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FFmpeg/libavcodec/mpegaudiodec.c

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  1. /*

  2.  * MPEG Audio decoder

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

  4.  *

  5.  * This 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 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 "dsputil.h"

  29. 

  30. /*

  31.  * TODO:

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

  33.  *  - test lsf / mpeg25 extensively.

  34.  */

  35. 

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

  37.    audio decoder */

  38. #ifdef CONFIG_MPEGAUDIO_HP

  39. #   define USE_HIGHPRECISION

  40. #endif

  41. 

  42. #include "mpegaudio.h"

  43. 

  44. #define FRAC_ONE    (1 << FRAC_BITS)

  45. 

  46. #ifdef ARCH_X86

  47. #   define MULL(ra, rb) \

  48.         ({ int rt, dummy; asm (\

  49.             "imull %3               \n\t"\

  50.             "shrdl %4, %%edx, %%eax \n\t"\

  51.             : "=a"(rt), "=d"(dummy)\

  52.             : "a" (ra), "rm" (rb), "i"(FRAC_BITS));\

  53.          rt; })

  54. #   define MUL64(ra, rb) \

  55.         ({ int64_t rt; asm ("imull %2\n\t" : "=A"(rt) : "a" (ra), "g" (rb)); rt; })

  56. #   define MULH(ra, rb) \

  57.         ({ int rt, dummy; asm ("imull %3\n\t" : "=d"(rt), "=a"(dummy): "a" (ra), "rm" (rb)); rt; })

  58. #elif defined(ARCH_ARMV4L)

  59. #   define MULL(a, b) \

  60.         ({  int lo, hi;\

  61.             asm("smull %0, %1, %2, %3     \n\t"\

  62.                 "mov   %0, %0,     lsr %4\n\t"\

  63.                 "add   %1, %0, %1, lsl %5\n\t"\

  64.             : "=&r"(lo), "=&r"(hi)\

  65.             : "r"(b), "r"(a), "i"(FRAC_BITS), "i"(32-FRAC_BITS));\

  66.          hi; })

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

  68. #   define MULH(a, b) ({ int lo, hi; asm ("smull %0, %1, %2, %3" : "=&r"(lo), "=&r"(hi) : "r"(b), "r"(a)); hi; })

  69. #else

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

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

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

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

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

  75. }

  76. #endif

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

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

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

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

  81. 

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

  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 VLC huff_quad_vlc[2];

  170. /* computed from band_size_long */

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

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

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

  174. static int8_t  *table_4_3_exp;

  175. static uint32_t *table_4_3_value;

  176. /* intensity stereo coef table */

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

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

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

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

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

  182. 

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

  184. static uint16_t scale_factor_modshift[64];

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

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

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

  188. 

  189. #define SCALE_GEN(v) \

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

  191. 

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

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

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

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

  196. };

  197. 

  198. void ff_mpa_synth_init(MPA_INT *window);

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

  200. 

  201. /* layer 1 unscaling */

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

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

  204. {

  205.     int shift, mod;

  206.     int64_t val;

  207. 

  208.     shift = scale_factor_modshift[scale_factor];

  209.     mod = shift & 3;

  210.     shift >>= 2;

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

  212.     shift += n;

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

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

  215. }

  216. 

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

  218. {

  219.     int shift, mod, val;

  220. 

  221.     shift = scale_factor_modshift[scale_factor];

  222.     mod = shift & 3;

  223.     shift >>= 2;

  224. 

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

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

  227.     if (shift > 0)

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

  229.     return val;

  230. }

  231. 

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

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

  234. {

  235.     unsigned int m;

  236.     int e;

  237. 

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

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

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

  241.     assert(e>=1);

  242.     if (e > 31)

  243.         return 0;

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

  245. 

  246.     return m;

  247. }

  248. 

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

  250. #define DEV_ORDER 13

  251. 

  252. #define POW_FRAC_BITS 24

  253. #define POW_FRAC_ONE    (1 << POW_FRAC_BITS)

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

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

  256. 

  257. static int dev_4_3_coefs[DEV_ORDER];

  258. 

  259. #if 0 /* unused */

  260. static int pow_mult3[3] = {

  261.     POW_FIX(1.0),

  262.     POW_FIX(1.25992104989487316476),

  263.     POW_FIX(1.58740105196819947474),

  264. };

  265. #endif

  266. 

  267. static void int_pow_init(void)

  268. {

  269.     int i, a;

  270. 

  271.     a = POW_FIX(1.0);

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

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

  274.         dev_4_3_coefs[i] = a;

  275.     }

  276. }

  277. 

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

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

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

  281. {

  282.     int e, er, eq, j;

  283.     int a, a1;

  284. 

  285.     /* renormalize */

  286.     a = i;

  287.     e = POW_FRAC_BITS;

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

  289.         a = a << 1;

  290.         e--;

  291.     }

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

  293.     a1 = 0;

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

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

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

  297.     /* exponent compute (exact) */

  298.     e = e * 4;

  299.     er = e % 3;

  300.     eq = e / 3;

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

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

  303.         a = a >> 1;

  304.         eq++;

  305.     }

  306.     /* convert to float */

  307.     while (a < POW_FRAC_ONE) {

  308.         a = a << 1;

  309.         eq--;

  310.     }

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

  312. #if POW_FRAC_BITS > FRAC_BITS

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

  314.     /* correct overflow */

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

  316.         a = a >> 1;

  317.         eq++;

  318.     }

  319. #endif

  320.     *exp_ptr = eq;

  321.     return a;

  322. }

  323. #endif

  324. 

  325. static int decode_init(AVCodecContext * avctx)

  326. {

  327.     MPADecodeContext *s = avctx->priv_data;

  328.     static int init=0;

  329.     int i, j, k;

  330. 

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

  332.     avctx->sample_fmt= SAMPLE_FMT_S32;

  333. #else

  334.     avctx->sample_fmt= SAMPLE_FMT_S16;

  335. #endif

  336. 

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

  338.         s->compute_antialias= compute_antialias_integer;

  339.     else

  340.         s->compute_antialias= compute_antialias_float;

  341. 

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

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

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

  345.             int shift, mod;

  346.             /* 1.0 (i = 3) is normalized to 2 ^ FRAC_BITS */

  347.             shift = (i / 3);

  348.             mod = i % 3;

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

  350.         }

  351. 

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

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

  354.             int n, norm;

  355.             n = i + 2;

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

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

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

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

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

  361.                     i, norm,

  362.                     scale_factor_mult[i][0],

  363.                     scale_factor_mult[i][1],

  364.                     scale_factor_mult[i][2]);

  365.         }

  366. 

  367.         ff_mpa_synth_init(window);

  368. 

  369.         /* huffman decode tables */

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

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

  372.             int xsize, x, y;

  373.             unsigned int n;

  374.             uint8_t tmp_bits [256];

  375.             uint16_t tmp_codes[256];

  376. 

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

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

  379. 

  380.             xsize = h->xsize;

  381.             n = xsize * xsize;

  382. 

  383.             j = 0;

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

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

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

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

  388.                 }

  389.             }

  390. 

  391.             /* XXX: fail test */

  392.             init_vlc(&huff_vlc[i], 8, 256,

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

  394.         }

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

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

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

  398.         }

  399. 

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

  401.             k = 0;

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

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

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

  405.             }

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

  407.         }

  408. 

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

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

  411.         if(!table_4_3_exp)

  412.             return -1;

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

  414.         if(!table_4_3_value)

  415.             return -1;

  416. 

  417.         int_pow_init();

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

  419.             double f, fm;

  420.             int e, m;

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

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

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

  424.             e+= FRAC_BITS - 31 + 5;

  425. 

  426.             /* normalized to FRAC_BITS */

  427.             table_4_3_value[i] = m;

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

  429.             table_4_3_exp[i] = -e;

  430.         }

  431. 

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

  433.             float f;

  434.             int v;

  435.             if (i != 6) {

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

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

  438.             } else {

  439.                 v = FIXR(1.0);

  440.             }

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

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

  443.         }

  444.         /* invalid values */

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

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

  447. 

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

  449.             double f;

  450.             int e, k;

  451. 

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

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

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

  455.                 k = i & 1;

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

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

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

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

  460.             }

  461.         }

  462. 

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

  464.             float ci, cs, ca;

  465.             ci = ci_table[i];

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

  467.             ca = cs * ci;

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

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

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

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

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

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

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

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

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

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

  478.         }

  479. 

  480.         /* compute mdct windows */

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

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

  483.                 double d;

  484. 

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

  486.                     continue;

  487. 

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

  489.                 if(j==1){

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

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

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

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

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

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

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

  497.                 }

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

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

  500. 

  501.                 if(j==2)

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

  503.                 else

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

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

  506.             }

  507.         }

  508. 

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

  510.            the sign of the right window coefs */

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

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

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

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

  515.             }

  516.         }

  517. 

  518. #if defined(DEBUG)

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

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

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

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

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

  524.         }

  525. #endif

  526.         init = 1;

  527.     }

  528. 

  529.     s->inbuf_index = 0;

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

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

  532. #ifdef DEBUG

  533.     s->frame_count = 0;

  534. #endif

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

  536.         s->adu_mode = 1;

  537.     return 0;

  538. }

  539. 

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

  541. 

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

  543. 

  544. #define COS0_0  FIXHR(0.50060299823519630134/2)

  545. #define COS0_1  FIXHR(0.50547095989754365998/2)

  546. #define COS0_2  FIXHR(0.51544730992262454697/2)

  547. #define COS0_3  FIXHR(0.53104259108978417447/2)

  548. #define COS0_4  FIXHR(0.55310389603444452782/2)

  549. #define COS0_5  FIXHR(0.58293496820613387367/2)

  550. #define COS0_6  FIXHR(0.62250412303566481615/2)

  551. #define COS0_7  FIXHR(0.67480834145500574602/2)

  552. #define COS0_8  FIXHR(0.74453627100229844977/2)

  553. #define COS0_9  FIXHR(0.83934964541552703873/2)

  554. #define COS0_10 FIXHR(0.97256823786196069369/2)

  555. #define COS0_11 FIXHR(1.16943993343288495515/4)

  556. #define COS0_12 FIXHR(1.48416461631416627724/4)

  557. #define COS0_13 FIXHR(2.05778100995341155085/8)

  558. #define COS0_14 FIXHR(3.40760841846871878570/8)

  559. #define COS0_15 FIXHR(10.19000812354805681150/32)

  560. 

  561. #define COS1_0 FIXHR(0.50241928618815570551/2)

  562. #define COS1_1 FIXHR(0.52249861493968888062/2)

  563. #define COS1_2 FIXHR(0.56694403481635770368/2)

  564. #define COS1_3 FIXHR(0.64682178335999012954/2)

  565. #define COS1_4 FIXHR(0.78815462345125022473/2)

  566. #define COS1_5 FIXHR(1.06067768599034747134/4)

  567. #define COS1_6 FIXHR(1.72244709823833392782/4)

  568. #define COS1_7 FIXHR(5.10114861868916385802/16)

  569. 

  570. #define COS2_0 FIXHR(0.50979557910415916894/2)

  571. #define COS2_1 FIXHR(0.60134488693504528054/2)

  572. #define COS2_2 FIXHR(0.89997622313641570463/2)

  573. #define COS2_3 FIXHR(2.56291544774150617881/8)

  574. 

  575. #define COS3_0 FIXHR(0.54119610014619698439/2)

  576. #define COS3_1 FIXHR(1.30656296487637652785/4)

  577. 

  578. #define COS4_0 FIXHR(0.70710678118654752439/2)

  579. 

  580. /* butterfly operator */

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

  582. {\

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

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

  585.     tab[a] = tmp0;\

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

  587. }

  588. 

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

  590. {\

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

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

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

  594. }

  595. 

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

  597. {\

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

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

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

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

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

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

  604. }

  605. 

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

  607. 

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

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

  610. {

  611.     int tmp0, tmp1;

  612. 

  613.     /* pass 1 */

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

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

  616.     /* pass 2 */

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

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

  619.     /* pass 1 */

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

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

  622.     /* pass 2 */

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

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

  625.     /* pass 3 */

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

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

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

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

  630.     /* pass 1 */

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

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

  633.     /* pass 2 */

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

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

  636.     /* pass 1 */

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

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

  639.     /* pass 2 */

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

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

  642.     /* pass 3 */

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

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

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

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

  647.     /* pass 4 */

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

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

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

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

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

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

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

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

  656. 

  657. 

  658. 

  659.     /* pass 1 */

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

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

  662.     /* pass 2 */

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

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

  665.     /* pass 1 */

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

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

  668.     /* pass 2 */

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

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

  671.     /* pass 3 */

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

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

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

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

  676. 

  677.     /* pass 1 */

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

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

  680.     /* pass 2 */

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

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

  683.     /* pass 1 */

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

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

  686.     /* pass 2 */

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

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

  689.     /* pass 3 */

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

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

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

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

  694.     /* pass 4 */

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

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

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

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

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

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

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

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

  703. 

  704.     /* pass 5 */

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

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

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

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

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

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

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

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

  713. 

  714.     /* pass 6 */

  715. 

  716.     ADD( 8, 12);

  717.     ADD(12, 10);

  718.     ADD(10, 14);

  719.     ADD(14,  9);

  720.     ADD( 9, 13);

  721.     ADD(13, 11);

  722.     ADD(11, 15);

  723. 

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  740. 

  741.     ADD(24, 28);

  742.     ADD(28, 26);

  743.     ADD(26, 30);

  744.     ADD(30, 25);

  745.     ADD(25, 29);

  746.     ADD(29, 27);

  747.     ADD(27, 31);

  748. 

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  765. }

  766. 

  767. #if FRAC_BITS <= 15

  768. 

  769. static inline int round_sample(int *sum)

  770. {

  771.     int sum1;

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

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

  774.     if (sum1 < OUT_MIN)

  775.         sum1 = OUT_MIN;

  776.     else if (sum1 > OUT_MAX)

  777.         sum1 = OUT_MAX;

  778.     return sum1;

  779. }

  780. 

  781. #   if defined(ARCH_POWERPC_405)

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

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

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

  785. 

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

  787. #       define MULS(ra, rb) \

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

  789. #   else

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

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

  792. 

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

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

  795. #   endif

  796. #else

  797. 

  798. static inline int round_sample(int64_t *sum)

  799. {

  800.     int sum1;

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

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

  803.     if (sum1 < OUT_MIN)

  804.         sum1 = OUT_MIN;

  805.     else if (sum1 > OUT_MAX)

  806.         sum1 = OUT_MAX;

  807.     return sum1;

  808. }

  809. 

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

  811. #endif

  812. 

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

  814. {                                               \

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

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

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

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

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

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

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

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

  823. }

  824. 

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

  826. {                                               \

  827.     int tmp;\

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  852. }

  853. 

  854. void ff_mpa_synth_init(MPA_INT *window)

  855. {

  856.     int i;

  857. 

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

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

  860.         int v;

  861.         v = mpa_enwindow[i];

  862. #if WFRAC_BITS < 16

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

  864. #endif

  865.         window[i] = v;

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

  867.             v = -v;

  868.         if (i != 0)

  869.             window[512 - i] = v;

  870.     }

  871. }

  872. 

  873. /* 32 sub band synthesis filter. Input: 32 sub band samples, Output:

  874.    32 samples. */

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

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

  877.                          MPA_INT *window, int *dither_state,

  878.                          OUT_INT *samples, int incr,

  879.                          int32_t sb_samples[SBLIMIT])

  880. {

  881.     int32_t tmp[32];

  882.     register MPA_INT *synth_buf;

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

  884.     int j, offset, v;

  885.     OUT_INT *samples2;

  886. #if FRAC_BITS <= 15

  887.     int sum, sum2;

  888. #else

  889.     int64_t sum, sum2;

  890. #endif

  891. 

  892.     dct32(tmp, sb_samples);

  893. 

  894.     offset = *synth_buf_offset;

  895.     synth_buf = synth_buf_ptr + offset;

  896. 

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

  898.         v = tmp[j];

  899. #if FRAC_BITS <= 15

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

  901.            sound */

  902.         if (v > 32767)

  903.             v = 32767;

  904.         else if (v < -32768)

  905.             v = -32768;

  906. #endif

  907.         synth_buf[j] = v;

  908.     }

  909.     /* copy to avoid wrap */

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

  911. 

  912.     samples2 = samples + 31 * incr;

  913.     w = window;

  914.     w2 = window + 31;

  915. 

  916.     sum = *dither_state;

  917.     p = synth_buf + 16;

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

  919.     p = synth_buf + 48;

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

  921.     *samples = round_sample(&sum);

  922.     samples += incr;

  923.     w++;

  924. 

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

  926.        access per two sample */

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

  928.         sum2 = 0;

  929.         p = synth_buf + 16 + j;

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

  931.         p = synth_buf + 48 - j;

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

  933. 

  934.         *samples = round_sample(&sum);

  935.         samples += incr;

  936.         sum += sum2;

  937.         *samples2 = round_sample(&sum);

  938.         samples2 -= incr;

  939.         w++;

  940.         w2--;

  941.     }

  942. 

  943.     p = synth_buf + 32;

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

  945.     *samples = round_sample(&sum);

  946.     *dither_state= sum;

  947. 

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

  949.     *synth_buf_offset = offset;

  950. }

  951. 

  952. #define C3 FIXHR(0.86602540378443864676/2)

  953. 

  954. /* 0.5 / cos(pi*(2*i+1)/36) */

  955. static const int icos36[9] = {

  956.     FIXR(0.50190991877167369479),

  957.     FIXR(0.51763809020504152469), //0

  958.     FIXR(0.55168895948124587824),

  959.     FIXR(0.61038729438072803416),

  960.     FIXR(0.70710678118654752439), //1

  961.     FIXR(0.87172339781054900991),

  962.     FIXR(1.18310079157624925896),

  963.     FIXR(1.93185165257813657349), //2

  964.     FIXR(5.73685662283492756461),

  965. };

  966. 

  967. /* 0.5 / cos(pi*(2*i+1)/36) */

  968. static const int icos36h[9] = {

  969.     FIXHR(0.50190991877167369479/2),

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

  971.     FIXHR(0.55168895948124587824/2),

  972.     FIXHR(0.61038729438072803416/2),

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

  974.     FIXHR(0.87172339781054900991/2),

  975.     FIXHR(1.18310079157624925896/4),

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

  977. //    FIXHR(5.73685662283492756461),

  978. };

  979. 

  980. /* 12 points IMDCT. We compute it "by hand" by factorizing obvious

  981.    cases. */

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

  983. {

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

  985. 

  986.     in0= in[0*3];

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

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

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

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

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

  992.     in5 += in3;

  993.     in3 += in1;

  994. 

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

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

  997. 

  998.     t1 = in0 - in4;

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

  1000. 

  1001.     out[ 7]=

  1002.     out[10]= t1 + t2;

  1003.     out[ 1]=

  1004.     out[ 4]= t1 - t2;

  1005. 

  1006.     in0 += in4>>1;

  1007.     in4 = in0 + in2;

  1008.     in5 += 2*in1;

  1009.     in1 = MULH(in5 + in3, icos36h[1]);

  1010.     out[ 8]=

  1011.     out[ 9]= in4 + in1;

  1012.     out[ 2]=

  1013.     out[ 3]= in4 - in1;

  1014. 

  1015.     in0 -= in2;

  1016.     in5 = MULH(2*(in5 - in3), icos36h[7]);

  1017.     out[ 0]=

  1018.     out[ 5]= in0 - in5;

  1019.     out[ 6]=

  1020.     out[11]= in0 + in5;

  1021. }

  1022. 

  1023. /* cos(pi*i/18) */

  1024. #define C1 FIXHR(0.98480775301220805936/2)

  1025. #define C2 FIXHR(0.93969262078590838405/2)

  1026. #define C3 FIXHR(0.86602540378443864676/2)

  1027. #define C4 FIXHR(0.76604444311897803520/2)

  1028. #define C5 FIXHR(0.64278760968653932632/2)

  1029. #define C6 FIXHR(0.5/2)

  1030. #define C7 FIXHR(0.34202014332566873304/2)

  1031. #define C8 FIXHR(0.17364817766693034885/2)

  1032. 

  1033. 

  1034. /* using Lee like decomposition followed by hand coded 9 points DCT */

  1035. static void imdct36(int *out, int *buf, int *in, int *win)

  1036. {

  1037.     int i, j, t0, t1, t2, t3, s0, s1, s2, s3;

  1038.     int tmp[18], *tmp1, *in1;

  1039. 

  1040.     for(i=17;i>=1;i--)

  1041.         in[i] += in[i-1];

  1042.     for(i=17;i>=3;i-=2)

  1043.         in[i] += in[i-2];

  1044. 

  1045.     for(j=0;j<2;j++) {

  1046.         tmp1 = tmp + j;

  1047.         in1 = in + j;

  1048. #if 0

  1049. //more accurate but slower

  1050.         int64_t t0, t1, t2, t3;

  1051.         t2 = in1[2*4] + in1[2*8] - in1[2*2];

  1052. 

  1053.         t3 = (in1[2*0] + (int64_t)(in1[2*6]>>1))<<32;

  1054.         t1 = in1[2*0] - in1[2*6];

  1055.         tmp1[ 6] = t1 - (t2>>1);

  1056.         tmp1[16] = t1 + t2;

  1057. 

  1058.         t0 = MUL64(2*(in1[2*2] + in1[2*4]),    C2);

  1059.         t1 = MUL64(   in1[2*4] - in1[2*8] , -2*C8);

  1060.         t2 = MUL64(2*(in1[2*2] + in1[2*8]),   -C4);

  1061. 

  1062.         tmp1[10] = (t3 - t0 - t2) >> 32;

  1063.         tmp1[ 2] = (t3 + t0 + t1) >> 32;

  1064.         tmp1[14] = (t3 + t2 - t1) >> 32;

  1065. 

  1066.         tmp1[ 4] = MULH(2*(in1[2*5] + in1[2*7] - in1[2*1]), -C3);

  1067.         t2 = MUL64(2*(in1[2*1] + in1[2*5]),    C1);

  1068.         t3 = MUL64(   in1[2*5] - in1[2*7] , -2*C7);

  1069.         t0 = MUL64(2*in1[2*3], C3);

  1070. 

  1071.         t1 = MUL64(2*(in1[2*1] + in1[2*7]),   -C5);

  1072. 

  1073.         tmp1[ 0] = (t2 + t3 + t0) >> 32;

  1074.         tmp1[12] = (t2 + t1 - t0) >> 32;

  1075.         tmp1[ 8] = (t3 - t1 - t0) >> 32;

  1076. #else

  1077.         t2 = in1[2*4] + in1[2*8] - in1[2*2];

  1078. 

  1079.         t3 = in1[2*0] + (in1[2*6]>>1);

  1080.         t1 = in1[2*0] - in1[2*6];

  1081.         tmp1[ 6] = t1 - (t2>>1);

  1082.         tmp1[16] = t1 + t2;

  1083. 

  1084.         t0 = MULH(2*(in1[2*2] + in1[2*4]),    C2);

  1085.         t1 = MULH(   in1[2*4] - in1[2*8] , -2*C8);

  1086.         t2 = MULH(2*(in1[2*2] + in1[2*8]),   -C4);

  1087. 

  1088.         tmp1[10] = t3 - t0 - t2;

  1089.         tmp1[ 2] = t3 + t0 + t1;

  1090.         tmp1[14] = t3 + t2 - t1;

  1091. 

  1092.         tmp1[ 4] = MULH(2*(in1[2*5] + in1[2*7] - in1[2*1]), -C3);

  1093.         t2 = MULH(2*(in1[2*1] + in1[2*5]),    C1);

  1094.         t3 = MULH(   in1[2*5] - in1[2*7] , -2*C7);

  1095.         t0 = MULH(2*in1[2*3], C3);

  1096. 

  1097.         t1 = MULH(2*(in1[2*1] + in1[2*7]),   -C5);

  1098. 

  1099.         tmp1[ 0] = t2 + t3 + t0;

  1100.         tmp1[12] = t2 + t1 - t0;

  1101.         tmp1[ 8] = t3 - t1 - t0;

  1102. #endif

  1103.     }

  1104. 

  1105.     i = 0;

  1106.     for(j=0;j<4;j++) {

  1107.         t0 = tmp[i];

  1108.         t1 = tmp[i + 2];

  1109.         s0 = t1 + t0;

  1110.         s2 = t1 - t0;

  1111. 

  1112.         t2 = tmp[i + 1];

  1113.         t3 = tmp[i + 3];

  1114.         s1 = MULH(2*(t3 + t2), icos36h[j]);

  1115.         s3 = MULL(t3 - t2, icos36[8 - j]);

  1116. 

  1117.         t0 = s0 + s1;

  1118.         t1 = s0 - s1;

  1119.         out[(9 + j)*SBLIMIT] =  MULH(t1, win[9 + j]) + buf[9 + j];

  1120.         out[(8 - j)*SBLIMIT] =  MULH(t1, win[8 - j]) + buf[8 - j];

  1121.         buf[9 + j] = MULH(t0, win[18 + 9 + j]);

  1122.         buf[8 - j] = MULH(t0, win[18 + 8 - j]);

  1123. 

  1124.         t0 = s2 + s3;

  1125.         t1 = s2 - s3;

  1126.         out[(9 + 8 - j)*SBLIMIT] =  MULH(t1, win[9 + 8 - j]) + buf[9 + 8 - j];

  1127.         out[(        j)*SBLIMIT] =  MULH(t1, win[        j]) + buf[        j];

  1128.         buf[9 + 8 - j] = MULH(t0, win[18 + 9 + 8 - j]);

  1129.         buf[      + j] = MULH(t0, win[18         + j]);

  1130.         i += 4;

  1131.     }

  1132. 

  1133.     s0 = tmp[16];

  1134.     s1 = MULH(2*tmp[17], icos36h[4]);

  1135.     t0 = s0 + s1;

  1136.     t1 = s0 - s1;

  1137.     out[(9 + 4)*SBLIMIT] =  MULH(t1, win[9 + 4]) + buf[9 + 4];

  1138.     out[(8 - 4)*SBLIMIT] =  MULH(t1, win[8 - 4]) + buf[8 - 4];

  1139.     buf[9 + 4] = MULH(t0, win[18 + 9 + 4]);

  1140.     buf[8 - 4] = MULH(t0, win[18 + 8 - 4]);

  1141. }

  1142. 

  1143. /* header decoding. MUST check the header before because no

  1144.    consistency check is done there. Return 1 if free format found and

  1145.    that the frame size must be computed externally */

  1146. static int decode_header(MPADecodeContext *s, uint32_t header)

  1147. {

  1148.     int sample_rate, frame_size, mpeg25, padding;

  1149.     int sample_rate_index, bitrate_index;

  1150.     if (header & (1<<20)) {

  1151.         s->lsf = (header & (1<<19)) ? 0 : 1;

  1152.         mpeg25 = 0;

  1153.     } else {

  1154.         s->lsf = 1;

  1155.         mpeg25 = 1;

  1156.     }

  1157. 

  1158.     s->layer = 4 - ((header >> 17) & 3);

  1159.     /* extract frequency */

  1160.     sample_rate_index = (header >> 10) & 3;

  1161.     sample_rate = mpa_freq_tab[sample_rate_index] >> (s->lsf + mpeg25);

  1162.     sample_rate_index += 3 * (s->lsf + mpeg25);

  1163.     s->sample_rate_index = sample_rate_index;

  1164.     s->error_protection = ((header >> 16) & 1) ^ 1;

  1165.     s->sample_rate = sample_rate;

  1166. 

  1167.     bitrate_index = (header >> 12) & 0xf;

  1168.     padding = (header >> 9) & 1;

  1169.     //extension = (header >> 8) & 1;

  1170.     s->mode = (header >> 6) & 3;

  1171.     s->mode_ext = (header >> 4) & 3;

  1172.     //copyright = (header >> 3) & 1;

  1173.     //original = (header >> 2) & 1;

  1174.     //emphasis = header & 3;

  1175. 

  1176.     if (s->mode == MPA_MONO)

  1177.         s->nb_channels = 1;

  1178.     else

  1179.         s->nb_channels = 2;

  1180. 

  1181.     if (bitrate_index != 0) {

  1182.         frame_size = mpa_bitrate_tab[s->lsf][s->layer - 1][bitrate_index];

  1183.         s->bit_rate = frame_size * 1000;

  1184.         switch(s->layer) {

  1185.         case 1:

  1186.             frame_size = (frame_size * 12000) / sample_rate;

  1187.             frame_size = (frame_size + padding) * 4;

  1188.             break;

  1189.         case 2:

  1190.             frame_size = (frame_size * 144000) / sample_rate;

  1191.             frame_size += padding;

  1192.             break;

  1193.         default:

  1194.         case 3:

  1195.             frame_size = (frame_size * 144000) / (sample_rate << s->lsf);

  1196.             frame_size += padding;

  1197.             break;

  1198.         }

  1199.         s->frame_size = frame_size;

  1200.     } else {

  1201.         /* if no frame size computed, signal it */

  1202.         if (!s->free_format_frame_size)

  1203.             return 1;

  1204.         /* free format: compute bitrate and real frame size from the

  1205.            frame size we extracted by reading the bitstream */

  1206.         s->frame_size = s->free_format_frame_size;

  1207.         switch(s->layer) {

  1208.         case 1:

  1209.             s->frame_size += padding  * 4;

  1210.             s->bit_rate = (s->frame_size * sample_rate) / 48000;

  1211.             break;

  1212.         case 2:

  1213.             s->frame_size += padding;

  1214.             s->bit_rate = (s->frame_size * sample_rate) / 144000;

  1215.             break;

  1216.         default:

  1217.         case 3:

  1218.             s->frame_size += padding;

  1219.             s->bit_rate = (s->frame_size * (sample_rate << s->lsf)) / 144000;

  1220.             break;

  1221.         }

  1222.     }

  1223. 

  1224. #if defined(DEBUG)

  1225.     dprintf("layer%d, %d Hz, %d kbits/s, ",

  1226.            s->layer, s->sample_rate, s->bit_rate);

  1227.     if (s->nb_channels == 2) {

  1228.         if (s->layer == 3) {

  1229.             if (s->mode_ext & MODE_EXT_MS_STEREO)

  1230.                 dprintf("ms-");

  1231.             if (s->mode_ext & MODE_EXT_I_STEREO)

  1232.                 dprintf("i-");

  1233.         }

  1234.         dprintf("stereo");

  1235.     } else {

  1236.         dprintf("mono");

  1237.     }

  1238.     dprintf("\n");

  1239. #endif

  1240.     return 0;

  1241. }

  1242. 

  1243. /* useful helper to get mpeg audio stream infos. Return -1 if error in

  1244.    header, otherwise the coded frame size in bytes */

  1245. int mpa_decode_header(AVCodecContext *avctx, uint32_t head)

  1246. {

  1247.     MPADecodeContext s1, *s = &s1;

  1248.     memset( s, 0, sizeof(MPADecodeContext) );

  1249. 

  1250.     if (ff_mpa_check_header(head) != 0)

  1251.         return -1;

  1252. 

  1253.     if (decode_header(s, head) != 0) {

  1254.         return -1;

  1255.     }

  1256. 

  1257.     switch(s->layer) {

  1258.     case 1:

  1259.         avctx->frame_size = 384;

  1260.         break;

  1261.     case 2:

  1262.         avctx->frame_size = 1152;

  1263.         break;

  1264.     default:

  1265.     case 3:

  1266.         if (s->lsf)

  1267.             avctx->frame_size = 576;

  1268.         else

  1269.             avctx->frame_size = 1152;

  1270.         break;

  1271.     }

  1272. 

  1273.     avctx->sample_rate = s->sample_rate;

  1274.     avctx->channels = s->nb_channels;

  1275.     avctx->bit_rate = s->bit_rate;

  1276.     avctx->sub_id = s->layer;

  1277.     return s->frame_size;

  1278. }

  1279. 

  1280. /* return the number of decoded frames */

  1281. static int mp_decode_layer1(MPADecodeContext *s)

  1282. {

  1283.     int bound, i, v, n, ch, j, mant;

  1284.     uint8_t allocation[MPA_MAX_CHANNELS][SBLIMIT];

  1285.     uint8_t scale_factors[MPA_MAX_CHANNELS][SBLIMIT];

  1286. 

  1287.     if (s->mode == MPA_JSTEREO)

  1288.         bound = (s->mode_ext + 1) * 4;

  1289.     else

  1290.         bound = SBLIMIT;

  1291. 

  1292.     /* allocation bits */

  1293.     for(i=0;i<bound;i++) {

  1294.         for(ch=0;ch<s->nb_channels;ch++) {

  1295.             allocation[ch][i] = get_bits(&s->gb, 4);

  1296.         }

  1297.     }

  1298.     for(i=bound;i<SBLIMIT;i++) {

  1299.         allocation[0][i] = get_bits(&s->gb, 4);

  1300.     }

  1301. 

  1302.     /* scale factors */

  1303.     for(i=0;i<bound;i++) {

  1304.         for(ch=0;ch<s->nb_channels;ch++) {

  1305.             if (allocation[ch][i])

  1306.                 scale_factors[ch][i] = get_bits(&s->gb, 6);

  1307.         }

  1308.     }

  1309.     for(i=bound;i<SBLIMIT;i++) {

  1310.         if (allocation[0][i]) {

  1311.             scale_factors[0][i] = get_bits(&s->gb, 6);

  1312.             scale_factors[1][i] = get_bits(&s->gb, 6);

  1313.         }

  1314.     }

  1315. 

  1316.     /* compute samples */

  1317.     for(j=0;j<12;j++) {

  1318.         for(i=0;i<bound;i++) {

  1319.             for(ch=0;ch<s->nb_channels;ch++) {

  1320.                 n = allocation[ch][i];

  1321.                 if (n) {

  1322.                     mant = get_bits(&s->gb, n + 1);

  1323.                     v = l1_unscale(n, mant, scale_factors[ch][i]);

  1324.                 } else {

  1325.                     v = 0;

  1326.                 }

  1327.                 s->sb_samples[ch][j][i] = v;

  1328.             }

  1329.         }

  1330.         for(i=bound;i<SBLIMIT;i++) {

  1331.             n = allocation[0][i];

  1332.             if (n) {

  1333.                 mant = get_bits(&s->gb, n + 1);

  1334.                 v = l1_unscale(n, mant, scale_factors[0][i]);

  1335.                 s->sb_samples[0][j][i] = v;

  1336.                 v = l1_unscale(n, mant, scale_factors[1][i]);

  1337.                 s->sb_samples[1][j][i] = v;

  1338.             } else {

  1339.                 s->sb_samples[0][j][i] = 0;

  1340.                 s->sb_samples[1][j][i] = 0;

  1341.             }

  1342.         }

  1343.     }

  1344.     return 12;

  1345. }

  1346. 

  1347. /* bitrate is in kb/s */

  1348. int l2_select_table(int bitrate, int nb_channels, int freq, int lsf)

  1349. {

  1350.     int ch_bitrate, table;

  1351. 

  1352.     ch_bitrate = bitrate / nb_channels;

  1353.     if (!lsf) {

  1354.         if ((freq == 48000 && ch_bitrate >= 56) ||

  1355.             (ch_bitrate >= 56 && ch_bitrate <= 80))

  1356.             table = 0;

  1357.         else if (freq != 48000 && ch_bitrate >= 96)

  1358.             table = 1;

  1359.         else if (freq != 32000 && ch_bitrate <= 48)

  1360.             table = 2;

  1361.         else

  1362.             table = 3;

  1363.     } else {

  1364.         table = 4;

  1365.     }

  1366.     return table;

  1367. }

  1368. 

  1369. static int mp_decode_layer2(MPADecodeContext *s)

  1370. {

  1371.     int sblimit; /* number of used subbands */

  1372.     const unsigned char *alloc_table;

  1373.     int table, bit_alloc_bits, i, j, ch, bound, v;

  1374.     unsigned char bit_alloc[MPA_MAX_CHANNELS][SBLIMIT];

  1375.     unsigned char scale_code[MPA_MAX_CHANNELS][SBLIMIT];

  1376.     unsigned char scale_factors[MPA_MAX_CHANNELS][SBLIMIT][3], *sf;

  1377.     int scale, qindex, bits, steps, k, l, m, b;

  1378. 

  1379.     /* select decoding table */

  1380.     table = l2_select_table(s->bit_rate / 1000, s->nb_channels,

  1381.                             s->sample_rate, s->lsf);

  1382.     sblimit = sblimit_table[table];

  1383.     alloc_table = alloc_tables[table];

  1384. 

  1385.     if (s->mode == MPA_JSTEREO)

  1386.         bound = (s->mode_ext + 1) * 4;

  1387.     else

  1388.         bound = sblimit;

  1389. 

  1390.     dprintf("bound=%d sblimit=%d\n", bound, sblimit);

  1391. 

  1392.     /* sanity check */

  1393.     if( bound > sblimit ) bound = sblimit;

  1394. 

  1395.     /* parse bit allocation */

  1396.     j = 0;

  1397.     for(i=0;i<bound;i++) {

  1398.         bit_alloc_bits = alloc_table[j];

  1399.         for(ch=0;ch<s->nb_channels;ch++) {

  1400.             bit_alloc[ch][i] = get_bits(&s->gb, bit_alloc_bits);

  1401.         }

  1402.         j += 1 << bit_alloc_bits;

  1403.     }

  1404.     for(i=bound;i<sblimit;i++) {

  1405.         bit_alloc_bits = alloc_table[j];

  1406.         v = get_bits(&s->gb, bit_alloc_bits);

  1407.         bit_alloc[0][i] = v;

  1408.         bit_alloc[1][i] = v;

  1409.         j += 1 << bit_alloc_bits;

  1410.     }

  1411. 

  1412. #ifdef DEBUG

  1413.     {

  1414.         for(ch=0;ch<s->nb_channels;ch++) {

  1415.             for(i=0;i<sblimit;i++)

  1416.                 dprintf(" %d", bit_alloc[ch][i]);

  1417.             dprintf("\n");

  1418.         }

  1419.     }

  1420. #endif

  1421. 

  1422.     /* scale codes */

  1423.     for(i=0;i<sblimit;i++) {

  1424.         for(ch=0;ch<s->nb_channels;ch++) {

  1425.             if (bit_alloc[ch][i])

  1426.                 scale_code[ch][i] = get_bits(&s->gb, 2);

  1427.         }

  1428.     }

  1429. 

  1430.     /* scale factors */

  1431.     for(i=0;i<sblimit;i++) {

  1432.         for(ch=0;ch<s->nb_channels;ch++) {

  1433.             if (bit_alloc[ch][i]) {

  1434.                 sf = scale_factors[ch][i];

  1435.                 switch(scale_code[ch][i]) {

  1436.                 default:

  1437.                 case 0:

  1438.                     sf[0] = get_bits(&s->gb, 6);

  1439.                     sf[1] = get_bits(&s->gb, 6);

  1440.                     sf[2] = get_bits(&s->gb, 6);

  1441.                     break;

  1442.                 case 2:

  1443.                     sf[0] = get_bits(&s->gb, 6);

  1444.                     sf[1] = sf[0];

  1445.                     sf[2] = sf[0];

  1446.                     break;

  1447.                 case 1:

  1448.                     sf[0] = get_bits(&s->gb, 6);

  1449.                     sf[2] = get_bits(&s->gb, 6);

  1450.                     sf[1] = sf[0];

  1451.                     break;

  1452.                 case 3:

  1453.                     sf[0] = get_bits(&s->gb, 6);

  1454.                     sf[2] = get_bits(&s->gb, 6);

  1455.                     sf[1] = sf[2];

  1456.                     break;

  1457.                 }

  1458.             }

  1459.         }

  1460.     }

  1461. 

  1462. #ifdef DEBUG

  1463.     for(ch=0;ch<s->nb_channels;ch++) {

  1464.         for(i=0;i<sblimit;i++) {

  1465.             if (bit_alloc[ch][i]) {

  1466.                 sf = scale_factors[ch][i];

  1467.                 dprintf(" %d %d %d", sf[0], sf[1], sf[2]);

  1468.             } else {

  1469.                 dprintf(" -");

  1470.             }

  1471.         }

  1472.         dprintf("\n");

  1473.     }

  1474. #endif

  1475. 

  1476.     /* samples */

  1477.     for(k=0;k<3;k++) {

  1478.         for(l=0;l<12;l+=3) {

  1479.             j = 0;

  1480.             for(i=0;i<bound;i++) {

  1481.                 bit_alloc_bits = alloc_table[j];

  1482.                 for(ch=0;ch<s->nb_channels;ch++) {

  1483.                     b = bit_alloc[ch][i];

  1484.                     if (b) {

  1485.                         scale = scale_factors[ch][i][k];

  1486.                         qindex = alloc_table[j+b];

  1487.                         bits = quant_bits[qindex];

  1488.                         if (bits < 0) {

  1489.                             /* 3 values at the same time */

  1490.                             v = get_bits(&s->gb, -bits);

  1491.                             steps = quant_steps[qindex];

  1492.                             s->sb_samples[ch][k * 12 + l + 0][i] =

  1493.                                 l2_unscale_group(steps, v % steps, scale);

  1494.                             v = v / steps;

  1495.                             s->sb_samples[ch][k * 12 + l + 1][i] =

  1496.                                 l2_unscale_group(steps, v % steps, scale);

  1497.                             v = v / steps;

  1498.                             s->sb_samples[ch][k * 12 + l + 2][i] =

  1499.                                 l2_unscale_group(steps, v, scale);

  1500.                         } else {

  1501.                             for(m=0;m<3;m++) {

  1502.                                 v = get_bits(&s->gb, bits);

  1503.                                 v = l1_unscale(bits - 1, v, scale);

  1504.                                 s->sb_samples[ch][k * 12 + l + m][i] = v;

  1505.                             }

  1506.                         }

  1507.                     } else {

  1508.                         s->sb_samples[ch][k * 12 + l + 0][i] = 0;

  1509.                         s->sb_samples[ch][k * 12 + l + 1][i] = 0;

  1510.                         s->sb_samples[ch][k * 12 + l + 2][i] = 0;

  1511.                     }

  1512.                 }

  1513.                 /* next subband in alloc table */

  1514.                 j += 1 << bit_alloc_bits;

  1515.             }

  1516.             /* XXX: find a way to avoid this duplication of code */

  1517.             for(i=bound;i<sblimit;i++) {

  1518.                 bit_alloc_bits = alloc_table[j];

  1519.                 b = bit_alloc[0][i];

  1520.                 if (b) {

  1521.                     int mant, scale0, scale1;

  1522.                     scale0 = scale_factors[0][i][k];

  1523.                     scale1 = scale_factors[1][i][k];

  1524.                     qindex = alloc_table[j+b];

  1525.                     bits = quant_bits[qindex];

  1526.                     if (bits < 0) {

  1527.                         /* 3 values at the same time */

  1528.                         v = get_bits(&s->gb, -bits);

  1529.                         steps = quant_steps[qindex];

  1530.                         mant = v % steps;

  1531.                         v = v / steps;

  1532.                         s->sb_samples[0][k * 12 + l + 0][i] =

  1533.                             l2_unscale_group(steps, mant, scale0);

  1534.                         s->sb_samples[1][k * 12 + l + 0][i] =

  1535.                             l2_unscale_group(steps, mant, scale1);

  1536.                         mant = v % steps;

  1537.                         v = v / steps;

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

  1539.                             l2_unscale_group(steps, mant, scale0);

  1540.                         s->sb_samples[1][k * 12 + l + 1][i] =

  1541.                             l2_unscale_group(steps, mant, scale1);

  1542.                         s->sb_samples[0][k * 12 + l + 2][i] =

  1543.                             l2_unscale_group(steps, v, scale0);

  1544.                         s->sb_samples[1][k * 12 + l + 2][i] =

  1545.                             l2_unscale_group(steps, v, scale1);

  1546.                     } else {

  1547.                         for(m=0;m<3;m++) {

  1548.                             mant = get_bits(&s->gb, bits);

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

  1550.                                 l1_unscale(bits - 1, mant, scale0);

  1551.                             s->sb_samples[1][k * 12 + l + m][i] =

  1552.                                 l1_unscale(bits - 1, mant, scale1);

  1553.                         }

  1554.                     }

  1555.                 } else {

  1556.                     s->sb_samples[0][k * 12 + l + 0][i] = 0;

  1557.                     s->sb_samples[0][k * 12 + l + 1][i] = 0;

  1558.                     s->sb_samples[0][k * 12 + l + 2][i] = 0;

  1559.                     s->sb_samples[1][k * 12 + l + 0][i] = 0;

  1560.                     s->sb_samples[1][k * 12 + l + 1][i] = 0;

  1561.                     s->sb_samples[1][k * 12 + l + 2][i] = 0;

  1562.                 }

  1563.                 /* next subband in alloc table */

  1564.                 j += 1 << bit_alloc_bits;

  1565.             }

  1566.             /* fill remaining samples to zero */

  1567.             for(i=sblimit;i<SBLIMIT;i++) {

  1568.                 for(ch=0;ch<s->nb_channels;ch++) {

  1569.                     s->sb_samples[ch][k * 12 + l + 0][i] = 0;

  1570.                     s->sb_samples[ch][k * 12 + l + 1][i] = 0;

  1571.                     s->sb_samples[ch][k * 12 + l + 2][i] = 0;

  1572.                 }

  1573.             }

  1574.         }

  1575.     }

  1576.     return 3 * 12;

  1577. }

  1578. 

  1579. /*

  1580.  * Seek back in the stream for backstep bytes (at most 511 bytes)

  1581.  */

  1582. static void seek_to_maindata(MPADecodeContext *s, unsigned int backstep)

  1583. {

  1584.     uint8_t *ptr;

  1585. 

  1586.     /* compute current position in stream */

  1587.     ptr = (uint8_t *)(s->gb.buffer + (get_bits_count(&s->gb)>>3));

  1588. 

  1589.     /* copy old data before current one */

  1590.     ptr -= backstep;

  1591.     memcpy(ptr, s->inbuf1[s->inbuf_index ^ 1] +

  1592.            BACKSTEP_SIZE + s->old_frame_size - backstep, backstep);

  1593.     /* init get bits again */

  1594.     init_get_bits(&s->gb, ptr, (s->frame_size + backstep)*8);

  1595. 

  1596.     /* prepare next buffer */

  1597.     s->inbuf_index ^= 1;

  1598.     s->inbuf = &s->inbuf1[s->inbuf_index][BACKSTEP_SIZE];

  1599.     s->old_frame_size = s->frame_size;

  1600. }

  1601. 

  1602. static inline void lsf_sf_expand(int *slen,

  1603.                                  int sf, int n1, int n2, int n3)

  1604. {

  1605.     if (n3) {

  1606.         slen[3] = sf % n3;

  1607.         sf /= n3;

  1608.     } else {

  1609.         slen[3] = 0;

  1610.     }

  1611.     if (n2) {

  1612.         slen[2] = sf % n2;

  1613.         sf /= n2;

  1614.     } else {

  1615.         slen[2] = 0;

  1616.     }

  1617.     slen[1] = sf % n1;

  1618.     sf /= n1;

  1619.     slen[0] = sf;

  1620. }

  1621. 

  1622. static void exponents_from_scale_factors(MPADecodeContext *s,

  1623.                                          GranuleDef *g,

  1624.                                          int16_t *exponents)

  1625. {

  1626.     const uint8_t *bstab, *pretab;

  1627.     int len, i, j, k, l, v0, shift, gain, gains[3];

  1628.     int16_t *exp_ptr;

  1629. 

  1630.     exp_ptr = exponents;

  1631.     gain = g->global_gain - 210;

  1632.     shift = g->scalefac_scale + 1;

  1633. 

  1634.     bstab = band_size_long[s->sample_rate_index];

  1635.     pretab = mpa_pretab[g->preflag];

  1636.     for(i=0;i<g->long_end;i++) {

  1637.         v0 = gain - ((g->scale_factors[i] + pretab[i]) << shift);

  1638.         len = bstab[i];

  1639.         for(j=len;j>0;j--)

  1640.             *exp_ptr++ = v0;

  1641.     }

  1642. 

  1643.     if (g->short_start < 13) {

  1644.         bstab = band_size_short[s->sample_rate_index];

  1645.         gains[0] = gain - (g->subblock_gain[0] << 3);

  1646.         gains[1] = gain - (g->subblock_gain[1] << 3);

  1647.         gains[2] = gain - (g->subblock_gain[2] << 3);

  1648.         k = g->long_end;

  1649.         for(i=g->short_start;i<13;i++) {

  1650.             len = bstab[i];

  1651.             for(l=0;l<3;l++) {

  1652.                 v0 = gains[l] - (g->scale_factors[k++] << shift);

  1653.                 for(j=len;j>0;j--)

  1654.                 *exp_ptr++ = v0;

  1655.             }

  1656.         }

  1657.     }

  1658. }

  1659. 

  1660. /* handle n = 0 too */

  1661. static inline int get_bitsz(GetBitContext *s, int n)

  1662. {

  1663.     if (n == 0)

  1664.         return 0;

  1665.     else

  1666.         return get_bits(s, n);

  1667. }

  1668. 

  1669. static int huffman_decode(MPADecodeContext *s, GranuleDef *g,

  1670.                           int16_t *exponents, int end_pos)

  1671. {

  1672.     int s_index;

  1673.     int linbits, code, x, y, l, v, i, j, k, pos;

  1674.     int last_pos;

  1675.     VLC *vlc;

  1676. 

  1677.     /* low frequencies (called big values) */

  1678.     s_index = 0;

  1679.     for(i=0;i<3;i++) {

  1680.         j = g->region_size[i];

  1681.         if (j == 0)

  1682.             continue;

  1683.         /* select vlc table */

  1684.         k = g->table_select[i];

  1685.         l = mpa_huff_data[k][0];

  1686.         linbits = mpa_huff_data[k][1];

  1687.         vlc = &huff_vlc[l];

  1688. 

  1689.         if(!l){

  1690.             memset(&g->sb_hybrid[s_index], 0, sizeof(*g->sb_hybrid)*j);

  1691.             s_index += 2*j;

  1692.             continue;

  1693.         }

  1694. 

  1695.         /* read huffcode and compute each couple */

  1696.         for(;j>0;j--) {

  1697.             if (get_bits_count(&s->gb) >= end_pos)

  1698.                 break;

  1699.             y = get_vlc2(&s->gb, vlc->table, 8, 3);

  1700. 

  1701.             if(!y){

  1702.                 g->sb_hybrid[s_index  ] =

  1703.                 g->sb_hybrid[s_index+1] = 0;

  1704.                 s_index += 2;

  1705.                 continue;

  1706.             }

  1707. 

  1708.             x = y >> 4;

  1709.             y = y & 0x0f;

  1710. 

  1711.             dprintf("region=%d n=%d x=%d y=%d exp=%d\n",

  1712.                     i, g->region_size[i] - j, x, y, exponents[s_index]);

  1713.             if (x) {

  1714.                 if (x == 15)

  1715.                     x += get_bitsz(&s->gb, linbits);

  1716.                 v = l3_unscale(x, exponents[s_index]);

  1717.                 if (get_bits1(&s->gb))

  1718.                     v = -v;

  1719.             } else {

  1720.                 v = 0;

  1721.             }

  1722.             g->sb_hybrid[s_index++] = v;

  1723.             if (y) {

  1724.                 if (y == 15)

  1725.                     y += get_bitsz(&s->gb, linbits);

  1726.                 v = l3_unscale(y, exponents[s_index]);

  1727.                 if (get_bits1(&s->gb))

  1728.                     v = -v;

  1729.             } else {

  1730.                 v = 0;

  1731.             }

  1732.             g->sb_hybrid[s_index++] = v;

  1733.         }

  1734.     }

  1735. 

  1736.     /* high frequencies */

  1737.     vlc = &huff_quad_vlc[g->count1table_select];

  1738.     last_pos=0;

  1739.     while (s_index <= 572) {

  1740.         pos = get_bits_count(&s->gb);

  1741.         if (pos >= end_pos) {

  1742.             if (pos > end_pos && last_pos){

  1743.                 /* some encoders generate an incorrect size for this

  1744.                    part. We must go back into the data */

  1745.                 s_index -= 4;

  1746.                 init_get_bits(&s->gb, s->gb.buffer + (last_pos>>3), s->gb.size_in_bits - (last_pos&(~7)));

  1747.                 skip_bits(&s->gb, last_pos&7);

  1748.             }

  1749.             break;

  1750.         }

  1751.         last_pos= pos;

  1752. 

  1753.         code = get_vlc2(&s->gb, vlc->table, vlc->bits, 1);

  1754.         dprintf("t=%d code=%d\n", g->count1table_select, code);

  1755.         g->sb_hybrid[s_index+0]=

  1756.         g->sb_hybrid[s_index+1]=

  1757.         g->sb_hybrid[s_index+2]=

  1758.         g->sb_hybrid[s_index+3]= 0;

  1759.         while(code){

  1760.             const static int idxtab[16]={3,3,2,2,1,1,1,1,0,0,0,0,0,0,0,0};

  1761.             int pos= s_index+idxtab[code];

  1762.             code ^= 8>>idxtab[code];

  1763.             v = l3_unscale(1, exponents[pos]);

  1764.             if(get_bits1(&s->gb))

  1765.                 v = -v;

  1766.             g->sb_hybrid[pos] = v;

  1767.         }

  1768.         s_index+=4;

  1769.     }

  1770.     memset(&g->sb_hybrid[s_index], 0, sizeof(*g->sb_hybrid)*(576 - s_index));

  1771.     return 0;

  1772. }

  1773. 

  1774. /* Reorder short blocks from bitstream order to interleaved order. It

  1775.    would be faster to do it in parsing, but the code would be far more

  1776.    complicated */

  1777. static void reorder_block(MPADecodeContext *s, GranuleDef *g)

  1778. {

  1779.     int i, j, k, len;

  1780.     int32_t *ptr, *dst, *ptr1;

  1781.     int32_t tmp[576];

  1782. 

  1783.     if (g->block_type != 2)

  1784.         return;

  1785. 

  1786.     if (g->switch_point) {

  1787.         if (s->sample_rate_index != 8) {

  1788.             ptr = g->sb_hybrid + 36;

  1789.         } else {

  1790.             ptr = g->sb_hybrid + 48;

  1791.         }

  1792.     } else {

  1793.         ptr = g->sb_hybrid;

  1794.     }

  1795. 

  1796.     for(i=g->short_start;i<13;i++) {

  1797.         len = band_size_short[s->sample_rate_index][i];

  1798.         ptr1 = ptr;

  1799.         for(k=0;k<3;k++) {

  1800.             dst = tmp + k;

  1801.             for(j=len;j>0;j--) {

  1802.                 *dst = *ptr++;

  1803.                 dst += 3;

  1804.             }

  1805.         }

  1806.         memcpy(ptr1, tmp, len * 3 * sizeof(int32_t));

  1807.     }

  1808. }

  1809. 

  1810. #define ISQRT2 FIXR(0.70710678118654752440)

  1811. 

  1812. static void compute_stereo(MPADecodeContext *s,

  1813.                            GranuleDef *g0, GranuleDef *g1)

  1814. {

  1815.     int i, j, k, l;

  1816.     int32_t v1, v2;

  1817.     int sf_max, tmp0, tmp1, sf, len, non_zero_found;

  1818.     int32_t (*is_tab)[16];

  1819.     int32_t *tab0, *tab1;

  1820.     int non_zero_found_short[3];

  1821. 

  1822.     /* intensity stereo */

  1823.     if (s->mode_ext & MODE_EXT_I_STEREO) {

  1824.         if (!s->lsf) {

  1825.             is_tab = is_table;

  1826.             sf_max = 7;

  1827.         } else {

  1828.             is_tab = is_table_lsf[g1->scalefac_compress & 1];

  1829.             sf_max = 16;

  1830.         }

  1831. 

  1832.         tab0 = g0->sb_hybrid + 576;

  1833.         tab1 = g1->sb_hybrid + 576;

  1834. 

  1835.         non_zero_found_short[0] = 0;

  1836.         non_zero_found_short[1] = 0;

  1837.         non_zero_found_short[2] = 0;

  1838.         k = (13 - g1->short_start) * 3 + g1->long_end - 3;

  1839.         for(i = 12;i >= g1->short_start;i--) {

  1840.             /* for last band, use previous scale factor */

  1841.             if (i != 11)

  1842.                 k -= 3;

  1843.             len = band_size_short[s->sample_rate_index][i];

  1844.             for(l=2;l>=0;l--) {

  1845.                 tab0 -= len;

  1846.                 tab1 -= len;

  1847.                 if (!non_zero_found_short[l]) {

  1848.                     /* test if non zero band. if so, stop doing i-stereo */

  1849.                     for(j=0;j<len;j++) {

  1850.                         if (tab1[j] != 0) {

  1851.                             non_zero_found_short[l] = 1;

  1852.                             goto found1;

  1853.                         }

  1854.                     }

  1855.                     sf = g1->scale_factors[k + l];

  1856.                     if (sf >= sf_max)

  1857.                         goto found1;

  1858. 

  1859.                     v1 = is_tab[0][sf];

  1860.                     v2 = is_tab[1][sf];

  1861.                     for(j=0;j<len;j++) {

  1862.                         tmp0 = tab0[j];

  1863.                         tab0[j] = MULL(tmp0, v1);

  1864.                         tab1[j] = MULL(tmp0, v2);

  1865.                     }

  1866.                 } else {

  1867.                 found1:

  1868.                     if (s->mode_ext & MODE_EXT_MS_STEREO) {

  1869.                         /* lower part of the spectrum : do ms stereo

  1870.                            if enabled */

  1871.                         for(j=0;j<len;j++) {

  1872.                             tmp0 = tab0[j];

  1873.                             tmp1 = tab1[j];

  1874.                             tab0[j] = MULL(tmp0 + tmp1, ISQRT2);

  1875.                             tab1[j] = MULL(tmp0 - tmp1, ISQRT2);

  1876.                         }

  1877.                     }

  1878.                 }

  1879.             }

  1880.         }

  1881. 

  1882.         non_zero_found = non_zero_found_short[0] |

  1883.             non_zero_found_short[1] |

  1884.             non_zero_found_short[2];

  1885. 

  1886.         for(i = g1->long_end - 1;i >= 0;i--) {

  1887.             len = band_size_long[s->sample_rate_index][i];

  1888.             tab0 -= len;

  1889.             tab1 -= len;

  1890.             /* test if non zero band. if so, stop doing i-stereo */

  1891.             if (!non_zero_found) {

  1892.                 for(j=0;j<len;j++) {

  1893.                     if (tab1[j] != 0) {

  1894.                         non_zero_found = 1;

  1895.                         goto found2;

  1896.                     }

  1897.                 }

  1898.                 /* for last band, use previous scale factor */

  1899.                 k = (i == 21) ? 20 : i;

  1900.                 sf = g1->scale_factors[k];

  1901.                 if (sf >= sf_max)

  1902.                     goto found2;

  1903.                 v1 = is_tab[0][sf];

  1904.                 v2 = is_tab[1][sf];

  1905.                 for(j=0;j<len;j++) {

  1906.                     tmp0 = tab0[j];

  1907.                     tab0[j] = MULL(tmp0, v1);

  1908.                     tab1[j] = MULL(tmp0, v2);

  1909.                 }

  1910.             } else {

  1911.             found2:

  1912.                 if (s->mode_ext & MODE_EXT_MS_STEREO) {

  1913.                     /* lower part of the spectrum : do ms stereo

  1914.                        if enabled */

  1915.                     for(j=0;j<len;j++) {

  1916.                         tmp0 = tab0[j];

  1917.                         tmp1 = tab1[j];

  1918.                         tab0[j] = MULL(tmp0 + tmp1, ISQRT2);

  1919.                         tab1[j] = MULL(tmp0 - tmp1, ISQRT2);

  1920.                     }

  1921.                 }

  1922.             }

  1923.         }

  1924.     } else if (s->mode_ext & MODE_EXT_MS_STEREO) {

  1925.         /* ms stereo ONLY */

  1926.         /* NOTE: the 1/sqrt(2) normalization factor is included in the

  1927.            global gain */

  1928.         tab0 = g0->sb_hybrid;

  1929.         tab1 = g1->sb_hybrid;

  1930.         for(i=0;i<576;i++) {

  1931.             tmp0 = tab0[i];

  1932.             tmp1 = tab1[i];

  1933.             tab0[i] = tmp0 + tmp1;

  1934.             tab1[i] = tmp0 - tmp1;

  1935.         }

  1936.     }

  1937. }

  1938. 

  1939. static void compute_antialias_integer(MPADecodeContext *s,

  1940.                               GranuleDef *g)

  1941. {

  1942.     int32_t *ptr, *csa;

  1943.     int n, i;

  1944. 

  1945.     /* we antialias only "long" bands */

  1946.     if (g->block_type == 2) {

  1947.         if (!g->switch_point)

  1948.             return;

  1949.         /* XXX: check this for 8000Hz case */

  1950.         n = 1;

  1951.     } else {

  1952.         n = SBLIMIT - 1;

  1953.     }

  1954. 

  1955.     ptr = g->sb_hybrid + 18;

  1956.     for(i = n;i > 0;i--) {

  1957.         int tmp0, tmp1, tmp2;

  1958.         csa = &csa_table[0][0];

  1959. #define INT_AA(j) \

  1960.             tmp0 = ptr[-1-j];\

  1961.             tmp1 = ptr[   j];\

  1962.             tmp2= MULH(tmp0 + tmp1, csa[0+4*j]);\

  1963.             ptr[-1-j] = 4*(tmp2 - MULH(tmp1, csa[2+4*j]));\

  1964.             ptr[   j] = 4*(tmp2 + MULH(tmp0, csa[3+4*j]));

  1965. 

  1966.         INT_AA(0)

  1967.         INT_AA(1)

  1968.         INT_AA(2)

  1969.         INT_AA(3)

  1970.         INT_AA(4)

  1971.         INT_AA(5)

  1972.         INT_AA(6)

  1973.         INT_AA(7)

  1974. 

  1975.         ptr += 18;

  1976.     }

  1977. }

  1978. 

  1979. static void compute_antialias_float(MPADecodeContext *s,

  1980.                               GranuleDef *g)

  1981. {

  1982.     int32_t *ptr;

  1983.     int n, i;

  1984. 

  1985.     /* we antialias only "long" bands */

  1986.     if (g->block_type == 2) {

  1987.         if (!g->switch_point)

  1988.             return;

  1989.         /* XXX: check this for 8000Hz case */

  1990.         n = 1;

  1991.     } else {

  1992.         n = SBLIMIT - 1;

  1993.     }

  1994. 

  1995.     ptr = g->sb_hybrid + 18;

  1996.     for(i = n;i > 0;i--) {

  1997.         float tmp0, tmp1;

  1998.         float *csa = &csa_table_float[0][0];

  1999. #define FLOAT_AA(j)\

  2000.         tmp0= ptr[-1-j];\

  2001.         tmp1= ptr[   j];\

  2002.         ptr[-1-j] = lrintf(tmp0 * csa[0+4*j] - tmp1 * csa[1+4*j]);\

  2003.         ptr[   j] = lrintf(tmp0 * csa[1+4*j] + tmp1 * csa[0+4*j]);

  2004. 

  2005.         FLOAT_AA(0)

  2006.         FLOAT_AA(1)

  2007.         FLOAT_AA(2)

  2008.         FLOAT_AA(3)

  2009.         FLOAT_AA(4)

  2010.         FLOAT_AA(5)

  2011.         FLOAT_AA(6)

  2012.         FLOAT_AA(7)

  2013. 

  2014.         ptr += 18;

  2015.     }

  2016. }

  2017. 

  2018. static void compute_imdct(MPADecodeContext *s,

  2019.                           GranuleDef *g,

  2020.                           int32_t *sb_samples,

  2021.                           int32_t *mdct_buf)

  2022. {

  2023.     int32_t *ptr, *win, *win1, *buf, *out_ptr, *ptr1;

  2024.     int32_t out2[12];

  2025.     int i, j, mdct_long_end, v, sblimit;

  2026. 

  2027.     /* find last non zero block */

  2028.     ptr = g->sb_hybrid + 576;

  2029.     ptr1 = g->sb_hybrid + 2 * 18;

  2030.     while (ptr >= ptr1) {

  2031.         ptr -= 6;

  2032.         v = ptr[0] | ptr[1] | ptr[2] | ptr[3] | ptr[4] | ptr[5];

  2033.         if (v != 0)

  2034.             break;

  2035.     }

  2036.     sblimit = ((ptr - g->sb_hybrid) / 18) + 1;

  2037. 

  2038.     if (g->block_type == 2) {

  2039.         /* XXX: check for 8000 Hz */

  2040.         if (g->switch_point)

  2041.             mdct_long_end = 2;

  2042.         else

  2043.             mdct_long_end = 0;

  2044.     } else {

  2045.         mdct_long_end = sblimit;

  2046.     }

  2047. 

  2048.     buf = mdct_buf;

  2049.     ptr = g->sb_hybrid;

  2050.     for(j=0;j<mdct_long_end;j++) {

  2051.         /* apply window & overlap with previous buffer */

  2052.         out_ptr = sb_samples + j;

  2053.         /* select window */

  2054.         if (g->switch_point && j < 2)

  2055.             win1 = mdct_win[0];

  2056.         else

  2057.             win1 = mdct_win[g->block_type];

  2058.         /* select frequency inversion */

  2059.         win = win1 + ((4 * 36) & -(j & 1));

  2060.         imdct36(out_ptr, buf, ptr, win);

  2061.         out_ptr += 18*SBLIMIT;

  2062.         ptr += 18;

  2063.         buf += 18;

  2064.     }

  2065.     for(j=mdct_long_end;j<sblimit;j++) {

  2066.         /* select frequency inversion */

  2067.         win = mdct_win[2] + ((4 * 36) & -(j & 1));

  2068.         out_ptr = sb_samples + j;

  2069. 

  2070.         for(i=0; i<6; i++){

  2071.             *out_ptr = buf[i];

  2072.             out_ptr += SBLIMIT;

  2073.         }

  2074.         imdct12(out2, ptr + 0);

  2075.         for(i=0;i<6;i++) {

  2076.             *out_ptr = MULH(out2[i], win[i]) + buf[i + 6*1];

  2077.             buf[i + 6*2] = MULH(out2[i + 6], win[i + 6]);

  2078.             out_ptr += SBLIMIT;

  2079.         }

  2080.         imdct12(out2, ptr + 1);

  2081.         for(i=0;i<6;i++) {

  2082.             *out_ptr = MULH(out2[i], win[i]) + buf[i + 6*2];

  2083.             buf[i + 6*0] = MULH(out2[i + 6], win[i + 6]);

  2084.             out_ptr += SBLIMIT;

  2085.         }

  2086.         imdct12(out2, ptr + 2);

  2087.         for(i=0;i<6;i++) {

  2088.             buf[i + 6*0] = MULH(out2[i], win[i]) + buf[i + 6*0];

  2089.             buf[i + 6*1] = MULH(out2[i + 6], win[i + 6]);

  2090.             buf[i + 6*2] = 0;

  2091.         }

  2092.         ptr += 18;

  2093.         buf += 18;

  2094.     }

  2095.     /* zero bands */

  2096.     for(j=sblimit;j<SBLIMIT;j++) {

  2097.         /* overlap */

  2098.         out_ptr = sb_samples + j;

  2099.         for(i=0;i<18;i++) {

  2100.             *out_ptr = buf[i];

  2101.             buf[i] = 0;

  2102.             out_ptr += SBLIMIT;

  2103.         }

  2104.         buf += 18;

  2105.     }

  2106. }

  2107. 

  2108. #if defined(DEBUG)

  2109. void sample_dump(int fnum, int32_t *tab, int n)

  2110. {

  2111.     static FILE *files[16], *f;

  2112.     char buf[512];

  2113.     int i;

  2114.     int32_t v;

  2115. 

  2116.     f = files[fnum];

  2117.     if (!f) {

  2118.         snprintf(buf, sizeof(buf), "/tmp/out%d.%s.pcm",

  2119.                 fnum,

  2120. #ifdef USE_HIGHPRECISION

  2121.                 "hp"

  2122. #else

  2123.                 "lp"

  2124. #endif

  2125.                 );

  2126.         f = fopen(buf, "w");

  2127.         if (!f)

  2128.             return;

  2129.         files[fnum] = f;

  2130.     }

  2131. 

  2132.     if (fnum == 0) {

  2133.         static int pos = 0;

  2134.         av_log(NULL, AV_LOG_DEBUG, "pos=%d\n", pos);

  2135.         for(i=0;i<n;i++) {

  2136.             av_log(NULL, AV_LOG_DEBUG, " %0.4f", (double)tab[i] / FRAC_ONE);

  2137.             if ((i % 18) == 17)

  2138.                 av_log(NULL, AV_LOG_DEBUG, "\n");

  2139.         }

  2140.         pos += n;

  2141.     }

  2142.     for(i=0;i<n;i++) {

  2143.         /* normalize to 23 frac bits */

  2144.         v = tab[i] << (23 - FRAC_BITS);

  2145.         fwrite(&v, 1, sizeof(int32_t), f);

  2146.     }

  2147. }

  2148. #endif

  2149. 

  2150. 

  2151. /* main layer3 decoding function */

  2152. static int mp_decode_layer3(MPADecodeContext *s)

  2153. {

  2154.     int nb_granules, main_data_begin, private_bits;

  2155.     int gr, ch, blocksplit_flag, i, j, k, n, bits_pos, bits_left;

  2156.     GranuleDef granules[2][2], *g;

  2157.     int16_t exponents[576];

  2158. 

  2159.     /* read side info */

  2160.     if (s->lsf) {

  2161.         main_data_begin = get_bits(&s->gb, 8);

  2162.         if (s->nb_channels == 2)

  2163.             private_bits = get_bits(&s->gb, 2);

  2164.         else

  2165.             private_bits = get_bits(&s->gb, 1);

  2166.         nb_granules = 1;

  2167.     } else {

  2168.         main_data_begin = get_bits(&s->gb, 9);

  2169.         if (s->nb_channels == 2)

  2170.             private_bits = get_bits(&s->gb, 3);

  2171.         else

  2172.             private_bits = get_bits(&s->gb, 5);

  2173.         nb_granules = 2;

  2174.         for(ch=0;ch<s->nb_channels;ch++) {

  2175.             granules[ch][0].scfsi = 0; /* all scale factors are transmitted */

  2176.             granules[ch][1].scfsi = get_bits(&s->gb, 4);

  2177.         }

  2178.     }

  2179. 

  2180.     for(gr=0;gr<nb_granules;gr++) {

  2181.         for(ch=0;ch<s->nb_channels;ch++) {

  2182.             dprintf("gr=%d ch=%d: side_info\n", gr, ch);

  2183.             g = &granules[ch][gr];

  2184.             g->part2_3_length = get_bits(&s->gb, 12);

  2185.             g->big_values = get_bits(&s->gb, 9);

  2186.             g->global_gain = get_bits(&s->gb, 8);

  2187.             /* if MS stereo only is selected, we precompute the

  2188.                1/sqrt(2) renormalization factor */

  2189.             if ((s->mode_ext & (MODE_EXT_MS_STEREO | MODE_EXT_I_STEREO)) ==

  2190.                 MODE_EXT_MS_STEREO)

  2191.                 g->global_gain -= 2;

  2192.             if (s->lsf)

  2193.                 g->scalefac_compress = get_bits(&s->gb, 9);

  2194.             else

  2195.                 g->scalefac_compress = get_bits(&s->gb, 4);

  2196.             blocksplit_flag = get_bits(&s->gb, 1);

  2197.             if (blocksplit_flag) {

  2198.                 g->block_type = get_bits(&s->gb, 2);

  2199.                 if (g->block_type == 0)

  2200.                     return -1;

  2201.                 g->switch_point = get_bits(&s->gb, 1);

  2202.                 for(i=0;i<2;i++)

  2203.                     g->table_select[i] = get_bits(&s->gb, 5);

  2204.                 for(i=0;i<3;i++)

  2205.                     g->subblock_gain[i] = get_bits(&s->gb, 3);

  2206.                 /* compute huffman coded region sizes */

  2207.                 if (g->block_type == 2)

  2208.                     g->region_size[0] = (36 / 2);

  2209.                 else {

  2210.                     if (s->sample_rate_index <= 2)

  2211.                         g->region_size[0] = (36 / 2);

  2212.                     else if (s->sample_rate_index != 8)

  2213.                         g->region_size[0] = (54 / 2);

  2214.                     else

  2215.                         g->region_size[0] = (108 / 2);

  2216.                 }

  2217.                 g->region_size[1] = (576 / 2);

  2218.             } else {

  2219.                 int region_address1, region_address2, l;

  2220.                 g->block_type = 0;

  2221.                 g->switch_point = 0;

  2222.                 for(i=0;i<3;i++)

  2223.                     g->table_select[i] = get_bits(&s->gb, 5);

  2224.                 /* compute huffman coded region sizes */

  2225.                 region_address1 = get_bits(&s->gb, 4);

  2226.                 region_address2 = get_bits(&s->gb, 3);

  2227.                 dprintf("region1=%d region2=%d\n",

  2228.                         region_address1, region_address2);

  2229.                 g->region_size[0] =

  2230.                     band_index_long[s->sample_rate_index][region_address1 + 1] >> 1;

  2231.                 l = region_address1 + region_address2 + 2;

  2232.                 /* should not overflow */

  2233.                 if (l > 22)

  2234.                     l = 22;

  2235.                 g->region_size[1] =

  2236.                     band_index_long[s->sample_rate_index][l] >> 1;

  2237.             }

  2238.             /* convert region offsets to region sizes and truncate

  2239.                size to big_values */

  2240.             g->region_size[2] = (576 / 2);

  2241.             j = 0;

  2242.             for(i=0;i<3;i++) {

  2243.                 k = FFMIN(g->region_size[i], g->big_values);

  2244.                 g->region_size[i] = k - j;

  2245.                 j = k;

  2246.             }

  2247. 

  2248.             /* compute band indexes */

  2249.             if (g->block_type == 2) {

  2250.                 if (g->switch_point) {

  2251.                     /* if switched mode, we handle the 36 first samples as

  2252.                        long blocks.  For 8000Hz, we handle the 48 first

  2253.                        exponents as long blocks (XXX: check this!) */

  2254.                     if (s->sample_rate_index <= 2)

  2255.                         g->long_end = 8;

  2256.                     else if (s->sample_rate_index != 8)

  2257.                         g->long_end = 6;

  2258.                     else

  2259.                         g->long_end = 4; /* 8000 Hz */

  2260. 

  2261.                     g->short_start = 2 + (s->sample_rate_index != 8);

  2262.                 } else {

  2263.                     g->long_end = 0;

  2264.                     g->short_start = 0;

  2265.                 }

  2266.             } else {

  2267.                 g->short_start = 13;

  2268.                 g->long_end = 22;

  2269.             }

  2270. 

  2271.             g->preflag = 0;

  2272.             if (!s->lsf)

  2273.                 g->preflag = get_bits(&s->gb, 1);

  2274.             g->scalefac_scale = get_bits(&s->gb, 1);

  2275.             g->count1table_select = get_bits(&s->gb, 1);

  2276.             dprintf("block_type=%d switch_point=%d\n",

  2277.                     g->block_type, g->switch_point);

  2278.         }

  2279.     }

  2280. 

  2281.   if (!s->adu_mode) {

  2282.     /* now we get bits from the main_data_begin offset */

  2283.     dprintf("seekback: %d\n", main_data_begin);

  2284.     seek_to_maindata(s, main_data_begin);

  2285.   }

  2286. 

  2287.     for(gr=0;gr<nb_granules;gr++) {

  2288.         for(ch=0;ch<s->nb_channels;ch++) {

  2289.             g = &granules[ch][gr];

  2290. 

  2291.             bits_pos = get_bits_count(&s->gb);

  2292. 

  2293.             if (!s->lsf) {

  2294.                 uint8_t *sc;

  2295.                 int slen, slen1, slen2;

  2296. 

  2297.                 /* MPEG1 scale factors */

  2298.                 slen1 = slen_table[0][g->scalefac_compress];

  2299.                 slen2 = slen_table[1][g->scalefac_compress];

  2300.                 dprintf("slen1=%d slen2=%d\n", slen1, slen2);

  2301.                 if (g->block_type == 2) {

  2302.                     n = g->switch_point ? 17 : 18;

  2303.                     j = 0;

  2304.                     for(i=0;i<n;i++)

  2305.                         g->scale_factors[j++] = get_bitsz(&s->gb, slen1);

  2306.                     for(i=0;i<18;i++)

  2307.                         g->scale_factors[j++] = get_bitsz(&s->gb, slen2);

  2308.                     for(i=0;i<3;i++)

  2309.                         g->scale_factors[j++] = 0;

  2310.                 } else {

  2311.                     sc = granules[ch][0].scale_factors;

  2312.                     j = 0;

  2313.                     for(k=0;k<4;k++) {

  2314.                         n = (k == 0 ? 6 : 5);

  2315.                         if ((g->scfsi & (0x8 >> k)) == 0) {

  2316.                             slen = (k < 2) ? slen1 : slen2;

  2317.                             for(i=0;i<n;i++)

  2318.                                 g->scale_factors[j++] = get_bitsz(&s->gb, slen);

  2319.                         } else {

  2320.                             /* simply copy from last granule */

  2321.                             for(i=0;i<n;i++) {

  2322.                                 g->scale_factors[j] = sc[j];

  2323.                                 j++;

  2324.                             }

  2325.                         }

  2326.                     }

  2327.                     g->scale_factors[j++] = 0;

  2328.                 }

  2329. #if defined(DEBUG)

  2330.                 {

  2331.                     dprintf("scfsi=%x gr=%d ch=%d scale_factors:\n",

  2332.                            g->scfsi, gr, ch);

  2333.                     for(i=0;i<j;i++)

  2334.                         dprintf(" %d", g->scale_factors[i]);

  2335.                     dprintf("\n");

  2336.                 }

  2337. #endif

  2338.             } else {

  2339.                 int tindex, tindex2, slen[4], sl, sf;

  2340. 

  2341.                 /* LSF scale factors */

  2342.                 if (g->block_type == 2) {

  2343.                     tindex = g->switch_point ? 2 : 1;

  2344.                 } else {

  2345.                     tindex = 0;

  2346.                 }

  2347.                 sf = g->scalefac_compress;

  2348.                 if ((s->mode_ext & MODE_EXT_I_STEREO) && ch == 1) {

  2349.                     /* intensity stereo case */

  2350.                     sf >>= 1;

  2351.                     if (sf < 180) {

  2352.                         lsf_sf_expand(slen, sf, 6, 6, 0);

  2353.                         tindex2 = 3;

  2354.                     } else if (sf < 244) {

  2355.                         lsf_sf_expand(slen, sf - 180, 4, 4, 0);

  2356.                         tindex2 = 4;

  2357.                     } else {

  2358.                         lsf_sf_expand(slen, sf - 244, 3, 0, 0);

  2359.                         tindex2 = 5;

  2360.                     }

  2361.                 } else {

  2362.                     /* normal case */

  2363.                     if (sf < 400) {

  2364.                         lsf_sf_expand(slen, sf, 5, 4, 4);

  2365.                         tindex2 = 0;

  2366.                     } else if (sf < 500) {

  2367.                         lsf_sf_expand(slen, sf - 400, 5, 4, 0);

  2368.                         tindex2 = 1;

  2369.                     } else {

  2370.                         lsf_sf_expand(slen, sf - 500, 3, 0, 0);

  2371.                         tindex2 = 2;

  2372.                         g->preflag = 1;

  2373.                     }

  2374.                 }

  2375. 

  2376.                 j = 0;

  2377.                 for(k=0;k<4;k++) {

  2378.                     n = lsf_nsf_table[tindex2][tindex][k];

  2379.                     sl = slen[k];

  2380.                     for(i=0;i<n;i++)

  2381.                         g->scale_factors[j++] = get_bitsz(&s->gb, sl);

  2382.                 }

  2383.                 /* XXX: should compute exact size */

  2384.                 for(;j<40;j++)

  2385.                     g->scale_factors[j] = 0;

  2386. #if defined(DEBUG)

  2387.                 {

  2388.                     dprintf("gr=%d ch=%d scale_factors:\n",

  2389.                            gr, ch);

  2390.                     for(i=0;i<40;i++)

  2391.                         dprintf(" %d", g->scale_factors[i]);

  2392.                     dprintf("\n");

  2393.                 }

  2394. #endif

  2395.             }

  2396. 

  2397.             exponents_from_scale_factors(s, g, exponents);

  2398. 

  2399.             /* read Huffman coded residue */

  2400.             if (huffman_decode(s, g, exponents,

  2401.                                bits_pos + g->part2_3_length) < 0)

  2402.                 return -1;

  2403. #if defined(DEBUG)

  2404.             sample_dump(0, g->sb_hybrid, 576);

  2405. #endif

  2406. 

  2407.             /* skip extension bits */

  2408.             bits_left = g->part2_3_length - (get_bits_count(&s->gb) - bits_pos);

  2409.             if (bits_left < 0) {

  2410.                 dprintf("bits_left=%d\n", bits_left);

  2411.                 return -1;

  2412.             }

  2413.             while (bits_left >= 16) {

  2414.                 skip_bits(&s->gb, 16);

  2415.                 bits_left -= 16;

  2416.             }

  2417.             if (bits_left > 0)

  2418.                 skip_bits(&s->gb, bits_left);

  2419.         } /* ch */

  2420. 

  2421.         if (s->nb_channels == 2)

  2422.             compute_stereo(s, &granules[0][gr], &granules[1][gr]);

  2423. 

  2424.         for(ch=0;ch<s->nb_channels;ch++) {

  2425.             g = &granules[ch][gr];

  2426. 

  2427.             reorder_block(s, g);

  2428. #if defined(DEBUG)

  2429.             sample_dump(0, g->sb_hybrid, 576);

  2430. #endif

  2431.             s->compute_antialias(s, g);

  2432. #if defined(DEBUG)

  2433.             sample_dump(1, g->sb_hybrid, 576);

  2434. #endif

  2435.             compute_imdct(s, g, &s->sb_samples[ch][18 * gr][0], s->mdct_buf[ch]);

  2436. #if defined(DEBUG)

  2437.             sample_dump(2, &s->sb_samples[ch][18 * gr][0], 576);

  2438. #endif

  2439.         }

  2440.     } /* gr */

  2441.     return nb_granules * 18;

  2442. }

  2443. 

  2444. static int mp_decode_frame(MPADecodeContext *s,

  2445.                            OUT_INT *samples)

  2446. {

  2447.     int i, nb_frames, ch;

  2448.     OUT_INT *samples_ptr;

  2449. 

  2450.     init_get_bits(&s->gb, s->inbuf + HEADER_SIZE,

  2451.                   (s->inbuf_ptr - s->inbuf - HEADER_SIZE)*8);

  2452. 

  2453.     /* skip error protection field */

  2454.     if (s->error_protection)

  2455.         get_bits(&s->gb, 16);

  2456. 

  2457.     dprintf("frame %d:\n", s->frame_count);

  2458.     switch(s->layer) {

  2459.     case 1:

  2460.         nb_frames = mp_decode_layer1(s);

  2461.         break;

  2462.     case 2:

  2463.         nb_frames = mp_decode_layer2(s);

  2464.         break;

  2465.     case 3:

  2466.     default:

  2467.         nb_frames = mp_decode_layer3(s);

  2468.         break;

  2469.     }

  2470. #if defined(DEBUG)

  2471.     for(i=0;i<nb_frames;i++) {

  2472.         for(ch=0;ch<s->nb_channels;ch++) {

  2473.             int j;

  2474.             dprintf("%d-%d:", i, ch);

  2475.             for(j=0;j<SBLIMIT;j++)

  2476.                 dprintf(" %0.6f", (double)s->sb_samples[ch][i][j] / FRAC_ONE);

  2477.             dprintf("\n");

  2478.         }

  2479.     }

  2480. #endif

  2481.     /* apply the synthesis filter */

  2482.     for(ch=0;ch<s->nb_channels;ch++) {

  2483.         samples_ptr = samples + ch;

  2484.         for(i=0;i<nb_frames;i++) {

  2485.             ff_mpa_synth_filter(s->synth_buf[ch], &(s->synth_buf_offset[ch]),

  2486.                          window, &s->dither_state,

  2487.                          samples_ptr, s->nb_channels,

  2488.                          s->sb_samples[ch][i]);

  2489.             samples_ptr += 32 * s->nb_channels;

  2490.         }

  2491.     }

  2492. #ifdef DEBUG

  2493.     s->frame_count++;

  2494. #endif

  2495.     return nb_frames * 32 * sizeof(OUT_INT) * s->nb_channels;

  2496. }

  2497. 

  2498. static int decode_frame(AVCodecContext * avctx,

  2499.                         void *data, int *data_size,

  2500.                         uint8_t * buf, int buf_size)

  2501. {

  2502.     MPADecodeContext *s = avctx->priv_data;

  2503.     uint32_t header;

  2504.     uint8_t *buf_ptr;

  2505.     int len, out_size;

  2506.     OUT_INT *out_samples = data;

  2507. 

  2508.     buf_ptr = buf;

  2509.     while (buf_size > 0) {

  2510.         len = s->inbuf_ptr - s->inbuf;

  2511.         if (s->frame_size == 0) {

  2512.             /* special case for next header for first frame in free

  2513.                format case (XXX: find a simpler method) */

  2514.             if (s->free_format_next_header != 0) {

  2515.                 s->inbuf[0] = s->free_format_next_header >> 24;

  2516.                 s->inbuf[1] = s->free_format_next_header >> 16;

  2517.                 s->inbuf[2] = s->free_format_next_header >> 8;

  2518.                 s->inbuf[3] = s->free_format_next_header;

  2519.                 s->inbuf_ptr = s->inbuf + 4;

  2520.                 s->free_format_next_header = 0;

  2521.                 goto got_header;

  2522.             }

  2523.             /* no header seen : find one. We need at least HEADER_SIZE

  2524.                bytes to parse it */

  2525.             len = HEADER_SIZE - len;

  2526.             if (len > buf_size)

  2527.                 len = buf_size;

  2528.             if (len > 0) {

  2529.                 memcpy(s->inbuf_ptr, buf_ptr, len);

  2530.                 buf_ptr += len;

  2531.                 buf_size -= len;

  2532.                 s->inbuf_ptr += len;

  2533.             }

  2534.             if ((s->inbuf_ptr - s->inbuf) >= HEADER_SIZE) {

  2535.             got_header:

  2536.                 header = (s->inbuf[0] << 24) | (s->inbuf[1] << 16) |

  2537.                     (s->inbuf[2] << 8) | s->inbuf[3];

  2538. 

  2539.                 if (ff_mpa_check_header(header) < 0) {

  2540.                     /* no sync found : move by one byte (inefficient, but simple!) */

  2541.                     memmove(s->inbuf, s->inbuf + 1, s->inbuf_ptr - s->inbuf - 1);

  2542.                     s->inbuf_ptr--;

  2543.                     dprintf("skip %x\n", header);

  2544.                     /* reset free format frame size to give a chance

  2545.                        to get a new bitrate */

  2546.                     s->free_format_frame_size = 0;

  2547.                 } else {

  2548.                     if (decode_header(s, header) == 1) {

  2549.                         /* free format: prepare to compute frame size */

  2550.                         s->frame_size = -1;

  2551.                     }

  2552.                     /* update codec info */

  2553.                     avctx->sample_rate = s->sample_rate;

  2554.                     avctx->channels = s->nb_channels;

  2555.                     avctx->bit_rate = s->bit_rate;

  2556.                     avctx->sub_id = s->layer;

  2557.                     switch(s->layer) {

  2558.                     case 1:

  2559.                         avctx->frame_size = 384;

  2560.                         break;

  2561.                     case 2:

  2562.                         avctx->frame_size = 1152;

  2563.                         break;

  2564.                     case 3:

  2565.                         if (s->lsf)

  2566.                             avctx->frame_size = 576;

  2567.                         else

  2568.                             avctx->frame_size = 1152;

  2569.                         break;

  2570.                     }

  2571.                 }

  2572.             }

  2573.         } else if (s->frame_size == -1) {

  2574.             /* free format : find next sync to compute frame size */

  2575.             len = MPA_MAX_CODED_FRAME_SIZE - len;

  2576.             if (len > buf_size)

  2577.                 len = buf_size;

  2578.             if (len == 0) {

  2579.                 /* frame too long: resync */

  2580.                 s->frame_size = 0;

  2581.                 memmove(s->inbuf, s->inbuf + 1, s->inbuf_ptr - s->inbuf - 1);

  2582.                 s->inbuf_ptr--;

  2583.             } else {

  2584.                 uint8_t *p, *pend;

  2585.                 uint32_t header1;

  2586.                 int padding;

  2587. 

  2588.                 memcpy(s->inbuf_ptr, buf_ptr, len);

  2589.                 /* check for header */

  2590.                 p = s->inbuf_ptr - 3;

  2591.                 pend = s->inbuf_ptr + len - 4;

  2592.                 while (p <= pend) {

  2593.                     header = (p[0] << 24) | (p[1] << 16) |

  2594.                         (p[2] << 8) | p[3];

  2595.                     header1 = (s->inbuf[0] << 24) | (s->inbuf[1] << 16) |

  2596.                         (s->inbuf[2] << 8) | s->inbuf[3];

  2597.                     /* check with high probability that we have a

  2598.                        valid header */

  2599.                     if ((header & SAME_HEADER_MASK) ==

  2600.                         (header1 & SAME_HEADER_MASK)) {

  2601.                         /* header found: update pointers */

  2602.                         len = (p + 4) - s->inbuf_ptr;

  2603.                         buf_ptr += len;

  2604.                         buf_size -= len;

  2605.                         s->inbuf_ptr = p;

  2606.                         /* compute frame size */

  2607.                         s->free_format_next_header = header;

  2608.                         s->free_format_frame_size = s->inbuf_ptr - s->inbuf;

  2609.                         padding = (header1 >> 9) & 1;

  2610.                         if (s->layer == 1)

  2611.                             s->free_format_frame_size -= padding * 4;

  2612.                         else

  2613.                             s->free_format_frame_size -= padding;

  2614.                         dprintf("free frame size=%d padding=%d\n",

  2615.                                 s->free_format_frame_size, padding);

  2616.                         decode_header(s, header1);

  2617.                         goto next_data;

  2618.                     }

  2619.                     p++;

  2620.                 }

  2621.                 /* not found: simply increase pointers */

  2622.                 buf_ptr += len;

  2623.                 s->inbuf_ptr += len;

  2624.                 buf_size -= len;

  2625.             }

  2626.         } else if (len < s->frame_size) {

  2627.             if (s->frame_size > MPA_MAX_CODED_FRAME_SIZE)

  2628.                 s->frame_size = MPA_MAX_CODED_FRAME_SIZE;

  2629.             len = s->frame_size - len;

  2630.             if (len > buf_size)

  2631.                 len = buf_size;

  2632.             memcpy(s->inbuf_ptr, buf_ptr, len);

  2633.             buf_ptr += len;

  2634.             s->inbuf_ptr += len;

  2635.             buf_size -= len;

  2636.         }

  2637.     next_data:

  2638.         if (s->frame_size > 0 &&

  2639.             (s->inbuf_ptr - s->inbuf) >= s->frame_size) {

  2640.             if (avctx->parse_only) {

  2641.                 /* simply return the frame data */

  2642.                 *(uint8_t **)data = s->inbuf;

  2643.                 out_size = s->inbuf_ptr - s->inbuf;

  2644.             } else {

  2645.                 out_size = mp_decode_frame(s, out_samples);

  2646.             }

  2647.             s->inbuf_ptr = s->inbuf;

  2648.             s->frame_size = 0;

  2649.             if(out_size>=0)

  2650.                 *data_size = out_size;

  2651.             else

  2652.                 av_log(avctx, AV_LOG_DEBUG, "Error while decoding mpeg audio frame\n"); //FIXME return -1 / but also return the number of bytes consumed

  2653.             break;

  2654.         }

  2655.     }

  2656.     return buf_ptr - buf;

  2657. }

  2658. 

  2659. 

  2660. static int decode_frame_adu(AVCodecContext * avctx,

  2661.                         void *data, int *data_size,

  2662.                         uint8_t * buf, int buf_size)

  2663. {

  2664.     MPADecodeContext *s = avctx->priv_data;

  2665.     uint32_t header;

  2666.     int len, out_size;

  2667.     OUT_INT *out_samples = data;

  2668. 

  2669.     len = buf_size;

  2670. 

  2671.     // Discard too short frames

  2672.     if (buf_size < HEADER_SIZE) {

  2673.         *data_size = 0;

  2674.         return buf_size;

  2675.     }

  2676. 

  2677. 

  2678.     if (len > MPA_MAX_CODED_FRAME_SIZE)

  2679.         len = MPA_MAX_CODED_FRAME_SIZE;

  2680. 

  2681.     memcpy(s->inbuf, buf, len);

  2682.     s->inbuf_ptr = s->inbuf + len;

  2683. 

  2684.     // Get header and restore sync word

  2685.     header = (s->inbuf[0] << 24) | (s->inbuf[1] << 16) |

  2686.               (s->inbuf[2] << 8) | s->inbuf[3] | 0xffe00000;

  2687. 

  2688.     if (ff_mpa_check_header(header) < 0) { // Bad header, discard frame

  2689.         *data_size = 0;

  2690.         return buf_size;

  2691.     }

  2692. 

  2693.     decode_header(s, header);

  2694.     /* update codec info */

  2695.     avctx->sample_rate = s->sample_rate;

  2696.     avctx->channels = s->nb_channels;

  2697.     avctx->bit_rate = s->bit_rate;

  2698.     avctx->sub_id = s->layer;

  2699. 

  2700.     avctx->frame_size=s->frame_size = len;

  2701. 

  2702.     if (avctx->parse_only) {

  2703.         /* simply return the frame data */

  2704.         *(uint8_t **)data = s->inbuf;

  2705.         out_size = s->inbuf_ptr - s->inbuf;

  2706.     } else {

  2707.         out_size = mp_decode_frame(s, out_samples);

  2708.     }

  2709. 

  2710.     *data_size = out_size;

  2711.     return buf_size;

  2712. }

  2713. 

  2714. 

  2715. /* Next 3 arrays are indexed by channel config number (passed via codecdata) */

  2716. static int mp3Frames[16] = {0,1,1,2,3,3,4,5,2};   /* number of mp3 decoder instances */

  2717. static int mp3Channels[16] = {0,1,2,3,4,5,6,8,4}; /* total output channels */

  2718. /* offsets into output buffer, assume output order is FL FR BL BR C LFE */

  2719. static int chan_offset[9][5] = {

  2720.     {0},

  2721.     {0},            // C

  2722.     {0},            // FLR

  2723.     {2,0},          // C FLR

  2724.     {2,0,3},        // C FLR BS

  2725.     {4,0,2},        // C FLR BLRS

  2726.     {4,0,2,5},      // C FLR BLRS LFE

  2727.     {4,0,2,6,5},    // C FLR BLRS BLR LFE

  2728.     {0,2}           // FLR BLRS

  2729. };

  2730. 

  2731. 

  2732. static int decode_init_mp3on4(AVCodecContext * avctx)

  2733. {

  2734.     MP3On4DecodeContext *s = avctx->priv_data;

  2735.     int i;

  2736. 

  2737.     if ((avctx->extradata_size < 2) || (avctx->extradata == NULL)) {

  2738.         av_log(avctx, AV_LOG_ERROR, "Codec extradata missing or too short.\n");

  2739.         return -1;

  2740.     }

  2741. 

  2742.     s->chan_cfg = (((unsigned char *)avctx->extradata)[1] >> 3) & 0x0f;

  2743.     s->frames = mp3Frames[s->chan_cfg];

  2744.     if(!s->frames) {

  2745.         av_log(avctx, AV_LOG_ERROR, "Invalid channel config number.\n");

  2746.         return -1;

  2747.     }

  2748.     avctx->channels = mp3Channels[s->chan_cfg];

  2749. 

  2750.     /* Init the first mp3 decoder in standard way, so that all tables get builded

  2751.      * We replace avctx->priv_data with the context of the first decoder so that

  2752.      * decode_init() does not have to be changed.

  2753.      * Other decoders will be inited here copying data from the first context

  2754.      */

  2755.     // Allocate zeroed memory for the first decoder context

  2756.     s->mp3decctx[0] = av_mallocz(sizeof(MPADecodeContext));

  2757.     // Put decoder context in place to make init_decode() happy

  2758.     avctx->priv_data = s->mp3decctx[0];

  2759.     decode_init(avctx);

  2760.     // Restore mp3on4 context pointer

  2761.     avctx->priv_data = s;

  2762.     s->mp3decctx[0]->adu_mode = 1; // Set adu mode

  2763. 

  2764.     /* Create a separate codec/context for each frame (first is already ok).

  2765.      * Each frame is 1 or 2 channels - up to 5 frames allowed

  2766.      */

  2767.     for (i = 1; i < s->frames; i++) {

  2768.         s->mp3decctx[i] = av_mallocz(sizeof(MPADecodeContext));

  2769.         s->mp3decctx[i]->compute_antialias = s->mp3decctx[0]->compute_antialias;

  2770.         s->mp3decctx[i]->inbuf = &s->mp3decctx[i]->inbuf1[0][BACKSTEP_SIZE];

  2771.         s->mp3decctx[i]->inbuf_ptr = s->mp3decctx[i]->inbuf;

  2772.         s->mp3decctx[i]->adu_mode = 1;

  2773.     }

  2774. 

  2775.     return 0;

  2776. }

  2777. 

  2778. 

  2779. static int decode_close_mp3on4(AVCodecContext * avctx)

  2780. {

  2781.     MP3On4DecodeContext *s = avctx->priv_data;

  2782.     int i;

  2783. 

  2784.     for (i = 0; i < s->frames; i++)

  2785.         if (s->mp3decctx[i])

  2786.             av_free(s->mp3decctx[i]);

  2787. 

  2788.     return 0;

  2789. }

  2790. 

  2791. 

  2792. static int decode_frame_mp3on4(AVCodecContext * avctx,

  2793.                         void *data, int *data_size,

  2794.                         uint8_t * buf, int buf_size)

  2795. {

  2796.     MP3On4DecodeContext *s = avctx->priv_data;

  2797.     MPADecodeContext *m;

  2798.     int len, out_size = 0;

  2799.     uint32_t header;

  2800.     OUT_INT *out_samples = data;

  2801.     OUT_INT decoded_buf[MPA_FRAME_SIZE * MPA_MAX_CHANNELS];

  2802.     OUT_INT *outptr, *bp;

  2803.     int fsize;

  2804.     unsigned char *start2 = buf, *start;

  2805.     int fr, i, j, n;

  2806.     int off = avctx->channels;

  2807.     int *coff = chan_offset[s->chan_cfg];

  2808. 

  2809.     len = buf_size;

  2810. 

  2811.     // Discard too short frames

  2812.     if (buf_size < HEADER_SIZE) {

  2813.         *data_size = 0;

  2814.         return buf_size;

  2815.     }

  2816. 

  2817.     // If only one decoder interleave is not needed

  2818.     outptr = s->frames == 1 ? out_samples : decoded_buf;

  2819. 

  2820.     for (fr = 0; fr < s->frames; fr++) {

  2821.         start = start2;

  2822.         fsize = (start[0] << 4) | (start[1] >> 4);

  2823.         start2 += fsize;

  2824.         if (fsize > len)

  2825.             fsize = len;

  2826.         len -= fsize;

  2827.         if (fsize > MPA_MAX_CODED_FRAME_SIZE)

  2828.             fsize = MPA_MAX_CODED_FRAME_SIZE;

  2829.         m = s->mp3decctx[fr];

  2830.         assert (m != NULL);

  2831.         /* copy original to new */

  2832.         m->inbuf_ptr = m->inbuf + fsize;

  2833.         memcpy(m->inbuf, start, fsize);

  2834. 

  2835.         // Get header

  2836.         header = (m->inbuf[0] << 24) | (m->inbuf[1] << 16) |

  2837.                   (m->inbuf[2] << 8) | m->inbuf[3] | 0xfff00000;

  2838. 

  2839.         if (ff_mpa_check_header(header) < 0) { // Bad header, discard block

  2840.             *data_size = 0;

  2841.             return buf_size;

  2842.         }

  2843. 

  2844.         decode_header(m, header);

  2845.         mp_decode_frame(m, decoded_buf);

  2846. 

  2847.         n = MPA_FRAME_SIZE * m->nb_channels;

  2848.         out_size += n * sizeof(OUT_INT);

  2849.         if(s->frames > 1) {

  2850.             /* interleave output data */

  2851.             bp = out_samples + coff[fr];

  2852.             if(m->nb_channels == 1) {

  2853.                 for(j = 0; j < n; j++) {

  2854.                     *bp = decoded_buf[j];

  2855.                     bp += off;

  2856.                 }

  2857.             } else {

  2858.                 for(j = 0; j < n; j++) {

  2859.                     bp[0] = decoded_buf[j++];

  2860.                     bp[1] = decoded_buf[j];

  2861.                     bp += off;

  2862.                 }

  2863.             }

  2864.         }

  2865.     }

  2866. 

  2867.     /* update codec info */

  2868.     avctx->sample_rate = s->mp3decctx[0]->sample_rate;

  2869.     avctx->frame_size= buf_size;

  2870.     avctx->bit_rate = 0;

  2871.     for (i = 0; i < s->frames; i++)

  2872.         avctx->bit_rate += s->mp3decctx[i]->bit_rate;

  2873. 

  2874.     *data_size = out_size;

  2875.     return buf_size;

  2876. }

  2877. 

  2878. 

  2879. AVCodec mp2_decoder =

  2880. {

  2881.     "mp2",

  2882.     CODEC_TYPE_AUDIO,

  2883.     CODEC_ID_MP2,

  2884.     sizeof(MPADecodeContext),

  2885.     decode_init,

  2886.     NULL,

  2887.     NULL,

  2888.     decode_frame,

  2889.     CODEC_CAP_PARSE_ONLY,

  2890. };

  2891. 

  2892. AVCodec mp3_decoder =

  2893. {

  2894.     "mp3",

  2895.     CODEC_TYPE_AUDIO,

  2896.     CODEC_ID_MP3,

  2897.     sizeof(MPADecodeContext),

  2898.     decode_init,

  2899.     NULL,

  2900.     NULL,

  2901.     decode_frame,

  2902.     CODEC_CAP_PARSE_ONLY,

  2903. };

  2904. 

  2905. AVCodec mp3adu_decoder =

  2906. {

  2907.     "mp3adu",

  2908.     CODEC_TYPE_AUDIO,

  2909.     CODEC_ID_MP3ADU,

  2910.     sizeof(MPADecodeContext),

  2911.     decode_init,

  2912.     NULL,

  2913.     NULL,

  2914.     decode_frame_adu,

  2915.     CODEC_CAP_PARSE_ONLY,

  2916. };

  2917. 

  2918. AVCodec mp3on4_decoder =

  2919. {

  2920.     "mp3on4",

  2921.     CODEC_TYPE_AUDIO,

  2922.     CODEC_ID_MP3ON4,

  2923.     sizeof(MP3On4DecodeContext),

  2924.     decode_init_mp3on4,

  2925.     NULL,

  2926.     decode_close_mp3on4,

  2927.     decode_frame_mp3on4,

  2928.     0

  2929. };