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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 Libav.

  6.  *

  7.  * Libav 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.  * Libav 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 Libav; 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/float_dsp.h"

  31. #include "avcodec.h"

  32. #include "get_bits.h"

  33. #include "internal.h"

  34. #include "mathops.h"

  35. #include "mpegaudiodsp.h"

  36. 

  37. /*

  38.  * TODO:

  39.  *  - test lsf / mpeg25 extensively.

  40.  */

  41. 

  42. #include "mpegaudio.h"

  43. #include "mpegaudiodecheader.h"

  44. 

  45. #define BACKSTEP_SIZE 512

  46. #define EXTRABYTES 24

  47. #define LAST_BUF_SIZE 2 * BACKSTEP_SIZE + EXTRABYTES

  48. 

  49. /* layer 3 "granule" */

  50. typedef struct GranuleDef {

  51.     uint8_t scfsi;

  52.     int part2_3_length;

  53.     int big_values;

  54.     int global_gain;

  55.     int scalefac_compress;

  56.     uint8_t block_type;

  57.     uint8_t switch_point;

  58.     int table_select[3];

  59.     int subblock_gain[3];

  60.     uint8_t scalefac_scale;

  61.     uint8_t count1table_select;

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

  63.     int preflag;

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

  65.     uint8_t scale_factors[40];

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

  67. } GranuleDef;

  68. 

  69. typedef struct MPADecodeContext {

  70.     MPA_DECODE_HEADER

  71.     uint8_t last_buf[LAST_BUF_SIZE];

  72.     int last_buf_size;

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

  74.     uint32_t free_format_next_header;

  75.     GetBitContext gb;

  76.     GetBitContext in_gb;

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

  78.     int synth_buf_offset[MPA_MAX_CHANNELS];

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

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

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

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

  83.     int dither_state;

  84.     int err_recognition;

  85.     AVCodecContext* avctx;

  86.     MPADSPContext mpadsp;

  87.     AVFloatDSPContext fdsp;

  88.     AVFrame *frame;

  89. } MPADecodeContext;

  90. 

  91. #define HEADER_SIZE 4

  92. 

  93. #include "mpegaudiodata.h"

  94. #include "mpegaudiodectab.h"

  95. 

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

  97. static VLC huff_vlc[16];

  98. static VLC_TYPE huff_vlc_tables[

  99.     0 + 128 + 128 + 128 + 130 + 128 + 154 + 166 +

  100.   142 + 204 + 190 + 170 + 542 + 460 + 662 + 414

  101.   ][2];

  102. static const int huff_vlc_tables_sizes[16] = {

  103.     0,  128,  128,  128,  130,  128,  154,  166,

  104.   142,  204,  190,  170,  542,  460,  662,  414

  105. };

  106. static VLC huff_quad_vlc[2];

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

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

  109. /* computed from band_size_long */

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

  111. #include "mpegaudio_tablegen.h"

  112. /* intensity stereo coef table */

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

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

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

  116. 

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

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

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

  120. 

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

  122.     division_tab3, division_tab5, NULL, division_tab9

  123. };

  124. 

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

  126. static uint16_t scale_factor_modshift[64];

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

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

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

  130. 

  131. #define SCALE_GEN(v) \

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

  133. 

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

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

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

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

  138. };

  139. 

  140. /**

  141.  * Convert region offsets to region sizes and truncate

  142.  * size to big_values.

  143.  */

  144. static void region_offset2size(GranuleDef *g)

  145. {

  146.     int i, k, j = 0;

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

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

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

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

  151.         j = k;

  152.     }

  153. }

  154. 

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

  156. {

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

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

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

  160.         else

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

  162.     } else {

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

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

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

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

  167.         else

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

  169.     }

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

  171. }

  172. 

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

  174.                              int ra1, int ra2)

  175. {

  176.     int l;

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

  178.     /* should not overflow */

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

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

  181. }

  182. 

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

  184. {

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

  186.         if (g->switch_point) {

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

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

  189.                 exponents as long blocks */

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

  191.                 g->long_end = 8;

  192.             else

  193.                 g->long_end = 6;

  194. 

  195.             g->short_start = 3;

  196.         } else {

  197.             g->long_end    = 0;

  198.             g->short_start = 0;

  199.         }

  200.     } else {

  201.         g->short_start = 13;

  202.         g->long_end    = 22;

  203.     }

  204. }

  205. 

  206. /* layer 1 unscaling */

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

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

  209. {

  210.     int shift, mod;

  211.     int64_t val;

  212. 

  213.     shift   = scale_factor_modshift[scale_factor];

  214.     mod     = shift & 3;

  215.     shift >>= 2;

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

  217.     shift  += n;

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

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

  220. }

  221. 

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

  223. {

  224.     int shift, mod, val;

  225. 

  226.     shift   = scale_factor_modshift[scale_factor];

  227.     mod     = shift & 3;

  228.     shift >>= 2;

  229. 

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

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

  232.     if (shift > 0)

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

  234.     return val;

  235. }

  236. 

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

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

  239. {

  240.     unsigned int m;

  241.     int e;

  242. 

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

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

  245.     e -= exponent >> 2;

  246.     assert(e >= 1);

  247.     if (e > 31)

  248.         return 0;

  249.     m = (m + (1 << (e - 1))) >> e;

  250. 

  251.     return m;

  252. }

  253. 

  254. static av_cold void decode_init_static(void)

  255. {

  256.     int i, j, k;

  257.     int offset;

  258. 

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

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

  261.         int shift, mod;

  262.         /* 1.0 (i = 3) is normalized to 2 ^ FRAC_BITS */

  263.         shift = i / 3;

  264.         mod   = i % 3;

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

  266.     }

  267. 

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

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

  270.         int n, norm;

  271.         n = i + 2;

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

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

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

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

  276.         av_dlog(NULL, "%d: norm=%x s=%x %x %x\n", i, norm,

  277.                 scale_factor_mult[i][0],

  278.                 scale_factor_mult[i][1],

  279.                 scale_factor_mult[i][2]);

  280.     }

  281. 

  282.     RENAME(ff_mpa_synth_init)(RENAME(ff_mpa_synth_window));

  283. 

  284.     /* huffman decode tables */

  285.     offset = 0;

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

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

  288.         int xsize, x, y;

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

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

  291. 

  292.         xsize = h->xsize;

  293. 

  294.         j = 0;

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

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

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

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

  299.             }

  300.         }

  301. 

  302.         /* XXX: fail test */

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

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

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

  306.                  tmp_bits, 1, 1, tmp_codes, 2, 2,

  307.                  INIT_VLC_USE_NEW_STATIC);

  308.         offset += huff_vlc_tables_sizes[i];

  309.     }

  310.     assert(offset == FF_ARRAY_ELEMS(huff_vlc_tables));

  311. 

  312.     offset = 0;

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

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

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

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

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

  318.                  INIT_VLC_USE_NEW_STATIC);

  319.         offset += huff_quad_vlc_tables_sizes[i];

  320.     }

  321.     assert(offset == FF_ARRAY_ELEMS(huff_quad_vlc_tables));

  322. 

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

  324.         k = 0;

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

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

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

  328.         }

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

  330.     }

  331. 

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

  333. 

  334.     mpegaudio_tableinit();

  335. 

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

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

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

  339.                 int val1, val2, val3, steps;

  340.                 int val = j;

  341.                 steps   = ff_mpa_quant_steps[i];

  342.                 val1    = val % steps;

  343.                 val    /= steps;

  344.                 val2    = val % steps;

  345.                 val3    = val / steps;

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

  347.             }

  348.         }

  349.     }

  350. 

  351. 

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

  353.         float f;

  354.         INTFLOAT v;

  355.         if (i != 6) {

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

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

  358.         } else {

  359.             v = FIXR(1.0);

  360.         }

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

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

  363.     }

  364.     /* invalid values */

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

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

  367. 

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

  369.         double f;

  370.         int e, k;

  371. 

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

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

  374.             f = pow(2.0, e / 4.0);

  375.             k = i & 1;

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

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

  378.             av_dlog(NULL, "is_table_lsf %d %d: %f %f\n",

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

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

  381.         }

  382.     }

  383. 

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

  385.         float ci, cs, ca;

  386.         ci = ci_table[i];

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

  388.         ca = cs * ci;

  389. #if !CONFIG_FLOAT

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

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

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

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

  394. #else

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

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

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

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

  399. #endif

  400.     }

  401. }

  402. 

  403. static av_cold int decode_init(AVCodecContext * avctx)

  404. {

  405.     static int initialized_tables = 0;

  406.     MPADecodeContext *s = avctx->priv_data;

  407. 

  408.     if (!initialized_tables) {

  409.         decode_init_static();

  410.         initialized_tables = 1;

  411.     }

  412. 

  413.     s->avctx = avctx;

  414. 

  415.     avpriv_float_dsp_init(&s->fdsp, avctx->flags & CODEC_FLAG_BITEXACT);

  416.     ff_mpadsp_init(&s->mpadsp);

  417. 

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

  419.         avctx->codec_id != AV_CODEC_ID_MP3ON4)

  420.         avctx->sample_fmt = OUT_FMT;

  421.     else

  422.         avctx->sample_fmt = OUT_FMT_P;

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

  424. 

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

  426.         s->adu_mode = 1;

  427. 

  428.     return 0;

  429. }

  430. 

  431. #define C3 FIXHR(0.86602540378443864676/2)

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

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

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

  435. 

  436. /* 12 points IMDCT. We compute it "by hand" by factorizing obvious

  437.    cases. */

  438. static void imdct12(INTFLOAT *out, INTFLOAT *in)

  439. {

  440.     INTFLOAT in0, in1, in2, in3, in4, in5, t1, t2;

  441. 

  442.     in0  = in[0*3];

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

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

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

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

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

  448.     in5 += in3;

  449.     in3 += in1;

  450. 

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

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

  453. 

  454.     t1   = in0 - in4;

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

  456. 

  457.     out[ 7] =

  458.     out[10] = t1 + t2;

  459.     out[ 1] =

  460.     out[ 4] = t1 - t2;

  461. 

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

  463.     in4     = in0 + in2;

  464.     in5    += 2*in1;

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

  466.     out[ 8] =

  467.     out[ 9] = in4 + in1;

  468.     out[ 2] =

  469.     out[ 3] = in4 - in1;

  470. 

  471.     in0    -= in2;

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

  473.     out[ 0] =

  474.     out[ 5] = in0 - in5;

  475.     out[ 6] =

  476.     out[11] = in0 + in5;

  477. }

  478. 

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

  480. static int mp_decode_layer1(MPADecodeContext *s)

  481. {

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

  483.     uint8_t allocation[MPA_MAX_CHANNELS][SBLIMIT];

  484.     uint8_t scale_factors[MPA_MAX_CHANNELS][SBLIMIT];

  485. 

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

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

  488.     else

  489.         bound = SBLIMIT;

  490. 

  491.     /* allocation bits */

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

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

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

  495.         }

  496.     }

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

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

  499. 

  500.     /* scale factors */

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

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

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

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

  505.         }

  506.     }

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

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

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

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

  511.         }

  512.     }

  513. 

  514.     /* compute samples */

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

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

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

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

  519.                 if (n) {

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

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

  522.                 } else {

  523.                     v = 0;

  524.                 }

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

  526.             }

  527.         }

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

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

  530.             if (n) {

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

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

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

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

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

  536.             } else {

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

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

  539.             }

  540.         }

  541.     }

  542.     return 12;

  543. }

  544. 

  545. static int mp_decode_layer2(MPADecodeContext *s)

  546. {

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

  548.     const unsigned char *alloc_table;

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

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

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

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

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

  554. 

  555.     /* select decoding table */

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

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

  558.     sblimit     = ff_mpa_sblimit_table[table];

  559.     alloc_table = ff_mpa_alloc_tables[table];

  560. 

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

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

  563.     else

  564.         bound = sblimit;

  565. 

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

  567. 

  568.     /* sanity check */

  569.     if (bound > sblimit)

  570.         bound = sblimit;

  571. 

  572.     /* parse bit allocation */

  573.     j = 0;

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

  575.         bit_alloc_bits = alloc_table[j];

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

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

  578.         j += 1 << bit_alloc_bits;

  579.     }

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

  581.         bit_alloc_bits = alloc_table[j];

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

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

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

  585.         j += 1 << bit_alloc_bits;

  586.     }

  587. 

  588.     /* scale codes */

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

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

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

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

  593.         }

  594.     }

  595. 

  596.     /* scale factors */

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

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

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

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

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

  602.                 default:

  603.                 case 0:

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

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

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

  607.                     break;

  608.                 case 2:

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

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

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

  612.                     break;

  613.                 case 1:

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

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

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

  617.                     break;

  618.                 case 3:

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

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

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

  622.                     break;

  623.                 }

  624.             }

  625.         }

  626.     }

  627. 

  628.     /* samples */

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

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

  631.             j = 0;

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

  633.                 bit_alloc_bits = alloc_table[j];

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

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

  636.                     if (b) {

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

  638.                         qindex = alloc_table[j+b];

  639.                         bits = ff_mpa_quant_bits[qindex];

  640.                         if (bits < 0) {

  641.                             int v2;

  642.                             /* 3 values at the same time */

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

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

  645.                             steps  = ff_mpa_quant_steps[qindex];

  646. 

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

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

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

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

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

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

  653.                         } else {

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

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

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

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

  658.                             }

  659.                         }

  660.                     } else {

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

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

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

  664.                     }

  665.                 }

  666.                 /* next subband in alloc table */

  667.                 j += 1 << bit_alloc_bits;

  668.             }

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

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

  671.                 bit_alloc_bits = alloc_table[j];

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

  673.                 if (b) {

  674.                     int mant, scale0, scale1;

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

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

  677.                     qindex = alloc_table[j+b];

  678.                     bits = ff_mpa_quant_bits[qindex];

  679.                     if (bits < 0) {

  680.                         /* 3 values at the same time */

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

  682.                         steps = ff_mpa_quant_steps[qindex];

  683.                         mant = v % steps;

  684.                         v = v / steps;

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

  686.                             l2_unscale_group(steps, mant, scale0);

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

  688.                             l2_unscale_group(steps, mant, scale1);

  689.                         mant = v % steps;

  690.                         v = v / steps;

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

  692.                             l2_unscale_group(steps, mant, scale0);

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

  694.                             l2_unscale_group(steps, mant, scale1);

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

  696.                             l2_unscale_group(steps, v, scale0);

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

  698.                             l2_unscale_group(steps, v, scale1);

  699.                     } else {

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

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

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

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

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

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

  706.                         }

  707.                     }

  708.                 } else {

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

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

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

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

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

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

  715.                 }

  716.                 /* next subband in alloc table */

  717.                 j += 1 << bit_alloc_bits;

  718.             }

  719.             /* fill remaining samples to zero */

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

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

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

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

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

  725.                 }

  726.             }

  727.         }

  728.     }

  729.     return 3 * 12;

  730. }

  731. 

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

  733.     if (n == 3) {                   \

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

  735.         dst   = sf - 3 * m;         \

  736.         sf    = m;                  \

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

  738.         dst  = sf & 3;              \

  739.         sf >>= 2;                   \

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

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

  742.         dst   = sf - 5 * m;         \

  743.         sf    = m;                  \

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

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

  746.         dst   = sf - 6 * m;         \

  747.         sf    = m;                  \

  748.     } else {                        \

  749.         dst = 0;                    \

  750.     }

  751. 

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

  753.                                            int n3)

  754. {

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

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

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

  758.     slen[0] = sf;

  759. }

  760. 

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

  762.                                          int16_t *exponents)

  763. {

  764.     const uint8_t *bstab, *pretab;

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

  766.     int16_t *exp_ptr;

  767. 

  768.     exp_ptr = exponents;

  769.     gain    = g->global_gain - 210;

  770.     shift   = g->scalefac_scale + 1;

  771. 

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

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

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

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

  776.         len = bstab[i];

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

  778.             *exp_ptr++ = v0;

  779.     }

  780. 

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

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

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

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

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

  786.         k        = g->long_end;

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

  788.             len = bstab[i];

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

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

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

  792.                     *exp_ptr++ = v0;

  793.             }

  794.         }

  795.     }

  796. }

  797. 

  798. /* handle n = 0 too */

  799. static inline int get_bitsz(GetBitContext *s, int n)

  800. {

  801.     return n ? get_bits(s, n) : 0;

  802. }

  803. 

  804. 

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

  806.                           int *end_pos2)

  807. {

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

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

  810.         s->in_gb.buffer = NULL;

  811.         assert((get_bits_count(&s->gb) & 7) == 0);

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

  813.         *end_pos2 =

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

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

  816.     }

  817. }

  818. 

  819. /* Following is a optimized code for

  820.             INTFLOAT v = *src

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

  822.                 v = -v;

  823.             *dst = v;

  824. */

  825. #if CONFIG_FLOAT

  826. #define READ_FLIP_SIGN(dst,src)                     \

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

  828.     AV_WN32A(dst, v);

  829. #else

  830. #define READ_FLIP_SIGN(dst,src)     \

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

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

  833. #endif

  834. 

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

  836.                           int16_t *exponents, int end_pos2)

  837. {

  838.     int s_index;

  839.     int i;

  840.     int last_pos, bits_left;

  841.     VLC *vlc;

  842.     int end_pos = FFMIN(end_pos2, s->gb.size_in_bits);

  843. 

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

  845.     s_index = 0;

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

  847.         int j, k, l, linbits;

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

  849.         if (j == 0)

  850.             continue;

  851.         /* select vlc table */

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

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

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

  855.         vlc     = &huff_vlc[l];

  856. 

  857.         if (!l) {

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

  859.             s_index += 2 * j;

  860.             continue;

  861.         }

  862. 

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

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

  865.             int exponent, x, y;

  866.             int v;

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

  868. 

  869.             if (pos >= end_pos){

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

  871.                 if (pos >= end_pos)

  872.                     break;

  873.             }

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

  875. 

  876.             if (!y) {

  877.                 g->sb_hybrid[s_index  ] =

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

  879.                 s_index += 2;

  880.                 continue;

  881.             }

  882. 

  883.             exponent= exponents[s_index];

  884. 

  885.             av_dlog(s->avctx, "region=%d n=%d x=%d y=%d exp=%d\n",

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

  887.             if (y & 16) {

  888.                 x = y >> 5;

  889.                 y = y & 0x0f;

  890.                 if (x < 15) {

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

  892.                 } else {

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

  894.                     v  = l3_unscale(x, exponent);

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

  896.                         v = -v;

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

  898.                 }

  899.                 if (y < 15) {

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

  901.                 } else {

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

  903.                     v  = l3_unscale(y, exponent);

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

  905.                         v = -v;

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

  907.                 }

  908.             } else {

  909.                 x = y >> 5;

  910.                 y = y & 0x0f;

  911.                 x += y;

  912.                 if (x < 15) {

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

  914.                 } else {

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

  916.                     v  = l3_unscale(x, exponent);

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

  918.                         v = -v;

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

  920.                 }

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

  922.             }

  923.             s_index += 2;

  924.         }

  925.     }

  926. 

  927.     /* high frequencies */

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

  929.     last_pos = 0;

  930.     while (s_index <= 572) {

  931.         int pos, code;

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

  933.         if (pos >= end_pos) {

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

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

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

  937.                 s_index -= 4;

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

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

  940.                 if(s->err_recognition & AV_EF_BITSTREAM)

  941.                     s_index=0;

  942.                 break;

  943.             }

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

  945.             if (pos >= end_pos)

  946.                 break;

  947.         }

  948.         last_pos = pos;

  949. 

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

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

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

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

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

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

  956.         while (code) {

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

  958.             int v;

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

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

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

  962.         }

  963.         s_index += 4;

  964.     }

  965.     /* skip extension bits */

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

  967.     if (bits_left < 0 && (s->err_recognition & AV_EF_BUFFER)) {

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

  969.         s_index=0;

  970.     } else if (bits_left > 0 && (s->err_recognition & AV_EF_BUFFER)) {

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

  972.         s_index = 0;

  973.     }

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

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

  976. 

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

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

  979. 

  980.     return 0;

  981. }

  982. 

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

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

  985.    complicated */

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

  987. {

  988.     int i, j, len;

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

  990.     INTFLOAT tmp[576];

  991. 

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

  993.         return;

  994. 

  995.     if (g->switch_point) {

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

  997.             ptr = g->sb_hybrid + 36;

  998.         else

  999.             ptr = g->sb_hybrid + 72;

  1000.     } else {

  1001.         ptr = g->sb_hybrid;

  1002.     }

  1003. 

  1004.     for (i = g->short_start; i < 13; i++) {

  1005.         len  = band_size_short[s->sample_rate_index][i];

  1006.         ptr1 = ptr;

  1007.         dst  = tmp;

  1008.         for (j = len; j > 0; j--) {

  1009.             *dst++ = ptr[0*len];

  1010.             *dst++ = ptr[1*len];

  1011.             *dst++ = ptr[2*len];

  1012.             ptr++;

  1013.         }

  1014.         ptr += 2 * len;

  1015.         memcpy(ptr1, tmp, len * 3 * sizeof(*ptr1));

  1016.     }

  1017. }

  1018. 

  1019. #define ISQRT2 FIXR(0.70710678118654752440)

  1020. 

  1021. static void compute_stereo(MPADecodeContext *s, GranuleDef *g0, GranuleDef *g1)

  1022. {

  1023.     int i, j, k, l;

  1024.     int sf_max, sf, len, non_zero_found;

  1025.     INTFLOAT (*is_tab)[16], *tab0, *tab1, tmp0, tmp1, v1, v2;

  1026.     int non_zero_found_short[3];

  1027. 

  1028.     /* intensity stereo */

  1029.     if (s->mode_ext & MODE_EXT_I_STEREO) {

  1030.         if (!s->lsf) {

  1031.             is_tab = is_table;

  1032.             sf_max = 7;

  1033.         } else {

  1034.             is_tab = is_table_lsf[g1->scalefac_compress & 1];

  1035.             sf_max = 16;

  1036.         }

  1037. 

  1038.         tab0 = g0->sb_hybrid + 576;

  1039.         tab1 = g1->sb_hybrid + 576;

  1040. 

  1041.         non_zero_found_short[0] = 0;

  1042.         non_zero_found_short[1] = 0;

  1043.         non_zero_found_short[2] = 0;

  1044.         k = (13 - g1->short_start) * 3 + g1->long_end - 3;

  1045.         for (i = 12; i >= g1->short_start; i--) {

  1046.             /* for last band, use previous scale factor */

  1047.             if (i != 11)

  1048.                 k -= 3;

  1049.             len = band_size_short[s->sample_rate_index][i];

  1050.             for (l = 2; l >= 0; l--) {

  1051.                 tab0 -= len;

  1052.                 tab1 -= len;

  1053.                 if (!non_zero_found_short[l]) {

  1054.                     /* test if non zero band. if so, stop doing i-stereo */

  1055.                     for (j = 0; j < len; j++) {

  1056.                         if (tab1[j] != 0) {

  1057.                             non_zero_found_short[l] = 1;

  1058.                             goto found1;

  1059.                         }

  1060.                     }

  1061.                     sf = g1->scale_factors[k + l];

  1062.                     if (sf >= sf_max)

  1063.                         goto found1;

  1064. 

  1065.                     v1 = is_tab[0][sf];

  1066.                     v2 = is_tab[1][sf];

  1067.                     for (j = 0; j < len; j++) {

  1068.                         tmp0    = tab0[j];

  1069.                         tab0[j] = MULLx(tmp0, v1, FRAC_BITS);

  1070.                         tab1[j] = MULLx(tmp0, v2, FRAC_BITS);

  1071.                     }

  1072.                 } else {

  1073. found1:

  1074.                     if (s->mode_ext & MODE_EXT_MS_STEREO) {

  1075.                         /* lower part of the spectrum : do ms stereo

  1076.                            if enabled */

  1077.                         for (j = 0; j < len; j++) {

  1078.                             tmp0    = tab0[j];

  1079.                             tmp1    = tab1[j];

  1080.                             tab0[j] = MULLx(tmp0 + tmp1, ISQRT2, FRAC_BITS);

  1081.                             tab1[j] = MULLx(tmp0 - tmp1, ISQRT2, FRAC_BITS);

  1082.                         }

  1083.                     }

  1084.                 }

  1085.             }

  1086.         }

  1087. 

  1088.         non_zero_found = non_zero_found_short[0] |

  1089.                          non_zero_found_short[1] |

  1090.                          non_zero_found_short[2];

  1091. 

  1092.         for (i = g1->long_end - 1;i >= 0;i--) {

  1093.             len   = band_size_long[s->sample_rate_index][i];

  1094.             tab0 -= len;

  1095.             tab1 -= len;

  1096.             /* test if non zero band. if so, stop doing i-stereo */

  1097.             if (!non_zero_found) {

  1098.                 for (j = 0; j < len; j++) {

  1099.                     if (tab1[j] != 0) {

  1100.                         non_zero_found = 1;

  1101.                         goto found2;

  1102.                     }

  1103.                 }

  1104.                 /* for last band, use previous scale factor */

  1105.                 k  = (i == 21) ? 20 : i;

  1106.                 sf = g1->scale_factors[k];

  1107.                 if (sf >= sf_max)

  1108.                     goto found2;

  1109.                 v1 = is_tab[0][sf];

  1110.                 v2 = is_tab[1][sf];

  1111.                 for (j = 0; j < len; j++) {

  1112.                     tmp0    = tab0[j];

  1113.                     tab0[j] = MULLx(tmp0, v1, FRAC_BITS);

  1114.                     tab1[j] = MULLx(tmp0, v2, FRAC_BITS);

  1115.                 }

  1116.             } else {

  1117. found2:

  1118.                 if (s->mode_ext & MODE_EXT_MS_STEREO) {

  1119.                     /* lower part of the spectrum : do ms stereo

  1120.                        if enabled */

  1121.                     for (j = 0; j < len; j++) {

  1122.                         tmp0    = tab0[j];

  1123.                         tmp1    = tab1[j];

  1124.                         tab0[j] = MULLx(tmp0 + tmp1, ISQRT2, FRAC_BITS);

  1125.                         tab1[j] = MULLx(tmp0 - tmp1, ISQRT2, FRAC_BITS);

  1126.                     }

  1127.                 }

  1128.             }

  1129.         }

  1130.     } else if (s->mode_ext & MODE_EXT_MS_STEREO) {

  1131.         /* ms stereo ONLY */

  1132.         /* NOTE: the 1/sqrt(2) normalization factor is included in the

  1133.            global gain */

  1134. #if CONFIG_FLOAT

  1135.        s->fdsp.butterflies_float(g0->sb_hybrid, g1->sb_hybrid, 576);

  1136. #else

  1137.         tab0 = g0->sb_hybrid;

  1138.         tab1 = g1->sb_hybrid;

  1139.         for (i = 0; i < 576; i++) {

  1140.             tmp0    = tab0[i];

  1141.             tmp1    = tab1[i];

  1142.             tab0[i] = tmp0 + tmp1;

  1143.             tab1[i] = tmp0 - tmp1;

  1144.         }

  1145. #endif

  1146.     }

  1147. }

  1148. 

  1149. #if CONFIG_FLOAT

  1150. #define AA(j) do {                                                      \

  1151.         float tmp0 = ptr[-1-j];                                         \

  1152.         float tmp1 = ptr[   j];                                         \

  1153.         ptr[-1-j] = tmp0 * csa_table[j][0] - tmp1 * csa_table[j][1];    \

  1154.         ptr[   j] = tmp0 * csa_table[j][1] + tmp1 * csa_table[j][0];    \

  1155.     } while (0)

  1156. #else

  1157. #define AA(j) do {                                              \

  1158.         int tmp0 = ptr[-1-j];                                   \

  1159.         int tmp1 = ptr[   j];                                   \

  1160.         int tmp2 = MULH(tmp0 + tmp1, csa_table[j][0]);          \

  1161.         ptr[-1-j] = 4 * (tmp2 - MULH(tmp1, csa_table[j][2]));   \

  1162.         ptr[   j] = 4 * (tmp2 + MULH(tmp0, csa_table[j][3]));   \

  1163.     } while (0)

  1164. #endif

  1165. 

  1166. static void compute_antialias(MPADecodeContext *s, GranuleDef *g)

  1167. {

  1168.     INTFLOAT *ptr;

  1169.     int n, i;

  1170. 

  1171.     /* we antialias only "long" bands */

  1172.     if (g->block_type == 2) {

  1173.         if (!g->switch_point)

  1174.             return;

  1175.         /* XXX: check this for 8000Hz case */

  1176.         n = 1;

  1177.     } else {

  1178.         n = SBLIMIT - 1;

  1179.     }

  1180. 

  1181.     ptr = g->sb_hybrid + 18;

  1182.     for (i = n; i > 0; i--) {

  1183.         AA(0);

  1184.         AA(1);

  1185.         AA(2);

  1186.         AA(3);

  1187.         AA(4);

  1188.         AA(5);

  1189.         AA(6);

  1190.         AA(7);

  1191. 

  1192.         ptr += 18;

  1193.     }

  1194. }

  1195. 

  1196. static void compute_imdct(MPADecodeContext *s, GranuleDef *g,

  1197.                           INTFLOAT *sb_samples, INTFLOAT *mdct_buf)

  1198. {

  1199.     INTFLOAT *win, *out_ptr, *ptr, *buf, *ptr1;

  1200.     INTFLOAT out2[12];

  1201.     int i, j, mdct_long_end, sblimit;

  1202. 

  1203.     /* find last non zero block */

  1204.     ptr  = g->sb_hybrid + 576;

  1205.     ptr1 = g->sb_hybrid + 2 * 18;

  1206.     while (ptr >= ptr1) {

  1207.         int32_t *p;

  1208.         ptr -= 6;

  1209.         p    = (int32_t*)ptr;

  1210.         if (p[0] | p[1] | p[2] | p[3] | p[4] | p[5])

  1211.             break;

  1212.     }

  1213.     sblimit = ((ptr - g->sb_hybrid) / 18) + 1;

  1214. 

  1215.     if (g->block_type == 2) {

  1216.         /* XXX: check for 8000 Hz */

  1217.         if (g->switch_point)

  1218.             mdct_long_end = 2;

  1219.         else

  1220.             mdct_long_end = 0;

  1221.     } else {

  1222.         mdct_long_end = sblimit;

  1223.     }

  1224. 

  1225.     s->mpadsp.RENAME(imdct36_blocks)(sb_samples, mdct_buf, g->sb_hybrid,

  1226.                                      mdct_long_end, g->switch_point,

  1227.                                      g->block_type);

  1228. 

  1229.     buf = mdct_buf + 4*18*(mdct_long_end >> 2) + (mdct_long_end & 3);

  1230.     ptr = g->sb_hybrid + 18 * mdct_long_end;

  1231. 

  1232.     for (j = mdct_long_end; j < sblimit; j++) {

  1233.         /* select frequency inversion */

  1234.         win     = RENAME(ff_mdct_win)[2 + (4  & -(j & 1))];

  1235.         out_ptr = sb_samples + j;

  1236. 

  1237.         for (i = 0; i < 6; i++) {

  1238.             *out_ptr = buf[4*i];

  1239.             out_ptr += SBLIMIT;

  1240.         }

  1241.         imdct12(out2, ptr + 0);

  1242.         for (i = 0; i < 6; i++) {

  1243.             *out_ptr     = MULH3(out2[i    ], win[i    ], 1) + buf[4*(i + 6*1)];

  1244.             buf[4*(i + 6*2)] = MULH3(out2[i + 6], win[i + 6], 1);

  1245.             out_ptr += SBLIMIT;

  1246.         }

  1247.         imdct12(out2, ptr + 1);

  1248.         for (i = 0; i < 6; i++) {

  1249.             *out_ptr     = MULH3(out2[i    ], win[i    ], 1) + buf[4*(i + 6*2)];

  1250.             buf[4*(i + 6*0)] = MULH3(out2[i + 6], win[i + 6], 1);

  1251.             out_ptr += SBLIMIT;

  1252.         }

  1253.         imdct12(out2, ptr + 2);

  1254.         for (i = 0; i < 6; i++) {

  1255.             buf[4*(i + 6*0)] = MULH3(out2[i    ], win[i    ], 1) + buf[4*(i + 6*0)];

  1256.             buf[4*(i + 6*1)] = MULH3(out2[i + 6], win[i + 6], 1);

  1257.             buf[4*(i + 6*2)] = 0;

  1258.         }

  1259.         ptr += 18;

  1260.         buf += (j&3) != 3 ? 1 : (4*18-3);

  1261.     }

  1262.     /* zero bands */

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

  1264.         /* overlap */

  1265.         out_ptr = sb_samples + j;

  1266.         for (i = 0; i < 18; i++) {

  1267.             *out_ptr = buf[4*i];

  1268.             buf[4*i]   = 0;

  1269.             out_ptr += SBLIMIT;

  1270.         }

  1271.         buf += (j&3) != 3 ? 1 : (4*18-3);

  1272.     }

  1273. }

  1274. 

  1275. /* main layer3 decoding function */

  1276. static int mp_decode_layer3(MPADecodeContext *s)

  1277. {

  1278.     int nb_granules, main_data_begin;

  1279.     int gr, ch, blocksplit_flag, i, j, k, n, bits_pos;

  1280.     GranuleDef *g;

  1281.     int16_t exponents[576]; //FIXME try INTFLOAT

  1282. 

  1283.     /* read side info */

  1284.     if (s->lsf) {

  1285.         main_data_begin = get_bits(&s->gb, 8);

  1286.         skip_bits(&s->gb, s->nb_channels);

  1287.         nb_granules = 1;

  1288.     } else {

  1289.         main_data_begin = get_bits(&s->gb, 9);

  1290.         if (s->nb_channels == 2)

  1291.             skip_bits(&s->gb, 3);

  1292.         else

  1293.             skip_bits(&s->gb, 5);

  1294.         nb_granules = 2;

  1295.         for (ch = 0; ch < s->nb_channels; ch++) {

  1296.             s->granules[ch][0].scfsi = 0;/* all scale factors are transmitted */

  1297.             s->granules[ch][1].scfsi = get_bits(&s->gb, 4);

  1298.         }

  1299.     }

  1300. 

  1301.     for (gr = 0; gr < nb_granules; gr++) {

  1302.         for (ch = 0; ch < s->nb_channels; ch++) {

  1303.             av_dlog(s->avctx, "gr=%d ch=%d: side_info\n", gr, ch);

  1304.             g = &s->granules[ch][gr];

  1305.             g->part2_3_length = get_bits(&s->gb, 12);

  1306.             g->big_values     = get_bits(&s->gb,  9);

  1307.             if (g->big_values > 288) {

  1308.                 av_log(s->avctx, AV_LOG_ERROR, "big_values too big\n");

  1309.                 return AVERROR_INVALIDDATA;

  1310.             }

  1311. 

  1312.             g->global_gain = get_bits(&s->gb, 8);

  1313.             /* if MS stereo only is selected, we precompute the

  1314.                1/sqrt(2) renormalization factor */

  1315.             if ((s->mode_ext & (MODE_EXT_MS_STEREO | MODE_EXT_I_STEREO)) ==

  1316.                 MODE_EXT_MS_STEREO)

  1317.                 g->global_gain -= 2;

  1318.             if (s->lsf)

  1319.                 g->scalefac_compress = get_bits(&s->gb, 9);

  1320.             else

  1321.                 g->scalefac_compress = get_bits(&s->gb, 4);

  1322.             blocksplit_flag = get_bits1(&s->gb);

  1323.             if (blocksplit_flag) {

  1324.                 g->block_type = get_bits(&s->gb, 2);

  1325.                 if (g->block_type == 0) {

  1326.                     av_log(s->avctx, AV_LOG_ERROR, "invalid block type\n");

  1327.                     return AVERROR_INVALIDDATA;

  1328.                 }

  1329.                 g->switch_point = get_bits1(&s->gb);

  1330.                 for (i = 0; i < 2; i++)

  1331.                     g->table_select[i] = get_bits(&s->gb, 5);

  1332.                 for (i = 0; i < 3; i++)

  1333.                     g->subblock_gain[i] = get_bits(&s->gb, 3);

  1334.                 init_short_region(s, g);

  1335.             } else {

  1336.                 int region_address1, region_address2;

  1337.                 g->block_type = 0;

  1338.                 g->switch_point = 0;

  1339.                 for (i = 0; i < 3; i++)

  1340.                     g->table_select[i] = get_bits(&s->gb, 5);

  1341.                 /* compute huffman coded region sizes */

  1342.                 region_address1 = get_bits(&s->gb, 4);

  1343.                 region_address2 = get_bits(&s->gb, 3);

  1344.                 av_dlog(s->avctx, "region1=%d region2=%d\n",

  1345.                         region_address1, region_address2);

  1346.                 init_long_region(s, g, region_address1, region_address2);

  1347.             }

  1348.             region_offset2size(g);

  1349.             compute_band_indexes(s, g);

  1350. 

  1351.             g->preflag = 0;

  1352.             if (!s->lsf)

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

  1354.             g->scalefac_scale     = get_bits1(&s->gb);

  1355.             g->count1table_select = get_bits1(&s->gb);

  1356.             av_dlog(s->avctx, "block_type=%d switch_point=%d\n",

  1357.                     g->block_type, g->switch_point);

  1358.         }

  1359.     }

  1360. 

  1361.     if (!s->adu_mode) {

  1362.         int skip;

  1363.         const uint8_t *ptr = s->gb.buffer + (get_bits_count(&s->gb)>>3);

  1364.         int extrasize = av_clip(get_bits_left(&s->gb) >> 3, 0,

  1365.                                 FFMAX(0, LAST_BUF_SIZE - s->last_buf_size));

  1366.         assert((get_bits_count(&s->gb) & 7) == 0);

  1367.         /* now we get bits from the main_data_begin offset */

  1368.         av_dlog(s->avctx, "seekback:%d, lastbuf:%d\n",

  1369.                 main_data_begin, s->last_buf_size);

  1370. 

  1371.         memcpy(s->last_buf + s->last_buf_size, ptr, extrasize);

  1372.         s->in_gb = s->gb;

  1373.         init_get_bits(&s->gb, s->last_buf, s->last_buf_size*8);

  1374. #if !UNCHECKED_BITSTREAM_READER

  1375.         s->gb.size_in_bits_plus8 += extrasize * 8;

  1376. #endif

  1377.         s->last_buf_size <<= 3;

  1378.         for (gr = 0; gr < nb_granules && (s->last_buf_size >> 3) < main_data_begin; gr++) {

  1379.             for (ch = 0; ch < s->nb_channels; ch++) {

  1380.                 g = &s->granules[ch][gr];

  1381.                 s->last_buf_size += g->part2_3_length;

  1382.                 memset(g->sb_hybrid, 0, sizeof(g->sb_hybrid));

  1383.                 compute_imdct(s, g, &s->sb_samples[ch][18 * gr][0], s->mdct_buf[ch]);

  1384.             }

  1385.         }

  1386.         skip = s->last_buf_size - 8 * main_data_begin;

  1387.         if (skip >= s->gb.size_in_bits && s->in_gb.buffer) {

  1388.             skip_bits_long(&s->in_gb, skip - s->gb.size_in_bits);

  1389.             s->gb           = s->in_gb;

  1390.             s->in_gb.buffer = NULL;

  1391.         } else {

  1392.             skip_bits_long(&s->gb, skip);

  1393.         }

  1394.     } else {

  1395.         gr = 0;

  1396.     }

  1397. 

  1398.     for (; gr < nb_granules; gr++) {

  1399.         for (ch = 0; ch < s->nb_channels; ch++) {

  1400.             g = &s->granules[ch][gr];

  1401.             bits_pos = get_bits_count(&s->gb);

  1402. 

  1403.             if (!s->lsf) {

  1404.                 uint8_t *sc;

  1405.                 int slen, slen1, slen2;

  1406. 

  1407.                 /* MPEG1 scale factors */

  1408.                 slen1 = slen_table[0][g->scalefac_compress];

  1409.                 slen2 = slen_table[1][g->scalefac_compress];

  1410.                 av_dlog(s->avctx, "slen1=%d slen2=%d\n", slen1, slen2);

  1411.                 if (g->block_type == 2) {

  1412.                     n = g->switch_point ? 17 : 18;

  1413.                     j = 0;

  1414.                     if (slen1) {

  1415.                         for (i = 0; i < n; i++)

  1416.                             g->scale_factors[j++] = get_bits(&s->gb, slen1);

  1417.                     } else {

  1418.                         for (i = 0; i < n; i++)

  1419.                             g->scale_factors[j++] = 0;

  1420.                     }

  1421.                     if (slen2) {

  1422.                         for (i = 0; i < 18; i++)

  1423.                             g->scale_factors[j++] = get_bits(&s->gb, slen2);

  1424.                         for (i = 0; i < 3; i++)

  1425.                             g->scale_factors[j++] = 0;

  1426.                     } else {

  1427.                         for (i = 0; i < 21; i++)

  1428.                             g->scale_factors[j++] = 0;

  1429.                     }

  1430.                 } else {

  1431.                     sc = s->granules[ch][0].scale_factors;

  1432.                     j = 0;

  1433.                     for (k = 0; k < 4; k++) {

  1434.                         n = k == 0 ? 6 : 5;

  1435.                         if ((g->scfsi & (0x8 >> k)) == 0) {

  1436.                             slen = (k < 2) ? slen1 : slen2;

  1437.                             if (slen) {

  1438.                                 for (i = 0; i < n; i++)

  1439.                                     g->scale_factors[j++] = get_bits(&s->gb, slen);

  1440.                             } else {

  1441.                                 for (i = 0; i < n; i++)

  1442.                                     g->scale_factors[j++] = 0;

  1443.                             }

  1444.                         } else {

  1445.                             /* simply copy from last granule */

  1446.                             for (i = 0; i < n; i++) {

  1447.                                 g->scale_factors[j] = sc[j];

  1448.                                 j++;

  1449.                             }

  1450.                         }

  1451.                     }

  1452.                     g->scale_factors[j++] = 0;

  1453.                 }

  1454.             } else {

  1455.                 int tindex, tindex2, slen[4], sl, sf;

  1456. 

  1457.                 /* LSF scale factors */

  1458.                 if (g->block_type == 2)

  1459.                     tindex = g->switch_point ? 2 : 1;

  1460.                 else

  1461.                     tindex = 0;

  1462. 

  1463.                 sf = g->scalefac_compress;

  1464.                 if ((s->mode_ext & MODE_EXT_I_STEREO) && ch == 1) {

  1465.                     /* intensity stereo case */

  1466.                     sf >>= 1;

  1467.                     if (sf < 180) {

  1468.                         lsf_sf_expand(slen, sf, 6, 6, 0);

  1469.                         tindex2 = 3;

  1470.                     } else if (sf < 244) {

  1471.                         lsf_sf_expand(slen, sf - 180, 4, 4, 0);

  1472.                         tindex2 = 4;

  1473.                     } else {

  1474.                         lsf_sf_expand(slen, sf - 244, 3, 0, 0);

  1475.                         tindex2 = 5;

  1476.                     }

  1477.                 } else {

  1478.                     /* normal case */

  1479.                     if (sf < 400) {

  1480.                         lsf_sf_expand(slen, sf, 5, 4, 4);

  1481.                         tindex2 = 0;

  1482.                     } else if (sf < 500) {

  1483.                         lsf_sf_expand(slen, sf - 400, 5, 4, 0);

  1484.                         tindex2 = 1;

  1485.                     } else {

  1486.                         lsf_sf_expand(slen, sf - 500, 3, 0, 0);

  1487.                         tindex2 = 2;

  1488.                         g->preflag = 1;

  1489.                     }

  1490.                 }

  1491. 

  1492.                 j = 0;

  1493.                 for (k = 0; k < 4; k++) {

  1494.                     n  = lsf_nsf_table[tindex2][tindex][k];

  1495.                     sl = slen[k];

  1496.                     if (sl) {

  1497.                         for (i = 0; i < n; i++)

  1498.                             g->scale_factors[j++] = get_bits(&s->gb, sl);

  1499.                     } else {

  1500.                         for (i = 0; i < n; i++)

  1501.                             g->scale_factors[j++] = 0;

  1502.                     }

  1503.                 }

  1504.                 /* XXX: should compute exact size */

  1505.                 for (; j < 40; j++)

  1506.                     g->scale_factors[j] = 0;

  1507.             }

  1508. 

  1509.             exponents_from_scale_factors(s, g, exponents);

  1510. 

  1511.             /* read Huffman coded residue */

  1512.             huffman_decode(s, g, exponents, bits_pos + g->part2_3_length);

  1513.         } /* ch */

  1514. 

  1515.         if (s->mode == MPA_JSTEREO)

  1516.             compute_stereo(s, &s->granules[0][gr], &s->granules[1][gr]);

  1517. 

  1518.         for (ch = 0; ch < s->nb_channels; ch++) {

  1519.             g = &s->granules[ch][gr];

  1520. 

  1521.             reorder_block(s, g);

  1522.             compute_antialias(s, g);

  1523.             compute_imdct(s, g, &s->sb_samples[ch][18 * gr][0], s->mdct_buf[ch]);

  1524.         }

  1525.     } /* gr */

  1526.     if (get_bits_count(&s->gb) < 0)

  1527.         skip_bits_long(&s->gb, -get_bits_count(&s->gb));

  1528.     return nb_granules * 18;

  1529. }

  1530. 

  1531. static int mp_decode_frame(MPADecodeContext *s, OUT_INT **samples,

  1532.                            const uint8_t *buf, int buf_size)

  1533. {

  1534.     int i, nb_frames, ch, ret;

  1535.     OUT_INT *samples_ptr;

  1536. 

  1537.     init_get_bits(&s->gb, buf + HEADER_SIZE, (buf_size - HEADER_SIZE) * 8);

  1538. 

  1539.     /* skip error protection field */

  1540.     if (s->error_protection)

  1541.         skip_bits(&s->gb, 16);

  1542. 

  1543.     switch(s->layer) {

  1544.     case 1:

  1545.         s->avctx->frame_size = 384;

  1546.         nb_frames = mp_decode_layer1(s);

  1547.         break;

  1548.     case 2:

  1549.         s->avctx->frame_size = 1152;

  1550.         nb_frames = mp_decode_layer2(s);

  1551.         break;

  1552.     case 3:

  1553.         s->avctx->frame_size = s->lsf ? 576 : 1152;

  1554.     default:

  1555.         nb_frames = mp_decode_layer3(s);

  1556. 

  1557.         if (nb_frames < 0)

  1558.             return nb_frames;

  1559. 

  1560.         s->last_buf_size=0;

  1561.         if (s->in_gb.buffer) {

  1562.             align_get_bits(&s->gb);

  1563.             i = get_bits_left(&s->gb)>>3;

  1564.             if (i >= 0 && i <= BACKSTEP_SIZE) {

  1565.                 memmove(s->last_buf, s->gb.buffer + (get_bits_count(&s->gb)>>3), i);

  1566.                 s->last_buf_size=i;

  1567.             } else

  1568.                 av_log(s->avctx, AV_LOG_ERROR, "invalid old backstep %d\n", i);

  1569.             s->gb           = s->in_gb;

  1570.             s->in_gb.buffer = NULL;

  1571.         }

  1572. 

  1573.         align_get_bits(&s->gb);

  1574.         assert((get_bits_count(&s->gb) & 7) == 0);

  1575.         i = get_bits_left(&s->gb) >> 3;

  1576. 

  1577.         if (i < 0 || i > BACKSTEP_SIZE || nb_frames < 0) {

  1578.             if (i < 0)

  1579.                 av_log(s->avctx, AV_LOG_ERROR, "invalid new backstep %d\n", i);

  1580.             i = FFMIN(BACKSTEP_SIZE, buf_size - HEADER_SIZE);

  1581.         }

  1582.         assert(i <= buf_size - HEADER_SIZE && i >= 0);

  1583.         memcpy(s->last_buf + s->last_buf_size, s->gb.buffer + buf_size - HEADER_SIZE - i, i);

  1584.         s->last_buf_size += i;

  1585.     }

  1586. 

  1587.     /* get output buffer */

  1588.     if (!samples) {

  1589.         av_assert0(s->frame != NULL);

  1590.         s->frame->nb_samples = s->avctx->frame_size;

  1591.         if ((ret = ff_get_buffer(s->avctx, s->frame, 0)) < 0) {

  1592.             av_log(s->avctx, AV_LOG_ERROR, "get_buffer() failed\n");

  1593.             return ret;

  1594.         }

  1595.         samples = (OUT_INT **)s->frame->extended_data;

  1596.     }

  1597. 

  1598.     /* apply the synthesis filter */

  1599.     for (ch = 0; ch < s->nb_channels; ch++) {

  1600.         int sample_stride;

  1601.         if (s->avctx->sample_fmt == OUT_FMT_P) {

  1602.             samples_ptr   = samples[ch];

  1603.             sample_stride = 1;

  1604.         } else {

  1605.             samples_ptr   = samples[0] + ch;

  1606.             sample_stride = s->nb_channels;

  1607.         }

  1608.         for (i = 0; i < nb_frames; i++) {

  1609.             RENAME(ff_mpa_synth_filter)(&s->mpadsp, s->synth_buf[ch],

  1610.                                         &(s->synth_buf_offset[ch]),

  1611.                                         RENAME(ff_mpa_synth_window),

  1612.                                         &s->dither_state, samples_ptr,

  1613.                                         sample_stride, s->sb_samples[ch][i]);

  1614.             samples_ptr += 32 * sample_stride;

  1615.         }

  1616.     }

  1617. 

  1618.     return nb_frames * 32 * sizeof(OUT_INT) * s->nb_channels;

  1619. }

  1620. 

  1621. static int decode_frame(AVCodecContext * avctx, void *data, int *got_frame_ptr,

  1622.                         AVPacket *avpkt)

  1623. {

  1624.     const uint8_t *buf  = avpkt->data;

  1625.     int buf_size        = avpkt->size;

  1626.     MPADecodeContext *s = avctx->priv_data;

  1627.     uint32_t header;

  1628.     int ret;

  1629. 

  1630.     if (buf_size < HEADER_SIZE)

  1631.         return AVERROR_INVALIDDATA;

  1632. 

  1633.     header = AV_RB32(buf);

  1634.     if (ff_mpa_check_header(header) < 0) {

  1635.         av_log(avctx, AV_LOG_ERROR, "Header missing\n");

  1636.         return AVERROR_INVALIDDATA;

  1637.     }

  1638. 

  1639.     if (avpriv_mpegaudio_decode_header((MPADecodeHeader *)s, header) == 1) {

  1640.         /* free format: prepare to compute frame size */

  1641.         s->frame_size = -1;

  1642.         return AVERROR_INVALIDDATA;

  1643.     }

  1644.     /* update codec info */

  1645.     avctx->channels       = s->nb_channels;

  1646.     avctx->channel_layout = s->nb_channels == 1 ? AV_CH_LAYOUT_MONO : AV_CH_LAYOUT_STEREO;

  1647.     if (!avctx->bit_rate)

  1648.         avctx->bit_rate = s->bit_rate;

  1649. 

  1650.     if (s->frame_size <= 0 || s->frame_size > buf_size) {

  1651.         av_log(avctx, AV_LOG_ERROR, "incomplete frame\n");

  1652.         return AVERROR_INVALIDDATA;

  1653.     } else if (s->frame_size < buf_size) {

  1654.         buf_size= s->frame_size;

  1655.     }

  1656. 

  1657.     s->frame = data;

  1658. 

  1659.     ret = mp_decode_frame(s, NULL, buf, buf_size);

  1660.     if (ret >= 0) {

  1661.         s->frame->nb_samples = avctx->frame_size;

  1662.         *got_frame_ptr       = 1;

  1663.         avctx->sample_rate   = s->sample_rate;

  1664.         //FIXME maybe move the other codec info stuff from above here too

  1665.     } else {

  1666.         av_log(avctx, AV_LOG_ERROR, "Error while decoding MPEG audio frame.\n");

  1667.         /* Only return an error if the bad frame makes up the whole packet or

  1668.          * the error is related to buffer management.

  1669.          * If there is more data in the packet, just consume the bad frame

  1670.          * instead of returning an error, which would discard the whole

  1671.          * packet. */

  1672.         *got_frame_ptr = 0;

  1673.         if (buf_size == avpkt->size || ret != AVERROR_INVALIDDATA)

  1674.             return ret;

  1675.     }

  1676.     s->frame_size = 0;

  1677.     return buf_size;

  1678. }

  1679. 

  1680. static void mp_flush(MPADecodeContext *ctx)

  1681. {

  1682.     memset(ctx->synth_buf, 0, sizeof(ctx->synth_buf));

  1683.     ctx->last_buf_size = 0;

  1684. }

  1685. 

  1686. static void flush(AVCodecContext *avctx)

  1687. {

  1688.     mp_flush(avctx->priv_data);

  1689. }

  1690. 

  1691. #if CONFIG_MP3ADU_DECODER || CONFIG_MP3ADUFLOAT_DECODER

  1692. static int decode_frame_adu(AVCodecContext *avctx, void *data,

  1693.                             int *got_frame_ptr, AVPacket *avpkt)

  1694. {

  1695.     const uint8_t *buf  = avpkt->data;

  1696.     int buf_size        = avpkt->size;

  1697.     MPADecodeContext *s = avctx->priv_data;

  1698.     uint32_t header;

  1699.     int len, ret;

  1700. 

  1701.     len = buf_size;

  1702. 

  1703.     // Discard too short frames

  1704.     if (buf_size < HEADER_SIZE) {

  1705.         av_log(avctx, AV_LOG_ERROR, "Packet is too small\n");

  1706.         return AVERROR_INVALIDDATA;

  1707.     }

  1708. 

  1709. 

  1710.     if (len > MPA_MAX_CODED_FRAME_SIZE)

  1711.         len = MPA_MAX_CODED_FRAME_SIZE;

  1712. 

  1713.     // Get header and restore sync word

  1714.     header = AV_RB32(buf) | 0xffe00000;

  1715. 

  1716.     if (ff_mpa_check_header(header) < 0) { // Bad header, discard frame

  1717.         av_log(avctx, AV_LOG_ERROR, "Invalid frame header\n");

  1718.         return AVERROR_INVALIDDATA;

  1719.     }

  1720. 

  1721.     avpriv_mpegaudio_decode_header((MPADecodeHeader *)s, header);

  1722.     /* update codec info */

  1723.     avctx->sample_rate = s->sample_rate;

  1724.     avctx->channels    = s->nb_channels;

  1725.     avctx->channel_layout = s->nb_channels == 1 ? AV_CH_LAYOUT_MONO : AV_CH_LAYOUT_STEREO;

  1726.     if (!avctx->bit_rate)

  1727.         avctx->bit_rate = s->bit_rate;

  1728. 

  1729.     s->frame_size = len;

  1730. 

  1731.     s->frame = data;

  1732. 

  1733.     ret = mp_decode_frame(s, NULL, buf, buf_size);

  1734.     if (ret < 0) {

  1735.         av_log(avctx, AV_LOG_ERROR, "Error while decoding MPEG audio frame.\n");

  1736.         return ret;

  1737.     }

  1738. 

  1739.     *got_frame_ptr = 1;

  1740. 

  1741.     return buf_size;

  1742. }

  1743. #endif /* CONFIG_MP3ADU_DECODER || CONFIG_MP3ADUFLOAT_DECODER */

  1744. 

  1745. #if CONFIG_MP3ON4_DECODER || CONFIG_MP3ON4FLOAT_DECODER

  1746. 

  1747. /**

  1748.  * Context for MP3On4 decoder

  1749.  */

  1750. typedef struct MP3On4DecodeContext {

  1751.     int frames;                     ///< number of mp3 frames per block (number of mp3 decoder instances)

  1752.     int syncword;                   ///< syncword patch

  1753.     const uint8_t *coff;            ///< channel offsets in output buffer

  1754.     MPADecodeContext *mp3decctx[5]; ///< MPADecodeContext for every decoder instance

  1755. } MP3On4DecodeContext;

  1756. 

  1757. #include "mpeg4audio.h"

  1758. 

  1759. /* Next 3 arrays are indexed by channel config number (passed via codecdata) */

  1760. 

  1761. /* number of mp3 decoder instances */

  1762. static const uint8_t mp3Frames[8] = { 0, 1, 1, 2, 3, 3, 4, 5 };

  1763. 

  1764. /* offsets into output buffer, assume output order is FL FR C LFE BL BR SL SR */

  1765. static const uint8_t chan_offset[8][5] = {

  1766.     { 0             },

  1767.     { 0             },  // C

  1768.     { 0             },  // FLR

  1769.     { 2, 0          },  // C FLR

  1770.     { 2, 0, 3       },  // C FLR BS

  1771.     { 2, 0, 3       },  // C FLR BLRS

  1772.     { 2, 0, 4, 3    },  // C FLR BLRS LFE

  1773.     { 2, 0, 6, 4, 3 },  // C FLR BLRS BLR LFE

  1774. };

  1775. 

  1776. /* mp3on4 channel layouts */

  1777. static const int16_t chan_layout[8] = {

  1778.     0,

  1779.     AV_CH_LAYOUT_MONO,

  1780.     AV_CH_LAYOUT_STEREO,

  1781.     AV_CH_LAYOUT_SURROUND,

  1782.     AV_CH_LAYOUT_4POINT0,

  1783.     AV_CH_LAYOUT_5POINT0,

  1784.     AV_CH_LAYOUT_5POINT1,

  1785.     AV_CH_LAYOUT_7POINT1

  1786. };

  1787. 

  1788. static av_cold int decode_close_mp3on4(AVCodecContext * avctx)

  1789. {

  1790.     MP3On4DecodeContext *s = avctx->priv_data;

  1791.     int i;

  1792. 

  1793.     for (i = 0; i < s->frames; i++)

  1794.         av_free(s->mp3decctx[i]);

  1795. 

  1796.     return 0;

  1797. }

  1798. 

  1799. 

  1800. static av_cold int decode_init_mp3on4(AVCodecContext * avctx)

  1801. {

  1802.     MP3On4DecodeContext *s = avctx->priv_data;

  1803.     MPEG4AudioConfig cfg;

  1804.     int i;

  1805. 

  1806.     if ((avctx->extradata_size < 2) || (avctx->extradata == NULL)) {

  1807.         av_log(avctx, AV_LOG_ERROR, "Codec extradata missing or too short.\n");

  1808.         return AVERROR_INVALIDDATA;

  1809.     }

  1810. 

  1811.     avpriv_mpeg4audio_get_config(&cfg, avctx->extradata,

  1812.                                  avctx->extradata_size * 8, 1);

  1813.     if (!cfg.chan_config || cfg.chan_config > 7) {

  1814.         av_log(avctx, AV_LOG_ERROR, "Invalid channel config number.\n");

  1815.         return AVERROR_INVALIDDATA;

  1816.     }

  1817.     s->frames             = mp3Frames[cfg.chan_config];

  1818.     s->coff               = chan_offset[cfg.chan_config];

  1819.     avctx->channels       = ff_mpeg4audio_channels[cfg.chan_config];

  1820.     avctx->channel_layout = chan_layout[cfg.chan_config];

  1821. 

  1822.     if (cfg.sample_rate < 16000)

  1823.         s->syncword = 0xffe00000;

  1824.     else

  1825.         s->syncword = 0xfff00000;

  1826. 

  1827.     /* Init the first mp3 decoder in standard way, so that all tables get builded

  1828.      * We replace avctx->priv_data with the context of the first decoder so that

  1829.      * decode_init() does not have to be changed.

  1830.      * Other decoders will be initialized here copying data from the first context

  1831.      */

  1832.     // Allocate zeroed memory for the first decoder context

  1833.     s->mp3decctx[0] = av_mallocz(sizeof(MPADecodeContext));

  1834.     if (!s->mp3decctx[0])

  1835.         goto alloc_fail;

  1836.     // Put decoder context in place to make init_decode() happy

  1837.     avctx->priv_data = s->mp3decctx[0];

  1838.     decode_init(avctx);

  1839.     // Restore mp3on4 context pointer

  1840.     avctx->priv_data = s;

  1841.     s->mp3decctx[0]->adu_mode = 1; // Set adu mode

  1842. 

  1843.     /* Create a separate codec/context for each frame (first is already ok).

  1844.      * Each frame is 1 or 2 channels - up to 5 frames allowed

  1845.      */

  1846.     for (i = 1; i < s->frames; i++) {

  1847.         s->mp3decctx[i] = av_mallocz(sizeof(MPADecodeContext));

  1848.         if (!s->mp3decctx[i])

  1849.             goto alloc_fail;

  1850.         s->mp3decctx[i]->adu_mode = 1;

  1851.         s->mp3decctx[i]->avctx = avctx;

  1852.         s->mp3decctx[i]->mpadsp = s->mp3decctx[0]->mpadsp;

  1853.     }

  1854. 

  1855.     return 0;

  1856. alloc_fail:

  1857.     decode_close_mp3on4(avctx);

  1858.     return AVERROR(ENOMEM);

  1859. }

  1860. 

  1861. 

  1862. static void flush_mp3on4(AVCodecContext *avctx)

  1863. {

  1864.     int i;

  1865.     MP3On4DecodeContext *s = avctx->priv_data;

  1866. 

  1867.     for (i = 0; i < s->frames; i++)

  1868.         mp_flush(s->mp3decctx[i]);

  1869. }

  1870. 

  1871. 

  1872. static int decode_frame_mp3on4(AVCodecContext *avctx, void *data,

  1873.                                int *got_frame_ptr, AVPacket *avpkt)

  1874. {

  1875.     AVFrame *frame         = data;

  1876.     const uint8_t *buf     = avpkt->data;

  1877.     int buf_size           = avpkt->size;

  1878.     MP3On4DecodeContext *s = avctx->priv_data;

  1879.     MPADecodeContext *m;

  1880.     int fsize, len = buf_size, out_size = 0;

  1881.     uint32_t header;

  1882.     OUT_INT **out_samples;

  1883.     OUT_INT *outptr[2];

  1884.     int fr, ch, ret;

  1885. 

  1886.     /* get output buffer */

  1887.     frame->nb_samples = MPA_FRAME_SIZE;

  1888.     if ((ret = ff_get_buffer(avctx, frame, 0)) < 0) {

  1889.         av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");

  1890.         return ret;

  1891.     }

  1892.     out_samples = (OUT_INT **)frame->extended_data;

  1893. 

  1894.     // Discard too short frames

  1895.     if (buf_size < HEADER_SIZE)

  1896.         return AVERROR_INVALIDDATA;

  1897. 

  1898.     avctx->bit_rate = 0;

  1899. 

  1900.     ch = 0;

  1901.     for (fr = 0; fr < s->frames; fr++) {

  1902.         fsize = AV_RB16(buf) >> 4;

  1903.         fsize = FFMIN3(fsize, len, MPA_MAX_CODED_FRAME_SIZE);

  1904.         m     = s->mp3decctx[fr];

  1905.         assert(m != NULL);

  1906. 

  1907.         if (fsize < HEADER_SIZE) {

  1908.             av_log(avctx, AV_LOG_ERROR, "Frame size smaller than header size\n");

  1909.             return AVERROR_INVALIDDATA;

  1910.         }

  1911.         header = (AV_RB32(buf) & 0x000fffff) | s->syncword; // patch header

  1912. 

  1913.         if (ff_mpa_check_header(header) < 0) // Bad header, discard block

  1914.             break;

  1915. 

  1916.         avpriv_mpegaudio_decode_header((MPADecodeHeader *)m, header);

  1917. 

  1918.         if (ch + m->nb_channels > avctx->channels ||

  1919.             s->coff[fr] + m->nb_channels > avctx->channels) {

  1920.             av_log(avctx, AV_LOG_ERROR, "frame channel count exceeds codec "

  1921.                                         "channel count\n");

  1922.             return AVERROR_INVALIDDATA;

  1923.         }

  1924.         ch += m->nb_channels;

  1925. 

  1926.         outptr[0] = out_samples[s->coff[fr]];

  1927.         if (m->nb_channels > 1)

  1928.             outptr[1] = out_samples[s->coff[fr] + 1];

  1929. 

  1930.         if ((ret = mp_decode_frame(m, outptr, buf, fsize)) < 0)

  1931.             return ret;

  1932. 

  1933.         out_size += ret;

  1934.         buf      += fsize;

  1935.         len      -= fsize;

  1936. 

  1937.         avctx->bit_rate += m->bit_rate;

  1938.     }

  1939. 

  1940.     /* update codec info */

  1941.     avctx->sample_rate = s->mp3decctx[0]->sample_rate;

  1942. 

  1943.     frame->nb_samples = out_size / (avctx->channels * sizeof(OUT_INT));

  1944.     *got_frame_ptr    = 1;

  1945. 

  1946.     return buf_size;

  1947. }

  1948. #endif /* CONFIG_MP3ON4_DECODER || CONFIG_MP3ON4FLOAT_DECODER */