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FFmpeg/libavcodec/mpegaudiodec.c

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  1. /*

  2.  * MPEG Audio decoder

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

  4.  *

  5.  * This file is part of Libav.

  6.  *

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

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

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

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

  11.  *

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

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

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

  15.  * Lesser General Public License for more details.

  16.  *

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

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

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

  20.  */

  21. 

  22. /**

  23.  * @file

  24.  * MPEG Audio decoder.

  25.  */

  26. 

  27. #include "libavutil/audioconvert.h"

  28. #include "avcodec.h"

  29. #include "get_bits.h"

  30. #include "mathops.h"

  31. #include "mpegaudiodsp.h"

  32. 

  33. /*

  34.  * TODO:

  35.  *  - test lsf / mpeg25 extensively.

  36.  */

  37. 

  38. #include "mpegaudio.h"

  39. #include "mpegaudiodecheader.h"

  40. 

  41. #define BACKSTEP_SIZE 512

  42. #define EXTRABYTES 24

  43. 

  44. /* layer 3 "granule" */

  45. typedef struct GranuleDef {

  46.     uint8_t scfsi;

  47.     int part2_3_length;

  48.     int big_values;

  49.     int global_gain;

  50.     int scalefac_compress;

  51.     uint8_t block_type;

  52.     uint8_t switch_point;

  53.     int table_select[3];

  54.     int subblock_gain[3];

  55.     uint8_t scalefac_scale;

  56.     uint8_t count1table_select;

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

  58.     int preflag;

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

  60.     uint8_t scale_factors[40];

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

  62. } GranuleDef;

  63. 

  64. typedef struct MPADecodeContext {

  65.     MPA_DECODE_HEADER

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

  67.     int last_buf_size;

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

  69.     uint32_t free_format_next_header;

  70.     GetBitContext gb;

  71.     GetBitContext in_gb;

  72.     DECLARE_ALIGNED(32, MPA_INT, synth_buf)[MPA_MAX_CHANNELS][512 * 2];

  73.     int synth_buf_offset[MPA_MAX_CHANNELS];

  74.     DECLARE_ALIGNED(32, INTFLOAT, sb_samples)[MPA_MAX_CHANNELS][36][SBLIMIT];

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

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

  77. #ifdef DEBUG

  78.     int frame_count;

  79. #endif

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

  81.     int dither_state;

  82.     int error_recognition;

  83.     AVCodecContext* avctx;

  84.     MPADSPContext mpadsp;

  85. } MPADecodeContext;

  86. 

  87. #if CONFIG_FLOAT

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

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

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

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

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

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

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

  95. #   define OUT_FMT AV_SAMPLE_FMT_FLT

  96. #else

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

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

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

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

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

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

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

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

  105. #   define OUT_FMT AV_SAMPLE_FMT_S16

  106. #endif

  107. 

  108. /****************/

  109. 

  110. #define HEADER_SIZE 4

  111. 

  112. #include "mpegaudiodata.h"

  113. #include "mpegaudiodectab.h"

  114. 

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

  116. static VLC huff_vlc[16];

  117. static VLC_TYPE huff_vlc_tables[

  118.   0+128+128+128+130+128+154+166+

  119.   142+204+190+170+542+460+662+414

  120.   ][2];

  121. static const int huff_vlc_tables_sizes[16] = {

  122.   0, 128, 128, 128, 130, 128, 154, 166,

  123.   142, 204, 190, 170, 542, 460, 662, 414

  124. };

  125. static VLC huff_quad_vlc[2];

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

  127. static const int huff_quad_vlc_tables_sizes[2] = {

  128.   128, 16

  129. };

  130. /* computed from band_size_long */

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

  132. #include "mpegaudio_tablegen.h"

  133. /* intensity stereo coef table */

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

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

  136. static INTFLOAT csa_table[8][4];

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

  138. 

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

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

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

  142. 

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

  144.     division_tab3, division_tab5, NULL, division_tab9

  145. };

  146. 

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

  148. static uint16_t scale_factor_modshift[64];

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

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

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

  152. 

  153. #define SCALE_GEN(v) \

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

  155. 

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

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

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

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

  160. };

  161. 

  162. /**

  163.  * Convert region offsets to region sizes and truncate

  164.  * size to big_values.

  165.  */

  166. static void ff_region_offset2size(GranuleDef *g){

  167.     int i, k, j=0;

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

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

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

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

  172.         j = k;

  173.     }

  174. }

  175. 

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

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

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

  179.     else {

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

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

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

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

  184.         else

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

  186.     }

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

  188. }

  189. 

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

  191.     int l;

  192.     g->region_size[0] =

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

  194.     /* should not overflow */

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

  196.     g->region_size[1] =

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

  198. }

  199. 

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

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

  202.         if (g->switch_point) {

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

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

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

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

  207.                 g->long_end = 8;

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

  209.                 g->long_end = 6;

  210.             else

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

  212. 

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

  214.         } else {

  215.             g->long_end = 0;

  216.             g->short_start = 0;

  217.         }

  218.     } else {

  219.         g->short_start = 13;

  220.         g->long_end = 22;

  221.     }

  222. }

  223. 

  224. /* layer 1 unscaling */

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

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

  227. {

  228.     int shift, mod;

  229.     int64_t val;

  230. 

  231.     shift = scale_factor_modshift[scale_factor];

  232.     mod = shift & 3;

  233.     shift >>= 2;

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

  235.     shift += n;

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

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

  238. }

  239. 

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

  241. {

  242.     int shift, mod, val;

  243. 

  244.     shift = scale_factor_modshift[scale_factor];

  245.     mod = shift & 3;

  246.     shift >>= 2;

  247. 

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

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

  250.     if (shift > 0)

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

  252.     return val;

  253. }

  254. 

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

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

  257. {

  258.     unsigned int m;

  259.     int e;

  260. 

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

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

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

  264.     assert(e>=1);

  265.     if (e > 31)

  266.         return 0;

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

  268. 

  269.     return m;

  270. }

  271. 

  272. static av_cold int decode_init(AVCodecContext * avctx)

  273. {

  274.     MPADecodeContext *s = avctx->priv_data;

  275.     static int init=0;

  276.     int i, j, k;

  277. 

  278.     s->avctx = avctx;

  279. 

  280.     ff_mpadsp_init(&s->mpadsp);

  281. 

  282.     avctx->sample_fmt= OUT_FMT;

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

  284. 

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

  286.         int offset;

  287. 

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

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

  290.             int shift, mod;

  291.             /* 1.0 (i = 3) is normalized to 2 ^ FRAC_BITS */

  292.             shift = (i / 3);

  293.             mod = i % 3;

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

  295.         }

  296. 

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

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

  299.             int n, norm;

  300.             n = i + 2;

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

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

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

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

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

  306.                     i, norm,

  307.                     scale_factor_mult[i][0],

  308.                     scale_factor_mult[i][1],

  309.                     scale_factor_mult[i][2]);

  310.         }

  311. 

  312.         RENAME(ff_mpa_synth_init)(RENAME(ff_mpa_synth_window));

  313. 

  314.         /* huffman decode tables */

  315.         offset = 0;

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

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

  318.             int xsize, x, y;

  319.             uint8_t  tmp_bits [512];

  320.             uint16_t tmp_codes[512];

  321. 

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

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

  324. 

  325.             xsize = h->xsize;

  326. 

  327.             j = 0;

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

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

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

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

  332.                 }

  333.             }

  334. 

  335.             /* XXX: fail test */

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

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

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

  339.                      tmp_bits, 1, 1, tmp_codes, 2, 2,

  340.                      INIT_VLC_USE_NEW_STATIC);

  341.             offset += huff_vlc_tables_sizes[i];

  342.         }

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

  344. 

  345.         offset = 0;

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

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

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

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

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

  351.                      INIT_VLC_USE_NEW_STATIC);

  352.             offset += huff_quad_vlc_tables_sizes[i];

  353.         }

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

  355. 

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

  357.             k = 0;

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

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

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

  361.             }

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

  363.         }

  364. 

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

  366. 

  367.         mpegaudio_tableinit();

  368. 

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

  370.             if (ff_mpa_quant_bits[i] < 0)

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

  372.                     int val1, val2, val3, steps;

  373.                     int val = j;

  374.                     steps  = ff_mpa_quant_steps[i];

  375.                     val1 = val % steps;

  376.                     val /= steps;

  377.                     val2 = val % steps;

  378.                     val3 = val / steps;

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

  380.                 }

  381. 

  382. 

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

  384.             float f;

  385.             INTFLOAT v;

  386.             if (i != 6) {

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

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

  389.             } else {

  390.                 v = FIXR(1.0);

  391.             }

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

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

  394.         }

  395.         /* invalid values */

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

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

  398. 

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

  400.             double f;

  401.             int e, k;

  402. 

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

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

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

  406.                 k = i & 1;

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

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

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

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

  411.             }

  412.         }

  413. 

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

  415.             float ci, cs, ca;

  416.             ci = ci_table[i];

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

  418.             ca = cs * ci;

  419. #if !CONFIG_FLOAT

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

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

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

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

  424. #else

  425.             csa_table[i][0] = cs;

  426.             csa_table[i][1] = ca;

  427.             csa_table[i][2] = ca + cs;

  428.             csa_table[i][3] = ca - cs;

  429. #endif

  430.         }

  431. 

  432.         /* compute mdct windows */

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

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

  435.                 double d;

  436. 

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

  438.                     continue;

  439. 

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

  441.                 if(j==1){

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

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

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

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

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

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

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

  449.                 }

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

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

  452. 

  453.                 if(j==2)

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

  455.                 else

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

  457.             }

  458.         }

  459. 

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

  461.            the sign of the right window coefs */

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

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

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

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

  466.             }

  467.         }

  468. 

  469.         init = 1;

  470.     }

  471. 

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

  473.         s->adu_mode = 1;

  474.     return 0;

  475. }

  476. 

  477. #define C3 FIXHR(0.86602540378443864676/2)

  478. 

  479. /* 0.5 / cos(pi*(2*i+1)/36) */

  480. static const INTFLOAT icos36[9] = {

  481.     FIXR(0.50190991877167369479),

  482.     FIXR(0.51763809020504152469), //0

  483.     FIXR(0.55168895948124587824),

  484.     FIXR(0.61038729438072803416),

  485.     FIXR(0.70710678118654752439), //1

  486.     FIXR(0.87172339781054900991),

  487.     FIXR(1.18310079157624925896),

  488.     FIXR(1.93185165257813657349), //2

  489.     FIXR(5.73685662283492756461),

  490. };

  491. 

  492. /* 0.5 / cos(pi*(2*i+1)/36) */

  493. static const INTFLOAT icos36h[9] = {

  494.     FIXHR(0.50190991877167369479/2),

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

  496.     FIXHR(0.55168895948124587824/2),

  497.     FIXHR(0.61038729438072803416/2),

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

  499.     FIXHR(0.87172339781054900991/2),

  500.     FIXHR(1.18310079157624925896/4),

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

  502. //    FIXHR(5.73685662283492756461),

  503. };

  504. 

  505. /* 12 points IMDCT. We compute it "by hand" by factorizing obvious

  506.    cases. */

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

  508. {

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

  510. 

  511.     in0= in[0*3];

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

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

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

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

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

  517.     in5 += in3;

  518.     in3 += in1;

  519. 

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

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

  522. 

  523.     t1 = in0 - in4;

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

  525. 

  526.     out[ 7]=

  527.     out[10]= t1 + t2;

  528.     out[ 1]=

  529.     out[ 4]= t1 - t2;

  530. 

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

  532.     in4 = in0 + in2;

  533.     in5 += 2*in1;

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

  535.     out[ 8]=

  536.     out[ 9]= in4 + in1;

  537.     out[ 2]=

  538.     out[ 3]= in4 - in1;

  539. 

  540.     in0 -= in2;

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

  542.     out[ 0]=

  543.     out[ 5]= in0 - in5;

  544.     out[ 6]=

  545.     out[11]= in0 + in5;

  546. }

  547. 

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

  549. #define C1 FIXHR(0.98480775301220805936/2)

  550. #define C2 FIXHR(0.93969262078590838405/2)

  551. #define C3 FIXHR(0.86602540378443864676/2)

  552. #define C4 FIXHR(0.76604444311897803520/2)

  553. #define C5 FIXHR(0.64278760968653932632/2)

  554. #define C6 FIXHR(0.5/2)

  555. #define C7 FIXHR(0.34202014332566873304/2)

  556. #define C8 FIXHR(0.17364817766693034885/2)

  557. 

  558. 

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

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

  561. {

  562.     int i, j;

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

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

  565. 

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

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

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

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

  570. 

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

  572.         tmp1 = tmp + j;

  573.         in1 = in + j;

  574. 

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

  576. 

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

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

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

  580.         tmp1[16] = t1 + t2;

  581. 

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

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

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

  585. 

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

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

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

  589. 

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

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

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

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

  594. 

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

  596. 

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

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

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

  600.     }

  601. 

  602.     i = 0;

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

  604.         t0 = tmp[i];

  605.         t1 = tmp[i + 2];

  606.         s0 = t1 + t0;

  607.         s2 = t1 - t0;

  608. 

  609.         t2 = tmp[i + 1];

  610.         t3 = tmp[i + 3];

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

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

  613. 

  614.         t0 = s0 + s1;

  615.         t1 = s0 - s1;

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

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

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

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

  620. 

  621.         t0 = s2 + s3;

  622.         t1 = s2 - s3;

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

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

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

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

  627.         i += 4;

  628.     }

  629. 

  630.     s0 = tmp[16];

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

  632.     t0 = s0 + s1;

  633.     t1 = s0 - s1;

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

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

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

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

  638. }

  639. 

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

  641. static int mp_decode_layer1(MPADecodeContext *s)

  642. {

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

  644.     uint8_t allocation[MPA_MAX_CHANNELS][SBLIMIT];

  645.     uint8_t scale_factors[MPA_MAX_CHANNELS][SBLIMIT];

  646. 

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

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

  649.     else

  650.         bound = SBLIMIT;

  651. 

  652.     /* allocation bits */

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

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

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

  656.         }

  657.     }

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

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

  660.     }

  661. 

  662.     /* scale factors */

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

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

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

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

  667.         }

  668.     }

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

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

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

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

  673.         }

  674.     }

  675. 

  676.     /* compute samples */

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

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

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

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

  681.                 if (n) {

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

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

  684.                 } else {

  685.                     v = 0;

  686.                 }

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

  688.             }

  689.         }

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

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

  692.             if (n) {

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

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

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

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

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

  698.             } else {

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

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

  701.             }

  702.         }

  703.     }

  704.     return 12;

  705. }

  706. 

  707. static int mp_decode_layer2(MPADecodeContext *s)

  708. {

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

  710.     const unsigned char *alloc_table;

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

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

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

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

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

  716. 

  717.     /* select decoding table */

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

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

  720.     sblimit = ff_mpa_sblimit_table[table];

  721.     alloc_table = ff_mpa_alloc_tables[table];

  722. 

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

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

  725.     else

  726.         bound = sblimit;

  727. 

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

  729. 

  730.     /* sanity check */

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

  732. 

  733.     /* parse bit allocation */

  734.     j = 0;

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

  736.         bit_alloc_bits = alloc_table[j];

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

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

  739.         }

  740.         j += 1 << bit_alloc_bits;

  741.     }

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

  743.         bit_alloc_bits = alloc_table[j];

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

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

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

  747.         j += 1 << bit_alloc_bits;

  748.     }

  749. 

  750.     /* scale codes */

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

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

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

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

  755.         }

  756.     }

  757. 

  758.     /* scale factors */

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

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

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

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

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

  764.                 default:

  765.                 case 0:

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

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

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

  769.                     break;

  770.                 case 2:

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

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

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

  774.                     break;

  775.                 case 1:

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

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

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

  779.                     break;

  780.                 case 3:

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

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

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

  784.                     break;

  785.                 }

  786.             }

  787.         }

  788.     }

  789. 

  790.     /* samples */

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

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

  793.             j = 0;

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

  795.                 bit_alloc_bits = alloc_table[j];

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

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

  798.                     if (b) {

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

  800.                         qindex = alloc_table[j+b];

  801.                         bits = ff_mpa_quant_bits[qindex];

  802.                         if (bits < 0) {

  803.                             int v2;

  804.                             /* 3 values at the same time */

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

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

  807.                             steps  = ff_mpa_quant_steps[qindex];

  808. 

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

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

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

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

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

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

  815.                         } else {

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

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

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

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

  820.                             }

  821.                         }

  822.                     } else {

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

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

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

  826.                     }

  827.                 }

  828.                 /* next subband in alloc table */

  829.                 j += 1 << bit_alloc_bits;

  830.             }

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

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

  833.                 bit_alloc_bits = alloc_table[j];

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

  835.                 if (b) {

  836.                     int mant, scale0, scale1;

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

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

  839.                     qindex = alloc_table[j+b];

  840.                     bits = ff_mpa_quant_bits[qindex];

  841.                     if (bits < 0) {

  842.                         /* 3 values at the same time */

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

  844.                         steps = ff_mpa_quant_steps[qindex];

  845.                         mant = v % steps;

  846.                         v = v / steps;

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

  848.                             l2_unscale_group(steps, mant, scale0);

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

  850.                             l2_unscale_group(steps, mant, scale1);

  851.                         mant = v % steps;

  852.                         v = v / steps;

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

  854.                             l2_unscale_group(steps, mant, scale0);

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

  856.                             l2_unscale_group(steps, mant, scale1);

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

  858.                             l2_unscale_group(steps, v, scale0);

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

  860.                             l2_unscale_group(steps, v, scale1);

  861.                     } else {

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

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

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

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

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

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

  868.                         }

  869.                     }

  870.                 } else {

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

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

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

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

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

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

  877.                 }

  878.                 /* next subband in alloc table */

  879.                 j += 1 << bit_alloc_bits;

  880.             }

  881.             /* fill remaining samples to zero */

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

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

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

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

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

  887.                 }

  888.             }

  889.         }

  890.     }

  891.     return 3 * 12;

  892. }

  893. 

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

  895.     if(n==3){\

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

  897.         dst= sf - 3*m;\

  898.         sf=m;\

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

  900.         dst= sf&3;\

  901.         sf>>=2;\

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

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

  904.         dst= sf - 5*m;\

  905.         sf=m;\

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

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

  908.         dst= sf - 6*m;\

  909.         sf=m;\

  910.     }else{\

  911.         dst=0;\

  912.     }

  913. 

  914. static av_always_inline void lsf_sf_expand(int *slen,

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

  916. {

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

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

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

  920.     slen[0] = sf;

  921. }

  922. 

  923. static void exponents_from_scale_factors(MPADecodeContext *s,

  924.                                          GranuleDef *g,

  925.                                          int16_t *exponents)

  926. {

  927.     const uint8_t *bstab, *pretab;

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

  929.     int16_t *exp_ptr;

  930. 

  931.     exp_ptr = exponents;

  932.     gain = g->global_gain - 210;

  933.     shift = g->scalefac_scale + 1;

  934. 

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

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

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

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

  939.         len = bstab[i];

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

  941.             *exp_ptr++ = v0;

  942.     }

  943. 

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

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

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

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

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

  949.         k = g->long_end;

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

  951.             len = bstab[i];

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

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

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

  955.                 *exp_ptr++ = v0;

  956.             }

  957.         }

  958.     }

  959. }

  960. 

  961. /* handle n = 0 too */

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

  963. {

  964.     if (n == 0)

  965.         return 0;

  966.     else

  967.         return get_bits(s, n);

  968. }

  969. 

  970. 

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

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

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

  974.         s->in_gb.buffer=NULL;

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

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

  977.         *end_pos2=

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

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

  980.     }

  981. }

  982. 

  983. /* Following is a optimized code for

  984.             INTFLOAT v = *src

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

  986.                 v = -v;

  987.             *dst = v;

  988. */

  989. #if CONFIG_FLOAT

  990. #define READ_FLIP_SIGN(dst,src)\

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

  992.             AV_WN32A(dst, v);

  993. #else

  994. #define READ_FLIP_SIGN(dst,src)\

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

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

  997. #endif

  998. 

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

  1000.                           int16_t *exponents, int end_pos2)

  1001. {

  1002.     int s_index;

  1003.     int i;

  1004.     int last_pos, bits_left;

  1005.     VLC *vlc;

  1006.     int end_pos= FFMIN(end_pos2, s->gb.size_in_bits);

  1007. 

  1008.     /* low frequencies (called big values) */

  1009.     s_index = 0;

  1010.     for(i=0;i<3;i++) {

  1011.         int j, k, l, linbits;

  1012.         j = g->region_size[i];

  1013.         if (j == 0)

  1014.             continue;

  1015.         /* select vlc table */

  1016.         k = g->table_select[i];

  1017.         l = mpa_huff_data[k][0];

  1018.         linbits = mpa_huff_data[k][1];

  1019.         vlc = &huff_vlc[l];

  1020. 

  1021.         if(!l){

  1022.             memset(&g->sb_hybrid[s_index], 0, sizeof(*g->sb_hybrid)*2*j);

  1023.             s_index += 2*j;

  1024.             continue;

  1025.         }

  1026. 

  1027.         /* read huffcode and compute each couple */

  1028.         for(;j>0;j--) {

  1029.             int exponent, x, y;

  1030.             int v;

  1031.             int pos= get_bits_count(&s->gb);

  1032. 

  1033.             if (pos >= end_pos){

  1034. //                av_log(NULL, AV_LOG_ERROR, "pos: %d %d %d %d\n", pos, end_pos, end_pos2, s_index);

  1035.                 switch_buffer(s, &pos, &end_pos, &end_pos2);

  1036. //                av_log(NULL, AV_LOG_ERROR, "new pos: %d %d\n", pos, end_pos);

  1037.                 if(pos >= end_pos)

  1038.                     break;

  1039.             }

  1040.             y = get_vlc2(&s->gb, vlc->table, 7, 3);

  1041. 

  1042.             if(!y){

  1043.                 g->sb_hybrid[s_index  ] =

  1044.                 g->sb_hybrid[s_index+1] = 0;

  1045.                 s_index += 2;

  1046.                 continue;

  1047.             }

  1048. 

  1049.             exponent= exponents[s_index];

  1050. 

  1051.             av_dlog(s->avctx, "region=%d n=%d x=%d y=%d exp=%d\n",

  1052.                     i, g->region_size[i] - j, x, y, exponent);

  1053.             if(y&16){

  1054.                 x = y >> 5;

  1055.                 y = y & 0x0f;

  1056.                 if (x < 15){

  1057.                     READ_FLIP_SIGN(g->sb_hybrid+s_index, RENAME(expval_table)[ exponent ]+x)

  1058.                 }else{

  1059.                     x += get_bitsz(&s->gb, linbits);

  1060.                     v = l3_unscale(x, exponent);

  1061.                     if (get_bits1(&s->gb))

  1062.                         v = -v;

  1063.                     g->sb_hybrid[s_index] = v;

  1064.                 }

  1065.                 if (y < 15){

  1066.                     READ_FLIP_SIGN(g->sb_hybrid+s_index+1, RENAME(expval_table)[ exponent ]+y)

  1067.                 }else{

  1068.                     y += get_bitsz(&s->gb, linbits);

  1069.                     v = l3_unscale(y, exponent);

  1070.                     if (get_bits1(&s->gb))

  1071.                         v = -v;

  1072.                     g->sb_hybrid[s_index+1] = v;

  1073.                 }

  1074.             }else{

  1075.                 x = y >> 5;

  1076.                 y = y & 0x0f;

  1077.                 x += y;

  1078.                 if (x < 15){

  1079.                     READ_FLIP_SIGN(g->sb_hybrid+s_index+!!y, RENAME(expval_table)[ exponent ]+x)

  1080.                 }else{

  1081.                     x += get_bitsz(&s->gb, linbits);

  1082.                     v = l3_unscale(x, exponent);

  1083.                     if (get_bits1(&s->gb))

  1084.                         v = -v;

  1085.                     g->sb_hybrid[s_index+!!y] = v;

  1086.                 }

  1087.                 g->sb_hybrid[s_index+ !y] = 0;

  1088.             }

  1089.             s_index+=2;

  1090.         }

  1091.     }

  1092. 

  1093.     /* high frequencies */

  1094.     vlc = &huff_quad_vlc[g->count1table_select];

  1095.     last_pos=0;

  1096.     while (s_index <= 572) {

  1097.         int pos, code;

  1098.         pos = get_bits_count(&s->gb);

  1099.         if (pos >= end_pos) {

  1100.             if (pos > end_pos2 && last_pos){

  1101.                 /* some encoders generate an incorrect size for this

  1102.                    part. We must go back into the data */

  1103.                 s_index -= 4;

  1104.                 skip_bits_long(&s->gb, last_pos - pos);

  1105.                 av_log(s->avctx, AV_LOG_INFO, "overread, skip %d enddists: %d %d\n", last_pos - pos, end_pos-pos, end_pos2-pos);

  1106.                 if(s->error_recognition >= FF_ER_COMPLIANT)

  1107.                     s_index=0;

  1108.                 break;

  1109.             }

  1110. //                av_log(NULL, AV_LOG_ERROR, "pos2: %d %d %d %d\n", pos, end_pos, end_pos2, s_index);

  1111.             switch_buffer(s, &pos, &end_pos, &end_pos2);

  1112. //                av_log(NULL, AV_LOG_ERROR, "new pos2: %d %d %d\n", pos, end_pos, s_index);

  1113.             if(pos >= end_pos)

  1114.                 break;

  1115.         }

  1116.         last_pos= pos;

  1117. 

  1118.         code = get_vlc2(&s->gb, vlc->table, vlc->bits, 1);

  1119.         av_dlog(s->avctx, "t=%d code=%d\n", g->count1table_select, code);

  1120.         g->sb_hybrid[s_index+0]=

  1121.         g->sb_hybrid[s_index+1]=

  1122.         g->sb_hybrid[s_index+2]=

  1123.         g->sb_hybrid[s_index+3]= 0;

  1124.         while(code){

  1125.             static const int idxtab[16]={3,3,2,2,1,1,1,1,0,0,0,0,0,0,0,0};

  1126.             int v;

  1127.             int pos= s_index+idxtab[code];

  1128.             code ^= 8>>idxtab[code];

  1129.             READ_FLIP_SIGN(g->sb_hybrid+pos, RENAME(exp_table)+exponents[pos])

  1130.         }

  1131.         s_index+=4;

  1132.     }

  1133.     /* skip extension bits */

  1134.     bits_left = end_pos2 - get_bits_count(&s->gb);

  1135. //av_log(NULL, AV_LOG_ERROR, "left:%d buf:%p\n", bits_left, s->in_gb.buffer);

  1136.     if (bits_left < 0 && s->error_recognition >= FF_ER_COMPLIANT) {

  1137.         av_log(s->avctx, AV_LOG_ERROR, "bits_left=%d\n", bits_left);

  1138.         s_index=0;

  1139.     }else if(bits_left > 0 && s->error_recognition >= FF_ER_AGGRESSIVE){

  1140.         av_log(s->avctx, AV_LOG_ERROR, "bits_left=%d\n", bits_left);

  1141.         s_index=0;

  1142.     }

  1143.     memset(&g->sb_hybrid[s_index], 0, sizeof(*g->sb_hybrid)*(576 - s_index));

  1144.     skip_bits_long(&s->gb, bits_left);

  1145. 

  1146.     i= get_bits_count(&s->gb);

  1147.     switch_buffer(s, &i, &end_pos, &end_pos2);

  1148. 

  1149.     return 0;

  1150. }

  1151. 

  1152. /* Reorder short blocks from bitstream order to interleaved order. It

  1153.    would be faster to do it in parsing, but the code would be far more

  1154.    complicated */

  1155. static void reorder_block(MPADecodeContext *s, GranuleDef *g)

  1156. {

  1157.     int i, j, len;

  1158.     INTFLOAT *ptr, *dst, *ptr1;

  1159.     INTFLOAT tmp[576];

  1160. 

  1161.     if (g->block_type != 2)

  1162.         return;

  1163. 

  1164.     if (g->switch_point) {

  1165.         if (s->sample_rate_index != 8) {

  1166.             ptr = g->sb_hybrid + 36;

  1167.         } else {

  1168.             ptr = g->sb_hybrid + 48;

  1169.         }

  1170.     } else {

  1171.         ptr = g->sb_hybrid;

  1172.     }

  1173. 

  1174.     for(i=g->short_start;i<13;i++) {

  1175.         len = band_size_short[s->sample_rate_index][i];

  1176.         ptr1 = ptr;

  1177.         dst = tmp;

  1178.         for(j=len;j>0;j--) {

  1179.             *dst++ = ptr[0*len];

  1180.             *dst++ = ptr[1*len];

  1181.             *dst++ = ptr[2*len];

  1182.             ptr++;

  1183.         }

  1184.         ptr+=2*len;

  1185.         memcpy(ptr1, tmp, len * 3 * sizeof(*ptr1));

  1186.     }

  1187. }

  1188. 

  1189. #define ISQRT2 FIXR(0.70710678118654752440)

  1190. 

  1191. static void compute_stereo(MPADecodeContext *s,

  1192.                            GranuleDef *g0, GranuleDef *g1)

  1193. {

  1194.     int i, j, k, l;

  1195.     int sf_max, sf, len, non_zero_found;

  1196.     INTFLOAT (*is_tab)[16], *tab0, *tab1, tmp0, tmp1, v1, v2;

  1197.     int non_zero_found_short[3];

  1198. 

  1199.     /* intensity stereo */

  1200.     if (s->mode_ext & MODE_EXT_I_STEREO) {

  1201.         if (!s->lsf) {

  1202.             is_tab = is_table;

  1203.             sf_max = 7;

  1204.         } else {

  1205.             is_tab = is_table_lsf[g1->scalefac_compress & 1];

  1206.             sf_max = 16;

  1207.         }

  1208. 

  1209.         tab0 = g0->sb_hybrid + 576;

  1210.         tab1 = g1->sb_hybrid + 576;

  1211. 

  1212.         non_zero_found_short[0] = 0;

  1213.         non_zero_found_short[1] = 0;

  1214.         non_zero_found_short[2] = 0;

  1215.         k = (13 - g1->short_start) * 3 + g1->long_end - 3;

  1216.         for(i = 12;i >= g1->short_start;i--) {

  1217.             /* for last band, use previous scale factor */

  1218.             if (i != 11)

  1219.                 k -= 3;

  1220.             len = band_size_short[s->sample_rate_index][i];

  1221.             for(l=2;l>=0;l--) {

  1222.                 tab0 -= len;

  1223.                 tab1 -= len;

  1224.                 if (!non_zero_found_short[l]) {

  1225.                     /* test if non zero band. if so, stop doing i-stereo */

  1226.                     for(j=0;j<len;j++) {

  1227.                         if (tab1[j] != 0) {

  1228.                             non_zero_found_short[l] = 1;

  1229.                             goto found1;

  1230.                         }

  1231.                     }

  1232.                     sf = g1->scale_factors[k + l];

  1233.                     if (sf >= sf_max)

  1234.                         goto found1;

  1235. 

  1236.                     v1 = is_tab[0][sf];

  1237.                     v2 = is_tab[1][sf];

  1238.                     for(j=0;j<len;j++) {

  1239.                         tmp0 = tab0[j];

  1240.                         tab0[j] = MULLx(tmp0, v1, FRAC_BITS);

  1241.                         tab1[j] = MULLx(tmp0, v2, FRAC_BITS);

  1242.                     }

  1243.                 } else {

  1244.                 found1:

  1245.                     if (s->mode_ext & MODE_EXT_MS_STEREO) {

  1246.                         /* lower part of the spectrum : do ms stereo

  1247.                            if enabled */

  1248.                         for(j=0;j<len;j++) {

  1249.                             tmp0 = tab0[j];

  1250.                             tmp1 = tab1[j];

  1251.                             tab0[j] = MULLx(tmp0 + tmp1, ISQRT2, FRAC_BITS);

  1252.                             tab1[j] = MULLx(tmp0 - tmp1, ISQRT2, FRAC_BITS);

  1253.                         }

  1254.                     }

  1255.                 }

  1256.             }

  1257.         }

  1258. 

  1259.         non_zero_found = non_zero_found_short[0] |

  1260.             non_zero_found_short[1] |

  1261.             non_zero_found_short[2];

  1262. 

  1263.         for(i = g1->long_end - 1;i >= 0;i--) {

  1264.             len = band_size_long[s->sample_rate_index][i];

  1265.             tab0 -= len;

  1266.             tab1 -= len;

  1267.             /* test if non zero band. if so, stop doing i-stereo */

  1268.             if (!non_zero_found) {

  1269.                 for(j=0;j<len;j++) {

  1270.                     if (tab1[j] != 0) {

  1271.                         non_zero_found = 1;

  1272.                         goto found2;

  1273.                     }

  1274.                 }

  1275.                 /* for last band, use previous scale factor */

  1276.                 k = (i == 21) ? 20 : i;

  1277.                 sf = g1->scale_factors[k];

  1278.                 if (sf >= sf_max)

  1279.                     goto found2;

  1280.                 v1 = is_tab[0][sf];

  1281.                 v2 = is_tab[1][sf];

  1282.                 for(j=0;j<len;j++) {

  1283.                     tmp0 = tab0[j];

  1284.                     tab0[j] = MULLx(tmp0, v1, FRAC_BITS);

  1285.                     tab1[j] = MULLx(tmp0, v2, FRAC_BITS);

  1286.                 }

  1287.             } else {

  1288.             found2:

  1289.                 if (s->mode_ext & MODE_EXT_MS_STEREO) {

  1290.                     /* lower part of the spectrum : do ms stereo

  1291.                        if enabled */

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

  1293.                         tmp0 = tab0[j];

  1294.                         tmp1 = tab1[j];

  1295.                         tab0[j] = MULLx(tmp0 + tmp1, ISQRT2, FRAC_BITS);

  1296.                         tab1[j] = MULLx(tmp0 - tmp1, ISQRT2, FRAC_BITS);

  1297.                     }

  1298.                 }

  1299.             }

  1300.         }

  1301.     } else if (s->mode_ext & MODE_EXT_MS_STEREO) {

  1302.         /* ms stereo ONLY */

  1303.         /* NOTE: the 1/sqrt(2) normalization factor is included in the

  1304.            global gain */

  1305.         tab0 = g0->sb_hybrid;

  1306.         tab1 = g1->sb_hybrid;

  1307.         for(i=0;i<576;i++) {

  1308.             tmp0 = tab0[i];

  1309.             tmp1 = tab1[i];

  1310.             tab0[i] = tmp0 + tmp1;

  1311.             tab1[i] = tmp0 - tmp1;

  1312.         }

  1313.     }

  1314. }

  1315. 

  1316. #if CONFIG_FLOAT

  1317. #define AA(j) do {                                                      \

  1318.         float tmp0 = ptr[-1-j];                                         \

  1319.         float tmp1 = ptr[   j];                                         \

  1320.         ptr[-1-j] = tmp0 * csa_table[j][0] - tmp1 * csa_table[j][1];    \

  1321.         ptr[   j] = tmp0 * csa_table[j][1] + tmp1 * csa_table[j][0];    \

  1322.     } while (0)

  1323. #else

  1324. #define AA(j) do {                                              \

  1325.         int tmp0 = ptr[-1-j];                                   \

  1326.         int tmp1 = ptr[   j];                                   \

  1327.         int tmp2 = MULH(tmp0 + tmp1, csa_table[j][0]);          \

  1328.         ptr[-1-j] = 4*(tmp2 - MULH(tmp1, csa_table[j][2]));     \

  1329.         ptr[   j] = 4*(tmp2 + MULH(tmp0, csa_table[j][3]));     \

  1330.     } while (0)

  1331. #endif

  1332. 

  1333. static void compute_antialias(MPADecodeContext *s, GranuleDef *g)

  1334. {

  1335.     INTFLOAT *ptr;

  1336.     int n, i;

  1337. 

  1338.     /* we antialias only "long" bands */

  1339.     if (g->block_type == 2) {

  1340.         if (!g->switch_point)

  1341.             return;

  1342.         /* XXX: check this for 8000Hz case */

  1343.         n = 1;

  1344.     } else {

  1345.         n = SBLIMIT - 1;

  1346.     }

  1347. 

  1348.     ptr = g->sb_hybrid + 18;

  1349.     for(i = n;i > 0;i--) {

  1350.         AA(0);

  1351.         AA(1);

  1352.         AA(2);

  1353.         AA(3);

  1354.         AA(4);

  1355.         AA(5);

  1356.         AA(6);

  1357.         AA(7);

  1358. 

  1359.         ptr += 18;

  1360.     }

  1361. }

  1362. 

  1363. static void compute_imdct(MPADecodeContext *s,

  1364.                           GranuleDef *g,

  1365.                           INTFLOAT *sb_samples,

  1366.                           INTFLOAT *mdct_buf)

  1367. {

  1368.     INTFLOAT *win, *win1, *out_ptr, *ptr, *buf, *ptr1;

  1369.     INTFLOAT out2[12];

  1370.     int i, j, mdct_long_end, sblimit;

  1371. 

  1372.     /* find last non zero block */

  1373.     ptr = g->sb_hybrid + 576;

  1374.     ptr1 = g->sb_hybrid + 2 * 18;

  1375.     while (ptr >= ptr1) {

  1376.         int32_t *p;

  1377.         ptr -= 6;

  1378.         p= (int32_t*)ptr;

  1379.         if(p[0] | p[1] | p[2] | p[3] | p[4] | p[5])

  1380.             break;

  1381.     }

  1382.     sblimit = ((ptr - g->sb_hybrid) / 18) + 1;

  1383. 

  1384.     if (g->block_type == 2) {

  1385.         /* XXX: check for 8000 Hz */

  1386.         if (g->switch_point)

  1387.             mdct_long_end = 2;

  1388.         else

  1389.             mdct_long_end = 0;

  1390.     } else {

  1391.         mdct_long_end = sblimit;

  1392.     }

  1393. 

  1394.     buf = mdct_buf;

  1395.     ptr = g->sb_hybrid;

  1396.     for(j=0;j<mdct_long_end;j++) {

  1397.         /* apply window & overlap with previous buffer */

  1398.         out_ptr = sb_samples + j;

  1399.         /* select window */

  1400.         if (g->switch_point && j < 2)

  1401.             win1 = mdct_win[0];

  1402.         else

  1403.             win1 = mdct_win[g->block_type];

  1404.         /* select frequency inversion */

  1405.         win = win1 + ((4 * 36) & -(j & 1));

  1406.         imdct36(out_ptr, buf, ptr, win);

  1407.         out_ptr += 18*SBLIMIT;

  1408.         ptr += 18;

  1409.         buf += 18;

  1410.     }

  1411.     for(j=mdct_long_end;j<sblimit;j++) {

  1412.         /* select frequency inversion */

  1413.         win = mdct_win[2] + ((4 * 36) & -(j & 1));

  1414.         out_ptr = sb_samples + j;

  1415. 

  1416.         for(i=0; i<6; i++){

  1417.             *out_ptr = buf[i];

  1418.             out_ptr += SBLIMIT;

  1419.         }

  1420.         imdct12(out2, ptr + 0);

  1421.         for(i=0;i<6;i++) {

  1422.             *out_ptr     = MULH3(out2[i    ], win[i    ], 1) + buf[i + 6*1];

  1423.             buf[i + 6*2] = MULH3(out2[i + 6], win[i + 6], 1);

  1424.             out_ptr += SBLIMIT;

  1425.         }

  1426.         imdct12(out2, ptr + 1);

  1427.         for(i=0;i<6;i++) {

  1428.             *out_ptr     = MULH3(out2[i    ], win[i    ], 1) + buf[i + 6*2];

  1429.             buf[i + 6*0] = MULH3(out2[i + 6], win[i + 6], 1);

  1430.             out_ptr += SBLIMIT;

  1431.         }

  1432.         imdct12(out2, ptr + 2);

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

  1434.             buf[i + 6*0] = MULH3(out2[i    ], win[i    ], 1) + buf[i + 6*0];

  1435.             buf[i + 6*1] = MULH3(out2[i + 6], win[i + 6], 1);

  1436.             buf[i + 6*2] = 0;

  1437.         }

  1438.         ptr += 18;

  1439.         buf += 18;

  1440.     }

  1441.     /* zero bands */

  1442.     for(j=sblimit;j<SBLIMIT;j++) {

  1443.         /* overlap */

  1444.         out_ptr = sb_samples + j;

  1445.         for(i=0;i<18;i++) {

  1446.             *out_ptr = buf[i];

  1447.             buf[i] = 0;

  1448.             out_ptr += SBLIMIT;

  1449.         }

  1450.         buf += 18;

  1451.     }

  1452. }

  1453. 

  1454. /* main layer3 decoding function */

  1455. static int mp_decode_layer3(MPADecodeContext *s)

  1456. {

  1457.     int nb_granules, main_data_begin;

  1458.     int gr, ch, blocksplit_flag, i, j, k, n, bits_pos;

  1459.     GranuleDef *g;

  1460.     int16_t exponents[576]; //FIXME try INTFLOAT

  1461. 

  1462.     /* read side info */

  1463.     if (s->lsf) {

  1464.         main_data_begin = get_bits(&s->gb, 8);

  1465.         skip_bits(&s->gb, s->nb_channels);

  1466.         nb_granules = 1;

  1467.     } else {

  1468.         main_data_begin = get_bits(&s->gb, 9);

  1469.         if (s->nb_channels == 2)

  1470.             skip_bits(&s->gb, 3);

  1471.         else

  1472.             skip_bits(&s->gb, 5);

  1473.         nb_granules = 2;

  1474.         for(ch=0;ch<s->nb_channels;ch++) {

  1475.             s->granules[ch][0].scfsi = 0;/* all scale factors are transmitted */

  1476.             s->granules[ch][1].scfsi = get_bits(&s->gb, 4);

  1477.         }

  1478.     }

  1479. 

  1480.     for(gr=0;gr<nb_granules;gr++) {

  1481.         for(ch=0;ch<s->nb_channels;ch++) {

  1482.             av_dlog(s->avctx, "gr=%d ch=%d: side_info\n", gr, ch);

  1483.             g = &s->granules[ch][gr];

  1484.             g->part2_3_length = get_bits(&s->gb, 12);

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

  1486.             if(g->big_values > 288){

  1487.                 av_log(s->avctx, AV_LOG_ERROR, "big_values too big\n");

  1488.                 return -1;

  1489.             }

  1490. 

  1491.             g->global_gain = get_bits(&s->gb, 8);

  1492.             /* if MS stereo only is selected, we precompute the

  1493.                1/sqrt(2) renormalization factor */

  1494.             if ((s->mode_ext & (MODE_EXT_MS_STEREO | MODE_EXT_I_STEREO)) ==

  1495.                 MODE_EXT_MS_STEREO)

  1496.                 g->global_gain -= 2;

  1497.             if (s->lsf)

  1498.                 g->scalefac_compress = get_bits(&s->gb, 9);

  1499.             else

  1500.                 g->scalefac_compress = get_bits(&s->gb, 4);

  1501.             blocksplit_flag = get_bits1(&s->gb);

  1502.             if (blocksplit_flag) {

  1503.                 g->block_type = get_bits(&s->gb, 2);

  1504.                 if (g->block_type == 0){

  1505.                     av_log(s->avctx, AV_LOG_ERROR, "invalid block type\n");

  1506.                     return -1;

  1507.                 }

  1508.                 g->switch_point = get_bits1(&s->gb);

  1509.                 for(i=0;i<2;i++)

  1510.                     g->table_select[i] = get_bits(&s->gb, 5);

  1511.                 for(i=0;i<3;i++)

  1512.                     g->subblock_gain[i] = get_bits(&s->gb, 3);

  1513.                 ff_init_short_region(s, g);

  1514.             } else {

  1515.                 int region_address1, region_address2;

  1516.                 g->block_type = 0;

  1517.                 g->switch_point = 0;

  1518.                 for(i=0;i<3;i++)

  1519.                     g->table_select[i] = get_bits(&s->gb, 5);

  1520.                 /* compute huffman coded region sizes */

  1521.                 region_address1 = get_bits(&s->gb, 4);

  1522.                 region_address2 = get_bits(&s->gb, 3);

  1523.                 av_dlog(s->avctx, "region1=%d region2=%d\n",

  1524.                         region_address1, region_address2);

  1525.                 ff_init_long_region(s, g, region_address1, region_address2);

  1526.             }

  1527.             ff_region_offset2size(g);

  1528.             ff_compute_band_indexes(s, g);

  1529. 

  1530.             g->preflag = 0;

  1531.             if (!s->lsf)

  1532.                 g->preflag = get_bits1(&s->gb);

  1533.             g->scalefac_scale = get_bits1(&s->gb);

  1534.             g->count1table_select = get_bits1(&s->gb);

  1535.             av_dlog(s->avctx, "block_type=%d switch_point=%d\n",

  1536.                     g->block_type, g->switch_point);

  1537.         }

  1538.     }

  1539. 

  1540.   if (!s->adu_mode) {

  1541.     const uint8_t *ptr = s->gb.buffer + (get_bits_count(&s->gb)>>3);

  1542.     assert((get_bits_count(&s->gb) & 7) == 0);

  1543.     /* now we get bits from the main_data_begin offset */

  1544.     av_dlog(s->avctx, "seekback: %d\n", main_data_begin);

  1545. //av_log(NULL, AV_LOG_ERROR, "backstep:%d, lastbuf:%d\n", main_data_begin, s->last_buf_size);

  1546. 

  1547.     memcpy(s->last_buf + s->last_buf_size, ptr, EXTRABYTES);

  1548.     s->in_gb= s->gb;

  1549.         init_get_bits(&s->gb, s->last_buf, s->last_buf_size*8);

  1550.         skip_bits_long(&s->gb, 8*(s->last_buf_size - main_data_begin));

  1551.   }

  1552. 

  1553.     for(gr=0;gr<nb_granules;gr++) {

  1554.         for(ch=0;ch<s->nb_channels;ch++) {

  1555.             g = &s->granules[ch][gr];

  1556.             if(get_bits_count(&s->gb)<0){

  1557.                 av_log(s->avctx, AV_LOG_DEBUG, "mdb:%d, lastbuf:%d skipping granule %d\n",

  1558.                                             main_data_begin, s->last_buf_size, gr);

  1559.                 skip_bits_long(&s->gb, g->part2_3_length);

  1560.                 memset(g->sb_hybrid, 0, sizeof(g->sb_hybrid));

  1561.                 if(get_bits_count(&s->gb) >= s->gb.size_in_bits && s->in_gb.buffer){

  1562.                     skip_bits_long(&s->in_gb, get_bits_count(&s->gb) - s->gb.size_in_bits);

  1563.                     s->gb= s->in_gb;

  1564.                     s->in_gb.buffer=NULL;

  1565.                 }

  1566.                 continue;

  1567.             }

  1568. 

  1569.             bits_pos = get_bits_count(&s->gb);

  1570. 

  1571.             if (!s->lsf) {

  1572.                 uint8_t *sc;

  1573.                 int slen, slen1, slen2;

  1574. 

  1575.                 /* MPEG1 scale factors */

  1576.                 slen1 = slen_table[0][g->scalefac_compress];

  1577.                 slen2 = slen_table[1][g->scalefac_compress];

  1578.                 av_dlog(s->avctx, "slen1=%d slen2=%d\n", slen1, slen2);

  1579.                 if (g->block_type == 2) {

  1580.                     n = g->switch_point ? 17 : 18;

  1581.                     j = 0;

  1582.                     if(slen1){

  1583.                         for(i=0;i<n;i++)

  1584.                             g->scale_factors[j++] = get_bits(&s->gb, slen1);

  1585.                     }else{

  1586.                         for(i=0;i<n;i++)

  1587.                             g->scale_factors[j++] = 0;

  1588.                     }

  1589.                     if(slen2){

  1590.                         for(i=0;i<18;i++)

  1591.                             g->scale_factors[j++] = get_bits(&s->gb, slen2);

  1592.                         for(i=0;i<3;i++)

  1593.                             g->scale_factors[j++] = 0;

  1594.                     }else{

  1595.                         for(i=0;i<21;i++)

  1596.                             g->scale_factors[j++] = 0;

  1597.                     }

  1598.                 } else {

  1599.                     sc = s->granules[ch][0].scale_factors;

  1600.                     j = 0;

  1601.                     for(k=0;k<4;k++) {

  1602.                         n = (k == 0 ? 6 : 5);

  1603.                         if ((g->scfsi & (0x8 >> k)) == 0) {

  1604.                             slen = (k < 2) ? slen1 : slen2;

  1605.                             if(slen){

  1606.                                 for(i=0;i<n;i++)

  1607.                                     g->scale_factors[j++] = get_bits(&s->gb, slen);

  1608.                             }else{

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

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

  1611.                             }

  1612.                         } else {

  1613.                             /* simply copy from last granule */

  1614.                             for(i=0;i<n;i++) {

  1615.                                 g->scale_factors[j] = sc[j];

  1616.                                 j++;

  1617.                             }

  1618.                         }

  1619.                     }

  1620.                     g->scale_factors[j++] = 0;

  1621.                 }

  1622.             } else {

  1623.                 int tindex, tindex2, slen[4], sl, sf;

  1624. 

  1625.                 /* LSF scale factors */

  1626.                 if (g->block_type == 2) {

  1627.                     tindex = g->switch_point ? 2 : 1;

  1628.                 } else {

  1629.                     tindex = 0;

  1630.                 }

  1631.                 sf = g->scalefac_compress;

  1632.                 if ((s->mode_ext & MODE_EXT_I_STEREO) && ch == 1) {

  1633.                     /* intensity stereo case */

  1634.                     sf >>= 1;

  1635.                     if (sf < 180) {

  1636.                         lsf_sf_expand(slen, sf, 6, 6, 0);

  1637.                         tindex2 = 3;

  1638.                     } else if (sf < 244) {

  1639.                         lsf_sf_expand(slen, sf - 180, 4, 4, 0);

  1640.                         tindex2 = 4;

  1641.                     } else {

  1642.                         lsf_sf_expand(slen, sf - 244, 3, 0, 0);

  1643.                         tindex2 = 5;

  1644.                     }

  1645.                 } else {

  1646.                     /* normal case */

  1647.                     if (sf < 400) {

  1648.                         lsf_sf_expand(slen, sf, 5, 4, 4);

  1649.                         tindex2 = 0;

  1650.                     } else if (sf < 500) {

  1651.                         lsf_sf_expand(slen, sf - 400, 5, 4, 0);

  1652.                         tindex2 = 1;

  1653.                     } else {

  1654.                         lsf_sf_expand(slen, sf - 500, 3, 0, 0);

  1655.                         tindex2 = 2;

  1656.                         g->preflag = 1;

  1657.                     }

  1658.                 }

  1659. 

  1660.                 j = 0;

  1661.                 for(k=0;k<4;k++) {

  1662.                     n = lsf_nsf_table[tindex2][tindex][k];

  1663.                     sl = slen[k];

  1664.                     if(sl){

  1665.                         for(i=0;i<n;i++)

  1666.                             g->scale_factors[j++] = get_bits(&s->gb, sl);

  1667.                     }else{

  1668.                         for(i=0;i<n;i++)

  1669.                             g->scale_factors[j++] = 0;

  1670.                     }

  1671.                 }

  1672.                 /* XXX: should compute exact size */

  1673.                 for(;j<40;j++)

  1674.                     g->scale_factors[j] = 0;

  1675.             }

  1676. 

  1677.             exponents_from_scale_factors(s, g, exponents);

  1678. 

  1679.             /* read Huffman coded residue */

  1680.             huffman_decode(s, g, exponents, bits_pos + g->part2_3_length);

  1681.         } /* ch */

  1682. 

  1683.         if (s->nb_channels == 2)

  1684.             compute_stereo(s, &s->granules[0][gr], &s->granules[1][gr]);

  1685. 

  1686.         for(ch=0;ch<s->nb_channels;ch++) {

  1687.             g = &s->granules[ch][gr];

  1688. 

  1689.             reorder_block(s, g);

  1690.             compute_antialias(s, g);

  1691.             compute_imdct(s, g, &s->sb_samples[ch][18 * gr][0], s->mdct_buf[ch]);

  1692.         }

  1693.     } /* gr */

  1694.     if(get_bits_count(&s->gb)<0)

  1695.         skip_bits_long(&s->gb, -get_bits_count(&s->gb));

  1696.     return nb_granules * 18;

  1697. }

  1698. 

  1699. static int mp_decode_frame(MPADecodeContext *s,

  1700.                            OUT_INT *samples, const uint8_t *buf, int buf_size)

  1701. {

  1702.     int i, nb_frames, ch;

  1703.     OUT_INT *samples_ptr;

  1704. 

  1705.     init_get_bits(&s->gb, buf + HEADER_SIZE, (buf_size - HEADER_SIZE)*8);

  1706. 

  1707.     /* skip error protection field */

  1708.     if (s->error_protection)

  1709.         skip_bits(&s->gb, 16);

  1710. 

  1711.     av_dlog(s->avctx, "frame %d:\n", s->frame_count);

  1712.     switch(s->layer) {

  1713.     case 1:

  1714.         s->avctx->frame_size = 384;

  1715.         nb_frames = mp_decode_layer1(s);

  1716.         break;

  1717.     case 2:

  1718.         s->avctx->frame_size = 1152;

  1719.         nb_frames = mp_decode_layer2(s);

  1720.         break;

  1721.     case 3:

  1722.         s->avctx->frame_size = s->lsf ? 576 : 1152;

  1723.     default:

  1724.         nb_frames = mp_decode_layer3(s);

  1725. 

  1726.         s->last_buf_size=0;

  1727.         if(s->in_gb.buffer){

  1728.             align_get_bits(&s->gb);

  1729.             i= get_bits_left(&s->gb)>>3;

  1730.             if(i >= 0 && i <= BACKSTEP_SIZE){

  1731.                 memmove(s->last_buf, s->gb.buffer + (get_bits_count(&s->gb)>>3), i);

  1732.                 s->last_buf_size=i;

  1733.             }else

  1734.                 av_log(s->avctx, AV_LOG_ERROR, "invalid old backstep %d\n", i);

  1735.             s->gb= s->in_gb;

  1736.             s->in_gb.buffer= NULL;

  1737.         }

  1738. 

  1739.         align_get_bits(&s->gb);

  1740.         assert((get_bits_count(&s->gb) & 7) == 0);

  1741.         i= get_bits_left(&s->gb)>>3;

  1742. 

  1743.         if(i<0 || i > BACKSTEP_SIZE || nb_frames<0){

  1744.             if(i<0)

  1745.                 av_log(s->avctx, AV_LOG_ERROR, "invalid new backstep %d\n", i);

  1746.             i= FFMIN(BACKSTEP_SIZE, buf_size - HEADER_SIZE);

  1747.         }

  1748.         assert(i <= buf_size - HEADER_SIZE && i>= 0);

  1749.         memcpy(s->last_buf + s->last_buf_size, s->gb.buffer + buf_size - HEADER_SIZE - i, i);

  1750.         s->last_buf_size += i;

  1751. 

  1752.         break;

  1753.     }

  1754. 

  1755.     /* apply the synthesis filter */

  1756.     for(ch=0;ch<s->nb_channels;ch++) {

  1757.         samples_ptr = samples + ch;

  1758.         for(i=0;i<nb_frames;i++) {

  1759.             RENAME(ff_mpa_synth_filter)(

  1760.                          &s->mpadsp,

  1761.                          s->synth_buf[ch], &(s->synth_buf_offset[ch]),

  1762.                          RENAME(ff_mpa_synth_window), &s->dither_state,

  1763.                          samples_ptr, s->nb_channels,

  1764.                          s->sb_samples[ch][i]);

  1765.             samples_ptr += 32 * s->nb_channels;

  1766.         }

  1767.     }

  1768. 

  1769.     return nb_frames * 32 * sizeof(OUT_INT) * s->nb_channels;

  1770. }

  1771. 

  1772. static int decode_frame(AVCodecContext * avctx,

  1773.                         void *data, int *data_size,

  1774.                         AVPacket *avpkt)

  1775. {

  1776.     const uint8_t *buf = avpkt->data;

  1777.     int buf_size = avpkt->size;

  1778.     MPADecodeContext *s = avctx->priv_data;

  1779.     uint32_t header;

  1780.     int out_size;

  1781.     OUT_INT *out_samples = data;

  1782. 

  1783.     if(buf_size < HEADER_SIZE)

  1784.         return -1;

  1785. 

  1786.     header = AV_RB32(buf);

  1787.     if(ff_mpa_check_header(header) < 0){

  1788.         av_log(avctx, AV_LOG_ERROR, "Header missing\n");

  1789.         return -1;

  1790.     }

  1791. 

  1792.     if (ff_mpegaudio_decode_header((MPADecodeHeader *)s, header) == 1) {

  1793.         /* free format: prepare to compute frame size */

  1794.         s->frame_size = -1;

  1795.         return -1;

  1796.     }

  1797.     /* update codec info */

  1798.     avctx->channels = s->nb_channels;

  1799.     avctx->channel_layout = s->nb_channels == 1 ? AV_CH_LAYOUT_MONO : AV_CH_LAYOUT_STEREO;

  1800.     if (!avctx->bit_rate)

  1801.         avctx->bit_rate = s->bit_rate;

  1802.     avctx->sub_id = s->layer;

  1803. 

  1804.     if(*data_size < 1152*avctx->channels*sizeof(OUT_INT))

  1805.         return -1;

  1806.     *data_size = 0;

  1807. 

  1808.     if(s->frame_size<=0 || s->frame_size > buf_size){

  1809.         av_log(avctx, AV_LOG_ERROR, "incomplete frame\n");

  1810.         return -1;

  1811.     }else if(s->frame_size < buf_size){

  1812.         av_log(avctx, AV_LOG_ERROR, "incorrect frame size\n");

  1813.         buf_size= s->frame_size;

  1814.     }

  1815. 

  1816.     out_size = mp_decode_frame(s, out_samples, buf, buf_size);

  1817.     if(out_size>=0){

  1818.         *data_size = out_size;

  1819.         avctx->sample_rate = s->sample_rate;

  1820.         //FIXME maybe move the other codec info stuff from above here too

  1821.     }else

  1822.         av_log(avctx, AV_LOG_DEBUG, "Error while decoding MPEG audio frame.\n"); //FIXME return -1 / but also return the number of bytes consumed

  1823.     s->frame_size = 0;

  1824.     return buf_size;

  1825. }

  1826. 

  1827. static void flush(AVCodecContext *avctx){

  1828.     MPADecodeContext *s = avctx->priv_data;

  1829.     memset(s->synth_buf, 0, sizeof(s->synth_buf));

  1830.     s->last_buf_size= 0;

  1831. }

  1832. 

  1833. #if CONFIG_MP3ADU_DECODER || CONFIG_MP3ADUFLOAT_DECODER

  1834. static int decode_frame_adu(AVCodecContext * avctx,

  1835.                         void *data, int *data_size,

  1836.                         AVPacket *avpkt)

  1837. {

  1838.     const uint8_t *buf = avpkt->data;

  1839.     int buf_size = avpkt->size;

  1840.     MPADecodeContext *s = avctx->priv_data;

  1841.     uint32_t header;

  1842.     int len, out_size;

  1843.     OUT_INT *out_samples = data;

  1844. 

  1845.     len = buf_size;

  1846. 

  1847.     // Discard too short frames

  1848.     if (buf_size < HEADER_SIZE) {

  1849.         *data_size = 0;

  1850.         return buf_size;

  1851.     }

  1852. 

  1853. 

  1854.     if (len > MPA_MAX_CODED_FRAME_SIZE)

  1855.         len = MPA_MAX_CODED_FRAME_SIZE;

  1856. 

  1857.     // Get header and restore sync word

  1858.     header = AV_RB32(buf) | 0xffe00000;

  1859. 

  1860.     if (ff_mpa_check_header(header) < 0) { // Bad header, discard frame

  1861.         *data_size = 0;

  1862.         return buf_size;

  1863.     }

  1864. 

  1865.     ff_mpegaudio_decode_header((MPADecodeHeader *)s, header);

  1866.     /* update codec info */

  1867.     avctx->sample_rate = s->sample_rate;

  1868.     avctx->channels = s->nb_channels;

  1869.     if (!avctx->bit_rate)

  1870.         avctx->bit_rate = s->bit_rate;

  1871.     avctx->sub_id = s->layer;

  1872. 

  1873.     s->frame_size = len;

  1874. 

  1875.     if (avctx->parse_only) {

  1876.         out_size = buf_size;

  1877.     } else {

  1878.         out_size = mp_decode_frame(s, out_samples, buf, buf_size);

  1879.     }

  1880. 

  1881.     *data_size = out_size;

  1882.     return buf_size;

  1883. }

  1884. #endif /* CONFIG_MP3ADU_DECODER || CONFIG_MP3ADUFLOAT_DECODER */

  1885. 

  1886. #if CONFIG_MP3ON4_DECODER || CONFIG_MP3ON4FLOAT_DECODER

  1887. 

  1888. /**

  1889.  * Context for MP3On4 decoder

  1890.  */

  1891. typedef struct MP3On4DecodeContext {

  1892.     int frames;   ///< number of mp3 frames per block (number of mp3 decoder instances)

  1893.     int syncword; ///< syncword patch

  1894.     const uint8_t *coff; ///< channels offsets in output buffer

  1895.     MPADecodeContext *mp3decctx[5]; ///< MPADecodeContext for every decoder instance

  1896. } MP3On4DecodeContext;

  1897. 

  1898. #include "mpeg4audio.h"

  1899. 

  1900. /* Next 3 arrays are indexed by channel config number (passed via codecdata) */

  1901. static const uint8_t mp3Frames[8] = {0,1,1,2,3,3,4,5};   /* number of mp3 decoder instances */

  1902. /* offsets into output buffer, assume output order is FL FR BL BR C LFE */

  1903. static const uint8_t chan_offset[8][5] = {

  1904.     {0},

  1905.     {0},            // C

  1906.     {0},            // FLR

  1907.     {2,0},          // C FLR

  1908.     {2,0,3},        // C FLR BS

  1909.     {4,0,2},        // C FLR BLRS

  1910.     {4,0,2,5},      // C FLR BLRS LFE

  1911.     {4,0,2,6,5},    // C FLR BLRS BLR LFE

  1912. };

  1913. 

  1914. 

  1915. static int decode_init_mp3on4(AVCodecContext * avctx)

  1916. {

  1917.     MP3On4DecodeContext *s = avctx->priv_data;

  1918.     MPEG4AudioConfig cfg;

  1919.     int i;

  1920. 

  1921.     if ((avctx->extradata_size < 2) || (avctx->extradata == NULL)) {

  1922.         av_log(avctx, AV_LOG_ERROR, "Codec extradata missing or too short.\n");

  1923.         return -1;

  1924.     }

  1925. 

  1926.     ff_mpeg4audio_get_config(&cfg, avctx->extradata, avctx->extradata_size);

  1927.     if (!cfg.chan_config || cfg.chan_config > 7) {

  1928.         av_log(avctx, AV_LOG_ERROR, "Invalid channel config number.\n");

  1929.         return -1;

  1930.     }

  1931.     s->frames = mp3Frames[cfg.chan_config];

  1932.     s->coff = chan_offset[cfg.chan_config];

  1933.     avctx->channels = ff_mpeg4audio_channels[cfg.chan_config];

  1934. 

  1935.     if (cfg.sample_rate < 16000)

  1936.         s->syncword = 0xffe00000;

  1937.     else

  1938.         s->syncword = 0xfff00000;

  1939. 

  1940.     /* Init the first mp3 decoder in standard way, so that all tables get builded

  1941.      * We replace avctx->priv_data with the context of the first decoder so that

  1942.      * decode_init() does not have to be changed.

  1943.      * Other decoders will be initialized here copying data from the first context

  1944.      */

  1945.     // Allocate zeroed memory for the first decoder context

  1946.     s->mp3decctx[0] = av_mallocz(sizeof(MPADecodeContext));

  1947.     // Put decoder context in place to make init_decode() happy

  1948.     avctx->priv_data = s->mp3decctx[0];

  1949.     decode_init(avctx);

  1950.     // Restore mp3on4 context pointer

  1951.     avctx->priv_data = s;

  1952.     s->mp3decctx[0]->adu_mode = 1; // Set adu mode

  1953. 

  1954.     /* Create a separate codec/context for each frame (first is already ok).

  1955.      * Each frame is 1 or 2 channels - up to 5 frames allowed

  1956.      */

  1957.     for (i = 1; i < s->frames; i++) {

  1958.         s->mp3decctx[i] = av_mallocz(sizeof(MPADecodeContext));

  1959.         s->mp3decctx[i]->adu_mode = 1;

  1960.         s->mp3decctx[i]->avctx = avctx;

  1961.     }

  1962. 

  1963.     return 0;

  1964. }

  1965. 

  1966. 

  1967. static av_cold int decode_close_mp3on4(AVCodecContext * avctx)

  1968. {

  1969.     MP3On4DecodeContext *s = avctx->priv_data;

  1970.     int i;

  1971. 

  1972.     for (i = 0; i < s->frames; i++)

  1973.         av_free(s->mp3decctx[i]);

  1974. 

  1975.     return 0;

  1976. }

  1977. 

  1978. 

  1979. static int decode_frame_mp3on4(AVCodecContext * avctx,

  1980.                         void *data, int *data_size,

  1981.                         AVPacket *avpkt)

  1982. {

  1983.     const uint8_t *buf = avpkt->data;

  1984.     int buf_size = avpkt->size;

  1985.     MP3On4DecodeContext *s = avctx->priv_data;

  1986.     MPADecodeContext *m;

  1987.     int fsize, len = buf_size, out_size = 0;

  1988.     uint32_t header;

  1989.     OUT_INT *out_samples = data;

  1990.     OUT_INT decoded_buf[MPA_FRAME_SIZE * MPA_MAX_CHANNELS];

  1991.     OUT_INT *outptr, *bp;

  1992.     int fr, j, n;

  1993. 

  1994.     if(*data_size < MPA_FRAME_SIZE * MPA_MAX_CHANNELS * s->frames * sizeof(OUT_INT))

  1995.         return -1;

  1996. 

  1997.     *data_size = 0;

  1998.     // Discard too short frames

  1999.     if (buf_size < HEADER_SIZE)

  2000.         return -1;

  2001. 

  2002.     // If only one decoder interleave is not needed

  2003.     outptr = s->frames == 1 ? out_samples : decoded_buf;

  2004. 

  2005.     avctx->bit_rate = 0;

  2006. 

  2007.     for (fr = 0; fr < s->frames; fr++) {

  2008.         fsize = AV_RB16(buf) >> 4;

  2009.         fsize = FFMIN3(fsize, len, MPA_MAX_CODED_FRAME_SIZE);

  2010.         m = s->mp3decctx[fr];

  2011.         assert (m != NULL);

  2012. 

  2013.         header = (AV_RB32(buf) & 0x000fffff) | s->syncword; // patch header

  2014. 

  2015.         if (ff_mpa_check_header(header) < 0) // Bad header, discard block

  2016.             break;

  2017. 

  2018.         ff_mpegaudio_decode_header((MPADecodeHeader *)m, header);

  2019.         out_size += mp_decode_frame(m, outptr, buf, fsize);

  2020.         buf += fsize;

  2021.         len -= fsize;

  2022. 

  2023.         if(s->frames > 1) {

  2024.             n = m->avctx->frame_size*m->nb_channels;

  2025.             /* interleave output data */

  2026.             bp = out_samples + s->coff[fr];

  2027.             if(m->nb_channels == 1) {

  2028.                 for(j = 0; j < n; j++) {

  2029.                     *bp = decoded_buf[j];

  2030.                     bp += avctx->channels;

  2031.                 }

  2032.             } else {

  2033.                 for(j = 0; j < n; j++) {

  2034.                     bp[0] = decoded_buf[j++];

  2035.                     bp[1] = decoded_buf[j];

  2036.                     bp += avctx->channels;

  2037.                 }

  2038.             }

  2039.         }

  2040.         avctx->bit_rate += m->bit_rate;

  2041.     }

  2042. 

  2043.     /* update codec info */

  2044.     avctx->sample_rate = s->mp3decctx[0]->sample_rate;

  2045. 

  2046.     *data_size = out_size;

  2047.     return buf_size;

  2048. }

  2049. #endif /* CONFIG_MP3ON4_DECODER || CONFIG_MP3ON4FLOAT_DECODER */

  2050. 

  2051. #if !CONFIG_FLOAT

  2052. #if CONFIG_MP1_DECODER

  2053. AVCodec ff_mp1_decoder =

  2054. {

  2055.     "mp1",

  2056.     AVMEDIA_TYPE_AUDIO,

  2057.     CODEC_ID_MP1,

  2058.     sizeof(MPADecodeContext),

  2059.     decode_init,

  2060.     NULL,

  2061.     NULL,

  2062.     decode_frame,

  2063.     CODEC_CAP_PARSE_ONLY,

  2064.     .flush= flush,

  2065.     .long_name= NULL_IF_CONFIG_SMALL("MP1 (MPEG audio layer 1)"),

  2066. };

  2067. #endif

  2068. #if CONFIG_MP2_DECODER

  2069. AVCodec ff_mp2_decoder =

  2070. {

  2071.     "mp2",

  2072.     AVMEDIA_TYPE_AUDIO,

  2073.     CODEC_ID_MP2,

  2074.     sizeof(MPADecodeContext),

  2075.     decode_init,

  2076.     NULL,

  2077.     NULL,

  2078.     decode_frame,

  2079.     CODEC_CAP_PARSE_ONLY,

  2080.     .flush= flush,

  2081.     .long_name= NULL_IF_CONFIG_SMALL("MP2 (MPEG audio layer 2)"),

  2082. };

  2083. #endif

  2084. #if CONFIG_MP3_DECODER

  2085. AVCodec ff_mp3_decoder =

  2086. {

  2087.     "mp3",

  2088.     AVMEDIA_TYPE_AUDIO,

  2089.     CODEC_ID_MP3,

  2090.     sizeof(MPADecodeContext),

  2091.     decode_init,

  2092.     NULL,

  2093.     NULL,

  2094.     decode_frame,

  2095.     CODEC_CAP_PARSE_ONLY,

  2096.     .flush= flush,

  2097.     .long_name= NULL_IF_CONFIG_SMALL("MP3 (MPEG audio layer 3)"),

  2098. };

  2099. #endif

  2100. #if CONFIG_MP3ADU_DECODER

  2101. AVCodec ff_mp3adu_decoder =

  2102. {

  2103.     "mp3adu",

  2104.     AVMEDIA_TYPE_AUDIO,

  2105.     CODEC_ID_MP3ADU,

  2106.     sizeof(MPADecodeContext),

  2107.     decode_init,

  2108.     NULL,

  2109.     NULL,

  2110.     decode_frame_adu,

  2111.     CODEC_CAP_PARSE_ONLY,

  2112.     .flush= flush,

  2113.     .long_name= NULL_IF_CONFIG_SMALL("ADU (Application Data Unit) MP3 (MPEG audio layer 3)"),

  2114. };

  2115. #endif

  2116. #if CONFIG_MP3ON4_DECODER

  2117. AVCodec ff_mp3on4_decoder =

  2118. {

  2119.     "mp3on4",

  2120.     AVMEDIA_TYPE_AUDIO,

  2121.     CODEC_ID_MP3ON4,

  2122.     sizeof(MP3On4DecodeContext),

  2123.     decode_init_mp3on4,

  2124.     NULL,

  2125.     decode_close_mp3on4,

  2126.     decode_frame_mp3on4,

  2127.     .flush= flush,

  2128.     .long_name= NULL_IF_CONFIG_SMALL("MP3onMP4"),

  2129. };

  2130. #endif

  2131. #endif