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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/float_dsp.h"

  31. #include "libavutil/libm.h"

  32. #include "avcodec.h"

  33. #include "get_bits.h"

  34. #include "internal.h"

  35. #include "mathops.h"

  36. #include "mpegaudiodsp.h"

  37. 

  38. /*

  39.  * TODO:

  40.  *  - test lsf / mpeg25 extensively.

  41.  */

  42. 

  43. #include "mpegaudio.h"

  44. #include "mpegaudiodecheader.h"

  45. 

  46. #define BACKSTEP_SIZE 512

  47. #define EXTRABYTES 24

  48. #define LAST_BUF_SIZE 2 * BACKSTEP_SIZE + EXTRABYTES

  49. 

  50. /* layer 3 "granule" */

  51. typedef struct GranuleDef {

  52.     uint8_t scfsi;

  53.     int part2_3_length;

  54.     int big_values;

  55.     int global_gain;

  56.     int scalefac_compress;

  57.     uint8_t block_type;

  58.     uint8_t switch_point;

  59.     int table_select[3];

  60.     int subblock_gain[3];

  61.     uint8_t scalefac_scale;

  62.     uint8_t count1table_select;

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

  64.     int preflag;

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

  66.     uint8_t scale_factors[40];

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

  68. } GranuleDef;

  69. 

  70. typedef struct MPADecodeContext {

  71.     MPA_DECODE_HEADER

  72.     uint8_t last_buf[LAST_BUF_SIZE];

  73.     int last_buf_size;

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

  75.     uint32_t free_format_next_header;

  76.     GetBitContext gb;

  77.     GetBitContext in_gb;

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

  79.     int synth_buf_offset[MPA_MAX_CHANNELS];

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

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

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

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

  84.     int dither_state;

  85.     int err_recognition;

  86.     AVCodecContext* avctx;

  87.     MPADSPContext mpadsp;

  88.     AVFloatDSPContext fdsp;

  89.     AVFrame *frame;

  90. } MPADecodeContext;

  91. 

  92. #define HEADER_SIZE 4

  93. 

  94. #include "mpegaudiodata.h"

  95. #include "mpegaudiodectab.h"

  96. 

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

  98. static VLC huff_vlc[16];

  99. static VLC_TYPE huff_vlc_tables[

  100.     0 + 128 + 128 + 128 + 130 + 128 + 154 + 166 +

  101.   142 + 204 + 190 + 170 + 542 + 460 + 662 + 414

  102.   ][2];

  103. static const int huff_vlc_tables_sizes[16] = {

  104.     0,  128,  128,  128,  130,  128,  154,  166,

  105.   142,  204,  190,  170,  542,  460,  662,  414

  106. };

  107. static VLC huff_quad_vlc[2];

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

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

  110. /* computed from band_size_long */

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

  112. #include "mpegaudio_tablegen.h"

  113. /* intensity stereo coef table */

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

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

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

  117. 

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

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

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

  121. 

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

  123.     division_tab3, division_tab5, NULL, division_tab9

  124. };

  125. 

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

  127. static uint16_t scale_factor_modshift[64];

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

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

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

  131. 

  132. #define SCALE_GEN(v) \

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

  134. 

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

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

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

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

  139. };

  140. 

  141. /**

  142.  * Convert region offsets to region sizes and truncate

  143.  * size to big_values.

  144.  */

  145. static void region_offset2size(GranuleDef *g)

  146. {

  147.     int i, k, j = 0;

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

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

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

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

  152.         j = k;

  153.     }

  154. }

  155. 

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

  157. {

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

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

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

  161.         else

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

  163.     } else {

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

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

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

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

  168.         else

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

  170.     }

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

  172. }

  173. 

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

  175.                              int ra1, int ra2)

  176. {

  177.     int l;

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

  179.     /* should not overflow */

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

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

  182. }

  183. 

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

  185. {

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

  187.         if (g->switch_point) {

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

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

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

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

  192.                 exponents as long blocks */

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

  194.                 g->long_end = 8;

  195.             else

  196.                 g->long_end = 6;

  197. 

  198.             g->short_start = 3;

  199.         } else {

  200.             g->long_end    = 0;

  201.             g->short_start = 0;

  202.         }

  203.     } else {

  204.         g->short_start = 13;

  205.         g->long_end    = 22;

  206.     }

  207. }

  208. 

  209. /* layer 1 unscaling */

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

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

  212. {

  213.     int shift, mod;

  214.     int64_t val;

  215. 

  216.     shift   = scale_factor_modshift[scale_factor];

  217.     mod     = shift & 3;

  218.     shift >>= 2;

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

  220.     shift  += n;

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

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

  223. }

  224. 

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

  226. {

  227.     int shift, mod, val;

  228. 

  229.     shift   = scale_factor_modshift[scale_factor];

  230.     mod     = shift & 3;

  231.     shift >>= 2;

  232. 

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

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

  235.     if (shift > 0)

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

  237.     return val;

  238. }

  239. 

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

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

  242. {

  243.     unsigned int m;

  244.     int e;

  245. 

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

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

  248.     e -= exponent >> 2;

  249. #ifdef DEBUG

  250.     if(e < 1)

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

  252. #endif

  253.     if (e > 31)

  254.         return 0;

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

  256. 

  257.     return m;

  258. }

  259. 

  260. static av_cold void decode_init_static(void)

  261. {

  262.     int i, j, k;

  263.     int offset;

  264. 

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

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

  267.         int shift, mod;

  268.         /* 1.0 (i = 3) is normalized to 2 ^ FRAC_BITS */

  269.         shift = i / 3;

  270.         mod   = i % 3;

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

  272.     }

  273. 

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

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

  276.         int n, norm;

  277.         n = i + 2;

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

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

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

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

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

  283.                 scale_factor_mult[i][0],

  284.                 scale_factor_mult[i][1],

  285.                 scale_factor_mult[i][2]);

  286.     }

  287. 

  288.     RENAME(ff_mpa_synth_init)(RENAME(ff_mpa_synth_window));

  289. 

  290.     /* huffman decode tables */

  291.     offset = 0;

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

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

  294.         int xsize, x, y;

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

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

  297. 

  298.         xsize = h->xsize;

  299. 

  300.         j = 0;

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

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

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

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

  305.             }

  306.         }

  307. 

  308.         /* XXX: fail test */

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

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

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

  312.                  tmp_bits, 1, 1, tmp_codes, 2, 2,

  313.                  INIT_VLC_USE_NEW_STATIC);

  314.         offset += huff_vlc_tables_sizes[i];

  315.     }

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

  317. 

  318.     offset = 0;

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

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

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

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

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

  324.                  INIT_VLC_USE_NEW_STATIC);

  325.         offset += huff_quad_vlc_tables_sizes[i];

  326.     }

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

  328. 

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

  330.         k = 0;

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

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

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

  334.         }

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

  336.     }

  337. 

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

  339. 

  340.     mpegaudio_tableinit();

  341. 

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

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

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

  345.                 int val1, val2, val3, steps;

  346.                 int val = j;

  347.                 steps   = ff_mpa_quant_steps[i];

  348.                 val1    = val % steps;

  349.                 val    /= steps;

  350.                 val2    = val % steps;

  351.                 val3    = val / steps;

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

  353.             }

  354.         }

  355.     }

  356. 

  357. 

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

  359.         float f;

  360.         INTFLOAT v;

  361.         if (i != 6) {

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

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

  364.         } else {

  365.             v = FIXR(1.0);

  366.         }

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

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

  369.     }

  370.     /* invalid values */

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

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

  373. 

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

  375.         double f;

  376.         int e, k;

  377. 

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

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

  380.             f = exp2(e / 4.0);

  381.             k = i & 1;

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

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

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

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

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

  387.         }

  388.     }

  389. 

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

  391.         float ci, cs, ca;

  392.         ci = ci_table[i];

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

  394.         ca = cs * ci;

  395. #if !USE_FLOATS

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

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

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

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

  400. #else

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

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

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

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

  405. #endif

  406.     }

  407. }

  408. 

  409. static av_cold int decode_init(AVCodecContext * avctx)

  410. {

  411.     static int initialized_tables = 0;

  412.     MPADecodeContext *s = avctx->priv_data;

  413. 

  414.     if (!initialized_tables) {

  415.         decode_init_static();

  416.         initialized_tables = 1;

  417.     }

  418. 

  419.     s->avctx = avctx;

  420. 

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

  422.     ff_mpadsp_init(&s->mpadsp);

  423. 

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

  425.         avctx->codec_id != AV_CODEC_ID_MP3ON4)

  426.         avctx->sample_fmt = OUT_FMT;

  427.     else

  428.         avctx->sample_fmt = OUT_FMT_P;

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

  430. 

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

  432.         s->adu_mode = 1;

  433. 

  434.     return 0;

  435. }

  436. 

  437. #define C3 FIXHR(0.86602540378443864676/2)

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

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

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

  441. 

  442. /* 12 points IMDCT. We compute it "by hand" by factorizing obvious

  443.    cases. */

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

  445. {

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

  447. 

  448.     in0  = in[0*3];

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

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

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

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

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

  454.     in5 += in3;

  455.     in3 += in1;

  456. 

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

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

  459. 

  460.     t1   = in0 - in4;

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

  462. 

  463.     out[ 7] =

  464.     out[10] = t1 + t2;

  465.     out[ 1] =

  466.     out[ 4] = t1 - t2;

  467. 

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

  469.     in4     = in0 + in2;

  470.     in5    += 2*in1;

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

  472.     out[ 8] =

  473.     out[ 9] = in4 + in1;

  474.     out[ 2] =

  475.     out[ 3] = in4 - in1;

  476. 

  477.     in0    -= in2;

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

  479.     out[ 0] =

  480.     out[ 5] = in0 - in5;

  481.     out[ 6] =

  482.     out[11] = in0 + in5;

  483. }

  484. 

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

  486. static int mp_decode_layer1(MPADecodeContext *s)

  487. {

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

  489.     uint8_t allocation[MPA_MAX_CHANNELS][SBLIMIT];

  490.     uint8_t scale_factors[MPA_MAX_CHANNELS][SBLIMIT];

  491. 

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

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

  494.     else

  495.         bound = SBLIMIT;

  496. 

  497.     /* allocation bits */

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

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

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

  501.         }

  502.     }

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

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

  505. 

  506.     /* scale factors */

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

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

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

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

  511.         }

  512.     }

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

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

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

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

  517.         }

  518.     }

  519. 

  520.     /* compute samples */

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

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

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

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

  525.                 if (n) {

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

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

  528.                 } else {

  529.                     v = 0;

  530.                 }

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

  532.             }

  533.         }

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

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

  536.             if (n) {

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

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

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

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

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

  542.             } else {

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

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

  545.             }

  546.         }

  547.     }

  548.     return 12;

  549. }

  550. 

  551. static int mp_decode_layer2(MPADecodeContext *s)

  552. {

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

  554.     const unsigned char *alloc_table;

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

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

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

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

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

  560. 

  561.     /* select decoding table */

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

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

  564.     sblimit     = ff_mpa_sblimit_table[table];

  565.     alloc_table = ff_mpa_alloc_tables[table];

  566. 

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

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

  569.     else

  570.         bound = sblimit;

  571. 

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

  573. 

  574.     /* sanity check */

  575.     if (bound > sblimit)

  576.         bound = sblimit;

  577. 

  578.     /* parse bit allocation */

  579.     j = 0;

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

  581.         bit_alloc_bits = alloc_table[j];

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

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

  584.         j += 1 << bit_alloc_bits;

  585.     }

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

  587.         bit_alloc_bits = alloc_table[j];

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

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

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

  591.         j += 1 << bit_alloc_bits;

  592.     }

  593. 

  594.     /* scale codes */

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

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

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

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

  599.         }

  600.     }

  601. 

  602.     /* scale factors */

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

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

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

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

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

  608.                 default:

  609.                 case 0:

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

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

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

  613.                     break;

  614.                 case 2:

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

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

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

  618.                     break;

  619.                 case 1:

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

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

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

  623.                     break;

  624.                 case 3:

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

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

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

  628.                     break;

  629.                 }

  630.             }

  631.         }

  632.     }

  633. 

  634.     /* samples */

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

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

  637.             j = 0;

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

  639.                 bit_alloc_bits = alloc_table[j];

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

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

  642.                     if (b) {

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

  644.                         qindex = alloc_table[j+b];

  645.                         bits = ff_mpa_quant_bits[qindex];

  646.                         if (bits < 0) {

  647.                             int v2;

  648.                             /* 3 values at the same time */

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

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

  651.                             steps  = ff_mpa_quant_steps[qindex];

  652. 

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

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

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

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

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

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

  659.                         } else {

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

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

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

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

  664.                             }

  665.                         }

  666.                     } else {

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

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

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

  670.                     }

  671.                 }

  672.                 /* next subband in alloc table */

  673.                 j += 1 << bit_alloc_bits;

  674.             }

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

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

  677.                 bit_alloc_bits = alloc_table[j];

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

  679.                 if (b) {

  680.                     int mant, scale0, scale1;

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

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

  683.                     qindex = alloc_table[j+b];

  684.                     bits = ff_mpa_quant_bits[qindex];

  685.                     if (bits < 0) {

  686.                         /* 3 values at the same time */

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

  688.                         steps = ff_mpa_quant_steps[qindex];

  689.                         mant = v % steps;

  690.                         v = v / steps;

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

  692.                             l2_unscale_group(steps, mant, scale0);

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

  694.                             l2_unscale_group(steps, mant, scale1);

  695.                         mant = v % steps;

  696.                         v = v / steps;

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

  698.                             l2_unscale_group(steps, mant, scale0);

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

  700.                             l2_unscale_group(steps, mant, scale1);

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

  702.                             l2_unscale_group(steps, v, scale0);

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

  704.                             l2_unscale_group(steps, v, scale1);

  705.                     } else {

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

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

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

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

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

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

  712.                         }

  713.                     }

  714.                 } else {

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

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

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

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

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

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

  721.                 }

  722.                 /* next subband in alloc table */

  723.                 j += 1 << bit_alloc_bits;

  724.             }

  725.             /* fill remaining samples to zero */

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

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

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

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

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

  731.                 }

  732.             }

  733.         }

  734.     }

  735.     return 3 * 12;

  736. }

  737. 

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

  739.     if (n == 3) {                   \

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

  741.         dst   = sf - 3 * m;         \

  742.         sf    = m;                  \

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

  744.         dst  = sf & 3;              \

  745.         sf >>= 2;                   \

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

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

  748.         dst   = sf - 5 * m;         \

  749.         sf    = m;                  \

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

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

  752.         dst   = sf - 6 * m;         \

  753.         sf    = m;                  \

  754.     } else {                        \

  755.         dst = 0;                    \

  756.     }

  757. 

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

  759.                                            int n3)

  760. {

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

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

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

  764.     slen[0] = sf;

  765. }

  766. 

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

  768.                                          int16_t *exponents)

  769. {

  770.     const uint8_t *bstab, *pretab;

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

  772.     int16_t *exp_ptr;

  773. 

  774.     exp_ptr = exponents;

  775.     gain    = g->global_gain - 210;

  776.     shift   = g->scalefac_scale + 1;

  777. 

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

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

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

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

  782.         len = bstab[i];

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

  784.             *exp_ptr++ = v0;

  785.     }

  786. 

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

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

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

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

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

  792.         k        = g->long_end;

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

  794.             len = bstab[i];

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

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

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

  798.                     *exp_ptr++ = v0;

  799.             }

  800.         }

  801.     }

  802. }

  803. 

  804. /* handle n = 0 too */

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

  806. {

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

  808. }

  809. 

  810. 

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

  812.                           int *end_pos2)

  813. {

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

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

  816.         s->in_gb.buffer = NULL;

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

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

  819.         *end_pos2 =

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

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

  822.     }

  823. }

  824. 

  825. /* Following is a optimized code for

  826.             INTFLOAT v = *src

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

  828.                 v = -v;

  829.             *dst = v;

  830. */

  831. #if USE_FLOATS

  832. #define READ_FLIP_SIGN(dst,src)                     \

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

  834.     AV_WN32A(dst, v);

  835. #else

  836. #define READ_FLIP_SIGN(dst,src)     \

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

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

  839. #endif

  840. 

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

  842.                           int16_t *exponents, int end_pos2)

  843. {

  844.     int s_index;

  845.     int i;

  846.     int last_pos, bits_left;

  847.     VLC *vlc;

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

  849. 

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

  851.     s_index = 0;

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

  853.         int j, k, l, linbits;

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

  855.         if (j == 0)

  856.             continue;

  857.         /* select vlc table */

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

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

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

  861.         vlc     = &huff_vlc[l];

  862. 

  863.         if (!l) {

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

  865.             s_index += 2 * j;

  866.             continue;

  867.         }

  868. 

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

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

  871.             int exponent, x, y;

  872.             int v;

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

  874. 

  875.             if (pos >= end_pos){

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

  877.                 if (pos >= end_pos)

  878.                     break;

  879.             }

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

  881. 

  882.             if (!y) {

  883.                 g->sb_hybrid[s_index  ] =

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

  885.                 s_index += 2;

  886.                 continue;

  887.             }

  888. 

  889.             exponent= exponents[s_index];

  890. 

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

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

  893.             if (y & 16) {

  894.                 x = y >> 5;

  895.                 y = y & 0x0f;

  896.                 if (x < 15) {

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

  898.                 } else {

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

  900.                     v  = l3_unscale(x, exponent);

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

  902.                         v = -v;

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

  904.                 }

  905.                 if (y < 15) {

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

  907.                 } else {

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

  909.                     v  = l3_unscale(y, exponent);

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

  911.                         v = -v;

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

  913.                 }

  914.             } else {

  915.                 x = y >> 5;

  916.                 y = y & 0x0f;

  917.                 x += y;

  918.                 if (x < 15) {

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

  920.                 } else {

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

  922.                     v  = l3_unscale(x, exponent);

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

  924.                         v = -v;

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

  926.                 }

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

  928.             }

  929.             s_index += 2;

  930.         }

  931.     }

  932. 

  933.     /* high frequencies */

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

  935.     last_pos = 0;

  936.     while (s_index <= 572) {

  937.         int pos, code;

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

  939.         if (pos >= end_pos) {

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

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

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

  943.                 s_index -= 4;

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

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

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

  947.                     s_index=0;

  948.                 break;

  949.             }

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

  951.             if (pos >= end_pos)

  952.                 break;

  953.         }

  954.         last_pos = pos;

  955. 

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

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

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

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

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

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

  962.         while (code) {

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

  964.             int v;

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

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

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

  968.         }

  969.         s_index += 4;

  970.     }

  971.     /* skip extension bits */

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

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

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

  975.         s_index=0;

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

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

  978.         s_index = 0;

  979.     }

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

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

  982. 

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

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

  985. 

  986.     return 0;

  987. }

  988. 

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

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

  991.    complicated */

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

  993. {

  994.     int i, j, len;

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

  996.     INTFLOAT tmp[576];

  997. 

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

  999.         return;

  1000. 

  1001.     if (g->switch_point) {

  1002.         if (s->sample_rate_index != 8)

  1003.             ptr = g->sb_hybrid + 36;

  1004.         else

  1005.             ptr = g->sb_hybrid + 72;

  1006.     } else {

  1007.         ptr = g->sb_hybrid;

  1008.     }

  1009. 

  1010.     for (i = g->short_start; i < 13; i++) {

  1011.         len  = band_size_short[s->sample_rate_index][i];

  1012.         ptr1 = ptr;

  1013.         dst  = tmp;

  1014.         for (j = len; j > 0; j--) {

  1015.             *dst++ = ptr[0*len];

  1016.             *dst++ = ptr[1*len];

  1017.             *dst++ = ptr[2*len];

  1018.             ptr++;

  1019.         }

  1020.         ptr += 2 * len;

  1021.         memcpy(ptr1, tmp, len * 3 * sizeof(*ptr1));

  1022.     }

  1023. }

  1024. 

  1025. #define ISQRT2 FIXR(0.70710678118654752440)

  1026. 

  1027. static void compute_stereo(MPADecodeContext *s, GranuleDef *g0, GranuleDef *g1)

  1028. {

  1029.     int i, j, k, l;

  1030.     int sf_max, sf, len, non_zero_found;

  1031.     INTFLOAT (*is_tab)[16], *tab0, *tab1, tmp0, tmp1, v1, v2;

  1032.     int non_zero_found_short[3];

  1033. 

  1034.     /* intensity stereo */

  1035.     if (s->mode_ext & MODE_EXT_I_STEREO) {

  1036.         if (!s->lsf) {

  1037.             is_tab = is_table;

  1038.             sf_max = 7;

  1039.         } else {

  1040.             is_tab = is_table_lsf[g1->scalefac_compress & 1];

  1041.             sf_max = 16;

  1042.         }

  1043. 

  1044.         tab0 = g0->sb_hybrid + 576;

  1045.         tab1 = g1->sb_hybrid + 576;

  1046. 

  1047.         non_zero_found_short[0] = 0;

  1048.         non_zero_found_short[1] = 0;

  1049.         non_zero_found_short[2] = 0;

  1050.         k = (13 - g1->short_start) * 3 + g1->long_end - 3;

  1051.         for (i = 12; i >= g1->short_start; i--) {

  1052.             /* for last band, use previous scale factor */

  1053.             if (i != 11)

  1054.                 k -= 3;

  1055.             len = band_size_short[s->sample_rate_index][i];

  1056.             for (l = 2; l >= 0; l--) {

  1057.                 tab0 -= len;

  1058.                 tab1 -= len;

  1059.                 if (!non_zero_found_short[l]) {

  1060.                     /* test if non zero band. if so, stop doing i-stereo */

  1061.                     for (j = 0; j < len; j++) {

  1062.                         if (tab1[j] != 0) {

  1063.                             non_zero_found_short[l] = 1;

  1064.                             goto found1;

  1065.                         }

  1066.                     }

  1067.                     sf = g1->scale_factors[k + l];

  1068.                     if (sf >= sf_max)

  1069.                         goto found1;

  1070. 

  1071.                     v1 = is_tab[0][sf];

  1072.                     v2 = is_tab[1][sf];

  1073.                     for (j = 0; j < len; j++) {

  1074.                         tmp0    = tab0[j];

  1075.                         tab0[j] = MULLx(tmp0, v1, FRAC_BITS);

  1076.                         tab1[j] = MULLx(tmp0, v2, FRAC_BITS);

  1077.                     }

  1078.                 } else {

  1079. found1:

  1080.                     if (s->mode_ext & MODE_EXT_MS_STEREO) {

  1081.                         /* lower part of the spectrum : do ms stereo

  1082.                            if enabled */

  1083.                         for (j = 0; j < len; j++) {

  1084.                             tmp0    = tab0[j];

  1085.                             tmp1    = tab1[j];

  1086.                             tab0[j] = MULLx(tmp0 + tmp1, ISQRT2, FRAC_BITS);

  1087.                             tab1[j] = MULLx(tmp0 - tmp1, ISQRT2, FRAC_BITS);

  1088.                         }

  1089.                     }

  1090.                 }

  1091.             }

  1092.         }

  1093. 

  1094.         non_zero_found = non_zero_found_short[0] |

  1095.                          non_zero_found_short[1] |

  1096.                          non_zero_found_short[2];

  1097. 

  1098.         for (i = g1->long_end - 1;i >= 0;i--) {

  1099.             len   = band_size_long[s->sample_rate_index][i];

  1100.             tab0 -= len;

  1101.             tab1 -= len;

  1102.             /* test if non zero band. if so, stop doing i-stereo */

  1103.             if (!non_zero_found) {

  1104.                 for (j = 0; j < len; j++) {

  1105.                     if (tab1[j] != 0) {

  1106.                         non_zero_found = 1;

  1107.                         goto found2;

  1108.                     }

  1109.                 }

  1110.                 /* for last band, use previous scale factor */

  1111.                 k  = (i == 21) ? 20 : i;

  1112.                 sf = g1->scale_factors[k];

  1113.                 if (sf >= sf_max)

  1114.                     goto found2;

  1115.                 v1 = is_tab[0][sf];

  1116.                 v2 = is_tab[1][sf];

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

  1118.                     tmp0    = tab0[j];

  1119.                     tab0[j] = MULLx(tmp0, v1, FRAC_BITS);

  1120.                     tab1[j] = MULLx(tmp0, v2, FRAC_BITS);

  1121.                 }

  1122.             } else {

  1123. found2:

  1124.                 if (s->mode_ext & MODE_EXT_MS_STEREO) {

  1125.                     /* lower part of the spectrum : do ms stereo

  1126.                        if enabled */

  1127.                     for (j = 0; j < len; j++) {

  1128.                         tmp0    = tab0[j];

  1129.                         tmp1    = tab1[j];

  1130.                         tab0[j] = MULLx(tmp0 + tmp1, ISQRT2, FRAC_BITS);

  1131.                         tab1[j] = MULLx(tmp0 - tmp1, ISQRT2, FRAC_BITS);

  1132.                     }

  1133.                 }

  1134.             }

  1135.         }

  1136.     } else if (s->mode_ext & MODE_EXT_MS_STEREO) {

  1137.         /* ms stereo ONLY */

  1138.         /* NOTE: the 1/sqrt(2) normalization factor is included in the

  1139.            global gain */

  1140. #if USE_FLOATS

  1141.        s->fdsp.butterflies_float(g0->sb_hybrid, g1->sb_hybrid, 576);

  1142. #else

  1143.         tab0 = g0->sb_hybrid;

  1144.         tab1 = g1->sb_hybrid;

  1145.         for (i = 0; i < 576; i++) {

  1146.             tmp0    = tab0[i];

  1147.             tmp1    = tab1[i];

  1148.             tab0[i] = tmp0 + tmp1;

  1149.             tab1[i] = tmp0 - tmp1;

  1150.         }

  1151. #endif

  1152.     }

  1153. }

  1154. 

  1155. #if USE_FLOATS

  1156. #if HAVE_MIPSFPU

  1157. #   include "mips/compute_antialias_float.h"

  1158. #endif /* HAVE_MIPSFPU */

  1159. #else

  1160. #if HAVE_MIPSDSPR1

  1161. #   include "mips/compute_antialias_fixed.h"

  1162. #endif /* HAVE_MIPSDSPR1 */

  1163. #endif /* USE_FLOATS */

  1164. 

  1165. #ifndef compute_antialias

  1166. #if USE_FLOATS

  1167. #define AA(j) do {                                                      \

  1168.         float tmp0 = ptr[-1-j];                                         \

  1169.         float tmp1 = ptr[   j];                                         \

  1170.         ptr[-1-j] = tmp0 * csa_table[j][0] - tmp1 * csa_table[j][1];    \

  1171.         ptr[   j] = tmp0 * csa_table[j][1] + tmp1 * csa_table[j][0];    \

  1172.     } while (0)

  1173. #else

  1174. #define AA(j) do {                                              \

  1175.         int tmp0 = ptr[-1-j];                                   \

  1176.         int tmp1 = ptr[   j];                                   \

  1177.         int tmp2 = MULH(tmp0 + tmp1, csa_table[j][0]);          \

  1178.         ptr[-1-j] = 4 * (tmp2 - MULH(tmp1, csa_table[j][2]));   \

  1179.         ptr[   j] = 4 * (tmp2 + MULH(tmp0, csa_table[j][3]));   \

  1180.     } while (0)

  1181. #endif

  1182. 

  1183. static void compute_antialias(MPADecodeContext *s, GranuleDef *g)

  1184. {

  1185.     INTFLOAT *ptr;

  1186.     int n, i;

  1187. 

  1188.     /* we antialias only "long" bands */

  1189.     if (g->block_type == 2) {

  1190.         if (!g->switch_point)

  1191.             return;

  1192.         /* XXX: check this for 8000Hz case */

  1193.         n = 1;

  1194.     } else {

  1195.         n = SBLIMIT - 1;

  1196.     }

  1197. 

  1198.     ptr = g->sb_hybrid + 18;

  1199.     for (i = n; i > 0; i--) {

  1200.         AA(0);

  1201.         AA(1);

  1202.         AA(2);

  1203.         AA(3);

  1204.         AA(4);

  1205.         AA(5);

  1206.         AA(6);

  1207.         AA(7);

  1208. 

  1209.         ptr += 18;

  1210.     }

  1211. }

  1212. #endif /* compute_antialias */

  1213. 

  1214. static void compute_imdct(MPADecodeContext *s, GranuleDef *g,

  1215.                           INTFLOAT *sb_samples, INTFLOAT *mdct_buf)

  1216. {

  1217.     INTFLOAT *win, *out_ptr, *ptr, *buf, *ptr1;

  1218.     INTFLOAT out2[12];

  1219.     int i, j, mdct_long_end, sblimit;

  1220. 

  1221.     /* find last non zero block */

  1222.     ptr  = g->sb_hybrid + 576;

  1223.     ptr1 = g->sb_hybrid + 2 * 18;

  1224.     while (ptr >= ptr1) {

  1225.         int32_t *p;

  1226.         ptr -= 6;

  1227.         p    = (int32_t*)ptr;

  1228.         if (p[0] | p[1] | p[2] | p[3] | p[4] | p[5])

  1229.             break;

  1230.     }

  1231.     sblimit = ((ptr - g->sb_hybrid) / 18) + 1;

  1232. 

  1233.     if (g->block_type == 2) {

  1234.         /* XXX: check for 8000 Hz */

  1235.         if (g->switch_point)

  1236.             mdct_long_end = 2;

  1237.         else

  1238.             mdct_long_end = 0;

  1239.     } else {

  1240.         mdct_long_end = sblimit;

  1241.     }

  1242. 

  1243.     s->mpadsp.RENAME(imdct36_blocks)(sb_samples, mdct_buf, g->sb_hybrid,

  1244.                                      mdct_long_end, g->switch_point,

  1245.                                      g->block_type);

  1246. 

  1247.     buf = mdct_buf + 4*18*(mdct_long_end >> 2) + (mdct_long_end & 3);

  1248.     ptr = g->sb_hybrid + 18 * mdct_long_end;

  1249. 

  1250.     for (j = mdct_long_end; j < sblimit; j++) {

  1251.         /* select frequency inversion */

  1252.         win     = RENAME(ff_mdct_win)[2 + (4  & -(j & 1))];

  1253.         out_ptr = sb_samples + j;

  1254. 

  1255.         for (i = 0; i < 6; i++) {

  1256.             *out_ptr = buf[4*i];

  1257.             out_ptr += SBLIMIT;

  1258.         }

  1259.         imdct12(out2, ptr + 0);

  1260.         for (i = 0; i < 6; i++) {

  1261.             *out_ptr     = MULH3(out2[i    ], win[i    ], 1) + buf[4*(i + 6*1)];

  1262.             buf[4*(i + 6*2)] = MULH3(out2[i + 6], win[i + 6], 1);

  1263.             out_ptr += SBLIMIT;

  1264.         }

  1265.         imdct12(out2, ptr + 1);

  1266.         for (i = 0; i < 6; i++) {

  1267.             *out_ptr     = MULH3(out2[i    ], win[i    ], 1) + buf[4*(i + 6*2)];

  1268.             buf[4*(i + 6*0)] = MULH3(out2[i + 6], win[i + 6], 1);

  1269.             out_ptr += SBLIMIT;

  1270.         }

  1271.         imdct12(out2, ptr + 2);

  1272.         for (i = 0; i < 6; i++) {

  1273.             buf[4*(i + 6*0)] = MULH3(out2[i    ], win[i    ], 1) + buf[4*(i + 6*0)];

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

  1275.             buf[4*(i + 6*2)] = 0;

  1276.         }

  1277.         ptr += 18;

  1278.         buf += (j&3) != 3 ? 1 : (4*18-3);

  1279.     }

  1280.     /* zero bands */

  1281.     for (j = sblimit; j < SBLIMIT; j++) {

  1282.         /* overlap */

  1283.         out_ptr = sb_samples + j;

  1284.         for (i = 0; i < 18; i++) {

  1285.             *out_ptr = buf[4*i];

  1286.             buf[4*i]   = 0;

  1287.             out_ptr += SBLIMIT;

  1288.         }

  1289.         buf += (j&3) != 3 ? 1 : (4*18-3);

  1290.     }

  1291. }

  1292. 

  1293. /* main layer3 decoding function */

  1294. static int mp_decode_layer3(MPADecodeContext *s)

  1295. {

  1296.     int nb_granules, main_data_begin;

  1297.     int gr, ch, blocksplit_flag, i, j, k, n, bits_pos;

  1298.     GranuleDef *g;

  1299.     int16_t exponents[576]; //FIXME try INTFLOAT

  1300. 

  1301.     /* read side info */

  1302.     if (s->lsf) {

  1303.         main_data_begin = get_bits(&s->gb, 8);

  1304.         skip_bits(&s->gb, s->nb_channels);

  1305.         nb_granules = 1;

  1306.     } else {

  1307.         main_data_begin = get_bits(&s->gb, 9);

  1308.         if (s->nb_channels == 2)

  1309.             skip_bits(&s->gb, 3);

  1310.         else

  1311.             skip_bits(&s->gb, 5);

  1312.         nb_granules = 2;

  1313.         for (ch = 0; ch < s->nb_channels; ch++) {

  1314.             s->granules[ch][0].scfsi = 0;/* all scale factors are transmitted */

  1315.             s->granules[ch][1].scfsi = get_bits(&s->gb, 4);

  1316.         }

  1317.     }

  1318. 

  1319.     for (gr = 0; gr < nb_granules; gr++) {

  1320.         for (ch = 0; ch < s->nb_channels; ch++) {

  1321.             av_dlog(s->avctx, "gr=%d ch=%d: side_info\n", gr, ch);

  1322.             g = &s->granules[ch][gr];

  1323.             g->part2_3_length = get_bits(&s->gb, 12);

  1324.             g->big_values     = get_bits(&s->gb,  9);

  1325.             if (g->big_values > 288) {

  1326.                 av_log(s->avctx, AV_LOG_ERROR, "big_values too big\n");

  1327.                 return AVERROR_INVALIDDATA;

  1328.             }

  1329. 

  1330.             g->global_gain = get_bits(&s->gb, 8);

  1331.             /* if MS stereo only is selected, we precompute the

  1332.                1/sqrt(2) renormalization factor */

  1333.             if ((s->mode_ext & (MODE_EXT_MS_STEREO | MODE_EXT_I_STEREO)) ==

  1334.                 MODE_EXT_MS_STEREO)

  1335.                 g->global_gain -= 2;

  1336.             if (s->lsf)

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

  1338.             else

  1339.                 g->scalefac_compress = get_bits(&s->gb, 4);

  1340.             blocksplit_flag = get_bits1(&s->gb);

  1341.             if (blocksplit_flag) {

  1342.                 g->block_type = get_bits(&s->gb, 2);

  1343.                 if (g->block_type == 0) {

  1344.                     av_log(s->avctx, AV_LOG_ERROR, "invalid block type\n");

  1345.                     return AVERROR_INVALIDDATA;

  1346.                 }

  1347.                 g->switch_point = get_bits1(&s->gb);

  1348.                 for (i = 0; i < 2; i++)

  1349.                     g->table_select[i] = get_bits(&s->gb, 5);

  1350.                 for (i = 0; i < 3; i++)

  1351.                     g->subblock_gain[i] = get_bits(&s->gb, 3);

  1352.                 init_short_region(s, g);

  1353.             } else {

  1354.                 int region_address1, region_address2;

  1355.                 g->block_type = 0;

  1356.                 g->switch_point = 0;

  1357.                 for (i = 0; i < 3; i++)

  1358.                     g->table_select[i] = get_bits(&s->gb, 5);

  1359.                 /* compute huffman coded region sizes */

  1360.                 region_address1 = get_bits(&s->gb, 4);

  1361.                 region_address2 = get_bits(&s->gb, 3);

  1362.                 av_dlog(s->avctx, "region1=%d region2=%d\n",

  1363.                         region_address1, region_address2);

  1364.                 init_long_region(s, g, region_address1, region_address2);

  1365.             }

  1366.             region_offset2size(g);

  1367.             compute_band_indexes(s, g);

  1368. 

  1369.             g->preflag = 0;

  1370.             if (!s->lsf)

  1371.                 g->preflag = get_bits1(&s->gb);

  1372.             g->scalefac_scale     = get_bits1(&s->gb);

  1373.             g->count1table_select = get_bits1(&s->gb);

  1374.             av_dlog(s->avctx, "block_type=%d switch_point=%d\n",

  1375.                     g->block_type, g->switch_point);

  1376.         }

  1377.     }

  1378. 

  1379.     if (!s->adu_mode) {

  1380.         int skip;

  1381.         const uint8_t *ptr = s->gb.buffer + (get_bits_count(&s->gb)>>3);

  1382.         int extrasize = av_clip(get_bits_left(&s->gb) >> 3, 0, EXTRABYTES);

  1383.         av_assert1((get_bits_count(&s->gb) & 7) == 0);

  1384.         /* now we get bits from the main_data_begin offset */

  1385.         av_dlog(s->avctx, "seekback:%d, lastbuf:%d\n",

  1386.                 main_data_begin, s->last_buf_size);

  1387. 

  1388.         memcpy(s->last_buf + s->last_buf_size, ptr, extrasize);

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

  1390.         init_get_bits(&s->gb, s->last_buf, s->last_buf_size*8);

  1391. #if !UNCHECKED_BITSTREAM_READER

  1392.         s->gb.size_in_bits_plus8 += FFMAX(extrasize, LAST_BUF_SIZE - s->last_buf_size) * 8;

  1393. #endif

  1394.         s->last_buf_size <<= 3;

  1395.         for (gr = 0; gr < nb_granules && (s->last_buf_size >> 3) < main_data_begin; gr++) {

  1396.             for (ch = 0; ch < s->nb_channels; ch++) {

  1397.                 g = &s->granules[ch][gr];

  1398.                 s->last_buf_size += g->part2_3_length;

  1399.                 memset(g->sb_hybrid, 0, sizeof(g->sb_hybrid));

  1400.                 compute_imdct(s, g, &s->sb_samples[ch][18 * gr][0], s->mdct_buf[ch]);

  1401.             }

  1402.         }

  1403.         skip = s->last_buf_size - 8 * main_data_begin;

  1404.         if (skip >= s->gb.size_in_bits && s->in_gb.buffer) {

  1405.             skip_bits_long(&s->in_gb, skip - s->gb.size_in_bits);

  1406.             s->gb           = s->in_gb;

  1407.             s->in_gb.buffer = NULL;

  1408.         } else {

  1409.             skip_bits_long(&s->gb, skip);

  1410.         }

  1411.     } else {

  1412.         gr = 0;

  1413.     }

  1414. 

  1415.     for (; gr < nb_granules; gr++) {

  1416.         for (ch = 0; ch < s->nb_channels; ch++) {

  1417.             g = &s->granules[ch][gr];

  1418.             bits_pos = get_bits_count(&s->gb);

  1419. 

  1420.             if (!s->lsf) {

  1421.                 uint8_t *sc;

  1422.                 int slen, slen1, slen2;

  1423. 

  1424.                 /* MPEG1 scale factors */

  1425.                 slen1 = slen_table[0][g->scalefac_compress];

  1426.                 slen2 = slen_table[1][g->scalefac_compress];

  1427.                 av_dlog(s->avctx, "slen1=%d slen2=%d\n", slen1, slen2);

  1428.                 if (g->block_type == 2) {

  1429.                     n = g->switch_point ? 17 : 18;

  1430.                     j = 0;

  1431.                     if (slen1) {

  1432.                         for (i = 0; i < n; i++)

  1433.                             g->scale_factors[j++] = get_bits(&s->gb, slen1);

  1434.                     } else {

  1435.                         for (i = 0; i < n; i++)

  1436.                             g->scale_factors[j++] = 0;

  1437.                     }

  1438.                     if (slen2) {

  1439.                         for (i = 0; i < 18; i++)

  1440.                             g->scale_factors[j++] = get_bits(&s->gb, slen2);

  1441.                         for (i = 0; i < 3; i++)

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

  1443.                     } else {

  1444.                         for (i = 0; i < 21; i++)

  1445.                             g->scale_factors[j++] = 0;

  1446.                     }

  1447.                 } else {

  1448.                     sc = s->granules[ch][0].scale_factors;

  1449.                     j = 0;

  1450.                     for (k = 0; k < 4; k++) {

  1451.                         n = k == 0 ? 6 : 5;

  1452.                         if ((g->scfsi & (0x8 >> k)) == 0) {

  1453.                             slen = (k < 2) ? slen1 : slen2;

  1454.                             if (slen) {

  1455.                                 for (i = 0; i < n; i++)

  1456.                                     g->scale_factors[j++] = get_bits(&s->gb, slen);

  1457.                             } else {

  1458.                                 for (i = 0; i < n; i++)

  1459.                                     g->scale_factors[j++] = 0;

  1460.                             }

  1461.                         } else {

  1462.                             /* simply copy from last granule */

  1463.                             for (i = 0; i < n; i++) {

  1464.                                 g->scale_factors[j] = sc[j];

  1465.                                 j++;

  1466.                             }

  1467.                         }

  1468.                     }

  1469.                     g->scale_factors[j++] = 0;

  1470.                 }

  1471.             } else {

  1472.                 int tindex, tindex2, slen[4], sl, sf;

  1473. 

  1474.                 /* LSF scale factors */

  1475.                 if (g->block_type == 2)

  1476.                     tindex = g->switch_point ? 2 : 1;

  1477.                 else

  1478.                     tindex = 0;

  1479. 

  1480.                 sf = g->scalefac_compress;

  1481.                 if ((s->mode_ext & MODE_EXT_I_STEREO) && ch == 1) {

  1482.                     /* intensity stereo case */

  1483.                     sf >>= 1;

  1484.                     if (sf < 180) {

  1485.                         lsf_sf_expand(slen, sf, 6, 6, 0);

  1486.                         tindex2 = 3;

  1487.                     } else if (sf < 244) {

  1488.                         lsf_sf_expand(slen, sf - 180, 4, 4, 0);

  1489.                         tindex2 = 4;

  1490.                     } else {

  1491.                         lsf_sf_expand(slen, sf - 244, 3, 0, 0);

  1492.                         tindex2 = 5;

  1493.                     }

  1494.                 } else {

  1495.                     /* normal case */

  1496.                     if (sf < 400) {

  1497.                         lsf_sf_expand(slen, sf, 5, 4, 4);

  1498.                         tindex2 = 0;

  1499.                     } else if (sf < 500) {

  1500.                         lsf_sf_expand(slen, sf - 400, 5, 4, 0);

  1501.                         tindex2 = 1;

  1502.                     } else {

  1503.                         lsf_sf_expand(slen, sf - 500, 3, 0, 0);

  1504.                         tindex2 = 2;

  1505.                         g->preflag = 1;

  1506.                     }

  1507.                 }

  1508. 

  1509.                 j = 0;

  1510.                 for (k = 0; k < 4; k++) {

  1511.                     n  = lsf_nsf_table[tindex2][tindex][k];

  1512.                     sl = slen[k];

  1513.                     if (sl) {

  1514.                         for (i = 0; i < n; i++)

  1515.                             g->scale_factors[j++] = get_bits(&s->gb, sl);

  1516.                     } else {

  1517.                         for (i = 0; i < n; i++)

  1518.                             g->scale_factors[j++] = 0;

  1519.                     }

  1520.                 }

  1521.                 /* XXX: should compute exact size */

  1522.                 for (; j < 40; j++)

  1523.                     g->scale_factors[j] = 0;

  1524.             }

  1525. 

  1526.             exponents_from_scale_factors(s, g, exponents);

  1527. 

  1528.             /* read Huffman coded residue */

  1529.             huffman_decode(s, g, exponents, bits_pos + g->part2_3_length);

  1530.         } /* ch */

  1531. 

  1532.         if (s->mode == MPA_JSTEREO)

  1533.             compute_stereo(s, &s->granules[0][gr], &s->granules[1][gr]);

  1534. 

  1535.         for (ch = 0; ch < s->nb_channels; ch++) {

  1536.             g = &s->granules[ch][gr];

  1537. 

  1538.             reorder_block(s, g);

  1539.             compute_antialias(s, g);

  1540.             compute_imdct(s, g, &s->sb_samples[ch][18 * gr][0], s->mdct_buf[ch]);

  1541.         }

  1542.     } /* gr */

  1543.     if (get_bits_count(&s->gb) < 0)

  1544.         skip_bits_long(&s->gb, -get_bits_count(&s->gb));

  1545.     return nb_granules * 18;

  1546. }

  1547. 

  1548. static int mp_decode_frame(MPADecodeContext *s, OUT_INT **samples,

  1549.                            const uint8_t *buf, int buf_size)

  1550. {

  1551.     int i, nb_frames, ch, ret;

  1552.     OUT_INT *samples_ptr;

  1553. 

  1554.     init_get_bits(&s->gb, buf + HEADER_SIZE, (buf_size - HEADER_SIZE) * 8);

  1555. 

  1556.     /* skip error protection field */

  1557.     if (s->error_protection)

  1558.         skip_bits(&s->gb, 16);

  1559. 

  1560.     switch(s->layer) {

  1561.     case 1:

  1562.         s->avctx->frame_size = 384;

  1563.         nb_frames = mp_decode_layer1(s);

  1564.         break;

  1565.     case 2:

  1566.         s->avctx->frame_size = 1152;

  1567.         nb_frames = mp_decode_layer2(s);

  1568.         break;

  1569.     case 3:

  1570.         s->avctx->frame_size = s->lsf ? 576 : 1152;

  1571.     default:

  1572.         nb_frames = mp_decode_layer3(s);

  1573. 

  1574.         s->last_buf_size=0;

  1575.         if (s->in_gb.buffer) {

  1576.             align_get_bits(&s->gb);

  1577.             i = get_bits_left(&s->gb)>>3;

  1578.             if (i >= 0 && i <= BACKSTEP_SIZE) {

  1579.                 memmove(s->last_buf, s->gb.buffer + (get_bits_count(&s->gb)>>3), i);

  1580.                 s->last_buf_size=i;

  1581.             } else

  1582.                 av_log(s->avctx, AV_LOG_ERROR, "invalid old backstep %d\n", i);

  1583.             s->gb           = s->in_gb;

  1584.             s->in_gb.buffer = NULL;

  1585.         }

  1586. 

  1587.         align_get_bits(&s->gb);

  1588.         av_assert1((get_bits_count(&s->gb) & 7) == 0);

  1589.         i = get_bits_left(&s->gb) >> 3;

  1590. 

  1591.         if (i < 0 || i > BACKSTEP_SIZE || nb_frames < 0) {

  1592.             if (i < 0)

  1593.                 av_log(s->avctx, AV_LOG_ERROR, "invalid new backstep %d\n", i);

  1594.             i = FFMIN(BACKSTEP_SIZE, buf_size - HEADER_SIZE);

  1595.         }

  1596.         av_assert1(i <= buf_size - HEADER_SIZE && i >= 0);

  1597.         memcpy(s->last_buf + s->last_buf_size, s->gb.buffer + buf_size - HEADER_SIZE - i, i);

  1598.         s->last_buf_size += i;

  1599.     }

  1600. 

  1601.     if(nb_frames < 0)

  1602.         return nb_frames;

  1603. 

  1604.     /* get output buffer */

  1605.     if (!samples) {

  1606.         av_assert0(s->frame != NULL);

  1607.         s->frame->nb_samples = s->avctx->frame_size;

  1608.         if ((ret = ff_get_buffer(s->avctx, s->frame, 0)) < 0)

  1609.             return ret;

  1610.         samples = (OUT_INT **)s->frame->extended_data;

  1611.     }

  1612. 

  1613.     /* apply the synthesis filter */

  1614.     for (ch = 0; ch < s->nb_channels; ch++) {

  1615.         int sample_stride;

  1616.         if (s->avctx->sample_fmt == OUT_FMT_P) {

  1617.             samples_ptr   = samples[ch];

  1618.             sample_stride = 1;

  1619.         } else {

  1620.             samples_ptr   = samples[0] + ch;

  1621.             sample_stride = s->nb_channels;

  1622.         }

  1623.         for (i = 0; i < nb_frames; i++) {

  1624.             RENAME(ff_mpa_synth_filter)(&s->mpadsp, s->synth_buf[ch],

  1625.                                         &(s->synth_buf_offset[ch]),

  1626.                                         RENAME(ff_mpa_synth_window),

  1627.                                         &s->dither_state, samples_ptr,

  1628.                                         sample_stride, s->sb_samples[ch][i]);

  1629.             samples_ptr += 32 * sample_stride;

  1630.         }

  1631.     }

  1632. 

  1633.     return nb_frames * 32 * sizeof(OUT_INT) * s->nb_channels;

  1634. }

  1635. 

  1636. static int decode_frame(AVCodecContext * avctx, void *data, int *got_frame_ptr,

  1637.                         AVPacket *avpkt)

  1638. {

  1639.     const uint8_t *buf  = avpkt->data;

  1640.     int buf_size        = avpkt->size;

  1641.     MPADecodeContext *s = avctx->priv_data;

  1642.     uint32_t header;

  1643.     int ret;

  1644. 

  1645.     while(buf_size && !*buf){

  1646.         buf++;

  1647.         buf_size--;

  1648.     }

  1649. 

  1650.     if (buf_size < HEADER_SIZE)

  1651.         return AVERROR_INVALIDDATA;

  1652. 

  1653.     header = AV_RB32(buf);

  1654.     if (header>>8 == AV_RB32("TAG")>>8) {

  1655.         av_log(avctx, AV_LOG_DEBUG, "discarding ID3 tag\n");

  1656.         return buf_size;

  1657.     }

  1658.     if (ff_mpa_check_header(header) < 0) {

  1659.         av_log(avctx, AV_LOG_ERROR, "Header missing\n");

  1660.         return AVERROR_INVALIDDATA;

  1661.     }

  1662. 

  1663.     if (avpriv_mpegaudio_decode_header((MPADecodeHeader *)s, header) == 1) {

  1664.         /* free format: prepare to compute frame size */

  1665.         s->frame_size = -1;

  1666.         return AVERROR_INVALIDDATA;

  1667.     }

  1668.     /* update codec info */

  1669.     avctx->channels       = s->nb_channels;

  1670.     avctx->channel_layout = s->nb_channels == 1 ? AV_CH_LAYOUT_MONO : AV_CH_LAYOUT_STEREO;

  1671.     if (!avctx->bit_rate)

  1672.         avctx->bit_rate = s->bit_rate;

  1673. 

  1674.     if (s->frame_size <= 0 || s->frame_size > buf_size) {

  1675.         av_log(avctx, AV_LOG_ERROR, "incomplete frame\n");

  1676.         return AVERROR_INVALIDDATA;

  1677.     } else if (s->frame_size < buf_size) {

  1678.         av_log(avctx, AV_LOG_DEBUG, "incorrect frame size - multiple frames in buffer?\n");

  1679.         buf_size= s->frame_size;

  1680.     }

  1681. 

  1682.     s->frame = data;

  1683. 

  1684.     ret = mp_decode_frame(s, NULL, buf, buf_size);

  1685.     if (ret >= 0) {

  1686.         s->frame->nb_samples = avctx->frame_size;

  1687.         *got_frame_ptr       = 1;

  1688.         avctx->sample_rate   = s->sample_rate;

  1689.         //FIXME maybe move the other codec info stuff from above here too

  1690.     } else {

  1691.         av_log(avctx, AV_LOG_ERROR, "Error while decoding MPEG audio frame.\n");

  1692.         /* Only return an error if the bad frame makes up the whole packet or

  1693.          * the error is related to buffer management.

  1694.          * If there is more data in the packet, just consume the bad frame

  1695.          * instead of returning an error, which would discard the whole

  1696.          * packet. */

  1697.         *got_frame_ptr = 0;

  1698.         if (buf_size == avpkt->size || ret != AVERROR_INVALIDDATA)

  1699.             return ret;

  1700.     }

  1701.     s->frame_size = 0;

  1702.     return buf_size;

  1703. }

  1704. 

  1705. static void mp_flush(MPADecodeContext *ctx)

  1706. {

  1707.     memset(ctx->synth_buf, 0, sizeof(ctx->synth_buf));

  1708.     ctx->last_buf_size = 0;

  1709. }

  1710. 

  1711. static void flush(AVCodecContext *avctx)

  1712. {

  1713.     mp_flush(avctx->priv_data);

  1714. }

  1715. 

  1716. #if CONFIG_MP3ADU_DECODER || CONFIG_MP3ADUFLOAT_DECODER

  1717. static int decode_frame_adu(AVCodecContext *avctx, void *data,

  1718.                             int *got_frame_ptr, AVPacket *avpkt)

  1719. {

  1720.     const uint8_t *buf  = avpkt->data;

  1721.     int buf_size        = avpkt->size;

  1722.     MPADecodeContext *s = avctx->priv_data;

  1723.     uint32_t header;

  1724.     int len, ret;

  1725.     int av_unused out_size;

  1726. 

  1727.     len = buf_size;

  1728. 

  1729.     // Discard too short frames

  1730.     if (buf_size < HEADER_SIZE) {

  1731.         av_log(avctx, AV_LOG_ERROR, "Packet is too small\n");

  1732.         return AVERROR_INVALIDDATA;

  1733.     }

  1734. 

  1735. 

  1736.     if (len > MPA_MAX_CODED_FRAME_SIZE)

  1737.         len = MPA_MAX_CODED_FRAME_SIZE;

  1738. 

  1739.     // Get header and restore sync word

  1740.     header = AV_RB32(buf) | 0xffe00000;

  1741. 

  1742.     if (ff_mpa_check_header(header) < 0) { // Bad header, discard frame

  1743.         av_log(avctx, AV_LOG_ERROR, "Invalid frame header\n");

  1744.         return AVERROR_INVALIDDATA;

  1745.     }

  1746. 

  1747.     avpriv_mpegaudio_decode_header((MPADecodeHeader *)s, header);

  1748.     /* update codec info */

  1749.     avctx->sample_rate = s->sample_rate;

  1750.     avctx->channels    = s->nb_channels;

  1751.     avctx->channel_layout = s->nb_channels == 1 ? AV_CH_LAYOUT_MONO : AV_CH_LAYOUT_STEREO;

  1752.     if (!avctx->bit_rate)

  1753.         avctx->bit_rate = s->bit_rate;

  1754. 

  1755.     s->frame_size = len;

  1756. 

  1757.     s->frame = data;

  1758. 

  1759.     ret = mp_decode_frame(s, NULL, buf, buf_size);

  1760.     if (ret < 0) {

  1761.         av_log(avctx, AV_LOG_ERROR, "Error while decoding MPEG audio frame.\n");

  1762.         return ret;

  1763.     }

  1764. 

  1765.     *got_frame_ptr = 1;

  1766. 

  1767.     return buf_size;

  1768. }

  1769. #endif /* CONFIG_MP3ADU_DECODER || CONFIG_MP3ADUFLOAT_DECODER */

  1770. 

  1771. #if CONFIG_MP3ON4_DECODER || CONFIG_MP3ON4FLOAT_DECODER

  1772. 

  1773. /**

  1774.  * Context for MP3On4 decoder

  1775.  */

  1776. typedef struct MP3On4DecodeContext {

  1777.     int frames;                     ///< number of mp3 frames per block (number of mp3 decoder instances)

  1778.     int syncword;                   ///< syncword patch

  1779.     const uint8_t *coff;            ///< channel offsets in output buffer

  1780.     MPADecodeContext *mp3decctx[5]; ///< MPADecodeContext for every decoder instance

  1781. } MP3On4DecodeContext;

  1782. 

  1783. #include "mpeg4audio.h"

  1784. 

  1785. /* Next 3 arrays are indexed by channel config number (passed via codecdata) */

  1786. 

  1787. /* number of mp3 decoder instances */

  1788. static const uint8_t mp3Frames[8] = { 0, 1, 1, 2, 3, 3, 4, 5 };

  1789. 

  1790. /* offsets into output buffer, assume output order is FL FR C LFE BL BR SL SR */

  1791. static const uint8_t chan_offset[8][5] = {

  1792.     { 0             },

  1793.     { 0             },  // C

  1794.     { 0             },  // FLR

  1795.     { 2, 0          },  // C FLR

  1796.     { 2, 0, 3       },  // C FLR BS

  1797.     { 2, 0, 3       },  // C FLR BLRS

  1798.     { 2, 0, 4, 3    },  // C FLR BLRS LFE

  1799.     { 2, 0, 6, 4, 3 },  // C FLR BLRS BLR LFE

  1800. };

  1801. 

  1802. /* mp3on4 channel layouts */

  1803. static const int16_t chan_layout[8] = {

  1804.     0,

  1805.     AV_CH_LAYOUT_MONO,

  1806.     AV_CH_LAYOUT_STEREO,

  1807.     AV_CH_LAYOUT_SURROUND,

  1808.     AV_CH_LAYOUT_4POINT0,

  1809.     AV_CH_LAYOUT_5POINT0,

  1810.     AV_CH_LAYOUT_5POINT1,

  1811.     AV_CH_LAYOUT_7POINT1

  1812. };

  1813. 

  1814. static av_cold int decode_close_mp3on4(AVCodecContext * avctx)

  1815. {

  1816.     MP3On4DecodeContext *s = avctx->priv_data;

  1817.     int i;

  1818. 

  1819.     for (i = 0; i < s->frames; i++)

  1820.         av_free(s->mp3decctx[i]);

  1821. 

  1822.     return 0;

  1823. }

  1824. 

  1825. 

  1826. static av_cold int decode_init_mp3on4(AVCodecContext * avctx)

  1827. {

  1828.     MP3On4DecodeContext *s = avctx->priv_data;

  1829.     MPEG4AudioConfig cfg;

  1830.     int i;

  1831. 

  1832.     if ((avctx->extradata_size < 2) || (avctx->extradata == NULL)) {

  1833.         av_log(avctx, AV_LOG_ERROR, "Codec extradata missing or too short.\n");

  1834.         return AVERROR_INVALIDDATA;

  1835.     }

  1836. 

  1837.     avpriv_mpeg4audio_get_config(&cfg, avctx->extradata,

  1838.                                  avctx->extradata_size * 8, 1);

  1839.     if (!cfg.chan_config || cfg.chan_config > 7) {

  1840.         av_log(avctx, AV_LOG_ERROR, "Invalid channel config number.\n");

  1841.         return AVERROR_INVALIDDATA;

  1842.     }

  1843.     s->frames             = mp3Frames[cfg.chan_config];

  1844.     s->coff               = chan_offset[cfg.chan_config];

  1845.     avctx->channels       = ff_mpeg4audio_channels[cfg.chan_config];

  1846.     avctx->channel_layout = chan_layout[cfg.chan_config];

  1847. 

  1848.     if (cfg.sample_rate < 16000)

  1849.         s->syncword = 0xffe00000;

  1850.     else

  1851.         s->syncword = 0xfff00000;

  1852. 

  1853.     /* Init the first mp3 decoder in standard way, so that all tables get builded

  1854.      * We replace avctx->priv_data with the context of the first decoder so that

  1855.      * decode_init() does not have to be changed.

  1856.      * Other decoders will be initialized here copying data from the first context

  1857.      */

  1858.     // Allocate zeroed memory for the first decoder context

  1859.     s->mp3decctx[0] = av_mallocz(sizeof(MPADecodeContext));

  1860.     if (!s->mp3decctx[0])

  1861.         goto alloc_fail;

  1862.     // Put decoder context in place to make init_decode() happy

  1863.     avctx->priv_data = s->mp3decctx[0];

  1864.     decode_init(avctx);

  1865.     // Restore mp3on4 context pointer

  1866.     avctx->priv_data = s;

  1867.     s->mp3decctx[0]->adu_mode = 1; // Set adu mode

  1868. 

  1869.     /* Create a separate codec/context for each frame (first is already ok).

  1870.      * Each frame is 1 or 2 channels - up to 5 frames allowed

  1871.      */

  1872.     for (i = 1; i < s->frames; i++) {

  1873.         s->mp3decctx[i] = av_mallocz(sizeof(MPADecodeContext));

  1874.         if (!s->mp3decctx[i])

  1875.             goto alloc_fail;

  1876.         s->mp3decctx[i]->adu_mode = 1;

  1877.         s->mp3decctx[i]->avctx = avctx;

  1878.         s->mp3decctx[i]->mpadsp = s->mp3decctx[0]->mpadsp;

  1879.     }

  1880. 

  1881.     return 0;

  1882. alloc_fail:

  1883.     decode_close_mp3on4(avctx);

  1884.     return AVERROR(ENOMEM);

  1885. }

  1886. 

  1887. 

  1888. static void flush_mp3on4(AVCodecContext *avctx)

  1889. {

  1890.     int i;

  1891.     MP3On4DecodeContext *s = avctx->priv_data;

  1892. 

  1893.     for (i = 0; i < s->frames; i++)

  1894.         mp_flush(s->mp3decctx[i]);

  1895. }

  1896. 

  1897. 

  1898. static int decode_frame_mp3on4(AVCodecContext *avctx, void *data,

  1899.                                int *got_frame_ptr, AVPacket *avpkt)

  1900. {

  1901.     AVFrame *frame         = data;

  1902.     const uint8_t *buf     = avpkt->data;

  1903.     int buf_size           = avpkt->size;

  1904.     MP3On4DecodeContext *s = avctx->priv_data;

  1905.     MPADecodeContext *m;

  1906.     int fsize, len = buf_size, out_size = 0;

  1907.     uint32_t header;

  1908.     OUT_INT **out_samples;

  1909.     OUT_INT *outptr[2];

  1910.     int fr, ch, ret;

  1911. 

  1912.     /* get output buffer */

  1913.     frame->nb_samples = MPA_FRAME_SIZE;

  1914.     if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)

  1915.         return ret;

  1916.     out_samples = (OUT_INT **)frame->extended_data;

  1917. 

  1918.     // Discard too short frames

  1919.     if (buf_size < HEADER_SIZE)

  1920.         return AVERROR_INVALIDDATA;

  1921. 

  1922.     avctx->bit_rate = 0;

  1923. 

  1924.     ch = 0;

  1925.     for (fr = 0; fr < s->frames; fr++) {

  1926.         fsize = AV_RB16(buf) >> 4;

  1927.         fsize = FFMIN3(fsize, len, MPA_MAX_CODED_FRAME_SIZE);

  1928.         m     = s->mp3decctx[fr];

  1929.         av_assert1(m);

  1930. 

  1931.         if (fsize < HEADER_SIZE) {

  1932.             av_log(avctx, AV_LOG_ERROR, "Frame size smaller than header size\n");

  1933.             return AVERROR_INVALIDDATA;

  1934.         }

  1935.         header = (AV_RB32(buf) & 0x000fffff) | s->syncword; // patch header

  1936. 

  1937.         if (ff_mpa_check_header(header) < 0) {

  1938.             av_log(avctx, AV_LOG_ERROR, "Bad header, discard block\n");

  1939.             return AVERROR_INVALIDDATA;

  1940.         }

  1941. 

  1942.         avpriv_mpegaudio_decode_header((MPADecodeHeader *)m, header);

  1943. 

  1944.         if (ch + m->nb_channels > avctx->channels ||

  1945.             s->coff[fr] + m->nb_channels > avctx->channels) {

  1946.             av_log(avctx, AV_LOG_ERROR, "frame channel count exceeds codec "

  1947.                                         "channel count\n");

  1948.             return AVERROR_INVALIDDATA;

  1949.         }

  1950.         ch += m->nb_channels;

  1951. 

  1952.         outptr[0] = out_samples[s->coff[fr]];

  1953.         if (m->nb_channels > 1)

  1954.             outptr[1] = out_samples[s->coff[fr] + 1];

  1955. 

  1956.         if ((ret = mp_decode_frame(m, outptr, buf, fsize)) < 0)

  1957.             return ret;

  1958. 

  1959.         out_size += ret;

  1960.         buf      += fsize;

  1961.         len      -= fsize;

  1962. 

  1963.         avctx->bit_rate += m->bit_rate;

  1964.     }

  1965. 

  1966.     /* update codec info */

  1967.     avctx->sample_rate = s->mp3decctx[0]->sample_rate;

  1968. 

  1969.     frame->nb_samples = out_size / (avctx->channels * sizeof(OUT_INT));

  1970.     *got_frame_ptr    = 1;

  1971. 

  1972.     return buf_size;

  1973. }

  1974. #endif /* CONFIG_MP3ON4_DECODER || CONFIG_MP3ON4FLOAT_DECODER */