falkTX
/
FFmpeg
mirror of https://github.com/falkTX/FFmpeg.git
1
0
Fork 0
Code Issues 0 Releases 338 Wiki Activity
You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
4254 Commits
32 Branches
283MB
Tree: 738386a5ed
Branches Tags
${ item.name }
Create branch ${ searchTerm }
from '738386a5ed'
${ noResults }
FFmpeg/libavcodec/mpegaudiodec.c

2905 lines
86KB
Raw Blame History 

  1. /*

  2.  * MPEG Audio decoder

  3.  * Copyright (c) 2001, 2002 Fabrice Bellard.

  4.  *

  5.  * This library is free software; you can redistribute it and/or

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

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

  8.  * version 2 of the License, or (at your option) any later version.

  9.  *

  10.  * This library is distributed in the hope that it will be useful,

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

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

  13.  * Lesser General Public License for more details.

  14.  *

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

  16.  * License along with this library; if not, write to the Free Software

  17.  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

  18.  */

  19. 

  20. /**

  21.  * @file mpegaudiodec.c

  22.  * MPEG Audio decoder.

  23.  */ 

  24. 

  25. //#define DEBUG

  26. #include "avcodec.h"

  27. #include "bitstream.h"

  28. #include "mpegaudio.h"

  29. #include "dsputil.h"

  30. 

  31. /*

  32.  * TODO:

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

  34.  *  - test lsf / mpeg25 extensively.

  35.  */

  36. 

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

  38.    audio decoder */

  39. #ifdef CONFIG_MPEGAUDIO_HP

  40. #define USE_HIGHPRECISION

  41. #endif

  42. 

  43. #ifdef USE_HIGHPRECISION

  44. #define FRAC_BITS   23   /* fractional bits for sb_samples and dct */

  45. #define WFRAC_BITS  16   /* fractional bits for window */

  46. #else

  47. #define FRAC_BITS   15   /* fractional bits for sb_samples and dct */

  48. #define WFRAC_BITS  14   /* fractional bits for window */

  49. #endif

  50. 

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

  52. typedef int32_t OUT_INT;

  53. #define OUT_MAX INT32_MAX

  54. #define OUT_MIN INT32_MIN

  55. #define OUT_SHIFT (WFRAC_BITS + FRAC_BITS - 31)

  56. #else

  57. typedef int16_t OUT_INT;

  58. #define OUT_MAX INT16_MAX

  59. #define OUT_MIN INT16_MIN

  60. #define OUT_SHIFT (WFRAC_BITS + FRAC_BITS - 15)

  61. #endif

  62. 

  63. #define FRAC_ONE    (1 << FRAC_BITS)

  64. 

  65. #define MULL(a,b) (((int64_t)(a) * (int64_t)(b)) >> FRAC_BITS)

  66. #define MUL64(a,b) ((int64_t)(a) * (int64_t)(b))

  67. #define FIX(a)   ((int)((a) * FRAC_ONE))

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

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

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

  71. 

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

  73. //#define MULH(a,b) (((int64_t)(a) * (int64_t)(b))>>32) //gcc 3.4 creates an incredibly bloated mess out of this

  74. static always_inline int MULH(int a, int b){

  75.     return ((int64_t)(a) * (int64_t)(b))>>32;

  76. }

  77. 

  78. #if FRAC_BITS <= 15

  79. typedef int16_t MPA_INT;

  80. #else

  81. typedef int32_t MPA_INT;

  82. #endif

  83. 

  84. /****************/

  85. 

  86. #define HEADER_SIZE 4

  87. #define BACKSTEP_SIZE 512

  88. 

  89. struct GranuleDef;

  90. 

  91. typedef struct MPADecodeContext {

  92.     uint8_t inbuf1[2][MPA_MAX_CODED_FRAME_SIZE + BACKSTEP_SIZE];	/* input buffer */

  93.     int inbuf_index;

  94.     uint8_t *inbuf_ptr, *inbuf;

  95.     int frame_size;

  96.     int free_format_frame_size; /* frame size in case of free format

  97.                                    (zero if currently unknown) */

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

  99.     uint32_t free_format_next_header; 

  100.     int error_protection;

  101.     int layer;

  102.     int sample_rate;

  103.     int sample_rate_index; /* between 0 and 8 */

  104.     int bit_rate;

  105.     int old_frame_size;

  106.     GetBitContext gb;

  107.     int nb_channels;

  108.     int mode;

  109.     int mode_ext;

  110.     int lsf;

  111.     MPA_INT synth_buf[MPA_MAX_CHANNELS][512 * 2] __attribute__((aligned(16)));

  112.     int synth_buf_offset[MPA_MAX_CHANNELS];

  113.     int32_t sb_samples[MPA_MAX_CHANNELS][36][SBLIMIT] __attribute__((aligned(16)));

  114.     int32_t mdct_buf[MPA_MAX_CHANNELS][SBLIMIT * 18]; /* previous samples, for layer 3 MDCT */

  115. #ifdef DEBUG

  116.     int frame_count;

  117. #endif

  118.     void (*compute_antialias)(struct MPADecodeContext *s, struct GranuleDef *g);

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

  120.     unsigned int dither_state;

  121. } MPADecodeContext;

  122. 

  123. /**

  124.  * Context for MP3On4 decoder

  125.  */

  126. typedef struct MP3On4DecodeContext {

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

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

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

  130. } MP3On4DecodeContext;

  131. 

  132. /* layer 3 "granule" */

  133. typedef struct GranuleDef {

  134.     uint8_t scfsi;

  135.     int part2_3_length;

  136.     int big_values;

  137.     int global_gain;

  138.     int scalefac_compress;

  139.     uint8_t block_type;

  140.     uint8_t switch_point;

  141.     int table_select[3];

  142.     int subblock_gain[3];

  143.     uint8_t scalefac_scale;

  144.     uint8_t count1table_select;

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

  146.     int preflag;

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

  148.     uint8_t scale_factors[40];

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

  150. } GranuleDef;

  151. 

  152. #define MODE_EXT_MS_STEREO 2

  153. #define MODE_EXT_I_STEREO  1

  154. 

  155. /* layer 3 huffman tables */

  156. typedef struct HuffTable {

  157.     int xsize;

  158.     const uint8_t *bits;

  159.     const uint16_t *codes;

  160. } HuffTable;

  161. 

  162. #include "mpegaudiodectab.h"

  163. 

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

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

  166. 

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

  168. static VLC huff_vlc[16]; 

  169. static uint8_t *huff_code_table[16];

  170. static VLC huff_quad_vlc[2];

  171. /* computed from band_size_long */

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

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

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

  175. static int8_t  *table_4_3_exp;

  176. static uint32_t *table_4_3_value;

  177. /* intensity stereo coef table */

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

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

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

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

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

  183. 

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

  185. static uint16_t scale_factor_modshift[64];

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

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

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

  189. 

  190. #define SCALE_GEN(v) \

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

  192. 

  193. static int32_t scale_factor_mult2[3][3] = {

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

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

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

  197. };

  198. 

  199. void ff_mpa_synth_init(MPA_INT *window);

  200. static MPA_INT window[512] __attribute__((aligned(16)));

  201.     

  202. /* layer 1 unscaling */

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

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

  205. {

  206.     int shift, mod;

  207.     int64_t val;

  208. 

  209.     shift = scale_factor_modshift[scale_factor];

  210.     mod = shift & 3;

  211.     shift >>= 2;

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

  213.     shift += n;

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

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

  216. }

  217. 

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

  219. {

  220.     int shift, mod, val;

  221. 

  222.     shift = scale_factor_modshift[scale_factor];

  223.     mod = shift & 3;

  224.     shift >>= 2;

  225. 

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

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

  228.     if (shift > 0)

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

  230.     return val;

  231. }

  232. 

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

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

  235. {

  236.     unsigned int m;

  237.     int e;

  238. 

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

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

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

  242.     assert(e>=1);

  243.     if (e > 31)

  244.         return 0;

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

  246. 

  247.     return m;

  248. }

  249. 

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

  251. #define DEV_ORDER 13

  252. 

  253. #define POW_FRAC_BITS 24

  254. #define POW_FRAC_ONE    (1 << POW_FRAC_BITS)

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

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

  257. 

  258. static int dev_4_3_coefs[DEV_ORDER];

  259. 

  260. static int pow_mult3[3] = {

  261.     POW_FIX(1.0),

  262.     POW_FIX(1.25992104989487316476),

  263.     POW_FIX(1.58740105196819947474),

  264. };

  265. 

  266. static void int_pow_init(void)

  267. {

  268.     int i, a;

  269. 

  270.     a = POW_FIX(1.0);

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

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

  273.         dev_4_3_coefs[i] = a;

  274.     }

  275. }

  276. 

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

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

  279. {

  280.     int e, er, eq, j;

  281.     int a, a1;

  282.     

  283.     /* renormalize */

  284.     a = i;

  285.     e = POW_FRAC_BITS;

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

  287.         a = a << 1;

  288.         e--;

  289.     }

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

  291.     a1 = 0;

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

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

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

  295.     /* exponent compute (exact) */

  296.     e = e * 4;

  297.     er = e % 3;

  298.     eq = e / 3;

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

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

  301.         a = a >> 1;

  302.         eq++;

  303.     }

  304.     /* convert to float */

  305.     while (a < POW_FRAC_ONE) {

  306.         a = a << 1;

  307.         eq--;

  308.     }

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

  310. #if POW_FRAC_BITS > FRAC_BITS

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

  312.     /* correct overflow */

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

  314.         a = a >> 1;

  315.         eq++;

  316.     }

  317. #endif

  318.     *exp_ptr = eq;

  319.     return a;

  320. }

  321. 

  322. static int decode_init(AVCodecContext * avctx)

  323. {

  324.     MPADecodeContext *s = avctx->priv_data;

  325.     static int init=0;

  326.     int i, j, k;

  327. 

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

  329.     avctx->sample_fmt= SAMPLE_FMT_S32;

  330. #else

  331.     avctx->sample_fmt= SAMPLE_FMT_S16;

  332. #endif    

  333.     

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

  335.         s->compute_antialias= compute_antialias_integer;

  336.     else

  337.         s->compute_antialias= compute_antialias_float;

  338. 

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

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

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

  342.             int shift, mod;

  343.             /* 1.0 (i = 3) is normalized to 2 ^ FRAC_BITS */

  344.             shift = (i / 3);

  345.             mod = i % 3;

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

  347.         }

  348. 

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

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

  351.             int n, norm;

  352.             n = i + 2;

  353.             norm = ((int64_t_C(1) << n) * FRAC_ONE) / ((1 << n) - 1);

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

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

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

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

  358.                     i, norm, 

  359.                     scale_factor_mult[i][0],

  360.                     scale_factor_mult[i][1],

  361.                     scale_factor_mult[i][2]);

  362.         }

  363.         

  364. 	ff_mpa_synth_init(window);

  365.         

  366.         /* huffman decode tables */

  367.         huff_code_table[0] = NULL;

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

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

  370. 	    int xsize, x, y;

  371.             unsigned int n;

  372.             uint8_t *code_table;

  373. 

  374.             xsize = h->xsize;

  375.             n = xsize * xsize;

  376.             /* XXX: fail test */

  377.             init_vlc(&huff_vlc[i], 8, n, 

  378.                      h->bits, 1, 1, h->codes, 2, 2, 1);

  379.             

  380.             code_table = av_mallocz(n);

  381.             j = 0;

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

  383.                 for(y=0;y<xsize;y++)

  384.                     code_table[j++] = (x << 4) | y;

  385.             }

  386.             huff_code_table[i] = code_table;

  387.         }

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

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

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

  391.         }

  392. 

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

  394.             k = 0;

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

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

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

  398.             }

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

  400.         }

  401. 

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

  403. 	table_4_3_exp= av_mallocz_static(TABLE_4_3_SIZE * sizeof(table_4_3_exp[0]));

  404.         if(!table_4_3_exp)

  405. 	    return -1;

  406. 	table_4_3_value= av_mallocz_static(TABLE_4_3_SIZE * sizeof(table_4_3_value[0]));

  407.         if(!table_4_3_value)

  408.             return -1;

  409.         

  410.         int_pow_init();

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

  412.             double f, fm;

  413.             int e, m;

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

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

  416.             m = FIXHR(fm*0.5);

  417.             e+= FRAC_BITS - 31 + 5;

  418. 

  419.             /* normalized to FRAC_BITS */

  420.             table_4_3_value[i] = m;

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

  422.             table_4_3_exp[i] = -e;

  423.         }

  424.         

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

  426.             float f;

  427.             int v;

  428.             if (i != 6) {

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

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

  431.             } else {

  432.                 v = FIXR(1.0);

  433.             }

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

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

  436.         }

  437.         /* invalid values */

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

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

  440. 

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

  442.             double f;

  443.             int e, k;

  444. 

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

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

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

  448.                 k = i & 1;

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

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

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

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

  453.             }

  454.         }

  455. 

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

  457.             float ci, cs, ca;

  458.             ci = ci_table[i];

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

  460.             ca = cs * ci;

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

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

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

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

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

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

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

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

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

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

  471.         }

  472. 

  473.         /* compute mdct windows */

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

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

  476.                 double d;

  477.                 

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

  479.                     continue;

  480.                 

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

  482.                 if(j==1){

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

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

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

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

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

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

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

  490.                 }

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

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

  493. 

  494.                 if(j==2)

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

  496.                 else

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

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

  499.             }

  500.         }

  501. 

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

  503.            the sign of the right window coefs */

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

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

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

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

  508.             }

  509.         }

  510. 

  511. #if defined(DEBUG)

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

  513.             printf("win%d=\n", j);

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

  515.                 printf("%f, ", (double)mdct_win[j][i] / FRAC_ONE);

  516.             printf("\n");

  517.         }

  518. #endif

  519.         init = 1;

  520.     }

  521. 

  522.     s->inbuf_index = 0;

  523.     s->inbuf = &s->inbuf1[s->inbuf_index][BACKSTEP_SIZE];

  524.     s->inbuf_ptr = s->inbuf;

  525. #ifdef DEBUG

  526.     s->frame_count = 0;

  527. #endif

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

  529.         s->adu_mode = 1;

  530.     return 0;

  531. }

  532. 

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

  534. 

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

  536. 

  537. #define COS0_0  FIXR(0.50060299823519630134)

  538. #define COS0_1  FIXR(0.50547095989754365998)

  539. #define COS0_2  FIXR(0.51544730992262454697)

  540. #define COS0_3  FIXR(0.53104259108978417447)

  541. #define COS0_4  FIXR(0.55310389603444452782)

  542. #define COS0_5  FIXR(0.58293496820613387367)

  543. #define COS0_6  FIXR(0.62250412303566481615)

  544. #define COS0_7  FIXR(0.67480834145500574602)

  545. #define COS0_8  FIXR(0.74453627100229844977)

  546. #define COS0_9  FIXR(0.83934964541552703873)

  547. #define COS0_10 FIXR(0.97256823786196069369)

  548. #define COS0_11 FIXR(1.16943993343288495515)

  549. #define COS0_12 FIXR(1.48416461631416627724)

  550. #define COS0_13 FIXR(2.05778100995341155085)

  551. #define COS0_14 FIXR(3.40760841846871878570)

  552. #define COS0_15 FIXR(10.19000812354805681150)

  553. 

  554. #define COS1_0 FIXR(0.50241928618815570551)

  555. #define COS1_1 FIXR(0.52249861493968888062)

  556. #define COS1_2 FIXR(0.56694403481635770368)

  557. #define COS1_3 FIXR(0.64682178335999012954)

  558. #define COS1_4 FIXR(0.78815462345125022473)

  559. #define COS1_5 FIXR(1.06067768599034747134)

  560. #define COS1_6 FIXR(1.72244709823833392782)

  561. #define COS1_7 FIXR(5.10114861868916385802)

  562. 

  563. #define COS2_0 FIXR(0.50979557910415916894)

  564. #define COS2_1 FIXR(0.60134488693504528054)

  565. #define COS2_2 FIXR(0.89997622313641570463)

  566. #define COS2_3 FIXR(2.56291544774150617881)

  567. 

  568. #define COS3_0 FIXR(0.54119610014619698439)

  569. #define COS3_1 FIXR(1.30656296487637652785)

  570. 

  571. #define COS4_0 FIXR(0.70710678118654752439)

  572. 

  573. /* butterfly operator */

  574. #define BF(a, b, c)\

  575. {\

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

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

  578.     tab[a] = tmp0;\

  579.     tab[b] = MULL(tmp1, c);\

  580. }

  581. 

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

  583. {\

  584.     BF(a, b, COS4_0);\

  585.     BF(c, d, -COS4_0);\

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

  587. }

  588. 

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

  590. {\

  591.     BF(a, b, COS4_0);\

  592.     BF(c, d, -COS4_0);\

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

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

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

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

  597. }

  598. 

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

  600. 

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

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

  603. {

  604.     int tmp0, tmp1;

  605. 

  606.     /* pass 1 */

  607.     BF(0, 31, COS0_0);

  608.     BF(1, 30, COS0_1);

  609.     BF(2, 29, COS0_2);

  610.     BF(3, 28, COS0_3);

  611.     BF(4, 27, COS0_4);

  612.     BF(5, 26, COS0_5);

  613.     BF(6, 25, COS0_6);

  614.     BF(7, 24, COS0_7);

  615.     BF(8, 23, COS0_8);

  616.     BF(9, 22, COS0_9);

  617.     BF(10, 21, COS0_10);

  618.     BF(11, 20, COS0_11);

  619.     BF(12, 19, COS0_12);

  620.     BF(13, 18, COS0_13);

  621.     BF(14, 17, COS0_14);

  622.     BF(15, 16, COS0_15);

  623. 

  624.     /* pass 2 */

  625.     BF(0, 15, COS1_0);

  626.     BF(1, 14, COS1_1);

  627.     BF(2, 13, COS1_2);

  628.     BF(3, 12, COS1_3);

  629.     BF(4, 11, COS1_4);

  630.     BF(5, 10, COS1_5);

  631.     BF(6,  9, COS1_6);

  632.     BF(7,  8, COS1_7);

  633.     

  634.     BF(16, 31, -COS1_0);

  635.     BF(17, 30, -COS1_1);

  636.     BF(18, 29, -COS1_2);

  637.     BF(19, 28, -COS1_3);

  638.     BF(20, 27, -COS1_4);

  639.     BF(21, 26, -COS1_5);

  640.     BF(22, 25, -COS1_6);

  641.     BF(23, 24, -COS1_7);

  642.     

  643.     /* pass 3 */

  644.     BF(0, 7, COS2_0);

  645.     BF(1, 6, COS2_1);

  646.     BF(2, 5, COS2_2);

  647.     BF(3, 4, COS2_3);

  648.     

  649.     BF(8, 15, -COS2_0);

  650.     BF(9, 14, -COS2_1);

  651.     BF(10, 13, -COS2_2);

  652.     BF(11, 12, -COS2_3);

  653.     

  654.     BF(16, 23, COS2_0);

  655.     BF(17, 22, COS2_1);

  656.     BF(18, 21, COS2_2);

  657.     BF(19, 20, COS2_3);

  658.     

  659.     BF(24, 31, -COS2_0);

  660.     BF(25, 30, -COS2_1);

  661.     BF(26, 29, -COS2_2);

  662.     BF(27, 28, -COS2_3);

  663. 

  664.     /* pass 4 */

  665.     BF(0, 3, COS3_0);

  666.     BF(1, 2, COS3_1);

  667.     

  668.     BF(4, 7, -COS3_0);

  669.     BF(5, 6, -COS3_1);

  670.     

  671.     BF(8, 11, COS3_0);

  672.     BF(9, 10, COS3_1);

  673.     

  674.     BF(12, 15, -COS3_0);

  675.     BF(13, 14, -COS3_1);

  676.     

  677.     BF(16, 19, COS3_0);

  678.     BF(17, 18, COS3_1);

  679.     

  680.     BF(20, 23, -COS3_0);

  681.     BF(21, 22, -COS3_1);

  682.     

  683.     BF(24, 27, COS3_0);

  684.     BF(25, 26, COS3_1);

  685.     

  686.     BF(28, 31, -COS3_0);

  687.     BF(29, 30, -COS3_1);

  688.     

  689.     /* pass 5 */

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

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

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

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

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

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

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

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

  698.     

  699.     /* pass 6 */

  700.     

  701.     ADD( 8, 12);

  702.     ADD(12, 10);

  703.     ADD(10, 14);

  704.     ADD(14,  9);

  705.     ADD( 9, 13);

  706.     ADD(13, 11);

  707.     ADD(11, 15);

  708. 

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  725.     

  726.     ADD(24, 28);

  727.     ADD(28, 26);

  728.     ADD(26, 30);

  729.     ADD(30, 25);

  730.     ADD(25, 29);

  731.     ADD(29, 27);

  732.     ADD(27, 31);

  733. 

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  750. }

  751. 

  752. #if FRAC_BITS <= 15

  753. 

  754. static inline int round_sample(int *sum)

  755. {

  756.     int sum1;

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

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

  759.     if (sum1 < OUT_MIN)

  760.         sum1 = OUT_MIN;

  761.     else if (sum1 > OUT_MAX)

  762.         sum1 = OUT_MAX;

  763.     return sum1;

  764. }

  765. 

  766. #if defined(ARCH_POWERPC_405)

  767. 

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

  769. #define MACS(rt, ra, rb) \

  770.     asm ("maclhw %0, %2, %3" : "=r" (rt) : "0" (rt), "r" (ra), "r" (rb));

  771. 

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

  773. #define MULS(ra, rb) \

  774.     ({ int __rt; asm ("mullhw %0, %1, %2" : "=r" (__rt) : "r" (ra), "r" (rb)); __rt; })

  775. 

  776. #else

  777. 

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

  779. #define MACS(rt, ra, rb) rt += (ra) * (rb)

  780. 

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

  782. #define MULS(ra, rb) ((ra) * (rb))

  783. 

  784. #endif

  785. 

  786. #else

  787. 

  788. static inline int round_sample(int64_t *sum) 

  789. {

  790.     int sum1;

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

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

  793.     if (sum1 < OUT_MIN)

  794.         sum1 = OUT_MIN;

  795.     else if (sum1 > OUT_MAX)

  796.         sum1 = OUT_MAX;

  797.     return sum1;

  798. }

  799. 

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

  801. 

  802. #endif

  803. 

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

  805. {                                               \

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

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

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

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

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

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

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

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

  814. }

  815. 

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

  817. {                                               \

  818.     int tmp;\

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  843. }

  844. 

  845. void ff_mpa_synth_init(MPA_INT *window)

  846. {

  847.     int i;

  848. 

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

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

  851.         int v;

  852.         v = mpa_enwindow[i];

  853. #if WFRAC_BITS < 16

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

  855. #endif

  856.         window[i] = v;

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

  858.             v = -v;

  859.         if (i != 0)

  860.             window[512 - i] = v;

  861.     }	

  862. }

  863. 

  864. /* 32 sub band synthesis filter. Input: 32 sub band samples, Output:

  865.    32 samples. */

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

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

  868. 			 MPA_INT *window, int *dither_state,

  869.                          OUT_INT *samples, int incr, 

  870.                          int32_t sb_samples[SBLIMIT])

  871. {

  872.     int32_t tmp[32];

  873.     register MPA_INT *synth_buf;

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

  875.     int j, offset, v;

  876.     OUT_INT *samples2;

  877. #if FRAC_BITS <= 15

  878.     int sum, sum2;

  879. #else

  880.     int64_t sum, sum2;

  881. #endif

  882. 

  883.     dct32(tmp, sb_samples);

  884.     

  885.     offset = *synth_buf_offset;

  886.     synth_buf = synth_buf_ptr + offset;

  887. 

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

  889.         v = tmp[j];

  890. #if FRAC_BITS <= 15

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

  892.            sound */

  893.         if (v > 32767)

  894.             v = 32767;

  895.         else if (v < -32768)

  896.             v = -32768;

  897. #endif

  898.         synth_buf[j] = v;

  899.     }

  900.     /* copy to avoid wrap */

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

  902. 

  903.     samples2 = samples + 31 * incr;

  904.     w = window;

  905.     w2 = window + 31;

  906. 

  907.     sum = *dither_state;

  908.     p = synth_buf + 16;

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

  910.     p = synth_buf + 48;

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

  912.     *samples = round_sample(&sum);

  913.     samples += incr;

  914.     w++;

  915. 

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

  917.        access per two sample */

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

  919.         sum2 = 0;

  920.         p = synth_buf + 16 + j;

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

  922.         p = synth_buf + 48 - j;

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

  924. 

  925.         *samples = round_sample(&sum);

  926.         samples += incr;

  927.         sum += sum2;

  928.         *samples2 = round_sample(&sum);

  929.         samples2 -= incr;

  930.         w++;

  931.         w2--;

  932.     }

  933.     

  934.     p = synth_buf + 32;

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

  936.     *samples = round_sample(&sum);

  937.     *dither_state= sum;

  938. 

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

  940.     *synth_buf_offset = offset;

  941. }

  942. 

  943. #define C3 FIXHR(0.86602540378443864676/2)

  944. 

  945. /* 0.5 / cos(pi*(2*i+1)/36) */

  946. static const int icos36[9] = {

  947.     FIXR(0.50190991877167369479),

  948.     FIXR(0.51763809020504152469), //0

  949.     FIXR(0.55168895948124587824),

  950.     FIXR(0.61038729438072803416),

  951.     FIXR(0.70710678118654752439), //1

  952.     FIXR(0.87172339781054900991),

  953.     FIXR(1.18310079157624925896),

  954.     FIXR(1.93185165257813657349), //2

  955.     FIXR(5.73685662283492756461),

  956. };

  957. 

  958. /* 12 points IMDCT. We compute it "by hand" by factorizing obvious

  959.    cases. */

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

  961. {

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

  963. 

  964.     in0= in[0*3];

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

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

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

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

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

  970.     in5 += in3;

  971.     in3 += in1;

  972. 

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

  974.     in3= MULH(2*in3, C3);

  975.     

  976.     t1 = in0 - in4;

  977.     t2 = MULL(in1 - in5, icos36[4]);

  978. 

  979.     out[ 7]= 

  980.     out[10]= t1 + t2;

  981.     out[ 1]=

  982.     out[ 4]= t1 - t2;

  983. 

  984.     in0 += in4>>1;

  985.     in4 = in0 + in2;

  986.     in1 += in5>>1;

  987.     in5 = MULL(in1 + in3, icos36[1]);    

  988.     out[ 8]= 

  989.     out[ 9]= in4 + in5;

  990.     out[ 2]=

  991.     out[ 3]= in4 - in5;

  992.     

  993.     in0 -= in2;

  994.     in1 = MULL(in1 - in3, icos36[7]);

  995.     out[ 0]=

  996.     out[ 5]= in0 - in1;

  997.     out[ 6]=

  998.     out[11]= in0 + in1;    

  999. }

  1000. 

  1001. /* cos(pi*i/18) */

  1002. #define C1 FIXHR(0.98480775301220805936/2)

  1003. #define C2 FIXHR(0.93969262078590838405/2)

  1004. #define C3 FIXHR(0.86602540378443864676/2)

  1005. #define C4 FIXHR(0.76604444311897803520/2)

  1006. #define C5 FIXHR(0.64278760968653932632/2)

  1007. #define C6 FIXHR(0.5/2)

  1008. #define C7 FIXHR(0.34202014332566873304/2)

  1009. #define C8 FIXHR(0.17364817766693034885/2)

  1010. 

  1011. 

  1012. /* using Lee like decomposition followed by hand coded 9 points DCT */

  1013. static void imdct36(int *out, int *buf, int *in, int *win)

  1014. {

  1015.     int i, j, t0, t1, t2, t3, s0, s1, s2, s3;

  1016.     int tmp[18], *tmp1, *in1;

  1017. 

  1018.     for(i=17;i>=1;i--)

  1019.         in[i] += in[i-1];

  1020.     for(i=17;i>=3;i-=2)

  1021.         in[i] += in[i-2];

  1022. 

  1023.     for(j=0;j<2;j++) {

  1024.         tmp1 = tmp + j;

  1025.         in1 = in + j;

  1026. #if 0

  1027. //more accurate but slower

  1028.         int64_t t0, t1, t2, t3;

  1029.         t2 = in1[2*4] + in1[2*8] - in1[2*2];

  1030.         

  1031.         t3 = (in1[2*0] + (int64_t)(in1[2*6]>>1))<<32;

  1032.         t1 = in1[2*0] - in1[2*6];

  1033.         tmp1[ 6] = t1 - (t2>>1);

  1034.         tmp1[16] = t1 + t2;

  1035. 

  1036.         t0 = MUL64(2*(in1[2*2] + in1[2*4]),    C2);

  1037.         t1 = MUL64(   in1[2*4] - in1[2*8] , -2*C8);

  1038.         t2 = MUL64(2*(in1[2*2] + in1[2*8]),   -C4);

  1039.         

  1040.         tmp1[10] = (t3 - t0 - t2) >> 32;

  1041.         tmp1[ 2] = (t3 + t0 + t1) >> 32;

  1042.         tmp1[14] = (t3 + t2 - t1) >> 32;

  1043.         

  1044.         tmp1[ 4] = MULH(2*(in1[2*5] + in1[2*7] - in1[2*1]), -C3);

  1045.         t2 = MUL64(2*(in1[2*1] + in1[2*5]),    C1);

  1046.         t3 = MUL64(   in1[2*5] - in1[2*7] , -2*C7);

  1047.         t0 = MUL64(2*in1[2*3], C3);

  1048. 

  1049.         t1 = MUL64(2*(in1[2*1] + in1[2*7]),   -C5);

  1050. 

  1051.         tmp1[ 0] = (t2 + t3 + t0) >> 32;

  1052.         tmp1[12] = (t2 + t1 - t0) >> 32;

  1053.         tmp1[ 8] = (t3 - t1 - t0) >> 32;

  1054. #else

  1055.         t2 = in1[2*4] + in1[2*8] - in1[2*2];

  1056.         

  1057.         t3 = in1[2*0] + (in1[2*6]>>1);

  1058.         t1 = in1[2*0] - in1[2*6];

  1059.         tmp1[ 6] = t1 - (t2>>1);

  1060.         tmp1[16] = t1 + t2;

  1061. 

  1062.         t0 = MULH(2*(in1[2*2] + in1[2*4]),    C2);

  1063.         t1 = MULH(   in1[2*4] - in1[2*8] , -2*C8);

  1064.         t2 = MULH(2*(in1[2*2] + in1[2*8]),   -C4);

  1065.         

  1066.         tmp1[10] = t3 - t0 - t2;

  1067.         tmp1[ 2] = t3 + t0 + t1;

  1068.         tmp1[14] = t3 + t2 - t1;

  1069.         

  1070.         tmp1[ 4] = MULH(2*(in1[2*5] + in1[2*7] - in1[2*1]), -C3);

  1071.         t2 = MULH(2*(in1[2*1] + in1[2*5]),    C1);

  1072.         t3 = MULH(   in1[2*5] - in1[2*7] , -2*C7);

  1073.         t0 = MULH(2*in1[2*3], C3);

  1074. 

  1075.         t1 = MULH(2*(in1[2*1] + in1[2*7]),   -C5);

  1076. 

  1077.         tmp1[ 0] = t2 + t3 + t0;

  1078.         tmp1[12] = t2 + t1 - t0;

  1079.         tmp1[ 8] = t3 - t1 - t0;

  1080. #endif

  1081.     }

  1082. 

  1083.     i = 0;

  1084.     for(j=0;j<4;j++) {

  1085.         t0 = tmp[i];

  1086.         t1 = tmp[i + 2];

  1087.         s0 = t1 + t0;

  1088.         s2 = t1 - t0;

  1089. 

  1090.         t2 = tmp[i + 1];

  1091.         t3 = tmp[i + 3];

  1092.         s1 = MULL(t3 + t2, icos36[j]);

  1093.         s3 = MULL(t3 - t2, icos36[8 - j]);

  1094.         

  1095.         t0 = s0 + s1;

  1096.         t1 = s0 - s1;

  1097.         out[(9 + j)*SBLIMIT] =  MULH(t1, win[9 + j]) + buf[9 + j];

  1098.         out[(8 - j)*SBLIMIT] =  MULH(t1, win[8 - j]) + buf[8 - j];

  1099.         buf[9 + j] = MULH(t0, win[18 + 9 + j]);

  1100.         buf[8 - j] = MULH(t0, win[18 + 8 - j]);

  1101.         

  1102.         t0 = s2 + s3;

  1103.         t1 = s2 - s3;

  1104.         out[(9 + 8 - j)*SBLIMIT] =  MULH(t1, win[9 + 8 - j]) + buf[9 + 8 - j];

  1105.         out[(        j)*SBLIMIT] =  MULH(t1, win[        j]) + buf[        j];

  1106.         buf[9 + 8 - j] = MULH(t0, win[18 + 9 + 8 - j]);

  1107.         buf[      + j] = MULH(t0, win[18         + j]);

  1108.         i += 4;

  1109.     }

  1110. 

  1111.     s0 = tmp[16];

  1112.     s1 = MULL(tmp[17], icos36[4]);

  1113.     t0 = s0 + s1;

  1114.     t1 = s0 - s1;

  1115.     out[(9 + 4)*SBLIMIT] =  MULH(t1, win[9 + 4]) + buf[9 + 4];

  1116.     out[(8 - 4)*SBLIMIT] =  MULH(t1, win[8 - 4]) + buf[8 - 4];

  1117.     buf[9 + 4] = MULH(t0, win[18 + 9 + 4]);

  1118.     buf[8 - 4] = MULH(t0, win[18 + 8 - 4]);

  1119. }

  1120. 

  1121. /* header decoding. MUST check the header before because no

  1122.    consistency check is done there. Return 1 if free format found and

  1123.    that the frame size must be computed externally */

  1124. static int decode_header(MPADecodeContext *s, uint32_t header)

  1125. {

  1126.     int sample_rate, frame_size, mpeg25, padding;

  1127.     int sample_rate_index, bitrate_index;

  1128.     if (header & (1<<20)) {

  1129.         s->lsf = (header & (1<<19)) ? 0 : 1;

  1130.         mpeg25 = 0;

  1131.     } else {

  1132.         s->lsf = 1;

  1133.         mpeg25 = 1;

  1134.     }

  1135.     

  1136.     s->layer = 4 - ((header >> 17) & 3);

  1137.     /* extract frequency */

  1138.     sample_rate_index = (header >> 10) & 3;

  1139.     sample_rate = mpa_freq_tab[sample_rate_index] >> (s->lsf + mpeg25);

  1140.     sample_rate_index += 3 * (s->lsf + mpeg25);

  1141.     s->sample_rate_index = sample_rate_index;

  1142.     s->error_protection = ((header >> 16) & 1) ^ 1;

  1143.     s->sample_rate = sample_rate;

  1144. 

  1145.     bitrate_index = (header >> 12) & 0xf;

  1146.     padding = (header >> 9) & 1;

  1147.     //extension = (header >> 8) & 1;

  1148.     s->mode = (header >> 6) & 3;

  1149.     s->mode_ext = (header >> 4) & 3;

  1150.     //copyright = (header >> 3) & 1;

  1151.     //original = (header >> 2) & 1;

  1152.     //emphasis = header & 3;

  1153. 

  1154.     if (s->mode == MPA_MONO)

  1155.         s->nb_channels = 1;

  1156.     else

  1157.         s->nb_channels = 2;

  1158.     

  1159.     if (bitrate_index != 0) {

  1160.         frame_size = mpa_bitrate_tab[s->lsf][s->layer - 1][bitrate_index];

  1161.         s->bit_rate = frame_size * 1000;

  1162.         switch(s->layer) {

  1163.         case 1:

  1164.             frame_size = (frame_size * 12000) / sample_rate;

  1165.             frame_size = (frame_size + padding) * 4;

  1166.             break;

  1167.         case 2:

  1168.             frame_size = (frame_size * 144000) / sample_rate;

  1169.             frame_size += padding;

  1170.             break;

  1171.         default:

  1172.         case 3:

  1173.             frame_size = (frame_size * 144000) / (sample_rate << s->lsf);

  1174.             frame_size += padding;

  1175.             break;

  1176.         }

  1177.         s->frame_size = frame_size;

  1178.     } else {

  1179.         /* if no frame size computed, signal it */

  1180.         if (!s->free_format_frame_size)

  1181.             return 1;

  1182.         /* free format: compute bitrate and real frame size from the

  1183.            frame size we extracted by reading the bitstream */

  1184.         s->frame_size = s->free_format_frame_size;

  1185.         switch(s->layer) {

  1186.         case 1:

  1187.             s->frame_size += padding  * 4;

  1188.             s->bit_rate = (s->frame_size * sample_rate) / 48000;

  1189.             break;

  1190.         case 2:

  1191.             s->frame_size += padding;

  1192.             s->bit_rate = (s->frame_size * sample_rate) / 144000;

  1193.             break;

  1194.         default:

  1195.         case 3:

  1196.             s->frame_size += padding;

  1197.             s->bit_rate = (s->frame_size * (sample_rate << s->lsf)) / 144000;

  1198.             break;

  1199.         }

  1200.     }

  1201.     

  1202. #if defined(DEBUG)

  1203.     printf("layer%d, %d Hz, %d kbits/s, ",

  1204.            s->layer, s->sample_rate, s->bit_rate);

  1205.     if (s->nb_channels == 2) {

  1206.         if (s->layer == 3) {

  1207.             if (s->mode_ext & MODE_EXT_MS_STEREO)

  1208.                 printf("ms-");

  1209.             if (s->mode_ext & MODE_EXT_I_STEREO)

  1210.                 printf("i-");

  1211.         }

  1212.         printf("stereo");

  1213.     } else {

  1214.         printf("mono");

  1215.     }

  1216.     printf("\n");

  1217. #endif

  1218.     return 0;

  1219. }

  1220. 

  1221. /* useful helper to get mpeg audio stream infos. Return -1 if error in

  1222.    header, otherwise the coded frame size in bytes */

  1223. int mpa_decode_header(AVCodecContext *avctx, uint32_t head)

  1224. {

  1225.     MPADecodeContext s1, *s = &s1;

  1226.     memset( s, 0, sizeof(MPADecodeContext) );

  1227. 

  1228.     if (ff_mpa_check_header(head) != 0)

  1229.         return -1;

  1230. 

  1231.     if (decode_header(s, head) != 0) {

  1232.         return -1;

  1233.     }

  1234. 

  1235.     switch(s->layer) {

  1236.     case 1:

  1237.         avctx->frame_size = 384;

  1238.         break;

  1239.     case 2:

  1240.         avctx->frame_size = 1152;

  1241.         break;

  1242.     default:

  1243.     case 3:

  1244.         if (s->lsf)

  1245.             avctx->frame_size = 576;

  1246.         else

  1247.             avctx->frame_size = 1152;

  1248.         break;

  1249.     }

  1250. 

  1251.     avctx->sample_rate = s->sample_rate;

  1252.     avctx->channels = s->nb_channels;

  1253.     avctx->bit_rate = s->bit_rate;

  1254.     avctx->sub_id = s->layer;

  1255.     return s->frame_size;

  1256. }

  1257. 

  1258. /* return the number of decoded frames */

  1259. static int mp_decode_layer1(MPADecodeContext *s)

  1260. {

  1261.     int bound, i, v, n, ch, j, mant;

  1262.     uint8_t allocation[MPA_MAX_CHANNELS][SBLIMIT];

  1263.     uint8_t scale_factors[MPA_MAX_CHANNELS][SBLIMIT];

  1264. 

  1265.     if (s->mode == MPA_JSTEREO) 

  1266.         bound = (s->mode_ext + 1) * 4;

  1267.     else

  1268.         bound = SBLIMIT;

  1269. 

  1270.     /* allocation bits */

  1271.     for(i=0;i<bound;i++) {

  1272.         for(ch=0;ch<s->nb_channels;ch++) {

  1273.             allocation[ch][i] = get_bits(&s->gb, 4);

  1274.         }

  1275.     }

  1276.     for(i=bound;i<SBLIMIT;i++) {

  1277.         allocation[0][i] = get_bits(&s->gb, 4);

  1278.     }

  1279. 

  1280.     /* scale factors */

  1281.     for(i=0;i<bound;i++) {

  1282.         for(ch=0;ch<s->nb_channels;ch++) {

  1283.             if (allocation[ch][i])

  1284.                 scale_factors[ch][i] = get_bits(&s->gb, 6);

  1285.         }

  1286.     }

  1287.     for(i=bound;i<SBLIMIT;i++) {

  1288.         if (allocation[0][i]) {

  1289.             scale_factors[0][i] = get_bits(&s->gb, 6);

  1290.             scale_factors[1][i] = get_bits(&s->gb, 6);

  1291.         }

  1292.     }

  1293.     

  1294.     /* compute samples */

  1295.     for(j=0;j<12;j++) {

  1296.         for(i=0;i<bound;i++) {

  1297.             for(ch=0;ch<s->nb_channels;ch++) {

  1298.                 n = allocation[ch][i];

  1299.                 if (n) {

  1300.                     mant = get_bits(&s->gb, n + 1);

  1301.                     v = l1_unscale(n, mant, scale_factors[ch][i]);

  1302.                 } else {

  1303.                     v = 0;

  1304.                 }

  1305.                 s->sb_samples[ch][j][i] = v;

  1306.             }

  1307.         }

  1308.         for(i=bound;i<SBLIMIT;i++) {

  1309.             n = allocation[0][i];

  1310.             if (n) {

  1311.                 mant = get_bits(&s->gb, n + 1);

  1312.                 v = l1_unscale(n, mant, scale_factors[0][i]);

  1313.                 s->sb_samples[0][j][i] = v;

  1314.                 v = l1_unscale(n, mant, scale_factors[1][i]);

  1315.                 s->sb_samples[1][j][i] = v;

  1316.             } else {

  1317.                 s->sb_samples[0][j][i] = 0;

  1318.                 s->sb_samples[1][j][i] = 0;

  1319.             }

  1320.         }

  1321.     }

  1322.     return 12;

  1323. }

  1324. 

  1325. /* bitrate is in kb/s */

  1326. int l2_select_table(int bitrate, int nb_channels, int freq, int lsf)

  1327. {

  1328.     int ch_bitrate, table;

  1329.     

  1330.     ch_bitrate = bitrate / nb_channels;

  1331.     if (!lsf) {

  1332.         if ((freq == 48000 && ch_bitrate >= 56) ||

  1333.             (ch_bitrate >= 56 && ch_bitrate <= 80)) 

  1334.             table = 0;

  1335.         else if (freq != 48000 && ch_bitrate >= 96) 

  1336.             table = 1;

  1337.         else if (freq != 32000 && ch_bitrate <= 48) 

  1338.             table = 2;

  1339.         else 

  1340.             table = 3;

  1341.     } else {

  1342.         table = 4;

  1343.     }

  1344.     return table;

  1345. }

  1346. 

  1347. static int mp_decode_layer2(MPADecodeContext *s)

  1348. {

  1349.     int sblimit; /* number of used subbands */

  1350.     const unsigned char *alloc_table;

  1351.     int table, bit_alloc_bits, i, j, ch, bound, v;

  1352.     unsigned char bit_alloc[MPA_MAX_CHANNELS][SBLIMIT];

  1353.     unsigned char scale_code[MPA_MAX_CHANNELS][SBLIMIT];

  1354.     unsigned char scale_factors[MPA_MAX_CHANNELS][SBLIMIT][3], *sf;

  1355.     int scale, qindex, bits, steps, k, l, m, b;

  1356. 

  1357.     /* select decoding table */

  1358.     table = l2_select_table(s->bit_rate / 1000, s->nb_channels, 

  1359.                             s->sample_rate, s->lsf);

  1360.     sblimit = sblimit_table[table];

  1361.     alloc_table = alloc_tables[table];

  1362. 

  1363.     if (s->mode == MPA_JSTEREO) 

  1364.         bound = (s->mode_ext + 1) * 4;

  1365.     else

  1366.         bound = sblimit;

  1367. 

  1368.     dprintf("bound=%d sblimit=%d\n", bound, sblimit);

  1369. 

  1370.     /* sanity check */

  1371.     if( bound > sblimit ) bound = sblimit;

  1372. 

  1373.     /* parse bit allocation */

  1374.     j = 0;

  1375.     for(i=0;i<bound;i++) {

  1376.         bit_alloc_bits = alloc_table[j];

  1377.         for(ch=0;ch<s->nb_channels;ch++) {

  1378.             bit_alloc[ch][i] = get_bits(&s->gb, bit_alloc_bits);

  1379.         }

  1380.         j += 1 << bit_alloc_bits;

  1381.     }

  1382.     for(i=bound;i<sblimit;i++) {

  1383.         bit_alloc_bits = alloc_table[j];

  1384.         v = get_bits(&s->gb, bit_alloc_bits);

  1385.         bit_alloc[0][i] = v;

  1386.         bit_alloc[1][i] = v;

  1387.         j += 1 << bit_alloc_bits;

  1388.     }

  1389. 

  1390. #ifdef DEBUG

  1391.     {

  1392.         for(ch=0;ch<s->nb_channels;ch++) {

  1393.             for(i=0;i<sblimit;i++)

  1394.                 printf(" %d", bit_alloc[ch][i]);

  1395.             printf("\n");

  1396.         }

  1397.     }

  1398. #endif

  1399. 

  1400.     /* scale codes */

  1401.     for(i=0;i<sblimit;i++) {

  1402.         for(ch=0;ch<s->nb_channels;ch++) {

  1403.             if (bit_alloc[ch][i]) 

  1404.                 scale_code[ch][i] = get_bits(&s->gb, 2);

  1405.         }

  1406.     }

  1407.     

  1408.     /* scale factors */

  1409.     for(i=0;i<sblimit;i++) {

  1410.         for(ch=0;ch<s->nb_channels;ch++) {

  1411.             if (bit_alloc[ch][i]) {

  1412.                 sf = scale_factors[ch][i];

  1413.                 switch(scale_code[ch][i]) {

  1414.                 default:

  1415.                 case 0:

  1416.                     sf[0] = get_bits(&s->gb, 6);

  1417.                     sf[1] = get_bits(&s->gb, 6);

  1418.                     sf[2] = get_bits(&s->gb, 6);

  1419.                     break;

  1420.                 case 2:

  1421.                     sf[0] = get_bits(&s->gb, 6);

  1422.                     sf[1] = sf[0];

  1423.                     sf[2] = sf[0];

  1424.                     break;

  1425.                 case 1:

  1426.                     sf[0] = get_bits(&s->gb, 6);

  1427.                     sf[2] = get_bits(&s->gb, 6);

  1428.                     sf[1] = sf[0];

  1429.                     break;

  1430.                 case 3:

  1431.                     sf[0] = get_bits(&s->gb, 6);

  1432.                     sf[2] = get_bits(&s->gb, 6);

  1433.                     sf[1] = sf[2];

  1434.                     break;

  1435.                 }

  1436.             }

  1437.         }

  1438.     }

  1439. 

  1440. #ifdef DEBUG

  1441.     for(ch=0;ch<s->nb_channels;ch++) {

  1442.         for(i=0;i<sblimit;i++) {

  1443.             if (bit_alloc[ch][i]) {

  1444.                 sf = scale_factors[ch][i];

  1445.                 printf(" %d %d %d", sf[0], sf[1], sf[2]);

  1446.             } else {

  1447.                 printf(" -");

  1448.             }

  1449.         }

  1450.         printf("\n");

  1451.     }

  1452. #endif

  1453. 

  1454.     /* samples */

  1455.     for(k=0;k<3;k++) {

  1456.         for(l=0;l<12;l+=3) {

  1457.             j = 0;

  1458.             for(i=0;i<bound;i++) {

  1459.                 bit_alloc_bits = alloc_table[j];

  1460.                 for(ch=0;ch<s->nb_channels;ch++) {

  1461.                     b = bit_alloc[ch][i];

  1462.                     if (b) {

  1463.                         scale = scale_factors[ch][i][k];

  1464.                         qindex = alloc_table[j+b];

  1465.                         bits = quant_bits[qindex];

  1466.                         if (bits < 0) {

  1467.                             /* 3 values at the same time */

  1468.                             v = get_bits(&s->gb, -bits);

  1469.                             steps = quant_steps[qindex];

  1470.                             s->sb_samples[ch][k * 12 + l + 0][i] = 

  1471.                                 l2_unscale_group(steps, v % steps, scale);

  1472.                             v = v / steps;

  1473.                             s->sb_samples[ch][k * 12 + l + 1][i] = 

  1474.                                 l2_unscale_group(steps, v % steps, scale);

  1475.                             v = v / steps;

  1476.                             s->sb_samples[ch][k * 12 + l + 2][i] = 

  1477.                                 l2_unscale_group(steps, v, scale);

  1478.                         } else {

  1479.                             for(m=0;m<3;m++) {

  1480.                                 v = get_bits(&s->gb, bits);

  1481.                                 v = l1_unscale(bits - 1, v, scale);

  1482.                                 s->sb_samples[ch][k * 12 + l + m][i] = v;

  1483.                             }

  1484.                         }

  1485.                     } else {

  1486.                         s->sb_samples[ch][k * 12 + l + 0][i] = 0;

  1487.                         s->sb_samples[ch][k * 12 + l + 1][i] = 0;

  1488.                         s->sb_samples[ch][k * 12 + l + 2][i] = 0;

  1489.                     }

  1490.                 }

  1491.                 /* next subband in alloc table */

  1492.                 j += 1 << bit_alloc_bits; 

  1493.             }

  1494.             /* XXX: find a way to avoid this duplication of code */

  1495.             for(i=bound;i<sblimit;i++) {

  1496.                 bit_alloc_bits = alloc_table[j];

  1497.                 b = bit_alloc[0][i];

  1498.                 if (b) {

  1499.                     int mant, scale0, scale1;

  1500.                     scale0 = scale_factors[0][i][k];

  1501.                     scale1 = scale_factors[1][i][k];

  1502.                     qindex = alloc_table[j+b];

  1503.                     bits = quant_bits[qindex];

  1504.                     if (bits < 0) {

  1505.                         /* 3 values at the same time */

  1506.                         v = get_bits(&s->gb, -bits);

  1507.                         steps = quant_steps[qindex];

  1508.                         mant = v % steps;

  1509.                         v = v / steps;

  1510.                         s->sb_samples[0][k * 12 + l + 0][i] = 

  1511.                             l2_unscale_group(steps, mant, scale0);

  1512.                         s->sb_samples[1][k * 12 + l + 0][i] = 

  1513.                             l2_unscale_group(steps, mant, scale1);

  1514.                         mant = v % steps;

  1515.                         v = v / steps;

  1516.                         s->sb_samples[0][k * 12 + l + 1][i] = 

  1517.                             l2_unscale_group(steps, mant, scale0);

  1518.                         s->sb_samples[1][k * 12 + l + 1][i] = 

  1519.                             l2_unscale_group(steps, mant, scale1);

  1520.                         s->sb_samples[0][k * 12 + l + 2][i] = 

  1521.                             l2_unscale_group(steps, v, scale0);

  1522.                         s->sb_samples[1][k * 12 + l + 2][i] = 

  1523.                             l2_unscale_group(steps, v, scale1);

  1524.                     } else {

  1525.                         for(m=0;m<3;m++) {

  1526.                             mant = get_bits(&s->gb, bits);

  1527.                             s->sb_samples[0][k * 12 + l + m][i] = 

  1528.                                 l1_unscale(bits - 1, mant, scale0);

  1529.                             s->sb_samples[1][k * 12 + l + m][i] = 

  1530.                                 l1_unscale(bits - 1, mant, scale1);

  1531.                         }

  1532.                     }

  1533.                 } else {

  1534.                     s->sb_samples[0][k * 12 + l + 0][i] = 0;

  1535.                     s->sb_samples[0][k * 12 + l + 1][i] = 0;

  1536.                     s->sb_samples[0][k * 12 + l + 2][i] = 0;

  1537.                     s->sb_samples[1][k * 12 + l + 0][i] = 0;

  1538.                     s->sb_samples[1][k * 12 + l + 1][i] = 0;

  1539.                     s->sb_samples[1][k * 12 + l + 2][i] = 0;

  1540.                 }

  1541.                 /* next subband in alloc table */

  1542.                 j += 1 << bit_alloc_bits; 

  1543.             }

  1544.             /* fill remaining samples to zero */

  1545.             for(i=sblimit;i<SBLIMIT;i++) {

  1546.                 for(ch=0;ch<s->nb_channels;ch++) {

  1547.                     s->sb_samples[ch][k * 12 + l + 0][i] = 0;

  1548.                     s->sb_samples[ch][k * 12 + l + 1][i] = 0;

  1549.                     s->sb_samples[ch][k * 12 + l + 2][i] = 0;

  1550.                 }

  1551.             }

  1552.         }

  1553.     }

  1554.     return 3 * 12;

  1555. }

  1556. 

  1557. /*

  1558.  * Seek back in the stream for backstep bytes (at most 511 bytes)

  1559.  */

  1560. static void seek_to_maindata(MPADecodeContext *s, unsigned int backstep)

  1561. {

  1562.     uint8_t *ptr;

  1563. 

  1564.     /* compute current position in stream */

  1565.     ptr = (uint8_t *)(s->gb.buffer + (get_bits_count(&s->gb)>>3));

  1566. 

  1567.     /* copy old data before current one */

  1568.     ptr -= backstep;

  1569.     memcpy(ptr, s->inbuf1[s->inbuf_index ^ 1] + 

  1570.            BACKSTEP_SIZE + s->old_frame_size - backstep, backstep);

  1571.     /* init get bits again */

  1572.     init_get_bits(&s->gb, ptr, (s->frame_size + backstep)*8);

  1573. 

  1574.     /* prepare next buffer */

  1575.     s->inbuf_index ^= 1;

  1576.     s->inbuf = &s->inbuf1[s->inbuf_index][BACKSTEP_SIZE];

  1577.     s->old_frame_size = s->frame_size;

  1578. }

  1579. 

  1580. static inline void lsf_sf_expand(int *slen,

  1581.                                  int sf, int n1, int n2, int n3)

  1582. {

  1583.     if (n3) {

  1584.         slen[3] = sf % n3;

  1585.         sf /= n3;

  1586.     } else {

  1587.         slen[3] = 0;

  1588.     }

  1589.     if (n2) {

  1590.         slen[2] = sf % n2;

  1591.         sf /= n2;

  1592.     } else {

  1593.         slen[2] = 0;

  1594.     }

  1595.     slen[1] = sf % n1;

  1596.     sf /= n1;

  1597.     slen[0] = sf;

  1598. }

  1599. 

  1600. static void exponents_from_scale_factors(MPADecodeContext *s, 

  1601.                                          GranuleDef *g,

  1602.                                          int16_t *exponents)

  1603. {

  1604.     const uint8_t *bstab, *pretab;

  1605.     int len, i, j, k, l, v0, shift, gain, gains[3];

  1606.     int16_t *exp_ptr;

  1607. 

  1608.     exp_ptr = exponents;

  1609.     gain = g->global_gain - 210;

  1610.     shift = g->scalefac_scale + 1;

  1611. 

  1612.     bstab = band_size_long[s->sample_rate_index];

  1613.     pretab = mpa_pretab[g->preflag];

  1614.     for(i=0;i<g->long_end;i++) {

  1615.         v0 = gain - ((g->scale_factors[i] + pretab[i]) << shift);

  1616.         len = bstab[i];

  1617.         for(j=len;j>0;j--)

  1618.             *exp_ptr++ = v0;

  1619.     }

  1620. 

  1621.     if (g->short_start < 13) {

  1622.         bstab = band_size_short[s->sample_rate_index];

  1623.         gains[0] = gain - (g->subblock_gain[0] << 3);

  1624.         gains[1] = gain - (g->subblock_gain[1] << 3);

  1625.         gains[2] = gain - (g->subblock_gain[2] << 3);

  1626.         k = g->long_end;

  1627.         for(i=g->short_start;i<13;i++) {

  1628.             len = bstab[i];

  1629.             for(l=0;l<3;l++) {

  1630.                 v0 = gains[l] - (g->scale_factors[k++] << shift);

  1631.                 for(j=len;j>0;j--)

  1632.                 *exp_ptr++ = v0;

  1633.             }

  1634.         }

  1635.     }

  1636. }

  1637. 

  1638. /* handle n = 0 too */

  1639. static inline int get_bitsz(GetBitContext *s, int n)

  1640. {

  1641.     if (n == 0)

  1642.         return 0;

  1643.     else

  1644.         return get_bits(s, n);

  1645. }

  1646. 

  1647. static int huffman_decode(MPADecodeContext *s, GranuleDef *g,

  1648.                           int16_t *exponents, int end_pos)

  1649. {

  1650.     int s_index;

  1651.     int linbits, code, x, y, l, v, i, j, k, pos;

  1652.     GetBitContext last_gb;

  1653.     VLC *vlc;

  1654.     uint8_t *code_table;

  1655. 

  1656.     /* low frequencies (called big values) */

  1657.     s_index = 0;

  1658.     for(i=0;i<3;i++) {

  1659.         j = g->region_size[i];

  1660.         if (j == 0)

  1661.             continue;

  1662.         /* select vlc table */

  1663.         k = g->table_select[i];

  1664.         l = mpa_huff_data[k][0];

  1665.         linbits = mpa_huff_data[k][1];

  1666.         vlc = &huff_vlc[l];

  1667.         code_table = huff_code_table[l];

  1668. 

  1669.         /* read huffcode and compute each couple */

  1670.         for(;j>0;j--) {

  1671.             if (get_bits_count(&s->gb) >= end_pos)

  1672.                 break;

  1673.             if (code_table) {

  1674.                 code = get_vlc(&s->gb, vlc);

  1675.                 if (code < 0)

  1676.                     return -1;

  1677.                 y = code_table[code];

  1678.                 x = y >> 4;

  1679.                 y = y & 0x0f;

  1680.             } else {

  1681.                 x = 0;

  1682.                 y = 0;

  1683.             }

  1684.             dprintf("region=%d n=%d x=%d y=%d exp=%d\n", 

  1685.                     i, g->region_size[i] - j, x, y, exponents[s_index]);

  1686.             if (x) {

  1687.                 if (x == 15)

  1688.                     x += get_bitsz(&s->gb, linbits);

  1689.                 v = l3_unscale(x, exponents[s_index]);

  1690.                 if (get_bits1(&s->gb))

  1691.                     v = -v;

  1692.             } else {

  1693.                 v = 0;

  1694.             }

  1695.             g->sb_hybrid[s_index++] = v;

  1696.             if (y) {

  1697.                 if (y == 15)

  1698.                     y += get_bitsz(&s->gb, linbits);

  1699.                 v = l3_unscale(y, exponents[s_index]);

  1700.                 if (get_bits1(&s->gb))

  1701.                     v = -v;

  1702.             } else {

  1703.                 v = 0;

  1704.             }

  1705.             g->sb_hybrid[s_index++] = v;

  1706.         }

  1707.     }

  1708.             

  1709.     /* high frequencies */

  1710.     vlc = &huff_quad_vlc[g->count1table_select];

  1711.     last_gb.buffer = NULL;

  1712.     while (s_index <= 572) {

  1713.         pos = get_bits_count(&s->gb);

  1714.         if (pos >= end_pos) {

  1715.             if (pos > end_pos && last_gb.buffer != NULL) {

  1716.                 /* some encoders generate an incorrect size for this

  1717.                    part. We must go back into the data */

  1718.                 s_index -= 4;

  1719.                 s->gb = last_gb;

  1720.             }

  1721.             break;

  1722.         }

  1723.         last_gb= s->gb;

  1724. 

  1725.         code = get_vlc(&s->gb, vlc);

  1726.         dprintf("t=%d code=%d\n", g->count1table_select, code);

  1727.         if (code < 0)

  1728.             return -1;

  1729.         for(i=0;i<4;i++) {

  1730.             if (code & (8 >> i)) {

  1731.                 /* non zero value. Could use a hand coded function for

  1732.                    'one' value */

  1733.                 v = l3_unscale(1, exponents[s_index]);

  1734.                 if(get_bits1(&s->gb))

  1735.                     v = -v;

  1736.             } else {

  1737.                 v = 0;

  1738.             }

  1739.             g->sb_hybrid[s_index++] = v;

  1740.         }

  1741.     }

  1742.     while (s_index < 576)

  1743.         g->sb_hybrid[s_index++] = 0;

  1744.     return 0;

  1745. }

  1746. 

  1747. /* Reorder short blocks from bitstream order to interleaved order. It

  1748.    would be faster to do it in parsing, but the code would be far more

  1749.    complicated */

  1750. static void reorder_block(MPADecodeContext *s, GranuleDef *g)

  1751. {

  1752.     int i, j, k, len;

  1753.     int32_t *ptr, *dst, *ptr1;

  1754.     int32_t tmp[576];

  1755. 

  1756.     if (g->block_type != 2)

  1757.         return;

  1758. 

  1759.     if (g->switch_point) {

  1760.         if (s->sample_rate_index != 8) {

  1761.             ptr = g->sb_hybrid + 36;

  1762.         } else {

  1763.             ptr = g->sb_hybrid + 48;

  1764.         }

  1765.     } else {

  1766.         ptr = g->sb_hybrid;

  1767.     }

  1768.     

  1769.     for(i=g->short_start;i<13;i++) {

  1770.         len = band_size_short[s->sample_rate_index][i];

  1771.         ptr1 = ptr;

  1772.         for(k=0;k<3;k++) {

  1773.             dst = tmp + k;

  1774.             for(j=len;j>0;j--) {

  1775.                 *dst = *ptr++;

  1776.                 dst += 3;

  1777.             }

  1778.         }

  1779.         memcpy(ptr1, tmp, len * 3 * sizeof(int32_t));

  1780.     }

  1781. }

  1782. 

  1783. #define ISQRT2 FIXR(0.70710678118654752440)

  1784. 

  1785. static void compute_stereo(MPADecodeContext *s,

  1786.                            GranuleDef *g0, GranuleDef *g1)

  1787. {

  1788.     int i, j, k, l;

  1789.     int32_t v1, v2;

  1790.     int sf_max, tmp0, tmp1, sf, len, non_zero_found;

  1791.     int32_t (*is_tab)[16];

  1792.     int32_t *tab0, *tab1;

  1793.     int non_zero_found_short[3];

  1794. 

  1795.     /* intensity stereo */

  1796.     if (s->mode_ext & MODE_EXT_I_STEREO) {

  1797.         if (!s->lsf) {

  1798.             is_tab = is_table;

  1799.             sf_max = 7;

  1800.         } else {

  1801.             is_tab = is_table_lsf[g1->scalefac_compress & 1];

  1802.             sf_max = 16;

  1803.         }

  1804.             

  1805.         tab0 = g0->sb_hybrid + 576;

  1806.         tab1 = g1->sb_hybrid + 576;

  1807. 

  1808.         non_zero_found_short[0] = 0;

  1809.         non_zero_found_short[1] = 0;

  1810.         non_zero_found_short[2] = 0;

  1811.         k = (13 - g1->short_start) * 3 + g1->long_end - 3;

  1812.         for(i = 12;i >= g1->short_start;i--) {

  1813.             /* for last band, use previous scale factor */

  1814.             if (i != 11)

  1815.                 k -= 3;

  1816.             len = band_size_short[s->sample_rate_index][i];

  1817.             for(l=2;l>=0;l--) {

  1818.                 tab0 -= len;

  1819.                 tab1 -= len;

  1820.                 if (!non_zero_found_short[l]) {

  1821.                     /* test if non zero band. if so, stop doing i-stereo */

  1822.                     for(j=0;j<len;j++) {

  1823.                         if (tab1[j] != 0) {

  1824.                             non_zero_found_short[l] = 1;

  1825.                             goto found1;

  1826.                         }

  1827.                     }

  1828.                     sf = g1->scale_factors[k + l];

  1829.                     if (sf >= sf_max)

  1830.                         goto found1;

  1831. 

  1832.                     v1 = is_tab[0][sf];

  1833.                     v2 = is_tab[1][sf];

  1834.                     for(j=0;j<len;j++) {

  1835.                         tmp0 = tab0[j];

  1836.                         tab0[j] = MULL(tmp0, v1);

  1837.                         tab1[j] = MULL(tmp0, v2);

  1838.                     }

  1839.                 } else {

  1840.                 found1:

  1841.                     if (s->mode_ext & MODE_EXT_MS_STEREO) {

  1842.                         /* lower part of the spectrum : do ms stereo

  1843.                            if enabled */

  1844.                         for(j=0;j<len;j++) {

  1845.                             tmp0 = tab0[j];

  1846.                             tmp1 = tab1[j];

  1847.                             tab0[j] = MULL(tmp0 + tmp1, ISQRT2);

  1848.                             tab1[j] = MULL(tmp0 - tmp1, ISQRT2);

  1849.                         }

  1850.                     }

  1851.                 }

  1852.             }

  1853.         }

  1854. 

  1855.         non_zero_found = non_zero_found_short[0] | 

  1856.             non_zero_found_short[1] | 

  1857.             non_zero_found_short[2];

  1858. 

  1859.         for(i = g1->long_end - 1;i >= 0;i--) {

  1860.             len = band_size_long[s->sample_rate_index][i];

  1861.             tab0 -= len;

  1862.             tab1 -= len;

  1863.             /* test if non zero band. if so, stop doing i-stereo */

  1864.             if (!non_zero_found) {

  1865.                 for(j=0;j<len;j++) {

  1866.                     if (tab1[j] != 0) {

  1867.                         non_zero_found = 1;

  1868.                         goto found2;

  1869.                     }

  1870.                 }

  1871.                 /* for last band, use previous scale factor */

  1872.                 k = (i == 21) ? 20 : i;

  1873.                 sf = g1->scale_factors[k];

  1874.                 if (sf >= sf_max)

  1875.                     goto found2;

  1876.                 v1 = is_tab[0][sf];

  1877.                 v2 = is_tab[1][sf];

  1878.                 for(j=0;j<len;j++) {

  1879.                     tmp0 = tab0[j];

  1880.                     tab0[j] = MULL(tmp0, v1);

  1881.                     tab1[j] = MULL(tmp0, v2);

  1882.                 }

  1883.             } else {

  1884.             found2:

  1885.                 if (s->mode_ext & MODE_EXT_MS_STEREO) {

  1886.                     /* lower part of the spectrum : do ms stereo

  1887.                        if enabled */

  1888.                     for(j=0;j<len;j++) {

  1889.                         tmp0 = tab0[j];

  1890.                         tmp1 = tab1[j];

  1891.                         tab0[j] = MULL(tmp0 + tmp1, ISQRT2);

  1892.                         tab1[j] = MULL(tmp0 - tmp1, ISQRT2);

  1893.                     }

  1894.                 }

  1895.             }

  1896.         }

  1897.     } else if (s->mode_ext & MODE_EXT_MS_STEREO) {

  1898.         /* ms stereo ONLY */

  1899.         /* NOTE: the 1/sqrt(2) normalization factor is included in the

  1900.            global gain */

  1901.         tab0 = g0->sb_hybrid;

  1902.         tab1 = g1->sb_hybrid;

  1903.         for(i=0;i<576;i++) {

  1904.             tmp0 = tab0[i];

  1905.             tmp1 = tab1[i];

  1906.             tab0[i] = tmp0 + tmp1;

  1907.             tab1[i] = tmp0 - tmp1;

  1908.         }

  1909.     }

  1910. }

  1911. 

  1912. static void compute_antialias_integer(MPADecodeContext *s,

  1913.                               GranuleDef *g)

  1914. {

  1915.     int32_t *ptr, *csa;

  1916.     int n, i;

  1917. 

  1918.     /* we antialias only "long" bands */

  1919.     if (g->block_type == 2) {

  1920.         if (!g->switch_point)

  1921.             return;

  1922.         /* XXX: check this for 8000Hz case */

  1923.         n = 1;

  1924.     } else {

  1925.         n = SBLIMIT - 1;

  1926.     }

  1927.     

  1928.     ptr = g->sb_hybrid + 18;

  1929.     for(i = n;i > 0;i--) {

  1930.         int tmp0, tmp1, tmp2;

  1931.         csa = &csa_table[0][0];

  1932. #define INT_AA(j) \

  1933.             tmp0 = ptr[-1-j];\

  1934.             tmp1 = ptr[   j];\

  1935.             tmp2= MULH(tmp0 + tmp1, csa[0+4*j]);\

  1936.             ptr[-1-j] = 4*(tmp2 - MULH(tmp1, csa[2+4*j]));\

  1937.             ptr[   j] = 4*(tmp2 + MULH(tmp0, csa[3+4*j]));

  1938. 

  1939.         INT_AA(0)

  1940.         INT_AA(1)

  1941.         INT_AA(2)

  1942.         INT_AA(3)

  1943.         INT_AA(4)

  1944.         INT_AA(5)

  1945.         INT_AA(6)

  1946.         INT_AA(7)

  1947.             

  1948.         ptr += 18;       

  1949.     }

  1950. }

  1951. 

  1952. static void compute_antialias_float(MPADecodeContext *s,

  1953.                               GranuleDef *g)

  1954. {

  1955.     int32_t *ptr;

  1956.     int n, i;

  1957. 

  1958.     /* we antialias only "long" bands */

  1959.     if (g->block_type == 2) {

  1960.         if (!g->switch_point)

  1961.             return;

  1962.         /* XXX: check this for 8000Hz case */

  1963.         n = 1;

  1964.     } else {

  1965.         n = SBLIMIT - 1;

  1966.     }

  1967.     

  1968.     ptr = g->sb_hybrid + 18;

  1969.     for(i = n;i > 0;i--) {

  1970.         float tmp0, tmp1;

  1971.         float *csa = &csa_table_float[0][0];       

  1972. #define FLOAT_AA(j)\

  1973.         tmp0= ptr[-1-j];\

  1974.         tmp1= ptr[   j];\

  1975.         ptr[-1-j] = lrintf(tmp0 * csa[0+4*j] - tmp1 * csa[1+4*j]);\

  1976.         ptr[   j] = lrintf(tmp0 * csa[1+4*j] + tmp1 * csa[0+4*j]);

  1977.         

  1978.         FLOAT_AA(0)

  1979.         FLOAT_AA(1)

  1980.         FLOAT_AA(2)

  1981.         FLOAT_AA(3)

  1982.         FLOAT_AA(4)

  1983.         FLOAT_AA(5)

  1984.         FLOAT_AA(6)

  1985.         FLOAT_AA(7)

  1986. 

  1987.         ptr += 18;       

  1988.     }

  1989. }

  1990. 

  1991. static void compute_imdct(MPADecodeContext *s,

  1992.                           GranuleDef *g, 

  1993.                           int32_t *sb_samples,

  1994.                           int32_t *mdct_buf)

  1995. {

  1996.     int32_t *ptr, *win, *win1, *buf, *out_ptr, *ptr1;

  1997.     int32_t out2[12];

  1998.     int i, j, mdct_long_end, v, sblimit;

  1999. 

  2000.     /* find last non zero block */

  2001.     ptr = g->sb_hybrid + 576;

  2002.     ptr1 = g->sb_hybrid + 2 * 18;

  2003.     while (ptr >= ptr1) {

  2004.         ptr -= 6;

  2005.         v = ptr[0] | ptr[1] | ptr[2] | ptr[3] | ptr[4] | ptr[5];

  2006.         if (v != 0)

  2007.             break;

  2008.     }

  2009.     sblimit = ((ptr - g->sb_hybrid) / 18) + 1;

  2010. 

  2011.     if (g->block_type == 2) {

  2012.         /* XXX: check for 8000 Hz */

  2013.         if (g->switch_point)

  2014.             mdct_long_end = 2;

  2015.         else

  2016.             mdct_long_end = 0;

  2017.     } else {

  2018.         mdct_long_end = sblimit;

  2019.     }

  2020. 

  2021.     buf = mdct_buf;

  2022.     ptr = g->sb_hybrid;

  2023.     for(j=0;j<mdct_long_end;j++) {

  2024.         /* apply window & overlap with previous buffer */

  2025.         out_ptr = sb_samples + j;

  2026.         /* select window */

  2027.         if (g->switch_point && j < 2)

  2028.             win1 = mdct_win[0];

  2029.         else

  2030.             win1 = mdct_win[g->block_type];

  2031.         /* select frequency inversion */

  2032.         win = win1 + ((4 * 36) & -(j & 1));

  2033.         imdct36(out_ptr, buf, ptr, win);

  2034.         out_ptr += 18*SBLIMIT;

  2035.         ptr += 18;

  2036.         buf += 18;

  2037.     }

  2038.     for(j=mdct_long_end;j<sblimit;j++) {

  2039.         /* select frequency inversion */

  2040.         win = mdct_win[2] + ((4 * 36) & -(j & 1));

  2041.         out_ptr = sb_samples + j;

  2042.         

  2043.         for(i=0; i<6; i++){

  2044.             *out_ptr = buf[i];

  2045.             out_ptr += SBLIMIT;

  2046.         }

  2047.         imdct12(out2, ptr + 0);

  2048.         for(i=0;i<6;i++) {

  2049.             *out_ptr = MULH(out2[i], win[i]) + buf[i + 6*1];

  2050.             buf[i + 6*2] = MULH(out2[i + 6], win[i + 6]);

  2051.             out_ptr += SBLIMIT;

  2052.         }

  2053.         imdct12(out2, ptr + 1);

  2054.         for(i=0;i<6;i++) {

  2055.             *out_ptr = MULH(out2[i], win[i]) + buf[i + 6*2];

  2056.             buf[i + 6*0] = MULH(out2[i + 6], win[i + 6]);

  2057.             out_ptr += SBLIMIT;

  2058.         }

  2059.         imdct12(out2, ptr + 2);

  2060.         for(i=0;i<6;i++) {

  2061.             buf[i + 6*0] = MULH(out2[i], win[i]) + buf[i + 6*0];

  2062.             buf[i + 6*1] = MULH(out2[i + 6], win[i + 6]);

  2063.             buf[i + 6*2] = 0;

  2064.         }

  2065.         ptr += 18;

  2066.         buf += 18;

  2067.     }

  2068.     /* zero bands */

  2069.     for(j=sblimit;j<SBLIMIT;j++) {

  2070.         /* overlap */

  2071.         out_ptr = sb_samples + j;

  2072.         for(i=0;i<18;i++) {

  2073.             *out_ptr = buf[i];

  2074.             buf[i] = 0;

  2075.             out_ptr += SBLIMIT;

  2076.         }

  2077.         buf += 18;

  2078.     }

  2079. }

  2080. 

  2081. #if defined(DEBUG)

  2082. void sample_dump(int fnum, int32_t *tab, int n)

  2083. {

  2084.     static FILE *files[16], *f;

  2085.     char buf[512];

  2086.     int i;

  2087.     int32_t v;

  2088.     

  2089.     f = files[fnum];

  2090.     if (!f) {

  2091.         snprintf(buf, sizeof(buf), "/tmp/out%d.%s.pcm", 

  2092.                 fnum, 

  2093. #ifdef USE_HIGHPRECISION

  2094.                 "hp"

  2095. #else

  2096.                 "lp"

  2097. #endif

  2098.                 );

  2099.         f = fopen(buf, "w");

  2100.         if (!f)

  2101.             return;

  2102.         files[fnum] = f;

  2103.     }

  2104.     

  2105.     if (fnum == 0) {

  2106.         static int pos = 0;

  2107.         av_log(NULL, AV_LOG_DEBUG, "pos=%d\n", pos);

  2108.         for(i=0;i<n;i++) {

  2109.             av_log(NULL, AV_LOG_DEBUG, " %0.4f", (double)tab[i] / FRAC_ONE);

  2110.             if ((i % 18) == 17)

  2111.                 av_log(NULL, AV_LOG_DEBUG, "\n");

  2112.         }

  2113.         pos += n;

  2114.     }

  2115.     for(i=0;i<n;i++) {

  2116.         /* normalize to 23 frac bits */

  2117.         v = tab[i] << (23 - FRAC_BITS);

  2118.         fwrite(&v, 1, sizeof(int32_t), f);

  2119.     }

  2120. }

  2121. #endif

  2122. 

  2123. 

  2124. /* main layer3 decoding function */

  2125. static int mp_decode_layer3(MPADecodeContext *s)

  2126. {

  2127.     int nb_granules, main_data_begin, private_bits;

  2128.     int gr, ch, blocksplit_flag, i, j, k, n, bits_pos, bits_left;

  2129.     GranuleDef granules[2][2], *g;

  2130.     int16_t exponents[576];

  2131. 

  2132.     /* read side info */

  2133.     if (s->lsf) {

  2134.         main_data_begin = get_bits(&s->gb, 8);

  2135.         if (s->nb_channels == 2)

  2136.             private_bits = get_bits(&s->gb, 2);

  2137.         else

  2138.             private_bits = get_bits(&s->gb, 1);

  2139.         nb_granules = 1;

  2140.     } else {

  2141.         main_data_begin = get_bits(&s->gb, 9);

  2142.         if (s->nb_channels == 2)

  2143.             private_bits = get_bits(&s->gb, 3);

  2144.         else

  2145.             private_bits = get_bits(&s->gb, 5);

  2146.         nb_granules = 2;

  2147.         for(ch=0;ch<s->nb_channels;ch++) {

  2148.             granules[ch][0].scfsi = 0; /* all scale factors are transmitted */

  2149.             granules[ch][1].scfsi = get_bits(&s->gb, 4);

  2150.         }

  2151.     }

  2152.     

  2153.     for(gr=0;gr<nb_granules;gr++) {

  2154.         for(ch=0;ch<s->nb_channels;ch++) {

  2155.             dprintf("gr=%d ch=%d: side_info\n", gr, ch);

  2156.             g = &granules[ch][gr];

  2157.             g->part2_3_length = get_bits(&s->gb, 12);

  2158.             g->big_values = get_bits(&s->gb, 9);

  2159.             g->global_gain = get_bits(&s->gb, 8);

  2160.             /* if MS stereo only is selected, we precompute the

  2161.                1/sqrt(2) renormalization factor */

  2162.             if ((s->mode_ext & (MODE_EXT_MS_STEREO | MODE_EXT_I_STEREO)) == 

  2163.                 MODE_EXT_MS_STEREO)

  2164.                 g->global_gain -= 2;

  2165.             if (s->lsf)

  2166.                 g->scalefac_compress = get_bits(&s->gb, 9);

  2167.             else

  2168.                 g->scalefac_compress = get_bits(&s->gb, 4);

  2169.             blocksplit_flag = get_bits(&s->gb, 1);

  2170.             if (blocksplit_flag) {

  2171.                 g->block_type = get_bits(&s->gb, 2);

  2172.                 if (g->block_type == 0)

  2173.                     return -1;

  2174.                 g->switch_point = get_bits(&s->gb, 1);

  2175.                 for(i=0;i<2;i++)

  2176.                     g->table_select[i] = get_bits(&s->gb, 5);

  2177.                 for(i=0;i<3;i++) 

  2178.                     g->subblock_gain[i] = get_bits(&s->gb, 3);

  2179.                 /* compute huffman coded region sizes */

  2180.                 if (g->block_type == 2)

  2181.                     g->region_size[0] = (36 / 2);

  2182.                 else {

  2183.                     if (s->sample_rate_index <= 2) 

  2184.                         g->region_size[0] = (36 / 2);

  2185.                     else if (s->sample_rate_index != 8) 

  2186.                         g->region_size[0] = (54 / 2);

  2187.                     else

  2188.                         g->region_size[0] = (108 / 2);

  2189.                 }

  2190.                 g->region_size[1] = (576 / 2);

  2191.             } else {

  2192.                 int region_address1, region_address2, l;

  2193.                 g->block_type = 0;

  2194.                 g->switch_point = 0;

  2195.                 for(i=0;i<3;i++)

  2196.                     g->table_select[i] = get_bits(&s->gb, 5);

  2197.                 /* compute huffman coded region sizes */

  2198.                 region_address1 = get_bits(&s->gb, 4);

  2199.                 region_address2 = get_bits(&s->gb, 3);

  2200.                 dprintf("region1=%d region2=%d\n", 

  2201.                         region_address1, region_address2);

  2202.                 g->region_size[0] = 

  2203.                     band_index_long[s->sample_rate_index][region_address1 + 1] >> 1;

  2204.                 l = region_address1 + region_address2 + 2;

  2205.                 /* should not overflow */

  2206.                 if (l > 22)

  2207.                     l = 22;

  2208.                 g->region_size[1] = 

  2209.                     band_index_long[s->sample_rate_index][l] >> 1;

  2210.             }

  2211.             /* convert region offsets to region sizes and truncate

  2212.                size to big_values */

  2213.             g->region_size[2] = (576 / 2);

  2214.             j = 0;

  2215.             for(i=0;i<3;i++) {

  2216.                 k = g->region_size[i];

  2217.                 if (k > g->big_values)

  2218.                     k = g->big_values;

  2219.                 g->region_size[i] = k - j;

  2220.                 j = k;

  2221.             }

  2222. 

  2223.             /* compute band indexes */

  2224.             if (g->block_type == 2) {

  2225.                 if (g->switch_point) {

  2226.                     /* if switched mode, we handle the 36 first samples as

  2227.                        long blocks.  For 8000Hz, we handle the 48 first

  2228.                        exponents as long blocks (XXX: check this!) */

  2229.                     if (s->sample_rate_index <= 2)

  2230.                         g->long_end = 8;

  2231.                     else if (s->sample_rate_index != 8)

  2232.                         g->long_end = 6;

  2233.                     else

  2234.                         g->long_end = 4; /* 8000 Hz */

  2235.                     

  2236.                     if (s->sample_rate_index != 8)

  2237.                         g->short_start = 3;

  2238.                     else

  2239.                         g->short_start = 2; 

  2240.                 } else {

  2241.                     g->long_end = 0;

  2242.                     g->short_start = 0;

  2243.                 }

  2244.             } else {

  2245.                 g->short_start = 13;

  2246.                 g->long_end = 22;

  2247.             }

  2248.             

  2249.             g->preflag = 0;

  2250.             if (!s->lsf)

  2251.                 g->preflag = get_bits(&s->gb, 1);

  2252.             g->scalefac_scale = get_bits(&s->gb, 1);

  2253.             g->count1table_select = get_bits(&s->gb, 1);

  2254.             dprintf("block_type=%d switch_point=%d\n",

  2255.                     g->block_type, g->switch_point);

  2256.         }

  2257.     }

  2258. 

  2259.   if (!s->adu_mode) {

  2260.     /* now we get bits from the main_data_begin offset */

  2261.     dprintf("seekback: %d\n", main_data_begin);

  2262.     seek_to_maindata(s, main_data_begin);

  2263.   }

  2264. 

  2265.     for(gr=0;gr<nb_granules;gr++) {

  2266.         for(ch=0;ch<s->nb_channels;ch++) {

  2267.             g = &granules[ch][gr];

  2268.             

  2269.             bits_pos = get_bits_count(&s->gb);

  2270.             

  2271.             if (!s->lsf) {

  2272.                 uint8_t *sc;

  2273.                 int slen, slen1, slen2;

  2274. 

  2275.                 /* MPEG1 scale factors */

  2276.                 slen1 = slen_table[0][g->scalefac_compress];

  2277.                 slen2 = slen_table[1][g->scalefac_compress];

  2278.                 dprintf("slen1=%d slen2=%d\n", slen1, slen2);

  2279.                 if (g->block_type == 2) {

  2280.                     n = g->switch_point ? 17 : 18;

  2281.                     j = 0;

  2282.                     for(i=0;i<n;i++)

  2283.                         g->scale_factors[j++] = get_bitsz(&s->gb, slen1);

  2284.                     for(i=0;i<18;i++)

  2285.                         g->scale_factors[j++] = get_bitsz(&s->gb, slen2);

  2286.                     for(i=0;i<3;i++)

  2287.                         g->scale_factors[j++] = 0;

  2288.                 } else {

  2289.                     sc = granules[ch][0].scale_factors;

  2290.                     j = 0;

  2291.                     for(k=0;k<4;k++) {

  2292.                         n = (k == 0 ? 6 : 5);

  2293.                         if ((g->scfsi & (0x8 >> k)) == 0) {

  2294.                             slen = (k < 2) ? slen1 : slen2;

  2295.                             for(i=0;i<n;i++)

  2296.                                 g->scale_factors[j++] = get_bitsz(&s->gb, slen);

  2297.                         } else {

  2298.                             /* simply copy from last granule */

  2299.                             for(i=0;i<n;i++) {

  2300.                                 g->scale_factors[j] = sc[j];

  2301.                                 j++;

  2302.                             }

  2303.                         }

  2304.                     }

  2305.                     g->scale_factors[j++] = 0;

  2306.                 }

  2307. #if defined(DEBUG)

  2308.                 {

  2309.                     printf("scfsi=%x gr=%d ch=%d scale_factors:\n", 

  2310.                            g->scfsi, gr, ch);

  2311.                     for(i=0;i<j;i++)

  2312.                         printf(" %d", g->scale_factors[i]);

  2313.                     printf("\n");

  2314.                 }

  2315. #endif

  2316.             } else {

  2317.                 int tindex, tindex2, slen[4], sl, sf;

  2318. 

  2319.                 /* LSF scale factors */

  2320.                 if (g->block_type == 2) {

  2321.                     tindex = g->switch_point ? 2 : 1;

  2322.                 } else {

  2323.                     tindex = 0;

  2324.                 }

  2325.                 sf = g->scalefac_compress;

  2326.                 if ((s->mode_ext & MODE_EXT_I_STEREO) && ch == 1) {

  2327.                     /* intensity stereo case */

  2328.                     sf >>= 1;

  2329.                     if (sf < 180) {

  2330.                         lsf_sf_expand(slen, sf, 6, 6, 0);

  2331.                         tindex2 = 3;

  2332.                     } else if (sf < 244) {

  2333.                         lsf_sf_expand(slen, sf - 180, 4, 4, 0);

  2334.                         tindex2 = 4;

  2335.                     } else {

  2336.                         lsf_sf_expand(slen, sf - 244, 3, 0, 0);

  2337.                         tindex2 = 5;

  2338.                     }

  2339.                 } else {

  2340.                     /* normal case */

  2341.                     if (sf < 400) {

  2342.                         lsf_sf_expand(slen, sf, 5, 4, 4);

  2343.                         tindex2 = 0;

  2344.                     } else if (sf < 500) {

  2345.                         lsf_sf_expand(slen, sf - 400, 5, 4, 0);

  2346.                         tindex2 = 1;

  2347.                     } else {

  2348.                         lsf_sf_expand(slen, sf - 500, 3, 0, 0);

  2349.                         tindex2 = 2;

  2350.                         g->preflag = 1;

  2351.                     }

  2352.                 }

  2353. 

  2354.                 j = 0;

  2355.                 for(k=0;k<4;k++) {

  2356.                     n = lsf_nsf_table[tindex2][tindex][k];

  2357.                     sl = slen[k];

  2358.                     for(i=0;i<n;i++)

  2359.                         g->scale_factors[j++] = get_bitsz(&s->gb, sl);

  2360.                 }

  2361.                 /* XXX: should compute exact size */

  2362.                 for(;j<40;j++)

  2363.                     g->scale_factors[j] = 0;

  2364. #if defined(DEBUG)

  2365.                 {

  2366.                     printf("gr=%d ch=%d scale_factors:\n", 

  2367.                            gr, ch);

  2368.                     for(i=0;i<40;i++)

  2369.                         printf(" %d", g->scale_factors[i]);

  2370.                     printf("\n");

  2371.                 }

  2372. #endif

  2373.             }

  2374. 

  2375.             exponents_from_scale_factors(s, g, exponents);

  2376. 

  2377.             /* read Huffman coded residue */

  2378.             if (huffman_decode(s, g, exponents,

  2379.                                bits_pos + g->part2_3_length) < 0)

  2380.                 return -1;

  2381. #if defined(DEBUG)

  2382.             sample_dump(0, g->sb_hybrid, 576);

  2383. #endif

  2384. 

  2385.             /* skip extension bits */

  2386.             bits_left = g->part2_3_length - (get_bits_count(&s->gb) - bits_pos);

  2387.             if (bits_left < 0) {

  2388.                 dprintf("bits_left=%d\n", bits_left);

  2389.                 return -1;

  2390.             }

  2391.             while (bits_left >= 16) {

  2392.                 skip_bits(&s->gb, 16);

  2393.                 bits_left -= 16;

  2394.             }

  2395.             if (bits_left > 0)

  2396.                 skip_bits(&s->gb, bits_left);

  2397.         } /* ch */

  2398. 

  2399.         if (s->nb_channels == 2)

  2400.             compute_stereo(s, &granules[0][gr], &granules[1][gr]);

  2401. 

  2402.         for(ch=0;ch<s->nb_channels;ch++) {

  2403.             g = &granules[ch][gr];

  2404. 

  2405.             reorder_block(s, g);

  2406. #if defined(DEBUG)

  2407.             sample_dump(0, g->sb_hybrid, 576);

  2408. #endif

  2409.             s->compute_antialias(s, g);

  2410. #if defined(DEBUG)

  2411.             sample_dump(1, g->sb_hybrid, 576);

  2412. #endif

  2413.             compute_imdct(s, g, &s->sb_samples[ch][18 * gr][0], s->mdct_buf[ch]); 

  2414. #if defined(DEBUG)

  2415.             sample_dump(2, &s->sb_samples[ch][18 * gr][0], 576);

  2416. #endif

  2417.         }

  2418.     } /* gr */

  2419.     return nb_granules * 18;

  2420. }

  2421. 

  2422. static int mp_decode_frame(MPADecodeContext *s, 

  2423.                            OUT_INT *samples)

  2424. {

  2425.     int i, nb_frames, ch;

  2426.     OUT_INT *samples_ptr;

  2427. 

  2428.     init_get_bits(&s->gb, s->inbuf + HEADER_SIZE, 

  2429.                   (s->inbuf_ptr - s->inbuf - HEADER_SIZE)*8);

  2430.     

  2431.     /* skip error protection field */

  2432.     if (s->error_protection)

  2433.         get_bits(&s->gb, 16);

  2434. 

  2435.     dprintf("frame %d:\n", s->frame_count);

  2436.     switch(s->layer) {

  2437.     case 1:

  2438.         nb_frames = mp_decode_layer1(s);

  2439.         break;

  2440.     case 2:

  2441.         nb_frames = mp_decode_layer2(s);

  2442.         break;

  2443.     case 3:

  2444.     default:

  2445.         nb_frames = mp_decode_layer3(s);

  2446.         break;

  2447.     }

  2448. #if defined(DEBUG)

  2449.     for(i=0;i<nb_frames;i++) {

  2450.         for(ch=0;ch<s->nb_channels;ch++) {

  2451.             int j;

  2452.             printf("%d-%d:", i, ch);

  2453.             for(j=0;j<SBLIMIT;j++)

  2454.                 printf(" %0.6f", (double)s->sb_samples[ch][i][j] / FRAC_ONE);

  2455.             printf("\n");

  2456.         }

  2457.     }

  2458. #endif

  2459.     /* apply the synthesis filter */

  2460.     for(ch=0;ch<s->nb_channels;ch++) {

  2461.         samples_ptr = samples + ch;

  2462.         for(i=0;i<nb_frames;i++) {

  2463.             ff_mpa_synth_filter(s->synth_buf[ch], &(s->synth_buf_offset[ch]),

  2464. 			 window, &s->dither_state,

  2465. 			 samples_ptr, s->nb_channels,

  2466.                          s->sb_samples[ch][i]);

  2467.             samples_ptr += 32 * s->nb_channels;

  2468.         }

  2469.     }

  2470. #ifdef DEBUG

  2471.     s->frame_count++;        

  2472. #endif

  2473.     return nb_frames * 32 * sizeof(OUT_INT) * s->nb_channels;

  2474. }

  2475. 

  2476. static int decode_frame(AVCodecContext * avctx,

  2477. 			void *data, int *data_size,

  2478. 			uint8_t * buf, int buf_size)

  2479. {

  2480.     MPADecodeContext *s = avctx->priv_data;

  2481.     uint32_t header;

  2482.     uint8_t *buf_ptr;

  2483.     int len, out_size;

  2484.     OUT_INT *out_samples = data;

  2485. 

  2486.     buf_ptr = buf;

  2487.     while (buf_size > 0) {

  2488. 	len = s->inbuf_ptr - s->inbuf;

  2489. 	if (s->frame_size == 0) {

  2490.             /* special case for next header for first frame in free

  2491.                format case (XXX: find a simpler method) */

  2492.             if (s->free_format_next_header != 0) {

  2493.                 s->inbuf[0] = s->free_format_next_header >> 24;

  2494.                 s->inbuf[1] = s->free_format_next_header >> 16;

  2495.                 s->inbuf[2] = s->free_format_next_header >> 8;

  2496.                 s->inbuf[3] = s->free_format_next_header;

  2497.                 s->inbuf_ptr = s->inbuf + 4;

  2498.                 s->free_format_next_header = 0;

  2499.                 goto got_header;

  2500.             }

  2501. 	    /* no header seen : find one. We need at least HEADER_SIZE

  2502.                bytes to parse it */

  2503. 	    len = HEADER_SIZE - len;

  2504. 	    if (len > buf_size)

  2505. 		len = buf_size;

  2506. 	    if (len > 0) {

  2507. 		memcpy(s->inbuf_ptr, buf_ptr, len);

  2508. 		buf_ptr += len;

  2509. 		buf_size -= len;

  2510. 		s->inbuf_ptr += len;

  2511. 	    }

  2512. 	    if ((s->inbuf_ptr - s->inbuf) >= HEADER_SIZE) {

  2513.             got_header:

  2514. 		header = (s->inbuf[0] << 24) | (s->inbuf[1] << 16) |

  2515. 		    (s->inbuf[2] << 8) | s->inbuf[3];

  2516. 

  2517. 		if (ff_mpa_check_header(header) < 0) {

  2518. 		    /* no sync found : move by one byte (inefficient, but simple!) */

  2519. 		    memmove(s->inbuf, s->inbuf + 1, s->inbuf_ptr - s->inbuf - 1);

  2520. 		    s->inbuf_ptr--;

  2521.                     dprintf("skip %x\n", header);

  2522.                     /* reset free format frame size to give a chance

  2523.                        to get a new bitrate */

  2524.                     s->free_format_frame_size = 0;

  2525. 		} else {

  2526. 		    if (decode_header(s, header) == 1) {

  2527.                         /* free format: prepare to compute frame size */

  2528. 			s->frame_size = -1;

  2529.                     }

  2530.                     /* update codec info */

  2531.                     avctx->sample_rate = s->sample_rate;

  2532.                     avctx->channels = s->nb_channels;

  2533.                     avctx->bit_rate = s->bit_rate;

  2534.                     avctx->sub_id = s->layer;

  2535.                     switch(s->layer) {

  2536.                     case 1:

  2537.                         avctx->frame_size = 384;

  2538.                         break;

  2539.                     case 2:

  2540.                         avctx->frame_size = 1152;

  2541.                         break;

  2542.                     case 3:

  2543.                         if (s->lsf)

  2544.                             avctx->frame_size = 576;

  2545.                         else

  2546.                             avctx->frame_size = 1152;

  2547.                         break;

  2548.                     }

  2549. 		}

  2550. 	    }

  2551.         } else if (s->frame_size == -1) {

  2552.             /* free format : find next sync to compute frame size */

  2553. 	    len = MPA_MAX_CODED_FRAME_SIZE - len;

  2554. 	    if (len > buf_size)

  2555. 		len = buf_size;

  2556.             if (len == 0) {

  2557. 		/* frame too long: resync */

  2558.                 s->frame_size = 0;

  2559. 		memmove(s->inbuf, s->inbuf + 1, s->inbuf_ptr - s->inbuf - 1);

  2560. 		s->inbuf_ptr--;

  2561.             } else {

  2562.                 uint8_t *p, *pend;

  2563.                 uint32_t header1;

  2564.                 int padding;

  2565. 

  2566.                 memcpy(s->inbuf_ptr, buf_ptr, len);

  2567.                 /* check for header */

  2568.                 p = s->inbuf_ptr - 3;

  2569.                 pend = s->inbuf_ptr + len - 4;

  2570.                 while (p <= pend) {

  2571.                     header = (p[0] << 24) | (p[1] << 16) |

  2572.                         (p[2] << 8) | p[3];

  2573.                     header1 = (s->inbuf[0] << 24) | (s->inbuf[1] << 16) |

  2574.                         (s->inbuf[2] << 8) | s->inbuf[3];

  2575.                     /* check with high probability that we have a

  2576.                        valid header */

  2577.                     if ((header & SAME_HEADER_MASK) ==

  2578.                         (header1 & SAME_HEADER_MASK)) {

  2579.                         /* header found: update pointers */

  2580.                         len = (p + 4) - s->inbuf_ptr;

  2581.                         buf_ptr += len;

  2582.                         buf_size -= len;

  2583.                         s->inbuf_ptr = p;

  2584.                         /* compute frame size */

  2585.                         s->free_format_next_header = header;

  2586.                         s->free_format_frame_size = s->inbuf_ptr - s->inbuf;

  2587.                         padding = (header1 >> 9) & 1;

  2588.                         if (s->layer == 1)

  2589.                             s->free_format_frame_size -= padding * 4;

  2590.                         else

  2591.                             s->free_format_frame_size -= padding;

  2592.                         dprintf("free frame size=%d padding=%d\n", 

  2593.                                 s->free_format_frame_size, padding);

  2594.                         decode_header(s, header1);

  2595.                         goto next_data;

  2596.                     }

  2597.                     p++;

  2598.                 }

  2599.                 /* not found: simply increase pointers */

  2600.                 buf_ptr += len;

  2601.                 s->inbuf_ptr += len;

  2602.                 buf_size -= len;

  2603.             }

  2604. 	} else if (len < s->frame_size) {

  2605.             if (s->frame_size > MPA_MAX_CODED_FRAME_SIZE)

  2606.                 s->frame_size = MPA_MAX_CODED_FRAME_SIZE;

  2607. 	    len = s->frame_size - len;

  2608. 	    if (len > buf_size)

  2609. 		len = buf_size;

  2610. 	    memcpy(s->inbuf_ptr, buf_ptr, len);

  2611. 	    buf_ptr += len;

  2612. 	    s->inbuf_ptr += len;

  2613. 	    buf_size -= len;

  2614. 	}

  2615.     next_data:

  2616.         if (s->frame_size > 0 && 

  2617.             (s->inbuf_ptr - s->inbuf) >= s->frame_size) {

  2618.             if (avctx->parse_only) {

  2619.                 /* simply return the frame data */

  2620.                 *(uint8_t **)data = s->inbuf;

  2621.                 out_size = s->inbuf_ptr - s->inbuf;

  2622.             } else {

  2623.                 out_size = mp_decode_frame(s, out_samples);

  2624.             }

  2625. 	    s->inbuf_ptr = s->inbuf;

  2626. 	    s->frame_size = 0;

  2627. 	    *data_size = out_size;

  2628. 	    break;

  2629. 	}

  2630.     }

  2631.     return buf_ptr - buf;

  2632. }

  2633. 

  2634. 

  2635. static int decode_frame_adu(AVCodecContext * avctx,

  2636. 			void *data, int *data_size,

  2637. 			uint8_t * buf, int buf_size)

  2638. {

  2639.     MPADecodeContext *s = avctx->priv_data;

  2640.     uint32_t header;

  2641.     int len, out_size;

  2642.     OUT_INT *out_samples = data;

  2643. 

  2644.     len = buf_size;

  2645. 

  2646.     // Discard too short frames

  2647.     if (buf_size < HEADER_SIZE) {

  2648.         *data_size = 0;

  2649.         return buf_size;

  2650.     }

  2651. 

  2652. 

  2653.     if (len > MPA_MAX_CODED_FRAME_SIZE)

  2654.         len = MPA_MAX_CODED_FRAME_SIZE;

  2655. 

  2656.     memcpy(s->inbuf, buf, len);

  2657.     s->inbuf_ptr = s->inbuf + len;

  2658. 

  2659.     // Get header and restore sync word

  2660.     header = (s->inbuf[0] << 24) | (s->inbuf[1] << 16) |

  2661.               (s->inbuf[2] << 8) | s->inbuf[3] | 0xffe00000;

  2662. 

  2663.     if (ff_mpa_check_header(header) < 0) { // Bad header, discard frame

  2664.         *data_size = 0;

  2665.         return buf_size;

  2666.     }

  2667. 

  2668.     decode_header(s, header);

  2669.     /* update codec info */

  2670.     avctx->sample_rate = s->sample_rate;

  2671.     avctx->channels = s->nb_channels;

  2672.     avctx->bit_rate = s->bit_rate;

  2673.     avctx->sub_id = s->layer;

  2674. 

  2675.     avctx->frame_size=s->frame_size = len;

  2676. 

  2677.     if (avctx->parse_only) {

  2678.         /* simply return the frame data */

  2679.         *(uint8_t **)data = s->inbuf;

  2680.         out_size = s->inbuf_ptr - s->inbuf;

  2681.     } else {

  2682.         out_size = mp_decode_frame(s, out_samples);

  2683.     }

  2684. 

  2685.     *data_size = out_size;

  2686.     return buf_size;

  2687. }

  2688. 

  2689. 

  2690. /* Next 3 arrays are indexed by channel config number (passed via codecdata) */

  2691. static int mp3Frames[16] = {0,1,1,2,3,3,4,5,2};   /* number of mp3 decoder instances */

  2692. static int mp3Channels[16] = {0,1,2,3,4,5,6,8,4}; /* total output channels */

  2693. /* offsets into output buffer, assume output order is FL FR BL BR C LFE */

  2694. static int chan_offset[9][5] = {

  2695.     {0},

  2696.     {0},            // C

  2697.     {0},            // FLR

  2698.     {2,0},          // C FLR

  2699.     {2,0,3},        // C FLR BS

  2700.     {4,0,2},        // C FLR BLRS

  2701.     {4,0,2,5},      // C FLR BLRS LFE

  2702.     {4,0,2,6,5},    // C FLR BLRS BLR LFE

  2703.     {0,2}           // FLR BLRS

  2704. };

  2705. 

  2706. 

  2707. static int decode_init_mp3on4(AVCodecContext * avctx)

  2708. {

  2709.     MP3On4DecodeContext *s = avctx->priv_data;

  2710.     int i;

  2711. 

  2712.     if ((avctx->extradata_size < 2) || (avctx->extradata == NULL)) {

  2713.         av_log(avctx, AV_LOG_ERROR, "Codec extradata missing or too short.\n");

  2714.         return -1;

  2715.     }

  2716. 

  2717.     s->chan_cfg = (((unsigned char *)avctx->extradata)[1] >> 3) & 0x0f;

  2718.     s->frames = mp3Frames[s->chan_cfg];

  2719.     if(!s->frames) {

  2720.         av_log(avctx, AV_LOG_ERROR, "Invalid channel config number.\n");

  2721.         return -1;

  2722.     }

  2723.     avctx->channels = mp3Channels[s->chan_cfg];

  2724. 

  2725.     /* Init the first mp3 decoder in standard way, so that all tables get builded

  2726.      * We replace avctx->priv_data with the context of the first decoder so that

  2727.      * decode_init() does not have to be changed.

  2728.      * Other decoders will be inited here copying data from the first context

  2729.      */

  2730.     // Allocate zeroed memory for the first decoder context

  2731.     s->mp3decctx[0] = av_mallocz(sizeof(MPADecodeContext));

  2732.     // Put decoder context in place to make init_decode() happy

  2733.     avctx->priv_data = s->mp3decctx[0];

  2734.     decode_init(avctx);

  2735.     // Restore mp3on4 context pointer

  2736.     avctx->priv_data = s;

  2737.     s->mp3decctx[0]->adu_mode = 1; // Set adu mode

  2738. 

  2739.     /* Create a separate codec/context for each frame (first is already ok).

  2740.      * Each frame is 1 or 2 channels - up to 5 frames allowed

  2741.      */

  2742.     for (i = 1; i < s->frames; i++) {

  2743.         s->mp3decctx[i] = av_mallocz(sizeof(MPADecodeContext));

  2744.         s->mp3decctx[i]->compute_antialias = s->mp3decctx[0]->compute_antialias;

  2745.         s->mp3decctx[i]->inbuf = &s->mp3decctx[i]->inbuf1[0][BACKSTEP_SIZE];

  2746.         s->mp3decctx[i]->inbuf_ptr = s->mp3decctx[i]->inbuf;

  2747.         s->mp3decctx[i]->adu_mode = 1;

  2748.     }

  2749. 

  2750.     return 0;

  2751. }

  2752. 

  2753. 

  2754. static int decode_close_mp3on4(AVCodecContext * avctx)

  2755. {

  2756.     MP3On4DecodeContext *s = avctx->priv_data;

  2757.     int i;

  2758. 

  2759.     for (i = 0; i < s->frames; i++)

  2760.         if (s->mp3decctx[i])

  2761.             av_free(s->mp3decctx[i]);

  2762. 

  2763.     return 0;

  2764. }

  2765. 

  2766. 

  2767. static int decode_frame_mp3on4(AVCodecContext * avctx,

  2768. 			void *data, int *data_size,

  2769. 			uint8_t * buf, int buf_size)

  2770. {

  2771.     MP3On4DecodeContext *s = avctx->priv_data;

  2772.     MPADecodeContext *m;

  2773.     int len, out_size = 0;

  2774.     uint32_t header;

  2775.     OUT_INT *out_samples = data;

  2776.     OUT_INT decoded_buf[MPA_FRAME_SIZE * MPA_MAX_CHANNELS];

  2777.     OUT_INT *outptr, *bp;

  2778.     int fsize;

  2779.     unsigned char *start2 = buf, *start;

  2780.     int fr, i, j, n;

  2781.     int off = avctx->channels;

  2782.     int *coff = chan_offset[s->chan_cfg];

  2783. 

  2784.     len = buf_size;

  2785. 

  2786.     // Discard too short frames

  2787.     if (buf_size < HEADER_SIZE) {

  2788.         *data_size = 0;

  2789.         return buf_size;

  2790.     }

  2791. 

  2792.     // If only one decoder interleave is not needed

  2793.     outptr = s->frames == 1 ? out_samples : decoded_buf;

  2794. 

  2795.     for (fr = 0; fr < s->frames; fr++) {

  2796.         start = start2;

  2797.         fsize = (start[0] << 4) | (start[1] >> 4);

  2798.         start2 += fsize;

  2799.         if (fsize > len)

  2800.             fsize = len;

  2801.         len -= fsize;

  2802.         if (fsize > MPA_MAX_CODED_FRAME_SIZE)

  2803.             fsize = MPA_MAX_CODED_FRAME_SIZE;

  2804.         m = s->mp3decctx[fr];

  2805.         assert (m != NULL);

  2806.         /* copy original to new */

  2807.         m->inbuf_ptr = m->inbuf + fsize;

  2808.         memcpy(m->inbuf, start, fsize);

  2809. 

  2810.         // Get header

  2811.         header = (m->inbuf[0] << 24) | (m->inbuf[1] << 16) |

  2812.                   (m->inbuf[2] << 8) | m->inbuf[3] | 0xfff00000;

  2813. 

  2814.         if (ff_mpa_check_header(header) < 0) { // Bad header, discard block

  2815.             *data_size = 0;

  2816.             return buf_size;

  2817.         }

  2818. 

  2819.         decode_header(m, header);

  2820.         mp_decode_frame(m, decoded_buf);

  2821. 

  2822.         n = MPA_FRAME_SIZE * m->nb_channels;

  2823.         out_size += n * sizeof(OUT_INT);

  2824.         if(s->frames > 1) {

  2825.             /* interleave output data */

  2826.             bp = out_samples + coff[fr];

  2827.             if(m->nb_channels == 1) {

  2828.                 for(j = 0; j < n; j++) {

  2829.                     *bp = decoded_buf[j];

  2830.                     bp += off;

  2831.                 }

  2832.             } else {

  2833.                 for(j = 0; j < n; j++) {

  2834.                     bp[0] = decoded_buf[j++];

  2835.                     bp[1] = decoded_buf[j];

  2836.                     bp += off;

  2837.                 }

  2838.             }

  2839.         }

  2840.     }

  2841. 

  2842.     /* update codec info */

  2843.     avctx->sample_rate = s->mp3decctx[0]->sample_rate;

  2844.     avctx->frame_size= buf_size;

  2845.     avctx->bit_rate = 0;

  2846.     for (i = 0; i < s->frames; i++)

  2847.         avctx->bit_rate += s->mp3decctx[i]->bit_rate;

  2848. 

  2849.     *data_size = out_size;

  2850.     return buf_size;

  2851. }

  2852. 

  2853. 

  2854. AVCodec mp2_decoder =

  2855. {

  2856.     "mp2",

  2857.     CODEC_TYPE_AUDIO,

  2858.     CODEC_ID_MP2,

  2859.     sizeof(MPADecodeContext),

  2860.     decode_init,

  2861.     NULL,

  2862.     NULL,

  2863.     decode_frame,

  2864.     CODEC_CAP_PARSE_ONLY,

  2865. };

  2866. 

  2867. AVCodec mp3_decoder =

  2868. {

  2869.     "mp3",

  2870.     CODEC_TYPE_AUDIO,

  2871.     CODEC_ID_MP3,

  2872.     sizeof(MPADecodeContext),

  2873.     decode_init,

  2874.     NULL,

  2875.     NULL,

  2876.     decode_frame,

  2877.     CODEC_CAP_PARSE_ONLY,

  2878. };

  2879. 

  2880. AVCodec mp3adu_decoder =

  2881. {

  2882.     "mp3adu",

  2883.     CODEC_TYPE_AUDIO,

  2884.     CODEC_ID_MP3ADU,

  2885.     sizeof(MPADecodeContext),

  2886.     decode_init,

  2887.     NULL,

  2888.     NULL,

  2889.     decode_frame_adu,

  2890.     CODEC_CAP_PARSE_ONLY,

  2891. };

  2892. 

  2893. AVCodec mp3on4_decoder =

  2894. {

  2895.     "mp3on4",

  2896.     CODEC_TYPE_AUDIO,

  2897.     CODEC_ID_MP3ON4,

  2898.     sizeof(MP3On4DecodeContext),

  2899.     decode_init_mp3on4,

  2900.     NULL,

  2901.     decode_close_mp3on4,

  2902.     decode_frame_mp3on4,

  2903.     0

  2904. };