflag = 1;

  1519.                     }

  1520.                 }

  1521. 

  1522.                 j = 0;

  1523.                 for (k = 0; k < 4; k++) {

  1524.                     n  = lsf_nsf_table[tindex2][tindex][k];

  1525.                     sl = slen[k];

  1526.                     if (sl) {

  1527.                         for (i = 0; i < n; i++)

  1528.                             g->scale_factors[j++] = get_bits(&s->gb, sl);

  1529.                     } else {

  1530.                         for (i = 0; i < n; i++)

  1531.                             g->scale_factors[j++] = 0;

  1532.                     }

  1533.                 }

  1534.                 /* XXX: should compute exact size */

  1535.                 for (; j < 40; j++)

  1536.                     g->scale_factors[j] = 0;

  1537.             }

  1538. 

  1539.             exponents_from_scale_factors(s, g, exponents);

  1540. 

  1541.             /* read Huffman coded residue */

  1542.             huffman_decode(s, g, exponents, bits_pos + g->part2_3_length);

  1543.         } /* ch */

  1544. 

  1545.         if (s->mode == MPA_JSTEREO)

  1546.             compute_stereo(s, &s->granules[0][gr], &s->granules[1][gr]);

  1547. 

  1548.         for (ch = 0; ch < s->nb_channels; ch++) {

  1549.             g = &s->granules[ch][gr];

  1550. 

  1551.             reorder_block(s, g);

  1552.             compute_antialias(s, g);

  1553.             compute_imdct(s, g, &s->sb_samples[ch][18 * gr][0], s->mdct_buf[ch]);

  1554.         }

  1555.     } /* gr */

  1556.     if (get_bits_count(&s->gb) < 0)

  1557.         skip_bits_long(&s->gb, -get_bits_count(&s->gb));

  1558.     return nb_granules * 18;

  1559. }

  1560. 

  1561. static int mp_decode_frame(MPADecodeContext *s, OUT_INT **samples,

  1562.                            const uint8_t *buf, int buf_size)

  1563. {

  1564.     int i, nb_frames, ch, ret;

  1565.     OUT_INT *samples_ptr;

  1566. 

  1567.     init_get_bits(&s->gb, buf + HEADER_SIZE, (buf_size - HEADER_SIZE) * 8);

  1568. 

  1569.     if (s->error_protection) {

  1570.         uint16_t crc = get_bits(&s->gb, 16);

  1571.         if (s->err_recognition & AV_EF_CRCCHECK) {

  1572.             const int sec_len = s->lsf ? ((s->nb_channels == 1) ? 9  : 17) :

  1573.                                          ((s->nb_channels == 1) ? 17 : 32);

  1574.             const AVCRC *crc_tab = av_crc_get_table(AV_CRC_16_ANSI);

  1575.             uint32_t crc_cal = av_crc(crc_tab, UINT16_MAX, &buf[2], 2);

  1576.             crc_cal = av_crc(crc_tab, crc_cal, &buf[6], sec_len);

  1577. 

  1578.             if (av_bswap16(crc) ^ crc_cal) {

  1579.                 av_log(s->avctx, AV_LOG_ERROR, "CRC mismatch!\n");

  1580.                 if (s->err_recognition & AV_EF_EXPLODE)

  1581.                     return AVERROR_INVALIDDATA;

  1582.             }

  1583.         }

  1584.     }

  1585. 

  1586.     switch(s->layer) {

  1587.     case 1:

  1588.         s->avctx->frame_size = 384;

  1589.         nb_frames = mp_decode_layer1(s);

  1590.         break;

  1591.     case 2:

  1592.         s->avctx->frame_size = 1152;

  1593.         nb_frames = mp_decode_layer2(s);

  1594.         break;

  1595.     case 3:

  1596.         s->avctx->frame_size = s->lsf ? 576 : 1152;

  1597.     default:

  1598.         nb_frames = mp_decode_layer3(s);

  1599. 

  1600.         s->last_buf_size=0;

  1601.         if (s->in_gb.buffer) {

  1602.             align_get_bits(&s->gb);

  1603.             i = (get_bits_left(&s->gb) >> 3) - s->extrasize;

  1604.             if (i >= 0 && i <= BACKSTEP_SIZE) {

  1605.                 memmove(s->last_buf, s->gb.buffer + (get_bits_count(&s->gb)>>3), i);

  1606.                 s->last_buf_size=i;

  1607.             } else

  1608.                 av_log(s->avctx, AV_LOG_ERROR, "invalid old backstep %d\n", i);

  1609.             s->gb           = s->in_gb;

  1610.             s->in_gb.buffer = NULL;

  1611.             s->extrasize    = 0;

  1612.         }

  1613. 

  1614.         align_get_bits(&s->gb);

  1615.         av_assert1((get_bits_count(&s->gb) & 7) == 0);

  1616.         i = (get_bits_left(&s->gb) >> 3) - s->extrasize;

  1617.         if (i < 0 || i > BACKSTEP_SIZE || nb_frames < 0) {

  1618.             if (i < 0)

  1619.                 av_log(s->avctx, AV_LOG_ERROR, "invalid new backstep %d\n", i);

  1620.             i = FFMIN(BACKSTEP_SIZE, buf_size - HEADER_SIZE);

  1621.         }

  1622.         av_assert1(i <= buf_size - HEADER_SIZE && i >= 0);

  1623.         memcpy(s->last_buf + s->last_buf_size, s->gb.buffer + buf_size - HEADER_SIZE - i, i);

  1624.         s->last_buf_size += i;

  1625.     }

  1626. 

  1627.     if(nb_frames < 0)

  1628.         return nb_frames;

  1629. 

  1630.     /* get output buffer */

  1631.     if (!samples) {

  1632.         av_assert0(s->frame);

  1633.         s->frame->nb_samples = s->avctx->frame_size;

  1634.         if ((ret = ff_get_buffer(s->avctx, s->frame, 0)) < 0)

  1635.             return ret;

  1636.         samples = (OUT_INT **)s->frame->extended_data;

  1637.     }

  1638. 

  1639.     /* apply the synthesis filter */

  1640.     for (ch = 0; ch < s->nb_channels; ch++) {

  1641.         int sample_stride;

  1642.         if (s->avctx->sample_fmt == OUT_FMT_P) {

  1643.             samples_ptr   = samples[ch];

  1644.             sample_stride = 1;

  1645.         } else {

  1646.             samples_ptr   = samples[0] + ch;

  1647.             sample_stride = s->nb_channels;

  1648.         }

  1649.         for (i = 0; i < nb_frames; i++) {

  1650.             RENAME(ff_mpa_synth_filter)(&s->mpadsp, s->synth_buf[ch],

  1651.                                         &(s->synth_buf_offset[ch]),

  1652.                                         RENAME(ff_mpa_synth_window),

  1653.                                         &s->dither_state, samples_ptr,

  1654.                                         sample_stride, s->sb_samples[ch][i]);

  1655.             samples_ptr += 32 * sample_stride;

  1656.         }

  1657.     }

  1658. 

  1659.     return nb_frames * 32 * sizeof(OUT_INT) * s->nb_channels;

  1660. }

  1661. 

  1662. static int decode_frame(AVCodecContext * avctx, void *data, int *got_frame_ptr,

  1663.                         AVPacket *avpkt)

  1664. {

  1665.     const uint8_t *buf  = avpkt->data;

  1666.     int buf_size        = avpkt->size;

  1667.     MPADecodeContext *s = avctx->priv_data;

  1668.     uint32_t header;

  1669.     int ret;

  1670. 

  1671.     int skipped = 0;

  1672.     while(buf_size && !*buf){

  1673.         buf++;

  1674.         buf_size--;

  1675.         skipped++;

  1676.     }

  1677. 

  1678.     if (buf_size < HEADER_SIZE)

  1679.         return AVERROR_INVALIDDATA;

  1680. 

  1681.     header = AV_RB32(buf);

  1682.     if (header>>8 == AV_RB32("TAG")>>8) {

  1683.         av_log(avctx, AV_LOG_DEBUG, "discarding ID3 tag\n");

  1684.         return buf_size + skipped;

  1685.     }

  1686.     ret = avpriv_mpegaudio_decode_header((MPADecodeHeader *)s, header);

  1687.     if (ret < 0) {

  1688.         av_log(avctx, AV_LOG_ERROR, "Header missing\n");

  1689.         return AVERROR_INVALIDDATA;

  1690.     } else if (ret == 1) {

  1691.         /* free format: prepare to compute frame size */

  1692.         s->frame_size = -1;

  1693.         return AVERROR_INVALIDDATA;

  1694.     }

  1695.     /* update codec info */

  1696.     avctx->channels       = s->nb_channels;

  1697.     avctx->channel_layout = s->nb_channels == 1 ? AV_CH_LAYOUT_MONO : AV_CH_LAYOUT_STEREO;

  1698.     if (!avctx->bit_rate)

  1699.         avctx->bit_rate = s->bit_rate;

  1700. 

  1701.     if (s->frame_size <= 0) {

  1702.         av_log(avctx, AV_LOG_ERROR, "incomplete frame\n");

  1703.         return AVERROR_INVALIDDATA;

  1704.     } else if (s->frame_size < buf_size) {

  1705.         av_log(avctx, AV_LOG_DEBUG, "incorrect frame size - multiple frames in buffer?\n");

  1706.         buf_size= s->frame_size;

  1707.     }

  1708. 

  1709.     s->frame = data;

  1710. 

  1711.     ret = mp_decode_frame(s, NULL, buf, buf_size);

  1712.     if (ret >= 0) {

  1713.         s->frame->nb_samples = avctx->frame_size;

  1714.         *got_frame_ptr       = 1;

  1715.         avctx->sample_rate   = s->sample_rate;

  1716.         //FIXME maybe move the other codec info stuff from above here too

  1717.     } else {

  1718.         av_log(avctx, AV_LOG_ERROR, "Error while decoding MPEG audio frame.\n");

  1719.         /* Only return an error if the bad frame makes up the whole packet or

  1720.          * the error is related to buffer management.

  1721.          * If there is more data in the packet, just consume the bad frame

  1722.          * instead of returning an error, which would discard the whole

  1723.          * packet. */

  1724.         *got_frame_ptr = 0;

  1725.         if (buf_size == avpkt->size || ret != AVERROR_INVALIDDATA)

  1726.             return ret;

  1727.     }

  1728.     s->frame_size = 0;

  1729.     return buf_size + skipped;

  1730. }

  1731. 

  1732. static void mp_flush(MPADecodeContext *ctx)

  1733. {

  1734.     memset(ctx->synth_buf, 0, sizeof(ctx->synth_buf));

  1735.     memset(ctx->mdct_buf, 0, sizeof(ctx->mdct_buf));

  1736.     ctx->last_buf_size = 0;

  1737.     ctx->dither_state = 0;

  1738. }

  1739. 

  1740. static void flush(AVCodecContext *avctx)

  1741. {

  1742.     mp_flush(avctx->priv_data);

  1743. }

  1744. 

  1745. #if CONFIG_MP3ADU_DECODER || CONFIG_MP3ADUFLOAT_DECODER

  1746. static int decode_frame_adu(AVCodecContext *avctx, void *data,

  1747.                             int *got_frame_ptr, AVPacket *avpkt)

  1748. {

  1749.     const uint8_t *buf  = avpkt->data;

  1750.     int buf_size        = avpkt->size;

  1751.     MPADecodeContext *s = avctx->priv_data;

  1752.     uint32_t header;

  1753.     int len, ret;

  1754.     int av_unused out_size;

  1755. 

  1756.     len = buf_size;

  1757. 

  1758.     // Discard too short frames

  1759.     if (buf_size < HEADER_SIZE) {

  1760.         av_log(avctx, AV_LOG_ERROR, "Packet is too small\n");

  1761.         return AVERROR_INVALIDDATA;

  1762.     }

  1763. 

  1764. 

  1765.     if (len > MPA_MAX_CODED_FRAME_SIZE)

  1766.         len = MPA_MAX_CODED_FRAME_SIZE;

  1767. 

  1768.     // Get header and restore sync word

  1769.     header = AV_RB32(buf) | 0xffe00000;

  1770. 

  1771.     ret = avpriv_mpegaudio_decode_header((MPADecodeHeader *)s, header);

  1772.     if (ret < 0) {

  1773.         av_log(avctx, AV_LOG_ERROR, "Invalid frame header\n");

  1774.         return ret;

  1775.     }

  1776.     /* update codec info */

  1777.     avctx->sample_rate = s->sample_rate;

  1778.     avctx->channels    = s->nb_channels;

  1779.     avctx->channel_layout = s->nb_channels == 1 ? AV_CH_LAYOUT_MONO : AV_CH_LAYOUT_STEREO;

  1780.     if (!avctx->bit_rate)

  1781.         avctx->bit_rate = s->bit_rate;

  1782. 

  1783.     s->frame_size = len;

  1784. 

  1785.     s->frame = data;

  1786. 

  1787.     ret = mp_decode_frame(s, NULL, buf, buf_size);

  1788.     if (ret < 0) {

  1789.         av_log(avctx, AV_LOG_ERROR, "Error while decoding MPEG audio frame.\n");

  1790.         return ret;

  1791.     }

  1792. 

  1793.     *got_frame_ptr = 1;

  1794. 

  1795.     return buf_size;

  1796. }

  1797. #endif /* CONFIG_MP3ADU_DECODER || CONFIG_MP3ADUFLOAT_DECODER */

  1798. 

  1799. #if CONFIG_MP3ON4_DECODER || CONFIG_MP3ON4FLOAT_DECODER

  1800. 

  1801. /**

  1802.  * Context for MP3On4 decoder

  1803.  */

  1804. typedef struct MP3On4DecodeContext {

  1805.     int frames;                     ///< number of mp3 frames per block (number of mp3 decoder instances)

  1806.     int syncword;                   ///< syncword patch

  1807.     const uint8_t *coff;            ///< channel offsets in output buffer

  1808.     MPADecodeContext *mp3decctx[5]; ///< MPADecodeContext for every decoder instance

  1809. } MP3On4DecodeContext;

  1810. 

  1811. #include "mpeg4audio.h"

  1812. 

  1813. /* Next 3 arrays are indexed by channel config number (passed via codecdata) */

  1814. 

  1815. /* number of mp3 decoder instances */

  1816. static const uint8_t mp3Frames[8] = { 0, 1, 1, 2, 3, 3, 4, 5 };

  1817. 

  1818. /* offsets into output buffer, assume output order is FL FR C LFE BL BR SL SR */

  1819. static const uint8_t chan_offset[8][5] = {

  1820.     { 0             },

  1821.     { 0             },  // C

  1822.     { 0             },  // FLR

  1823.     { 2, 0          },  // C FLR

  1824.     { 2, 0, 3       },  // C FLR BS

  1825.     { 2, 0, 3       },  // C FLR BLRS

  1826.     { 2, 0, 4, 3    },  // C FLR BLRS LFE

  1827.     { 2, 0, 6, 4, 3 },  // C FLR BLRS BLR LFE

  1828. };

  1829. 

  1830. /* mp3on4 channel layouts */

  1831. static const int16_t chan_layout[8] = {

  1832.     0,

  1833.     AV_CH_LAYOUT_MONO,

  1834.     AV_CH_LAYOUT_STEREO,

  1835.     AV_CH_LAYOUT_SURROUND,

  1836.     AV_CH_LAYOUT_4POINT0,

  1837.     AV_CH_LAYOUT_5POINT0,

  1838.     AV_CH_LAYOUT_5POINT1,

  1839.     AV_CH_LAYOUT_7POINT1

  1840. };

  1841. 

  1842. static av_cold int decode_close_mp3on4(AVCodecContext * avctx)

  1843. {

  1844.     MP3On4DecodeContext *s = avctx->priv_data;

  1845.     int i;

  1846. 

  1847.     if (s->mp3decctx[0])

  1848.         av_freep(&s->mp3decctx[0]->fdsp);

  1849. 

  1850.     for (i = 0; i < s->frames; i++)

  1851.         av_freep(&s->mp3decctx[i]);

  1852. 

  1853.     return 0;

  1854. }

  1855. 

  1856. 

  1857. static av_cold int decode_init_mp3on4(AVCodecContext * avctx)

  1858. {

  1859.     MP3On4DecodeContext *s = avctx->priv_data;

  1860.     MPEG4AudioConfig cfg;

  1861.     int i, ret;

  1862. 

  1863.     if ((avctx->extradata_size < 2) || !avctx->extradata) {

  1864.         av_log(avctx, AV_LOG_ERROR, "Codec extradata missing or too short.\n");

  1865.         return AVERROR_INVALIDDATA;

  1866.     }

  1867. 

  1868.     avpriv_mpeg4audio_get_config2(&cfg, avctx->extradata,

  1869.                                   avctx->extradata_size, 1, avctx);

  1870.     if (!cfg.chan_config || cfg.chan_config > 7) {

  1871.         av_log(avctx, AV_LOG_ERROR, "Invalid channel config number.\n");

  1872.         return AVERROR_INVALIDDATA;

  1873.     }

  1874.     s->frames             = mp3Frames[cfg.chan_config];

  1875.     s->coff               = chan_offset[cfg.chan_config];

  1876.     avctx->channels       = ff_mpeg4audio_channels[cfg.chan_config];

  1877.     avctx->channel_layout = chan_layout[cfg.chan_config];

  1878. 

  1879.     if (cfg.sample_rate < 16000)

  1880.         s->syncword = 0xffe00000;

  1881.     else

  1882.         s->syncword = 0xfff00000;

  1883. 

  1884.     /* Init the first mp3 decoder in standard way, so that all tables get builded

  1885.      * We replace avctx->priv_data with the context of the first decoder so that

  1886.      * decode_init() does not have to be changed.

  1887.      * Other decoders will be initialized here copying data from the first context

  1888.      */

  1889.     // Allocate zeroed memory for the first decoder context

  1890.     s->mp3decctx[0] = av_mallocz(sizeof(MPADecodeContext));

  1891.     if (!s->mp3decctx[0])

  1892.         goto alloc_fail;

  1893.     // Put decoder context in place to make init_decode() happy

  1894.     avctx->priv_data = s->mp3decctx[0];

  1895.     ret = decode_init(avctx);

  1896.     // Restore mp3on4 context pointer

  1897.     avctx->priv_data = s;

  1898.     if (ret < 0) {

  1899.         decode_close_mp3on4(avctx);

  1900.         return ret;

  1901.     }

  1902.     s->mp3decctx[0]->adu_mode = 1; // Set adu mode

  1903. 

  1904.     /* Create a separate codec/context for each frame (first is already ok).

  1905.      * Each frame is 1 or 2 channels - up to 5 frames allowed

  1906.      */

  1907.     for (i = 1; i < s->frames; i++) {

  1908.         s->mp3decctx[i] = av_mallocz(sizeof(MPADecodeContext));

  1909.         if (!s->mp3decctx[i])

  1910.             goto alloc_fail;

  1911.         s->mp3decctx[i]->adu_mode = 1;

  1912.         s->mp3decctx[i]->avctx = avctx;

  1913.         s->mp3decctx[i]->mpadsp = s->mp3decctx[0]->mpadsp;

  1914.         s->mp3decctx[i]->fdsp = s->mp3decctx[0]->fdsp;

  1915.     }

  1916. 

  1917.     return 0;

  1918. alloc_fail:

  1919.     decode_close_mp3on4(avctx);

  1920.     return AVERROR(ENOMEM);

  1921. }

  1922. 

  1923. 

  1924. static void flush_mp3on4(AVCodecContext *avctx)

  1925. {

  1926.     int i;

  1927.     MP3On4DecodeContext *s = avctx->priv_data;

  1928. 

  1929.     for (i = 0; i < s->frames; i++)

  1930.         mp_flush(s->mp3decctx[i]);

  1931. }

  1932. 

  1933. 

  1934. static int decode_frame_mp3on4(AVCodecContext *avctx, void *data,

  1935.                                int *got_frame_ptr, AVPacket *avpkt)

  1936. {

  1937.     AVFrame *frame         = data;

  1938.     const uint8_t *buf     = avpkt->data;

  1939.     int buf_size           = avpkt->size;

  1940.     MP3On4DecodeContext *s = avctx->priv_data;

  1941.     MPADecodeContext *m;

  1942.     int fsize, len = buf_size, out_size = 0;

  1943.     uint32_t header;

  1944.     OUT_INT **out_samples;

  1945.     OUT_INT *outptr[2];

  1946.     int fr, ch, ret;

  1947. 

  1948.     /* get output buffer */

  1949.     frame->nb_samples = MPA_FRAME_SIZE;

  1950.     if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)

  1951.         return ret;

  1952.     out_samples = (OUT_INT **)frame->extended_data;

  1953. 

  1954.     // Discard too short frames

  1955.     if (buf_size < HEADER_SIZE)

  1956.         return AVERROR_INVALIDDATA;

  1957. 

  1958.     avctx->bit_rate = 0;

  1959. 

  1960.     ch = 0;

  1961.     for (fr = 0; fr < s->frames; fr++) {

  1962.         fsize = AV_RB16(buf) >> 4;

  1963.         fsize = FFMIN3(fsize, len, MPA_MAX_CODED_FRAME_SIZE);

  1964.         m     = s->mp3decctx[fr];

  1965.         av_assert1(m);

  1966. 

  1967.         if (fsize < HEADER_SIZE) {

  1968.             av_log(avctx, AV_LOG_ERROR, "Frame size smaller than header size\n");

  1969.             return AVERROR_INVALIDDATA;

  1970.         }

  1971.         header = (AV_RB32(buf) & 0x000fffff) | s->syncword; // patch header

  1972. 

  1973.         ret = avpriv_mpegaudio_decode_header((MPADecodeHeader *)m, header);

  1974.         if (ret < 0) {

  1975.             av_log(avctx, AV_LOG_ERROR, "Bad header, discard block\n");

  1976.             return AVERROR_INVALIDDATA;

  1977.         }

  1978. 

  1979.         if (ch + m->nb_channels > avctx->channels ||

  1980.             s->coff[fr] + m->nb_channels > avctx->channels) {

  1981.             av_log(avctx, AV_LOG_ERROR, "frame channel count exceeds codec "

  1982.                                         "channel count\n");

  1983.             return AVERROR_INVALIDDATA;

  1984.         }

  1985.         ch += m->nb_channels;

  1986. 

  1987.         outptr[0] = out_samples[s->coff[fr]];

  1988.         if (m->nb_channels > 1)

  1989.             outptr[1] = out_samples[s->coff[fr] + 1];

  1990. 

  1991.         if ((ret = mp_decode_frame(m, outptr, buf, fsize)) < 0) {

  1992.             av_log(avctx, AV_LOG_ERROR, "failed to decode channel %d\n", ch);

  1993.             memset(outptr[0], 0, MPA_FRAME_SIZE*sizeof(OUT_INT));

  1994.             if (m->nb_channels > 1)

  1995.                 memset(outptr[1], 0, MPA_FRAME_SIZE*sizeof(OUT_INT));

  1996.             ret = m->nb_channels * MPA_FRAME_SIZE*sizeof(OUT_INT);

  1997.         }

  1998. 

  1999.         out_size += ret;

  2000.         buf      += fsize;

  2001.         len      -= fsize;

  2002. 

  2003.         avctx->bit_rate += m->bit_rate;

  2004.     }

  2005.     if (ch != avctx->channels) {

  2006.         av_log(avctx, AV_LOG_ERROR, "failed to decode all channels\n");

  2007.         return AVERROR_INVALIDDATA;

  2008.     }

  2009. 

  2010.     /* update codec info */

  2011.     avctx->sample_rate = s->mp3decctx[0]->sample_rate;

  2012. 

  2013.     frame->nb_samples = out_size / (avctx->channels * sizeof(OUT_INT));

  2014.     *got_frame_ptr    = 1;

  2015. 

  2016.     return buf_size;

  2017. }

  2018. #endif /* CONFIG_MP3ON4_DECODER || CONFIG_MP3ON4FLOAT_DECODER */