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FFmpeg/libavcodec/mpegaudiodec.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/audioconvert.h"

  28. #include "avcodec.h"

  29. #include "get_bits.h"

  30. #include "mathops.h"

  31. #include "mpegaudiodsp.h"

  32. 

  33. /*

  34.  * TODO:

  35.  *  - test lsf / mpeg25 extensively.

  36.  */

  37. 

  38. #include "mpegaudio.h"

  39. #include "mpegaudiodecheader.h"

  40. 

  41. #define BACKSTEP_SIZE 512

  42. #define EXTRABYTES 24

  43. 

  44. /* layer 3 "granule" */

  45. typedef struct GranuleDef {

  46.     uint8_t scfsi;

  47.     int part2_3_length;

  48.     int big_values;

  49.     int global_gain;

  50.     int scalefac_compress;

  51.     uint8_t block_type;

  52.     uint8_t switch_point;

  53.     int table_select[3];

  54.     int subblock_gain[3];

  55.     uint8_t scalefac_scale;

  56.     uint8_t count1table_select;

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

  58.     int preflag;

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

  60.     uint8_t scale_factors[40];

  61.     INTFLOAT sb_hybrid[SBLIMIT * 18]; /* 576 samples */

  62. } GranuleDef;

  63. 

  64. typedef struct MPADecodeContext {

  65.     MPA_DECODE_HEADER

  66.     uint8_t last_buf[2*BACKSTEP_SIZE + EXTRABYTES];

  67.     int last_buf_size;

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

  69.     uint32_t free_format_next_header;

  70.     GetBitContext gb;

  71.     GetBitContext in_gb;

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

  73.     int synth_buf_offset[MPA_MAX_CHANNELS];

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

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

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

  77. #ifdef DEBUG

  78.     int frame_count;

  79. #endif

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

  81.     int dither_state;

  82.     int error_recognition;

  83.     AVCodecContext* avctx;

  84.     MPADSPContext mpadsp;

  85. } MPADecodeContext;

  86. 

  87. #if CONFIG_FLOAT

  88. #   define SHR(a,b)       ((a)*(1.0f/(1<<(b))))

  89. #   define FIXR_OLD(a)    ((int)((a) * FRAC_ONE + 0.5))

  90. #   define FIXR(x)        ((float)(x))

  91. #   define FIXHR(x)       ((float)(x))

  92. #   define MULH3(x, y, s) ((s)*(y)*(x))

  93. #   define MULLx(x, y, s) ((y)*(x))

  94. #   define RENAME(a) a ## _float

  95. #   define OUT_FMT AV_SAMPLE_FMT_FLT

  96. #else

  97. #   define SHR(a,b)       ((a)>>(b))

  98. /* WARNING: only correct for posititive numbers */

  99. #   define FIXR_OLD(a)    ((int)((a) * FRAC_ONE + 0.5))

  100. #   define FIXR(a)        ((int)((a) * FRAC_ONE + 0.5))

  101. #   define FIXHR(a)       ((int)((a) * (1LL<<32) + 0.5))

  102. #   define MULH3(x, y, s) MULH((s)*(x), y)

  103. #   define MULLx(x, y, s) MULL(x,y,s)

  104. #   define RENAME(a)      a ## _fixed

  105. #   define OUT_FMT AV_SAMPLE_FMT_S16

  106. #endif

  107. 

  108. /****************/

  109. 

  110. #define HEADER_SIZE 4

  111. 

  112. #include "mpegaudiodata.h"

  113. #include "mpegaudiodectab.h"

  114. 

  115. static void RENAME(compute_antialias)(MPADecodeContext *s, GranuleDef *g);

  116. 

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

  118. static VLC huff_vlc[16];

  119. static VLC_TYPE huff_vlc_tables[

  120.   0+128+128+128+130+128+154+166+

  121.   142+204+190+170+542+460+662+414

  122.   ][2];

  123. static const int huff_vlc_tables_sizes[16] = {

  124.   0, 128, 128, 128, 130, 128, 154, 166,

  125.   142, 204, 190, 170, 542, 460, 662, 414

  126. };

  127. static VLC huff_quad_vlc[2];

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

  129. static const int huff_quad_vlc_tables_sizes[2] = {

  130.   128, 16

  131. };

  132. /* computed from band_size_long */

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

  134. #include "mpegaudio_tablegen.h"

  135. /* intensity stereo coef table */

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

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

  138. static int32_t csa_table[8][4];

  139. static float csa_table_float[8][4];

  140. static INTFLOAT mdct_win[8][36];

  141. 

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

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

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

  145. 

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

  147.     division_tab3, division_tab5, NULL, division_tab9

  148. };

  149. 

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

  151. static uint16_t scale_factor_modshift[64];

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

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

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

  155. 

  156. #define SCALE_GEN(v) \

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

  158. 

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

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

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

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

  163. };

  164. 

  165. /**

  166.  * Convert region offsets to region sizes and truncate

  167.  * size to big_values.

  168.  */

  169. static void ff_region_offset2size(GranuleDef *g){

  170.     int i, k, j=0;

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

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

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

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

  175.         j = k;

  176.     }

  177. }

  178. 

  179. static void ff_init_short_region(MPADecodeContext *s, GranuleDef *g){

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

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

  182.     else {

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

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

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

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

  187.         else

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

  189.     }

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

  191. }

  192. 

  193. static void ff_init_long_region(MPADecodeContext *s, GranuleDef *g, int ra1, int ra2){

  194.     int l;

  195.     g->region_size[0] =

  196.         band_index_long[s->sample_rate_index][ra1 + 1] >> 1;

  197.     /* should not overflow */

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

  199.     g->region_size[1] =

  200.         band_index_long[s->sample_rate_index][l] >> 1;

  201. }

  202. 

  203. static void ff_compute_band_indexes(MPADecodeContext *s, GranuleDef *g){

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

  205.         if (g->switch_point) {

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

  207.                 long blocks.  For 8000Hz, we handle the 48 first

  208.                 exponents as long blocks (XXX: check this!) */

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

  210.                 g->long_end = 8;

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

  212.                 g->long_end = 6;

  213.             else

  214.                 g->long_end = 4; /* 8000 Hz */

  215. 

  216.             g->short_start = 2 + (s->sample_rate_index != 8);

  217.         } else {

  218.             g->long_end = 0;

  219.             g->short_start = 0;

  220.         }

  221.     } else {

  222.         g->short_start = 13;

  223.         g->long_end = 22;

  224.     }

  225. }

  226. 

  227. /* layer 1 unscaling */

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

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

  230. {

  231.     int shift, mod;

  232.     int64_t val;

  233. 

  234.     shift = scale_factor_modshift[scale_factor];

  235.     mod = shift & 3;

  236.     shift >>= 2;

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

  238.     shift += n;

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

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

  241. }

  242. 

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

  244. {

  245.     int shift, mod, val;

  246. 

  247.     shift = scale_factor_modshift[scale_factor];

  248.     mod = shift & 3;

  249.     shift >>= 2;

  250. 

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

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

  253.     if (shift > 0)

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

  255.     return val;

  256. }

  257. 

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

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

  260. {

  261.     unsigned int m;

  262.     int e;

  263. 

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

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

  266.     e -= (exponent >> 2);

  267.     assert(e>=1);

  268.     if (e > 31)

  269.         return 0;

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

  271. 

  272.     return m;

  273. }

  274. 

  275. /* all integer n^(4/3) computation code */

  276. #define DEV_ORDER 13

  277. 

  278. #define POW_FRAC_BITS 24

  279. #define POW_FRAC_ONE    (1 << POW_FRAC_BITS)

  280. #define POW_FIX(a)   ((int)((a) * POW_FRAC_ONE))

  281. #define POW_MULL(a,b) (((int64_t)(a) * (int64_t)(b)) >> POW_FRAC_BITS)

  282. 

  283. static int dev_4_3_coefs[DEV_ORDER];

  284. 

  285. static av_cold void int_pow_init(void)

  286. {

  287.     int i, a;

  288. 

  289.     a = POW_FIX(1.0);

  290.     for(i=0;i<DEV_ORDER;i++) {

  291.         a = POW_MULL(a, POW_FIX(4.0 / 3.0) - i * POW_FIX(1.0)) / (i + 1);

  292.         dev_4_3_coefs[i] = a;

  293.     }

  294. }

  295. 

  296. static av_cold int decode_init(AVCodecContext * avctx)

  297. {

  298.     MPADecodeContext *s = avctx->priv_data;

  299.     static int init=0;

  300.     int i, j, k;

  301. 

  302.     s->avctx = avctx;

  303. 

  304.     ff_mpadsp_init(&s->mpadsp);

  305. 

  306.     avctx->sample_fmt= OUT_FMT;

  307.     s->error_recognition= avctx->error_recognition;

  308. 

  309.     if (!init && !avctx->parse_only) {

  310.         int offset;

  311. 

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

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

  314.             int shift, mod;

  315.             /* 1.0 (i = 3) is normalized to 2 ^ FRAC_BITS */

  316.             shift = (i / 3);

  317.             mod = i % 3;

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

  319.         }

  320. 

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

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

  323.             int n, norm;

  324.             n = i + 2;

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

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

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

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

  329.             av_dlog(avctx, "%d: norm=%x s=%x %x %x\n",

  330.                     i, norm,

  331.                     scale_factor_mult[i][0],

  332.                     scale_factor_mult[i][1],

  333.                     scale_factor_mult[i][2]);

  334.         }

  335. 

  336.         RENAME(ff_mpa_synth_init)(RENAME(ff_mpa_synth_window));

  337. 

  338.         /* huffman decode tables */

  339.         offset = 0;

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

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

  342.             int xsize, x, y;

  343.             uint8_t  tmp_bits [512];

  344.             uint16_t tmp_codes[512];

  345. 

  346.             memset(tmp_bits , 0, sizeof(tmp_bits ));

  347.             memset(tmp_codes, 0, sizeof(tmp_codes));

  348. 

  349.             xsize = h->xsize;

  350. 

  351.             j = 0;

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

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

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

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

  356.                 }

  357.             }

  358. 

  359.             /* XXX: fail test */

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

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

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

  363.                      tmp_bits, 1, 1, tmp_codes, 2, 2,

  364.                      INIT_VLC_USE_NEW_STATIC);

  365.             offset += huff_vlc_tables_sizes[i];

  366.         }

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

  368. 

  369.         offset = 0;

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

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

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

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

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

  375.                      INIT_VLC_USE_NEW_STATIC);

  376.             offset += huff_quad_vlc_tables_sizes[i];

  377.         }

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

  379. 

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

  381.             k = 0;

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

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

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

  385.             }

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

  387.         }

  388. 

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

  390. 

  391.         int_pow_init();

  392.         mpegaudio_tableinit();

  393. 

  394.         for (i = 0; i < 4; i++)

  395.             if (ff_mpa_quant_bits[i] < 0)

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

  397.                     int val1, val2, val3, steps;

  398.                     int val = j;

  399.                     steps  = ff_mpa_quant_steps[i];

  400.                     val1 = val % steps;

  401.                     val /= steps;

  402.                     val2 = val % steps;

  403.                     val3 = val / steps;

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

  405.                 }

  406. 

  407. 

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

  409.             float f;

  410.             INTFLOAT v;

  411.             if (i != 6) {

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

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

  414.             } else {

  415.                 v = FIXR(1.0);

  416.             }

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

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

  419.         }

  420.         /* invalid values */

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

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

  423. 

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

  425.             double f;

  426.             int e, k;

  427. 

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

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

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

  431.                 k = i & 1;

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

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

  434.                 av_dlog(avctx, "is_table_lsf %d %d: %x %x\n",

  435.                         i, j, is_table_lsf[j][0][i], is_table_lsf[j][1][i]);

  436.             }

  437.         }

  438. 

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

  440.             float ci, cs, ca;

  441.             ci = ci_table[i];

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

  443.             ca = cs * ci;

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

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

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

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

  448.             csa_table_float[i][0] = cs;

  449.             csa_table_float[i][1] = ca;

  450.             csa_table_float[i][2] = ca + cs;

  451.             csa_table_float[i][3] = ca - cs;

  452.         }

  453. 

  454.         /* compute mdct windows */

  455.         for(i=0;i<36;i++) {

  456.             for(j=0; j<4; j++){

  457.                 double d;

  458. 

  459.                 if(j==2 && i%3 != 1)

  460.                     continue;

  461. 

  462.                 d= sin(M_PI * (i + 0.5) / 36.0);

  463.                 if(j==1){

  464.                     if     (i>=30) d= 0;

  465.                     else if(i>=24) d= sin(M_PI * (i - 18 + 0.5) / 12.0);

  466.                     else if(i>=18) d= 1;

  467.                 }else if(j==3){

  468.                     if     (i<  6) d= 0;

  469.                     else if(i< 12) d= sin(M_PI * (i -  6 + 0.5) / 12.0);

  470.                     else if(i< 18) d= 1;

  471.                 }

  472.                 //merge last stage of imdct into the window coefficients

  473.                 d*= 0.5 / cos(M_PI*(2*i + 19)/72);

  474. 

  475.                 if(j==2)

  476.                     mdct_win[j][i/3] = FIXHR((d / (1<<5)));

  477.                 else

  478.                     mdct_win[j][i  ] = FIXHR((d / (1<<5)));

  479.             }

  480.         }

  481. 

  482.         /* NOTE: we do frequency inversion adter the MDCT by changing

  483.            the sign of the right window coefs */

  484.         for(j=0;j<4;j++) {

  485.             for(i=0;i<36;i+=2) {

  486.                 mdct_win[j + 4][i] = mdct_win[j][i];

  487.                 mdct_win[j + 4][i + 1] = -mdct_win[j][i + 1];

  488.             }

  489.         }

  490. 

  491.         init = 1;

  492.     }

  493. 

  494.     if (avctx->codec_id == CODEC_ID_MP3ADU)

  495.         s->adu_mode = 1;

  496.     return 0;

  497. }

  498. 

  499. #define C3 FIXHR(0.86602540378443864676/2)

  500. 

  501. /* 0.5 / cos(pi*(2*i+1)/36) */

  502. static const INTFLOAT icos36[9] = {

  503.     FIXR(0.50190991877167369479),

  504.     FIXR(0.51763809020504152469), //0

  505.     FIXR(0.55168895948124587824),

  506.     FIXR(0.61038729438072803416),

  507.     FIXR(0.70710678118654752439), //1

  508.     FIXR(0.87172339781054900991),

  509.     FIXR(1.18310079157624925896),

  510.     FIXR(1.93185165257813657349), //2

  511.     FIXR(5.73685662283492756461),

  512. };

  513. 

  514. /* 0.5 / cos(pi*(2*i+1)/36) */

  515. static const INTFLOAT icos36h[9] = {

  516.     FIXHR(0.50190991877167369479/2),

  517.     FIXHR(0.51763809020504152469/2), //0

  518.     FIXHR(0.55168895948124587824/2),

  519.     FIXHR(0.61038729438072803416/2),

  520.     FIXHR(0.70710678118654752439/2), //1

  521.     FIXHR(0.87172339781054900991/2),

  522.     FIXHR(1.18310079157624925896/4),

  523.     FIXHR(1.93185165257813657349/4), //2

  524. //    FIXHR(5.73685662283492756461),

  525. };

  526. 

  527. /* 12 points IMDCT. We compute it "by hand" by factorizing obvious

  528.    cases. */

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

  530. {

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

  532. 

  533.     in0= in[0*3];

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

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

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

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

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

  539.     in5 += in3;

  540.     in3 += in1;

  541. 

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

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

  544. 

  545.     t1 = in0 - in4;

  546.     t2 = MULH3(in1 - in5, icos36h[4], 2);

  547. 

  548.     out[ 7]=

  549.     out[10]= t1 + t2;

  550.     out[ 1]=

  551.     out[ 4]= t1 - t2;

  552. 

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

  554.     in4 = in0 + in2;

  555.     in5 += 2*in1;

  556.     in1 = MULH3(in5 + in3, icos36h[1], 1);

  557.     out[ 8]=

  558.     out[ 9]= in4 + in1;

  559.     out[ 2]=

  560.     out[ 3]= in4 - in1;

  561. 

  562.     in0 -= in2;

  563.     in5 = MULH3(in5 - in3, icos36h[7], 2);

  564.     out[ 0]=

  565.     out[ 5]= in0 - in5;

  566.     out[ 6]=

  567.     out[11]= in0 + in5;

  568. }

  569. 

  570. /* cos(pi*i/18) */

  571. #define C1 FIXHR(0.98480775301220805936/2)

  572. #define C2 FIXHR(0.93969262078590838405/2)

  573. #define C3 FIXHR(0.86602540378443864676/2)

  574. #define C4 FIXHR(0.76604444311897803520/2)

  575. #define C5 FIXHR(0.64278760968653932632/2)

  576. #define C6 FIXHR(0.5/2)

  577. #define C7 FIXHR(0.34202014332566873304/2)

  578. #define C8 FIXHR(0.17364817766693034885/2)

  579. 

  580. 

  581. /* using Lee like decomposition followed by hand coded 9 points DCT */

  582. static void imdct36(INTFLOAT *out, INTFLOAT *buf, INTFLOAT *in, INTFLOAT *win)

  583. {

  584.     int i, j;

  585.     INTFLOAT t0, t1, t2, t3, s0, s1, s2, s3;

  586.     INTFLOAT tmp[18], *tmp1, *in1;

  587. 

  588.     for(i=17;i>=1;i--)

  589.         in[i] += in[i-1];

  590.     for(i=17;i>=3;i-=2)

  591.         in[i] += in[i-2];

  592. 

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

  594.         tmp1 = tmp + j;

  595.         in1 = in + j;

  596. 

  597.         t2 = in1[2*4] + in1[2*8] - in1[2*2];

  598. 

  599.         t3 = in1[2*0] + SHR(in1[2*6],1);

  600.         t1 = in1[2*0] - in1[2*6];

  601.         tmp1[ 6] = t1 - SHR(t2,1);

  602.         tmp1[16] = t1 + t2;

  603. 

  604.         t0 = MULH3(in1[2*2] + in1[2*4] ,    C2, 2);

  605.         t1 = MULH3(in1[2*4] - in1[2*8] , -2*C8, 1);

  606.         t2 = MULH3(in1[2*2] + in1[2*8] ,   -C4, 2);

  607. 

  608.         tmp1[10] = t3 - t0 - t2;

  609.         tmp1[ 2] = t3 + t0 + t1;

  610.         tmp1[14] = t3 + t2 - t1;

  611. 

  612.         tmp1[ 4] = MULH3(in1[2*5] + in1[2*7] - in1[2*1], -C3, 2);

  613.         t2 = MULH3(in1[2*1] + in1[2*5],    C1, 2);

  614.         t3 = MULH3(in1[2*5] - in1[2*7], -2*C7, 1);

  615.         t0 = MULH3(in1[2*3], C3, 2);

  616. 

  617.         t1 = MULH3(in1[2*1] + in1[2*7],   -C5, 2);

  618. 

  619.         tmp1[ 0] = t2 + t3 + t0;

  620.         tmp1[12] = t2 + t1 - t0;

  621.         tmp1[ 8] = t3 - t1 - t0;

  622.     }

  623. 

  624.     i = 0;

  625.     for(j=0;j<4;j++) {

  626.         t0 = tmp[i];

  627.         t1 = tmp[i + 2];

  628.         s0 = t1 + t0;

  629.         s2 = t1 - t0;

  630. 

  631.         t2 = tmp[i + 1];

  632.         t3 = tmp[i + 3];

  633.         s1 = MULH3(t3 + t2, icos36h[j], 2);

  634.         s3 = MULLx(t3 - t2, icos36[8 - j], FRAC_BITS);

  635. 

  636.         t0 = s0 + s1;

  637.         t1 = s0 - s1;

  638.         out[(9 + j)*SBLIMIT] =  MULH3(t1, win[9 + j], 1) + buf[9 + j];

  639.         out[(8 - j)*SBLIMIT] =  MULH3(t1, win[8 - j], 1) + buf[8 - j];

  640.         buf[9 + j] = MULH3(t0, win[18 + 9 + j], 1);

  641.         buf[8 - j] = MULH3(t0, win[18 + 8 - j], 1);

  642. 

  643.         t0 = s2 + s3;

  644.         t1 = s2 - s3;

  645.         out[(9 + 8 - j)*SBLIMIT] =  MULH3(t1, win[9 + 8 - j], 1) + buf[9 + 8 - j];

  646.         out[(        j)*SBLIMIT] =  MULH3(t1, win[        j], 1) + buf[        j];

  647.         buf[9 + 8 - j] = MULH3(t0, win[18 + 9 + 8 - j], 1);

  648.         buf[      + j] = MULH3(t0, win[18         + j], 1);

  649.         i += 4;

  650.     }

  651. 

  652.     s0 = tmp[16];

  653.     s1 = MULH3(tmp[17], icos36h[4], 2);

  654.     t0 = s0 + s1;

  655.     t1 = s0 - s1;

  656.     out[(9 + 4)*SBLIMIT] =  MULH3(t1, win[9 + 4], 1) + buf[9 + 4];

  657.     out[(8 - 4)*SBLIMIT] =  MULH3(t1, win[8 - 4], 1) + buf[8 - 4];

  658.     buf[9 + 4] = MULH3(t0, win[18 + 9 + 4], 1);

  659.     buf[8 - 4] = MULH3(t0, win[18 + 8 - 4], 1);

  660. }

  661. 

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

  663. static int mp_decode_layer1(MPADecodeContext *s)

  664. {

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

  666.     uint8_t allocation[MPA_MAX_CHANNELS][SBLIMIT];

  667.     uint8_t scale_factors[MPA_MAX_CHANNELS][SBLIMIT];

  668. 

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

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

  671.     else

  672.         bound = SBLIMIT;

  673. 

  674.     /* allocation bits */

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

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

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

  678.         }

  679.     }

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

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

  682.     }

  683. 

  684.     /* scale factors */

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

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

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

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

  689.         }

  690.     }

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

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

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

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

  695.         }

  696.     }

  697. 

  698.     /* compute samples */

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

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

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

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

  703.                 if (n) {

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

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

  706.                 } else {

  707.                     v = 0;

  708.                 }

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

  710.             }

  711.         }

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

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

  714.             if (n) {

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

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

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

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

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

  720.             } else {

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

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

  723.             }

  724.         }

  725.     }

  726.     return 12;

  727. }

  728. 

  729. static int mp_decode_layer2(MPADecodeContext *s)

  730. {

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

  732.     const unsigned char *alloc_table;

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

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

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

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

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

  738. 

  739.     /* select decoding table */

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

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

  742.     sblimit = ff_mpa_sblimit_table[table];

  743.     alloc_table = ff_mpa_alloc_tables[table];

  744. 

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

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

  747.     else

  748.         bound = sblimit;

  749. 

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

  751. 

  752.     /* sanity check */

  753.     if( bound > sblimit ) bound = sblimit;

  754. 

  755.     /* parse bit allocation */

  756.     j = 0;

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

  758.         bit_alloc_bits = alloc_table[j];

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

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

  761.         }

  762.         j += 1 << bit_alloc_bits;

  763.     }

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

  765.         bit_alloc_bits = alloc_table[j];

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

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

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

  769.         j += 1 << bit_alloc_bits;

  770.     }

  771. 

  772.     /* scale codes */

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

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

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

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

  777.         }

  778.     }

  779. 

  780.     /* scale factors */

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

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

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

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

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

  786.                 default:

  787.                 case 0:

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

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

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

  791.                     break;

  792.                 case 2:

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

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

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

  796.                     break;

  797.                 case 1:

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

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

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

  801.                     break;

  802.                 case 3:

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

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

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

  806.                     break;

  807.                 }

  808.             }

  809.         }

  810.     }

  811. 

  812.     /* samples */

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

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

  815.             j = 0;

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

  817.                 bit_alloc_bits = alloc_table[j];

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

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

  820.                     if (b) {

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

  822.                         qindex = alloc_table[j+b];

  823.                         bits = ff_mpa_quant_bits[qindex];

  824.                         if (bits < 0) {

  825.                             int v2;

  826.                             /* 3 values at the same time */

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

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

  829.                             steps  = ff_mpa_quant_steps[qindex];

  830. 

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

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

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

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

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

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

  837.                         } else {

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

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

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

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

  842.                             }

  843.                         }

  844.                     } else {

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

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

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

  848.                     }

  849.                 }

  850.                 /* next subband in alloc table */

  851.                 j += 1 << bit_alloc_bits;

  852.             }

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

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

  855.                 bit_alloc_bits = alloc_table[j];

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

  857.                 if (b) {

  858.                     int mant, scale0, scale1;

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

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

  861.                     qindex = alloc_table[j+b];

  862.                     bits = ff_mpa_quant_bits[qindex];

  863.                     if (bits < 0) {

  864.                         /* 3 values at the same time */

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

  866.                         steps = ff_mpa_quant_steps[qindex];

  867.                         mant = v % steps;

  868.                         v = v / steps;

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

  870.                             l2_unscale_group(steps, mant, scale0);

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

  872.                             l2_unscale_group(steps, mant, scale1);

  873.                         mant = v % steps;

  874.                         v = v / steps;

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

  876.                             l2_unscale_group(steps, mant, scale0);

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

  878.                             l2_unscale_group(steps, mant, scale1);

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

  880.                             l2_unscale_group(steps, v, scale0);

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

  882.                             l2_unscale_group(steps, v, scale1);

  883.                     } else {

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

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

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

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

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

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

  890.                         }

  891.                     }

  892.                 } else {

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

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

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

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

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

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

  899.                 }

  900.                 /* next subband in alloc table */

  901.                 j += 1 << bit_alloc_bits;

  902.             }

  903.             /* fill remaining samples to zero */

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

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

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

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

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

  909.                 }

  910.             }

  911.         }

  912.     }

  913.     return 3 * 12;

  914. }

  915. 

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

  917.     if(n==3){\

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

  919.         dst= sf - 3*m;\

  920.         sf=m;\

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

  922.         dst= sf&3;\

  923.         sf>>=2;\

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

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

  926.         dst= sf - 5*m;\

  927.         sf=m;\

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

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

  930.         dst= sf - 6*m;\

  931.         sf=m;\

  932.     }else{\

  933.         dst=0;\

  934.     }

  935. 

  936. static av_always_inline void lsf_sf_expand(int *slen,

  937.                                  int sf, int n1, int n2, int n3)

  938. {

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

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

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

  942.     slen[0] = sf;

  943. }

  944. 

  945. static void exponents_from_scale_factors(MPADecodeContext *s,

  946.                                          GranuleDef *g,

  947.                                          int16_t *exponents)

  948. {

  949.     const uint8_t *bstab, *pretab;

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

  951.     int16_t *exp_ptr;

  952. 

  953.     exp_ptr = exponents;

  954.     gain = g->global_gain - 210;

  955.     shift = g->scalefac_scale + 1;

  956. 

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

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

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

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

  961.         len = bstab[i];

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

  963.             *exp_ptr++ = v0;

  964.     }

  965. 

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

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

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

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

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

  971.         k = g->long_end;

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

  973.             len = bstab[i];

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

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

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

  977.                 *exp_ptr++ = v0;

  978.             }

  979.         }

  980.     }

  981. }

  982. 

  983. /* handle n = 0 too */

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

  985. {

  986.     if (n == 0)

  987.         return 0;

  988.     else

  989.         return get_bits(s, n);

  990. }

  991. 

  992. 

  993. static void switch_buffer(MPADecodeContext *s, int *pos, int *end_pos, int *end_pos2){

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

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

  996.         s->in_gb.buffer=NULL;

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

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

  999.         *end_pos2=

  1000.         *end_pos= *end_pos2 + get_bits_count(&s->gb) - *pos;

  1001.         *pos= get_bits_count(&s->gb);

  1002.     }

  1003. }

  1004. 

  1005. /* Following is a optimized code for

  1006.             INTFLOAT v = *src

  1007.             if(get_bits1(&s->gb))

  1008.                 v = -v;

  1009.             *dst = v;

  1010. */

  1011. #if CONFIG_FLOAT

  1012. #define READ_FLIP_SIGN(dst,src)\

  1013.             v = AV_RN32A(src) ^ (get_bits1(&s->gb)<<31);\

  1014.             AV_WN32A(dst, v);

  1015. #else

  1016. #define READ_FLIP_SIGN(dst,src)\

  1017.             v= -get_bits1(&s->gb);\

  1018.             *(dst) = (*(src) ^ v) - v;

  1019. #endif

  1020. 

  1021. static int huffman_decode(MPADecodeContext *s, GranuleDef *g,

  1022.                           int16_t *exponents, int end_pos2)

  1023. {

  1024.     int s_index;

  1025.     int i;

  1026.     int last_pos, bits_left;

  1027.     VLC *vlc;

  1028.     int end_pos= FFMIN(end_pos2, s->gb.size_in_bits);

  1029. 

  1030.     /* low frequencies (called big values) */

  1031.     s_index = 0;

  1032.     for(i=0;i<3;i++) {

  1033.         int j, k, l, linbits;

  1034.         j = g->region_size[i];

  1035.         if (j == 0)

  1036.             continue;

  1037.         /* select vlc table */

  1038.         k = g->table_select[i];

  1039.         l = mpa_huff_data[k][0];

  1040.         linbits = mpa_huff_data[k][1];

  1041.         vlc = &huff_vlc[l];

  1042. 

  1043.         if(!l){

  1044.             memset(&g->sb_hybrid[s_index], 0, sizeof(*g->sb_hybrid)*2*j);

  1045.             s_index += 2*j;

  1046.             continue;

  1047.         }

  1048. 

  1049.         /* read huffcode and compute each couple */

  1050.         for(;j>0;j--) {

  1051.             int exponent, x, y;

  1052.             int v;

  1053.             int pos= get_bits_count(&s->gb);

  1054. 

  1055.             if (pos >= end_pos){

  1056. //                av_log(NULL, AV_LOG_ERROR, "pos: %d %d %d %d\n", pos, end_pos, end_pos2, s_index);

  1057.                 switch_buffer(s, &pos, &end_pos, &end_pos2);

  1058. //                av_log(NULL, AV_LOG_ERROR, "new pos: %d %d\n", pos, end_pos);

  1059.                 if(pos >= end_pos)

  1060.                     break;

  1061.             }

  1062.             y = get_vlc2(&s->gb, vlc->table, 7, 3);

  1063. 

  1064.             if(!y){

  1065.                 g->sb_hybrid[s_index  ] =

  1066.                 g->sb_hybrid[s_index+1] = 0;

  1067.                 s_index += 2;

  1068.                 continue;

  1069.             }

  1070. 

  1071.             exponent= exponents[s_index];

  1072. 

  1073.             av_dlog(s->avctx, "region=%d n=%d x=%d y=%d exp=%d\n",

  1074.                     i, g->region_size[i] - j, x, y, exponent);

  1075.             if(y&16){

  1076.                 x = y >> 5;

  1077.                 y = y & 0x0f;

  1078.                 if (x < 15){

  1079.                     READ_FLIP_SIGN(g->sb_hybrid+s_index, RENAME(expval_table)[ exponent ]+x)

  1080.                 }else{

  1081.                     x += get_bitsz(&s->gb, linbits);

  1082.                     v = l3_unscale(x, exponent);

  1083.                     if (get_bits1(&s->gb))

  1084.                         v = -v;

  1085.                     g->sb_hybrid[s_index] = v;

  1086.                 }

  1087.                 if (y < 15){

  1088.                     READ_FLIP_SIGN(g->sb_hybrid+s_index+1, RENAME(expval_table)[ exponent ]+y)

  1089.                 }else{

  1090.                     y += get_bitsz(&s->gb, linbits);

  1091.                     v = l3_unscale(y, exponent);

  1092.                     if (get_bits1(&s->gb))

  1093.                         v = -v;

  1094.                     g->sb_hybrid[s_index+1] = v;

  1095.                 }

  1096.             }else{

  1097.                 x = y >> 5;

  1098.                 y = y & 0x0f;

  1099.                 x += y;

  1100.                 if (x < 15){

  1101.                     READ_FLIP_SIGN(g->sb_hybrid+s_index+!!y, RENAME(expval_table)[ exponent ]+x)

  1102.                 }else{

  1103.                     x += get_bitsz(&s->gb, linbits);

  1104.                     v = l3_unscale(x, exponent);

  1105.                     if (get_bits1(&s->gb))

  1106.                         v = -v;

  1107.                     g->sb_hybrid[s_index+!!y] = v;

  1108.                 }

  1109.                 g->sb_hybrid[s_index+ !y] = 0;

  1110.             }

  1111.             s_index+=2;

  1112.         }

  1113.     }

  1114. 

  1115.     /* high frequencies */

  1116.     vlc = &huff_quad_vlc[g->count1table_select];

  1117.     last_pos=0;

  1118.     while (s_index <= 572) {

  1119.         int pos, code;

  1120.         pos = get_bits_count(&s->gb);

  1121.         if (pos >= end_pos) {

  1122.             if (pos > end_pos2 && last_pos){

  1123.                 /* some encoders generate an incorrect size for this

  1124.                    part. We must go back into the data */

  1125.                 s_index -= 4;

  1126.                 skip_bits_long(&s->gb, last_pos - pos);

  1127.                 av_log(s->avctx, AV_LOG_INFO, "overread, skip %d enddists: %d %d\n", last_pos - pos, end_pos-pos, end_pos2-pos);

  1128.                 if(s->error_recognition >= FF_ER_COMPLIANT)

  1129.                     s_index=0;

  1130.                 break;

  1131.             }

  1132. //                av_log(NULL, AV_LOG_ERROR, "pos2: %d %d %d %d\n", pos, end_pos, end_pos2, s_index);

  1133.             switch_buffer(s, &pos, &end_pos, &end_pos2);

  1134. //                av_log(NULL, AV_LOG_ERROR, "new pos2: %d %d %d\n", pos, end_pos, s_index);

  1135.             if(pos >= end_pos)

  1136.                 break;

  1137.         }

  1138.         last_pos= pos;

  1139. 

  1140.         code = get_vlc2(&s->gb, vlc->table, vlc->bits, 1);

  1141.         av_dlog(s->avctx, "t=%d code=%d\n", g->count1table_select, code);

  1142.         g->sb_hybrid[s_index+0]=

  1143.         g->sb_hybrid[s_index+1]=

  1144.         g->sb_hybrid[s_index+2]=

  1145.         g->sb_hybrid[s_index+3]= 0;

  1146.         while(code){

  1147.             static const int idxtab[16]={3,3,2,2,1,1,1,1,0,0,0,0,0,0,0,0};

  1148.             int v;

  1149.             int pos= s_index+idxtab[code];

  1150.             code ^= 8>>idxtab[code];

  1151.             READ_FLIP_SIGN(g->sb_hybrid+pos, RENAME(exp_table)+exponents[pos])

  1152.         }

  1153.         s_index+=4;

  1154.     }

  1155.     /* skip extension bits */

  1156.     bits_left = end_pos2 - get_bits_count(&s->gb);

  1157. //av_log(NULL, AV_LOG_ERROR, "left:%d buf:%p\n", bits_left, s->in_gb.buffer);

  1158.     if (bits_left < 0 && s->error_recognition >= FF_ER_COMPLIANT) {

  1159.         av_log(s->avctx, AV_LOG_ERROR, "bits_left=%d\n", bits_left);

  1160.         s_index=0;

  1161.     }else if(bits_left > 0 && s->error_recognition >= FF_ER_AGGRESSIVE){

  1162.         av_log(s->avctx, AV_LOG_ERROR, "bits_left=%d\n", bits_left);

  1163.         s_index=0;

  1164.     }

  1165.     memset(&g->sb_hybrid[s_index], 0, sizeof(*g->sb_hybrid)*(576 - s_index));

  1166.     skip_bits_long(&s->gb, bits_left);

  1167. 

  1168.     i= get_bits_count(&s->gb);

  1169.     switch_buffer(s, &i, &end_pos, &end_pos2);

  1170. 

  1171.     return 0;

  1172. }

  1173. 

  1174. /* Reorder short blocks from bitstream order to interleaved order. It

  1175.    would be faster to do it in parsing, but the code would be far more

  1176.    complicated */

  1177. static void reorder_block(MPADecodeContext *s, GranuleDef *g)

  1178. {

  1179.     int i, j, len;

  1180.     INTFLOAT *ptr, *dst, *ptr1;

  1181.     INTFLOAT tmp[576];

  1182. 

  1183.     if (g->block_type != 2)

  1184.         return;

  1185. 

  1186.     if (g->switch_point) {

  1187.         if (s->sample_rate_index != 8) {

  1188.             ptr = g->sb_hybrid + 36;

  1189.         } else {

  1190.             ptr = g->sb_hybrid + 48;

  1191.         }

  1192.     } else {

  1193.         ptr = g->sb_hybrid;

  1194.     }

  1195. 

  1196.     for(i=g->short_start;i<13;i++) {

  1197.         len = band_size_short[s->sample_rate_index][i];

  1198.         ptr1 = ptr;

  1199.         dst = tmp;

  1200.         for(j=len;j>0;j--) {

  1201.             *dst++ = ptr[0*len];

  1202.             *dst++ = ptr[1*len];

  1203.             *dst++ = ptr[2*len];

  1204.             ptr++;

  1205.         }

  1206.         ptr+=2*len;

  1207.         memcpy(ptr1, tmp, len * 3 * sizeof(*ptr1));

  1208.     }

  1209. }

  1210. 

  1211. #define ISQRT2 FIXR(0.70710678118654752440)

  1212. 

  1213. static void compute_stereo(MPADecodeContext *s,

  1214.                            GranuleDef *g0, GranuleDef *g1)

  1215. {

  1216.     int i, j, k, l;

  1217.     int sf_max, sf, len, non_zero_found;

  1218.     INTFLOAT (*is_tab)[16], *tab0, *tab1, tmp0, tmp1, v1, v2;

  1219.     int non_zero_found_short[3];

  1220. 

  1221.     /* intensity stereo */

  1222.     if (s->mode_ext & MODE_EXT_I_STEREO) {

  1223.         if (!s->lsf) {

  1224.             is_tab = is_table;

  1225.             sf_max = 7;

  1226.         } else {

  1227.             is_tab = is_table_lsf[g1->scalefac_compress & 1];

  1228.             sf_max = 16;

  1229.         }

  1230. 

  1231.         tab0 = g0->sb_hybrid + 576;

  1232.         tab1 = g1->sb_hybrid + 576;

  1233. 

  1234.         non_zero_found_short[0] = 0;

  1235.         non_zero_found_short[1] = 0;

  1236.         non_zero_found_short[2] = 0;

  1237.         k = (13 - g1->short_start) * 3 + g1->long_end - 3;

  1238.         for(i = 12;i >= g1->short_start;i--) {

  1239.             /* for last band, use previous scale factor */

  1240.             if (i != 11)

  1241.                 k -= 3;

  1242.             len = band_size_short[s->sample_rate_index][i];

  1243.             for(l=2;l>=0;l--) {

  1244.                 tab0 -= len;

  1245.                 tab1 -= len;

  1246.                 if (!non_zero_found_short[l]) {

  1247.                     /* test if non zero band. if so, stop doing i-stereo */

  1248.                     for(j=0;j<len;j++) {

  1249.                         if (tab1[j] != 0) {

  1250.                             non_zero_found_short[l] = 1;

  1251.                             goto found1;

  1252.                         }

  1253.                     }

  1254.                     sf = g1->scale_factors[k + l];

  1255.                     if (sf >= sf_max)

  1256.                         goto found1;

  1257. 

  1258.                     v1 = is_tab[0][sf];

  1259.                     v2 = is_tab[1][sf];

  1260.                     for(j=0;j<len;j++) {

  1261.                         tmp0 = tab0[j];

  1262.                         tab0[j] = MULLx(tmp0, v1, FRAC_BITS);

  1263.                         tab1[j] = MULLx(tmp0, v2, FRAC_BITS);

  1264.                     }

  1265.                 } else {

  1266.                 found1:

  1267.                     if (s->mode_ext & MODE_EXT_MS_STEREO) {

  1268.                         /* lower part of the spectrum : do ms stereo

  1269.                            if enabled */

  1270.                         for(j=0;j<len;j++) {

  1271.                             tmp0 = tab0[j];

  1272.                             tmp1 = tab1[j];

  1273.                             tab0[j] = MULLx(tmp0 + tmp1, ISQRT2, FRAC_BITS);

  1274.                             tab1[j] = MULLx(tmp0 - tmp1, ISQRT2, FRAC_BITS);

  1275.                         }

  1276.                     }

  1277.                 }

  1278.             }

  1279.         }

  1280. 

  1281.         non_zero_found = non_zero_found_short[0] |

  1282.             non_zero_found_short[1] |

  1283.             non_zero_found_short[2];

  1284. 

  1285.         for(i = g1->long_end - 1;i >= 0;i--) {

  1286.             len = band_size_long[s->sample_rate_index][i];

  1287.             tab0 -= len;

  1288.             tab1 -= len;

  1289.             /* test if non zero band. if so, stop doing i-stereo */

  1290.             if (!non_zero_found) {

  1291.                 for(j=0;j<len;j++) {

  1292.                     if (tab1[j] != 0) {

  1293.                         non_zero_found = 1;

  1294.                         goto found2;

  1295.                     }

  1296.                 }

  1297.                 /* for last band, use previous scale factor */

  1298.                 k = (i == 21) ? 20 : i;

  1299.                 sf = g1->scale_factors[k];

  1300.                 if (sf >= sf_max)

  1301.                     goto found2;

  1302.                 v1 = is_tab[0][sf];

  1303.                 v2 = is_tab[1][sf];

  1304.                 for(j=0;j<len;j++) {

  1305.                     tmp0 = tab0[j];

  1306.                     tab0[j] = MULLx(tmp0, v1, FRAC_BITS);

  1307.                     tab1[j] = MULLx(tmp0, v2, FRAC_BITS);

  1308.                 }

  1309.             } else {

  1310.             found2:

  1311.                 if (s->mode_ext & MODE_EXT_MS_STEREO) {

  1312.                     /* lower part of the spectrum : do ms stereo

  1313.                        if enabled */

  1314.                     for(j=0;j<len;j++) {

  1315.                         tmp0 = tab0[j];

  1316.                         tmp1 = tab1[j];

  1317.                         tab0[j] = MULLx(tmp0 + tmp1, ISQRT2, FRAC_BITS);

  1318.                         tab1[j] = MULLx(tmp0 - tmp1, ISQRT2, FRAC_BITS);

  1319.                     }

  1320.                 }

  1321.             }

  1322.         }

  1323.     } else if (s->mode_ext & MODE_EXT_MS_STEREO) {

  1324.         /* ms stereo ONLY */

  1325.         /* NOTE: the 1/sqrt(2) normalization factor is included in the

  1326.            global gain */

  1327.         tab0 = g0->sb_hybrid;

  1328.         tab1 = g1->sb_hybrid;

  1329.         for(i=0;i<576;i++) {

  1330.             tmp0 = tab0[i];

  1331.             tmp1 = tab1[i];

  1332.             tab0[i] = tmp0 + tmp1;

  1333.             tab1[i] = tmp0 - tmp1;

  1334.         }

  1335.     }

  1336. }

  1337. 

  1338. #if !CONFIG_FLOAT

  1339. static void compute_antialias_fixed(MPADecodeContext *s, GranuleDef *g)

  1340. {

  1341.     int32_t *ptr, *csa;

  1342.     int n, i;

  1343. 

  1344.     /* we antialias only "long" bands */

  1345.     if (g->block_type == 2) {

  1346.         if (!g->switch_point)

  1347.             return;

  1348.         /* XXX: check this for 8000Hz case */

  1349.         n = 1;

  1350.     } else {

  1351.         n = SBLIMIT - 1;

  1352.     }

  1353. 

  1354.     ptr = g->sb_hybrid + 18;

  1355.     for(i = n;i > 0;i--) {

  1356.         int tmp0, tmp1, tmp2;

  1357.         csa = &csa_table[0][0];

  1358. #define INT_AA(j) \

  1359.             tmp0 = ptr[-1-j];\

  1360.             tmp1 = ptr[   j];\

  1361.             tmp2= MULH(tmp0 + tmp1, csa[0+4*j]);\

  1362.             ptr[-1-j] = 4*(tmp2 - MULH(tmp1, csa[2+4*j]));\

  1363.             ptr[   j] = 4*(tmp2 + MULH(tmp0, csa[3+4*j]));

  1364. 

  1365.         INT_AA(0)

  1366.         INT_AA(1)

  1367.         INT_AA(2)

  1368.         INT_AA(3)

  1369.         INT_AA(4)

  1370.         INT_AA(5)

  1371.         INT_AA(6)

  1372.         INT_AA(7)

  1373. 

  1374.         ptr += 18;

  1375.     }

  1376. }

  1377. #endif

  1378. 

  1379. static void compute_imdct(MPADecodeContext *s,

  1380.                           GranuleDef *g,

  1381.                           INTFLOAT *sb_samples,

  1382.                           INTFLOAT *mdct_buf)

  1383. {

  1384.     INTFLOAT *win, *win1, *out_ptr, *ptr, *buf, *ptr1;

  1385.     INTFLOAT out2[12];

  1386.     int i, j, mdct_long_end, sblimit;

  1387. 

  1388.     /* find last non zero block */

  1389.     ptr = g->sb_hybrid + 576;

  1390.     ptr1 = g->sb_hybrid + 2 * 18;

  1391.     while (ptr >= ptr1) {

  1392.         int32_t *p;

  1393.         ptr -= 6;

  1394.         p= (int32_t*)ptr;

  1395.         if(p[0] | p[1] | p[2] | p[3] | p[4] | p[5])

  1396.             break;

  1397.     }

  1398.     sblimit = ((ptr - g->sb_hybrid) / 18) + 1;

  1399. 

  1400.     if (g->block_type == 2) {

  1401.         /* XXX: check for 8000 Hz */

  1402.         if (g->switch_point)

  1403.             mdct_long_end = 2;

  1404.         else

  1405.             mdct_long_end = 0;

  1406.     } else {

  1407.         mdct_long_end = sblimit;

  1408.     }

  1409. 

  1410.     buf = mdct_buf;

  1411.     ptr = g->sb_hybrid;

  1412.     for(j=0;j<mdct_long_end;j++) {

  1413.         /* apply window & overlap with previous buffer */

  1414.         out_ptr = sb_samples + j;

  1415.         /* select window */

  1416.         if (g->switch_point && j < 2)

  1417.             win1 = mdct_win[0];

  1418.         else

  1419.             win1 = mdct_win[g->block_type];

  1420.         /* select frequency inversion */

  1421.         win = win1 + ((4 * 36) & -(j & 1));

  1422.         imdct36(out_ptr, buf, ptr, win);

  1423.         out_ptr += 18*SBLIMIT;

  1424.         ptr += 18;

  1425.         buf += 18;

  1426.     }

  1427.     for(j=mdct_long_end;j<sblimit;j++) {

  1428.         /* select frequency inversion */

  1429.         win = mdct_win[2] + ((4 * 36) & -(j & 1));

  1430.         out_ptr = sb_samples + j;

  1431. 

  1432.         for(i=0; i<6; i++){

  1433.             *out_ptr = buf[i];

  1434.             out_ptr += SBLIMIT;

  1435.         }

  1436.         imdct12(out2, ptr + 0);

  1437.         for(i=0;i<6;i++) {

  1438.             *out_ptr     = MULH3(out2[i    ], win[i    ], 1) + buf[i + 6*1];

  1439.             buf[i + 6*2] = MULH3(out2[i + 6], win[i + 6], 1);

  1440.             out_ptr += SBLIMIT;

  1441.         }

  1442.         imdct12(out2, ptr + 1);

  1443.         for(i=0;i<6;i++) {

  1444.             *out_ptr     = MULH3(out2[i    ], win[i    ], 1) + buf[i + 6*2];

  1445.             buf[i + 6*0] = MULH3(out2[i + 6], win[i + 6], 1);

  1446.             out_ptr += SBLIMIT;

  1447.         }

  1448.         imdct12(out2, ptr + 2);

  1449.         for(i=0;i<6;i++) {

  1450.             buf[i + 6*0] = MULH3(out2[i    ], win[i    ], 1) + buf[i + 6*0];

  1451.             buf[i + 6*1] = MULH3(out2[i + 6], win[i + 6], 1);

  1452.             buf[i + 6*2] = 0;

  1453.         }

  1454.         ptr += 18;

  1455.         buf += 18;

  1456.     }

  1457.     /* zero bands */

  1458.     for(j=sblimit;j<SBLIMIT;j++) {

  1459.         /* overlap */

  1460.         out_ptr = sb_samples + j;

  1461.         for(i=0;i<18;i++) {

  1462.             *out_ptr = buf[i];

  1463.             buf[i] = 0;

  1464.             out_ptr += SBLIMIT;

  1465.         }

  1466.         buf += 18;

  1467.     }

  1468. }

  1469. 

  1470. /* main layer3 decoding function */

  1471. static int mp_decode_layer3(MPADecodeContext *s)

  1472. {

  1473.     int nb_granules, main_data_begin, private_bits;

  1474.     int gr, ch, blocksplit_flag, i, j, k, n, bits_pos;

  1475.     GranuleDef *g;

  1476.     int16_t exponents[576]; //FIXME try INTFLOAT

  1477. 

  1478.     /* read side info */

  1479.     if (s->lsf) {

  1480.         main_data_begin = get_bits(&s->gb, 8);

  1481.         private_bits = get_bits(&s->gb, s->nb_channels);

  1482.         nb_granules = 1;

  1483.     } else {

  1484.         main_data_begin = get_bits(&s->gb, 9);

  1485.         if (s->nb_channels == 2)

  1486.             private_bits = get_bits(&s->gb, 3);

  1487.         else

  1488.             private_bits = get_bits(&s->gb, 5);

  1489.         nb_granules = 2;

  1490.         for(ch=0;ch<s->nb_channels;ch++) {

  1491.             s->granules[ch][0].scfsi = 0;/* all scale factors are transmitted */

  1492.             s->granules[ch][1].scfsi = get_bits(&s->gb, 4);

  1493.         }

  1494.     }

  1495. 

  1496.     for(gr=0;gr<nb_granules;gr++) {

  1497.         for(ch=0;ch<s->nb_channels;ch++) {

  1498.             av_dlog(s->avctx, "gr=%d ch=%d: side_info\n", gr, ch);

  1499.             g = &s->granules[ch][gr];

  1500.             g->part2_3_length = get_bits(&s->gb, 12);

  1501.             g->big_values = get_bits(&s->gb, 9);

  1502.             if(g->big_values > 288){

  1503.                 av_log(s->avctx, AV_LOG_ERROR, "big_values too big\n");

  1504.                 return -1;

  1505.             }

  1506. 

  1507.             g->global_gain = get_bits(&s->gb, 8);

  1508.             /* if MS stereo only is selected, we precompute the

  1509.                1/sqrt(2) renormalization factor */

  1510.             if ((s->mode_ext & (MODE_EXT_MS_STEREO | MODE_EXT_I_STEREO)) ==

  1511.                 MODE_EXT_MS_STEREO)

  1512.                 g->global_gain -= 2;

  1513.             if (s->lsf)

  1514.                 g->scalefac_compress = get_bits(&s->gb, 9);

  1515.             else

  1516.                 g->scalefac_compress = get_bits(&s->gb, 4);

  1517.             blocksplit_flag = get_bits1(&s->gb);

  1518.             if (blocksplit_flag) {

  1519.                 g->block_type = get_bits(&s->gb, 2);

  1520.                 if (g->block_type == 0){

  1521.                     av_log(s->avctx, AV_LOG_ERROR, "invalid block type\n");

  1522.                     return -1;

  1523.                 }

  1524.                 g->switch_point = get_bits1(&s->gb);

  1525.                 for(i=0;i<2;i++)

  1526.                     g->table_select[i] = get_bits(&s->gb, 5);

  1527.                 for(i=0;i<3;i++)

  1528.                     g->subblock_gain[i] = get_bits(&s->gb, 3);

  1529.                 ff_init_short_region(s, g);

  1530.             } else {

  1531.                 int region_address1, region_address2;

  1532.                 g->block_type = 0;

  1533.                 g->switch_point = 0;

  1534.                 for(i=0;i<3;i++)

  1535.                     g->table_select[i] = get_bits(&s->gb, 5);

  1536.                 /* compute huffman coded region sizes */

  1537.                 region_address1 = get_bits(&s->gb, 4);

  1538.                 region_address2 = get_bits(&s->gb, 3);

  1539.                 av_dlog(s->avctx, "region1=%d region2=%d\n",

  1540.                         region_address1, region_address2);

  1541.                 ff_init_long_region(s, g, region_address1, region_address2);

  1542.             }

  1543.             ff_region_offset2size(g);

  1544.             ff_compute_band_indexes(s, g);

  1545. 

  1546.             g->preflag = 0;

  1547.             if (!s->lsf)

  1548.                 g->preflag = get_bits1(&s->gb);

  1549.             g->scalefac_scale = get_bits1(&s->gb);

  1550.             g->count1table_select = get_bits1(&s->gb);

  1551.             av_dlog(s->avctx, "block_type=%d switch_point=%d\n",

  1552.                     g->block_type, g->switch_point);

  1553.         }

  1554.     }

  1555. 

  1556.   if (!s->adu_mode) {

  1557.     const uint8_t *ptr = s->gb.buffer + (get_bits_count(&s->gb)>>3);

  1558.     assert((get_bits_count(&s->gb) & 7) == 0);

  1559.     /* now we get bits from the main_data_begin offset */

  1560.     av_dlog(s->avctx, "seekback: %d\n", main_data_begin);

  1561. //av_log(NULL, AV_LOG_ERROR, "backstep:%d, lastbuf:%d\n", main_data_begin, s->last_buf_size);

  1562. 

  1563.     memcpy(s->last_buf + s->last_buf_size, ptr, EXTRABYTES);

  1564.     s->in_gb= s->gb;

  1565.         init_get_bits(&s->gb, s->last_buf, s->last_buf_size*8);

  1566.         skip_bits_long(&s->gb, 8*(s->last_buf_size - main_data_begin));

  1567.   }

  1568. 

  1569.     for(gr=0;gr<nb_granules;gr++) {

  1570.         for(ch=0;ch<s->nb_channels;ch++) {

  1571.             g = &s->granules[ch][gr];

  1572.             if(get_bits_count(&s->gb)<0){

  1573.                 av_log(s->avctx, AV_LOG_DEBUG, "mdb:%d, lastbuf:%d skipping granule %d\n",

  1574.                                             main_data_begin, s->last_buf_size, gr);

  1575.                 skip_bits_long(&s->gb, g->part2_3_length);

  1576.                 memset(g->sb_hybrid, 0, sizeof(g->sb_hybrid));

  1577.                 if(get_bits_count(&s->gb) >= s->gb.size_in_bits && s->in_gb.buffer){

  1578.                     skip_bits_long(&s->in_gb, get_bits_count(&s->gb) - s->gb.size_in_bits);

  1579.                     s->gb= s->in_gb;

  1580.                     s->in_gb.buffer=NULL;

  1581.                 }

  1582.                 continue;

  1583.             }

  1584. 

  1585.             bits_pos = get_bits_count(&s->gb);

  1586. 

  1587.             if (!s->lsf) {

  1588.                 uint8_t *sc;

  1589.                 int slen, slen1, slen2;

  1590. 

  1591.                 /* MPEG1 scale factors */

  1592.                 slen1 = slen_table[0][g->scalefac_compress];

  1593.                 slen2 = slen_table[1][g->scalefac_compress];

  1594.                 av_dlog(s->avctx, "slen1=%d slen2=%d\n", slen1, slen2);

  1595.                 if (g->block_type == 2) {

  1596.                     n = g->switch_point ? 17 : 18;

  1597.                     j = 0;

  1598.                     if(slen1){

  1599.                         for(i=0;i<n;i++)

  1600.                             g->scale_factors[j++] = get_bits(&s->gb, slen1);

  1601.                     }else{

  1602.                         for(i=0;i<n;i++)

  1603.                             g->scale_factors[j++] = 0;

  1604.                     }

  1605.                     if(slen2){

  1606.                         for(i=0;i<18;i++)

  1607.                             g->scale_factors[j++] = get_bits(&s->gb, slen2);

  1608.                         for(i=0;i<3;i++)

  1609.                             g->scale_factors[j++] = 0;

  1610.                     }else{

  1611.                         for(i=0;i<21;i++)

  1612.                             g->scale_factors[j++] = 0;

  1613.                     }

  1614.                 } else {

  1615.                     sc = s->granules[ch][0].scale_factors;

  1616.                     j = 0;

  1617.                     for(k=0;k<4;k++) {

  1618.                         n = (k == 0 ? 6 : 5);

  1619.                         if ((g->scfsi & (0x8 >> k)) == 0) {

  1620.                             slen = (k < 2) ? slen1 : slen2;

  1621.                             if(slen){

  1622.                                 for(i=0;i<n;i++)

  1623.                                     g->scale_factors[j++] = get_bits(&s->gb, slen);

  1624.                             }else{

  1625.                                 for(i=0;i<n;i++)

  1626.                                     g->scale_factors[j++] = 0;

  1627.                             }

  1628.                         } else {

  1629.                             /* simply copy from last granule */

  1630.                             for(i=0;i<n;i++) {

  1631.                                 g->scale_factors[j] = sc[j];

  1632.                                 j++;

  1633.                             }

  1634.                         }

  1635.                     }

  1636.                     g->scale_factors[j++] = 0;

  1637.                 }

  1638.             } else {

  1639.                 int tindex, tindex2, slen[4], sl, sf;

  1640. 

  1641.                 /* LSF scale factors */

  1642.                 if (g->block_type == 2) {

  1643.                     tindex = g->switch_point ? 2 : 1;

  1644.                 } else {

  1645.                     tindex = 0;

  1646.                 }

  1647.                 sf = g->scalefac_compress;

  1648.                 if ((s->mode_ext & MODE_EXT_I_STEREO) && ch == 1) {

  1649.                     /* intensity stereo case */

  1650.                     sf >>= 1;

  1651.                     if (sf < 180) {

  1652.                         lsf_sf_expand(slen, sf, 6, 6, 0);

  1653.                         tindex2 = 3;

  1654.                     } else if (sf < 244) {

  1655.                         lsf_sf_expand(slen, sf - 180, 4, 4, 0);

  1656.                         tindex2 = 4;

  1657.                     } else {

  1658.                         lsf_sf_expand(slen, sf - 244, 3, 0, 0);

  1659.                         tindex2 = 5;

  1660.                     }

  1661.                 } else {

  1662.                     /* normal case */

  1663.                     if (sf < 400) {

  1664.                         lsf_sf_expand(slen, sf, 5, 4, 4);

  1665.                         tindex2 = 0;

  1666.                     } else if (sf < 500) {

  1667.                         lsf_sf_expand(slen, sf - 400, 5, 4, 0);

  1668.                         tindex2 = 1;

  1669.                     } else {

  1670.                         lsf_sf_expand(slen, sf - 500, 3, 0, 0);

  1671.                         tindex2 = 2;

  1672.                         g->preflag = 1;

  1673.                     }

  1674.                 }

  1675. 

  1676.                 j = 0;

  1677.                 for(k=0;k<4;k++) {

  1678.                     n = lsf_nsf_table[tindex2][tindex][k];

  1679.                     sl = slen[k];

  1680.                     if(sl){

  1681.                         for(i=0;i<n;i++)

  1682.                             g->scale_factors[j++] = get_bits(&s->gb, sl);

  1683.                     }else{

  1684.                         for(i=0;i<n;i++)

  1685.                             g->scale_factors[j++] = 0;

  1686.                     }

  1687.                 }

  1688.                 /* XXX: should compute exact size */

  1689.                 for(;j<40;j++)

  1690.                     g->scale_factors[j] = 0;

  1691.             }

  1692. 

  1693.             exponents_from_scale_factors(s, g, exponents);

  1694. 

  1695.             /* read Huffman coded residue */

  1696.             huffman_decode(s, g, exponents, bits_pos + g->part2_3_length);

  1697.         } /* ch */

  1698. 

  1699.         if (s->nb_channels == 2)

  1700.             compute_stereo(s, &s->granules[0][gr], &s->granules[1][gr]);

  1701. 

  1702.         for(ch=0;ch<s->nb_channels;ch++) {

  1703.             g = &s->granules[ch][gr];

  1704. 

  1705.             reorder_block(s, g);

  1706.             RENAME(compute_antialias)(s, g);

  1707.             compute_imdct(s, g, &s->sb_samples[ch][18 * gr][0], s->mdct_buf[ch]);

  1708.         }

  1709.     } /* gr */

  1710.     if(get_bits_count(&s->gb)<0)

  1711.         skip_bits_long(&s->gb, -get_bits_count(&s->gb));

  1712.     return nb_granules * 18;

  1713. }

  1714. 

  1715. static int mp_decode_frame(MPADecodeContext *s,

  1716.                            OUT_INT *samples, const uint8_t *buf, int buf_size)

  1717. {

  1718.     int i, nb_frames, ch;

  1719.     OUT_INT *samples_ptr;

  1720. 

  1721.     init_get_bits(&s->gb, buf + HEADER_SIZE, (buf_size - HEADER_SIZE)*8);

  1722. 

  1723.     /* skip error protection field */

  1724.     if (s->error_protection)

  1725.         skip_bits(&s->gb, 16);

  1726. 

  1727.     switch(s->layer) {

  1728.     case 1:

  1729.         s->avctx->frame_size = 384;

  1730.         nb_frames = mp_decode_layer1(s);

  1731.         break;

  1732.     case 2:

  1733.         s->avctx->frame_size = 1152;

  1734.         nb_frames = mp_decode_layer2(s);

  1735.         break;

  1736.     case 3:

  1737.         s->avctx->frame_size = s->lsf ? 576 : 1152;

  1738.     default:

  1739.         nb_frames = mp_decode_layer3(s);

  1740. 

  1741.         s->last_buf_size=0;

  1742.         if(s->in_gb.buffer){

  1743.             align_get_bits(&s->gb);

  1744.             i= get_bits_left(&s->gb)>>3;

  1745.             if(i >= 0 && i <= BACKSTEP_SIZE){

  1746.                 memmove(s->last_buf, s->gb.buffer + (get_bits_count(&s->gb)>>3), i);

  1747.                 s->last_buf_size=i;

  1748.             }else

  1749.                 av_log(s->avctx, AV_LOG_ERROR, "invalid old backstep %d\n", i);

  1750.             s->gb= s->in_gb;

  1751.             s->in_gb.buffer= NULL;

  1752.         }

  1753. 

  1754.         align_get_bits(&s->gb);

  1755.         assert((get_bits_count(&s->gb) & 7) == 0);

  1756.         i= get_bits_left(&s->gb)>>3;

  1757. 

  1758.         if(i<0 || i > BACKSTEP_SIZE || nb_frames<0){

  1759.             if(i<0)

  1760.                 av_log(s->avctx, AV_LOG_ERROR, "invalid new backstep %d\n", i);

  1761.             i= FFMIN(BACKSTEP_SIZE, buf_size - HEADER_SIZE);

  1762.         }

  1763.         assert(i <= buf_size - HEADER_SIZE && i>= 0);

  1764.         memcpy(s->last_buf + s->last_buf_size, s->gb.buffer + buf_size - HEADER_SIZE - i, i);

  1765.         s->last_buf_size += i;

  1766. 

  1767.         break;

  1768.     }

  1769. 

  1770.     /* apply the synthesis filter */

  1771.     for(ch=0;ch<s->nb_channels;ch++) {

  1772.         samples_ptr = samples + ch;

  1773.         for(i=0;i<nb_frames;i++) {

  1774.             RENAME(ff_mpa_synth_filter)(

  1775.                          &s->mpadsp,

  1776.                          s->synth_buf[ch], &(s->synth_buf_offset[ch]),

  1777.                          RENAME(ff_mpa_synth_window), &s->dither_state,

  1778.                          samples_ptr, s->nb_channels,

  1779.                          s->sb_samples[ch][i]);

  1780.             samples_ptr += 32 * s->nb_channels;

  1781.         }

  1782.     }

  1783. 

  1784.     return nb_frames * 32 * sizeof(OUT_INT) * s->nb_channels;

  1785. }

  1786. 

  1787. static int decode_frame(AVCodecContext * avctx,

  1788.                         void *data, int *data_size,

  1789.                         AVPacket *avpkt)

  1790. {

  1791.     const uint8_t *buf = avpkt->data;

  1792.     int buf_size = avpkt->size;

  1793.     MPADecodeContext *s = avctx->priv_data;

  1794.     uint32_t header;

  1795.     int out_size;

  1796.     OUT_INT *out_samples = data;

  1797. 

  1798.     if(buf_size < HEADER_SIZE)

  1799.         return -1;

  1800. 

  1801.     header = AV_RB32(buf);

  1802.     if(ff_mpa_check_header(header) < 0){

  1803.         av_log(avctx, AV_LOG_ERROR, "Header missing\n");

  1804.         return -1;

  1805.     }

  1806. 

  1807.     if (ff_mpegaudio_decode_header((MPADecodeHeader *)s, header) == 1) {

  1808.         /* free format: prepare to compute frame size */

  1809.         s->frame_size = -1;

  1810.         return -1;

  1811.     }

  1812.     /* update codec info */

  1813.     avctx->channels = s->nb_channels;

  1814.     avctx->channel_layout = s->nb_channels == 1 ? AV_CH_LAYOUT_MONO : AV_CH_LAYOUT_STEREO;

  1815.     if (!avctx->bit_rate)

  1816.         avctx->bit_rate = s->bit_rate;

  1817.     avctx->sub_id = s->layer;

  1818. 

  1819.     if(*data_size < 1152*avctx->channels*sizeof(OUT_INT))

  1820.         return -1;

  1821.     *data_size = 0;

  1822. 

  1823.     if(s->frame_size<=0 || s->frame_size > buf_size){

  1824.         av_log(avctx, AV_LOG_ERROR, "incomplete frame\n");

  1825.         return -1;

  1826.     }else if(s->frame_size < buf_size){

  1827.         av_log(avctx, AV_LOG_ERROR, "incorrect frame size\n");

  1828.         buf_size= s->frame_size;

  1829.     }

  1830. 

  1831.     out_size = mp_decode_frame(s, out_samples, buf, buf_size);

  1832.     if(out_size>=0){

  1833.         *data_size = out_size;

  1834.         avctx->sample_rate = s->sample_rate;

  1835.         //FIXME maybe move the other codec info stuff from above here too

  1836.     }else

  1837.         av_log(avctx, AV_LOG_DEBUG, "Error while decoding MPEG audio frame.\n"); //FIXME return -1 / but also return the number of bytes consumed

  1838.     s->frame_size = 0;

  1839.     return buf_size;

  1840. }

  1841. 

  1842. static void flush(AVCodecContext *avctx){

  1843.     MPADecodeContext *s = avctx->priv_data;

  1844.     memset(s->synth_buf, 0, sizeof(s->synth_buf));

  1845.     s->last_buf_size= 0;

  1846. }

  1847. 

  1848. #if CONFIG_MP3ADU_DECODER || CONFIG_MP3ADUFLOAT_DECODER

  1849. static int decode_frame_adu(AVCodecContext * avctx,

  1850.                         void *data, int *data_size,

  1851.                         AVPacket *avpkt)

  1852. {

  1853.     const uint8_t *buf = avpkt->data;

  1854.     int buf_size = avpkt->size;

  1855.     MPADecodeContext *s = avctx->priv_data;

  1856.     uint32_t header;

  1857.     int len, out_size;

  1858.     OUT_INT *out_samples = data;

  1859. 

  1860.     len = buf_size;

  1861. 

  1862.     // Discard too short frames

  1863.     if (buf_size < HEADER_SIZE) {

  1864.         *data_size = 0;

  1865.         return buf_size;

  1866.     }

  1867. 

  1868. 

  1869.     if (len > MPA_MAX_CODED_FRAME_SIZE)

  1870.         len = MPA_MAX_CODED_FRAME_SIZE;

  1871. 

  1872.     // Get header and restore sync word

  1873.     header = AV_RB32(buf) | 0xffe00000;

  1874. 

  1875.     if (ff_mpa_check_header(header) < 0) { // Bad header, discard frame

  1876.         *data_size = 0;

  1877.         return buf_size;

  1878.     }

  1879. 

  1880.     ff_mpegaudio_decode_header((MPADecodeHeader *)s, header);

  1881.     /* update codec info */

  1882.     avctx->sample_rate = s->sample_rate;

  1883.     avctx->channels = s->nb_channels;

  1884.     if (!avctx->bit_rate)

  1885.         avctx->bit_rate = s->bit_rate;

  1886.     avctx->sub_id = s->layer;

  1887. 

  1888.     s->frame_size = len;

  1889. 

  1890.     if (avctx->parse_only) {

  1891.         out_size = buf_size;

  1892.     } else {

  1893.         out_size = mp_decode_frame(s, out_samples, buf, buf_size);

  1894.     }

  1895. 

  1896.     *data_size = out_size;

  1897.     return buf_size;

  1898. }

  1899. #endif /* CONFIG_MP3ADU_DECODER || CONFIG_MP3ADUFLOAT_DECODER */

  1900. 

  1901. #if CONFIG_MP3ON4_DECODER || CONFIG_MP3ON4FLOAT_DECODER

  1902. 

  1903. /**

  1904.  * Context for MP3On4 decoder

  1905.  */

  1906. typedef struct MP3On4DecodeContext {

  1907.     int frames;   ///< number of mp3 frames per block (number of mp3 decoder instances)

  1908.     int syncword; ///< syncword patch

  1909.     const uint8_t *coff; ///< channels offsets in output buffer

  1910.     MPADecodeContext *mp3decctx[5]; ///< MPADecodeContext for every decoder instance

  1911. } MP3On4DecodeContext;

  1912. 

  1913. #include "mpeg4audio.h"

  1914. 

  1915. /* Next 3 arrays are indexed by channel config number (passed via codecdata) */

  1916. static const uint8_t mp3Frames[8] = {0,1,1,2,3,3,4,5};   /* number of mp3 decoder instances */

  1917. /* offsets into output buffer, assume output order is FL FR BL BR C LFE */

  1918. static const uint8_t chan_offset[8][5] = {

  1919.     {0},

  1920.     {0},            // C

  1921.     {0},            // FLR

  1922.     {2,0},          // C FLR

  1923.     {2,0,3},        // C FLR BS

  1924.     {4,0,2},        // C FLR BLRS

  1925.     {4,0,2,5},      // C FLR BLRS LFE

  1926.     {4,0,2,6,5},    // C FLR BLRS BLR LFE

  1927. };

  1928. 

  1929. 

  1930. static int decode_init_mp3on4(AVCodecContext * avctx)

  1931. {

  1932.     MP3On4DecodeContext *s = avctx->priv_data;

  1933.     MPEG4AudioConfig cfg;

  1934.     int i;

  1935. 

  1936.     if ((avctx->extradata_size < 2) || (avctx->extradata == NULL)) {

  1937.         av_log(avctx, AV_LOG_ERROR, "Codec extradata missing or too short.\n");

  1938.         return -1;

  1939.     }

  1940. 

  1941.     ff_mpeg4audio_get_config(&cfg, avctx->extradata, avctx->extradata_size);

  1942.     if (!cfg.chan_config || cfg.chan_config > 7) {

  1943.         av_log(avctx, AV_LOG_ERROR, "Invalid channel config number.\n");

  1944.         return -1;

  1945.     }

  1946.     s->frames = mp3Frames[cfg.chan_config];

  1947.     s->coff = chan_offset[cfg.chan_config];

  1948.     avctx->channels = ff_mpeg4audio_channels[cfg.chan_config];

  1949. 

  1950.     if (cfg.sample_rate < 16000)

  1951.         s->syncword = 0xffe00000;

  1952.     else

  1953.         s->syncword = 0xfff00000;

  1954. 

  1955.     /* Init the first mp3 decoder in standard way, so that all tables get builded

  1956.      * We replace avctx->priv_data with the context of the first decoder so that

  1957.      * decode_init() does not have to be changed.

  1958.      * Other decoders will be initialized here copying data from the first context

  1959.      */

  1960.     // Allocate zeroed memory for the first decoder context

  1961.     s->mp3decctx[0] = av_mallocz(sizeof(MPADecodeContext));

  1962.     // Put decoder context in place to make init_decode() happy

  1963.     avctx->priv_data = s->mp3decctx[0];

  1964.     decode_init(avctx);

  1965.     // Restore mp3on4 context pointer

  1966.     avctx->priv_data = s;

  1967.     s->mp3decctx[0]->adu_mode = 1; // Set adu mode

  1968. 

  1969.     /* Create a separate codec/context for each frame (first is already ok).

  1970.      * Each frame is 1 or 2 channels - up to 5 frames allowed

  1971.      */

  1972.     for (i = 1; i < s->frames; i++) {

  1973.         s->mp3decctx[i] = av_mallocz(sizeof(MPADecodeContext));

  1974.         s->mp3decctx[i]->adu_mode = 1;

  1975.         s->mp3decctx[i]->avctx = avctx;

  1976.     }

  1977. 

  1978.     return 0;

  1979. }

  1980. 

  1981. 

  1982. static av_cold int decode_close_mp3on4(AVCodecContext * avctx)

  1983. {

  1984.     MP3On4DecodeContext *s = avctx->priv_data;

  1985.     int i;

  1986. 

  1987.     for (i = 0; i < s->frames; i++)

  1988.         av_free(s->mp3decctx[i]);

  1989. 

  1990.     return 0;

  1991. }

  1992. 

  1993. 

  1994. static int decode_frame_mp3on4(AVCodecContext * avctx,

  1995.                         void *data, int *data_size,

  1996.                         AVPacket *avpkt)

  1997. {

  1998.     const uint8_t *buf = avpkt->data;

  1999.     int buf_size = avpkt->size;

  2000.     MP3On4DecodeContext *s = avctx->priv_data;

  2001.     MPADecodeContext *m;

  2002.     int fsize, len = buf_size, out_size = 0;

  2003.     uint32_t header;

  2004.     OUT_INT *out_samples = data;

  2005.     OUT_INT decoded_buf[MPA_FRAME_SIZE * MPA_MAX_CHANNELS];

  2006.     OUT_INT *outptr, *bp;

  2007.     int fr, j, n;

  2008. 

  2009.     if(*data_size < MPA_FRAME_SIZE * MPA_MAX_CHANNELS * s->frames * sizeof(OUT_INT))

  2010.         return -1;

  2011. 

  2012.     *data_size = 0;

  2013.     // Discard too short frames

  2014.     if (buf_size < HEADER_SIZE)

  2015.         return -1;

  2016. 

  2017.     // If only one decoder interleave is not needed

  2018.     outptr = s->frames == 1 ? out_samples : decoded_buf;

  2019. 

  2020.     avctx->bit_rate = 0;

  2021. 

  2022.     for (fr = 0; fr < s->frames; fr++) {

  2023.         fsize = AV_RB16(buf) >> 4;

  2024.         fsize = FFMIN3(fsize, len, MPA_MAX_CODED_FRAME_SIZE);

  2025.         m = s->mp3decctx[fr];

  2026.         assert (m != NULL);

  2027. 

  2028.         header = (AV_RB32(buf) & 0x000fffff) | s->syncword; // patch header

  2029. 

  2030.         if (ff_mpa_check_header(header) < 0) // Bad header, discard block

  2031.             break;

  2032. 

  2033.         ff_mpegaudio_decode_header((MPADecodeHeader *)m, header);

  2034.         out_size += mp_decode_frame(m, outptr, buf, fsize);

  2035.         buf += fsize;

  2036.         len -= fsize;

  2037. 

  2038.         if(s->frames > 1) {

  2039.             n = m->avctx->frame_size*m->nb_channels;

  2040.             /* interleave output data */

  2041.             bp = out_samples + s->coff[fr];

  2042.             if(m->nb_channels == 1) {

  2043.                 for(j = 0; j < n; j++) {

  2044.                     *bp = decoded_buf[j];

  2045.                     bp += avctx->channels;

  2046.                 }

  2047.             } else {

  2048.                 for(j = 0; j < n; j++) {

  2049.                     bp[0] = decoded_buf[j++];

  2050.                     bp[1] = decoded_buf[j];

  2051.                     bp += avctx->channels;

  2052.                 }

  2053.             }

  2054.         }

  2055.         avctx->bit_rate += m->bit_rate;

  2056.     }

  2057. 

  2058.     /* update codec info */

  2059.     avctx->sample_rate = s->mp3decctx[0]->sample_rate;

  2060. 

  2061.     *data_size = out_size;

  2062.     return buf_size;

  2063. }

  2064. #endif /* CONFIG_MP3ON4_DECODER || CONFIG_MP3ON4FLOAT_DECODER */

  2065. 

  2066. #if !CONFIG_FLOAT

  2067. #if CONFIG_MP1_DECODER

  2068. AVCodec ff_mp1_decoder =

  2069. {

  2070.     "mp1",

  2071.     AVMEDIA_TYPE_AUDIO,

  2072.     CODEC_ID_MP1,

  2073.     sizeof(MPADecodeContext),

  2074.     decode_init,

  2075.     NULL,

  2076.     NULL,

  2077.     decode_frame,

  2078.     CODEC_CAP_PARSE_ONLY,

  2079.     .flush= flush,

  2080.     .long_name= NULL_IF_CONFIG_SMALL("MP1 (MPEG audio layer 1)"),

  2081. };

  2082. #endif

  2083. #if CONFIG_MP2_DECODER

  2084. AVCodec ff_mp2_decoder =

  2085. {

  2086.     "mp2",

  2087.     AVMEDIA_TYPE_AUDIO,

  2088.     CODEC_ID_MP2,

  2089.     sizeof(MPADecodeContext),

  2090.     decode_init,

  2091.     NULL,

  2092.     NULL,

  2093.     decode_frame,

  2094.     CODEC_CAP_PARSE_ONLY,

  2095.     .flush= flush,

  2096.     .long_name= NULL_IF_CONFIG_SMALL("MP2 (MPEG audio layer 2)"),

  2097. };

  2098. #endif

  2099. #if CONFIG_MP3_DECODER

  2100. AVCodec ff_mp3_decoder =

  2101. {

  2102.     "mp3",

  2103.     AVMEDIA_TYPE_AUDIO,

  2104.     CODEC_ID_MP3,

  2105.     sizeof(MPADecodeContext),

  2106.     decode_init,

  2107.     NULL,

  2108.     NULL,

  2109.     decode_frame,

  2110.     CODEC_CAP_PARSE_ONLY,

  2111.     .flush= flush,

  2112.     .long_name= NULL_IF_CONFIG_SMALL("MP3 (MPEG audio layer 3)"),

  2113. };

  2114. #endif

  2115. #if CONFIG_MP3ADU_DECODER

  2116. AVCodec ff_mp3adu_decoder =

  2117. {

  2118.     "mp3adu",

  2119.     AVMEDIA_TYPE_AUDIO,

  2120.     CODEC_ID_MP3ADU,

  2121.     sizeof(MPADecodeContext),

  2122.     decode_init,

  2123.     NULL,

  2124.     NULL,

  2125.     decode_frame_adu,

  2126.     CODEC_CAP_PARSE_ONLY,

  2127.     .flush= flush,

  2128.     .long_name= NULL_IF_CONFIG_SMALL("ADU (Application Data Unit) MP3 (MPEG audio layer 3)"),

  2129. };

  2130. #endif

  2131. #if CONFIG_MP3ON4_DECODER

  2132. AVCodec ff_mp3on4_decoder =

  2133. {

  2134.     "mp3on4",

  2135.     AVMEDIA_TYPE_AUDIO,

  2136.     CODEC_ID_MP3ON4,

  2137.     sizeof(MP3On4DecodeContext),

  2138.     decode_init_mp3on4,

  2139.     NULL,

  2140.     decode_close_mp3on4,

  2141.     decode_frame_mp3on4,

  2142.     .flush= flush,

  2143.     .long_name= NULL_IF_CONFIG_SMALL("MP3onMP4"),

  2144. };

  2145. #endif

  2146. #endif