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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 mpegaudiodec.c

  24.  * MPEG Audio decoder.

  25.  */

  26. 

  27. //#define DEBUG

  28. #include "avcodec.h"

  29. #include "bitstream.h"

  30. #include "dsputil.h"

  31. 

  32. /*

  33.  * TODO:

  34.  *  - in low precision mode, use more 16 bit multiplies in synth filter

  35.  *  - test lsf / mpeg25 extensively.

  36.  */

  37. 

  38. /* define USE_HIGHPRECISION to have a bit exact (but slower) mpeg

  39.    audio decoder */

  40. #ifdef CONFIG_MPEGAUDIO_HP

  41. #   define USE_HIGHPRECISION

  42. #endif

  43. 

  44. #include "mpegaudio.h"

  45. #include "mpegaudiodecheader.h"

  46. 

  47. #include "mathops.h"

  48. 

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

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

  51. #define FRAC_RND(a) (((a) + (FRAC_ONE/2)) >> FRAC_BITS)

  52. 

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

  54. 

  55. /****************/

  56. 

  57. #define HEADER_SIZE 4

  58. 

  59. /**

  60.  * Context for MP3On4 decoder

  61.  */

  62. typedef struct MP3On4DecodeContext {

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

  64.     int chan_cfg; ///< channel config number

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

  66. } MP3On4DecodeContext;

  67. 

  68. /* layer 3 "granule" */

  69. typedef struct GranuleDef {

  70.     uint8_t scfsi;

  71.     int part2_3_length;

  72.     int big_values;

  73.     int global_gain;

  74.     int scalefac_compress;

  75.     uint8_t block_type;

  76.     uint8_t switch_point;

  77.     int table_select[3];

  78.     int subblock_gain[3];

  79.     uint8_t scalefac_scale;

  80.     uint8_t count1table_select;

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

  82.     int preflag;

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

  84.     uint8_t scale_factors[40];

  85.     int32_t sb_hybrid[SBLIMIT * 18]; /* 576 samples */

  86. } GranuleDef;

  87. 

  88. #define MODE_EXT_MS_STEREO 2

  89. #define MODE_EXT_I_STEREO  1

  90. 

  91. #include "mpegaudiodata.h"

  92. #include "mpegaudiodectab.h"

  93. 

  94. static void compute_antialias_integer(MPADecodeContext *s, GranuleDef *g);

  95. static void compute_antialias_float(MPADecodeContext *s, GranuleDef *g);

  96. 

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

  98. static VLC huff_vlc[16];

  99. static VLC huff_quad_vlc[2];

  100. /* computed from band_size_long */

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

  102. /* XXX: free when all decoders are closed */

  103. #define TABLE_4_3_SIZE (8191 + 16)*4

  104. static int8_t  table_4_3_exp[TABLE_4_3_SIZE];

  105. static uint32_t table_4_3_value[TABLE_4_3_SIZE];

  106. static uint32_t exp_table[512];

  107. static uint32_t expval_table[512][16];

  108. /* intensity stereo coef table */

  109. static int32_t is_table[2][16];

  110. static int32_t is_table_lsf[2][2][16];

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

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

  113. static int32_t mdct_win[8][36];

  114. 

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

  116. static uint16_t scale_factor_modshift[64];

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

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

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

  120. 

  121. #define SCALE_GEN(v) \

  122. { FIXR(1.0 * (v)), FIXR(0.7937005259 * (v)), FIXR(0.6299605249 * (v)) }

  123. 

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

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

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

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

  128. };

  129. 

  130. static DECLARE_ALIGNED_16(MPA_INT, window[512]);

  131. 

  132. /* layer 1 unscaling */

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

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

  135. {

  136.     int shift, mod;

  137.     int64_t val;

  138. 

  139.     shift = scale_factor_modshift[scale_factor];

  140.     mod = shift & 3;

  141.     shift >>= 2;

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

  143.     shift += n;

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

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

  146. }

  147. 

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

  149. {

  150.     int shift, mod, val;

  151. 

  152.     shift = scale_factor_modshift[scale_factor];

  153.     mod = shift & 3;

  154.     shift >>= 2;

  155. 

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

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

  158.     if (shift > 0)

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

  160.     return val;

  161. }

  162. 

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

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

  165. {

  166.     unsigned int m;

  167.     int e;

  168. 

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

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

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

  172.     assert(e>=1);

  173.     if (e > 31)

  174.         return 0;

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

  176. 

  177.     return m;

  178. }

  179. 

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

  181. #define DEV_ORDER 13

  182. 

  183. #define POW_FRAC_BITS 24

  184. #define POW_FRAC_ONE    (1 << POW_FRAC_BITS)

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

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

  187. 

  188. static int dev_4_3_coefs[DEV_ORDER];

  189. 

  190. #if 0 /* unused */

  191. static int pow_mult3[3] = {

  192.     POW_FIX(1.0),

  193.     POW_FIX(1.25992104989487316476),

  194.     POW_FIX(1.58740105196819947474),

  195. };

  196. #endif

  197. 

  198. static void int_pow_init(void)

  199. {

  200.     int i, a;

  201. 

  202.     a = POW_FIX(1.0);

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

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

  205.         dev_4_3_coefs[i] = a;

  206.     }

  207. }

  208. 

  209. #if 0 /* unused, remove? */

  210. /* return the mantissa and the binary exponent */

  211. static int int_pow(int i, int *exp_ptr)

  212. {

  213.     int e, er, eq, j;

  214.     int a, a1;

  215. 

  216.     /* renormalize */

  217.     a = i;

  218.     e = POW_FRAC_BITS;

  219.     while (a < (1 << (POW_FRAC_BITS - 1))) {

  220.         a = a << 1;

  221.         e--;

  222.     }

  223.     a -= (1 << POW_FRAC_BITS);

  224.     a1 = 0;

  225.     for(j = DEV_ORDER - 1; j >= 0; j--)

  226.         a1 = POW_MULL(a, dev_4_3_coefs[j] + a1);

  227.     a = (1 << POW_FRAC_BITS) + a1;

  228.     /* exponent compute (exact) */

  229.     e = e * 4;

  230.     er = e % 3;

  231.     eq = e / 3;

  232.     a = POW_MULL(a, pow_mult3[er]);

  233.     while (a >= 2 * POW_FRAC_ONE) {

  234.         a = a >> 1;

  235.         eq++;

  236.     }

  237.     /* convert to float */

  238.     while (a < POW_FRAC_ONE) {

  239.         a = a << 1;

  240.         eq--;

  241.     }

  242.     /* now POW_FRAC_ONE <= a < 2 * POW_FRAC_ONE */

  243. #if POW_FRAC_BITS > FRAC_BITS

  244.     a = (a + (1 << (POW_FRAC_BITS - FRAC_BITS - 1))) >> (POW_FRAC_BITS - FRAC_BITS);

  245.     /* correct overflow */

  246.     if (a >= 2 * (1 << FRAC_BITS)) {

  247.         a = a >> 1;

  248.         eq++;

  249.     }

  250. #endif

  251.     *exp_ptr = eq;

  252.     return a;

  253. }

  254. #endif

  255. 

  256. static int decode_init(AVCodecContext * avctx)

  257. {

  258.     MPADecodeContext *s = avctx->priv_data;

  259.     static int init=0;

  260.     int i, j, k;

  261. 

  262.     s->avctx = avctx;

  263. 

  264. #if defined(USE_HIGHPRECISION) && defined(CONFIG_AUDIO_NONSHORT)

  265.     avctx->sample_fmt= SAMPLE_FMT_S32;

  266. #else

  267.     avctx->sample_fmt= SAMPLE_FMT_S16;

  268. #endif

  269.     s->error_resilience= avctx->error_resilience;

  270. 

  271.     if(avctx->antialias_algo != FF_AA_FLOAT)

  272.         s->compute_antialias= compute_antialias_integer;

  273.     else

  274.         s->compute_antialias= compute_antialias_float;

  275. 

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

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

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

  279.             int shift, mod;

  280.             /* 1.0 (i = 3) is normalized to 2 ^ FRAC_BITS */

  281.             shift = (i / 3);

  282.             mod = i % 3;

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

  284.         }

  285. 

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

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

  288.             int n, norm;

  289.             n = i + 2;

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

  291.             scale_factor_mult[i][0] = MULL(FIXR(1.0 * 2.0), norm);

  292.             scale_factor_mult[i][1] = MULL(FIXR(0.7937005259 * 2.0), norm);

  293.             scale_factor_mult[i][2] = MULL(FIXR(0.6299605249 * 2.0), norm);

  294.             dprintf(avctx, "%d: norm=%x s=%x %x %x\n",

  295.                     i, norm,

  296.                     scale_factor_mult[i][0],

  297.                     scale_factor_mult[i][1],

  298.                     scale_factor_mult[i][2]);

  299.         }

  300. 

  301.         ff_mpa_synth_init(window);

  302. 

  303.         /* huffman decode tables */

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

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

  306.             int xsize, x, y;

  307.             unsigned int n;

  308.             uint8_t  tmp_bits [512];

  309.             uint16_t tmp_codes[512];

  310. 

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

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

  313. 

  314.             xsize = h->xsize;

  315.             n = xsize * xsize;

  316. 

  317.             j = 0;

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

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

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

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

  322.                 }

  323.             }

  324. 

  325.             /* XXX: fail test */

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

  327.                      tmp_bits, 1, 1, tmp_codes, 2, 2, 1);

  328.         }

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

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

  331.                      mpa_quad_bits[i], 1, 1, mpa_quad_codes[i], 1, 1, 1);

  332.         }

  333. 

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

  335.             k = 0;

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

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

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

  339.             }

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

  341.         }

  342. 

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

  344. 

  345.         int_pow_init();

  346.         for(i=1;i<TABLE_4_3_SIZE;i++) {

  347.             double f, fm;

  348.             int e, m;

  349.             f = pow((double)(i/4), 4.0 / 3.0) * pow(2, (i&3)*0.25);

  350.             fm = frexp(f, &e);

  351.             m = (uint32_t)(fm*(1LL<<31) + 0.5);

  352.             e+= FRAC_BITS - 31 + 5 - 100;

  353. 

  354.             /* normalized to FRAC_BITS */

  355.             table_4_3_value[i] = m;

  356. //            av_log(NULL, AV_LOG_DEBUG, "%d %d %f\n", i, m, pow((double)i, 4.0 / 3.0));

  357.             table_4_3_exp[i] = -e;

  358.         }

  359.         for(i=0; i<512*16; i++){

  360.             int exponent= (i>>4);

  361.             double f= pow(i&15, 4.0 / 3.0) * pow(2, (exponent-400)*0.25 + FRAC_BITS + 5);

  362.             expval_table[exponent][i&15]= llrint(f);

  363.             if((i&15)==1)

  364.                 exp_table[exponent]= llrint(f);

  365.         }

  366. 

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

  368.             float f;

  369.             int v;

  370.             if (i != 6) {

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

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

  373.             } else {

  374.                 v = FIXR(1.0);

  375.             }

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

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

  378.         }

  379.         /* invalid values */

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

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

  382. 

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

  384.             double f;

  385.             int e, k;

  386. 

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

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

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

  390.                 k = i & 1;

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

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

  393.                 dprintf(avctx, "is_table_lsf %d %d: %x %x\n",

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

  395.             }

  396.         }

  397. 

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

  399.             float ci, cs, ca;

  400.             ci = ci_table[i];

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

  402.             ca = cs * ci;

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

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

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

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

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

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

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

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

  411. //            printf("%d %d %d %d\n", FIX(cs), FIX(cs-1), FIX(ca), FIX(cs)-FIX(ca));

  412. //            av_log(NULL, AV_LOG_DEBUG,"%f %f %f %f\n", cs, ca, ca+cs, ca-cs);

  413.         }

  414. 

  415.         /* compute mdct windows */

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

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

  418.                 double d;

  419. 

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

  421.                     continue;

  422. 

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

  424.                 if(j==1){

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

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

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

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

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

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

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

  432.                 }

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

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

  435. 

  436.                 if(j==2)

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

  438.                 else

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

  440. //                av_log(NULL, AV_LOG_DEBUG, "%2d %d %f\n", i,j,d / (1<<5));

  441.             }

  442.         }

  443. 

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

  445.            the sign of the right window coefs */

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

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

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

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

  450.             }

  451.         }

  452. 

  453. #if defined(DEBUG)

  454.         for(j=0;j<8;j++) {

  455.             av_log(avctx, AV_LOG_DEBUG, "win%d=\n", j);

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

  457.                 av_log(avctx, AV_LOG_DEBUG, "%f, ", (double)mdct_win[j][i] / FRAC_ONE);

  458.             av_log(avctx, AV_LOG_DEBUG, "\n");

  459.         }

  460. #endif

  461.         init = 1;

  462.     }

  463. 

  464. #ifdef DEBUG

  465.     s->frame_count = 0;

  466. #endif

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

  468.         s->adu_mode = 1;

  469.     return 0;

  470. }

  471. 

  472. /* tab[i][j] = 1.0 / (2.0 * cos(pi*(2*k+1) / 2^(6 - j))) */

  473. 

  474. /* cos(i*pi/64) */

  475. 

  476. #define COS0_0  FIXHR(0.50060299823519630134/2)

  477. #define COS0_1  FIXHR(0.50547095989754365998/2)

  478. #define COS0_2  FIXHR(0.51544730992262454697/2)

  479. #define COS0_3  FIXHR(0.53104259108978417447/2)

  480. #define COS0_4  FIXHR(0.55310389603444452782/2)

  481. #define COS0_5  FIXHR(0.58293496820613387367/2)

  482. #define COS0_6  FIXHR(0.62250412303566481615/2)

  483. #define COS0_7  FIXHR(0.67480834145500574602/2)

  484. #define COS0_8  FIXHR(0.74453627100229844977/2)

  485. #define COS0_9  FIXHR(0.83934964541552703873/2)

  486. #define COS0_10 FIXHR(0.97256823786196069369/2)

  487. #define COS0_11 FIXHR(1.16943993343288495515/4)

  488. #define COS0_12 FIXHR(1.48416461631416627724/4)

  489. #define COS0_13 FIXHR(2.05778100995341155085/8)

  490. #define COS0_14 FIXHR(3.40760841846871878570/8)

  491. #define COS0_15 FIXHR(10.19000812354805681150/32)

  492. 

  493. #define COS1_0 FIXHR(0.50241928618815570551/2)

  494. #define COS1_1 FIXHR(0.52249861493968888062/2)

  495. #define COS1_2 FIXHR(0.56694403481635770368/2)

  496. #define COS1_3 FIXHR(0.64682178335999012954/2)

  497. #define COS1_4 FIXHR(0.78815462345125022473/2)

  498. #define COS1_5 FIXHR(1.06067768599034747134/4)

  499. #define COS1_6 FIXHR(1.72244709823833392782/4)

  500. #define COS1_7 FIXHR(5.10114861868916385802/16)

  501. 

  502. #define COS2_0 FIXHR(0.50979557910415916894/2)

  503. #define COS2_1 FIXHR(0.60134488693504528054/2)

  504. #define COS2_2 FIXHR(0.89997622313641570463/2)

  505. #define COS2_3 FIXHR(2.56291544774150617881/8)

  506. 

  507. #define COS3_0 FIXHR(0.54119610014619698439/2)

  508. #define COS3_1 FIXHR(1.30656296487637652785/4)

  509. 

  510. #define COS4_0 FIXHR(0.70710678118654752439/2)

  511. 

  512. /* butterfly operator */

  513. #define BF(a, b, c, s)\

  514. {\

  515.     tmp0 = tab[a] + tab[b];\

  516.     tmp1 = tab[a] - tab[b];\

  517.     tab[a] = tmp0;\

  518.     tab[b] = MULH(tmp1<<(s), c);\

  519. }

  520. 

  521. #define BF1(a, b, c, d)\

  522. {\

  523.     BF(a, b, COS4_0, 1);\

  524.     BF(c, d,-COS4_0, 1);\

  525.     tab[c] += tab[d];\

  526. }

  527. 

  528. #define BF2(a, b, c, d)\

  529. {\

  530.     BF(a, b, COS4_0, 1);\

  531.     BF(c, d,-COS4_0, 1);\

  532.     tab[c] += tab[d];\

  533.     tab[a] += tab[c];\

  534.     tab[c] += tab[b];\

  535.     tab[b] += tab[d];\

  536. }

  537. 

  538. #define ADD(a, b) tab[a] += tab[b]

  539. 

  540. /* DCT32 without 1/sqrt(2) coef zero scaling. */

  541. static void dct32(int32_t *out, int32_t *tab)

  542. {

  543.     int tmp0, tmp1;

  544. 

  545.     /* pass 1 */

  546.     BF( 0, 31, COS0_0 , 1);

  547.     BF(15, 16, COS0_15, 5);

  548.     /* pass 2 */

  549.     BF( 0, 15, COS1_0 , 1);

  550.     BF(16, 31,-COS1_0 , 1);

  551.     /* pass 1 */

  552.     BF( 7, 24, COS0_7 , 1);

  553.     BF( 8, 23, COS0_8 , 1);

  554.     /* pass 2 */

  555.     BF( 7,  8, COS1_7 , 4);

  556.     BF(23, 24,-COS1_7 , 4);

  557.     /* pass 3 */

  558.     BF( 0,  7, COS2_0 , 1);

  559.     BF( 8, 15,-COS2_0 , 1);

  560.     BF(16, 23, COS2_0 , 1);

  561.     BF(24, 31,-COS2_0 , 1);

  562.     /* pass 1 */

  563.     BF( 3, 28, COS0_3 , 1);

  564.     BF(12, 19, COS0_12, 2);

  565.     /* pass 2 */

  566.     BF( 3, 12, COS1_3 , 1);

  567.     BF(19, 28,-COS1_3 , 1);

  568.     /* pass 1 */

  569.     BF( 4, 27, COS0_4 , 1);

  570.     BF(11, 20, COS0_11, 2);

  571.     /* pass 2 */

  572.     BF( 4, 11, COS1_4 , 1);

  573.     BF(20, 27,-COS1_4 , 1);

  574.     /* pass 3 */

  575.     BF( 3,  4, COS2_3 , 3);

  576.     BF(11, 12,-COS2_3 , 3);

  577.     BF(19, 20, COS2_3 , 3);

  578.     BF(27, 28,-COS2_3 , 3);

  579.     /* pass 4 */

  580.     BF( 0,  3, COS3_0 , 1);

  581.     BF( 4,  7,-COS3_0 , 1);

  582.     BF( 8, 11, COS3_0 , 1);

  583.     BF(12, 15,-COS3_0 , 1);

  584.     BF(16, 19, COS3_0 , 1);

  585.     BF(20, 23,-COS3_0 , 1);

  586.     BF(24, 27, COS3_0 , 1);

  587.     BF(28, 31,-COS3_0 , 1);

  588. 

  589. 

  590. 

  591.     /* pass 1 */

  592.     BF( 1, 30, COS0_1 , 1);

  593.     BF(14, 17, COS0_14, 3);

  594.     /* pass 2 */

  595.     BF( 1, 14, COS1_1 , 1);

  596.     BF(17, 30,-COS1_1 , 1);

  597.     /* pass 1 */

  598.     BF( 6, 25, COS0_6 , 1);

  599.     BF( 9, 22, COS0_9 , 1);

  600.     /* pass 2 */

  601.     BF( 6,  9, COS1_6 , 2);

  602.     BF(22, 25,-COS1_6 , 2);

  603.     /* pass 3 */

  604.     BF( 1,  6, COS2_1 , 1);

  605.     BF( 9, 14,-COS2_1 , 1);

  606.     BF(17, 22, COS2_1 , 1);

  607.     BF(25, 30,-COS2_1 , 1);

  608. 

  609.     /* pass 1 */

  610.     BF( 2, 29, COS0_2 , 1);

  611.     BF(13, 18, COS0_13, 3);

  612.     /* pass 2 */

  613.     BF( 2, 13, COS1_2 , 1);

  614.     BF(18, 29,-COS1_2 , 1);

  615.     /* pass 1 */

  616.     BF( 5, 26, COS0_5 , 1);

  617.     BF(10, 21, COS0_10, 1);

  618.     /* pass 2 */

  619.     BF( 5, 10, COS1_5 , 2);

  620.     BF(21, 26,-COS1_5 , 2);

  621.     /* pass 3 */

  622.     BF( 2,  5, COS2_2 , 1);

  623.     BF(10, 13,-COS2_2 , 1);

  624.     BF(18, 21, COS2_2 , 1);

  625.     BF(26, 29,-COS2_2 , 1);

  626.     /* pass 4 */

  627.     BF( 1,  2, COS3_1 , 2);

  628.     BF( 5,  6,-COS3_1 , 2);

  629.     BF( 9, 10, COS3_1 , 2);

  630.     BF(13, 14,-COS3_1 , 2);

  631.     BF(17, 18, COS3_1 , 2);

  632.     BF(21, 22,-COS3_1 , 2);

  633.     BF(25, 26, COS3_1 , 2);

  634.     BF(29, 30,-COS3_1 , 2);

  635. 

  636.     /* pass 5 */

  637.     BF1( 0,  1,  2,  3);

  638.     BF2( 4,  5,  6,  7);

  639.     BF1( 8,  9, 10, 11);

  640.     BF2(12, 13, 14, 15);

  641.     BF1(16, 17, 18, 19);

  642.     BF2(20, 21, 22, 23);

  643.     BF1(24, 25, 26, 27);

  644.     BF2(28, 29, 30, 31);

  645. 

  646.     /* pass 6 */

  647. 

  648.     ADD( 8, 12);

  649.     ADD(12, 10);

  650.     ADD(10, 14);

  651.     ADD(14,  9);

  652.     ADD( 9, 13);

  653.     ADD(13, 11);

  654.     ADD(11, 15);

  655. 

  656.     out[ 0] = tab[0];

  657.     out[16] = tab[1];

  658.     out[ 8] = tab[2];

  659.     out[24] = tab[3];

  660.     out[ 4] = tab[4];

  661.     out[20] = tab[5];

  662.     out[12] = tab[6];

  663.     out[28] = tab[7];

  664.     out[ 2] = tab[8];

  665.     out[18] = tab[9];

  666.     out[10] = tab[10];

  667.     out[26] = tab[11];

  668.     out[ 6] = tab[12];

  669.     out[22] = tab[13];

  670.     out[14] = tab[14];

  671.     out[30] = tab[15];

  672. 

  673.     ADD(24, 28);

  674.     ADD(28, 26);

  675.     ADD(26, 30);

  676.     ADD(30, 25);

  677.     ADD(25, 29);

  678.     ADD(29, 27);

  679.     ADD(27, 31);

  680. 

  681.     out[ 1] = tab[16] + tab[24];

  682.     out[17] = tab[17] + tab[25];

  683.     out[ 9] = tab[18] + tab[26];

  684.     out[25] = tab[19] + tab[27];

  685.     out[ 5] = tab[20] + tab[28];

  686.     out[21] = tab[21] + tab[29];

  687.     out[13] = tab[22] + tab[30];

  688.     out[29] = tab[23] + tab[31];

  689.     out[ 3] = tab[24] + tab[20];

  690.     out[19] = tab[25] + tab[21];

  691.     out[11] = tab[26] + tab[22];

  692.     out[27] = tab[27] + tab[23];

  693.     out[ 7] = tab[28] + tab[18];

  694.     out[23] = tab[29] + tab[19];

  695.     out[15] = tab[30] + tab[17];

  696.     out[31] = tab[31];

  697. }

  698. 

  699. #if FRAC_BITS <= 15

  700. 

  701. static inline int round_sample(int *sum)

  702. {

  703.     int sum1;

  704.     sum1 = (*sum) >> OUT_SHIFT;

  705.     *sum &= (1<<OUT_SHIFT)-1;

  706.     if (sum1 < OUT_MIN)

  707.         sum1 = OUT_MIN;

  708.     else if (sum1 > OUT_MAX)

  709.         sum1 = OUT_MAX;

  710.     return sum1;

  711. }

  712. 

  713. /* signed 16x16 -> 32 multiply add accumulate */

  714. #define MACS(rt, ra, rb) MAC16(rt, ra, rb)

  715. 

  716. /* signed 16x16 -> 32 multiply */

  717. #define MULS(ra, rb) MUL16(ra, rb)

  718. 

  719. #else

  720. 

  721. static inline int round_sample(int64_t *sum)

  722. {

  723.     int sum1;

  724.     sum1 = (int)((*sum) >> OUT_SHIFT);

  725.     *sum &= (1<<OUT_SHIFT)-1;

  726.     if (sum1 < OUT_MIN)

  727.         sum1 = OUT_MIN;

  728.     else if (sum1 > OUT_MAX)

  729.         sum1 = OUT_MAX;

  730.     return sum1;

  731. }

  732. 

  733. #   define MULS(ra, rb) MUL64(ra, rb)

  734. #endif

  735. 

  736. #define SUM8(sum, op, w, p) \

  737. {                                               \

  738.     sum op MULS((w)[0 * 64], p[0 * 64]);\

  739.     sum op MULS((w)[1 * 64], p[1 * 64]);\

  740.     sum op MULS((w)[2 * 64], p[2 * 64]);\

  741.     sum op MULS((w)[3 * 64], p[3 * 64]);\

  742.     sum op MULS((w)[4 * 64], p[4 * 64]);\

  743.     sum op MULS((w)[5 * 64], p[5 * 64]);\

  744.     sum op MULS((w)[6 * 64], p[6 * 64]);\

  745.     sum op MULS((w)[7 * 64], p[7 * 64]);\

  746. }

  747. 

  748. #define SUM8P2(sum1, op1, sum2, op2, w1, w2, p) \

  749. {                                               \

  750.     int tmp;\

  751.     tmp = p[0 * 64];\

  752.     sum1 op1 MULS((w1)[0 * 64], tmp);\

  753.     sum2 op2 MULS((w2)[0 * 64], tmp);\

  754.     tmp = p[1 * 64];\

  755.     sum1 op1 MULS((w1)[1 * 64], tmp);\

  756.     sum2 op2 MULS((w2)[1 * 64], tmp);\

  757.     tmp = p[2 * 64];\

  758.     sum1 op1 MULS((w1)[2 * 64], tmp);\

  759.     sum2 op2 MULS((w2)[2 * 64], tmp);\

  760.     tmp = p[3 * 64];\

  761.     sum1 op1 MULS((w1)[3 * 64], tmp);\

  762.     sum2 op2 MULS((w2)[3 * 64], tmp);\

  763.     tmp = p[4 * 64];\

  764.     sum1 op1 MULS((w1)[4 * 64], tmp);\

  765.     sum2 op2 MULS((w2)[4 * 64], tmp);\

  766.     tmp = p[5 * 64];\

  767.     sum1 op1 MULS((w1)[5 * 64], tmp);\

  768.     sum2 op2 MULS((w2)[5 * 64], tmp);\

  769.     tmp = p[6 * 64];\

  770.     sum1 op1 MULS((w1)[6 * 64], tmp);\

  771.     sum2 op2 MULS((w2)[6 * 64], tmp);\

  772.     tmp = p[7 * 64];\

  773.     sum1 op1 MULS((w1)[7 * 64], tmp);\

  774.     sum2 op2 MULS((w2)[7 * 64], tmp);\

  775. }

  776. 

  777. void ff_mpa_synth_init(MPA_INT *window)

  778. {

  779.     int i;

  780. 

  781.     /* max = 18760, max sum over all 16 coefs : 44736 */

  782.     for(i=0;i<257;i++) {

  783.         int v;

  784.         v = ff_mpa_enwindow[i];

  785. #if WFRAC_BITS < 16

  786.         v = (v + (1 << (16 - WFRAC_BITS - 1))) >> (16 - WFRAC_BITS);

  787. #endif

  788.         window[i] = v;

  789.         if ((i & 63) != 0)

  790.             v = -v;

  791.         if (i != 0)

  792.             window[512 - i] = v;

  793.     }

  794. }

  795. 

  796. /* 32 sub band synthesis filter. Input: 32 sub band samples, Output:

  797.    32 samples. */

  798. /* XXX: optimize by avoiding ring buffer usage */

  799. void ff_mpa_synth_filter(MPA_INT *synth_buf_ptr, int *synth_buf_offset,

  800.                          MPA_INT *window, int *dither_state,

  801.                          OUT_INT *samples, int incr,

  802.                          int32_t sb_samples[SBLIMIT])

  803. {

  804.     int32_t tmp[32];

  805.     register MPA_INT *synth_buf;

  806.     register const MPA_INT *w, *w2, *p;

  807.     int j, offset, v;

  808.     OUT_INT *samples2;

  809. #if FRAC_BITS <= 15

  810.     int sum, sum2;

  811. #else

  812.     int64_t sum, sum2;

  813. #endif

  814. 

  815.     dct32(tmp, sb_samples);

  816. 

  817.     offset = *synth_buf_offset;

  818.     synth_buf = synth_buf_ptr + offset;

  819. 

  820.     for(j=0;j<32;j++) {

  821.         v = tmp[j];

  822. #if FRAC_BITS <= 15

  823.         /* NOTE: can cause a loss in precision if very high amplitude

  824.            sound */

  825.         if (v > 32767)

  826.             v = 32767;

  827.         else if (v < -32768)

  828.             v = -32768;

  829. #endif

  830.         synth_buf[j] = v;

  831.     }

  832.     /* copy to avoid wrap */

  833.     memcpy(synth_buf + 512, synth_buf, 32 * sizeof(MPA_INT));

  834. 

  835.     samples2 = samples + 31 * incr;

  836.     w = window;

  837.     w2 = window + 31;

  838. 

  839.     sum = *dither_state;

  840.     p = synth_buf + 16;

  841.     SUM8(sum, +=, w, p);

  842.     p = synth_buf + 48;

  843.     SUM8(sum, -=, w + 32, p);

  844.     *samples = round_sample(&sum);

  845.     samples += incr;

  846.     w++;

  847. 

  848.     /* we calculate two samples at the same time to avoid one memory

  849.        access per two sample */

  850.     for(j=1;j<16;j++) {

  851.         sum2 = 0;

  852.         p = synth_buf + 16 + j;

  853.         SUM8P2(sum, +=, sum2, -=, w, w2, p);

  854.         p = synth_buf + 48 - j;

  855.         SUM8P2(sum, -=, sum2, -=, w + 32, w2 + 32, p);

  856. 

  857.         *samples = round_sample(&sum);

  858.         samples += incr;

  859.         sum += sum2;

  860.         *samples2 = round_sample(&sum);

  861.         samples2 -= incr;

  862.         w++;

  863.         w2--;

  864.     }

  865. 

  866.     p = synth_buf + 32;

  867.     SUM8(sum, -=, w + 32, p);

  868.     *samples = round_sample(&sum);

  869.     *dither_state= sum;

  870. 

  871.     offset = (offset - 32) & 511;

  872.     *synth_buf_offset = offset;

  873. }

  874. 

  875. #define C3 FIXHR(0.86602540378443864676/2)

  876. 

  877. /* 0.5 / cos(pi*(2*i+1)/36) */

  878. static const int icos36[9] = {

  879.     FIXR(0.50190991877167369479),

  880.     FIXR(0.51763809020504152469), //0

  881.     FIXR(0.55168895948124587824),

  882.     FIXR(0.61038729438072803416),

  883.     FIXR(0.70710678118654752439), //1

  884.     FIXR(0.87172339781054900991),

  885.     FIXR(1.18310079157624925896),

  886.     FIXR(1.93185165257813657349), //2

  887.     FIXR(5.73685662283492756461),

  888. };

  889. 

  890. /* 0.5 / cos(pi*(2*i+1)/36) */

  891. static const int icos36h[9] = {

  892.     FIXHR(0.50190991877167369479/2),

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

  894.     FIXHR(0.55168895948124587824/2),

  895.     FIXHR(0.61038729438072803416/2),

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

  897.     FIXHR(0.87172339781054900991/2),

  898.     FIXHR(1.18310079157624925896/4),

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

  900. //    FIXHR(5.73685662283492756461),

  901. };

  902. 

  903. /* 12 points IMDCT. We compute it "by hand" by factorizing obvious

  904.    cases. */

  905. static void imdct12(int *out, int *in)

  906. {

  907.     int in0, in1, in2, in3, in4, in5, t1, t2;

  908. 

  909.     in0= in[0*3];

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

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

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

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

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

  915.     in5 += in3;

  916.     in3 += in1;

  917. 

  918.     in2= MULH(2*in2, C3);

  919.     in3= MULH(4*in3, C3);

  920. 

  921.     t1 = in0 - in4;

  922.     t2 = MULH(2*(in1 - in5), icos36h[4]);

  923. 

  924.     out[ 7]=

  925.     out[10]= t1 + t2;

  926.     out[ 1]=

  927.     out[ 4]= t1 - t2;

  928. 

  929.     in0 += in4>>1;

  930.     in4 = in0 + in2;

  931.     in5 += 2*in1;

  932.     in1 = MULH(in5 + in3, icos36h[1]);

  933.     out[ 8]=

  934.     out[ 9]= in4 + in1;

  935.     out[ 2]=

  936.     out[ 3]= in4 - in1;

  937. 

  938.     in0 -= in2;

  939.     in5 = MULH(2*(in5 - in3), icos36h[7]);

  940.     out[ 0]=

  941.     out[ 5]= in0 - in5;

  942.     out[ 6]=

  943.     out[11]= in0 + in5;

  944. }

  945. 

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

  947. #define C1 FIXHR(0.98480775301220805936/2)

  948. #define C2 FIXHR(0.93969262078590838405/2)

  949. #define C3 FIXHR(0.86602540378443864676/2)

  950. #define C4 FIXHR(0.76604444311897803520/2)

  951. #define C5 FIXHR(0.64278760968653932632/2)

  952. #define C6 FIXHR(0.5/2)

  953. #define C7 FIXHR(0.34202014332566873304/2)

  954. #define C8 FIXHR(0.17364817766693034885/2)

  955. 

  956. 

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

  958. static void imdct36(int *out, int *buf, int *in, int *win)

  959. {

  960.     int i, j, t0, t1, t2, t3, s0, s1, s2, s3;

  961.     int tmp[18], *tmp1, *in1;

  962. 

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

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

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

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

  967. 

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

  969.         tmp1 = tmp + j;

  970.         in1 = in + j;

  971. #if 0

  972. //more accurate but slower

  973.         int64_t t0, t1, t2, t3;

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

  975. 

  976.         t3 = (in1[2*0] + (int64_t)(in1[2*6]>>1))<<32;

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

  978.         tmp1[ 6] = t1 - (t2>>1);

  979.         tmp1[16] = t1 + t2;

  980. 

  981.         t0 = MUL64(2*(in1[2*2] + in1[2*4]),    C2);

  982.         t1 = MUL64(   in1[2*4] - in1[2*8] , -2*C8);

  983.         t2 = MUL64(2*(in1[2*2] + in1[2*8]),   -C4);

  984. 

  985.         tmp1[10] = (t3 - t0 - t2) >> 32;

  986.         tmp1[ 2] = (t3 + t0 + t1) >> 32;

  987.         tmp1[14] = (t3 + t2 - t1) >> 32;

  988. 

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

  990.         t2 = MUL64(2*(in1[2*1] + in1[2*5]),    C1);

  991.         t3 = MUL64(   in1[2*5] - in1[2*7] , -2*C7);

  992.         t0 = MUL64(2*in1[2*3], C3);

  993. 

  994.         t1 = MUL64(2*(in1[2*1] + in1[2*7]),   -C5);

  995. 

  996.         tmp1[ 0] = (t2 + t3 + t0) >> 32;

  997.         tmp1[12] = (t2 + t1 - t0) >> 32;

  998.         tmp1[ 8] = (t3 - t1 - t0) >> 32;

  999. #else

  1000.         t2 = in1[2*4] + in1[2*8] - in1[2*2];

  1001. 

  1002.         t3 = in1[2*0] + (in1[2*6]>>1);

  1003.         t1 = in1[2*0] - in1[2*6];

  1004.         tmp1[ 6] = t1 - (t2>>1);

  1005.         tmp1[16] = t1 + t2;

  1006. 

  1007.         t0 = MULH(2*(in1[2*2] + in1[2*4]),    C2);

  1008.         t1 = MULH(   in1[2*4] - in1[2*8] , -2*C8);

  1009.         t2 = MULH(2*(in1[2*2] + in1[2*8]),   -C4);

  1010. 

  1011.         tmp1[10] = t3 - t0 - t2;

  1012.         tmp1[ 2] = t3 + t0 + t1;

  1013.         tmp1[14] = t3 + t2 - t1;

  1014. 

  1015.         tmp1[ 4] = MULH(2*(in1[2*5] + in1[2*7] - in1[2*1]), -C3);

  1016.         t2 = MULH(2*(in1[2*1] + in1[2*5]),    C1);

  1017.         t3 = MULH(   in1[2*5] - in1[2*7] , -2*C7);

  1018.         t0 = MULH(2*in1[2*3], C3);

  1019. 

  1020.         t1 = MULH(2*(in1[2*1] + in1[2*7]),   -C5);

  1021. 

  1022.         tmp1[ 0] = t2 + t3 + t0;

  1023.         tmp1[12] = t2 + t1 - t0;

  1024.         tmp1[ 8] = t3 - t1 - t0;

  1025. #endif

  1026.     }

  1027. 

  1028.     i = 0;

  1029.     for(j=0;j<4;j++) {

  1030.         t0 = tmp[i];

  1031.         t1 = tmp[i + 2];

  1032.         s0 = t1 + t0;

  1033.         s2 = t1 - t0;

  1034. 

  1035.         t2 = tmp[i + 1];

  1036.         t3 = tmp[i + 3];

  1037.         s1 = MULH(2*(t3 + t2), icos36h[j]);

  1038.         s3 = MULL(t3 - t2, icos36[8 - j]);

  1039. 

  1040.         t0 = s0 + s1;

  1041.         t1 = s0 - s1;

  1042.         out[(9 + j)*SBLIMIT] =  MULH(t1, win[9 + j]) + buf[9 + j];

  1043.         out[(8 - j)*SBLIMIT] =  MULH(t1, win[8 - j]) + buf[8 - j];

  1044.         buf[9 + j] = MULH(t0, win[18 + 9 + j]);

  1045.         buf[8 - j] = MULH(t0, win[18 + 8 - j]);

  1046. 

  1047.         t0 = s2 + s3;

  1048.         t1 = s2 - s3;

  1049.         out[(9 + 8 - j)*SBLIMIT] =  MULH(t1, win[9 + 8 - j]) + buf[9 + 8 - j];

  1050.         out[(        j)*SBLIMIT] =  MULH(t1, win[        j]) + buf[        j];

  1051.         buf[9 + 8 - j] = MULH(t0, win[18 + 9 + 8 - j]);

  1052.         buf[      + j] = MULH(t0, win[18         + j]);

  1053.         i += 4;

  1054.     }

  1055. 

  1056.     s0 = tmp[16];

  1057.     s1 = MULH(2*tmp[17], icos36h[4]);

  1058.     t0 = s0 + s1;

  1059.     t1 = s0 - s1;

  1060.     out[(9 + 4)*SBLIMIT] =  MULH(t1, win[9 + 4]) + buf[9 + 4];

  1061.     out[(8 - 4)*SBLIMIT] =  MULH(t1, win[8 - 4]) + buf[8 - 4];

  1062.     buf[9 + 4] = MULH(t0, win[18 + 9 + 4]);

  1063.     buf[8 - 4] = MULH(t0, win[18 + 8 - 4]);

  1064. }

  1065. 

  1066. /* return the number of decoded frames */

  1067. static int mp_decode_layer1(MPADecodeContext *s)

  1068. {

  1069.     int bound, i, v, n, ch, j, mant;

  1070.     uint8_t allocation[MPA_MAX_CHANNELS][SBLIMIT];

  1071.     uint8_t scale_factors[MPA_MAX_CHANNELS][SBLIMIT];

  1072. 

  1073.     if (s->mode == MPA_JSTEREO)

  1074.         bound = (s->mode_ext + 1) * 4;

  1075.     else

  1076.         bound = SBLIMIT;

  1077. 

  1078.     /* allocation bits */

  1079.     for(i=0;i<bound;i++) {

  1080.         for(ch=0;ch<s->nb_channels;ch++) {

  1081.             allocation[ch][i] = get_bits(&s->gb, 4);

  1082.         }

  1083.     }

  1084.     for(i=bound;i<SBLIMIT;i++) {

  1085.         allocation[0][i] = get_bits(&s->gb, 4);

  1086.     }

  1087. 

  1088.     /* scale factors */

  1089.     for(i=0;i<bound;i++) {

  1090.         for(ch=0;ch<s->nb_channels;ch++) {

  1091.             if (allocation[ch][i])

  1092.                 scale_factors[ch][i] = get_bits(&s->gb, 6);

  1093.         }

  1094.     }

  1095.     for(i=bound;i<SBLIMIT;i++) {

  1096.         if (allocation[0][i]) {

  1097.             scale_factors[0][i] = get_bits(&s->gb, 6);

  1098.             scale_factors[1][i] = get_bits(&s->gb, 6);

  1099.         }

  1100.     }

  1101. 

  1102.     /* compute samples */

  1103.     for(j=0;j<12;j++) {

  1104.         for(i=0;i<bound;i++) {

  1105.             for(ch=0;ch<s->nb_channels;ch++) {

  1106.                 n = allocation[ch][i];

  1107.                 if (n) {

  1108.                     mant = get_bits(&s->gb, n + 1);

  1109.                     v = l1_unscale(n, mant, scale_factors[ch][i]);

  1110.                 } else {

  1111.                     v = 0;

  1112.                 }

  1113.                 s->sb_samples[ch][j][i] = v;

  1114.             }

  1115.         }

  1116.         for(i=bound;i<SBLIMIT;i++) {

  1117.             n = allocation[0][i];

  1118.             if (n) {

  1119.                 mant = get_bits(&s->gb, n + 1);

  1120.                 v = l1_unscale(n, mant, scale_factors[0][i]);

  1121.                 s->sb_samples[0][j][i] = v;

  1122.                 v = l1_unscale(n, mant, scale_factors[1][i]);

  1123.                 s->sb_samples[1][j][i] = v;

  1124.             } else {

  1125.                 s->sb_samples[0][j][i] = 0;

  1126.                 s->sb_samples[1][j][i] = 0;

  1127.             }

  1128.         }

  1129.     }

  1130.     return 12;

  1131. }

  1132. 

  1133. static int mp_decode_layer2(MPADecodeContext *s)

  1134. {

  1135.     int sblimit; /* number of used subbands */

  1136.     const unsigned char *alloc_table;

  1137.     int table, bit_alloc_bits, i, j, ch, bound, v;

  1138.     unsigned char bit_alloc[MPA_MAX_CHANNELS][SBLIMIT];

  1139.     unsigned char scale_code[MPA_MAX_CHANNELS][SBLIMIT];

  1140.     unsigned char scale_factors[MPA_MAX_CHANNELS][SBLIMIT][3], *sf;

  1141.     int scale, qindex, bits, steps, k, l, m, b;

  1142. 

  1143.     /* select decoding table */

  1144.     table = ff_mpa_l2_select_table(s->bit_rate / 1000, s->nb_channels,

  1145.                             s->sample_rate, s->lsf);

  1146.     sblimit = ff_mpa_sblimit_table[table];

  1147.     alloc_table = ff_mpa_alloc_tables[table];

  1148. 

  1149.     if (s->mode == MPA_JSTEREO)

  1150.         bound = (s->mode_ext + 1) * 4;

  1151.     else

  1152.         bound = sblimit;

  1153. 

  1154.     dprintf(s->avctx, "bound=%d sblimit=%d\n", bound, sblimit);

  1155. 

  1156.     /* sanity check */

  1157.     if( bound > sblimit ) bound = sblimit;

  1158. 

  1159.     /* parse bit allocation */

  1160.     j = 0;

  1161.     for(i=0;i<bound;i++) {

  1162.         bit_alloc_bits = alloc_table[j];

  1163.         for(ch=0;ch<s->nb_channels;ch++) {

  1164.             bit_alloc[ch][i] = get_bits(&s->gb, bit_alloc_bits);

  1165.         }

  1166.         j += 1 << bit_alloc_bits;

  1167.     }

  1168.     for(i=bound;i<sblimit;i++) {

  1169.         bit_alloc_bits = alloc_table[j];

  1170.         v = get_bits(&s->gb, bit_alloc_bits);

  1171.         bit_alloc[0][i] = v;

  1172.         bit_alloc[1][i] = v;

  1173.         j += 1 << bit_alloc_bits;

  1174.     }

  1175. 

  1176. #ifdef DEBUG

  1177.     {

  1178.         for(ch=0;ch<s->nb_channels;ch++) {

  1179.             for(i=0;i<sblimit;i++)

  1180.                 dprintf(s->avctx, " %d", bit_alloc[ch][i]);

  1181.             dprintf(s->avctx, "\n");

  1182.         }

  1183.     }

  1184. #endif

  1185. 

  1186.     /* scale codes */

  1187.     for(i=0;i<sblimit;i++) {

  1188.         for(ch=0;ch<s->nb_channels;ch++) {

  1189.             if (bit_alloc[ch][i])

  1190.                 scale_code[ch][i] = get_bits(&s->gb, 2);

  1191.         }

  1192.     }

  1193. 

  1194.     /* scale factors */

  1195.     for(i=0;i<sblimit;i++) {

  1196.         for(ch=0;ch<s->nb_channels;ch++) {

  1197.             if (bit_alloc[ch][i]) {

  1198.                 sf = scale_factors[ch][i];

  1199.                 switch(scale_code[ch][i]) {

  1200.                 default:

  1201.                 case 0:

  1202.                     sf[0] = get_bits(&s->gb, 6);

  1203.                     sf[1] = get_bits(&s->gb, 6);

  1204.                     sf[2] = get_bits(&s->gb, 6);

  1205.                     break;

  1206.                 case 2:

  1207.                     sf[0] = get_bits(&s->gb, 6);

  1208.                     sf[1] = sf[0];

  1209.                     sf[2] = sf[0];

  1210.                     break;

  1211.                 case 1:

  1212.                     sf[0] = get_bits(&s->gb, 6);

  1213.                     sf[2] = get_bits(&s->gb, 6);

  1214.                     sf[1] = sf[0];

  1215.                     break;

  1216.                 case 3:

  1217.                     sf[0] = get_bits(&s->gb, 6);

  1218.                     sf[2] = get_bits(&s->gb, 6);

  1219.                     sf[1] = sf[2];

  1220.                     break;

  1221.                 }

  1222.             }

  1223.         }

  1224.     }

  1225. 

  1226. #ifdef DEBUG

  1227.     for(ch=0;ch<s->nb_channels;ch++) {

  1228.         for(i=0;i<sblimit;i++) {

  1229.             if (bit_alloc[ch][i]) {

  1230.                 sf = scale_factors[ch][i];

  1231.                 dprintf(s->avctx, " %d %d %d", sf[0], sf[1], sf[2]);

  1232.             } else {

  1233.                 dprintf(s->avctx, " -");

  1234.             }

  1235.         }

  1236.         dprintf(s->avctx, "\n");

  1237.     }

  1238. #endif

  1239. 

  1240.     /* samples */

  1241.     for(k=0;k<3;k++) {

  1242.         for(l=0;l<12;l+=3) {

  1243.             j = 0;

  1244.             for(i=0;i<bound;i++) {

  1245.                 bit_alloc_bits = alloc_table[j];

  1246.                 for(ch=0;ch<s->nb_channels;ch++) {

  1247.                     b = bit_alloc[ch][i];

  1248.                     if (b) {

  1249.                         scale = scale_factors[ch][i][k];

  1250.                         qindex = alloc_table[j+b];

  1251.                         bits = ff_mpa_quant_bits[qindex];

  1252.                         if (bits < 0) {

  1253.                             /* 3 values at the same time */

  1254.                             v = get_bits(&s->gb, -bits);

  1255.                             steps = ff_mpa_quant_steps[qindex];

  1256.                             s->sb_samples[ch][k * 12 + l + 0][i] =

  1257.                                 l2_unscale_group(steps, v % steps, scale);

  1258.                             v = v / steps;

  1259.                             s->sb_samples[ch][k * 12 + l + 1][i] =

  1260.                                 l2_unscale_group(steps, v % steps, scale);

  1261.                             v = v / steps;

  1262.                             s->sb_samples[ch][k * 12 + l + 2][i] =

  1263.                                 l2_unscale_group(steps, v, scale);

  1264.                         } else {

  1265.                             for(m=0;m<3;m++) {

  1266.                                 v = get_bits(&s->gb, bits);

  1267.                                 v = l1_unscale(bits - 1, v, scale);

  1268.                                 s->sb_samples[ch][k * 12 + l + m][i] = v;

  1269.                             }

  1270.                         }

  1271.                     } else {

  1272.                         s->sb_samples[ch][k * 12 + l + 0][i] = 0;

  1273.                         s->sb_samples[ch][k * 12 + l + 1][i] = 0;

  1274.                         s->sb_samples[ch][k * 12 + l + 2][i] = 0;

  1275.                     }

  1276.                 }

  1277.                 /* next subband in alloc table */

  1278.                 j += 1 << bit_alloc_bits;

  1279.             }

  1280.             /* XXX: find a way to avoid this duplication of code */

  1281.             for(i=bound;i<sblimit;i++) {

  1282.                 bit_alloc_bits = alloc_table[j];

  1283.                 b = bit_alloc[0][i];

  1284.                 if (b) {

  1285.                     int mant, scale0, scale1;

  1286.                     scale0 = scale_factors[0][i][k];

  1287.                     scale1 = scale_factors[1][i][k];

  1288.                     qindex = alloc_table[j+b];

  1289.                     bits = ff_mpa_quant_bits[qindex];

  1290.                     if (bits < 0) {

  1291.                         /* 3 values at the same time */

  1292.                         v = get_bits(&s->gb, -bits);

  1293.                         steps = ff_mpa_quant_steps[qindex];

  1294.                         mant = v % steps;

  1295.                         v = v / steps;

  1296.                         s->sb_samples[0][k * 12 + l + 0][i] =

  1297.                             l2_unscale_group(steps, mant, scale0);

  1298.                         s->sb_samples[1][k * 12 + l + 0][i] =

  1299.                             l2_unscale_group(steps, mant, scale1);

  1300.                         mant = v % steps;

  1301.                         v = v / steps;

  1302.                         s->sb_samples[0][k * 12 + l + 1][i] =

  1303.                             l2_unscale_group(steps, mant, scale0);

  1304.                         s->sb_samples[1][k * 12 + l + 1][i] =

  1305.                             l2_unscale_group(steps, mant, scale1);

  1306.                         s->sb_samples[0][k * 12 + l + 2][i] =

  1307.                             l2_unscale_group(steps, v, scale0);

  1308.                         s->sb_samples[1][k * 12 + l + 2][i] =

  1309.                             l2_unscale_group(steps, v, scale1);

  1310.                     } else {

  1311.                         for(m=0;m<3;m++) {

  1312.                             mant = get_bits(&s->gb, bits);

  1313.                             s->sb_samples[0][k * 12 + l + m][i] =

  1314.                                 l1_unscale(bits - 1, mant, scale0);

  1315.                             s->sb_samples[1][k * 12 + l + m][i] =

  1316.                                 l1_unscale(bits - 1, mant, scale1);

  1317.                         }

  1318.                     }

  1319.                 } else {

  1320.                     s->sb_samples[0][k * 12 + l + 0][i] = 0;

  1321.                     s->sb_samples[0][k * 12 + l + 1][i] = 0;

  1322.                     s->sb_samples[0][k * 12 + l + 2][i] = 0;

  1323.                     s->sb_samples[1][k * 12 + l + 0][i] = 0;

  1324.                     s->sb_samples[1][k * 12 + l + 1][i] = 0;

  1325.                     s->sb_samples[1][k * 12 + l + 2][i] = 0;

  1326.                 }

  1327.                 /* next subband in alloc table */

  1328.                 j += 1 << bit_alloc_bits;

  1329.             }

  1330.             /* fill remaining samples to zero */

  1331.             for(i=sblimit;i<SBLIMIT;i++) {

  1332.                 for(ch=0;ch<s->nb_channels;ch++) {

  1333.                     s->sb_samples[ch][k * 12 + l + 0][i] = 0;

  1334.                     s->sb_samples[ch][k * 12 + l + 1][i] = 0;

  1335.                     s->sb_samples[ch][k * 12 + l + 2][i] = 0;

  1336.                 }

  1337.             }

  1338.         }

  1339.     }

  1340.     return 3 * 12;

  1341. }

  1342. 

  1343. static inline void lsf_sf_expand(int *slen,

  1344.                                  int sf, int n1, int n2, int n3)

  1345. {

  1346.     if (n3) {

  1347.         slen[3] = sf % n3;

  1348.         sf /= n3;

  1349.     } else {

  1350.         slen[3] = 0;

  1351.     }

  1352.     if (n2) {

  1353.         slen[2] = sf % n2;

  1354.         sf /= n2;

  1355.     } else {

  1356.         slen[2] = 0;

  1357.     }

  1358.     slen[1] = sf % n1;

  1359.     sf /= n1;

  1360.     slen[0] = sf;

  1361. }

  1362. 

  1363. static void exponents_from_scale_factors(MPADecodeContext *s,

  1364.                                          GranuleDef *g,

  1365.                                          int16_t *exponents)

  1366. {

  1367.     const uint8_t *bstab, *pretab;

  1368.     int len, i, j, k, l, v0, shift, gain, gains[3];

  1369.     int16_t *exp_ptr;

  1370. 

  1371.     exp_ptr = exponents;

  1372.     gain = g->global_gain - 210;

  1373.     shift = g->scalefac_scale + 1;

  1374. 

  1375.     bstab = band_size_long[s->sample_rate_index];

  1376.     pretab = mpa_pretab[g->preflag];

  1377.     for(i=0;i<g->long_end;i++) {

  1378.         v0 = gain - ((g->scale_factors[i] + pretab[i]) << shift) + 400;

  1379.         len = bstab[i];

  1380.         for(j=len;j>0;j--)

  1381.             *exp_ptr++ = v0;

  1382.     }

  1383. 

  1384.     if (g->short_start < 13) {

  1385.         bstab = band_size_short[s->sample_rate_index];

  1386.         gains[0] = gain - (g->subblock_gain[0] << 3);

  1387.         gains[1] = gain - (g->subblock_gain[1] << 3);

  1388.         gains[2] = gain - (g->subblock_gain[2] << 3);

  1389.         k = g->long_end;

  1390.         for(i=g->short_start;i<13;i++) {

  1391.             len = bstab[i];

  1392.             for(l=0;l<3;l++) {

  1393.                 v0 = gains[l] - (g->scale_factors[k++] << shift) + 400;

  1394.                 for(j=len;j>0;j--)

  1395.                 *exp_ptr++ = v0;

  1396.             }

  1397.         }

  1398.     }

  1399. }

  1400. 

  1401. /* handle n = 0 too */

  1402. static inline int get_bitsz(GetBitContext *s, int n)

  1403. {

  1404.     if (n == 0)

  1405.         return 0;

  1406.     else

  1407.         return get_bits(s, n);

  1408. }

  1409. 

  1410. 

  1411. static void switch_buffer(MPADecodeContext *s, int *pos, int *end_pos, int *end_pos2){

  1412.     if(s->in_gb.buffer && *pos >= s->gb.size_in_bits){

  1413.         s->gb= s->in_gb;

  1414.         s->in_gb.buffer=NULL;

  1415.         assert((get_bits_count(&s->gb) & 7) == 0);

  1416.         skip_bits_long(&s->gb, *pos - *end_pos);

  1417.         *end_pos2=

  1418.         *end_pos= *end_pos2 + get_bits_count(&s->gb) - *pos;

  1419.         *pos= get_bits_count(&s->gb);

  1420.     }

  1421. }

  1422. 

  1423. static int huffman_decode(MPADecodeContext *s, GranuleDef *g,

  1424.                           int16_t *exponents, int end_pos2)

  1425. {

  1426.     int s_index;

  1427.     int i;

  1428.     int last_pos, bits_left;

  1429.     VLC *vlc;

  1430.     int end_pos= FFMIN(end_pos2, s->gb.size_in_bits);

  1431. 

  1432.     /* low frequencies (called big values) */

  1433.     s_index = 0;

  1434.     for(i=0;i<3;i++) {

  1435.         int j, k, l, linbits;

  1436.         j = g->region_size[i];

  1437.         if (j == 0)

  1438.             continue;

  1439.         /* select vlc table */

  1440.         k = g->table_select[i];

  1441.         l = mpa_huff_data[k][0];

  1442.         linbits = mpa_huff_data[k][1];

  1443.         vlc = &huff_vlc[l];

  1444. 

  1445.         if(!l){

  1446.             memset(&g->sb_hybrid[s_index], 0, sizeof(*g->sb_hybrid)*2*j);

  1447.             s_index += 2*j;

  1448.             continue;

  1449.         }

  1450. 

  1451.         /* read huffcode and compute each couple */

  1452.         for(;j>0;j--) {

  1453.             int exponent, x, y, v;

  1454.             int pos= get_bits_count(&s->gb);

  1455. 

  1456.             if (pos >= end_pos){

  1457. //                av_log(NULL, AV_LOG_ERROR, "pos: %d %d %d %d\n", pos, end_pos, end_pos2, s_index);

  1458.                 switch_buffer(s, &pos, &end_pos, &end_pos2);

  1459. //                av_log(NULL, AV_LOG_ERROR, "new pos: %d %d\n", pos, end_pos);

  1460.                 if(pos >= end_pos)

  1461.                     break;

  1462.             }

  1463.             y = get_vlc2(&s->gb, vlc->table, 7, 3);

  1464. 

  1465.             if(!y){

  1466.                 g->sb_hybrid[s_index  ] =

  1467.                 g->sb_hybrid[s_index+1] = 0;

  1468.                 s_index += 2;

  1469.                 continue;

  1470.             }

  1471. 

  1472.             exponent= exponents[s_index];

  1473. 

  1474.             dprintf(s->avctx, "region=%d n=%d x=%d y=%d exp=%d\n",

  1475.                     i, g->region_size[i] - j, x, y, exponent);

  1476.             if(y&16){

  1477.                 x = y >> 5;

  1478.                 y = y & 0x0f;

  1479.                 if (x < 15){

  1480.                     v = expval_table[ exponent ][ x ];

  1481. //                      v = expval_table[ (exponent&3) ][ x ] >> FFMIN(0 - (exponent>>2), 31);

  1482.                 }else{

  1483.                     x += get_bitsz(&s->gb, linbits);

  1484.                     v = l3_unscale(x, exponent);

  1485.                 }

  1486.                 if (get_bits1(&s->gb))

  1487.                     v = -v;

  1488.                 g->sb_hybrid[s_index] = v;

  1489.                 if (y < 15){

  1490.                     v = expval_table[ exponent ][ y ];

  1491.                 }else{

  1492.                     y += get_bitsz(&s->gb, linbits);

  1493.                     v = l3_unscale(y, exponent);

  1494.                 }

  1495.                 if (get_bits1(&s->gb))

  1496.                     v = -v;

  1497.                 g->sb_hybrid[s_index+1] = v;

  1498.             }else{

  1499.                 x = y >> 5;

  1500.                 y = y & 0x0f;

  1501.                 x += y;

  1502.                 if (x < 15){

  1503.                     v = expval_table[ exponent ][ x ];

  1504.                 }else{

  1505.                     x += get_bitsz(&s->gb, linbits);

  1506.                     v = l3_unscale(x, exponent);

  1507.                 }

  1508.                 if (get_bits1(&s->gb))

  1509.                     v = -v;

  1510.                 g->sb_hybrid[s_index+!!y] = v;

  1511.                 g->sb_hybrid[s_index+ !y] = 0;

  1512.             }

  1513.             s_index+=2;

  1514.         }

  1515.     }

  1516. 

  1517.     /* high frequencies */

  1518.     vlc = &huff_quad_vlc[g->count1table_select];

  1519.     last_pos=0;

  1520.     while (s_index <= 572) {

  1521.         int pos, code;

  1522.         pos = get_bits_count(&s->gb);

  1523.         if (pos >= end_pos) {

  1524.             if (pos > end_pos2 && last_pos){

  1525.                 /* some encoders generate an incorrect size for this

  1526.                    part. We must go back into the data */

  1527.                 s_index -= 4;

  1528.                 skip_bits_long(&s->gb, last_pos - pos);

  1529.                 av_log(NULL, AV_LOG_INFO, "overread, skip %d enddists: %d %d\n", last_pos - pos, end_pos-pos, end_pos2-pos);

  1530.                 if(s->error_resilience >= FF_ER_COMPLIANT)

  1531.                     s_index=0;

  1532.                 break;

  1533.             }

  1534. //                av_log(NULL, AV_LOG_ERROR, "pos2: %d %d %d %d\n", pos, end_pos, end_pos2, s_index);

  1535.             switch_buffer(s, &pos, &end_pos, &end_pos2);

  1536. //                av_log(NULL, AV_LOG_ERROR, "new pos2: %d %d %d\n", pos, end_pos, s_index);

  1537.             if(pos >= end_pos)

  1538.                 break;

  1539.         }

  1540.         last_pos= pos;

  1541. 

  1542.         code = get_vlc2(&s->gb, vlc->table, vlc->bits, 1);

  1543.         dprintf(s->avctx, "t=%d code=%d\n", g->count1table_select, code);

  1544.         g->sb_hybrid[s_index+0]=

  1545.         g->sb_hybrid[s_index+1]=

  1546.         g->sb_hybrid[s_index+2]=

  1547.         g->sb_hybrid[s_index+3]= 0;

  1548.         while(code){

  1549.             static const int idxtab[16]={3,3,2,2,1,1,1,1,0,0,0,0,0,0,0,0};

  1550.             int v;

  1551.             int pos= s_index+idxtab[code];

  1552.             code ^= 8>>idxtab[code];

  1553.             v = exp_table[ exponents[pos] ];

  1554. //            v = exp_table[ (exponents[pos]&3) ] >> FFMIN(0 - (exponents[pos]>>2), 31);

  1555.             if(get_bits1(&s->gb))

  1556.                 v = -v;

  1557.             g->sb_hybrid[pos] = v;

  1558.         }

  1559.         s_index+=4;

  1560.     }

  1561.     /* skip extension bits */

  1562.     bits_left = end_pos2 - get_bits_count(&s->gb);

  1563. //av_log(NULL, AV_LOG_ERROR, "left:%d buf:%p\n", bits_left, s->in_gb.buffer);

  1564.     if (bits_left < 0/* || bits_left > 500*/) {

  1565.         av_log(NULL, AV_LOG_ERROR, "bits_left=%d\n", bits_left);

  1566.         s_index=0;

  1567.     }else if(bits_left > 0 && s->error_resilience >= FF_ER_AGGRESSIVE){

  1568.         av_log(NULL, AV_LOG_ERROR, "bits_left=%d\n", bits_left);

  1569.         s_index=0;

  1570.     }

  1571.     memset(&g->sb_hybrid[s_index], 0, sizeof(*g->sb_hybrid)*(576 - s_index));

  1572.     skip_bits_long(&s->gb, bits_left);

  1573. 

  1574.     i= get_bits_count(&s->gb);

  1575.     switch_buffer(s, &i, &end_pos, &end_pos2);

  1576. 

  1577.     return 0;

  1578. }

  1579. 

  1580. /* Reorder short blocks from bitstream order to interleaved order. It

  1581.    would be faster to do it in parsing, but the code would be far more

  1582.    complicated */

  1583. static void reorder_block(MPADecodeContext *s, GranuleDef *g)

  1584. {

  1585.     int i, j, len;

  1586.     int32_t *ptr, *dst, *ptr1;

  1587.     int32_t tmp[576];

  1588. 

  1589.     if (g->block_type != 2)

  1590.         return;

  1591. 

  1592.     if (g->switch_point) {

  1593.         if (s->sample_rate_index != 8) {

  1594.             ptr = g->sb_hybrid + 36;

  1595.         } else {

  1596.             ptr = g->sb_hybrid + 48;

  1597.         }

  1598.     } else {

  1599.         ptr = g->sb_hybrid;

  1600.     }

  1601. 

  1602.     for(i=g->short_start;i<13;i++) {

  1603.         len = band_size_short[s->sample_rate_index][i];

  1604.         ptr1 = ptr;

  1605.         dst = tmp;

  1606.         for(j=len;j>0;j--) {

  1607.             *dst++ = ptr[0*len];

  1608.             *dst++ = ptr[1*len];

  1609.             *dst++ = ptr[2*len];

  1610.             ptr++;

  1611.         }

  1612.         ptr+=2*len;

  1613.         memcpy(ptr1, tmp, len * 3 * sizeof(*ptr1));

  1614.     }

  1615. }

  1616. 

  1617. #define ISQRT2 FIXR(0.70710678118654752440)

  1618. 

  1619. static void compute_stereo(MPADecodeContext *s,

  1620.                            GranuleDef *g0, GranuleDef *g1)

  1621. {

  1622.     int i, j, k, l;

  1623.     int32_t v1, v2;

  1624.     int sf_max, tmp0, tmp1, sf, len, non_zero_found;

  1625.     int32_t (*is_tab)[16];

  1626.     int32_t *tab0, *tab1;

  1627.     int non_zero_found_short[3];

  1628. 

  1629.     /* intensity stereo */

  1630.     if (s->mode_ext & MODE_EXT_I_STEREO) {

  1631.         if (!s->lsf) {

  1632.             is_tab = is_table;

  1633.             sf_max = 7;

  1634.         } else {

  1635.             is_tab = is_table_lsf[g1->scalefac_compress & 1];

  1636.             sf_max = 16;

  1637.         }

  1638. 

  1639.         tab0 = g0->sb_hybrid + 576;

  1640.         tab1 = g1->sb_hybrid + 576;

  1641. 

  1642.         non_zero_found_short[0] = 0;

  1643.         non_zero_found_short[1] = 0;

  1644.         non_zero_found_short[2] = 0;

  1645.         k = (13 - g1->short_start) * 3 + g1->long_end - 3;

  1646.         for(i = 12;i >= g1->short_start;i--) {

  1647.             /* for last band, use previous scale factor */

  1648.             if (i != 11)

  1649.                 k -= 3;

  1650.             len = band_size_short[s->sample_rate_index][i];

  1651.             for(l=2;l>=0;l--) {

  1652.                 tab0 -= len;

  1653.                 tab1 -= len;

  1654.                 if (!non_zero_found_short[l]) {

  1655.                     /* test if non zero band. if so, stop doing i-stereo */

  1656.                     for(j=0;j<len;j++) {

  1657.                         if (tab1[j] != 0) {

  1658.                             non_zero_found_short[l] = 1;

  1659.                             goto found1;

  1660.                         }

  1661.                     }

  1662.                     sf = g1->scale_factors[k + l];

  1663.                     if (sf >= sf_max)

  1664.                         goto found1;

  1665. 

  1666.                     v1 = is_tab[0][sf];

  1667.                     v2 = is_tab[1][sf];

  1668.                     for(j=0;j<len;j++) {

  1669.                         tmp0 = tab0[j];

  1670.                         tab0[j] = MULL(tmp0, v1);

  1671.                         tab1[j] = MULL(tmp0, v2);

  1672.                     }

  1673.                 } else {

  1674.                 found1:

  1675.                     if (s->mode_ext & MODE_EXT_MS_STEREO) {

  1676.                         /* lower part of the spectrum : do ms stereo

  1677.                            if enabled */

  1678.                         for(j=0;j<len;j++) {

  1679.                             tmp0 = tab0[j];

  1680.                             tmp1 = tab1[j];

  1681.                             tab0[j] = MULL(tmp0 + tmp1, ISQRT2);

  1682.                             tab1[j] = MULL(tmp0 - tmp1, ISQRT2);

  1683.                         }

  1684.                     }

  1685.                 }

  1686.             }

  1687.         }

  1688. 

  1689.         non_zero_found = non_zero_found_short[0] |

  1690.             non_zero_found_short[1] |

  1691.             non_zero_found_short[2];

  1692. 

  1693.         for(i = g1->long_end - 1;i >= 0;i--) {

  1694.             len = band_size_long[s->sample_rate_index][i];

  1695.             tab0 -= len;

  1696.             tab1 -= len;

  1697.             /* test if non zero band. if so, stop doing i-stereo */

  1698.             if (!non_zero_found) {

  1699.                 for(j=0;j<len;j++) {

  1700.                     if (tab1[j] != 0) {

  1701.                         non_zero_found = 1;

  1702.                         goto found2;

  1703.                     }

  1704.                 }

  1705.                 /* for last band, use previous scale factor */

  1706.                 k = (i == 21) ? 20 : i;

  1707.                 sf = g1->scale_factors[k];

  1708.                 if (sf >= sf_max)

  1709.                     goto found2;

  1710.                 v1 = is_tab[0][sf];

  1711.                 v2 = is_tab[1][sf];

  1712.                 for(j=0;j<len;j++) {

  1713.                     tmp0 = tab0[j];

  1714.                     tab0[j] = MULL(tmp0, v1);

  1715.                     tab1[j] = MULL(tmp0, v2);

  1716.                 }

  1717.             } else {

  1718.             found2:

  1719.                 if (s->mode_ext & MODE_EXT_MS_STEREO) {

  1720.                     /* lower part of the spectrum : do ms stereo

  1721.                        if enabled */

  1722.                     for(j=0;j<len;j++) {

  1723.                         tmp0 = tab0[j];

  1724.                         tmp1 = tab1[j];

  1725.                         tab0[j] = MULL(tmp0 + tmp1, ISQRT2);

  1726.                         tab1[j] = MULL(tmp0 - tmp1, ISQRT2);

  1727.                     }

  1728.                 }

  1729.             }

  1730.         }

  1731.     } else if (s->mode_ext & MODE_EXT_MS_STEREO) {

  1732.         /* ms stereo ONLY */

  1733.         /* NOTE: the 1/sqrt(2) normalization factor is included in the

  1734.            global gain */

  1735.         tab0 = g0->sb_hybrid;

  1736.         tab1 = g1->sb_hybrid;

  1737.         for(i=0;i<576;i++) {

  1738.             tmp0 = tab0[i];

  1739.             tmp1 = tab1[i];

  1740.             tab0[i] = tmp0 + tmp1;

  1741.             tab1[i] = tmp0 - tmp1;

  1742.         }

  1743.     }

  1744. }

  1745. 

  1746. static void compute_antialias_integer(MPADecodeContext *s,

  1747.                               GranuleDef *g)

  1748. {

  1749.     int32_t *ptr, *csa;

  1750.     int n, i;

  1751. 

  1752.     /* we antialias only "long" bands */

  1753.     if (g->block_type == 2) {

  1754.         if (!g->switch_point)

  1755.             return;

  1756.         /* XXX: check this for 8000Hz case */

  1757.         n = 1;

  1758.     } else {

  1759.         n = SBLIMIT - 1;

  1760.     }

  1761. 

  1762.     ptr = g->sb_hybrid + 18;

  1763.     for(i = n;i > 0;i--) {

  1764.         int tmp0, tmp1, tmp2;

  1765.         csa = &csa_table[0][0];

  1766. #define INT_AA(j) \

  1767.             tmp0 = ptr[-1-j];\

  1768.             tmp1 = ptr[   j];\

  1769.             tmp2= MULH(tmp0 + tmp1, csa[0+4*j]);\

  1770.             ptr[-1-j] = 4*(tmp2 - MULH(tmp1, csa[2+4*j]));\

  1771.             ptr[   j] = 4*(tmp2 + MULH(tmp0, csa[3+4*j]));

  1772. 

  1773.         INT_AA(0)

  1774.         INT_AA(1)

  1775.         INT_AA(2)

  1776.         INT_AA(3)

  1777.         INT_AA(4)

  1778.         INT_AA(5)

  1779.         INT_AA(6)

  1780.         INT_AA(7)

  1781. 

  1782.         ptr += 18;

  1783.     }

  1784. }

  1785. 

  1786. static void compute_antialias_float(MPADecodeContext *s,

  1787.                               GranuleDef *g)

  1788. {

  1789.     int32_t *ptr;

  1790.     int n, i;

  1791. 

  1792.     /* we antialias only "long" bands */

  1793.     if (g->block_type == 2) {

  1794.         if (!g->switch_point)

  1795.             return;

  1796.         /* XXX: check this for 8000Hz case */

  1797.         n = 1;

  1798.     } else {

  1799.         n = SBLIMIT - 1;

  1800.     }

  1801. 

  1802.     ptr = g->sb_hybrid + 18;

  1803.     for(i = n;i > 0;i--) {

  1804.         float tmp0, tmp1;

  1805.         float *csa = &csa_table_float[0][0];

  1806. #define FLOAT_AA(j)\

  1807.         tmp0= ptr[-1-j];\

  1808.         tmp1= ptr[   j];\

  1809.         ptr[-1-j] = lrintf(tmp0 * csa[0+4*j] - tmp1 * csa[1+4*j]);\

  1810.         ptr[   j] = lrintf(tmp0 * csa[1+4*j] + tmp1 * csa[0+4*j]);

  1811. 

  1812.         FLOAT_AA(0)

  1813.         FLOAT_AA(1)

  1814.         FLOAT_AA(2)

  1815.         FLOAT_AA(3)

  1816.         FLOAT_AA(4)

  1817.         FLOAT_AA(5)

  1818.         FLOAT_AA(6)

  1819.         FLOAT_AA(7)

  1820. 

  1821.         ptr += 18;

  1822.     }

  1823. }

  1824. 

  1825. static void compute_imdct(MPADecodeContext *s,

  1826.                           GranuleDef *g,

  1827.                           int32_t *sb_samples,

  1828.                           int32_t *mdct_buf)

  1829. {

  1830.     int32_t *ptr, *win, *win1, *buf, *out_ptr, *ptr1;

  1831.     int32_t out2[12];

  1832.     int i, j, mdct_long_end, v, sblimit;

  1833. 

  1834.     /* find last non zero block */

  1835.     ptr = g->sb_hybrid + 576;

  1836.     ptr1 = g->sb_hybrid + 2 * 18;

  1837.     while (ptr >= ptr1) {

  1838.         ptr -= 6;

  1839.         v = ptr[0] | ptr[1] | ptr[2] | ptr[3] | ptr[4] | ptr[5];

  1840.         if (v != 0)

  1841.             break;

  1842.     }

  1843.     sblimit = ((ptr - g->sb_hybrid) / 18) + 1;

  1844. 

  1845.     if (g->block_type == 2) {

  1846.         /* XXX: check for 8000 Hz */

  1847.         if (g->switch_point)

  1848.             mdct_long_end = 2;

  1849.         else

  1850.             mdct_long_end = 0;

  1851.     } else {

  1852.         mdct_long_end = sblimit;

  1853.     }

  1854. 

  1855.     buf = mdct_buf;

  1856.     ptr = g->sb_hybrid;

  1857.     for(j=0;j<mdct_long_end;j++) {

  1858.         /* apply window & overlap with previous buffer */

  1859.         out_ptr = sb_samples + j;

  1860.         /* select window */

  1861.         if (g->switch_point && j < 2)

  1862.             win1 = mdct_win[0];

  1863.         else

  1864.             win1 = mdct_win[g->block_type];

  1865.         /* select frequency inversion */

  1866.         win = win1 + ((4 * 36) & -(j & 1));

  1867.         imdct36(out_ptr, buf, ptr, win);

  1868.         out_ptr += 18*SBLIMIT;

  1869.         ptr += 18;

  1870.         buf += 18;

  1871.     }

  1872.     for(j=mdct_long_end;j<sblimit;j++) {

  1873.         /* select frequency inversion */

  1874.         win = mdct_win[2] + ((4 * 36) & -(j & 1));

  1875.         out_ptr = sb_samples + j;

  1876. 

  1877.         for(i=0; i<6; i++){

  1878.             *out_ptr = buf[i];

  1879.             out_ptr += SBLIMIT;

  1880.         }

  1881.         imdct12(out2, ptr + 0);

  1882.         for(i=0;i<6;i++) {

  1883.             *out_ptr = MULH(out2[i], win[i]) + buf[i + 6*1];

  1884.             buf[i + 6*2] = MULH(out2[i + 6], win[i + 6]);

  1885.             out_ptr += SBLIMIT;

  1886.         }

  1887.         imdct12(out2, ptr + 1);

  1888.         for(i=0;i<6;i++) {

  1889.             *out_ptr = MULH(out2[i], win[i]) + buf[i + 6*2];

  1890.             buf[i + 6*0] = MULH(out2[i + 6], win[i + 6]);

  1891.             out_ptr += SBLIMIT;

  1892.         }

  1893.         imdct12(out2, ptr + 2);

  1894.         for(i=0;i<6;i++) {

  1895.             buf[i + 6*0] = MULH(out2[i], win[i]) + buf[i + 6*0];

  1896.             buf[i + 6*1] = MULH(out2[i + 6], win[i + 6]);

  1897.             buf[i + 6*2] = 0;

  1898.         }

  1899.         ptr += 18;

  1900.         buf += 18;

  1901.     }

  1902.     /* zero bands */

  1903.     for(j=sblimit;j<SBLIMIT;j++) {

  1904.         /* overlap */

  1905.         out_ptr = sb_samples + j;

  1906.         for(i=0;i<18;i++) {

  1907.             *out_ptr = buf[i];

  1908.             buf[i] = 0;

  1909.             out_ptr += SBLIMIT;

  1910.         }

  1911.         buf += 18;

  1912.     }

  1913. }

  1914. 

  1915. #if defined(DEBUG)

  1916. void sample_dump(int fnum, int32_t *tab, int n)

  1917. {

  1918.     static FILE *files[16], *f;

  1919.     char buf[512];

  1920.     int i;

  1921.     int32_t v;

  1922. 

  1923.     f = files[fnum];

  1924.     if (!f) {

  1925.         snprintf(buf, sizeof(buf), "/tmp/out%d.%s.pcm",

  1926.                 fnum,

  1927. #ifdef USE_HIGHPRECISION

  1928.                 "hp"

  1929. #else

  1930.                 "lp"

  1931. #endif

  1932.                 );

  1933.         f = fopen(buf, "w");

  1934.         if (!f)

  1935.             return;

  1936.         files[fnum] = f;

  1937.     }

  1938. 

  1939.     if (fnum == 0) {

  1940.         static int pos = 0;

  1941.         av_log(NULL, AV_LOG_DEBUG, "pos=%d\n", pos);

  1942.         for(i=0;i<n;i++) {

  1943.             av_log(NULL, AV_LOG_DEBUG, " %0.4f", (double)tab[i] / FRAC_ONE);

  1944.             if ((i % 18) == 17)

  1945.                 av_log(NULL, AV_LOG_DEBUG, "\n");

  1946.         }

  1947.         pos += n;

  1948.     }

  1949.     for(i=0;i<n;i++) {

  1950.         /* normalize to 23 frac bits */

  1951.         v = tab[i] << (23 - FRAC_BITS);

  1952.         fwrite(&v, 1, sizeof(int32_t), f);

  1953.     }

  1954. }

  1955. #endif

  1956. 

  1957. 

  1958. /* main layer3 decoding function */

  1959. static int mp_decode_layer3(MPADecodeContext *s)

  1960. {

  1961.     int nb_granules, main_data_begin, private_bits;

  1962.     int gr, ch, blocksplit_flag, i, j, k, n, bits_pos;

  1963.     GranuleDef granules[2][2], *g;

  1964.     int16_t exponents[576];

  1965. 

  1966.     /* read side info */

  1967.     if (s->lsf) {

  1968.         main_data_begin = get_bits(&s->gb, 8);

  1969.         private_bits = get_bits(&s->gb, s->nb_channels);

  1970.         nb_granules = 1;

  1971.     } else {

  1972.         main_data_begin = get_bits(&s->gb, 9);

  1973.         if (s->nb_channels == 2)

  1974.             private_bits = get_bits(&s->gb, 3);

  1975.         else

  1976.             private_bits = get_bits(&s->gb, 5);

  1977.         nb_granules = 2;

  1978.         for(ch=0;ch<s->nb_channels;ch++) {

  1979.             granules[ch][0].scfsi = 0; /* all scale factors are transmitted */

  1980.             granules[ch][1].scfsi = get_bits(&s->gb, 4);

  1981.         }

  1982.     }

  1983. 

  1984.     for(gr=0;gr<nb_granules;gr++) {

  1985.         for(ch=0;ch<s->nb_channels;ch++) {

  1986.             dprintf(s->avctx, "gr=%d ch=%d: side_info\n", gr, ch);

  1987.             g = &granules[ch][gr];

  1988.             g->part2_3_length = get_bits(&s->gb, 12);

  1989.             g->big_values = get_bits(&s->gb, 9);

  1990.             if(g->big_values > 288){

  1991.                 av_log(s->avctx, AV_LOG_ERROR, "big_values too big\n");

  1992.                 return -1;

  1993.             }

  1994. 

  1995.             g->global_gain = get_bits(&s->gb, 8);

  1996.             /* if MS stereo only is selected, we precompute the

  1997.                1/sqrt(2) renormalization factor */

  1998.             if ((s->mode_ext & (MODE_EXT_MS_STEREO | MODE_EXT_I_STEREO)) ==

  1999.                 MODE_EXT_MS_STEREO)

  2000.                 g->global_gain -= 2;

  2001.             if (s->lsf)

  2002.                 g->scalefac_compress = get_bits(&s->gb, 9);

  2003.             else

  2004.                 g->scalefac_compress = get_bits(&s->gb, 4);

  2005.             blocksplit_flag = get_bits1(&s->gb);

  2006.             if (blocksplit_flag) {

  2007.                 g->block_type = get_bits(&s->gb, 2);

  2008.                 if (g->block_type == 0){

  2009.                     av_log(NULL, AV_LOG_ERROR, "invalid block type\n");

  2010.                     return -1;

  2011.                 }

  2012.                 g->switch_point = get_bits1(&s->gb);

  2013.                 for(i=0;i<2;i++)

  2014.                     g->table_select[i] = get_bits(&s->gb, 5);

  2015.                 for(i=0;i<3;i++)

  2016.                     g->subblock_gain[i] = get_bits(&s->gb, 3);

  2017.                 /* compute huffman coded region sizes */

  2018.                 if (g->block_type == 2)

  2019.                     g->region_size[0] = (36 / 2);

  2020.                 else {

  2021.                     if (s->sample_rate_index <= 2)

  2022.                         g->region_size[0] = (36 / 2);

  2023.                     else if (s->sample_rate_index != 8)

  2024.                         g->region_size[0] = (54 / 2);

  2025.                     else

  2026.                         g->region_size[0] = (108 / 2);

  2027.                 }

  2028.                 g->region_size[1] = (576 / 2);

  2029.             } else {

  2030.                 int region_address1, region_address2, l;

  2031.                 g->block_type = 0;

  2032.                 g->switch_point = 0;

  2033.                 for(i=0;i<3;i++)

  2034.                     g->table_select[i] = get_bits(&s->gb, 5);

  2035.                 /* compute huffman coded region sizes */

  2036.                 region_address1 = get_bits(&s->gb, 4);

  2037.                 region_address2 = get_bits(&s->gb, 3);

  2038.                 dprintf(s->avctx, "region1=%d region2=%d\n",

  2039.                         region_address1, region_address2);

  2040.                 g->region_size[0] =

  2041.                     band_index_long[s->sample_rate_index][region_address1 + 1] >> 1;

  2042.                 l = region_address1 + region_address2 + 2;

  2043.                 /* should not overflow */

  2044.                 if (l > 22)

  2045.                     l = 22;

  2046.                 g->region_size[1] =

  2047.                     band_index_long[s->sample_rate_index][l] >> 1;

  2048.             }

  2049.             /* convert region offsets to region sizes and truncate

  2050.                size to big_values */

  2051.             g->region_size[2] = (576 / 2);

  2052.             j = 0;

  2053.             for(i=0;i<3;i++) {

  2054.                 k = FFMIN(g->region_size[i], g->big_values);

  2055.                 g->region_size[i] = k - j;

  2056.                 j = k;

  2057.             }

  2058. 

  2059.             /* compute band indexes */

  2060.             if (g->block_type == 2) {

  2061.                 if (g->switch_point) {

  2062.                     /* if switched mode, we handle the 36 first samples as

  2063.                        long blocks.  For 8000Hz, we handle the 48 first

  2064.                        exponents as long blocks (XXX: check this!) */

  2065.                     if (s->sample_rate_index <= 2)

  2066.                         g->long_end = 8;

  2067.                     else if (s->sample_rate_index != 8)

  2068.                         g->long_end = 6;

  2069.                     else

  2070.                         g->long_end = 4; /* 8000 Hz */

  2071. 

  2072.                     g->short_start = 2 + (s->sample_rate_index != 8);

  2073.                 } else {

  2074.                     g->long_end = 0;

  2075.                     g->short_start = 0;

  2076.                 }

  2077.             } else {

  2078.                 g->short_start = 13;

  2079.                 g->long_end = 22;

  2080.             }

  2081. 

  2082.             g->preflag = 0;

  2083.             if (!s->lsf)

  2084.                 g->preflag = get_bits1(&s->gb);

  2085.             g->scalefac_scale = get_bits1(&s->gb);

  2086.             g->count1table_select = get_bits1(&s->gb);

  2087.             dprintf(s->avctx, "block_type=%d switch_point=%d\n",

  2088.                     g->block_type, g->switch_point);

  2089.         }

  2090.     }

  2091. 

  2092.   if (!s->adu_mode) {

  2093.     const uint8_t *ptr = s->gb.buffer + (get_bits_count(&s->gb)>>3);

  2094.     assert((get_bits_count(&s->gb) & 7) == 0);

  2095.     /* now we get bits from the main_data_begin offset */

  2096.     dprintf(s->avctx, "seekback: %d\n", main_data_begin);

  2097. //av_log(NULL, AV_LOG_ERROR, "backstep:%d, lastbuf:%d\n", main_data_begin, s->last_buf_size);

  2098. 

  2099.     memcpy(s->last_buf + s->last_buf_size, ptr, EXTRABYTES);

  2100.     s->in_gb= s->gb;

  2101.         init_get_bits(&s->gb, s->last_buf, s->last_buf_size*8);

  2102.         skip_bits_long(&s->gb, 8*(s->last_buf_size - main_data_begin));

  2103.   }

  2104. 

  2105.     for(gr=0;gr<nb_granules;gr++) {

  2106.         for(ch=0;ch<s->nb_channels;ch++) {

  2107.             g = &granules[ch][gr];

  2108.             if(get_bits_count(&s->gb)<0){

  2109.                 av_log(NULL, AV_LOG_ERROR, "mdb:%d, lastbuf:%d skipping granule %d\n",

  2110.                                             main_data_begin, s->last_buf_size, gr);

  2111.                 skip_bits_long(&s->gb, g->part2_3_length);

  2112.                 memset(g->sb_hybrid, 0, sizeof(g->sb_hybrid));

  2113.                 if(get_bits_count(&s->gb) >= s->gb.size_in_bits && s->in_gb.buffer){

  2114.                     skip_bits_long(&s->in_gb, get_bits_count(&s->gb) - s->gb.size_in_bits);

  2115.                     s->gb= s->in_gb;

  2116.                     s->in_gb.buffer=NULL;

  2117.                 }

  2118.                 continue;

  2119.             }

  2120. 

  2121.             bits_pos = get_bits_count(&s->gb);

  2122. 

  2123.             if (!s->lsf) {

  2124.                 uint8_t *sc;

  2125.                 int slen, slen1, slen2;

  2126. 

  2127.                 /* MPEG1 scale factors */

  2128.                 slen1 = slen_table[0][g->scalefac_compress];

  2129.                 slen2 = slen_table[1][g->scalefac_compress];

  2130.                 dprintf(s->avctx, "slen1=%d slen2=%d\n", slen1, slen2);

  2131.                 if (g->block_type == 2) {

  2132.                     n = g->switch_point ? 17 : 18;

  2133.                     j = 0;

  2134.                     if(slen1){

  2135.                         for(i=0;i<n;i++)

  2136.                             g->scale_factors[j++] = get_bits(&s->gb, slen1);

  2137.                     }else{

  2138.                         for(i=0;i<n;i++)

  2139.                             g->scale_factors[j++] = 0;

  2140.                     }

  2141.                     if(slen2){

  2142.                         for(i=0;i<18;i++)

  2143.                             g->scale_factors[j++] = get_bits(&s->gb, slen2);

  2144.                         for(i=0;i<3;i++)

  2145.                             g->scale_factors[j++] = 0;

  2146.                     }else{

  2147.                         for(i=0;i<21;i++)

  2148.                             g->scale_factors[j++] = 0;

  2149.                     }

  2150.                 } else {

  2151.                     sc = granules[ch][0].scale_factors;

  2152.                     j = 0;

  2153.                     for(k=0;k<4;k++) {

  2154.                         n = (k == 0 ? 6 : 5);

  2155.                         if ((g->scfsi & (0x8 >> k)) == 0) {

  2156.                             slen = (k < 2) ? slen1 : slen2;

  2157.                             if(slen){

  2158.                                 for(i=0;i<n;i++)

  2159.                                     g->scale_factors[j++] = get_bits(&s->gb, slen);

  2160.                             }else{

  2161.                                 for(i=0;i<n;i++)

  2162.                                     g->scale_factors[j++] = 0;

  2163.                             }

  2164.                         } else {

  2165.                             /* simply copy from last granule */

  2166.                             for(i=0;i<n;i++) {

  2167.                                 g->scale_factors[j] = sc[j];

  2168.                                 j++;

  2169.                             }

  2170.                         }

  2171.                     }

  2172.                     g->scale_factors[j++] = 0;

  2173.                 }

  2174. #if defined(DEBUG)

  2175.                 {

  2176.                     dprintf(s->avctx, "scfsi=%x gr=%d ch=%d scale_factors:\n",

  2177.                            g->scfsi, gr, ch);

  2178.                     for(i=0;i<j;i++)

  2179.                         dprintf(s->avctx, " %d", g->scale_factors[i]);

  2180.                     dprintf(s->avctx, "\n");

  2181.                 }

  2182. #endif

  2183.             } else {

  2184.                 int tindex, tindex2, slen[4], sl, sf;

  2185. 

  2186.                 /* LSF scale factors */

  2187.                 if (g->block_type == 2) {

  2188.                     tindex = g->switch_point ? 2 : 1;

  2189.                 } else {

  2190.                     tindex = 0;

  2191.                 }

  2192.                 sf = g->scalefac_compress;

  2193.                 if ((s->mode_ext & MODE_EXT_I_STEREO) && ch == 1) {

  2194.                     /* intensity stereo case */

  2195.                     sf >>= 1;

  2196.                     if (sf < 180) {

  2197.                         lsf_sf_expand(slen, sf, 6, 6, 0);

  2198.                         tindex2 = 3;

  2199.                     } else if (sf < 244) {

  2200.                         lsf_sf_expand(slen, sf - 180, 4, 4, 0);

  2201.                         tindex2 = 4;

  2202.                     } else {

  2203.                         lsf_sf_expand(slen, sf - 244, 3, 0, 0);

  2204.                         tindex2 = 5;

  2205.                     }

  2206.                 } else {

  2207.                     /* normal case */

  2208.                     if (sf < 400) {

  2209.                         lsf_sf_expand(slen, sf, 5, 4, 4);

  2210.                         tindex2 = 0;

  2211.                     } else if (sf < 500) {

  2212.                         lsf_sf_expand(slen, sf - 400, 5, 4, 0);

  2213.                         tindex2 = 1;

  2214.                     } else {

  2215.                         lsf_sf_expand(slen, sf - 500, 3, 0, 0);

  2216.                         tindex2 = 2;

  2217.                         g->preflag = 1;

  2218.                     }

  2219.                 }

  2220. 

  2221.                 j = 0;

  2222.                 for(k=0;k<4;k++) {

  2223.                     n = lsf_nsf_table[tindex2][tindex][k];

  2224.                     sl = slen[k];

  2225.                     if(sl){

  2226.                         for(i=0;i<n;i++)

  2227.                             g->scale_factors[j++] = get_bits(&s->gb, sl);

  2228.                     }else{

  2229.                         for(i=0;i<n;i++)

  2230.                             g->scale_factors[j++] = 0;

  2231.                     }

  2232.                 }

  2233.                 /* XXX: should compute exact size */

  2234.                 for(;j<40;j++)

  2235.                     g->scale_factors[j] = 0;

  2236. #if defined(DEBUG)

  2237.                 {

  2238.                     dprintf(s->avctx, "gr=%d ch=%d scale_factors:\n",

  2239.                            gr, ch);

  2240.                     for(i=0;i<40;i++)

  2241.                         dprintf(s->avctx, " %d", g->scale_factors[i]);

  2242.                     dprintf(s->avctx, "\n");

  2243.                 }

  2244. #endif

  2245.             }

  2246. 

  2247.             exponents_from_scale_factors(s, g, exponents);

  2248. 

  2249.             /* read Huffman coded residue */

  2250.             huffman_decode(s, g, exponents, bits_pos + g->part2_3_length);

  2251. #if defined(DEBUG)

  2252.             sample_dump(0, g->sb_hybrid, 576);

  2253. #endif

  2254.         } /* ch */

  2255. 

  2256.         if (s->nb_channels == 2)

  2257.             compute_stereo(s, &granules[0][gr], &granules[1][gr]);

  2258. 

  2259.         for(ch=0;ch<s->nb_channels;ch++) {

  2260.             g = &granules[ch][gr];

  2261. 

  2262.             reorder_block(s, g);

  2263. #if defined(DEBUG)

  2264.             sample_dump(0, g->sb_hybrid, 576);

  2265. #endif

  2266.             s->compute_antialias(s, g);

  2267. #if defined(DEBUG)

  2268.             sample_dump(1, g->sb_hybrid, 576);

  2269. #endif

  2270.             compute_imdct(s, g, &s->sb_samples[ch][18 * gr][0], s->mdct_buf[ch]);

  2271. #if defined(DEBUG)

  2272.             sample_dump(2, &s->sb_samples[ch][18 * gr][0], 576);

  2273. #endif

  2274.         }

  2275.     } /* gr */

  2276.     if(get_bits_count(&s->gb)<0)

  2277.         skip_bits_long(&s->gb, -get_bits_count(&s->gb));

  2278.     return nb_granules * 18;

  2279. }

  2280. 

  2281. static int mp_decode_frame(MPADecodeContext *s,

  2282.                            OUT_INT *samples, const uint8_t *buf, int buf_size)

  2283. {

  2284.     int i, nb_frames, ch;

  2285.     OUT_INT *samples_ptr;

  2286. 

  2287.     init_get_bits(&s->gb, buf + HEADER_SIZE, (buf_size - HEADER_SIZE)*8);

  2288. 

  2289.     /* skip error protection field */

  2290.     if (s->error_protection)

  2291.         skip_bits(&s->gb, 16);

  2292. 

  2293.     dprintf(s->avctx, "frame %d:\n", s->frame_count);

  2294.     switch(s->layer) {

  2295.     case 1:

  2296.         nb_frames = mp_decode_layer1(s);

  2297.         break;

  2298.     case 2:

  2299.         nb_frames = mp_decode_layer2(s);

  2300.         break;

  2301.     case 3:

  2302.     default:

  2303.         nb_frames = mp_decode_layer3(s);

  2304. 

  2305.         s->last_buf_size=0;

  2306.         if(s->in_gb.buffer){

  2307.             align_get_bits(&s->gb);

  2308.             i= (s->gb.size_in_bits - get_bits_count(&s->gb))>>3;

  2309.             if(i >= 0 && i <= BACKSTEP_SIZE){

  2310.                 memmove(s->last_buf, s->gb.buffer + (get_bits_count(&s->gb)>>3), i);

  2311.                 s->last_buf_size=i;

  2312.             }else

  2313.                 av_log(NULL, AV_LOG_ERROR, "invalid old backstep %d\n", i);

  2314.             s->gb= s->in_gb;

  2315.             s->in_gb.buffer= NULL;

  2316.         }

  2317. 

  2318.         align_get_bits(&s->gb);

  2319.         assert((get_bits_count(&s->gb) & 7) == 0);

  2320.         i= (s->gb.size_in_bits - get_bits_count(&s->gb))>>3;

  2321. 

  2322.         if(i<0 || i > BACKSTEP_SIZE || nb_frames<0){

  2323.             av_log(NULL, AV_LOG_ERROR, "invalid new backstep %d\n", i);

  2324.             i= FFMIN(BACKSTEP_SIZE, buf_size - HEADER_SIZE);

  2325.         }

  2326.         assert(i <= buf_size - HEADER_SIZE && i>= 0);

  2327.         memcpy(s->last_buf + s->last_buf_size, s->gb.buffer + buf_size - HEADER_SIZE - i, i);

  2328.         s->last_buf_size += i;

  2329. 

  2330.         break;

  2331.     }

  2332. #if defined(DEBUG)

  2333.     for(i=0;i<nb_frames;i++) {

  2334.         for(ch=0;ch<s->nb_channels;ch++) {

  2335.             int j;

  2336.             dprintf(s->avctx, "%d-%d:", i, ch);

  2337.             for(j=0;j<SBLIMIT;j++)

  2338.                 dprintf(s->avctx, " %0.6f", (double)s->sb_samples[ch][i][j] / FRAC_ONE);

  2339.             dprintf(s->avctx, "\n");

  2340.         }

  2341.     }

  2342. #endif

  2343.     /* apply the synthesis filter */

  2344.     for(ch=0;ch<s->nb_channels;ch++) {

  2345.         samples_ptr = samples + ch;

  2346.         for(i=0;i<nb_frames;i++) {

  2347.             ff_mpa_synth_filter(s->synth_buf[ch], &(s->synth_buf_offset[ch]),

  2348.                          window, &s->dither_state,

  2349.                          samples_ptr, s->nb_channels,

  2350.                          s->sb_samples[ch][i]);

  2351.             samples_ptr += 32 * s->nb_channels;

  2352.         }

  2353.     }

  2354. #ifdef DEBUG

  2355.     s->frame_count++;

  2356. #endif

  2357.     return nb_frames * 32 * sizeof(OUT_INT) * s->nb_channels;

  2358. }

  2359. 

  2360. static int decode_frame(AVCodecContext * avctx,

  2361.                         void *data, int *data_size,

  2362.                         uint8_t * buf, int buf_size)

  2363. {

  2364.     MPADecodeContext *s = avctx->priv_data;

  2365.     uint32_t header;

  2366.     int out_size;

  2367.     OUT_INT *out_samples = data;

  2368. 

  2369. retry:

  2370.     if(buf_size < HEADER_SIZE)

  2371.         return -1;

  2372. 

  2373.     header = AV_RB32(buf);

  2374.     if(ff_mpa_check_header(header) < 0){

  2375.         buf++;

  2376. //        buf_size--;

  2377.         av_log(avctx, AV_LOG_ERROR, "Header missing skipping one byte.\n");

  2378.         goto retry;

  2379.     }

  2380. 

  2381.     if (ff_mpegaudio_decode_header(s, header) == 1) {

  2382.         /* free format: prepare to compute frame size */

  2383.         s->frame_size = -1;

  2384.         return -1;

  2385.     }

  2386.     /* update codec info */

  2387.     avctx->channels = s->nb_channels;

  2388.     avctx->bit_rate = s->bit_rate;

  2389.     avctx->sub_id = s->layer;

  2390.     switch(s->layer) {

  2391.     case 1:

  2392.         avctx->frame_size = 384;

  2393.         break;

  2394.     case 2:

  2395.         avctx->frame_size = 1152;

  2396.         break;

  2397.     case 3:

  2398.         if (s->lsf)

  2399.             avctx->frame_size = 576;

  2400.         else

  2401.             avctx->frame_size = 1152;

  2402.         break;

  2403.     }

  2404. 

  2405.     if(s->frame_size<=0 || s->frame_size > buf_size){

  2406.         av_log(avctx, AV_LOG_ERROR, "incomplete frame\n");

  2407.         return -1;

  2408.     }else if(s->frame_size < buf_size){

  2409.         av_log(avctx, AV_LOG_ERROR, "incorrect frame size\n");

  2410.         buf_size= s->frame_size;

  2411.     }

  2412. 

  2413.     out_size = mp_decode_frame(s, out_samples, buf, buf_size);

  2414.     if(out_size>=0){

  2415.         *data_size = out_size;

  2416.         avctx->sample_rate = s->sample_rate;

  2417.         //FIXME maybe move the other codec info stuff from above here too

  2418.     }else

  2419.         av_log(avctx, AV_LOG_DEBUG, "Error while decoding MPEG audio frame.\n"); //FIXME return -1 / but also return the number of bytes consumed

  2420.     s->frame_size = 0;

  2421.     return buf_size;

  2422. }

  2423. 

  2424. static void flush(AVCodecContext *avctx){

  2425.     MPADecodeContext *s = avctx->priv_data;

  2426.     s->last_buf_size= 0;

  2427. }

  2428. 

  2429. #ifdef CONFIG_MP3ADU_DECODER

  2430. static int decode_frame_adu(AVCodecContext * avctx,

  2431.                         void *data, int *data_size,

  2432.                         uint8_t * buf, int buf_size)

  2433. {

  2434.     MPADecodeContext *s = avctx->priv_data;

  2435.     uint32_t header;

  2436.     int len, out_size;

  2437.     OUT_INT *out_samples = data;

  2438. 

  2439.     len = buf_size;

  2440. 

  2441.     // Discard too short frames

  2442.     if (buf_size < HEADER_SIZE) {

  2443.         *data_size = 0;

  2444.         return buf_size;

  2445.     }

  2446. 

  2447. 

  2448.     if (len > MPA_MAX_CODED_FRAME_SIZE)

  2449.         len = MPA_MAX_CODED_FRAME_SIZE;

  2450. 

  2451.     // Get header and restore sync word

  2452.     header = AV_RB32(buf) | 0xffe00000;

  2453. 

  2454.     if (ff_mpa_check_header(header) < 0) { // Bad header, discard frame

  2455.         *data_size = 0;

  2456.         return buf_size;

  2457.     }

  2458. 

  2459.     ff_mpegaudio_decode_header(s, header);

  2460.     /* update codec info */

  2461.     avctx->sample_rate = s->sample_rate;

  2462.     avctx->channels = s->nb_channels;

  2463.     avctx->bit_rate = s->bit_rate;

  2464.     avctx->sub_id = s->layer;

  2465. 

  2466.     avctx->frame_size=s->frame_size = len;

  2467. 

  2468.     if (avctx->parse_only) {

  2469.         out_size = buf_size;

  2470.     } else {

  2471.         out_size = mp_decode_frame(s, out_samples, buf, buf_size);

  2472.     }

  2473. 

  2474.     *data_size = out_size;

  2475.     return buf_size;

  2476. }

  2477. #endif /* CONFIG_MP3ADU_DECODER */

  2478. 

  2479. #ifdef CONFIG_MP3ON4_DECODER

  2480. /* Next 3 arrays are indexed by channel config number (passed via codecdata) */

  2481. static int mp3Frames[16] = {0,1,1,2,3,3,4,5,2};   /* number of mp3 decoder instances */

  2482. static int mp3Channels[16] = {0,1,2,3,4,5,6,8,4}; /* total output channels */

  2483. /* offsets into output buffer, assume output order is FL FR BL BR C LFE */

  2484. static int chan_offset[9][5] = {

  2485.     {0},

  2486.     {0},            // C

  2487.     {0},            // FLR

  2488.     {2,0},          // C FLR

  2489.     {2,0,3},        // C FLR BS

  2490.     {4,0,2},        // C FLR BLRS

  2491.     {4,0,2,5},      // C FLR BLRS LFE

  2492.     {4,0,2,6,5},    // C FLR BLRS BLR LFE

  2493.     {0,2}           // FLR BLRS

  2494. };

  2495. 

  2496. 

  2497. static int decode_init_mp3on4(AVCodecContext * avctx)

  2498. {

  2499.     MP3On4DecodeContext *s = avctx->priv_data;

  2500.     int i;

  2501. 

  2502.     if ((avctx->extradata_size < 2) || (avctx->extradata == NULL)) {

  2503.         av_log(avctx, AV_LOG_ERROR, "Codec extradata missing or too short.\n");

  2504.         return -1;

  2505.     }

  2506. 

  2507.     s->chan_cfg = (((unsigned char *)avctx->extradata)[1] >> 3) & 0x0f;

  2508.     s->frames = mp3Frames[s->chan_cfg];

  2509.     if(!s->frames) {

  2510.         av_log(avctx, AV_LOG_ERROR, "Invalid channel config number.\n");

  2511.         return -1;

  2512.     }

  2513.     avctx->channels = mp3Channels[s->chan_cfg];

  2514. 

  2515.     /* Init the first mp3 decoder in standard way, so that all tables get builded

  2516.      * We replace avctx->priv_data with the context of the first decoder so that

  2517.      * decode_init() does not have to be changed.

  2518.      * Other decoders will be inited here copying data from the first context

  2519.      */

  2520.     // Allocate zeroed memory for the first decoder context

  2521.     s->mp3decctx[0] = av_mallocz(sizeof(MPADecodeContext));

  2522.     // Put decoder context in place to make init_decode() happy

  2523.     avctx->priv_data = s->mp3decctx[0];

  2524.     decode_init(avctx);

  2525.     // Restore mp3on4 context pointer

  2526.     avctx->priv_data = s;

  2527.     s->mp3decctx[0]->adu_mode = 1; // Set adu mode

  2528. 

  2529.     /* Create a separate codec/context for each frame (first is already ok).

  2530.      * Each frame is 1 or 2 channels - up to 5 frames allowed

  2531.      */

  2532.     for (i = 1; i < s->frames; i++) {

  2533.         s->mp3decctx[i] = av_mallocz(sizeof(MPADecodeContext));

  2534.         s->mp3decctx[i]->compute_antialias = s->mp3decctx[0]->compute_antialias;

  2535.         s->mp3decctx[i]->adu_mode = 1;

  2536.         s->mp3decctx[i]->avctx = avctx;

  2537.     }

  2538. 

  2539.     return 0;

  2540. }

  2541. 

  2542. 

  2543. static int decode_close_mp3on4(AVCodecContext * avctx)

  2544. {

  2545.     MP3On4DecodeContext *s = avctx->priv_data;

  2546.     int i;

  2547. 

  2548.     for (i = 0; i < s->frames; i++)

  2549.         if (s->mp3decctx[i])

  2550.             av_free(s->mp3decctx[i]);

  2551. 

  2552.     return 0;

  2553. }

  2554. 

  2555. 

  2556. static int decode_frame_mp3on4(AVCodecContext * avctx,

  2557.                         void *data, int *data_size,

  2558.                         uint8_t * buf, int buf_size)

  2559. {

  2560.     MP3On4DecodeContext *s = avctx->priv_data;

  2561.     MPADecodeContext *m;

  2562.     int len, out_size = 0;

  2563.     uint32_t header;

  2564.     OUT_INT *out_samples = data;

  2565.     OUT_INT decoded_buf[MPA_FRAME_SIZE * MPA_MAX_CHANNELS];

  2566.     OUT_INT *outptr, *bp;

  2567.     int fsize;

  2568.     unsigned char *start2 = buf, *start;

  2569.     int fr, i, j, n;

  2570.     int off = avctx->channels;

  2571.     int *coff = chan_offset[s->chan_cfg];

  2572. 

  2573.     len = buf_size;

  2574. 

  2575.     // Discard too short frames

  2576.     if (buf_size < HEADER_SIZE) {

  2577.         *data_size = 0;

  2578.         return buf_size;

  2579.     }

  2580. 

  2581.     // If only one decoder interleave is not needed

  2582.     outptr = s->frames == 1 ? out_samples : decoded_buf;

  2583. 

  2584.     for (fr = 0; fr < s->frames; fr++) {

  2585.         start = start2;

  2586.         fsize = (start[0] << 4) | (start[1] >> 4);

  2587.         start2 += fsize;

  2588.         if (fsize > len)

  2589.             fsize = len;

  2590.         len -= fsize;

  2591.         if (fsize > MPA_MAX_CODED_FRAME_SIZE)

  2592.             fsize = MPA_MAX_CODED_FRAME_SIZE;

  2593.         m = s->mp3decctx[fr];

  2594.         assert (m != NULL);

  2595. 

  2596.         // Get header

  2597.         header = AV_RB32(start) | 0xfff00000;

  2598. 

  2599.         if (ff_mpa_check_header(header) < 0) { // Bad header, discard block

  2600.             *data_size = 0;

  2601.             return buf_size;

  2602.         }

  2603. 

  2604.         ff_mpegaudio_decode_header(m, header);

  2605.         mp_decode_frame(m, decoded_buf, start, fsize);

  2606. 

  2607.         n = MPA_FRAME_SIZE * m->nb_channels;

  2608.         out_size += n * sizeof(OUT_INT);

  2609.         if(s->frames > 1) {

  2610.             /* interleave output data */

  2611.             bp = out_samples + coff[fr];

  2612.             if(m->nb_channels == 1) {

  2613.                 for(j = 0; j < n; j++) {

  2614.                     *bp = decoded_buf[j];

  2615.                     bp += off;

  2616.                 }

  2617.             } else {

  2618.                 for(j = 0; j < n; j++) {

  2619.                     bp[0] = decoded_buf[j++];

  2620.                     bp[1] = decoded_buf[j];

  2621.                     bp += off;

  2622.                 }

  2623.             }

  2624.         }

  2625.     }

  2626. 

  2627.     /* update codec info */

  2628.     avctx->sample_rate = s->mp3decctx[0]->sample_rate;

  2629.     avctx->frame_size= buf_size;

  2630.     avctx->bit_rate = 0;

  2631.     for (i = 0; i < s->frames; i++)

  2632.         avctx->bit_rate += s->mp3decctx[i]->bit_rate;

  2633. 

  2634.     *data_size = out_size;

  2635.     return buf_size;

  2636. }

  2637. #endif /* CONFIG_MP3ON4_DECODER */

  2638. 

  2639. #ifdef CONFIG_MP2_DECODER

  2640. AVCodec mp2_decoder =

  2641. {

  2642.     "mp2",

  2643.     CODEC_TYPE_AUDIO,

  2644.     CODEC_ID_MP2,

  2645.     sizeof(MPADecodeContext),

  2646.     decode_init,

  2647.     NULL,

  2648.     NULL,

  2649.     decode_frame,

  2650.     CODEC_CAP_PARSE_ONLY,

  2651. };

  2652. #endif

  2653. #ifdef CONFIG_MP3_DECODER

  2654. AVCodec mp3_decoder =

  2655. {

  2656.     "mp3",

  2657.     CODEC_TYPE_AUDIO,

  2658.     CODEC_ID_MP3,

  2659.     sizeof(MPADecodeContext),

  2660.     decode_init,

  2661.     NULL,

  2662.     NULL,

  2663.     decode_frame,

  2664.     CODEC_CAP_PARSE_ONLY,

  2665.     .flush= flush,

  2666. };

  2667. #endif

  2668. #ifdef CONFIG_MP3ADU_DECODER

  2669. AVCodec mp3adu_decoder =

  2670. {

  2671.     "mp3adu",

  2672.     CODEC_TYPE_AUDIO,

  2673.     CODEC_ID_MP3ADU,

  2674.     sizeof(MPADecodeContext),

  2675.     decode_init,

  2676.     NULL,

  2677.     NULL,

  2678.     decode_frame_adu,

  2679.     CODEC_CAP_PARSE_ONLY,

  2680.     .flush= flush,

  2681. };

  2682. #endif

  2683. #ifdef CONFIG_MP3ON4_DECODER

  2684. AVCodec mp3on4_decoder =

  2685. {

  2686.     "mp3on4",

  2687.     CODEC_TYPE_AUDIO,

  2688.     CODEC_ID_MP3ON4,

  2689.     sizeof(MP3On4DecodeContext),

  2690.     decode_init_mp3on4,

  2691.     NULL,

  2692.     decode_close_mp3on4,

  2693.     decode_frame_mp3on4,

  2694.     .flush= flush,

  2695. };

  2696. #endif