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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 Libav.

  6.  *

  7.  * Libav is free software; you can redistribute it and/or

  8.  * modify it under the terms of the GNU Lesser General Public

  9.  * License as published by the Free Software Foundation; either

  10.  * version 2.1 of the License, or (at your option) any later version.

  11.  *

  12.  * Libav is distributed in the hope that it will be useful,

  13.  * but WITHOUT ANY WARRANTY; without even the implied warranty of

  14.  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

  15.  * Lesser General Public License for more details.

  16.  *

  17.  * You should have received a copy of the GNU Lesser General Public

  18.  * License along with Libav; if not, write to the Free Software

  19.  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

  20.  */

  21. 

  22. /**

  23.  * @file

  24.  * MPEG Audio decoder.

  25.  */

  26. 

  27. #include "libavutil/audioconvert.h"

  28. #include "avcodec.h"

  29. #include "get_bits.h"

  30. #include "dsputil.h"

  31. #include "mathops.h"

  32. #include "mpegaudiodsp.h"

  33. 

  34. /*

  35.  * TODO:

  36.  *  - test lsf / mpeg25 extensively.

  37.  */

  38. 

  39. #include "mpegaudio.h"

  40. #include "mpegaudiodecheader.h"

  41. 

  42. #define BACKSTEP_SIZE 512

  43. #define EXTRABYTES 24

  44. 

  45. /* layer 3 "granule" */

  46. typedef struct GranuleDef {

  47.     uint8_t scfsi;

  48.     int part2_3_length;

  49.     int big_values;

  50.     int global_gain;

  51.     int scalefac_compress;

  52.     uint8_t block_type;

  53.     uint8_t switch_point;

  54.     int table_select[3];

  55.     int subblock_gain[3];

  56.     uint8_t scalefac_scale;

  57.     uint8_t count1table_select;

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

  59.     int preflag;

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

  61.     uint8_t scale_factors[40];

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

  63. } GranuleDef;

  64. 

  65. typedef struct MPADecodeContext {

  66.     MPA_DECODE_HEADER

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

  68.     int last_buf_size;

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

  70.     uint32_t free_format_next_header;

  71.     GetBitContext gb;

  72.     GetBitContext in_gb;

  73.     DECLARE_ALIGNED(16, MPA_INT, synth_buf)[MPA_MAX_CHANNELS][512 * 2];

  74.     int synth_buf_offset[MPA_MAX_CHANNELS];

  75.     DECLARE_ALIGNED(16, INTFLOAT, sb_samples)[MPA_MAX_CHANNELS][36][SBLIMIT];

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

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

  78. #ifdef DEBUG

  79.     int frame_count;

  80. #endif

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

  82.     int dither_state;

  83.     int error_recognition;

  84.     AVCodecContext* avctx;

  85.     MPADSPContext mpadsp;

  86. } MPADecodeContext;

  87. 

  88. #if CONFIG_FLOAT

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

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

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

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

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

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

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

  96. #   define OUT_FMT AV_SAMPLE_FMT_FLT

  97. #else

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

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

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

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

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

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

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

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

  106. #   define OUT_FMT AV_SAMPLE_FMT_S16

  107. #endif

  108. 

  109. /****************/

  110. 

  111. #define HEADER_SIZE 4

  112. 

  113. #include "mpegaudiodata.h"

  114. #include "mpegaudiodectab.h"

  115. 

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

  117. 

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

  119. static VLC huff_vlc[16];

  120. static VLC_TYPE huff_vlc_tables[

  121.   0+128+128+128+130+128+154+166+

  122.   142+204+190+170+542+460+662+414

  123.   ][2];

  124. static const int huff_vlc_tables_sizes[16] = {

  125.   0, 128, 128, 128, 130, 128, 154, 166,

  126.   142, 204, 190, 170, 542, 460, 662, 414

  127. };

  128. static VLC huff_quad_vlc[2];

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

  130. static const int huff_quad_vlc_tables_sizes[2] = {

  131.   128, 16

  132. };

  133. /* computed from band_size_long */

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

  135. #include "mpegaudio_tablegen.h"

  136. /* intensity stereo coef table */

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

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

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

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

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

  142. 

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

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

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

  146. 

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

  148.     division_tab3, division_tab5, NULL, division_tab9

  149. };

  150. 

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

  152. static uint16_t scale_factor_modshift[64];

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

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

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

  156. 

  157. #define SCALE_GEN(v) \

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

  159. 

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

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

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

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

  164. };

  165. 

  166. /**

  167.  * Convert region offsets to region sizes and truncate

  168.  * size to big_values.

  169.  */

  170. static void ff_region_offset2size(GranuleDef *g){

  171.     int i, k, j=0;

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

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

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

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

  176.         j = k;

  177.     }

  178. }

  179. 

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

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

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

  183.     else {

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

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

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

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

  188.         else

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

  190.     }

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

  192. }

  193. 

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

  195.     int l;

  196.     g->region_size[0] =

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

  198.     /* should not overflow */

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

  200.     g->region_size[1] =

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

  202. }

  203. 

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

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

  206.         if (g->switch_point) {

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

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

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

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

  211.                 g->long_end = 8;

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

  213.                 g->long_end = 6;

  214.             else

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

  216. 

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

  218.         } else {

  219.             g->long_end = 0;

  220.             g->short_start = 0;

  221.         }

  222.     } else {

  223.         g->short_start = 13;

  224.         g->long_end = 22;

  225.     }

  226. }

  227. 

  228. /* layer 1 unscaling */

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

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

  231. {

  232.     int shift, mod;

  233.     int64_t val;

  234. 

  235.     shift = scale_factor_modshift[scale_factor];

  236.     mod = shift & 3;

  237.     shift >>= 2;

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

  239.     shift += n;

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

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

  242. }

  243. 

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

  245. {

  246.     int shift, mod, val;

  247. 

  248.     shift = scale_factor_modshift[scale_factor];

  249.     mod = shift & 3;

  250.     shift >>= 2;

  251. 

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

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

  254.     if (shift > 0)

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

  256.     return val;

  257. }

  258. 

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

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

  261. {

  262.     unsigned int m;

  263.     int e;

  264. 

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

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

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

  268.     assert(e>=1);

  269.     if (e > 31)

  270.         return 0;

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

  272. 

  273.     return m;

  274. }

  275. 

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

  277. #define DEV_ORDER 13

  278. 

  279. #define POW_FRAC_BITS 24

  280. #define POW_FRAC_ONE    (1 << POW_FRAC_BITS)

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

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

  283. 

  284. static int dev_4_3_coefs[DEV_ORDER];

  285. 

  286. static av_cold void int_pow_init(void)

  287. {

  288.     int i, a;

  289. 

  290.     a = POW_FIX(1.0);

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

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

  293.         dev_4_3_coefs[i] = a;

  294.     }

  295. }

  296. 

  297. static av_cold int decode_init(AVCodecContext * avctx)

  298. {

  299.     MPADecodeContext *s = avctx->priv_data;

  300.     static int init=0;

  301.     int i, j, k;

  302. 

  303.     s->avctx = avctx;

  304. 

  305.     ff_mpadsp_init(&s->mpadsp);

  306. 

  307.     avctx->sample_fmt= OUT_FMT;

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

  309. 

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

  311.         int offset;

  312. 

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

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

  315.             int shift, mod;

  316.             /* 1.0 (i = 3) is normalized to 2 ^ FRAC_BITS */

  317.             shift = (i / 3);

  318.             mod = i % 3;

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

  320.         }

  321. 

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

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

  324.             int n, norm;

  325.             n = i + 2;

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

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

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

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

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

  331.                     i, norm,

  332.                     scale_factor_mult[i][0],

  333.                     scale_factor_mult[i][1],

  334.                     scale_factor_mult[i][2]);

  335.         }

  336. 

  337.         RENAME(ff_mpa_synth_init)(RENAME(ff_mpa_synth_window));

  338. 

  339.         /* huffman decode tables */

  340.         offset = 0;

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

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

  343.             int xsize, x, y;

  344.             uint8_t  tmp_bits [512];

  345.             uint16_t tmp_codes[512];

  346. 

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

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

  349. 

  350.             xsize = h->xsize;

  351. 

  352.             j = 0;

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

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

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

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

  357.                 }

  358.             }

  359. 

  360.             /* XXX: fail test */

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

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

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

  364.                      tmp_bits, 1, 1, tmp_codes, 2, 2,

  365.                      INIT_VLC_USE_NEW_STATIC);

  366.             offset += huff_vlc_tables_sizes[i];

  367.         }

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

  369. 

  370.         offset = 0;

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

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

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

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

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

  376.                      INIT_VLC_USE_NEW_STATIC);

  377.             offset += huff_quad_vlc_tables_sizes[i];

  378.         }

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

  380. 

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

  382.             k = 0;

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

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

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

  386.             }

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

  388.         }

  389. 

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

  391. 

  392.         int_pow_init();

  393.         mpegaudio_tableinit();

  394. 

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

  396.             if (ff_mpa_quant_bits[i] < 0)

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

  398.                     int val1, val2, val3, steps;

  399.                     int val = j;

  400.                     steps  = ff_mpa_quant_steps[i];

  401.                     val1 = val % steps;

  402.                     val /= steps;

  403.                     val2 = val % steps;

  404.                     val3 = val / steps;

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

  406.                 }

  407. 

  408. 

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

  410.             float f;

  411.             INTFLOAT v;

  412.             if (i != 6) {

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

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

  415.             } else {

  416.                 v = FIXR(1.0);

  417.             }

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

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

  420.         }

  421.         /* invalid values */

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

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

  424. 

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

  426.             double f;

  427.             int e, k;

  428. 

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

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

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

  432.                 k = i & 1;

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

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

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

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

  437.             }

  438.         }

  439. 

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

  441.             float ci, cs, ca;

  442.             ci = ci_table[i];

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

  444.             ca = cs * ci;

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

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

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

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

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

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

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

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

  453.         }

  454. 

  455.         /* compute mdct windows */

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

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

  458.                 double d;

  459. 

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

  461.                     continue;

  462. 

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

  464.                 if(j==1){

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

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

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

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

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

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

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

  472.                 }

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

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

  475. 

  476.                 if(j==2)

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

  478.                 else

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

  480.             }

  481.         }

  482. 

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

  484.            the sign of the right window coefs */

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

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

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

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

  489.             }

  490.         }

  491. 

  492.         init = 1;

  493.     }

  494. 

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

  496.         s->adu_mode = 1;

  497.     return 0;

  498. }

  499. 

  500. #define C3 FIXHR(0.86602540378443864676/2)

  501. 

  502. /* 0.5 / cos(pi*(2*i+1)/36) */

  503. static const INTFLOAT icos36[9] = {

  504.     FIXR(0.50190991877167369479),

  505.     FIXR(0.51763809020504152469), //0

  506.     FIXR(0.55168895948124587824),

  507.     FIXR(0.61038729438072803416),

  508.     FIXR(0.70710678118654752439), //1

  509.     FIXR(0.87172339781054900991),

  510.     FIXR(1.18310079157624925896),

  511.     FIXR(1.93185165257813657349), //2

  512.     FIXR(5.73685662283492756461),

  513. };

  514. 

  515. /* 0.5 / cos(pi*(2*i+1)/36) */

  516. static const INTFLOAT icos36h[9] = {

  517.     FIXHR(0.50190991877167369479/2),

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

  519.     FIXHR(0.55168895948124587824/2),

  520.     FIXHR(0.61038729438072803416/2),

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

  522.     FIXHR(0.87172339781054900991/2),

  523.     FIXHR(1.18310079157624925896/4),

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

  525. //    FIXHR(5.73685662283492756461),

  526. };

  527. 

  528. /* 12 points IMDCT. We compute it "by hand" by factorizing obvious

  529.    cases. */

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

  531. {

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

  533. 

  534.     in0= in[0*3];

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

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

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

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

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

  540.     in5 += in3;

  541.     in3 += in1;

  542. 

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

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

  545. 

  546.     t1 = in0 - in4;

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

  548. 

  549.     out[ 7]=

  550.     out[10]= t1 + t2;

  551.     out[ 1]=

  552.     out[ 4]= t1 - t2;

  553. 

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

  555.     in4 = in0 + in2;

  556.     in5 += 2*in1;

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

  558.     out[ 8]=

  559.     out[ 9]= in4 + in1;

  560.     out[ 2]=

  561.     out[ 3]= in4 - in1;

  562. 

  563.     in0 -= in2;

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

  565.     out[ 0]=

  566.     out[ 5]= in0 - in5;

  567.     out[ 6]=

  568.     out[11]= in0 + in5;

  569. }

  570. 

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

  572. #define C1 FIXHR(0.98480775301220805936/2)

  573. #define C2 FIXHR(0.93969262078590838405/2)

  574. #define C3 FIXHR(0.86602540378443864676/2)

  575. #define C4 FIXHR(0.76604444311897803520/2)

  576. #define C5 FIXHR(0.64278760968653932632/2)

  577. #define C6 FIXHR(0.5/2)

  578. #define C7 FIXHR(0.34202014332566873304/2)

  579. #define C8 FIXHR(0.17364817766693034885/2)

  580. 

  581. 

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

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

  584. {

  585.     int i, j;

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

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

  588. 

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

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

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

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

  593. 

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

  595.         tmp1 = tmp + j;

  596.         in1 = in + j;

  597. 

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

  599. 

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

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

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

  603.         tmp1[16] = t1 + t2;

  604. 

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

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

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

  608. 

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

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

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

  612. 

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

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

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

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

  617. 

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

  619. 

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

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

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

  623.     }

  624. 

  625.     i = 0;

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

  627.         t0 = tmp[i];

  628.         t1 = tmp[i + 2];

  629.         s0 = t1 + t0;

  630.         s2 = t1 - t0;

  631. 

  632.         t2 = tmp[i + 1];

  633.         t3 = tmp[i + 3];

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

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

  636. 

  637.         t0 = s0 + s1;

  638.         t1 = s0 - s1;

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

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

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

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

  643. 

  644.         t0 = s2 + s3;

  645.         t1 = s2 - s3;

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

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

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

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

  650.         i += 4;

  651.     }

  652. 

  653.     s0 = tmp[16];

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

  655.     t0 = s0 + s1;

  656.     t1 = s0 - s1;

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

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

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

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

  661. }

  662. 

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

  664. static int mp_decode_layer1(MPADecodeContext *s)

  665. {

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

  667.     uint8_t allocation[MPA_MAX_CHANNELS][SBLIMIT];

  668.     uint8_t scale_factors[MPA_MAX_CHANNELS][SBLIMIT];

  669. 

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

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

  672.     else

  673.         bound = SBLIMIT;

  674. 

  675.     /* allocation bits */

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

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

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

  679.         }

  680.     }

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

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

  683.     }

  684. 

  685.     /* scale factors */

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

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

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

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

  690.         }

  691.     }

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

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

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

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

  696.         }

  697.     }

  698. 

  699.     /* compute samples */

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

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

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

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

  704.                 if (n) {

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

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

  707.                 } else {

  708.                     v = 0;

  709.                 }

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

  711.             }

  712.         }

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

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

  715.             if (n) {

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

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

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

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

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

  721.             } else {

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

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

  724.             }

  725.         }

  726.     }

  727.     return 12;

  728. }

  729. 

  730. static int mp_decode_layer2(MPADecodeContext *s)

  731. {

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

  733.     const unsigned char *alloc_table;

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

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

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

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

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

  739. 

  740.     /* select decoding table */

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

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

  743.     sblimit = ff_mpa_sblimit_table[table];

  744.     alloc_table = ff_mpa_alloc_tables[table];

  745. 

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

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

  748.     else

  749.         bound = sblimit;

  750. 

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

  752. 

  753.     /* sanity check */

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

  755. 

  756.     /* parse bit allocation */

  757.     j = 0;

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

  759.         bit_alloc_bits = alloc_table[j];

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

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

  762.         }

  763.         j += 1 << bit_alloc_bits;

  764.     }

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

  766.         bit_alloc_bits = alloc_table[j];

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

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

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

  770.         j += 1 << bit_alloc_bits;

  771.     }

  772. 

  773.     /* scale codes */

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

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

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

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

  778.         }

  779.     }

  780. 

  781.     /* scale factors */

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

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

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

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

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

  787.                 default:

  788.                 case 0:

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

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

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

  792.                     break;

  793.                 case 2:

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

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

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

  797.                     break;

  798.                 case 1:

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

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

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

  802.                     break;

  803.                 case 3:

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

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

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

  807.                     break;

  808.                 }

  809.             }

  810.         }

  811.     }

  812. 

  813.     /* samples */

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

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

  816.             j = 0;

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

  818.                 bit_alloc_bits = alloc_table[j];

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

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

  821.                     if (b) {

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

  823.                         qindex = alloc_table[j+b];

  824.                         bits = ff_mpa_quant_bits[qindex];

  825.                         if (bits < 0) {

  826.                             int v2;

  827.                             /* 3 values at the same time */

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

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

  830.                             steps  = ff_mpa_quant_steps[qindex];

  831. 

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

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

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

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

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

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

  838.                         } else {

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

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

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

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

  843.                             }

  844.                         }

  845.                     } else {

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

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

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

  849.                     }

  850.                 }

  851.                 /* next subband in alloc table */

  852.                 j += 1 << bit_alloc_bits;

  853.             }

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

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

  856.                 bit_alloc_bits = alloc_table[j];

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

  858.                 if (b) {

  859.                     int mant, scale0, scale1;

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

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

  862.                     qindex = alloc_table[j+b];

  863.                     bits = ff_mpa_quant_bits[qindex];

  864.                     if (bits < 0) {

  865.                         /* 3 values at the same time */

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

  867.                         steps = ff_mpa_quant_steps[qindex];

  868.                         mant = v % steps;

  869.                         v = v / steps;

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

  871.                             l2_unscale_group(steps, mant, scale0);

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

  873.                             l2_unscale_group(steps, mant, scale1);

  874.                         mant = v % steps;

  875.                         v = v / steps;

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

  877.                             l2_unscale_group(steps, mant, scale0);

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

  879.                             l2_unscale_group(steps, mant, scale1);

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

  881.                             l2_unscale_group(steps, v, scale0);

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

  883.                             l2_unscale_group(steps, v, scale1);

  884.                     } else {

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

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

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

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

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

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

  891.                         }

  892.                     }

  893.                 } else {

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

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

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

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

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

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

  900.                 }

  901.                 /* next subband in alloc table */

  902.                 j += 1 << bit_alloc_bits;

  903.             }

  904.             /* fill remaining samples to zero */

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

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

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

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

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

  910.                 }

  911.             }

  912.         }

  913.     }

  914.     return 3 * 12;

  915. }

  916. 

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

  918.     if(n==3){\

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

  920.         dst= sf - 3*m;\

  921.         sf=m;\

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

  923.         dst= sf&3;\

  924.         sf>>=2;\

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

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

  927.         dst= sf - 5*m;\

  928.         sf=m;\

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

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

  931.         dst= sf - 6*m;\

  932.         sf=m;\

  933.     }else{\

  934.         dst=0;\

  935.     }

  936. 

  937. static av_always_inline void lsf_sf_expand(int *slen,

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

  939. {

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

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

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

  943.     slen[0] = sf;

  944. }

  945. 

  946. static void exponents_from_scale_factors(MPADecodeContext *s,

  947.                                          GranuleDef *g,

  948.                                          int16_t *exponents)

  949. {

  950.     const uint8_t *bstab, *pretab;

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

  952.     int16_t *exp_ptr;

  953. 

  954.     exp_ptr = exponents;

  955.     gain = g->global_gain - 210;

  956.     shift = g->scalefac_scale + 1;

  957. 

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

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

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

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

  962.         len = bstab[i];

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

  964.             *exp_ptr++ = v0;

  965.     }

  966. 

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

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

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

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

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

  972.         k = g->long_end;

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

  974.             len = bstab[i];

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

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

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

  978.                 *exp_ptr++ = v0;

  979.             }

  980.         }

  981.     }

  982. }

  983. 

  984. /* handle n = 0 too */

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

  986. {

  987.     if (n == 0)

  988.         return 0;

  989.     else

  990.         return get_bits(s, n);

  991. }

  992. 

  993. 

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

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

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

  997.         s->in_gb.buffer=NULL;

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

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

  1000.         *end_pos2=

  1001.         *end_pos= *end_pos2 + get_bits_count(&s->gb) - *pos;

  1002.         *pos= get_bits_count(&s->gb);

  1003.     }

  1004. }

  1005. 

  1006. /* Following is a optimized code for

  1007.             INTFLOAT v = *src

  1008.             if(get_bits1(&s->gb))

  1009.                 v = -v;

  1010.             *dst = v;

  1011. */

  1012. #if CONFIG_FLOAT

  1013. #define READ_FLIP_SIGN(dst,src)\

  1014.             v = AV_RN32A(src) ^ (get_bits1(&s->gb)<<31);\

  1015.             AV_WN32A(dst, v);

  1016. #else

  1017. #define READ_FLIP_SIGN(dst,src)\

  1018.             v= -get_bits1(&s->gb);\

  1019.             *(dst) = (*(src) ^ v) - v;

  1020. #endif

  1021. 

  1022. static int huffman_decode(MPADecodeContext *s, GranuleDef *g,

  1023.                           int16_t *exponents, int end_pos2)

  1024. {

  1025.     int s_index;

  1026.     int i;

  1027.     int last_pos, bits_left;

  1028.     VLC *vlc;

  1029.     int end_pos= FFMIN(end_pos2, s->gb.size_in_bits);

  1030. 

  1031.     /* low frequencies (called big values) */

  1032.     s_index = 0;

  1033.     for(i=0;i<3;i++) {

  1034.         int j, k, l, linbits;

  1035.         j = g->region_size[i];

  1036.         if (j == 0)

  1037.             continue;

  1038.         /* select vlc table */

  1039.         k = g->table_select[i];

  1040.         l = mpa_huff_data[k][0];

  1041.         linbits = mpa_huff_data[k][1];

  1042.         vlc = &huff_vlc[l];

  1043. 

  1044.         if(!l){

  1045.             memset(&g->sb_hybrid[s_index], 0, sizeof(*g->sb_hybrid)*2*j);

  1046.             s_index += 2*j;

  1047.             continue;

  1048.         }

  1049. 

  1050.         /* read huffcode and compute each couple */

  1051.         for(;j>0;j--) {

  1052.             int exponent, x, y;

  1053.             int v;

  1054.             int pos= get_bits_count(&s->gb);

  1055. 

  1056.             if (pos >= end_pos){

  1057. //                av_log(NULL, AV_LOG_ERROR, "pos: %d %d %d %d\n", pos, end_pos, end_pos2, s_index);

  1058.                 switch_buffer(s, &pos, &end_pos, &end_pos2);

  1059. //                av_log(NULL, AV_LOG_ERROR, "new pos: %d %d\n", pos, end_pos);

  1060.                 if(pos >= end_pos)

  1061.                     break;

  1062.             }

  1063.             y = get_vlc2(&s->gb, vlc->table, 7, 3);

  1064. 

  1065.             if(!y){

  1066.                 g->sb_hybrid[s_index  ] =

  1067.                 g->sb_hybrid[s_index+1] = 0;

  1068.                 s_index += 2;

  1069.                 continue;

  1070.             }

  1071. 

  1072.             exponent= exponents[s_index];

  1073. 

  1074.             av_dlog(s->avctx, "region=%d n=%d x=%d y=%d exp=%d\n",

  1075.                     i, g->region_size[i] - j, x, y, exponent);

  1076.             if(y&16){

  1077.                 x = y >> 5;

  1078.                 y = y & 0x0f;

  1079.                 if (x < 15){

  1080.                     READ_FLIP_SIGN(g->sb_hybrid+s_index, RENAME(expval_table)[ exponent ]+x)

  1081.                 }else{

  1082.                     x += get_bitsz(&s->gb, linbits);

  1083.                     v = l3_unscale(x, exponent);

  1084.                     if (get_bits1(&s->gb))

  1085.                         v = -v;

  1086.                     g->sb_hybrid[s_index] = v;

  1087.                 }

  1088.                 if (y < 15){

  1089.                     READ_FLIP_SIGN(g->sb_hybrid+s_index+1, RENAME(expval_table)[ exponent ]+y)

  1090.                 }else{

  1091.                     y += get_bitsz(&s->gb, linbits);

  1092.                     v = l3_unscale(y, exponent);

  1093.                     if (get_bits1(&s->gb))

  1094.                         v = -v;

  1095.                     g->sb_hybrid[s_index+1] = v;

  1096.                 }

  1097.             }else{

  1098.                 x = y >> 5;

  1099.                 y = y & 0x0f;

  1100.                 x += y;

  1101.                 if (x < 15){

  1102.                     READ_FLIP_SIGN(g->sb_hybrid+s_index+!!y, RENAME(expval_table)[ exponent ]+x)

  1103.                 }else{

  1104.                     x += get_bitsz(&s->gb, linbits);

  1105.                     v = l3_unscale(x, exponent);

  1106.                     if (get_bits1(&s->gb))

  1107.                         v = -v;

  1108.                     g->sb_hybrid[s_index+!!y] = v;

  1109.                 }

  1110.                 g->sb_hybrid[s_index+ !y] = 0;

  1111.             }

  1112.             s_index+=2;

  1113.         }

  1114.     }

  1115. 

  1116.     /* high frequencies */

  1117.     vlc = &huff_quad_vlc[g->count1table_select];

  1118.     last_pos=0;

  1119.     while (s_index <= 572) {

  1120.         int pos, code;

  1121.         pos = get_bits_count(&s->gb);

  1122.         if (pos >= end_pos) {

  1123.             if (pos > end_pos2 && last_pos){

  1124.                 /* some encoders generate an incorrect size for this

  1125.                    part. We must go back into the data */

  1126.                 s_index -= 4;

  1127.                 skip_bits_long(&s->gb, last_pos - pos);

  1128.                 av_log(s->avctx, AV_LOG_INFO, "overread, skip %d enddists: %d %d\n", last_pos - pos, end_pos-pos, end_pos2-pos);

  1129.                 if(s->error_recognition >= FF_ER_COMPLIANT)

  1130.                     s_index=0;

  1131.                 break;

  1132.             }

  1133. //                av_log(NULL, AV_LOG_ERROR, "pos2: %d %d %d %d\n", pos, end_pos, end_pos2, s_index);

  1134.             switch_buffer(s, &pos, &end_pos, &end_pos2);

  1135. //                av_log(NULL, AV_LOG_ERROR, "new pos2: %d %d %d\n", pos, end_pos, s_index);

  1136.             if(pos >= end_pos)

  1137.                 break;

  1138.         }

  1139.         last_pos= pos;

  1140. 

  1141.         code = get_vlc2(&s->gb, vlc->table, vlc->bits, 1);

  1142.         av_dlog(s->avctx, "t=%d code=%d\n", g->count1table_select, code);

  1143.         g->sb_hybrid[s_index+0]=

  1144.         g->sb_hybrid[s_index+1]=

  1145.         g->sb_hybrid[s_index+2]=

  1146.         g->sb_hybrid[s_index+3]= 0;

  1147.         while(code){

  1148.             static const int idxtab[16]={3,3,2,2,1,1,1,1,0,0,0,0,0,0,0,0};

  1149.             int v;

  1150.             int pos= s_index+idxtab[code];

  1151.             code ^= 8>>idxtab[code];

  1152.             READ_FLIP_SIGN(g->sb_hybrid+pos, RENAME(exp_table)+exponents[pos])

  1153.         }

  1154.         s_index+=4;

  1155.     }

  1156.     /* skip extension bits */

  1157.     bits_left = end_pos2 - get_bits_count(&s->gb);

  1158. //av_log(NULL, AV_LOG_ERROR, "left:%d buf:%p\n", bits_left, s->in_gb.buffer);

  1159.     if (bits_left < 0 && s->error_recognition >= FF_ER_COMPLIANT) {

  1160.         av_log(s->avctx, AV_LOG_ERROR, "bits_left=%d\n", bits_left);

  1161.         s_index=0;

  1162.     }else if(bits_left > 0 && s->error_recognition >= FF_ER_AGGRESSIVE){

  1163.         av_log(s->avctx, AV_LOG_ERROR, "bits_left=%d\n", bits_left);

  1164.         s_index=0;

  1165.     }

  1166.     memset(&g->sb_hybrid[s_index], 0, sizeof(*g->sb_hybrid)*(576 - s_index));

  1167.     skip_bits_long(&s->gb, bits_left);

  1168. 

  1169.     i= get_bits_count(&s->gb);

  1170.     switch_buffer(s, &i, &end_pos, &end_pos2);

  1171. 

  1172.     return 0;

  1173. }

  1174. 

  1175. /* Reorder short blocks from bitstream order to interleaved order. It

  1176.    would be faster to do it in parsing, but the code would be far more

  1177.    complicated */

  1178. static void reorder_block(MPADecodeContext *s, GranuleDef *g)

  1179. {

  1180.     int i, j, len;

  1181.     INTFLOAT *ptr, *dst, *ptr1;

  1182.     INTFLOAT tmp[576];

  1183. 

  1184.     if (g->block_type != 2)

  1185.         return;

  1186. 

  1187.     if (g->switch_point) {

  1188.         if (s->sample_rate_index != 8) {

  1189.             ptr = g->sb_hybrid + 36;

  1190.         } else {

  1191.             ptr = g->sb_hybrid + 48;

  1192.         }

  1193.     } else {

  1194.         ptr = g->sb_hybrid;

  1195.     }

  1196. 

  1197.     for(i=g->short_start;i<13;i++) {

  1198.         len = band_size_short[s->sample_rate_index][i];

  1199.         ptr1 = ptr;

  1200.         dst = tmp;

  1201.         for(j=len;j>0;j--) {

  1202.             *dst++ = ptr[0*len];

  1203.             *dst++ = ptr[1*len];

  1204.             *dst++ = ptr[2*len];

  1205.             ptr++;

  1206.         }

  1207.         ptr+=2*len;

  1208.         memcpy(ptr1, tmp, len * 3 * sizeof(*ptr1));

  1209.     }

  1210. }

  1211. 

  1212. #define ISQRT2 FIXR(0.70710678118654752440)

  1213. 

  1214. static void compute_stereo(MPADecodeContext *s,

  1215.                            GranuleDef *g0, GranuleDef *g1)

  1216. {

  1217.     int i, j, k, l;

  1218.     int sf_max, sf, len, non_zero_found;

  1219.     INTFLOAT (*is_tab)[16], *tab0, *tab1, tmp0, tmp1, v1, v2;

  1220.     int non_zero_found_short[3];

  1221. 

  1222.     /* intensity stereo */

  1223.     if (s->mode_ext & MODE_EXT_I_STEREO) {

  1224.         if (!s->lsf) {

  1225.             is_tab = is_table;

  1226.             sf_max = 7;

  1227.         } else {

  1228.             is_tab = is_table_lsf[g1->scalefac_compress & 1];

  1229.             sf_max = 16;

  1230.         }

  1231. 

  1232.         tab0 = g0->sb_hybrid + 576;

  1233.         tab1 = g1->sb_hybrid + 576;

  1234. 

  1235.         non_zero_found_short[0] = 0;

  1236.         non_zero_found_short[1] = 0;

  1237.         non_zero_found_short[2] = 0;

  1238.         k = (13 - g1->short_start) * 3 + g1->long_end - 3;

  1239.         for(i = 12;i >= g1->short_start;i--) {

  1240.             /* for last band, use previous scale factor */

  1241.             if (i != 11)

  1242.                 k -= 3;

  1243.             len = band_size_short[s->sample_rate_index][i];

  1244.             for(l=2;l>=0;l--) {

  1245.                 tab0 -= len;

  1246.                 tab1 -= len;

  1247.                 if (!non_zero_found_short[l]) {

  1248.                     /* test if non zero band. if so, stop doing i-stereo */

  1249.                     for(j=0;j<len;j++) {

  1250.                         if (tab1[j] != 0) {

  1251.                             non_zero_found_short[l] = 1;

  1252.                             goto found1;

  1253.                         }

  1254.                     }

  1255.                     sf = g1->scale_factors[k + l];

  1256.                     if (sf >= sf_max)

  1257.                         goto found1;

  1258. 

  1259.                     v1 = is_tab[0][sf];

  1260.                     v2 = is_tab[1][sf];

  1261.                     for(j=0;j<len;j++) {

  1262.                         tmp0 = tab0[j];

  1263.                         tab0[j] = MULLx(tmp0, v1, FRAC_BITS);

  1264.                         tab1[j] = MULLx(tmp0, v2, FRAC_BITS);

  1265.                     }

  1266.                 } else {

  1267.                 found1:

  1268.                     if (s->mode_ext & MODE_EXT_MS_STEREO) {

  1269.                         /* lower part of the spectrum : do ms stereo

  1270.                            if enabled */

  1271.                         for(j=0;j<len;j++) {

  1272.                             tmp0 = tab0[j];

  1273.                             tmp1 = tab1[j];

  1274.                             tab0[j] = MULLx(tmp0 + tmp1, ISQRT2, FRAC_BITS);

  1275.                             tab1[j] = MULLx(tmp0 - tmp1, ISQRT2, FRAC_BITS);

  1276.                         }

  1277.                     }

  1278.                 }

  1279.             }

  1280.         }

  1281. 

  1282.         non_zero_found = non_zero_found_short[0] |

  1283.             non_zero_found_short[1] |

  1284.             non_zero_found_short[2];

  1285. 

  1286.         for(i = g1->long_end - 1;i >= 0;i--) {

  1287.             len = band_size_long[s->sample_rate_index][i];

  1288.             tab0 -= len;

  1289.             tab1 -= len;

  1290.             /* test if non zero band. if so, stop doing i-stereo */

  1291.             if (!non_zero_found) {

  1292.                 for(j=0;j<len;j++) {

  1293.                     if (tab1[j] != 0) {

  1294.                         non_zero_found = 1;

  1295.                         goto found2;

  1296.                     }

  1297.                 }

  1298.                 /* for last band, use previous scale factor */

  1299.                 k = (i == 21) ? 20 : i;

  1300.                 sf = g1->scale_factors[k];

  1301.                 if (sf >= sf_max)

  1302.                     goto found2;

  1303.                 v1 = is_tab[0][sf];

  1304.                 v2 = is_tab[1][sf];

  1305.                 for(j=0;j<len;j++) {

  1306.                     tmp0 = tab0[j];

  1307.                     tab0[j] = MULLx(tmp0, v1, FRAC_BITS);

  1308.                     tab1[j] = MULLx(tmp0, v2, FRAC_BITS);

  1309.                 }

  1310.             } else {

  1311.             found2:

  1312.                 if (s->mode_ext & MODE_EXT_MS_STEREO) {

  1313.                     /* lower part of the spectrum : do ms stereo

  1314.                        if enabled */

  1315.                     for(j=0;j<len;j++) {

  1316.                         tmp0 = tab0[j];

  1317.                         tmp1 = tab1[j];

  1318.                         tab0[j] = MULLx(tmp0 + tmp1, ISQRT2, FRAC_BITS);

  1319.                         tab1[j] = MULLx(tmp0 - tmp1, ISQRT2, FRAC_BITS);

  1320.                     }

  1321.                 }

  1322.             }

  1323.         }

  1324.     } else if (s->mode_ext & MODE_EXT_MS_STEREO) {

  1325.         /* ms stereo ONLY */

  1326.         /* NOTE: the 1/sqrt(2) normalization factor is included in the

  1327.            global gain */

  1328.         tab0 = g0->sb_hybrid;

  1329.         tab1 = g1->sb_hybrid;

  1330.         for(i=0;i<576;i++) {

  1331.             tmp0 = tab0[i];

  1332.             tmp1 = tab1[i];

  1333.             tab0[i] = tmp0 + tmp1;

  1334.             tab1[i] = tmp0 - tmp1;

  1335.         }

  1336.     }

  1337. }

  1338. 

  1339. #if !CONFIG_FLOAT

  1340. static void compute_antialias_fixed(MPADecodeContext *s, GranuleDef *g)

  1341. {

  1342.     int32_t *ptr, *csa;

  1343.     int n, i;

  1344. 

  1345.     /* we antialias only "long" bands */

  1346.     if (g->block_type == 2) {

  1347.         if (!g->switch_point)

  1348.             return;

  1349.         /* XXX: check this for 8000Hz case */

  1350.         n = 1;

  1351.     } else {

  1352.         n = SBLIMIT - 1;

  1353.     }

  1354. 

  1355.     ptr = g->sb_hybrid + 18;

  1356.     for(i = n;i > 0;i--) {

  1357.         int tmp0, tmp1, tmp2;

  1358.         csa = &csa_table[0][0];

  1359. #define INT_AA(j) \

  1360.             tmp0 = ptr[-1-j];\

  1361.             tmp1 = ptr[   j];\

  1362.             tmp2= MULH(tmp0 + tmp1, csa[0+4*j]);\

  1363.             ptr[-1-j] = 4*(tmp2 - MULH(tmp1, csa[2+4*j]));\

  1364.             ptr[   j] = 4*(tmp2 + MULH(tmp0, csa[3+4*j]));

  1365. 

  1366.         INT_AA(0)

  1367.         INT_AA(1)

  1368.         INT_AA(2)

  1369.         INT_AA(3)

  1370.         INT_AA(4)

  1371.         INT_AA(5)

  1372.         INT_AA(6)

  1373.         INT_AA(7)

  1374. 

  1375.         ptr += 18;

  1376.     }

  1377. }

  1378. #endif

  1379. 

  1380. static void compute_imdct(MPADecodeContext *s,

  1381.                           GranuleDef *g,

  1382.                           INTFLOAT *sb_samples,

  1383.                           INTFLOAT *mdct_buf)

  1384. {

  1385.     INTFLOAT *win, *win1, *out_ptr, *ptr, *buf, *ptr1;

  1386.     INTFLOAT out2[12];

  1387.     int i, j, mdct_long_end, sblimit;

  1388. 

  1389.     /* find last non zero block */

  1390.     ptr = g->sb_hybrid + 576;

  1391.     ptr1 = g->sb_hybrid + 2 * 18;

  1392.     while (ptr >= ptr1) {

  1393.         int32_t *p;

  1394.         ptr -= 6;

  1395.         p= (int32_t*)ptr;

  1396.         if(p[0] | p[1] | p[2] | p[3] | p[4] | p[5])

  1397.             break;

  1398.     }

  1399.     sblimit = ((ptr - g->sb_hybrid) / 18) + 1;

  1400. 

  1401.     if (g->block_type == 2) {

  1402.         /* XXX: check for 8000 Hz */

  1403.         if (g->switch_point)

  1404.             mdct_long_end = 2;

  1405.         else

  1406.             mdct_long_end = 0;

  1407.     } else {

  1408.         mdct_long_end = sblimit;

  1409.     }

  1410. 

  1411.     buf = mdct_buf;

  1412.     ptr = g->sb_hybrid;

  1413.     for(j=0;j<mdct_long_end;j++) {

  1414.         /* apply window & overlap with previous buffer */

  1415.         out_ptr = sb_samples + j;

  1416.         /* select window */

  1417.         if (g->switch_point && j < 2)

  1418.             win1 = mdct_win[0];

  1419.         else

  1420.             win1 = mdct_win[g->block_type];

  1421.         /* select frequency inversion */

  1422.         win = win1 + ((4 * 36) & -(j & 1));

  1423.         imdct36(out_ptr, buf, ptr, win);

  1424.         out_ptr += 18*SBLIMIT;

  1425.         ptr += 18;

  1426.         buf += 18;

  1427.     }

  1428.     for(j=mdct_long_end;j<sblimit;j++) {

  1429.         /* select frequency inversion */

  1430.         win = mdct_win[2] + ((4 * 36) & -(j & 1));

  1431.         out_ptr = sb_samples + j;

  1432. 

  1433.         for(i=0; i<6; i++){

  1434.             *out_ptr = buf[i];

  1435.             out_ptr += SBLIMIT;

  1436.         }

  1437.         imdct12(out2, ptr + 0);

  1438.         for(i=0;i<6;i++) {

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

  1440.             buf[i + 6*2] = MULH3(out2[i + 6], win[i + 6], 1);

  1441.             out_ptr += SBLIMIT;

  1442.         }

  1443.         imdct12(out2, ptr + 1);

  1444.         for(i=0;i<6;i++) {

  1445.             *out_ptr     = MULH3(out2[i    ], win[i    ], 1) + buf[i + 6*2];

  1446.             buf[i + 6*0] = MULH3(out2[i + 6], win[i + 6], 1);

  1447.             out_ptr += SBLIMIT;

  1448.         }

  1449.         imdct12(out2, ptr + 2);

  1450.         for(i=0;i<6;i++) {

  1451.             buf[i + 6*0] = MULH3(out2[i    ], win[i    ], 1) + buf[i + 6*0];

  1452.             buf[i + 6*1] = MULH3(out2[i + 6], win[i + 6], 1);

  1453.             buf[i + 6*2] = 0;

  1454.         }

  1455.         ptr += 18;

  1456.         buf += 18;

  1457.     }

  1458.     /* zero bands */

  1459.     for(j=sblimit;j<SBLIMIT;j++) {

  1460.         /* overlap */

  1461.         out_ptr = sb_samples + j;

  1462.         for(i=0;i<18;i++) {

  1463.             *out_ptr = buf[i];

  1464.             buf[i] = 0;

  1465.             out_ptr += SBLIMIT;

  1466.         }

  1467.         buf += 18;

  1468.     }

  1469. }

  1470. 

  1471. /* main layer3 decoding function */

  1472. static int mp_decode_layer3(MPADecodeContext *s)

  1473. {

  1474.     int nb_granules, main_data_begin, private_bits;

  1475.     int gr, ch, blocksplit_flag, i, j, k, n, bits_pos;

  1476.     GranuleDef *g;

  1477.     int16_t exponents[576]; //FIXME try INTFLOAT

  1478. 

  1479.     /* read side info */

  1480.     if (s->lsf) {

  1481.         main_data_begin = get_bits(&s->gb, 8);

  1482.         private_bits = get_bits(&s->gb, s->nb_channels);

  1483.         nb_granules = 1;

  1484.     } else {

  1485.         main_data_begin = get_bits(&s->gb, 9);

  1486.         if (s->nb_channels == 2)

  1487.             private_bits = get_bits(&s->gb, 3);

  1488.         else

  1489.             private_bits = get_bits(&s->gb, 5);

  1490.         nb_granules = 2;

  1491.         for(ch=0;ch<s->nb_channels;ch++) {

  1492.             s->granules[ch][0].scfsi = 0;/* all scale factors are transmitted */

  1493.             s->granules[ch][1].scfsi = get_bits(&s->gb, 4);

  1494.         }

  1495.     }

  1496. 

  1497.     for(gr=0;gr<nb_granules;gr++) {

  1498.         for(ch=0;ch<s->nb_channels;ch++) {

  1499.             av_dlog(s->avctx, "gr=%d ch=%d: side_info\n", gr, ch);

  1500.             g = &s->granules[ch][gr];

  1501.             g->part2_3_length = get_bits(&s->gb, 12);

  1502.             g->big_values = get_bits(&s->gb, 9);

  1503.             if(g->big_values > 288){

  1504.                 av_log(s->avctx, AV_LOG_ERROR, "big_values too big\n");

  1505.                 return -1;

  1506.             }

  1507. 

  1508.             g->global_gain = get_bits(&s->gb, 8);

  1509.             /* if MS stereo only is selected, we precompute the

  1510.                1/sqrt(2) renormalization factor */

  1511.             if ((s->mode_ext & (MODE_EXT_MS_STEREO | MODE_EXT_I_STEREO)) ==

  1512.                 MODE_EXT_MS_STEREO)

  1513.                 g->global_gain -= 2;

  1514.             if (s->lsf)

  1515.                 g->scalefac_compress = get_bits(&s->gb, 9);

  1516.             else

  1517.                 g->scalefac_compress = get_bits(&s->gb, 4);

  1518.             blocksplit_flag = get_bits1(&s->gb);

  1519.             if (blocksplit_flag) {

  1520.                 g->block_type = get_bits(&s->gb, 2);

  1521.                 if (g->block_type == 0){

  1522.                     av_log(s->avctx, AV_LOG_ERROR, "invalid block type\n");

  1523.                     return -1;

  1524.                 }

  1525.                 g->switch_point = get_bits1(&s->gb);

  1526.                 for(i=0;i<2;i++)

  1527.                     g->table_select[i] = get_bits(&s->gb, 5);

  1528.                 for(i=0;i<3;i++)

  1529.                     g->subblock_gain[i] = get_bits(&s->gb, 3);

  1530.                 ff_init_short_region(s, g);

  1531.             } else {

  1532.                 int region_address1, region_address2;

  1533.                 g->block_type = 0;

  1534.                 g->switch_point = 0;

  1535.                 for(i=0;i<3;i++)

  1536.                     g->table_select[i] = get_bits(&s->gb, 5);

  1537.                 /* compute huffman coded region sizes */

  1538.                 region_address1 = get_bits(&s->gb, 4);

  1539.                 region_address2 = get_bits(&s->gb, 3);

  1540.                 av_dlog(s->avctx, "region1=%d region2=%d\n",

  1541.                         region_address1, region_address2);

  1542.                 ff_init_long_region(s, g, region_address1, region_address2);

  1543.             }

  1544.             ff_region_offset2size(g);

  1545.             ff_compute_band_indexes(s, g);

  1546. 

  1547.             g->preflag = 0;

  1548.             if (!s->lsf)

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

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

  1551.             g->count1table_select = get_bits1(&s->gb);

  1552.             av_dlog(s->avctx, "block_type=%d switch_point=%d\n",

  1553.                     g->block_type, g->switch_point);

  1554.         }

  1555.     }

  1556. 

  1557.   if (!s->adu_mode) {

  1558.     const uint8_t *ptr = s->gb.buffer + (get_bits_count(&s->gb)>>3);

  1559.     assert((get_bits_count(&s->gb) & 7) == 0);

  1560.     /* now we get bits from the main_data_begin offset */

  1561.     av_dlog(s->avctx, "seekback: %d\n", main_data_begin);

  1562. //av_log(NULL, AV_LOG_ERROR, "backstep:%d, lastbuf:%d\n", main_data_begin, s->last_buf_size);

  1563. 

  1564.     memcpy(s->last_buf + s->last_buf_size, ptr, EXTRABYTES);

  1565.     s->in_gb= s->gb;

  1566.         init_get_bits(&s->gb, s->last_buf, s->last_buf_size*8);

  1567.         skip_bits_long(&s->gb, 8*(s->last_buf_size - main_data_begin));

  1568.   }

  1569. 

  1570.     for(gr=0;gr<nb_granules;gr++) {

  1571.         for(ch=0;ch<s->nb_channels;ch++) {

  1572.             g = &s->granules[ch][gr];

  1573.             if(get_bits_count(&s->gb)<0){

  1574.                 av_log(s->avctx, AV_LOG_DEBUG, "mdb:%d, lastbuf:%d skipping granule %d\n",

  1575.                                             main_data_begin, s->last_buf_size, gr);

  1576.                 skip_bits_long(&s->gb, g->part2_3_length);

  1577.                 memset(g->sb_hybrid, 0, sizeof(g->sb_hybrid));

  1578.                 if(get_bits_count(&s->gb) >= s->gb.size_in_bits && s->in_gb.buffer){

  1579.                     skip_bits_long(&s->in_gb, get_bits_count(&s->gb) - s->gb.size_in_bits);

  1580.                     s->gb= s->in_gb;

  1581.                     s->in_gb.buffer=NULL;

  1582.                 }

  1583.                 continue;

  1584.             }

  1585. 

  1586.             bits_pos = get_bits_count(&s->gb);

  1587. 

  1588.             if (!s->lsf) {

  1589.                 uint8_t *sc;

  1590.                 int slen, slen1, slen2;

  1591. 

  1592.                 /* MPEG1 scale factors */

  1593.                 slen1 = slen_table[0][g->scalefac_compress];

  1594.                 slen2 = slen_table[1][g->scalefac_compress];

  1595.                 av_dlog(s->avctx, "slen1=%d slen2=%d\n", slen1, slen2);

  1596.                 if (g->block_type == 2) {

  1597.                     n = g->switch_point ? 17 : 18;

  1598.                     j = 0;

  1599.                     if(slen1){

  1600.                         for(i=0;i<n;i++)

  1601.                             g->scale_factors[j++] = get_bits(&s->gb, slen1);

  1602.                     }else{

  1603.                         for(i=0;i<n;i++)

  1604.                             g->scale_factors[j++] = 0;

  1605.                     }

  1606.                     if(slen2){

  1607.                         for(i=0;i<18;i++)

  1608.                             g->scale_factors[j++] = get_bits(&s->gb, slen2);

  1609.                         for(i=0;i<3;i++)

  1610.                             g->scale_factors[j++] = 0;

  1611.                     }else{

  1612.                         for(i=0;i<21;i++)

  1613.                             g->scale_factors[j++] = 0;

  1614.                     }

  1615.                 } else {

  1616.                     sc = s->granules[ch][0].scale_factors;

  1617.                     j = 0;

  1618.                     for(k=0;k<4;k++) {

  1619.                         n = (k == 0 ? 6 : 5);

  1620.                         if ((g->scfsi & (0x8 >> k)) == 0) {

  1621.                             slen = (k < 2) ? slen1 : slen2;

  1622.                             if(slen){

  1623.                                 for(i=0;i<n;i++)

  1624.                                     g->scale_factors[j++] = get_bits(&s->gb, slen);

  1625.                             }else{

  1626.                                 for(i=0;i<n;i++)

  1627.                                     g->scale_factors[j++] = 0;

  1628.                             }

  1629.                         } else {

  1630.                             /* simply copy from last granule */

  1631.                             for(i=0;i<n;i++) {

  1632.                                 g->scale_factors[j] = sc[j];

  1633.                                 j++;

  1634.                             }

  1635.                         }

  1636.                     }

  1637.                     g->scale_factors[j++] = 0;

  1638.                 }

  1639.             } else {

  1640.                 int tindex, tindex2, slen[4], sl, sf;

  1641. 

  1642.                 /* LSF scale factors */

  1643.                 if (g->block_type == 2) {

  1644.                     tindex = g->switch_point ? 2 : 1;

  1645.                 } else {

  1646.                     tindex = 0;

  1647.                 }

  1648.                 sf = g->scalefac_compress;

  1649.                 if ((s->mode_ext & MODE_EXT_I_STEREO) && ch == 1) {

  1650.                     /* intensity stereo case */

  1651.                     sf >>= 1;

  1652.                     if (sf < 180) {

  1653.                         lsf_sf_expand(slen, sf, 6, 6, 0);

  1654.                         tindex2 = 3;

  1655.                     } else if (sf < 244) {

  1656.                         lsf_sf_expand(slen, sf - 180, 4, 4, 0);

  1657.                         tindex2 = 4;

  1658.                     } else {

  1659.                         lsf_sf_expand(slen, sf - 244, 3, 0, 0);

  1660.                         tindex2 = 5;

  1661.                     }

  1662.                 } else {

  1663.                     /* normal case */

  1664.                     if (sf < 400) {

  1665.                         lsf_sf_expand(slen, sf, 5, 4, 4);

  1666.                         tindex2 = 0;

  1667.                     } else if (sf < 500) {

  1668.                         lsf_sf_expand(slen, sf - 400, 5, 4, 0);

  1669.                         tindex2 = 1;

  1670.                     } else {

  1671.                         lsf_sf_expand(slen, sf - 500, 3, 0, 0);

  1672.                         tindex2 = 2;

  1673.                         g->preflag = 1;

  1674.                     }

  1675.                 }

  1676. 

  1677.                 j = 0;

  1678.                 for(k=0;k<4;k++) {

  1679.                     n = lsf_nsf_table[tindex2][tindex][k];

  1680.                     sl = slen[k];

  1681.                     if(sl){

  1682.                         for(i=0;i<n;i++)

  1683.                             g->scale_factors[j++] = get_bits(&s->gb, sl);

  1684.                     }else{

  1685.                         for(i=0;i<n;i++)

  1686.                             g->scale_factors[j++] = 0;

  1687.                     }

  1688.                 }

  1689.                 /* XXX: should compute exact size */

  1690.                 for(;j<40;j++)

  1691.                     g->scale_factors[j] = 0;

  1692.             }

  1693. 

  1694.             exponents_from_scale_factors(s, g, exponents);

  1695. 

  1696.             /* read Huffman coded residue */

  1697.             huffman_decode(s, g, exponents, bits_pos + g->part2_3_length);

  1698.         } /* ch */

  1699. 

  1700.         if (s->nb_channels == 2)

  1701.             compute_stereo(s, &s->granules[0][gr], &s->granules[1][gr]);

  1702. 

  1703.         for(ch=0;ch<s->nb_channels;ch++) {

  1704.             g = &s->granules[ch][gr];

  1705. 

  1706.             reorder_block(s, g);

  1707.             RENAME(compute_antialias)(s, g);

  1708.             compute_imdct(s, g, &s->sb_samples[ch][18 * gr][0], s->mdct_buf[ch]);

  1709.         }

  1710.     } /* gr */

  1711.     if(get_bits_count(&s->gb)<0)

  1712.         skip_bits_long(&s->gb, -get_bits_count(&s->gb));

  1713.     return nb_granules * 18;

  1714. }

  1715. 

  1716. static int mp_decode_frame(MPADecodeContext *s,

  1717.                            OUT_INT *samples, const uint8_t *buf, int buf_size)

  1718. {

  1719.     int i, nb_frames, ch;

  1720.     OUT_INT *samples_ptr;

  1721. 

  1722.     init_get_bits(&s->gb, buf + HEADER_SIZE, (buf_size - HEADER_SIZE)*8);

  1723. 

  1724.     /* skip error protection field */

  1725.     if (s->error_protection)

  1726.         skip_bits(&s->gb, 16);

  1727. 

  1728.     av_dlog(s->avctx, "frame %d:\n", s->frame_count);

  1729.     switch(s->layer) {

  1730.     case 1:

  1731.         s->avctx->frame_size = 384;

  1732.         nb_frames = mp_decode_layer1(s);

  1733.         break;

  1734.     case 2:

  1735.         s->avctx->frame_size = 1152;

  1736.         nb_frames = mp_decode_layer2(s);

  1737.         break;

  1738.     case 3:

  1739.         s->avctx->frame_size = s->lsf ? 576 : 1152;

  1740.     default:

  1741.         nb_frames = mp_decode_layer3(s);

  1742. 

  1743.         s->last_buf_size=0;

  1744.         if(s->in_gb.buffer){

  1745.             align_get_bits(&s->gb);

  1746.             i= get_bits_left(&s->gb)>>3;

  1747.             if(i >= 0 && i <= BACKSTEP_SIZE){

  1748.                 memmove(s->last_buf, s->gb.buffer + (get_bits_count(&s->gb)>>3), i);

  1749.                 s->last_buf_size=i;

  1750.             }else

  1751.                 av_log(s->avctx, AV_LOG_ERROR, "invalid old backstep %d\n", i);

  1752.             s->gb= s->in_gb;

  1753.             s->in_gb.buffer= NULL;

  1754.         }

  1755. 

  1756.         align_get_bits(&s->gb);

  1757.         assert((get_bits_count(&s->gb) & 7) == 0);

  1758.         i= get_bits_left(&s->gb)>>3;

  1759. 

  1760.         if(i<0 || i > BACKSTEP_SIZE || nb_frames<0){

  1761.             if(i<0)

  1762.                 av_log(s->avctx, AV_LOG_ERROR, "invalid new backstep %d\n", i);

  1763.             i= FFMIN(BACKSTEP_SIZE, buf_size - HEADER_SIZE);

  1764.         }

  1765.         assert(i <= buf_size - HEADER_SIZE && i>= 0);

  1766.         memcpy(s->last_buf + s->last_buf_size, s->gb.buffer + buf_size - HEADER_SIZE - i, i);

  1767.         s->last_buf_size += i;

  1768. 

  1769.         break;

  1770.     }

  1771. 

  1772.     /* apply the synthesis filter */

  1773.     for(ch=0;ch<s->nb_channels;ch++) {

  1774.         samples_ptr = samples + ch;

  1775.         for(i=0;i<nb_frames;i++) {

  1776.             RENAME(ff_mpa_synth_filter)(

  1777.                          &s->mpadsp,

  1778.                          s->synth_buf[ch], &(s->synth_buf_offset[ch]),

  1779.                          RENAME(ff_mpa_synth_window), &s->dither_state,

  1780.                          samples_ptr, s->nb_channels,

  1781.                          s->sb_samples[ch][i]);

  1782.             samples_ptr += 32 * s->nb_channels;

  1783.         }

  1784.     }

  1785. 

  1786.     return nb_frames * 32 * sizeof(OUT_INT) * s->nb_channels;

  1787. }

  1788. 

  1789. static int decode_frame(AVCodecContext * avctx,

  1790.                         void *data, int *data_size,

  1791.                         AVPacket *avpkt)

  1792. {

  1793.     const uint8_t *buf = avpkt->data;

  1794.     int buf_size = avpkt->size;

  1795.     MPADecodeContext *s = avctx->priv_data;

  1796.     uint32_t header;

  1797.     int out_size;

  1798.     OUT_INT *out_samples = data;

  1799. 

  1800.     if(buf_size < HEADER_SIZE)

  1801.         return -1;

  1802. 

  1803.     header = AV_RB32(buf);

  1804.     if(ff_mpa_check_header(header) < 0){

  1805.         av_log(avctx, AV_LOG_ERROR, "Header missing\n");

  1806.         return -1;

  1807.     }

  1808. 

  1809.     if (ff_mpegaudio_decode_header((MPADecodeHeader *)s, header) == 1) {

  1810.         /* free format: prepare to compute frame size */

  1811.         s->frame_size = -1;

  1812.         return -1;

  1813.     }

  1814.     /* update codec info */

  1815.     avctx->channels = s->nb_channels;

  1816.     avctx->channel_layout = s->nb_channels == 1 ? AV_CH_LAYOUT_MONO : AV_CH_LAYOUT_STEREO;

  1817.     if (!avctx->bit_rate)

  1818.         avctx->bit_rate = s->bit_rate;

  1819.     avctx->sub_id = s->layer;

  1820. 

  1821.     if(*data_size < 1152*avctx->channels*sizeof(OUT_INT))

  1822.         return -1;

  1823.     *data_size = 0;

  1824. 

  1825.     if(s->frame_size<=0 || s->frame_size > buf_size){

  1826.         av_log(avctx, AV_LOG_ERROR, "incomplete frame\n");

  1827.         return -1;

  1828.     }else if(s->frame_size < buf_size){

  1829.         av_log(avctx, AV_LOG_ERROR, "incorrect frame size\n");

  1830.         buf_size= s->frame_size;

  1831.     }

  1832. 

  1833.     out_size = mp_decode_frame(s, out_samples, buf, buf_size);

  1834.     if(out_size>=0){

  1835.         *data_size = out_size;

  1836.         avctx->sample_rate = s->sample_rate;

  1837.         //FIXME maybe move the other codec info stuff from above here too

  1838.     }else

  1839.         av_log(avctx, AV_LOG_DEBUG, "Error while decoding MPEG audio frame.\n"); //FIXME return -1 / but also return the number of bytes consumed

  1840.     s->frame_size = 0;

  1841.     return buf_size;

  1842. }

  1843. 

  1844. static void flush(AVCodecContext *avctx){

  1845.     MPADecodeContext *s = avctx->priv_data;

  1846.     memset(s->synth_buf, 0, sizeof(s->synth_buf));

  1847.     s->last_buf_size= 0;

  1848. }

  1849. 

  1850. #if CONFIG_MP3ADU_DECODER || CONFIG_MP3ADUFLOAT_DECODER

  1851. static int decode_frame_adu(AVCodecContext * avctx,

  1852.                         void *data, int *data_size,

  1853.                         AVPacket *avpkt)

  1854. {

  1855.     const uint8_t *buf = avpkt->data;

  1856.     int buf_size = avpkt->size;

  1857.     MPADecodeContext *s = avctx->priv_data;

  1858.     uint32_t header;

  1859.     int len, out_size;

  1860.     OUT_INT *out_samples = data;

  1861. 

  1862.     len = buf_size;

  1863. 

  1864.     // Discard too short frames

  1865.     if (buf_size < HEADER_SIZE) {

  1866.         *data_size = 0;

  1867.         return buf_size;

  1868.     }

  1869. 

  1870. 

  1871.     if (len > MPA_MAX_CODED_FRAME_SIZE)

  1872.         len = MPA_MAX_CODED_FRAME_SIZE;

  1873. 

  1874.     // Get header and restore sync word

  1875.     header = AV_RB32(buf) | 0xffe00000;

  1876. 

  1877.     if (ff_mpa_check_header(header) < 0) { // Bad header, discard frame

  1878.         *data_size = 0;

  1879.         return buf_size;

  1880.     }

  1881. 

  1882.     ff_mpegaudio_decode_header((MPADecodeHeader *)s, header);

  1883.     /* update codec info */

  1884.     avctx->sample_rate = s->sample_rate;

  1885.     avctx->channels = s->nb_channels;

  1886.     if (!avctx->bit_rate)

  1887.         avctx->bit_rate = s->bit_rate;

  1888.     avctx->sub_id = s->layer;

  1889. 

  1890.     s->frame_size = len;

  1891. 

  1892.     if (avctx->parse_only) {

  1893.         out_size = buf_size;

  1894.     } else {

  1895.         out_size = mp_decode_frame(s, out_samples, buf, buf_size);

  1896.     }

  1897. 

  1898.     *data_size = out_size;

  1899.     return buf_size;

  1900. }

  1901. #endif /* CONFIG_MP3ADU_DECODER || CONFIG_MP3ADUFLOAT_DECODER */

  1902. 

  1903. #if CONFIG_MP3ON4_DECODER || CONFIG_MP3ON4FLOAT_DECODER

  1904. 

  1905. /**

  1906.  * Context for MP3On4 decoder

  1907.  */

  1908. typedef struct MP3On4DecodeContext {

  1909.     int frames;   ///< number of mp3 frames per block (number of mp3 decoder instances)

  1910.     int syncword; ///< syncword patch

  1911.     const uint8_t *coff; ///< channels offsets in output buffer

  1912.     MPADecodeContext *mp3decctx[5]; ///< MPADecodeContext for every decoder instance

  1913. } MP3On4DecodeContext;

  1914. 

  1915. #include "mpeg4audio.h"

  1916. 

  1917. /* Next 3 arrays are indexed by channel config number (passed via codecdata) */

  1918. static const uint8_t mp3Frames[8] = {0,1,1,2,3,3,4,5};   /* number of mp3 decoder instances */

  1919. /* offsets into output buffer, assume output order is FL FR BL BR C LFE */

  1920. static const uint8_t chan_offset[8][5] = {

  1921.     {0},

  1922.     {0},            // C

  1923.     {0},            // FLR

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

  1925.     {2,0,3},        // C FLR BS

  1926.     {4,0,2},        // C FLR BLRS

  1927.     {4,0,2,5},      // C FLR BLRS LFE

  1928.     {4,0,2,6,5},    // C FLR BLRS BLR LFE

  1929. };

  1930. 

  1931. 

  1932. static int decode_init_mp3on4(AVCodecContext * avctx)

  1933. {

  1934.     MP3On4DecodeContext *s = avctx->priv_data;

  1935.     MPEG4AudioConfig cfg;

  1936.     int i;

  1937. 

  1938.     if ((avctx->extradata_size < 2) || (avctx->extradata == NULL)) {

  1939.         av_log(avctx, AV_LOG_ERROR, "Codec extradata missing or too short.\n");

  1940.         return -1;

  1941.     }

  1942. 

  1943.     ff_mpeg4audio_get_config(&cfg, avctx->extradata, avctx->extradata_size);

  1944.     if (!cfg.chan_config || cfg.chan_config > 7) {

  1945.         av_log(avctx, AV_LOG_ERROR, "Invalid channel config number.\n");

  1946.         return -1;

  1947.     }

  1948.     s->frames = mp3Frames[cfg.chan_config];

  1949.     s->coff = chan_offset[cfg.chan_config];

  1950.     avctx->channels = ff_mpeg4audio_channels[cfg.chan_config];

  1951. 

  1952.     if (cfg.sample_rate < 16000)

  1953.         s->syncword = 0xffe00000;

  1954.     else

  1955.         s->syncword = 0xfff00000;

  1956. 

  1957.     /* Init the first mp3 decoder in standard way, so that all tables get builded

  1958.      * We replace avctx->priv_data with the context of the first decoder so that

  1959.      * decode_init() does not have to be changed.

  1960.      * Other decoders will be initialized here copying data from the first context

  1961.      */

  1962.     // Allocate zeroed memory for the first decoder context

  1963.     s->mp3decctx[0] = av_mallocz(sizeof(MPADecodeContext));

  1964.     // Put decoder context in place to make init_decode() happy

  1965.     avctx->priv_data = s->mp3decctx[0];

  1966.     decode_init(avctx);

  1967.     // Restore mp3on4 context pointer

  1968.     avctx->priv_data = s;

  1969.     s->mp3decctx[0]->adu_mode = 1; // Set adu mode

  1970. 

  1971.     /* Create a separate codec/context for each frame (first is already ok).

  1972.      * Each frame is 1 or 2 channels - up to 5 frames allowed

  1973.      */

  1974.     for (i = 1; i < s->frames; i++) {

  1975.         s->mp3decctx[i] = av_mallocz(sizeof(MPADecodeContext));

  1976.         s->mp3decctx[i]->adu_mode = 1;

  1977.         s->mp3decctx[i]->avctx = avctx;

  1978.     }

  1979. 

  1980.     return 0;

  1981. }

  1982. 

  1983. 

  1984. static av_cold int decode_close_mp3on4(AVCodecContext * avctx)

  1985. {

  1986.     MP3On4DecodeContext *s = avctx->priv_data;

  1987.     int i;

  1988. 

  1989.     for (i = 0; i < s->frames; i++)

  1990.         av_free(s->mp3decctx[i]);

  1991. 

  1992.     return 0;

  1993. }

  1994. 

  1995. 

  1996. static int decode_frame_mp3on4(AVCodecContext * avctx,

  1997.                         void *data, int *data_size,

  1998.                         AVPacket *avpkt)

  1999. {

  2000.     const uint8_t *buf = avpkt->data;

  2001.     int buf_size = avpkt->size;

  2002.     MP3On4DecodeContext *s = avctx->priv_data;

  2003.     MPADecodeContext *m;

  2004.     int fsize, len = buf_size, out_size = 0;

  2005.     uint32_t header;

  2006.     OUT_INT *out_samples = data;

  2007.     OUT_INT decoded_buf[MPA_FRAME_SIZE * MPA_MAX_CHANNELS];

  2008.     OUT_INT *outptr, *bp;

  2009.     int fr, j, n;

  2010. 

  2011.     if(*data_size < MPA_FRAME_SIZE * MPA_MAX_CHANNELS * s->frames * sizeof(OUT_INT))

  2012.         return -1;

  2013. 

  2014.     *data_size = 0;

  2015.     // Discard too short frames

  2016.     if (buf_size < HEADER_SIZE)

  2017.         return -1;

  2018. 

  2019.     // If only one decoder interleave is not needed

  2020.     outptr = s->frames == 1 ? out_samples : decoded_buf;

  2021. 

  2022.     avctx->bit_rate = 0;

  2023. 

  2024.     for (fr = 0; fr < s->frames; fr++) {

  2025.         fsize = AV_RB16(buf) >> 4;

  2026.         fsize = FFMIN3(fsize, len, MPA_MAX_CODED_FRAME_SIZE);

  2027.         m = s->mp3decctx[fr];

  2028.         assert (m != NULL);

  2029. 

  2030.         header = (AV_RB32(buf) & 0x000fffff) | s->syncword; // patch header

  2031. 

  2032.         if (ff_mpa_check_header(header) < 0) // Bad header, discard block

  2033.             break;

  2034. 

  2035.         ff_mpegaudio_decode_header((MPADecodeHeader *)m, header);

  2036.         out_size += mp_decode_frame(m, outptr, buf, fsize);

  2037.         buf += fsize;

  2038.         len -= fsize;

  2039. 

  2040.         if(s->frames > 1) {

  2041.             n = m->avctx->frame_size*m->nb_channels;

  2042.             /* interleave output data */

  2043.             bp = out_samples + s->coff[fr];

  2044.             if(m->nb_channels == 1) {

  2045.                 for(j = 0; j < n; j++) {

  2046.                     *bp = decoded_buf[j];

  2047.                     bp += avctx->channels;

  2048.                 }

  2049.             } else {

  2050.                 for(j = 0; j < n; j++) {

  2051.                     bp[0] = decoded_buf[j++];

  2052.                     bp[1] = decoded_buf[j];

  2053.                     bp += avctx->channels;

  2054.                 }

  2055.             }

  2056.         }

  2057.         avctx->bit_rate += m->bit_rate;

  2058.     }

  2059. 

  2060.     /* update codec info */

  2061.     avctx->sample_rate = s->mp3decctx[0]->sample_rate;

  2062. 

  2063.     *data_size = out_size;

  2064.     return buf_size;

  2065. }

  2066. #endif /* CONFIG_MP3ON4_DECODER || CONFIG_MP3ON4FLOAT_DECODER */

  2067. 

  2068. #if !CONFIG_FLOAT

  2069. #if CONFIG_MP1_DECODER

  2070. AVCodec ff_mp1_decoder =

  2071. {

  2072.     "mp1",

  2073.     AVMEDIA_TYPE_AUDIO,

  2074.     CODEC_ID_MP1,

  2075.     sizeof(MPADecodeContext),

  2076.     decode_init,

  2077.     NULL,

  2078.     NULL,

  2079.     decode_frame,

  2080.     CODEC_CAP_PARSE_ONLY,

  2081.     .flush= flush,

  2082.     .long_name= NULL_IF_CONFIG_SMALL("MP1 (MPEG audio layer 1)"),

  2083. };

  2084. #endif

  2085. #if CONFIG_MP2_DECODER

  2086. AVCodec ff_mp2_decoder =

  2087. {

  2088.     "mp2",

  2089.     AVMEDIA_TYPE_AUDIO,

  2090.     CODEC_ID_MP2,

  2091.     sizeof(MPADecodeContext),

  2092.     decode_init,

  2093.     NULL,

  2094.     NULL,

  2095.     decode_frame,

  2096.     CODEC_CAP_PARSE_ONLY,

  2097.     .flush= flush,

  2098.     .long_name= NULL_IF_CONFIG_SMALL("MP2 (MPEG audio layer 2)"),

  2099. };

  2100. #endif

  2101. #if CONFIG_MP3_DECODER

  2102. AVCodec ff_mp3_decoder =

  2103. {

  2104.     "mp3",

  2105.     AVMEDIA_TYPE_AUDIO,

  2106.     CODEC_ID_MP3,

  2107.     sizeof(MPADecodeContext),

  2108.     decode_init,

  2109.     NULL,

  2110.     NULL,

  2111.     decode_frame,

  2112.     CODEC_CAP_PARSE_ONLY,

  2113.     .flush= flush,

  2114.     .long_name= NULL_IF_CONFIG_SMALL("MP3 (MPEG audio layer 3)"),

  2115. };

  2116. #endif

  2117. #if CONFIG_MP3ADU_DECODER

  2118. AVCodec ff_mp3adu_decoder =

  2119. {

  2120.     "mp3adu",

  2121.     AVMEDIA_TYPE_AUDIO,

  2122.     CODEC_ID_MP3ADU,

  2123.     sizeof(MPADecodeContext),

  2124.     decode_init,

  2125.     NULL,

  2126.     NULL,

  2127.     decode_frame_adu,

  2128.     CODEC_CAP_PARSE_ONLY,

  2129.     .flush= flush,

  2130.     .long_name= NULL_IF_CONFIG_SMALL("ADU (Application Data Unit) MP3 (MPEG audio layer 3)"),

  2131. };

  2132. #endif

  2133. #if CONFIG_MP3ON4_DECODER

  2134. AVCodec ff_mp3on4_decoder =

  2135. {

  2136.     "mp3on4",

  2137.     AVMEDIA_TYPE_AUDIO,

  2138.     CODEC_ID_MP3ON4,

  2139.     sizeof(MP3On4DecodeContext),

  2140.     decode_init_mp3on4,

  2141.     NULL,

  2142.     decode_close_mp3on4,

  2143.     decode_frame_mp3on4,

  2144.     .flush= flush,

  2145.     .long_name= NULL_IF_CONFIG_SMALL("MP3onMP4"),

  2146. };

  2147. #endif

  2148. #endif