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

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

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

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

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

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

  52. 

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

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

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

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

  57. }

  58. 

  59. /****************/

  60. 

  61. #define HEADER_SIZE 4

  62. #define BACKSTEP_SIZE 512

  63. 

  64. struct GranuleDef;

  65. 

  66. typedef struct MPADecodeContext {

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

  68.     int inbuf_index;

  69.     uint8_t *inbuf_ptr, *inbuf;

  70.     int frame_size;

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

  72.                                    (zero if currently unknown) */

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

  74.     uint32_t free_format_next_header;

  75.     int error_protection;

  76.     int layer;

  77.     int sample_rate;

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

  79.     int bit_rate;

  80.     int old_frame_size;

  81.     GetBitContext gb;

  82.     int nb_channels;

  83.     int mode;

  84.     int mode_ext;

  85.     int lsf;

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

  87.     int synth_buf_offset[MPA_MAX_CHANNELS];

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

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

  90. #ifdef DEBUG

  91.     int frame_count;

  92. #endif

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

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

  95.     unsigned int dither_state;

  96. } MPADecodeContext;

  97. 

  98. /**

  99.  * Context for MP3On4 decoder

  100.  */

  101. typedef struct MP3On4DecodeContext {

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

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

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

  105. } MP3On4DecodeContext;

  106. 

  107. /* layer 3 "granule" */

  108. typedef struct GranuleDef {

  109.     uint8_t scfsi;

  110.     int part2_3_length;

  111.     int big_values;

  112.     int global_gain;

  113.     int scalefac_compress;

  114.     uint8_t block_type;

  115.     uint8_t switch_point;

  116.     int table_select[3];

  117.     int subblock_gain[3];

  118.     uint8_t scalefac_scale;

  119.     uint8_t count1table_select;

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

  121.     int preflag;

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

  123.     uint8_t scale_factors[40];

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

  125. } GranuleDef;

  126. 

  127. #define MODE_EXT_MS_STEREO 2

  128. #define MODE_EXT_I_STEREO  1

  129. 

  130. /* layer 3 huffman tables */

  131. typedef struct HuffTable {

  132.     int xsize;

  133.     const uint8_t *bits;

  134.     const uint16_t *codes;

  135. } HuffTable;

  136. 

  137. #include "mpegaudiodectab.h"

  138. 

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

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

  141. 

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

  143. static VLC huff_vlc[16];

  144. static uint8_t *huff_code_table[16];

  145. static VLC huff_quad_vlc[2];

  146. /* computed from band_size_long */

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

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

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

  150. static int8_t  *table_4_3_exp;

  151. static uint32_t *table_4_3_value;

  152. /* intensity stereo coef table */

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

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

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

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

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

  158. 

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

  160. static uint16_t scale_factor_modshift[64];

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

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

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

  164. 

  165. #define SCALE_GEN(v) \

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

  167. 

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

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

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

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

  172. };

  173. 

  174. void ff_mpa_synth_init(MPA_INT *window);

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

  176. 

  177. /* layer 1 unscaling */

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

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

  180. {

  181.     int shift, mod;

  182.     int64_t val;

  183. 

  184.     shift = scale_factor_modshift[scale_factor];

  185.     mod = shift & 3;

  186.     shift >>= 2;

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

  188.     shift += n;

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

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

  191. }

  192. 

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

  194. {

  195.     int shift, mod, val;

  196. 

  197.     shift = scale_factor_modshift[scale_factor];

  198.     mod = shift & 3;

  199.     shift >>= 2;

  200. 

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

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

  203.     if (shift > 0)

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

  205.     return val;

  206. }

  207. 

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

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

  210. {

  211.     unsigned int m;

  212.     int e;

  213. 

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

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

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

  217.     assert(e>=1);

  218.     if (e > 31)

  219.         return 0;

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

  221. 

  222.     return m;

  223. }

  224. 

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

  226. #define DEV_ORDER 13

  227. 

  228. #define POW_FRAC_BITS 24

  229. #define POW_FRAC_ONE    (1 << POW_FRAC_BITS)

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

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

  232. 

  233. static int dev_4_3_coefs[DEV_ORDER];

  234. 

  235. #if 0 /* unused */

  236. static int pow_mult3[3] = {

  237.     POW_FIX(1.0),

  238.     POW_FIX(1.25992104989487316476),

  239.     POW_FIX(1.58740105196819947474),

  240. };

  241. #endif

  242. 

  243. static void int_pow_init(void)

  244. {

  245.     int i, a;

  246. 

  247.     a = POW_FIX(1.0);

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

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

  250.         dev_4_3_coefs[i] = a;

  251.     }

  252. }

  253. 

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

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

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

  257. {

  258.     int e, er, eq, j;

  259.     int a, a1;

  260. 

  261.     /* renormalize */

  262.     a = i;

  263.     e = POW_FRAC_BITS;

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

  265.         a = a << 1;

  266.         e--;

  267.     }

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

  269.     a1 = 0;

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

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

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

  273.     /* exponent compute (exact) */

  274.     e = e * 4;

  275.     er = e % 3;

  276.     eq = e / 3;

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

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

  279.         a = a >> 1;

  280.         eq++;

  281.     }

  282.     /* convert to float */

  283.     while (a < POW_FRAC_ONE) {

  284.         a = a << 1;

  285.         eq--;

  286.     }

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

  288. #if POW_FRAC_BITS > FRAC_BITS

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

  290.     /* correct overflow */

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

  292.         a = a >> 1;

  293.         eq++;

  294.     }

  295. #endif

  296.     *exp_ptr = eq;

  297.     return a;

  298. }

  299. #endif

  300. 

  301. static int decode_init(AVCodecContext * avctx)

  302. {

  303.     MPADecodeContext *s = avctx->priv_data;

  304.     static int init=0;

  305.     int i, j, k;

  306. 

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

  308.     avctx->sample_fmt= SAMPLE_FMT_S32;

  309. #else

  310.     avctx->sample_fmt= SAMPLE_FMT_S16;

  311. #endif

  312. 

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

  314.         s->compute_antialias= compute_antialias_integer;

  315.     else

  316.         s->compute_antialias= compute_antialias_float;

  317. 

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

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

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

  321.             int shift, mod;

  322.             /* 1.0 (i = 3) is normalized to 2 ^ FRAC_BITS */

  323.             shift = (i / 3);

  324.             mod = i % 3;

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

  326.         }

  327. 

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

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

  330.             int n, norm;

  331.             n = i + 2;

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

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

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

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

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

  337.                     i, norm,

  338.                     scale_factor_mult[i][0],

  339.                     scale_factor_mult[i][1],

  340.                     scale_factor_mult[i][2]);

  341.         }

  342. 

  343.         ff_mpa_synth_init(window);

  344. 

  345.         /* huffman decode tables */

  346.         huff_code_table[0] = NULL;

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

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

  349.             int xsize, x, y;

  350.             unsigned int n;

  351.             uint8_t *code_table;

  352. 

  353.             xsize = h->xsize;

  354.             n = xsize * xsize;

  355.             /* XXX: fail test */

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

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

  358. 

  359.             code_table = av_mallocz(n);

  360.             j = 0;

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

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

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

  364.             }

  365.             huff_code_table[i] = code_table;

  366.         }

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

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

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

  370.         }

  371. 

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

  373.             k = 0;

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

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

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

  377.             }

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

  379.         }

  380. 

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

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

  383.         if(!table_4_3_exp)

  384.             return -1;

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

  386.         if(!table_4_3_value)

  387.             return -1;

  388. 

  389.         int_pow_init();

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

  391.             double f, fm;

  392.             int e, m;

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

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

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

  396.             e+= FRAC_BITS - 31 + 5;

  397. 

  398.             /* normalized to FRAC_BITS */

  399.             table_4_3_value[i] = m;

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

  401.             table_4_3_exp[i] = -e;

  402.         }

  403. 

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

  405.             float f;

  406.             int v;

  407.             if (i != 6) {

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

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

  410.             } else {

  411.                 v = FIXR(1.0);

  412.             }

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

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

  415.         }

  416.         /* invalid values */

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

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

  419. 

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

  421.             double f;

  422.             int e, k;

  423. 

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

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

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

  427.                 k = i & 1;

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

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

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

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

  432.             }

  433.         }

  434. 

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

  436.             float ci, cs, ca;

  437.             ci = ci_table[i];

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

  439.             ca = cs * ci;

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

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

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

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

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

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

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

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

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

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

  450.         }

  451. 

  452.         /* compute mdct windows */

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

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

  455.                 double d;

  456. 

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

  458.                     continue;

  459. 

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

  461.                 if(j==1){

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

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

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

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

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

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

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

  469.                 }

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

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

  472. 

  473.                 if(j==2)

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

  475.                 else

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

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

  478.             }

  479.         }

  480. 

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

  482.            the sign of the right window coefs */

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

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

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

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

  487.             }

  488.         }

  489. 

  490. #if defined(DEBUG)

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

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

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

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

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

  496.         }

  497. #endif

  498.         init = 1;

  499.     }

  500. 

  501.     s->inbuf_index = 0;

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

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

  504. #ifdef DEBUG

  505.     s->frame_count = 0;

  506. #endif

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

  508.         s->adu_mode = 1;

  509.     return 0;

  510. }

  511. 

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

  513. 

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

  515. 

  516. #define COS0_0  FIXR(0.50060299823519630134)

  517. #define COS0_1  FIXR(0.50547095989754365998)

  518. #define COS0_2  FIXR(0.51544730992262454697)

  519. #define COS0_3  FIXR(0.53104259108978417447)

  520. #define COS0_4  FIXR(0.55310389603444452782)

  521. #define COS0_5  FIXR(0.58293496820613387367)

  522. #define COS0_6  FIXR(0.62250412303566481615)

  523. #define COS0_7  FIXR(0.67480834145500574602)

  524. #define COS0_8  FIXR(0.74453627100229844977)

  525. #define COS0_9  FIXR(0.83934964541552703873)

  526. #define COS0_10 FIXR(0.97256823786196069369)

  527. #define COS0_11 FIXR(1.16943993343288495515)

  528. #define COS0_12 FIXR(1.48416461631416627724)

  529. #define COS0_13 FIXR(2.05778100995341155085)

  530. #define COS0_14 FIXR(3.40760841846871878570)

  531. #define COS0_15 FIXR(10.19000812354805681150)

  532. 

  533. #define COS1_0 FIXR(0.50241928618815570551)

  534. #define COS1_1 FIXR(0.52249861493968888062)

  535. #define COS1_2 FIXR(0.56694403481635770368)

  536. #define COS1_3 FIXR(0.64682178335999012954)

  537. #define COS1_4 FIXR(0.78815462345125022473)

  538. #define COS1_5 FIXR(1.06067768599034747134)

  539. #define COS1_6 FIXR(1.72244709823833392782)

  540. #define COS1_7 FIXR(5.10114861868916385802)

  541. 

  542. #define COS2_0 FIXR(0.50979557910415916894)

  543. #define COS2_1 FIXR(0.60134488693504528054)

  544. #define COS2_2 FIXR(0.89997622313641570463)

  545. #define COS2_3 FIXR(2.56291544774150617881)

  546. 

  547. #define COS3_0 FIXR(0.54119610014619698439)

  548. #define COS3_1 FIXR(1.30656296487637652785)

  549. 

  550. #define COS4_0 FIXR(0.70710678118654752439)

  551. 

  552. /* butterfly operator */

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

  554. {\

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

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

  557.     tab[a] = tmp0;\

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

  559. }

  560. 

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

  562. {\

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

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

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

  566. }

  567. 

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

  569. {\

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

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

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

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

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

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

  576. }

  577. 

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

  579. 

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

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

  582. {

  583.     int tmp0, tmp1;

  584. 

  585. 

  586.     /* pass 1 */

  587.     BF(0, 31, COS0_0);

  588.     BF(15, 16, COS0_15);

  589.     /* pass 2 */

  590.     BF(0, 15, COS1_0);

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

  592.     /* pass 1 */

  593.     BF(7, 24, COS0_7);

  594.     BF(8, 23, COS0_8);

  595.     /* pass 2 */

  596.     BF(7,  8, COS1_7);

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

  598.     /* pass 3 */

  599.     BF(0, 7, COS2_0);

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

  601.     BF(16, 23, COS2_0);

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

  603.     /* pass 1 */

  604.     BF(3, 28, COS0_3);

  605.     BF(12, 19, COS0_12);

  606.     /* pass 2 */

  607.     BF(3, 12, COS1_3);

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

  609.     /* pass 1 */

  610.     BF(4, 27, COS0_4);

  611.     BF(11, 20, COS0_11);

  612.     /* pass 2 */

  613.     BF(4, 11, COS1_4);

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

  615.     /* pass 3 */

  616.     BF(3, 4, COS2_3);

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

  618.     BF(19, 20, COS2_3);

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

  620.     /* pass 4 */

  621.     BF(0, 3, COS3_0);

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

  623.     BF(8, 11, COS3_0);

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

  625.     BF(16, 19, COS3_0);

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

  627.     BF(24, 27, COS3_0);

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

  629. 

  630. 

  631. 

  632.     /* pass 1 */

  633.     BF(1, 30, COS0_1);

  634.     BF(14, 17, COS0_14);

  635.     /* pass 2 */

  636.     BF(1, 14, COS1_1);

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

  638.     /* pass 1 */

  639.     BF(6, 25, COS0_6);

  640.     BF(9, 22, COS0_9);

  641.     /* pass 2 */

  642.     BF(6,  9, COS1_6);

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

  644.     /* pass 3 */

  645.     BF(1, 6, COS2_1);

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

  647.     BF(17, 22, COS2_1);

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

  649. 

  650.     /* pass 1 */

  651.     BF(2, 29, COS0_2);

  652.     BF(13, 18, COS0_13);

  653.     /* pass 2 */

  654.     BF(2, 13, COS1_2);

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

  656.     /* pass 1 */

  657.     BF(5, 26, COS0_5);

  658.     BF(10, 21, COS0_10);

  659.     /* pass 2 */

  660.     BF(5, 10, COS1_5);

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

  662.     /* pass 3 */

  663.     BF(2, 5, COS2_2);

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

  665.     BF(18, 21, COS2_2);

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

  667.     /* pass 4 */

  668.     BF(1, 2, COS3_1);

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

  670.     BF(9, 10, COS3_1);

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

  672.     BF(17, 18, COS3_1);

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

  674.     BF(25, 26, COS3_1);

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

  676. 

  677.     /* pass 5 */

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

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

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

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

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

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

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

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

  686. 

  687.     /* pass 6 */

  688. 

  689.     ADD( 8, 12);

  690.     ADD(12, 10);

  691.     ADD(10, 14);

  692.     ADD(14,  9);

  693.     ADD( 9, 13);

  694.     ADD(13, 11);

  695.     ADD(11, 15);

  696. 

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  713. 

  714.     ADD(24, 28);

  715.     ADD(28, 26);

  716.     ADD(26, 30);

  717.     ADD(30, 25);

  718.     ADD(25, 29);

  719.     ADD(29, 27);

  720.     ADD(27, 31);

  721. 

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  738. }

  739. 

  740. #if FRAC_BITS <= 15

  741. 

  742. static inline int round_sample(int *sum)

  743. {

  744.     int sum1;

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

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

  747.     if (sum1 < OUT_MIN)

  748.         sum1 = OUT_MIN;

  749.     else if (sum1 > OUT_MAX)

  750.         sum1 = OUT_MAX;

  751.     return sum1;

  752. }

  753. 

  754. #if defined(ARCH_POWERPC_405)

  755. 

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

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

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

  759. 

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

  761. #define MULS(ra, rb) \

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

  763. 

  764. #else

  765. 

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

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

  768. 

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

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

  771. 

  772. #endif

  773. 

  774. #else

  775. 

  776. static inline int round_sample(int64_t *sum)

  777. {

  778.     int sum1;

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

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

  781.     if (sum1 < OUT_MIN)

  782.         sum1 = OUT_MIN;

  783.     else if (sum1 > OUT_MAX)

  784.         sum1 = OUT_MAX;

  785.     return sum1;

  786. }

  787. 

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

  789. 

  790. #endif

  791. 

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

  793. {                                               \

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

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

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

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

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

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

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

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

  802. }

  803. 

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

  805. {                                               \

  806.     int tmp;\

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  831. }

  832. 

  833. void ff_mpa_synth_init(MPA_INT *window)

  834. {

  835.     int i;

  836. 

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

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

  839.         int v;

  840.         v = mpa_enwindow[i];

  841. #if WFRAC_BITS < 16

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

  843. #endif

  844.         window[i] = v;

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

  846.             v = -v;

  847.         if (i != 0)

  848.             window[512 - i] = v;

  849.     }

  850. }

  851. 

  852. /* 32 sub band synthesis filter. Input: 32 sub band samples, Output:

  853.    32 samples. */

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

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

  856.                          MPA_INT *window, int *dither_state,

  857.                          OUT_INT *samples, int incr,

  858.                          int32_t sb_samples[SBLIMIT])

  859. {

  860.     int32_t tmp[32];

  861.     register MPA_INT *synth_buf;

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

  863.     int j, offset, v;

  864.     OUT_INT *samples2;

  865. #if FRAC_BITS <= 15

  866.     int sum, sum2;

  867. #else

  868.     int64_t sum, sum2;

  869. #endif

  870. 

  871.     dct32(tmp, sb_samples);

  872. 

  873.     offset = *synth_buf_offset;

  874.     synth_buf = synth_buf_ptr + offset;

  875. 

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

  877.         v = tmp[j];

  878. #if FRAC_BITS <= 15

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

  880.            sound */

  881.         if (v > 32767)

  882.             v = 32767;

  883.         else if (v < -32768)

  884.             v = -32768;

  885. #endif

  886.         synth_buf[j] = v;

  887.     }

  888.     /* copy to avoid wrap */

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

  890. 

  891.     samples2 = samples + 31 * incr;

  892.     w = window;

  893.     w2 = window + 31;

  894. 

  895.     sum = *dither_state;

  896.     p = synth_buf + 16;

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

  898.     p = synth_buf + 48;

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

  900.     *samples = round_sample(&sum);

  901.     samples += incr;

  902.     w++;

  903. 

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

  905.        access per two sample */

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

  907.         sum2 = 0;

  908.         p = synth_buf + 16 + j;

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

  910.         p = synth_buf + 48 - j;

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

  912. 

  913.         *samples = round_sample(&sum);

  914.         samples += incr;

  915.         sum += sum2;

  916.         *samples2 = round_sample(&sum);

  917.         samples2 -= incr;

  918.         w++;

  919.         w2--;

  920.     }

  921. 

  922.     p = synth_buf + 32;

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

  924.     *samples = round_sample(&sum);

  925.     *dither_state= sum;

  926. 

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

  928.     *synth_buf_offset = offset;

  929. }

  930. 

  931. #define C3 FIXHR(0.86602540378443864676/2)

  932. 

  933. /* 0.5 / cos(pi*(2*i+1)/36) */

  934. static const int icos36[9] = {

  935.     FIXR(0.50190991877167369479),

  936.     FIXR(0.51763809020504152469), //0

  937.     FIXR(0.55168895948124587824),

  938.     FIXR(0.61038729438072803416),

  939.     FIXR(0.70710678118654752439), //1

  940.     FIXR(0.87172339781054900991),

  941.     FIXR(1.18310079157624925896),

  942.     FIXR(1.93185165257813657349), //2

  943.     FIXR(5.73685662283492756461),

  944. };

  945. 

  946. /* 0.5 / cos(pi*(2*i+1)/36) */

  947. static const int icos36h[9] = {

  948.     FIXHR(0.50190991877167369479/2),

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

  950.     FIXHR(0.55168895948124587824/2),

  951.     FIXHR(0.61038729438072803416/2),

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

  953.     FIXHR(0.87172339781054900991/2),

  954.     FIXHR(1.18310079157624925896/4),

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

  956. //    FIXHR(5.73685662283492756461),

  957. };

  958. 

  959. /* 12 points IMDCT. We compute it "by hand" by factorizing obvious

  960.    cases. */

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

  962. {

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

  964. 

  965.     in0= in[0*3];

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

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

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

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

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

  971.     in5 += in3;

  972.     in3 += in1;

  973. 

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

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

  976. 

  977.     t1 = in0 - in4;

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

  979. 

  980.     out[ 7]=

  981.     out[10]= t1 + t2;

  982.     out[ 1]=

  983.     out[ 4]= t1 - t2;

  984. 

  985.     in0 += in4>>1;

  986.     in4 = in0 + in2;

  987.     in5 += 2*in1;

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

  989.     out[ 8]=

  990.     out[ 9]= in4 + in1;

  991.     out[ 2]=

  992.     out[ 3]= in4 - in1;

  993. 

  994.     in0 -= in2;

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

  996.     out[ 0]=

  997.     out[ 5]= in0 - in5;

  998.     out[ 6]=

  999.     out[11]= in0 + in5;

  1000. }

  1001. 

  1002. /* cos(pi*i/18) */

  1003. #define C1 FIXHR(0.98480775301220805936/2)

  1004. #define C2 FIXHR(0.93969262078590838405/2)

  1005. #define C3 FIXHR(0.86602540378443864676/2)

  1006. #define C4 FIXHR(0.76604444311897803520/2)

  1007. #define C5 FIXHR(0.64278760968653932632/2)

  1008. #define C6 FIXHR(0.5/2)

  1009. #define C7 FIXHR(0.34202014332566873304/2)

  1010. #define C8 FIXHR(0.17364817766693034885/2)

  1011. 

  1012. 

  1013. /* using Lee like decomposition followed by hand coded 9 points DCT */

  1014. static void imdct36(int *out, int *buf, int *in, int *win)

  1015. {

  1016.     int i, j, t0, t1, t2, t3, s0, s1, s2, s3;

  1017.     int tmp[18], *tmp1, *in1;

  1018. 

  1019.     for(i=17;i>=1;i--)

  1020.         in[i] += in[i-1];

  1021.     for(i=17;i>=3;i-=2)

  1022.         in[i] += in[i-2];

  1023. 

  1024.     for(j=0;j<2;j++) {

  1025.         tmp1 = tmp + j;

  1026.         in1 = in + j;

  1027. #if 0

  1028. //more accurate but slower

  1029.         int64_t t0, t1, t2, t3;

  1030.         t2 = in1[2*4] + in1[2*8] - in1[2*2];

  1031. 

  1032.         t3 = (in1[2*0] + (int64_t)(in1[2*6]>>1))<<32;

  1033.         t1 = in1[2*0] - in1[2*6];

  1034.         tmp1[ 6] = t1 - (t2>>1);

  1035.         tmp1[16] = t1 + t2;

  1036. 

  1037.         t0 = MUL64(2*(in1[2*2] + in1[2*4]),    C2);

  1038.         t1 = MUL64(   in1[2*4] - in1[2*8] , -2*C8);

  1039.         t2 = MUL64(2*(in1[2*2] + in1[2*8]),   -C4);

  1040. 

  1041.         tmp1[10] = (t3 - t0 - t2) >> 32;

  1042.         tmp1[ 2] = (t3 + t0 + t1) >> 32;

  1043.         tmp1[14] = (t3 + t2 - t1) >> 32;

  1044. 

  1045.         tmp1[ 4] = MULH(2*(in1[2*5] + in1[2*7] - in1[2*1]), -C3);

  1046.         t2 = MUL64(2*(in1[2*1] + in1[2*5]),    C1);

  1047.         t3 = MUL64(   in1[2*5] - in1[2*7] , -2*C7);

  1048.         t0 = MUL64(2*in1[2*3], C3);

  1049. 

  1050.         t1 = MUL64(2*(in1[2*1] + in1[2*7]),   -C5);

  1051. 

  1052.         tmp1[ 0] = (t2 + t3 + t0) >> 32;

  1053.         tmp1[12] = (t2 + t1 - t0) >> 32;

  1054.         tmp1[ 8] = (t3 - t1 - t0) >> 32;

  1055. #else

  1056.         t2 = in1[2*4] + in1[2*8] - in1[2*2];

  1057. 

  1058.         t3 = in1[2*0] + (in1[2*6]>>1);

  1059.         t1 = in1[2*0] - in1[2*6];

  1060.         tmp1[ 6] = t1 - (t2>>1);

  1061.         tmp1[16] = t1 + t2;

  1062. 

  1063.         t0 = MULH(2*(in1[2*2] + in1[2*4]),    C2);

  1064.         t1 = MULH(   in1[2*4] - in1[2*8] , -2*C8);

  1065.         t2 = MULH(2*(in1[2*2] + in1[2*8]),   -C4);

  1066. 

  1067.         tmp1[10] = t3 - t0 - t2;

  1068.         tmp1[ 2] = t3 + t0 + t1;

  1069.         tmp1[14] = t3 + t2 - t1;

  1070. 

  1071.         tmp1[ 4] = MULH(2*(in1[2*5] + in1[2*7] - in1[2*1]), -C3);

  1072.         t2 = MULH(2*(in1[2*1] + in1[2*5]),    C1);

  1073.         t3 = MULH(   in1[2*5] - in1[2*7] , -2*C7);

  1074.         t0 = MULH(2*in1[2*3], C3);

  1075. 

  1076.         t1 = MULH(2*(in1[2*1] + in1[2*7]),   -C5);

  1077. 

  1078.         tmp1[ 0] = t2 + t3 + t0;

  1079.         tmp1[12] = t2 + t1 - t0;

  1080.         tmp1[ 8] = t3 - t1 - t0;

  1081. #endif

  1082.     }

  1083. 

  1084.     i = 0;

  1085.     for(j=0;j<4;j++) {

  1086.         t0 = tmp[i];

  1087.         t1 = tmp[i + 2];

  1088.         s0 = t1 + t0;

  1089.         s2 = t1 - t0;

  1090. 

  1091.         t2 = tmp[i + 1];

  1092.         t3 = tmp[i + 3];

  1093.         s1 = MULH(2*(t3 + t2), icos36h[j]);

  1094.         s3 = MULL(t3 - t2, icos36[8 - j]);

  1095. 

  1096.         t0 = s0 + s1;

  1097.         t1 = s0 - s1;

  1098.         out[(9 + j)*SBLIMIT] =  MULH(t1, win[9 + j]) + buf[9 + j];

  1099.         out[(8 - j)*SBLIMIT] =  MULH(t1, win[8 - j]) + buf[8 - j];

  1100.         buf[9 + j] = MULH(t0, win[18 + 9 + j]);

  1101.         buf[8 - j] = MULH(t0, win[18 + 8 - j]);

  1102. 

  1103.         t0 = s2 + s3;

  1104.         t1 = s2 - s3;

  1105.         out[(9 + 8 - j)*SBLIMIT] =  MULH(t1, win[9 + 8 - j]) + buf[9 + 8 - j];

  1106.         out[(        j)*SBLIMIT] =  MULH(t1, win[        j]) + buf[        j];

  1107.         buf[9 + 8 - j] = MULH(t0, win[18 + 9 + 8 - j]);

  1108.         buf[      + j] = MULH(t0, win[18         + j]);

  1109.         i += 4;

  1110.     }

  1111. 

  1112.     s0 = tmp[16];

  1113.     s1 = MULH(2*tmp[17], icos36h[4]);

  1114.     t0 = s0 + s1;

  1115.     t1 = s0 - s1;

  1116.     out[(9 + 4)*SBLIMIT] =  MULH(t1, win[9 + 4]) + buf[9 + 4];

  1117.     out[(8 - 4)*SBLIMIT] =  MULH(t1, win[8 - 4]) + buf[8 - 4];

  1118.     buf[9 + 4] = MULH(t0, win[18 + 9 + 4]);

  1119.     buf[8 - 4] = MULH(t0, win[18 + 8 - 4]);

  1120. }

  1121. 

  1122. /* header decoding. MUST check the header before because no

  1123.    consistency check is done there. Return 1 if free format found and

  1124.    that the frame size must be computed externally */

  1125. static int decode_header(MPADecodeContext *s, uint32_t header)

  1126. {

  1127.     int sample_rate, frame_size, mpeg25, padding;

  1128.     int sample_rate_index, bitrate_index;

  1129.     if (header & (1<<20)) {

  1130.         s->lsf = (header & (1<<19)) ? 0 : 1;

  1131.         mpeg25 = 0;

  1132.     } else {

  1133.         s->lsf = 1;

  1134.         mpeg25 = 1;

  1135.     }

  1136. 

  1137.     s->layer = 4 - ((header >> 17) & 3);

  1138.     /* extract frequency */

  1139.     sample_rate_index = (header >> 10) & 3;

  1140.     sample_rate = mpa_freq_tab[sample_rate_index] >> (s->lsf + mpeg25);

  1141.     sample_rate_index += 3 * (s->lsf + mpeg25);

  1142.     s->sample_rate_index = sample_rate_index;

  1143.     s->error_protection = ((header >> 16) & 1) ^ 1;

  1144.     s->sample_rate = sample_rate;

  1145. 

  1146.     bitrate_index = (header >> 12) & 0xf;

  1147.     padding = (header >> 9) & 1;

  1148.     //extension = (header >> 8) & 1;

  1149.     s->mode = (header >> 6) & 3;

  1150.     s->mode_ext = (header >> 4) & 3;

  1151.     //copyright = (header >> 3) & 1;

  1152.     //original = (header >> 2) & 1;

  1153.     //emphasis = header & 3;

  1154. 

  1155.     if (s->mode == MPA_MONO)

  1156.         s->nb_channels = 1;

  1157.     else

  1158.         s->nb_channels = 2;

  1159. 

  1160.     if (bitrate_index != 0) {

  1161.         frame_size = mpa_bitrate_tab[s->lsf][s->layer - 1][bitrate_index];

  1162.         s->bit_rate = frame_size * 1000;

  1163.         switch(s->layer) {

  1164.         case 1:

  1165.             frame_size = (frame_size * 12000) / sample_rate;

  1166.             frame_size = (frame_size + padding) * 4;

  1167.             break;

  1168.         case 2:

  1169.             frame_size = (frame_size * 144000) / sample_rate;

  1170.             frame_size += padding;

  1171.             break;

  1172.         default:

  1173.         case 3:

  1174.             frame_size = (frame_size * 144000) / (sample_rate << s->lsf);

  1175.             frame_size += padding;

  1176.             break;

  1177.         }

  1178.         s->frame_size = frame_size;

  1179.     } else {

  1180.         /* if no frame size computed, signal it */

  1181.         if (!s->free_format_frame_size)

  1182.             return 1;

  1183.         /* free format: compute bitrate and real frame size from the

  1184.            frame size we extracted by reading the bitstream */

  1185.         s->frame_size = s->free_format_frame_size;

  1186.         switch(s->layer) {

  1187.         case 1:

  1188.             s->frame_size += padding  * 4;

  1189.             s->bit_rate = (s->frame_size * sample_rate) / 48000;

  1190.             break;

  1191.         case 2:

  1192.             s->frame_size += padding;

  1193.             s->bit_rate = (s->frame_size * sample_rate) / 144000;

  1194.             break;

  1195.         default:

  1196.         case 3:

  1197.             s->frame_size += padding;

  1198.             s->bit_rate = (s->frame_size * (sample_rate << s->lsf)) / 144000;

  1199.             break;

  1200.         }

  1201.     }

  1202. 

  1203. #if defined(DEBUG)

  1204.     dprintf("layer%d, %d Hz, %d kbits/s, ",

  1205.            s->layer, s->sample_rate, s->bit_rate);

  1206.     if (s->nb_channels == 2) {

  1207.         if (s->layer == 3) {

  1208.             if (s->mode_ext & MODE_EXT_MS_STEREO)

  1209.                 dprintf("ms-");

  1210.             if (s->mode_ext & MODE_EXT_I_STEREO)

  1211.                 dprintf("i-");

  1212.         }

  1213.         dprintf("stereo");

  1214.     } else {

  1215.         dprintf("mono");

  1216.     }

  1217.     dprintf("\n");

  1218. #endif

  1219.     return 0;

  1220. }

  1221. 

  1222. /* useful helper to get mpeg audio stream infos. Return -1 if error in

  1223.    header, otherwise the coded frame size in bytes */

  1224. int mpa_decode_header(AVCodecContext *avctx, uint32_t head)

  1225. {

  1226.     MPADecodeContext s1, *s = &s1;

  1227.     memset( s, 0, sizeof(MPADecodeContext) );

  1228. 

  1229.     if (ff_mpa_check_header(head) != 0)

  1230.         return -1;

  1231. 

  1232.     if (decode_header(s, head) != 0) {

  1233.         return -1;

  1234.     }

  1235. 

  1236.     switch(s->layer) {

  1237.     case 1:

  1238.         avctx->frame_size = 384;

  1239.         break;

  1240.     case 2:

  1241.         avctx->frame_size = 1152;

  1242.         break;

  1243.     default:

  1244.     case 3:

  1245.         if (s->lsf)

  1246.             avctx->frame_size = 576;

  1247.         else

  1248.             avctx->frame_size = 1152;

  1249.         break;

  1250.     }

  1251. 

  1252.     avctx->sample_rate = s->sample_rate;

  1253.     avctx->channels = s->nb_channels;

  1254.     avctx->bit_rate = s->bit_rate;

  1255.     avctx->sub_id = s->layer;

  1256.     return s->frame_size;

  1257. }

  1258. 

  1259. /* return the number of decoded frames */

  1260. static int mp_decode_layer1(MPADecodeContext *s)

  1261. {

  1262.     int bound, i, v, n, ch, j, mant;

  1263.     uint8_t allocation[MPA_MAX_CHANNELS][SBLIMIT];

  1264.     uint8_t scale_factors[MPA_MAX_CHANNELS][SBLIMIT];

  1265. 

  1266.     if (s->mode == MPA_JSTEREO)

  1267.         bound = (s->mode_ext + 1) * 4;

  1268.     else

  1269.         bound = SBLIMIT;

  1270. 

  1271.     /* allocation bits */

  1272.     for(i=0;i<bound;i++) {

  1273.         for(ch=0;ch<s->nb_channels;ch++) {

  1274.             allocation[ch][i] = get_bits(&s->gb, 4);

  1275.         }

  1276.     }

  1277.     for(i=bound;i<SBLIMIT;i++) {

  1278.         allocation[0][i] = get_bits(&s->gb, 4);

  1279.     }

  1280. 

  1281.     /* scale factors */

  1282.     for(i=0;i<bound;i++) {

  1283.         for(ch=0;ch<s->nb_channels;ch++) {

  1284.             if (allocation[ch][i])

  1285.                 scale_factors[ch][i] = get_bits(&s->gb, 6);

  1286.         }

  1287.     }

  1288.     for(i=bound;i<SBLIMIT;i++) {

  1289.         if (allocation[0][i]) {

  1290.             scale_factors[0][i] = get_bits(&s->gb, 6);

  1291.             scale_factors[1][i] = get_bits(&s->gb, 6);

  1292.         }

  1293.     }

  1294. 

  1295.     /* compute samples */

  1296.     for(j=0;j<12;j++) {

  1297.         for(i=0;i<bound;i++) {

  1298.             for(ch=0;ch<s->nb_channels;ch++) {

  1299.                 n = allocation[ch][i];

  1300.                 if (n) {

  1301.                     mant = get_bits(&s->gb, n + 1);

  1302.                     v = l1_unscale(n, mant, scale_factors[ch][i]);

  1303.                 } else {

  1304.                     v = 0;

  1305.                 }

  1306.                 s->sb_samples[ch][j][i] = v;

  1307.             }

  1308.         }

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

  1310.             n = allocation[0][i];

  1311.             if (n) {

  1312.                 mant = get_bits(&s->gb, n + 1);

  1313.                 v = l1_unscale(n, mant, scale_factors[0][i]);

  1314.                 s->sb_samples[0][j][i] = v;

  1315.                 v = l1_unscale(n, mant, scale_factors[1][i]);

  1316.                 s->sb_samples[1][j][i] = v;

  1317.             } else {

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

  1319.                 s->sb_samples[1][j][i] = 0;

  1320.             }

  1321.         }

  1322.     }

  1323.     return 12;

  1324. }

  1325. 

  1326. /* bitrate is in kb/s */

  1327. int l2_select_table(int bitrate, int nb_channels, int freq, int lsf)

  1328. {

  1329.     int ch_bitrate, table;

  1330. 

  1331.     ch_bitrate = bitrate / nb_channels;

  1332.     if (!lsf) {

  1333.         if ((freq == 48000 && ch_bitrate >= 56) ||

  1334.             (ch_bitrate >= 56 && ch_bitrate <= 80))

  1335.             table = 0;

  1336.         else if (freq != 48000 && ch_bitrate >= 96)

  1337.             table = 1;

  1338.         else if (freq != 32000 && ch_bitrate <= 48)

  1339.             table = 2;

  1340.         else

  1341.             table = 3;

  1342.     } else {

  1343.         table = 4;

  1344.     }

  1345.     return table;

  1346. }

  1347. 

  1348. static int mp_decode_layer2(MPADecodeContext *s)

  1349. {

  1350.     int sblimit; /* number of used subbands */

  1351.     const unsigned char *alloc_table;

  1352.     int table, bit_alloc_bits, i, j, ch, bound, v;

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

  1354.     unsigned char scale_code[MPA_MAX_CHANNELS][SBLIMIT];

  1355.     unsigned char scale_factors[MPA_MAX_CHANNELS][SBLIMIT][3], *sf;

  1356.     int scale, qindex, bits, steps, k, l, m, b;

  1357. 

  1358.     /* select decoding table */

  1359.     table = l2_select_table(s->bit_rate / 1000, s->nb_channels,

  1360.                             s->sample_rate, s->lsf);

  1361.     sblimit = sblimit_table[table];

  1362.     alloc_table = alloc_tables[table];

  1363. 

  1364.     if (s->mode == MPA_JSTEREO)

  1365.         bound = (s->mode_ext + 1) * 4;

  1366.     else

  1367.         bound = sblimit;

  1368. 

  1369.     dprintf("bound=%d sblimit=%d\n", bound, sblimit);

  1370. 

  1371.     /* sanity check */

  1372.     if( bound > sblimit ) bound = sblimit;

  1373. 

  1374.     /* parse bit allocation */

  1375.     j = 0;

  1376.     for(i=0;i<bound;i++) {

  1377.         bit_alloc_bits = alloc_table[j];

  1378.         for(ch=0;ch<s->nb_channels;ch++) {

  1379.             bit_alloc[ch][i] = get_bits(&s->gb, bit_alloc_bits);

  1380.         }

  1381.         j += 1 << bit_alloc_bits;

  1382.     }

  1383.     for(i=bound;i<sblimit;i++) {

  1384.         bit_alloc_bits = alloc_table[j];

  1385.         v = get_bits(&s->gb, bit_alloc_bits);

  1386.         bit_alloc[0][i] = v;

  1387.         bit_alloc[1][i] = v;

  1388.         j += 1 << bit_alloc_bits;

  1389.     }

  1390. 

  1391. #ifdef DEBUG

  1392.     {

  1393.         for(ch=0;ch<s->nb_channels;ch++) {

  1394.             for(i=0;i<sblimit;i++)

  1395.                 dprintf(" %d", bit_alloc[ch][i]);

  1396.             dprintf("\n");

  1397.         }

  1398.     }

  1399. #endif

  1400. 

  1401.     /* scale codes */

  1402.     for(i=0;i<sblimit;i++) {

  1403.         for(ch=0;ch<s->nb_channels;ch++) {

  1404.             if (bit_alloc[ch][i])

  1405.                 scale_code[ch][i] = get_bits(&s->gb, 2);

  1406.         }

  1407.     }

  1408. 

  1409.     /* scale factors */

  1410.     for(i=0;i<sblimit;i++) {

  1411.         for(ch=0;ch<s->nb_channels;ch++) {

  1412.             if (bit_alloc[ch][i]) {

  1413.                 sf = scale_factors[ch][i];

  1414.                 switch(scale_code[ch][i]) {

  1415.                 default:

  1416.                 case 0:

  1417.                     sf[0] = get_bits(&s->gb, 6);

  1418.                     sf[1] = get_bits(&s->gb, 6);

  1419.                     sf[2] = get_bits(&s->gb, 6);

  1420.                     break;

  1421.                 case 2:

  1422.                     sf[0] = get_bits(&s->gb, 6);

  1423.                     sf[1] = sf[0];

  1424.                     sf[2] = sf[0];

  1425.                     break;

  1426.                 case 1:

  1427.                     sf[0] = get_bits(&s->gb, 6);

  1428.                     sf[2] = get_bits(&s->gb, 6);

  1429.                     sf[1] = sf[0];

  1430.                     break;

  1431.                 case 3:

  1432.                     sf[0] = get_bits(&s->gb, 6);

  1433.                     sf[2] = get_bits(&s->gb, 6);

  1434.                     sf[1] = sf[2];

  1435.                     break;

  1436.                 }

  1437.             }

  1438.         }

  1439.     }

  1440. 

  1441. #ifdef DEBUG

  1442.     for(ch=0;ch<s->nb_channels;ch++) {

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

  1444.             if (bit_alloc[ch][i]) {

  1445.                 sf = scale_factors[ch][i];

  1446.                 dprintf(" %d %d %d", sf[0], sf[1], sf[2]);

  1447.             } else {

  1448.                 dprintf(" -");

  1449.             }

  1450.         }

  1451.         dprintf("\n");

  1452.     }

  1453. #endif

  1454. 

  1455.     /* samples */

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

  1457.         for(l=0;l<12;l+=3) {

  1458.             j = 0;

  1459.             for(i=0;i<bound;i++) {

  1460.                 bit_alloc_bits = alloc_table[j];

  1461.                 for(ch=0;ch<s->nb_channels;ch++) {

  1462.                     b = bit_alloc[ch][i];

  1463.                     if (b) {

  1464.                         scale = scale_factors[ch][i][k];

  1465.                         qindex = alloc_table[j+b];

  1466.                         bits = quant_bits[qindex];

  1467.                         if (bits < 0) {

  1468.                             /* 3 values at the same time */

  1469.                             v = get_bits(&s->gb, -bits);

  1470.                             steps = quant_steps[qindex];

  1471.                             s->sb_samples[ch][k * 12 + l + 0][i] =

  1472.                                 l2_unscale_group(steps, v % steps, scale);

  1473.                             v = v / steps;

  1474.                             s->sb_samples[ch][k * 12 + l + 1][i] =

  1475.                                 l2_unscale_group(steps, v % steps, scale);

  1476.                             v = v / steps;

  1477.                             s->sb_samples[ch][k * 12 + l + 2][i] =

  1478.                                 l2_unscale_group(steps, v, scale);

  1479.                         } else {

  1480.                             for(m=0;m<3;m++) {

  1481.                                 v = get_bits(&s->gb, bits);

  1482.                                 v = l1_unscale(bits - 1, v, scale);

  1483.                                 s->sb_samples[ch][k * 12 + l + m][i] = v;

  1484.                             }

  1485.                         }

  1486.                     } else {

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

  1488.                         s->sb_samples[ch][k * 12 + l + 1][i] = 0;

  1489.                         s->sb_samples[ch][k * 12 + l + 2][i] = 0;

  1490.                     }

  1491.                 }

  1492.                 /* next subband in alloc table */

  1493.                 j += 1 << bit_alloc_bits;

  1494.             }

  1495.             /* XXX: find a way to avoid this duplication of code */

  1496.             for(i=bound;i<sblimit;i++) {

  1497.                 bit_alloc_bits = alloc_table[j];

  1498.                 b = bit_alloc[0][i];

  1499.                 if (b) {

  1500.                     int mant, scale0, scale1;

  1501.                     scale0 = scale_factors[0][i][k];

  1502.                     scale1 = scale_factors[1][i][k];

  1503.                     qindex = alloc_table[j+b];

  1504.                     bits = quant_bits[qindex];

  1505.                     if (bits < 0) {

  1506.                         /* 3 values at the same time */

  1507.                         v = get_bits(&s->gb, -bits);

  1508.                         steps = quant_steps[qindex];

  1509.                         mant = v % steps;

  1510.                         v = v / steps;

  1511.                         s->sb_samples[0][k * 12 + l + 0][i] =

  1512.                             l2_unscale_group(steps, mant, scale0);

  1513.                         s->sb_samples[1][k * 12 + l + 0][i] =

  1514.                             l2_unscale_group(steps, mant, scale1);

  1515.                         mant = v % steps;

  1516.                         v = v / steps;

  1517.                         s->sb_samples[0][k * 12 + l + 1][i] =

  1518.                             l2_unscale_group(steps, mant, scale0);

  1519.                         s->sb_samples[1][k * 12 + l + 1][i] =

  1520.                             l2_unscale_group(steps, mant, scale1);

  1521.                         s->sb_samples[0][k * 12 + l + 2][i] =

  1522.                             l2_unscale_group(steps, v, scale0);

  1523.                         s->sb_samples[1][k * 12 + l + 2][i] =

  1524.                             l2_unscale_group(steps, v, scale1);

  1525.                     } else {

  1526.                         for(m=0;m<3;m++) {

  1527.                             mant = get_bits(&s->gb, bits);

  1528.                             s->sb_samples[0][k * 12 + l + m][i] =

  1529.                                 l1_unscale(bits - 1, mant, scale0);

  1530.                             s->sb_samples[1][k * 12 + l + m][i] =

  1531.                                 l1_unscale(bits - 1, mant, scale1);

  1532.                         }

  1533.                     }

  1534.                 } else {

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

  1536.                     s->sb_samples[0][k * 12 + l + 1][i] = 0;

  1537.                     s->sb_samples[0][k * 12 + l + 2][i] = 0;

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

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

  1540.                     s->sb_samples[1][k * 12 + l + 2][i] = 0;

  1541.                 }

  1542.                 /* next subband in alloc table */

  1543.                 j += 1 << bit_alloc_bits;

  1544.             }

  1545.             /* fill remaining samples to zero */

  1546.             for(i=sblimit;i<SBLIMIT;i++) {

  1547.                 for(ch=0;ch<s->nb_channels;ch++) {

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

  1549.                     s->sb_samples[ch][k * 12 + l + 1][i] = 0;

  1550.                     s->sb_samples[ch][k * 12 + l + 2][i] = 0;

  1551.                 }

  1552.             }

  1553.         }

  1554.     }

  1555.     return 3 * 12;

  1556. }

  1557. 

  1558. /*

  1559.  * Seek back in the stream for backstep bytes (at most 511 bytes)

  1560.  */

  1561. static void seek_to_maindata(MPADecodeContext *s, unsigned int backstep)

  1562. {

  1563.     uint8_t *ptr;

  1564. 

  1565.     /* compute current position in stream */

  1566.     ptr = (uint8_t *)(s->gb.buffer + (get_bits_count(&s->gb)>>3));

  1567. 

  1568.     /* copy old data before current one */

  1569.     ptr -= backstep;

  1570.     memcpy(ptr, s->inbuf1[s->inbuf_index ^ 1] +

  1571.            BACKSTEP_SIZE + s->old_frame_size - backstep, backstep);

  1572.     /* init get bits again */

  1573.     init_get_bits(&s->gb, ptr, (s->frame_size + backstep)*8);

  1574. 

  1575.     /* prepare next buffer */

  1576.     s->inbuf_index ^= 1;

  1577.     s->inbuf = &s->inbuf1[s->inbuf_index][BACKSTEP_SIZE];

  1578.     s->old_frame_size = s->frame_size;

  1579. }

  1580. 

  1581. static inline void lsf_sf_expand(int *slen,

  1582.                                  int sf, int n1, int n2, int n3)

  1583. {

  1584.     if (n3) {

  1585.         slen[3] = sf % n3;

  1586.         sf /= n3;

  1587.     } else {

  1588.         slen[3] = 0;

  1589.     }

  1590.     if (n2) {

  1591.         slen[2] = sf % n2;

  1592.         sf /= n2;

  1593.     } else {

  1594.         slen[2] = 0;

  1595.     }

  1596.     slen[1] = sf % n1;

  1597.     sf /= n1;

  1598.     slen[0] = sf;

  1599. }

  1600. 

  1601. static void exponents_from_scale_factors(MPADecodeContext *s,

  1602.                                          GranuleDef *g,

  1603.                                          int16_t *exponents)

  1604. {

  1605.     const uint8_t *bstab, *pretab;

  1606.     int len, i, j, k, l, v0, shift, gain, gains[3];

  1607.     int16_t *exp_ptr;

  1608. 

  1609.     exp_ptr = exponents;

  1610.     gain = g->global_gain - 210;

  1611.     shift = g->scalefac_scale + 1;

  1612. 

  1613.     bstab = band_size_long[s->sample_rate_index];

  1614.     pretab = mpa_pretab[g->preflag];

  1615.     for(i=0;i<g->long_end;i++) {

  1616.         v0 = gain - ((g->scale_factors[i] + pretab[i]) << shift);

  1617.         len = bstab[i];

  1618.         for(j=len;j>0;j--)

  1619.             *exp_ptr++ = v0;

  1620.     }

  1621. 

  1622.     if (g->short_start < 13) {

  1623.         bstab = band_size_short[s->sample_rate_index];

  1624.         gains[0] = gain - (g->subblock_gain[0] << 3);

  1625.         gains[1] = gain - (g->subblock_gain[1] << 3);

  1626.         gains[2] = gain - (g->subblock_gain[2] << 3);

  1627.         k = g->long_end;

  1628.         for(i=g->short_start;i<13;i++) {

  1629.             len = bstab[i];

  1630.             for(l=0;l<3;l++) {

  1631.                 v0 = gains[l] - (g->scale_factors[k++] << shift);

  1632.                 for(j=len;j>0;j--)

  1633.                 *exp_ptr++ = v0;

  1634.             }

  1635.         }

  1636.     }

  1637. }

  1638. 

  1639. /* handle n = 0 too */

  1640. static inline int get_bitsz(GetBitContext *s, int n)

  1641. {

  1642.     if (n == 0)

  1643.         return 0;

  1644.     else

  1645.         return get_bits(s, n);

  1646. }

  1647. 

  1648. static int huffman_decode(MPADecodeContext *s, GranuleDef *g,

  1649.                           int16_t *exponents, int end_pos)

  1650. {

  1651.     int s_index;

  1652.     int linbits, code, x, y, l, v, i, j, k, pos;

  1653.     GetBitContext last_gb;

  1654.     VLC *vlc;

  1655.     uint8_t *code_table;

  1656. 

  1657.     /* low frequencies (called big values) */

  1658.     s_index = 0;

  1659.     for(i=0;i<3;i++) {

  1660.         j = g->region_size[i];

  1661.         if (j == 0)

  1662.             continue;

  1663.         /* select vlc table */

  1664.         k = g->table_select[i];

  1665.         l = mpa_huff_data[k][0];

  1666.         linbits = mpa_huff_data[k][1];

  1667.         vlc = &huff_vlc[l];

  1668.         code_table = huff_code_table[l];

  1669. 

  1670.         /* read huffcode and compute each couple */

  1671.         for(;j>0;j--) {

  1672.             if (get_bits_count(&s->gb) >= end_pos)

  1673.                 break;

  1674.             if (code_table) {

  1675.                 code = get_vlc2(&s->gb, vlc->table, 8, 3);

  1676.                 if (code < 0)

  1677.                     return -1;

  1678.                 y = code_table[code];

  1679.                 x = y >> 4;

  1680.                 y = y & 0x0f;

  1681.             } else {

  1682.                 x = 0;

  1683.                 y = 0;

  1684.             }

  1685.             dprintf("region=%d n=%d x=%d y=%d exp=%d\n",

  1686.                     i, g->region_size[i] - j, x, y, exponents[s_index]);

  1687.             if (x) {

  1688.                 if (x == 15)

  1689.                     x += get_bitsz(&s->gb, linbits);

  1690.                 v = l3_unscale(x, exponents[s_index]);

  1691.                 if (get_bits1(&s->gb))

  1692.                     v = -v;

  1693.             } else {

  1694.                 v = 0;

  1695.             }

  1696.             g->sb_hybrid[s_index++] = v;

  1697.             if (y) {

  1698.                 if (y == 15)

  1699.                     y += get_bitsz(&s->gb, linbits);

  1700.                 v = l3_unscale(y, exponents[s_index]);

  1701.                 if (get_bits1(&s->gb))

  1702.                     v = -v;

  1703.             } else {

  1704.                 v = 0;

  1705.             }

  1706.             g->sb_hybrid[s_index++] = v;

  1707.         }

  1708.     }

  1709. 

  1710.     /* high frequencies */

  1711.     vlc = &huff_quad_vlc[g->count1table_select];

  1712.     last_gb.buffer = NULL;

  1713.     while (s_index <= 572) {

  1714.         pos = get_bits_count(&s->gb);

  1715.         if (pos >= end_pos) {

  1716.             if (pos > end_pos && last_gb.buffer != NULL) {

  1717.                 /* some encoders generate an incorrect size for this

  1718.                    part. We must go back into the data */

  1719.                 s_index -= 4;

  1720.                 s->gb = last_gb;

  1721.             }

  1722.             break;

  1723.         }

  1724.         last_gb= s->gb;

  1725. 

  1726.         code = get_vlc2(&s->gb, vlc->table, vlc->bits, 2);

  1727.         dprintf("t=%d code=%d\n", g->count1table_select, code);

  1728.         if (code < 0)

  1729.             return -1;

  1730.         for(i=0;i<4;i++) {

  1731.             if (code & (8 >> i)) {

  1732.                 /* non zero value. Could use a hand coded function for

  1733.                    'one' value */

  1734.                 v = l3_unscale(1, exponents[s_index]);

  1735.                 if(get_bits1(&s->gb))

  1736.                     v = -v;

  1737.             } else {

  1738.                 v = 0;

  1739.             }

  1740.             g->sb_hybrid[s_index++] = v;

  1741.         }

  1742.     }

  1743.     while (s_index < 576)

  1744.         g->sb_hybrid[s_index++] = 0;

  1745.     return 0;

  1746. }

  1747. 

  1748. /* Reorder short blocks from bitstream order to interleaved order. It

  1749.    would be faster to do it in parsing, but the code would be far more

  1750.    complicated */

  1751. static void reorder_block(MPADecodeContext *s, GranuleDef *g)

  1752. {

  1753.     int i, j, k, len;

  1754.     int32_t *ptr, *dst, *ptr1;

  1755.     int32_t tmp[576];

  1756. 

  1757.     if (g->block_type != 2)

  1758.         return;

  1759. 

  1760.     if (g->switch_point) {

  1761.         if (s->sample_rate_index != 8) {

  1762.             ptr = g->sb_hybrid + 36;

  1763.         } else {

  1764.             ptr = g->sb_hybrid + 48;

  1765.         }

  1766.     } else {

  1767.         ptr = g->sb_hybrid;

  1768.     }

  1769. 

  1770.     for(i=g->short_start;i<13;i++) {

  1771.         len = band_size_short[s->sample_rate_index][i];

  1772.         ptr1 = ptr;

  1773.         for(k=0;k<3;k++) {

  1774.             dst = tmp + k;

  1775.             for(j=len;j>0;j--) {

  1776.                 *dst = *ptr++;

  1777.                 dst += 3;

  1778.             }

  1779.         }

  1780.         memcpy(ptr1, tmp, len * 3 * sizeof(int32_t));

  1781.     }

  1782. }

  1783. 

  1784. #define ISQRT2 FIXR(0.70710678118654752440)

  1785. 

  1786. static void compute_stereo(MPADecodeContext *s,

  1787.                            GranuleDef *g0, GranuleDef *g1)

  1788. {

  1789.     int i, j, k, l;

  1790.     int32_t v1, v2;

  1791.     int sf_max, tmp0, tmp1, sf, len, non_zero_found;

  1792.     int32_t (*is_tab)[16];

  1793.     int32_t *tab0, *tab1;

  1794.     int non_zero_found_short[3];

  1795. 

  1796.     /* intensity stereo */

  1797.     if (s->mode_ext & MODE_EXT_I_STEREO) {

  1798.         if (!s->lsf) {

  1799.             is_tab = is_table;

  1800.             sf_max = 7;

  1801.         } else {

  1802.             is_tab = is_table_lsf[g1->scalefac_compress & 1];

  1803.             sf_max = 16;

  1804.         }

  1805. 

  1806.         tab0 = g0->sb_hybrid + 576;

  1807.         tab1 = g1->sb_hybrid + 576;

  1808. 

  1809.         non_zero_found_short[0] = 0;

  1810.         non_zero_found_short[1] = 0;

  1811.         non_zero_found_short[2] = 0;

  1812.         k = (13 - g1->short_start) * 3 + g1->long_end - 3;

  1813.         for(i = 12;i >= g1->short_start;i--) {

  1814.             /* for last band, use previous scale factor */

  1815.             if (i != 11)

  1816.                 k -= 3;

  1817.             len = band_size_short[s->sample_rate_index][i];

  1818.             for(l=2;l>=0;l--) {

  1819.                 tab0 -= len;

  1820.                 tab1 -= len;

  1821.                 if (!non_zero_found_short[l]) {

  1822.                     /* test if non zero band. if so, stop doing i-stereo */

  1823.                     for(j=0;j<len;j++) {

  1824.                         if (tab1[j] != 0) {

  1825.                             non_zero_found_short[l] = 1;

  1826.                             goto found1;

  1827.                         }

  1828.                     }

  1829.                     sf = g1->scale_factors[k + l];

  1830.                     if (sf >= sf_max)

  1831.                         goto found1;

  1832. 

  1833.                     v1 = is_tab[0][sf];

  1834.                     v2 = is_tab[1][sf];

  1835.                     for(j=0;j<len;j++) {

  1836.                         tmp0 = tab0[j];

  1837.                         tab0[j] = MULL(tmp0, v1);

  1838.                         tab1[j] = MULL(tmp0, v2);

  1839.                     }

  1840.                 } else {

  1841.                 found1:

  1842.                     if (s->mode_ext & MODE_EXT_MS_STEREO) {

  1843.                         /* lower part of the spectrum : do ms stereo

  1844.                            if enabled */

  1845.                         for(j=0;j<len;j++) {

  1846.                             tmp0 = tab0[j];

  1847.                             tmp1 = tab1[j];

  1848.                             tab0[j] = MULL(tmp0 + tmp1, ISQRT2);

  1849.                             tab1[j] = MULL(tmp0 - tmp1, ISQRT2);

  1850.                         }

  1851.                     }

  1852.                 }

  1853.             }

  1854.         }

  1855. 

  1856.         non_zero_found = non_zero_found_short[0] |

  1857.             non_zero_found_short[1] |

  1858.             non_zero_found_short[2];

  1859. 

  1860.         for(i = g1->long_end - 1;i >= 0;i--) {

  1861.             len = band_size_long[s->sample_rate_index][i];

  1862.             tab0 -= len;

  1863.             tab1 -= len;

  1864.             /* test if non zero band. if so, stop doing i-stereo */

  1865.             if (!non_zero_found) {

  1866.                 for(j=0;j<len;j++) {

  1867.                     if (tab1[j] != 0) {

  1868.                         non_zero_found = 1;

  1869.                         goto found2;

  1870.                     }

  1871.                 }

  1872.                 /* for last band, use previous scale factor */

  1873.                 k = (i == 21) ? 20 : i;

  1874.                 sf = g1->scale_factors[k];

  1875.                 if (sf >= sf_max)

  1876.                     goto found2;

  1877.                 v1 = is_tab[0][sf];

  1878.                 v2 = is_tab[1][sf];

  1879.                 for(j=0;j<len;j++) {

  1880.                     tmp0 = tab0[j];

  1881.                     tab0[j] = MULL(tmp0, v1);

  1882.                     tab1[j] = MULL(tmp0, v2);

  1883.                 }

  1884.             } else {

  1885.             found2:

  1886.                 if (s->mode_ext & MODE_EXT_MS_STEREO) {

  1887.                     /* lower part of the spectrum : do ms stereo

  1888.                        if enabled */

  1889.                     for(j=0;j<len;j++) {

  1890.                         tmp0 = tab0[j];

  1891.                         tmp1 = tab1[j];

  1892.                         tab0[j] = MULL(tmp0 + tmp1, ISQRT2);

  1893.                         tab1[j] = MULL(tmp0 - tmp1, ISQRT2);

  1894.                     }

  1895.                 }

  1896.             }

  1897.         }

  1898.     } else if (s->mode_ext & MODE_EXT_MS_STEREO) {

  1899.         /* ms stereo ONLY */

  1900.         /* NOTE: the 1/sqrt(2) normalization factor is included in the

  1901.            global gain */

  1902.         tab0 = g0->sb_hybrid;

  1903.         tab1 = g1->sb_hybrid;

  1904.         for(i=0;i<576;i++) {

  1905.             tmp0 = tab0[i];

  1906.             tmp1 = tab1[i];

  1907.             tab0[i] = tmp0 + tmp1;

  1908.             tab1[i] = tmp0 - tmp1;

  1909.         }

  1910.     }

  1911. }

  1912. 

  1913. static void compute_antialias_integer(MPADecodeContext *s,

  1914.                               GranuleDef *g)

  1915. {

  1916.     int32_t *ptr, *csa;

  1917.     int n, i;

  1918. 

  1919.     /* we antialias only "long" bands */

  1920.     if (g->block_type == 2) {

  1921.         if (!g->switch_point)

  1922.             return;

  1923.         /* XXX: check this for 8000Hz case */

  1924.         n = 1;

  1925.     } else {

  1926.         n = SBLIMIT - 1;

  1927.     }

  1928. 

  1929.     ptr = g->sb_hybrid + 18;

  1930.     for(i = n;i > 0;i--) {

  1931.         int tmp0, tmp1, tmp2;

  1932.         csa = &csa_table[0][0];

  1933. #define INT_AA(j) \

  1934.             tmp0 = ptr[-1-j];\

  1935.             tmp1 = ptr[   j];\

  1936.             tmp2= MULH(tmp0 + tmp1, csa[0+4*j]);\

  1937.             ptr[-1-j] = 4*(tmp2 - MULH(tmp1, csa[2+4*j]));\

  1938.             ptr[   j] = 4*(tmp2 + MULH(tmp0, csa[3+4*j]));

  1939. 

  1940.         INT_AA(0)

  1941.         INT_AA(1)

  1942.         INT_AA(2)

  1943.         INT_AA(3)

  1944.         INT_AA(4)

  1945.         INT_AA(5)

  1946.         INT_AA(6)

  1947.         INT_AA(7)

  1948. 

  1949.         ptr += 18;

  1950.     }

  1951. }

  1952. 

  1953. static void compute_antialias_float(MPADecodeContext *s,

  1954.                               GranuleDef *g)

  1955. {

  1956.     int32_t *ptr;

  1957.     int n, i;

  1958. 

  1959.     /* we antialias only "long" bands */

  1960.     if (g->block_type == 2) {

  1961.         if (!g->switch_point)

  1962.             return;

  1963.         /* XXX: check this for 8000Hz case */

  1964.         n = 1;

  1965.     } else {

  1966.         n = SBLIMIT - 1;

  1967.     }

  1968. 

  1969.     ptr = g->sb_hybrid + 18;

  1970.     for(i = n;i > 0;i--) {

  1971.         float tmp0, tmp1;

  1972.         float *csa = &csa_table_float[0][0];

  1973. #define FLOAT_AA(j)\

  1974.         tmp0= ptr[-1-j];\

  1975.         tmp1= ptr[   j];\

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

  1977.         ptr[   j] = lrintf(tmp0 * csa[1+4*j] + tmp1 * csa[0+4*j]);

  1978. 

  1979.         FLOAT_AA(0)

  1980.         FLOAT_AA(1)

  1981.         FLOAT_AA(2)

  1982.         FLOAT_AA(3)

  1983.         FLOAT_AA(4)

  1984.         FLOAT_AA(5)

  1985.         FLOAT_AA(6)

  1986.         FLOAT_AA(7)

  1987. 

  1988.         ptr += 18;

  1989.     }

  1990. }

  1991. 

  1992. static void compute_imdct(MPADecodeContext *s,

  1993.                           GranuleDef *g,

  1994.                           int32_t *sb_samples,

  1995.                           int32_t *mdct_buf)

  1996. {

  1997.     int32_t *ptr, *win, *win1, *buf, *out_ptr, *ptr1;

  1998.     int32_t out2[12];

  1999.     int i, j, mdct_long_end, v, sblimit;

  2000. 

  2001.     /* find last non zero block */

  2002.     ptr = g->sb_hybrid + 576;

  2003.     ptr1 = g->sb_hybrid + 2 * 18;

  2004.     while (ptr >= ptr1) {

  2005.         ptr -= 6;

  2006.         v = ptr[0] | ptr[1] | ptr[2] | ptr[3] | ptr[4] | ptr[5];

  2007.         if (v != 0)

  2008.             break;

  2009.     }

  2010.     sblimit = ((ptr - g->sb_hybrid) / 18) + 1;

  2011. 

  2012.     if (g->block_type == 2) {

  2013.         /* XXX: check for 8000 Hz */

  2014.         if (g->switch_point)

  2015.             mdct_long_end = 2;

  2016.         else

  2017.             mdct_long_end = 0;

  2018.     } else {

  2019.         mdct_long_end = sblimit;

  2020.     }

  2021. 

  2022.     buf = mdct_buf;

  2023.     ptr = g->sb_hybrid;

  2024.     for(j=0;j<mdct_long_end;j++) {

  2025.         /* apply window & overlap with previous buffer */

  2026.         out_ptr = sb_samples + j;

  2027.         /* select window */

  2028.         if (g->switch_point && j < 2)

  2029.             win1 = mdct_win[0];

  2030.         else

  2031.             win1 = mdct_win[g->block_type];

  2032.         /* select frequency inversion */

  2033.         win = win1 + ((4 * 36) & -(j & 1));

  2034.         imdct36(out_ptr, buf, ptr, win);

  2035.         out_ptr += 18*SBLIMIT;

  2036.         ptr += 18;

  2037.         buf += 18;

  2038.     }

  2039.     for(j=mdct_long_end;j<sblimit;j++) {

  2040.         /* select frequency inversion */

  2041.         win = mdct_win[2] + ((4 * 36) & -(j & 1));

  2042.         out_ptr = sb_samples + j;

  2043. 

  2044.         for(i=0; i<6; i++){

  2045.             *out_ptr = buf[i];

  2046.             out_ptr += SBLIMIT;

  2047.         }

  2048.         imdct12(out2, ptr + 0);

  2049.         for(i=0;i<6;i++) {

  2050.             *out_ptr = MULH(out2[i], win[i]) + buf[i + 6*1];

  2051.             buf[i + 6*2] = MULH(out2[i + 6], win[i + 6]);

  2052.             out_ptr += SBLIMIT;

  2053.         }

  2054.         imdct12(out2, ptr + 1);

  2055.         for(i=0;i<6;i++) {

  2056.             *out_ptr = MULH(out2[i], win[i]) + buf[i + 6*2];

  2057.             buf[i + 6*0] = MULH(out2[i + 6], win[i + 6]);

  2058.             out_ptr += SBLIMIT;

  2059.         }

  2060.         imdct12(out2, ptr + 2);

  2061.         for(i=0;i<6;i++) {

  2062.             buf[i + 6*0] = MULH(out2[i], win[i]) + buf[i + 6*0];

  2063.             buf[i + 6*1] = MULH(out2[i + 6], win[i + 6]);

  2064.             buf[i + 6*2] = 0;

  2065.         }

  2066.         ptr += 18;

  2067.         buf += 18;

  2068.     }

  2069.     /* zero bands */

  2070.     for(j=sblimit;j<SBLIMIT;j++) {

  2071.         /* overlap */

  2072.         out_ptr = sb_samples + j;

  2073.         for(i=0;i<18;i++) {

  2074.             *out_ptr = buf[i];

  2075.             buf[i] = 0;

  2076.             out_ptr += SBLIMIT;

  2077.         }

  2078.         buf += 18;

  2079.     }

  2080. }

  2081. 

  2082. #if defined(DEBUG)

  2083. void sample_dump(int fnum, int32_t *tab, int n)

  2084. {

  2085.     static FILE *files[16], *f;

  2086.     char buf[512];

  2087.     int i;

  2088.     int32_t v;

  2089. 

  2090.     f = files[fnum];

  2091.     if (!f) {

  2092.         snprintf(buf, sizeof(buf), "/tmp/out%d.%s.pcm",

  2093.                 fnum,

  2094. #ifdef USE_HIGHPRECISION

  2095.                 "hp"

  2096. #else

  2097.                 "lp"

  2098. #endif

  2099.                 );

  2100.         f = fopen(buf, "w");

  2101.         if (!f)

  2102.             return;

  2103.         files[fnum] = f;

  2104.     }

  2105. 

  2106.     if (fnum == 0) {

  2107.         static int pos = 0;

  2108.         av_log(NULL, AV_LOG_DEBUG, "pos=%d\n", pos);

  2109.         for(i=0;i<n;i++) {

  2110.             av_log(NULL, AV_LOG_DEBUG, " %0.4f", (double)tab[i] / FRAC_ONE);

  2111.             if ((i % 18) == 17)

  2112.                 av_log(NULL, AV_LOG_DEBUG, "\n");

  2113.         }

  2114.         pos += n;

  2115.     }

  2116.     for(i=0;i<n;i++) {

  2117.         /* normalize to 23 frac bits */

  2118.         v = tab[i] << (23 - FRAC_BITS);

  2119.         fwrite(&v, 1, sizeof(int32_t), f);

  2120.     }

  2121. }

  2122. #endif

  2123. 

  2124. 

  2125. /* main layer3 decoding function */

  2126. static int mp_decode_layer3(MPADecodeContext *s)

  2127. {

  2128.     int nb_granules, main_data_begin, private_bits;

  2129.     int gr, ch, blocksplit_flag, i, j, k, n, bits_pos, bits_left;

  2130.     GranuleDef granules[2][2], *g;

  2131.     int16_t exponents[576];

  2132. 

  2133.     /* read side info */

  2134.     if (s->lsf) {

  2135.         main_data_begin = get_bits(&s->gb, 8);

  2136.         if (s->nb_channels == 2)

  2137.             private_bits = get_bits(&s->gb, 2);

  2138.         else

  2139.             private_bits = get_bits(&s->gb, 1);

  2140.         nb_granules = 1;

  2141.     } else {

  2142.         main_data_begin = get_bits(&s->gb, 9);

  2143.         if (s->nb_channels == 2)

  2144.             private_bits = get_bits(&s->gb, 3);

  2145.         else

  2146.             private_bits = get_bits(&s->gb, 5);

  2147.         nb_granules = 2;

  2148.         for(ch=0;ch<s->nb_channels;ch++) {

  2149.             granules[ch][0].scfsi = 0; /* all scale factors are transmitted */

  2150.             granules[ch][1].scfsi = get_bits(&s->gb, 4);

  2151.         }

  2152.     }

  2153. 

  2154.     for(gr=0;gr<nb_granules;gr++) {

  2155.         for(ch=0;ch<s->nb_channels;ch++) {

  2156.             dprintf("gr=%d ch=%d: side_info\n", gr, ch);

  2157.             g = &granules[ch][gr];

  2158.             g->part2_3_length = get_bits(&s->gb, 12);

  2159.             g->big_values = get_bits(&s->gb, 9);

  2160.             g->global_gain = get_bits(&s->gb, 8);

  2161.             /* if MS stereo only is selected, we precompute the

  2162.                1/sqrt(2) renormalization factor */

  2163.             if ((s->mode_ext & (MODE_EXT_MS_STEREO | MODE_EXT_I_STEREO)) ==

  2164.                 MODE_EXT_MS_STEREO)

  2165.                 g->global_gain -= 2;

  2166.             if (s->lsf)

  2167.                 g->scalefac_compress = get_bits(&s->gb, 9);

  2168.             else

  2169.                 g->scalefac_compress = get_bits(&s->gb, 4);

  2170.             blocksplit_flag = get_bits(&s->gb, 1);

  2171.             if (blocksplit_flag) {

  2172.                 g->block_type = get_bits(&s->gb, 2);

  2173.                 if (g->block_type == 0)

  2174.                     return -1;

  2175.                 g->switch_point = get_bits(&s->gb, 1);

  2176.                 for(i=0;i<2;i++)

  2177.                     g->table_select[i] = get_bits(&s->gb, 5);

  2178.                 for(i=0;i<3;i++)

  2179.                     g->subblock_gain[i] = get_bits(&s->gb, 3);

  2180.                 /* compute huffman coded region sizes */

  2181.                 if (g->block_type == 2)

  2182.                     g->region_size[0] = (36 / 2);

  2183.                 else {

  2184.                     if (s->sample_rate_index <= 2)

  2185.                         g->region_size[0] = (36 / 2);

  2186.                     else if (s->sample_rate_index != 8)

  2187.                         g->region_size[0] = (54 / 2);

  2188.                     else

  2189.                         g->region_size[0] = (108 / 2);

  2190.                 }

  2191.                 g->region_size[1] = (576 / 2);

  2192.             } else {

  2193.                 int region_address1, region_address2, l;

  2194.                 g->block_type = 0;

  2195.                 g->switch_point = 0;

  2196.                 for(i=0;i<3;i++)

  2197.                     g->table_select[i] = get_bits(&s->gb, 5);

  2198.                 /* compute huffman coded region sizes */

  2199.                 region_address1 = get_bits(&s->gb, 4);

  2200.                 region_address2 = get_bits(&s->gb, 3);

  2201.                 dprintf("region1=%d region2=%d\n",

  2202.                         region_address1, region_address2);

  2203.                 g->region_size[0] =

  2204.                     band_index_long[s->sample_rate_index][region_address1 + 1] >> 1;

  2205.                 l = region_address1 + region_address2 + 2;

  2206.                 /* should not overflow */

  2207.                 if (l > 22)

  2208.                     l = 22;

  2209.                 g->region_size[1] =

  2210.                     band_index_long[s->sample_rate_index][l] >> 1;

  2211.             }

  2212.             /* convert region offsets to region sizes and truncate

  2213.                size to big_values */

  2214.             g->region_size[2] = (576 / 2);

  2215.             j = 0;

  2216.             for(i=0;i<3;i++) {

  2217.                 k = g->region_size[i];

  2218.                 if (k > g->big_values)

  2219.                     k = g->big_values;

  2220.                 g->region_size[i] = k - j;

  2221.                 j = k;

  2222.             }

  2223. 

  2224.             /* compute band indexes */

  2225.             if (g->block_type == 2) {

  2226.                 if (g->switch_point) {

  2227.                     /* if switched mode, we handle the 36 first samples as

  2228.                        long blocks.  For 8000Hz, we handle the 48 first

  2229.                        exponents as long blocks (XXX: check this!) */

  2230.                     if (s->sample_rate_index <= 2)

  2231.                         g->long_end = 8;

  2232.                     else if (s->sample_rate_index != 8)

  2233.                         g->long_end = 6;

  2234.                     else

  2235.                         g->long_end = 4; /* 8000 Hz */

  2236. 

  2237.                     if (s->sample_rate_index != 8)

  2238.                         g->short_start = 3;

  2239.                     else

  2240.                         g->short_start = 2;

  2241.                 } else {

  2242.                     g->long_end = 0;

  2243.                     g->short_start = 0;

  2244.                 }

  2245.             } else {

  2246.                 g->short_start = 13;

  2247.                 g->long_end = 22;

  2248.             }

  2249. 

  2250.             g->preflag = 0;

  2251.             if (!s->lsf)

  2252.                 g->preflag = get_bits(&s->gb, 1);

  2253.             g->scalefac_scale = get_bits(&s->gb, 1);

  2254.             g->count1table_select = get_bits(&s->gb, 1);

  2255.             dprintf("block_type=%d switch_point=%d\n",

  2256.                     g->block_type, g->switch_point);

  2257.         }

  2258.     }

  2259. 

  2260.   if (!s->adu_mode) {

  2261.     /* now we get bits from the main_data_begin offset */

  2262.     dprintf("seekback: %d\n", main_data_begin);

  2263.     seek_to_maindata(s, main_data_begin);

  2264.   }

  2265. 

  2266.     for(gr=0;gr<nb_granules;gr++) {

  2267.         for(ch=0;ch<s->nb_channels;ch++) {

  2268.             g = &granules[ch][gr];

  2269. 

  2270.             bits_pos = get_bits_count(&s->gb);

  2271. 

  2272.             if (!s->lsf) {

  2273.                 uint8_t *sc;

  2274.                 int slen, slen1, slen2;

  2275. 

  2276.                 /* MPEG1 scale factors */

  2277.                 slen1 = slen_table[0][g->scalefac_compress];

  2278.                 slen2 = slen_table[1][g->scalefac_compress];

  2279.                 dprintf("slen1=%d slen2=%d\n", slen1, slen2);

  2280.                 if (g->block_type == 2) {

  2281.                     n = g->switch_point ? 17 : 18;

  2282.                     j = 0;

  2283.                     for(i=0;i<n;i++)

  2284.                         g->scale_factors[j++] = get_bitsz(&s->gb, slen1);

  2285.                     for(i=0;i<18;i++)

  2286.                         g->scale_factors[j++] = get_bitsz(&s->gb, slen2);

  2287.                     for(i=0;i<3;i++)

  2288.                         g->scale_factors[j++] = 0;

  2289.                 } else {

  2290.                     sc = granules[ch][0].scale_factors;

  2291.                     j = 0;

  2292.                     for(k=0;k<4;k++) {

  2293.                         n = (k == 0 ? 6 : 5);

  2294.                         if ((g->scfsi & (0x8 >> k)) == 0) {

  2295.                             slen = (k < 2) ? slen1 : slen2;

  2296.                             for(i=0;i<n;i++)

  2297.                                 g->scale_factors[j++] = get_bitsz(&s->gb, slen);

  2298.                         } else {

  2299.                             /* simply copy from last granule */

  2300.                             for(i=0;i<n;i++) {

  2301.                                 g->scale_factors[j] = sc[j];

  2302.                                 j++;

  2303.                             }

  2304.                         }

  2305.                     }

  2306.                     g->scale_factors[j++] = 0;

  2307.                 }

  2308. #if defined(DEBUG)

  2309.                 {

  2310.                     dprintf("scfsi=%x gr=%d ch=%d scale_factors:\n",

  2311.                            g->scfsi, gr, ch);

  2312.                     for(i=0;i<j;i++)

  2313.                         dprintf(" %d", g->scale_factors[i]);

  2314.                     dprintf("\n");

  2315.                 }

  2316. #endif

  2317.             } else {

  2318.                 int tindex, tindex2, slen[4], sl, sf;

  2319. 

  2320.                 /* LSF scale factors */

  2321.                 if (g->block_type == 2) {

  2322.                     tindex = g->switch_point ? 2 : 1;

  2323.                 } else {

  2324.                     tindex = 0;

  2325.                 }

  2326.                 sf = g->scalefac_compress;

  2327.                 if ((s->mode_ext & MODE_EXT_I_STEREO) && ch == 1) {

  2328.                     /* intensity stereo case */

  2329.                     sf >>= 1;

  2330.                     if (sf < 180) {

  2331.                         lsf_sf_expand(slen, sf, 6, 6, 0);

  2332.                         tindex2 = 3;

  2333.                     } else if (sf < 244) {

  2334.                         lsf_sf_expand(slen, sf - 180, 4, 4, 0);

  2335.                         tindex2 = 4;

  2336.                     } else {

  2337.                         lsf_sf_expand(slen, sf - 244, 3, 0, 0);

  2338.                         tindex2 = 5;

  2339.                     }

  2340.                 } else {

  2341.                     /* normal case */

  2342.                     if (sf < 400) {

  2343.                         lsf_sf_expand(slen, sf, 5, 4, 4);

  2344.                         tindex2 = 0;

  2345.                     } else if (sf < 500) {

  2346.                         lsf_sf_expand(slen, sf - 400, 5, 4, 0);

  2347.                         tindex2 = 1;

  2348.                     } else {

  2349.                         lsf_sf_expand(slen, sf - 500, 3, 0, 0);

  2350.                         tindex2 = 2;

  2351.                         g->preflag = 1;

  2352.                     }

  2353.                 }

  2354. 

  2355.                 j = 0;

  2356.                 for(k=0;k<4;k++) {

  2357.                     n = lsf_nsf_table[tindex2][tindex][k];

  2358.                     sl = slen[k];

  2359.                     for(i=0;i<n;i++)

  2360.                         g->scale_factors[j++] = get_bitsz(&s->gb, sl);

  2361.                 }

  2362.                 /* XXX: should compute exact size */

  2363.                 for(;j<40;j++)

  2364.                     g->scale_factors[j] = 0;

  2365. #if defined(DEBUG)

  2366.                 {

  2367.                     dprintf("gr=%d ch=%d scale_factors:\n",

  2368.                            gr, ch);

  2369.                     for(i=0;i<40;i++)

  2370.                         dprintf(" %d", g->scale_factors[i]);

  2371.                     dprintf("\n");

  2372.                 }

  2373. #endif

  2374.             }

  2375. 

  2376.             exponents_from_scale_factors(s, g, exponents);

  2377. 

  2378.             /* read Huffman coded residue */

  2379.             if (huffman_decode(s, g, exponents,

  2380.                                bits_pos + g->part2_3_length) < 0)

  2381.                 return -1;

  2382. #if defined(DEBUG)

  2383.             sample_dump(0, g->sb_hybrid, 576);

  2384. #endif

  2385. 

  2386.             /* skip extension bits */

  2387.             bits_left = g->part2_3_length - (get_bits_count(&s->gb) - bits_pos);

  2388.             if (bits_left < 0) {

  2389.                 dprintf("bits_left=%d\n", bits_left);

  2390.                 return -1;

  2391.             }

  2392.             while (bits_left >= 16) {

  2393.                 skip_bits(&s->gb, 16);

  2394.                 bits_left -= 16;

  2395.             }

  2396.             if (bits_left > 0)

  2397.                 skip_bits(&s->gb, bits_left);

  2398.         } /* ch */

  2399. 

  2400.         if (s->nb_channels == 2)

  2401.             compute_stereo(s, &granules[0][gr], &granules[1][gr]);

  2402. 

  2403.         for(ch=0;ch<s->nb_channels;ch++) {

  2404.             g = &granules[ch][gr];

  2405. 

  2406.             reorder_block(s, g);

  2407. #if defined(DEBUG)

  2408.             sample_dump(0, g->sb_hybrid, 576);

  2409. #endif

  2410.             s->compute_antialias(s, g);

  2411. #if defined(DEBUG)

  2412.             sample_dump(1, g->sb_hybrid, 576);

  2413. #endif

  2414.             compute_imdct(s, g, &s->sb_samples[ch][18 * gr][0], s->mdct_buf[ch]);

  2415. #if defined(DEBUG)

  2416.             sample_dump(2, &s->sb_samples[ch][18 * gr][0], 576);

  2417. #endif

  2418.         }

  2419.     } /* gr */

  2420.     return nb_granules * 18;

  2421. }

  2422. 

  2423. static int mp_decode_frame(MPADecodeContext *s,

  2424.                            OUT_INT *samples)

  2425. {

  2426.     int i, nb_frames, ch;

  2427.     OUT_INT *samples_ptr;

  2428. 

  2429.     init_get_bits(&s->gb, s->inbuf + HEADER_SIZE,

  2430.                   (s->inbuf_ptr - s->inbuf - HEADER_SIZE)*8);

  2431. 

  2432.     /* skip error protection field */

  2433.     if (s->error_protection)

  2434.         get_bits(&s->gb, 16);

  2435. 

  2436.     dprintf("frame %d:\n", s->frame_count);

  2437.     switch(s->layer) {

  2438.     case 1:

  2439.         nb_frames = mp_decode_layer1(s);

  2440.         break;

  2441.     case 2:

  2442.         nb_frames = mp_decode_layer2(s);

  2443.         break;

  2444.     case 3:

  2445.     default:

  2446.         nb_frames = mp_decode_layer3(s);

  2447.         break;

  2448.     }

  2449. #if defined(DEBUG)

  2450.     for(i=0;i<nb_frames;i++) {

  2451.         for(ch=0;ch<s->nb_channels;ch++) {

  2452.             int j;

  2453.             dprintf("%d-%d:", i, ch);

  2454.             for(j=0;j<SBLIMIT;j++)

  2455.                 dprintf(" %0.6f", (double)s->sb_samples[ch][i][j] / FRAC_ONE);

  2456.             dprintf("\n");

  2457.         }

  2458.     }

  2459. #endif

  2460.     /* apply the synthesis filter */

  2461.     for(ch=0;ch<s->nb_channels;ch++) {

  2462.         samples_ptr = samples + ch;

  2463.         for(i=0;i<nb_frames;i++) {

  2464.             ff_mpa_synth_filter(s->synth_buf[ch], &(s->synth_buf_offset[ch]),

  2465.                          window, &s->dither_state,

  2466.                          samples_ptr, s->nb_channels,

  2467.                          s->sb_samples[ch][i]);

  2468.             samples_ptr += 32 * s->nb_channels;

  2469.         }

  2470.     }

  2471. #ifdef DEBUG

  2472.     s->frame_count++;

  2473. #endif

  2474.     return nb_frames * 32 * sizeof(OUT_INT) * s->nb_channels;

  2475. }

  2476. 

  2477. static int decode_frame(AVCodecContext * avctx,

  2478.                         void *data, int *data_size,

  2479.                         uint8_t * buf, int buf_size)

  2480. {

  2481.     MPADecodeContext *s = avctx->priv_data;

  2482.     uint32_t header;

  2483.     uint8_t *buf_ptr;

  2484.     int len, out_size;

  2485.     OUT_INT *out_samples = data;

  2486. 

  2487.     buf_ptr = buf;

  2488.     while (buf_size > 0) {

  2489.         len = s->inbuf_ptr - s->inbuf;

  2490.         if (s->frame_size == 0) {

  2491.             /* special case for next header for first frame in free

  2492.                format case (XXX: find a simpler method) */

  2493.             if (s->free_format_next_header != 0) {

  2494.                 s->inbuf[0] = s->free_format_next_header >> 24;

  2495.                 s->inbuf[1] = s->free_format_next_header >> 16;

  2496.                 s->inbuf[2] = s->free_format_next_header >> 8;

  2497.                 s->inbuf[3] = s->free_format_next_header;

  2498.                 s->inbuf_ptr = s->inbuf + 4;

  2499.                 s->free_format_next_header = 0;

  2500.                 goto got_header;

  2501.             }

  2502.             /* no header seen : find one. We need at least HEADER_SIZE

  2503.                bytes to parse it */

  2504.             len = HEADER_SIZE - len;

  2505.             if (len > buf_size)

  2506.                 len = buf_size;

  2507.             if (len > 0) {

  2508.                 memcpy(s->inbuf_ptr, buf_ptr, len);

  2509.                 buf_ptr += len;

  2510.                 buf_size -= len;

  2511.                 s->inbuf_ptr += len;

  2512.             }

  2513.             if ((s->inbuf_ptr - s->inbuf) >= HEADER_SIZE) {

  2514.             got_header:

  2515.                 header = (s->inbuf[0] << 24) | (s->inbuf[1] << 16) |

  2516.                     (s->inbuf[2] << 8) | s->inbuf[3];

  2517. 

  2518.                 if (ff_mpa_check_header(header) < 0) {

  2519.                     /* no sync found : move by one byte (inefficient, but simple!) */

  2520.                     memmove(s->inbuf, s->inbuf + 1, s->inbuf_ptr - s->inbuf - 1);

  2521.                     s->inbuf_ptr--;

  2522.                     dprintf("skip %x\n", header);

  2523.                     /* reset free format frame size to give a chance

  2524.                        to get a new bitrate */

  2525.                     s->free_format_frame_size = 0;

  2526.                 } else {

  2527.                     if (decode_header(s, header) == 1) {

  2528.                         /* free format: prepare to compute frame size */

  2529.                         s->frame_size = -1;

  2530.                     }

  2531.                     /* update codec info */

  2532.                     avctx->sample_rate = s->sample_rate;

  2533.                     avctx->channels = s->nb_channels;

  2534.                     avctx->bit_rate = s->bit_rate;

  2535.                     avctx->sub_id = s->layer;

  2536.                     switch(s->layer) {

  2537.                     case 1:

  2538.                         avctx->frame_size = 384;

  2539.                         break;

  2540.                     case 2:

  2541.                         avctx->frame_size = 1152;

  2542.                         break;

  2543.                     case 3:

  2544.                         if (s->lsf)

  2545.                             avctx->frame_size = 576;

  2546.                         else

  2547.                             avctx->frame_size = 1152;

  2548.                         break;

  2549.                     }

  2550.                 }

  2551.             }

  2552.         } else if (s->frame_size == -1) {

  2553.             /* free format : find next sync to compute frame size */

  2554.             len = MPA_MAX_CODED_FRAME_SIZE - len;

  2555.             if (len > buf_size)

  2556.                 len = buf_size;

  2557.             if (len == 0) {

  2558.                 /* frame too long: resync */

  2559.                 s->frame_size = 0;

  2560.                 memmove(s->inbuf, s->inbuf + 1, s->inbuf_ptr - s->inbuf - 1);

  2561.                 s->inbuf_ptr--;

  2562.             } else {

  2563.                 uint8_t *p, *pend;

  2564.                 uint32_t header1;

  2565.                 int padding;

  2566. 

  2567.                 memcpy(s->inbuf_ptr, buf_ptr, len);

  2568.                 /* check for header */

  2569.                 p = s->inbuf_ptr - 3;

  2570.                 pend = s->inbuf_ptr + len - 4;

  2571.                 while (p <= pend) {

  2572.                     header = (p[0] << 24) | (p[1] << 16) |

  2573.                         (p[2] << 8) | p[3];

  2574.                     header1 = (s->inbuf[0] << 24) | (s->inbuf[1] << 16) |

  2575.                         (s->inbuf[2] << 8) | s->inbuf[3];

  2576.                     /* check with high probability that we have a

  2577.                        valid header */

  2578.                     if ((header & SAME_HEADER_MASK) ==

  2579.                         (header1 & SAME_HEADER_MASK)) {

  2580.                         /* header found: update pointers */

  2581.                         len = (p + 4) - s->inbuf_ptr;

  2582.                         buf_ptr += len;

  2583.                         buf_size -= len;

  2584.                         s->inbuf_ptr = p;

  2585.                         /* compute frame size */

  2586.                         s->free_format_next_header = header;

  2587.                         s->free_format_frame_size = s->inbuf_ptr - s->inbuf;

  2588.                         padding = (header1 >> 9) & 1;

  2589.                         if (s->layer == 1)

  2590.                             s->free_format_frame_size -= padding * 4;

  2591.                         else

  2592.                             s->free_format_frame_size -= padding;

  2593.                         dprintf("free frame size=%d padding=%d\n",

  2594.                                 s->free_format_frame_size, padding);

  2595.                         decode_header(s, header1);

  2596.                         goto next_data;

  2597.                     }

  2598.                     p++;

  2599.                 }

  2600.                 /* not found: simply increase pointers */

  2601.                 buf_ptr += len;

  2602.                 s->inbuf_ptr += len;

  2603.                 buf_size -= len;

  2604.             }

  2605.         } else if (len < s->frame_size) {

  2606.             if (s->frame_size > MPA_MAX_CODED_FRAME_SIZE)

  2607.                 s->frame_size = MPA_MAX_CODED_FRAME_SIZE;

  2608.             len = s->frame_size - len;

  2609.             if (len > buf_size)

  2610.                 len = buf_size;

  2611.             memcpy(s->inbuf_ptr, buf_ptr, len);

  2612.             buf_ptr += len;

  2613.             s->inbuf_ptr += len;

  2614.             buf_size -= len;

  2615.         }

  2616.     next_data:

  2617.         if (s->frame_size > 0 &&

  2618.             (s->inbuf_ptr - s->inbuf) >= s->frame_size) {

  2619.             if (avctx->parse_only) {

  2620.                 /* simply return the frame data */

  2621.                 *(uint8_t **)data = s->inbuf;

  2622.                 out_size = s->inbuf_ptr - s->inbuf;

  2623.             } else {

  2624.                 out_size = mp_decode_frame(s, out_samples);

  2625.             }

  2626.             s->inbuf_ptr = s->inbuf;

  2627.             s->frame_size = 0;

  2628.             if(out_size>=0)

  2629.                 *data_size = out_size;

  2630.             else

  2631.                 av_log(avctx, AV_LOG_DEBUG, "Error while decoding mpeg audio frame\n"); //FIXME return -1 / but also return the number of bytes consumed

  2632.             break;

  2633.         }

  2634.     }

  2635.     return buf_ptr - buf;

  2636. }

  2637. 

  2638. 

  2639. static int decode_frame_adu(AVCodecContext * avctx,

  2640.                         void *data, int *data_size,

  2641.                         uint8_t * buf, int buf_size)

  2642. {

  2643.     MPADecodeContext *s = avctx->priv_data;

  2644.     uint32_t header;

  2645.     int len, out_size;

  2646.     OUT_INT *out_samples = data;

  2647. 

  2648.     len = buf_size;

  2649. 

  2650.     // Discard too short frames

  2651.     if (buf_size < HEADER_SIZE) {

  2652.         *data_size = 0;

  2653.         return buf_size;

  2654.     }

  2655. 

  2656. 

  2657.     if (len > MPA_MAX_CODED_FRAME_SIZE)

  2658.         len = MPA_MAX_CODED_FRAME_SIZE;

  2659. 

  2660.     memcpy(s->inbuf, buf, len);

  2661.     s->inbuf_ptr = s->inbuf + len;

  2662. 

  2663.     // Get header and restore sync word

  2664.     header = (s->inbuf[0] << 24) | (s->inbuf[1] << 16) |

  2665.               (s->inbuf[2] << 8) | s->inbuf[3] | 0xffe00000;

  2666. 

  2667.     if (ff_mpa_check_header(header) < 0) { // Bad header, discard frame

  2668.         *data_size = 0;

  2669.         return buf_size;

  2670.     }

  2671. 

  2672.     decode_header(s, header);

  2673.     /* update codec info */

  2674.     avctx->sample_rate = s->sample_rate;

  2675.     avctx->channels = s->nb_channels;

  2676.     avctx->bit_rate = s->bit_rate;

  2677.     avctx->sub_id = s->layer;

  2678. 

  2679.     avctx->frame_size=s->frame_size = len;

  2680. 

  2681.     if (avctx->parse_only) {

  2682.         /* simply return the frame data */

  2683.         *(uint8_t **)data = s->inbuf;

  2684.         out_size = s->inbuf_ptr - s->inbuf;

  2685.     } else {

  2686.         out_size = mp_decode_frame(s, out_samples);

  2687.     }

  2688. 

  2689.     *data_size = out_size;

  2690.     return buf_size;

  2691. }

  2692. 

  2693. 

  2694. /* Next 3 arrays are indexed by channel config number (passed via codecdata) */

  2695. static int mp3Frames[16] = {0,1,1,2,3,3,4,5,2};   /* number of mp3 decoder instances */

  2696. static int mp3Channels[16] = {0,1,2,3,4,5,6,8,4}; /* total output channels */

  2697. /* offsets into output buffer, assume output order is FL FR BL BR C LFE */

  2698. static int chan_offset[9][5] = {

  2699.     {0},

  2700.     {0},            // C

  2701.     {0},            // FLR

  2702.     {2,0},          // C FLR

  2703.     {2,0,3},        // C FLR BS

  2704.     {4,0,2},        // C FLR BLRS

  2705.     {4,0,2,5},      // C FLR BLRS LFE

  2706.     {4,0,2,6,5},    // C FLR BLRS BLR LFE

  2707.     {0,2}           // FLR BLRS

  2708. };

  2709. 

  2710. 

  2711. static int decode_init_mp3on4(AVCodecContext * avctx)

  2712. {

  2713.     MP3On4DecodeContext *s = avctx->priv_data;

  2714.     int i;

  2715. 

  2716.     if ((avctx->extradata_size < 2) || (avctx->extradata == NULL)) {

  2717.         av_log(avctx, AV_LOG_ERROR, "Codec extradata missing or too short.\n");

  2718.         return -1;

  2719.     }

  2720. 

  2721.     s->chan_cfg = (((unsigned char *)avctx->extradata)[1] >> 3) & 0x0f;

  2722.     s->frames = mp3Frames[s->chan_cfg];

  2723.     if(!s->frames) {

  2724.         av_log(avctx, AV_LOG_ERROR, "Invalid channel config number.\n");

  2725.         return -1;

  2726.     }

  2727.     avctx->channels = mp3Channels[s->chan_cfg];

  2728. 

  2729.     /* Init the first mp3 decoder in standard way, so that all tables get builded

  2730.      * We replace avctx->priv_data with the context of the first decoder so that

  2731.      * decode_init() does not have to be changed.

  2732.      * Other decoders will be inited here copying data from the first context

  2733.      */

  2734.     // Allocate zeroed memory for the first decoder context

  2735.     s->mp3decctx[0] = av_mallocz(sizeof(MPADecodeContext));

  2736.     // Put decoder context in place to make init_decode() happy

  2737.     avctx->priv_data = s->mp3decctx[0];

  2738.     decode_init(avctx);

  2739.     // Restore mp3on4 context pointer

  2740.     avctx->priv_data = s;

  2741.     s->mp3decctx[0]->adu_mode = 1; // Set adu mode

  2742. 

  2743.     /* Create a separate codec/context for each frame (first is already ok).

  2744.      * Each frame is 1 or 2 channels - up to 5 frames allowed

  2745.      */

  2746.     for (i = 1; i < s->frames; i++) {

  2747.         s->mp3decctx[i] = av_mallocz(sizeof(MPADecodeContext));

  2748.         s->mp3decctx[i]->compute_antialias = s->mp3decctx[0]->compute_antialias;

  2749.         s->mp3decctx[i]->inbuf = &s->mp3decctx[i]->inbuf1[0][BACKSTEP_SIZE];

  2750.         s->mp3decctx[i]->inbuf_ptr = s->mp3decctx[i]->inbuf;

  2751.         s->mp3decctx[i]->adu_mode = 1;

  2752.     }

  2753. 

  2754.     return 0;

  2755. }

  2756. 

  2757. 

  2758. static int decode_close_mp3on4(AVCodecContext * avctx)

  2759. {

  2760.     MP3On4DecodeContext *s = avctx->priv_data;

  2761.     int i;

  2762. 

  2763.     for (i = 0; i < s->frames; i++)

  2764.         if (s->mp3decctx[i])

  2765.             av_free(s->mp3decctx[i]);

  2766. 

  2767.     return 0;

  2768. }

  2769. 

  2770. 

  2771. static int decode_frame_mp3on4(AVCodecContext * avctx,

  2772.                         void *data, int *data_size,

  2773.                         uint8_t * buf, int buf_size)

  2774. {

  2775.     MP3On4DecodeContext *s = avctx->priv_data;

  2776.     MPADecodeContext *m;

  2777.     int len, out_size = 0;

  2778.     uint32_t header;

  2779.     OUT_INT *out_samples = data;

  2780.     OUT_INT decoded_buf[MPA_FRAME_SIZE * MPA_MAX_CHANNELS];

  2781.     OUT_INT *outptr, *bp;

  2782.     int fsize;

  2783.     unsigned char *start2 = buf, *start;

  2784.     int fr, i, j, n;

  2785.     int off = avctx->channels;

  2786.     int *coff = chan_offset[s->chan_cfg];

  2787. 

  2788.     len = buf_size;

  2789. 

  2790.     // Discard too short frames

  2791.     if (buf_size < HEADER_SIZE) {

  2792.         *data_size = 0;

  2793.         return buf_size;

  2794.     }

  2795. 

  2796.     // If only one decoder interleave is not needed

  2797.     outptr = s->frames == 1 ? out_samples : decoded_buf;

  2798. 

  2799.     for (fr = 0; fr < s->frames; fr++) {

  2800.         start = start2;

  2801.         fsize = (start[0] << 4) | (start[1] >> 4);

  2802.         start2 += fsize;

  2803.         if (fsize > len)

  2804.             fsize = len;

  2805.         len -= fsize;

  2806.         if (fsize > MPA_MAX_CODED_FRAME_SIZE)

  2807.             fsize = MPA_MAX_CODED_FRAME_SIZE;

  2808.         m = s->mp3decctx[fr];

  2809.         assert (m != NULL);

  2810.         /* copy original to new */

  2811.         m->inbuf_ptr = m->inbuf + fsize;

  2812.         memcpy(m->inbuf, start, fsize);

  2813. 

  2814.         // Get header

  2815.         header = (m->inbuf[0] << 24) | (m->inbuf[1] << 16) |

  2816.                   (m->inbuf[2] << 8) | m->inbuf[3] | 0xfff00000;

  2817. 

  2818.         if (ff_mpa_check_header(header) < 0) { // Bad header, discard block

  2819.             *data_size = 0;

  2820.             return buf_size;

  2821.         }

  2822. 

  2823.         decode_header(m, header);

  2824.         mp_decode_frame(m, decoded_buf);

  2825. 

  2826.         n = MPA_FRAME_SIZE * m->nb_channels;

  2827.         out_size += n * sizeof(OUT_INT);

  2828.         if(s->frames > 1) {

  2829.             /* interleave output data */

  2830.             bp = out_samples + coff[fr];

  2831.             if(m->nb_channels == 1) {

  2832.                 for(j = 0; j < n; j++) {

  2833.                     *bp = decoded_buf[j];

  2834.                     bp += off;

  2835.                 }

  2836.             } else {

  2837.                 for(j = 0; j < n; j++) {

  2838.                     bp[0] = decoded_buf[j++];

  2839.                     bp[1] = decoded_buf[j];

  2840.                     bp += off;

  2841.                 }

  2842.             }

  2843.         }

  2844.     }

  2845. 

  2846.     /* update codec info */

  2847.     avctx->sample_rate = s->mp3decctx[0]->sample_rate;

  2848.     avctx->frame_size= buf_size;

  2849.     avctx->bit_rate = 0;

  2850.     for (i = 0; i < s->frames; i++)

  2851.         avctx->bit_rate += s->mp3decctx[i]->bit_rate;

  2852. 

  2853.     *data_size = out_size;

  2854.     return buf_size;

  2855. }

  2856. 

  2857. 

  2858. AVCodec mp2_decoder =

  2859. {

  2860.     "mp2",

  2861.     CODEC_TYPE_AUDIO,

  2862.     CODEC_ID_MP2,

  2863.     sizeof(MPADecodeContext),

  2864.     decode_init,

  2865.     NULL,

  2866.     NULL,

  2867.     decode_frame,

  2868.     CODEC_CAP_PARSE_ONLY,

  2869. };

  2870. 

  2871. AVCodec mp3_decoder =

  2872. {

  2873.     "mp3",

  2874.     CODEC_TYPE_AUDIO,

  2875.     CODEC_ID_MP3,

  2876.     sizeof(MPADecodeContext),

  2877.     decode_init,

  2878.     NULL,

  2879.     NULL,

  2880.     decode_frame,

  2881.     CODEC_CAP_PARSE_ONLY,

  2882. };

  2883. 

  2884. AVCodec mp3adu_decoder =

  2885. {

  2886.     "mp3adu",

  2887.     CODEC_TYPE_AUDIO,

  2888.     CODEC_ID_MP3ADU,

  2889.     sizeof(MPADecodeContext),

  2890.     decode_init,

  2891.     NULL,

  2892.     NULL,

  2893.     decode_frame_adu,

  2894.     CODEC_CAP_PARSE_ONLY,

  2895. };

  2896. 

  2897. AVCodec mp3on4_decoder =

  2898. {

  2899.     "mp3on4",

  2900.     CODEC_TYPE_AUDIO,

  2901.     CODEC_ID_MP3ON4,

  2902.     sizeof(MP3On4DecodeContext),

  2903.     decode_init_mp3on4,

  2904.     NULL,

  2905.     decode_close_mp3on4,

  2906.     decode_frame_mp3on4,

  2907.     0

  2908. };