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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/channel_layout.h"

  28. #include "avcodec.h"

  29. #include "get_bits.h"

  30. #include "mathops.h"

  31. #include "mpegaudiodsp.h"

  32. #include "dsputil.h"

  33. 

  34. /*

  35.  * TODO:

  36.  *  - test lsf / mpeg25 extensively.

  37.  */

  38. 

  39. #include "mpegaudio.h"

  40. #include "mpegaudiodecheader.h"

  41. 

  42. #define BACKSTEP_SIZE 512

  43. #define EXTRABYTES 24

  44. #define LAST_BUF_SIZE 2 * BACKSTEP_SIZE + EXTRABYTES

  45. 

  46. /* layer 3 "granule" */

  47. typedef struct GranuleDef {

  48.     uint8_t scfsi;

  49.     int part2_3_length;

  50.     int big_values;

  51.     int global_gain;

  52.     int scalefac_compress;

  53.     uint8_t block_type;

  54.     uint8_t switch_point;

  55.     int table_select[3];

  56.     int subblock_gain[3];

  57.     uint8_t scalefac_scale;

  58.     uint8_t count1table_select;

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

  60.     int preflag;

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

  62.     uint8_t scale_factors[40];

  63.     DECLARE_ALIGNED(16, INTFLOAT, sb_hybrid)[SBLIMIT * 18]; /* 576 samples */

  64. } GranuleDef;

  65. 

  66. typedef struct MPADecodeContext {

  67.     MPA_DECODE_HEADER

  68.     uint8_t last_buf[LAST_BUF_SIZE];

  69.     int last_buf_size;

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

  71.     uint32_t free_format_next_header;

  72.     GetBitContext gb;

  73.     GetBitContext in_gb;

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

  75.     int synth_buf_offset[MPA_MAX_CHANNELS];

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

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

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

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

  80.     int dither_state;

  81.     int err_recognition;

  82.     AVCodecContext* avctx;

  83.     MPADSPContext mpadsp;

  84.     DSPContext dsp;

  85.     AVFrame frame;

  86. } MPADecodeContext;

  87. 

  88. #if CONFIG_FLOAT

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

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

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

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

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

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

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

  96. #   define OUT_FMT AV_SAMPLE_FMT_FLT

  97. #else

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

  99. /* WARNING: only correct for positive numbers */

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

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

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

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

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

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

  106. #   define OUT_FMT AV_SAMPLE_FMT_S16

  107. #endif

  108. 

  109. /****************/

  110. 

  111. #define HEADER_SIZE 4

  112. 

  113. #include "mpegaudiodata.h"

  114. #include "mpegaudiodectab.h"

  115. 

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

  117. static VLC huff_vlc[16];

  118. static VLC_TYPE huff_vlc_tables[

  119.     0 + 128 + 128 + 128 + 130 + 128 + 154 + 166 +

  120.   142 + 204 + 190 + 170 + 542 + 460 + 662 + 414

  121.   ][2];

  122. static const int huff_vlc_tables_sizes[16] = {

  123.     0,  128,  128,  128,  130,  128,  154,  166,

  124.   142,  204,  190,  170,  542,  460,  662,  414

  125. };

  126. static VLC huff_quad_vlc[2];

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

  128. static const int huff_quad_vlc_tables_sizes[2] = { 128, 16 };

  129. /* computed from band_size_long */

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

  131. #include "mpegaudio_tablegen.h"

  132. /* intensity stereo coef table */

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

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

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

  136. 

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

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

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

  140. 

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

  142.     division_tab3, division_tab5, NULL, division_tab9

  143. };

  144. 

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

  146. static uint16_t scale_factor_modshift[64];

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

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

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

  150. 

  151. #define SCALE_GEN(v) \

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

  153. 

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

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

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

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

  158. };

  159. 

  160. /**

  161.  * Convert region offsets to region sizes and truncate

  162.  * size to big_values.

  163.  */

  164. static void ff_region_offset2size(GranuleDef *g)

  165. {

  166.     int i, k, j = 0;

  167.     g->region_size[2] = 576 / 2;

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

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

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

  171.         j = k;

  172.     }

  173. }

  174. 

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

  176. {

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

  178.         if (s->sample_rate_index != 8)

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

  180.         else

  181.             g->region_size[0] = (72 / 2);

  182.     } else {

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

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

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

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

  187.         else

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

  189.     }

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

  191. }

  192. 

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

  194. {

  195.     int l;

  196.     g->region_size[0] = band_index_long[s->sample_rate_index][ra1 + 1] >> 1;

  197.     /* should not overflow */

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

  199.     g->region_size[1] = band_index_long[s->sample_rate_index][      l] >> 1;

  200. }

  201. 

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

  203. {

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

  205.         if (g->switch_point) {

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

  207.                 long blocks.  For 8000Hz, we handle the 72 first

  208.                 exponents as long blocks */

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

  210.                 g->long_end = 8;

  211.             else

  212.                 g->long_end = 6;

  213. 

  214.             g->short_start = 3;

  215.         } else {

  216.             g->long_end    = 0;

  217.             g->short_start = 0;

  218.         }

  219.     } else {

  220.         g->short_start = 13;

  221.         g->long_end    = 22;

  222.     }

  223. }

  224. 

  225. /* layer 1 unscaling */

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

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

  228. {

  229.     int shift, mod;

  230.     int64_t val;

  231. 

  232.     shift   = scale_factor_modshift[scale_factor];

  233.     mod     = shift & 3;

  234.     shift >>= 2;

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

  236.     shift  += n;

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

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

  239. }

  240. 

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

  242. {

  243.     int shift, mod, val;

  244. 

  245.     shift   = scale_factor_modshift[scale_factor];

  246.     mod     = shift & 3;

  247.     shift >>= 2;

  248. 

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

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

  251.     if (shift > 0)

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

  253.     return val;

  254. }

  255. 

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

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

  258. {

  259.     unsigned int m;

  260.     int e;

  261. 

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

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

  264.     e -= exponent >> 2;

  265.     assert(e >= 1);

  266.     if (e > 31)

  267.         return 0;

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

  269. 

  270.     return m;

  271. }

  272. 

  273. static av_cold void decode_init_static(void)

  274. {

  275.     int i, j, k;

  276.     int offset;

  277. 

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

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

  280.         int shift, mod;

  281.         /* 1.0 (i = 3) is normalized to 2 ^ FRAC_BITS */

  282.         shift = i / 3;

  283.         mod   = i % 3;

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

  285.     }

  286. 

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

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

  289.         int n, norm;

  290.         n = i + 2;

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

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

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

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

  295.         av_dlog(NULL, "%d: norm=%x s=%x %x %x\n", i, norm,

  296.                 scale_factor_mult[i][0],

  297.                 scale_factor_mult[i][1],

  298.                 scale_factor_mult[i][2]);

  299.     }

  300. 

  301.     RENAME(ff_mpa_synth_init)(RENAME(ff_mpa_synth_window));

  302. 

  303.     /* huffman decode tables */

  304.     offset = 0;

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

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

  307.         int xsize, x, y;

  308.         uint8_t  tmp_bits [512] = { 0 };

  309.         uint16_t tmp_codes[512] = { 0 };

  310. 

  311.         xsize = h->xsize;

  312. 

  313.         j = 0;

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

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

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

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

  318.             }

  319.         }

  320. 

  321.         /* XXX: fail test */

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

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

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

  325.                  tmp_bits, 1, 1, tmp_codes, 2, 2,

  326.                  INIT_VLC_USE_NEW_STATIC);

  327.         offset += huff_vlc_tables_sizes[i];

  328.     }

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

  330. 

  331.     offset = 0;

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

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

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

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

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

  337.                  INIT_VLC_USE_NEW_STATIC);

  338.         offset += huff_quad_vlc_tables_sizes[i];

  339.     }

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

  341. 

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

  343.         k = 0;

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

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

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

  347.         }

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

  349.     }

  350. 

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

  352. 

  353.     mpegaudio_tableinit();

  354. 

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

  356.         if (ff_mpa_quant_bits[i] < 0) {

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

  358.                 int val1, val2, val3, steps;

  359.                 int val = j;

  360.                 steps   = ff_mpa_quant_steps[i];

  361.                 val1    = val % steps;

  362.                 val    /= steps;

  363.                 val2    = val % steps;

  364.                 val3    = val / steps;

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

  366.             }

  367.         }

  368.     }

  369. 

  370. 

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

  372.         float f;

  373.         INTFLOAT v;

  374.         if (i != 6) {

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

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

  377.         } else {

  378.             v = FIXR(1.0);

  379.         }

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

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

  382.     }

  383.     /* invalid values */

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

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

  386. 

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

  388.         double f;

  389.         int e, k;

  390. 

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

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

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

  394.             k = i & 1;

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

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

  397.             av_dlog(NULL, "is_table_lsf %d %d: %f %f\n",

  398.                     i, j, (float) is_table_lsf[j][0][i],

  399.                     (float) is_table_lsf[j][1][i]);

  400.         }

  401.     }

  402. 

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

  404.         float ci, cs, ca;

  405.         ci = ci_table[i];

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

  407.         ca = cs * ci;

  408. #if !CONFIG_FLOAT

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

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

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

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

  413. #else

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

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

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

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

  418. #endif

  419.     }

  420. }

  421. 

  422. static av_cold int decode_init(AVCodecContext * avctx)

  423. {

  424.     static int initialized_tables = 0;

  425.     MPADecodeContext *s = avctx->priv_data;

  426. 

  427.     if (!initialized_tables) {

  428.         decode_init_static();

  429.         initialized_tables = 1;

  430.     }

  431. 

  432.     s->avctx = avctx;

  433. 

  434.     ff_mpadsp_init(&s->mpadsp);

  435.     ff_dsputil_init(&s->dsp, avctx);

  436. 

  437.     avctx->sample_fmt= OUT_FMT;

  438.     s->err_recognition = avctx->err_recognition;

  439. 

  440.     if (avctx->codec_id == AV_CODEC_ID_MP3ADU)

  441.         s->adu_mode = 1;

  442. 

  443.     avcodec_get_frame_defaults(&s->frame);

  444.     avctx->coded_frame = &s->frame;

  445. 

  446.     return 0;

  447. }

  448. 

  449. #define C3 FIXHR(0.86602540378443864676/2)

  450. #define C4 FIXHR(0.70710678118654752439/2) //0.5 / cos(pi*(9)/36)

  451. #define C5 FIXHR(0.51763809020504152469/2) //0.5 / cos(pi*(5)/36)

  452. #define C6 FIXHR(1.93185165257813657349/4) //0.5 / cos(pi*(15)/36)

  453. 

  454. /* 12 points IMDCT. We compute it "by hand" by factorizing obvious

  455.    cases. */

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

  457. {

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

  459. 

  460.     in0  = in[0*3];

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

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

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

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

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

  466.     in5 += in3;

  467.     in3 += in1;

  468. 

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

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

  471. 

  472.     t1   = in0 - in4;

  473.     t2   = MULH3(in1 - in5, C4, 2);

  474. 

  475.     out[ 7] =

  476.     out[10] = t1 + t2;

  477.     out[ 1] =

  478.     out[ 4] = t1 - t2;

  479. 

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

  481.     in4     = in0 + in2;

  482.     in5    += 2*in1;

  483.     in1     = MULH3(in5 + in3, C5, 1);

  484.     out[ 8] =

  485.     out[ 9] = in4 + in1;

  486.     out[ 2] =

  487.     out[ 3] = in4 - in1;

  488. 

  489.     in0    -= in2;

  490.     in5     = MULH3(in5 - in3, C6, 2);

  491.     out[ 0] =

  492.     out[ 5] = in0 - in5;

  493.     out[ 6] =

  494.     out[11] = in0 + in5;

  495. }

  496. 

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

  498. static int mp_decode_layer1(MPADecodeContext *s)

  499. {

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

  501.     uint8_t allocation[MPA_MAX_CHANNELS][SBLIMIT];

  502.     uint8_t scale_factors[MPA_MAX_CHANNELS][SBLIMIT];

  503. 

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

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

  506.     else

  507.         bound = SBLIMIT;

  508. 

  509.     /* allocation bits */

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

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

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

  513.         }

  514.     }

  515.     for (i = bound; i < SBLIMIT; i++)

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

  517. 

  518.     /* scale factors */

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

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

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

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

  523.         }

  524.     }

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

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

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

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

  529.         }

  530.     }

  531. 

  532.     /* compute samples */

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

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

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

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

  537.                 if (n) {

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

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

  540.                 } else {

  541.                     v = 0;

  542.                 }

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

  544.             }

  545.         }

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

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

  548.             if (n) {

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

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

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

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

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

  554.             } else {

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

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

  557.             }

  558.         }

  559.     }

  560.     return 12;

  561. }

  562. 

  563. static int mp_decode_layer2(MPADecodeContext *s)

  564. {

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

  566.     const unsigned char *alloc_table;

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

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

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

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

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

  572. 

  573.     /* select decoding table */

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

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

  576.     sblimit     = ff_mpa_sblimit_table[table];

  577.     alloc_table = ff_mpa_alloc_tables[table];

  578. 

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

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

  581.     else

  582.         bound = sblimit;

  583. 

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

  585. 

  586.     /* sanity check */

  587.     if (bound > sblimit)

  588.         bound = sblimit;

  589. 

  590.     /* parse bit allocation */

  591.     j = 0;

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

  593.         bit_alloc_bits = alloc_table[j];

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

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

  596.         j += 1 << bit_alloc_bits;

  597.     }

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

  599.         bit_alloc_bits = alloc_table[j];

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

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

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

  603.         j += 1 << bit_alloc_bits;

  604.     }

  605. 

  606.     /* scale codes */

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

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

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

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

  611.         }

  612.     }

  613. 

  614.     /* scale factors */

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

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

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

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

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

  620.                 default:

  621.                 case 0:

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

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

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

  625.                     break;

  626.                 case 2:

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

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

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

  630.                     break;

  631.                 case 1:

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

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

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

  635.                     break;

  636.                 case 3:

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

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

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

  640.                     break;

  641.                 }

  642.             }

  643.         }

  644.     }

  645. 

  646.     /* samples */

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

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

  649.             j = 0;

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

  651.                 bit_alloc_bits = alloc_table[j];

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

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

  654.                     if (b) {

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

  656.                         qindex = alloc_table[j+b];

  657.                         bits = ff_mpa_quant_bits[qindex];

  658.                         if (bits < 0) {

  659.                             int v2;

  660.                             /* 3 values at the same time */

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

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

  663.                             steps  = ff_mpa_quant_steps[qindex];

  664. 

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

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

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

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

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

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

  671.                         } else {

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

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

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

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

  676.                             }

  677.                         }

  678.                     } else {

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

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

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

  682.                     }

  683.                 }

  684.                 /* next subband in alloc table */

  685.                 j += 1 << bit_alloc_bits;

  686.             }

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

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

  689.                 bit_alloc_bits = alloc_table[j];

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

  691.                 if (b) {

  692.                     int mant, scale0, scale1;

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

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

  695.                     qindex = alloc_table[j+b];

  696.                     bits = ff_mpa_quant_bits[qindex];

  697.                     if (bits < 0) {

  698.                         /* 3 values at the same time */

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

  700.                         steps = ff_mpa_quant_steps[qindex];

  701.                         mant = v % steps;

  702.                         v = v / steps;

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

  704.                             l2_unscale_group(steps, mant, scale0);

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

  706.                             l2_unscale_group(steps, mant, scale1);

  707.                         mant = v % steps;

  708.                         v = v / steps;

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

  710.                             l2_unscale_group(steps, mant, scale0);

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

  712.                             l2_unscale_group(steps, mant, scale1);

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

  714.                             l2_unscale_group(steps, v, scale0);

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

  716.                             l2_unscale_group(steps, v, scale1);

  717.                     } else {

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

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

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

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

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

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

  724.                         }

  725.                     }

  726.                 } else {

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

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

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

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

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

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

  733.                 }

  734.                 /* next subband in alloc table */

  735.                 j += 1 << bit_alloc_bits;

  736.             }

  737.             /* fill remaining samples to zero */

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

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

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

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

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

  743.                 }

  744.             }

  745.         }

  746.     }

  747.     return 3 * 12;

  748. }

  749. 

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

  751.     if (n == 3) {                   \

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

  753.         dst   = sf - 3 * m;         \

  754.         sf    = m;                  \

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

  756.         dst  = sf & 3;              \

  757.         sf >>= 2;                   \

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

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

  760.         dst   = sf - 5 * m;         \

  761.         sf    = m;                  \

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

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

  764.         dst   = sf - 6 * m;         \

  765.         sf    = m;                  \

  766.     } else {                        \

  767.         dst = 0;                    \

  768.     }

  769. 

  770. static av_always_inline void lsf_sf_expand(int *slen, int sf, int n1, int n2,

  771.                                            int n3)

  772. {

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

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

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

  776.     slen[0] = sf;

  777. }

  778. 

  779. static void exponents_from_scale_factors(MPADecodeContext *s, GranuleDef *g,

  780.                                          int16_t *exponents)

  781. {

  782.     const uint8_t *bstab, *pretab;

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

  784.     int16_t *exp_ptr;

  785. 

  786.     exp_ptr = exponents;

  787.     gain    = g->global_gain - 210;

  788.     shift   = g->scalefac_scale + 1;

  789. 

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

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

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

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

  794.         len = bstab[i];

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

  796.             *exp_ptr++ = v0;

  797.     }

  798. 

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

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

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

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

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

  804.         k        = g->long_end;

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

  806.             len = bstab[i];

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

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

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

  810.                     *exp_ptr++ = v0;

  811.             }

  812.         }

  813.     }

  814. }

  815. 

  816. /* handle n = 0 too */

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

  818. {

  819.     return n ? get_bits(s, n) : 0;

  820. }

  821. 

  822. 

  823. static void switch_buffer(MPADecodeContext *s, int *pos, int *end_pos,

  824.                           int *end_pos2)

  825. {

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

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

  828.         s->in_gb.buffer = NULL;

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

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

  831.         *end_pos2 =

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

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

  834.     }

  835. }

  836. 

  837. /* Following is a optimized code for

  838.             INTFLOAT v = *src

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

  840.                 v = -v;

  841.             *dst = v;

  842. */

  843. #if CONFIG_FLOAT

  844. #define READ_FLIP_SIGN(dst,src)                     \

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

  846.     AV_WN32A(dst, v);

  847. #else

  848. #define READ_FLIP_SIGN(dst,src)     \

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

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

  851. #endif

  852. 

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

  854.                           int16_t *exponents, int end_pos2)

  855. {

  856.     int s_index;

  857.     int i;

  858.     int last_pos, bits_left;

  859.     VLC *vlc;

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

  861. 

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

  863.     s_index = 0;

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

  865.         int j, k, l, linbits;

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

  867.         if (j == 0)

  868.             continue;

  869.         /* select vlc table */

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

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

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

  873.         vlc     = &huff_vlc[l];

  874. 

  875.         if (!l) {

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

  877.             s_index += 2 * j;

  878.             continue;

  879.         }

  880. 

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

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

  883.             int exponent, x, y;

  884.             int v;

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

  886. 

  887.             if (pos >= end_pos){

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

  889.                 if (pos >= end_pos)

  890.                     break;

  891.             }

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

  893. 

  894.             if (!y) {

  895.                 g->sb_hybrid[s_index  ] =

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

  897.                 s_index += 2;

  898.                 continue;

  899.             }

  900. 

  901.             exponent= exponents[s_index];

  902. 

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

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

  905.             if (y & 16) {

  906.                 x = y >> 5;

  907.                 y = y & 0x0f;

  908.                 if (x < 15) {

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

  910.                 } else {

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

  912.                     v  = l3_unscale(x, exponent);

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

  914.                         v = -v;

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

  916.                 }

  917.                 if (y < 15) {

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

  919.                 } else {

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

  921.                     v  = l3_unscale(y, exponent);

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

  923.                         v = -v;

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

  925.                 }

  926.             } else {

  927.                 x = y >> 5;

  928.                 y = y & 0x0f;

  929.                 x += y;

  930.                 if (x < 15) {

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

  932.                 } else {

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

  934.                     v  = l3_unscale(x, exponent);

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

  936.                         v = -v;

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

  938.                 }

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

  940.             }

  941.             s_index += 2;

  942.         }

  943.     }

  944. 

  945.     /* high frequencies */

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

  947.     last_pos = 0;

  948.     while (s_index <= 572) {

  949.         int pos, code;

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

  951.         if (pos >= end_pos) {

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

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

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

  955.                 s_index -= 4;

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

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

  958.                 if(s->err_recognition & AV_EF_BITSTREAM)

  959.                     s_index=0;

  960.                 break;

  961.             }

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

  963.             if (pos >= end_pos)

  964.                 break;

  965.         }

  966.         last_pos = pos;

  967. 

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

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

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

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

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

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

  974.         while (code) {

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

  976.             int v;

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

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

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

  980.         }

  981.         s_index += 4;

  982.     }

  983.     /* skip extension bits */

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

  985.     if (bits_left < 0 && (s->err_recognition & AV_EF_BUFFER)) {

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

  987.         s_index=0;

  988.     } else if (bits_left > 0 && (s->err_recognition & AV_EF_BUFFER)) {

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

  990.         s_index = 0;

  991.     }

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

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

  994. 

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

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

  997. 

  998.     return 0;

  999. }

  1000. 

  1001. /* Reorder short blocks from bitstream order to interleaved order. It

  1002.    would be faster to do it in parsing, but the code would be far more

  1003.    complicated */

  1004. static void reorder_block(MPADecodeContext *s, GranuleDef *g)

  1005. {

  1006.     int i, j, len;

  1007.     INTFLOAT *ptr, *dst, *ptr1;

  1008.     INTFLOAT tmp[576];

  1009. 

  1010.     if (g->block_type != 2)

  1011.         return;

  1012. 

  1013.     if (g->switch_point) {

  1014.         if (s->sample_rate_index != 8)

  1015.             ptr = g->sb_hybrid + 36;

  1016.         else

  1017.             ptr = g->sb_hybrid + 72;

  1018.     } else {

  1019.         ptr = g->sb_hybrid;

  1020.     }

  1021. 

  1022.     for (i = g->short_start; i < 13; i++) {

  1023.         len  = band_size_short[s->sample_rate_index][i];

  1024.         ptr1 = ptr;

  1025.         dst  = tmp;

  1026.         for (j = len; j > 0; j--) {

  1027.             *dst++ = ptr[0*len];

  1028.             *dst++ = ptr[1*len];

  1029.             *dst++ = ptr[2*len];

  1030.             ptr++;

  1031.         }

  1032.         ptr += 2 * len;

  1033.         memcpy(ptr1, tmp, len * 3 * sizeof(*ptr1));

  1034.     }

  1035. }

  1036. 

  1037. #define ISQRT2 FIXR(0.70710678118654752440)

  1038. 

  1039. static void compute_stereo(MPADecodeContext *s, GranuleDef *g0, GranuleDef *g1)

  1040. {

  1041.     int i, j, k, l;

  1042.     int sf_max, sf, len, non_zero_found;

  1043.     INTFLOAT (*is_tab)[16], *tab0, *tab1, tmp0, tmp1, v1, v2;

  1044.     int non_zero_found_short[3];

  1045. 

  1046.     /* intensity stereo */

  1047.     if (s->mode_ext & MODE_EXT_I_STEREO) {

  1048.         if (!s->lsf) {

  1049.             is_tab = is_table;

  1050.             sf_max = 7;

  1051.         } else {

  1052.             is_tab = is_table_lsf[g1->scalefac_compress & 1];

  1053.             sf_max = 16;

  1054.         }

  1055. 

  1056.         tab0 = g0->sb_hybrid + 576;

  1057.         tab1 = g1->sb_hybrid + 576;

  1058. 

  1059.         non_zero_found_short[0] = 0;

  1060.         non_zero_found_short[1] = 0;

  1061.         non_zero_found_short[2] = 0;

  1062.         k = (13 - g1->short_start) * 3 + g1->long_end - 3;

  1063.         for (i = 12; i >= g1->short_start; i--) {

  1064.             /* for last band, use previous scale factor */

  1065.             if (i != 11)

  1066.                 k -= 3;

  1067.             len = band_size_short[s->sample_rate_index][i];

  1068.             for (l = 2; l >= 0; l--) {

  1069.                 tab0 -= len;

  1070.                 tab1 -= len;

  1071.                 if (!non_zero_found_short[l]) {

  1072.                     /* test if non zero band. if so, stop doing i-stereo */

  1073.                     for (j = 0; j < len; j++) {

  1074.                         if (tab1[j] != 0) {

  1075.                             non_zero_found_short[l] = 1;

  1076.                             goto found1;

  1077.                         }

  1078.                     }

  1079.                     sf = g1->scale_factors[k + l];

  1080.                     if (sf >= sf_max)

  1081.                         goto found1;

  1082. 

  1083.                     v1 = is_tab[0][sf];

  1084.                     v2 = is_tab[1][sf];

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

  1086.                         tmp0    = tab0[j];

  1087.                         tab0[j] = MULLx(tmp0, v1, FRAC_BITS);

  1088.                         tab1[j] = MULLx(tmp0, v2, FRAC_BITS);

  1089.                     }

  1090.                 } else {

  1091. found1:

  1092.                     if (s->mode_ext & MODE_EXT_MS_STEREO) {

  1093.                         /* lower part of the spectrum : do ms stereo

  1094.                            if enabled */

  1095.                         for (j = 0; j < len; j++) {

  1096.                             tmp0    = tab0[j];

  1097.                             tmp1    = tab1[j];

  1098.                             tab0[j] = MULLx(tmp0 + tmp1, ISQRT2, FRAC_BITS);

  1099.                             tab1[j] = MULLx(tmp0 - tmp1, ISQRT2, FRAC_BITS);

  1100.                         }

  1101.                     }

  1102.                 }

  1103.             }

  1104.         }

  1105. 

  1106.         non_zero_found = non_zero_found_short[0] |

  1107.                          non_zero_found_short[1] |

  1108.                          non_zero_found_short[2];

  1109. 

  1110.         for (i = g1->long_end - 1;i >= 0;i--) {

  1111.             len   = band_size_long[s->sample_rate_index][i];

  1112.             tab0 -= len;

  1113.             tab1 -= len;

  1114.             /* test if non zero band. if so, stop doing i-stereo */

  1115.             if (!non_zero_found) {

  1116.                 for (j = 0; j < len; j++) {

  1117.                     if (tab1[j] != 0) {

  1118.                         non_zero_found = 1;

  1119.                         goto found2;

  1120.                     }

  1121.                 }

  1122.                 /* for last band, use previous scale factor */

  1123.                 k  = (i == 21) ? 20 : i;

  1124.                 sf = g1->scale_factors[k];

  1125.                 if (sf >= sf_max)

  1126.                     goto found2;

  1127.                 v1 = is_tab[0][sf];

  1128.                 v2 = is_tab[1][sf];

  1129.                 for (j = 0; j < len; j++) {

  1130.                     tmp0    = tab0[j];

  1131.                     tab0[j] = MULLx(tmp0, v1, FRAC_BITS);

  1132.                     tab1[j] = MULLx(tmp0, v2, FRAC_BITS);

  1133.                 }

  1134.             } else {

  1135. found2:

  1136.                 if (s->mode_ext & MODE_EXT_MS_STEREO) {

  1137.                     /* lower part of the spectrum : do ms stereo

  1138.                        if enabled */

  1139.                     for (j = 0; j < len; j++) {

  1140.                         tmp0    = tab0[j];

  1141.                         tmp1    = tab1[j];

  1142.                         tab0[j] = MULLx(tmp0 + tmp1, ISQRT2, FRAC_BITS);

  1143.                         tab1[j] = MULLx(tmp0 - tmp1, ISQRT2, FRAC_BITS);

  1144.                     }

  1145.                 }

  1146.             }

  1147.         }

  1148.     } else if (s->mode_ext & MODE_EXT_MS_STEREO) {

  1149.         /* ms stereo ONLY */

  1150.         /* NOTE: the 1/sqrt(2) normalization factor is included in the

  1151.            global gain */

  1152. #if CONFIG_FLOAT

  1153.        s-> dsp.butterflies_float(g0->sb_hybrid, g1->sb_hybrid, 576);

  1154. #else

  1155.         tab0 = g0->sb_hybrid;

  1156.         tab1 = g1->sb_hybrid;

  1157.         for (i = 0; i < 576; i++) {

  1158.             tmp0    = tab0[i];

  1159.             tmp1    = tab1[i];

  1160.             tab0[i] = tmp0 + tmp1;

  1161.             tab1[i] = tmp0 - tmp1;

  1162.         }

  1163. #endif

  1164.     }

  1165. }

  1166. 

  1167. #if CONFIG_FLOAT

  1168. #define AA(j) do {                                                      \

  1169.         float tmp0 = ptr[-1-j];                                         \

  1170.         float tmp1 = ptr[   j];                                         \

  1171.         ptr[-1-j] = tmp0 * csa_table[j][0] - tmp1 * csa_table[j][1];    \

  1172.         ptr[   j] = tmp0 * csa_table[j][1] + tmp1 * csa_table[j][0];    \

  1173.     } while (0)

  1174. #else

  1175. #define AA(j) do {                                              \

  1176.         int tmp0 = ptr[-1-j];                                   \

  1177.         int tmp1 = ptr[   j];                                   \

  1178.         int tmp2 = MULH(tmp0 + tmp1, csa_table[j][0]);          \

  1179.         ptr[-1-j] = 4 * (tmp2 - MULH(tmp1, csa_table[j][2]));   \

  1180.         ptr[   j] = 4 * (tmp2 + MULH(tmp0, csa_table[j][3]));   \

  1181.     } while (0)

  1182. #endif

  1183. 

  1184. static void compute_antialias(MPADecodeContext *s, GranuleDef *g)

  1185. {

  1186.     INTFLOAT *ptr;

  1187.     int n, i;

  1188. 

  1189.     /* we antialias only "long" bands */

  1190.     if (g->block_type == 2) {

  1191.         if (!g->switch_point)

  1192.             return;

  1193.         /* XXX: check this for 8000Hz case */

  1194.         n = 1;

  1195.     } else {

  1196.         n = SBLIMIT - 1;

  1197.     }

  1198. 

  1199.     ptr = g->sb_hybrid + 18;

  1200.     for (i = n; i > 0; i--) {

  1201.         AA(0);

  1202.         AA(1);

  1203.         AA(2);

  1204.         AA(3);

  1205.         AA(4);

  1206.         AA(5);

  1207.         AA(6);

  1208.         AA(7);

  1209. 

  1210.         ptr += 18;

  1211.     }

  1212. }

  1213. 

  1214. static void compute_imdct(MPADecodeContext *s, GranuleDef *g,

  1215.                           INTFLOAT *sb_samples, INTFLOAT *mdct_buf)

  1216. {

  1217.     INTFLOAT *win, *out_ptr, *ptr, *buf, *ptr1;

  1218.     INTFLOAT out2[12];

  1219.     int i, j, mdct_long_end, sblimit;

  1220. 

  1221.     /* find last non zero block */

  1222.     ptr  = g->sb_hybrid + 576;

  1223.     ptr1 = g->sb_hybrid + 2 * 18;

  1224.     while (ptr >= ptr1) {

  1225.         int32_t *p;

  1226.         ptr -= 6;

  1227.         p    = (int32_t*)ptr;

  1228.         if (p[0] | p[1] | p[2] | p[3] | p[4] | p[5])

  1229.             break;

  1230.     }

  1231.     sblimit = ((ptr - g->sb_hybrid) / 18) + 1;

  1232. 

  1233.     if (g->block_type == 2) {

  1234.         /* XXX: check for 8000 Hz */

  1235.         if (g->switch_point)

  1236.             mdct_long_end = 2;

  1237.         else

  1238.             mdct_long_end = 0;

  1239.     } else {

  1240.         mdct_long_end = sblimit;

  1241.     }

  1242. 

  1243.     s->mpadsp.RENAME(imdct36_blocks)(sb_samples, mdct_buf, g->sb_hybrid,

  1244.                                      mdct_long_end, g->switch_point,

  1245.                                      g->block_type);

  1246. 

  1247.     buf = mdct_buf + 4*18*(mdct_long_end >> 2) + (mdct_long_end & 3);

  1248.     ptr = g->sb_hybrid + 18 * mdct_long_end;

  1249. 

  1250.     for (j = mdct_long_end; j < sblimit; j++) {

  1251.         /* select frequency inversion */

  1252.         win     = RENAME(ff_mdct_win)[2 + (4  & -(j & 1))];

  1253.         out_ptr = sb_samples + j;

  1254. 

  1255.         for (i = 0; i < 6; i++) {

  1256.             *out_ptr = buf[4*i];

  1257.             out_ptr += SBLIMIT;

  1258.         }

  1259.         imdct12(out2, ptr + 0);

  1260.         for (i = 0; i < 6; i++) {

  1261.             *out_ptr     = MULH3(out2[i    ], win[i    ], 1) + buf[4*(i + 6*1)];

  1262.             buf[4*(i + 6*2)] = MULH3(out2[i + 6], win[i + 6], 1);

  1263.             out_ptr += SBLIMIT;

  1264.         }

  1265.         imdct12(out2, ptr + 1);

  1266.         for (i = 0; i < 6; i++) {

  1267.             *out_ptr     = MULH3(out2[i    ], win[i    ], 1) + buf[4*(i + 6*2)];

  1268.             buf[4*(i + 6*0)] = MULH3(out2[i + 6], win[i + 6], 1);

  1269.             out_ptr += SBLIMIT;

  1270.         }

  1271.         imdct12(out2, ptr + 2);

  1272.         for (i = 0; i < 6; i++) {

  1273.             buf[4*(i + 6*0)] = MULH3(out2[i    ], win[i    ], 1) + buf[4*(i + 6*0)];

  1274.             buf[4*(i + 6*1)] = MULH3(out2[i + 6], win[i + 6], 1);

  1275.             buf[4*(i + 6*2)] = 0;

  1276.         }

  1277.         ptr += 18;

  1278.         buf += (j&3) != 3 ? 1 : (4*18-3);

  1279.     }

  1280.     /* zero bands */

  1281.     for (j = sblimit; j < SBLIMIT; j++) {

  1282.         /* overlap */

  1283.         out_ptr = sb_samples + j;

  1284.         for (i = 0; i < 18; i++) {

  1285.             *out_ptr = buf[4*i];

  1286.             buf[4*i]   = 0;

  1287.             out_ptr += SBLIMIT;

  1288.         }

  1289.         buf += (j&3) != 3 ? 1 : (4*18-3);

  1290.     }

  1291. }

  1292. 

  1293. /* main layer3 decoding function */

  1294. static int mp_decode_layer3(MPADecodeContext *s)

  1295. {

  1296.     int nb_granules, main_data_begin;

  1297.     int gr, ch, blocksplit_flag, i, j, k, n, bits_pos;

  1298.     GranuleDef *g;

  1299.     int16_t exponents[576]; //FIXME try INTFLOAT

  1300. 

  1301.     /* read side info */

  1302.     if (s->lsf) {

  1303.         main_data_begin = get_bits(&s->gb, 8);

  1304.         skip_bits(&s->gb, s->nb_channels);

  1305.         nb_granules = 1;

  1306.     } else {

  1307.         main_data_begin = get_bits(&s->gb, 9);

  1308.         if (s->nb_channels == 2)

  1309.             skip_bits(&s->gb, 3);

  1310.         else

  1311.             skip_bits(&s->gb, 5);

  1312.         nb_granules = 2;

  1313.         for (ch = 0; ch < s->nb_channels; ch++) {

  1314.             s->granules[ch][0].scfsi = 0;/* all scale factors are transmitted */

  1315.             s->granules[ch][1].scfsi = get_bits(&s->gb, 4);

  1316.         }

  1317.     }

  1318. 

  1319.     for (gr = 0; gr < nb_granules; gr++) {

  1320.         for (ch = 0; ch < s->nb_channels; ch++) {

  1321.             av_dlog(s->avctx, "gr=%d ch=%d: side_info\n", gr, ch);

  1322.             g = &s->granules[ch][gr];

  1323.             g->part2_3_length = get_bits(&s->gb, 12);

  1324.             g->big_values     = get_bits(&s->gb,  9);

  1325.             if (g->big_values > 288) {

  1326.                 av_log(s->avctx, AV_LOG_ERROR, "big_values too big\n");

  1327.                 return AVERROR_INVALIDDATA;

  1328.             }

  1329. 

  1330.             g->global_gain = get_bits(&s->gb, 8);

  1331.             /* if MS stereo only is selected, we precompute the

  1332.                1/sqrt(2) renormalization factor */

  1333.             if ((s->mode_ext & (MODE_EXT_MS_STEREO | MODE_EXT_I_STEREO)) ==

  1334.                 MODE_EXT_MS_STEREO)

  1335.                 g->global_gain -= 2;

  1336.             if (s->lsf)

  1337.                 g->scalefac_compress = get_bits(&s->gb, 9);

  1338.             else

  1339.                 g->scalefac_compress = get_bits(&s->gb, 4);

  1340.             blocksplit_flag = get_bits1(&s->gb);

  1341.             if (blocksplit_flag) {

  1342.                 g->block_type = get_bits(&s->gb, 2);

  1343.                 if (g->block_type == 0) {

  1344.                     av_log(s->avctx, AV_LOG_ERROR, "invalid block type\n");

  1345.                     return AVERROR_INVALIDDATA;

  1346.                 }

  1347.                 g->switch_point = get_bits1(&s->gb);

  1348.                 for (i = 0; i < 2; i++)

  1349.                     g->table_select[i] = get_bits(&s->gb, 5);

  1350.                 for (i = 0; i < 3; i++)

  1351.                     g->subblock_gain[i] = get_bits(&s->gb, 3);

  1352.                 ff_init_short_region(s, g);

  1353.             } else {

  1354.                 int region_address1, region_address2;

  1355.                 g->block_type = 0;

  1356.                 g->switch_point = 0;

  1357.                 for (i = 0; i < 3; i++)

  1358.                     g->table_select[i] = get_bits(&s->gb, 5);

  1359.                 /* compute huffman coded region sizes */

  1360.                 region_address1 = get_bits(&s->gb, 4);

  1361.                 region_address2 = get_bits(&s->gb, 3);

  1362.                 av_dlog(s->avctx, "region1=%d region2=%d\n",

  1363.                         region_address1, region_address2);

  1364.                 ff_init_long_region(s, g, region_address1, region_address2);

  1365.             }

  1366.             ff_region_offset2size(g);

  1367.             ff_compute_band_indexes(s, g);

  1368. 

  1369.             g->preflag = 0;

  1370.             if (!s->lsf)

  1371.                 g->preflag = get_bits1(&s->gb);

  1372.             g->scalefac_scale     = get_bits1(&s->gb);

  1373.             g->count1table_select = get_bits1(&s->gb);

  1374.             av_dlog(s->avctx, "block_type=%d switch_point=%d\n",

  1375.                     g->block_type, g->switch_point);

  1376.         }

  1377.     }

  1378. 

  1379.     if (!s->adu_mode) {

  1380.         int skip;

  1381.         const uint8_t *ptr = s->gb.buffer + (get_bits_count(&s->gb)>>3);

  1382.         int extrasize = av_clip(get_bits_left(&s->gb) >> 3, 0,

  1383.                                 FFMAX(0, LAST_BUF_SIZE - s->last_buf_size));

  1384.         assert((get_bits_count(&s->gb) & 7) == 0);

  1385.         /* now we get bits from the main_data_begin offset */

  1386.         av_dlog(s->avctx, "seekback:%d, lastbuf:%d\n",

  1387.                 main_data_begin, s->last_buf_size);

  1388. 

  1389.         memcpy(s->last_buf + s->last_buf_size, ptr, extrasize);

  1390.         s->in_gb = s->gb;

  1391.         init_get_bits(&s->gb, s->last_buf, s->last_buf_size*8);

  1392. #if !UNCHECKED_BITSTREAM_READER

  1393.         s->gb.size_in_bits_plus8 += extrasize * 8;

  1394. #endif

  1395.         s->last_buf_size <<= 3;

  1396.         for (gr = 0; gr < nb_granules && (s->last_buf_size >> 3) < main_data_begin; gr++) {

  1397.             for (ch = 0; ch < s->nb_channels; ch++) {

  1398.                 g = &s->granules[ch][gr];

  1399.                 s->last_buf_size += g->part2_3_length;

  1400.                 memset(g->sb_hybrid, 0, sizeof(g->sb_hybrid));

  1401.                 compute_imdct(s, g, &s->sb_samples[ch][18 * gr][0], s->mdct_buf[ch]);

  1402.             }

  1403.         }

  1404.         skip = s->last_buf_size - 8 * main_data_begin;

  1405.         if (skip >= s->gb.size_in_bits && s->in_gb.buffer) {

  1406.             skip_bits_long(&s->in_gb, skip - s->gb.size_in_bits);

  1407.             s->gb           = s->in_gb;

  1408.             s->in_gb.buffer = NULL;

  1409.         } else {

  1410.             skip_bits_long(&s->gb, skip);

  1411.         }

  1412.     } else {

  1413.         gr = 0;

  1414.     }

  1415. 

  1416.     for (; gr < nb_granules; gr++) {

  1417.         for (ch = 0; ch < s->nb_channels; ch++) {

  1418.             g = &s->granules[ch][gr];

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

  1420. 

  1421.             if (!s->lsf) {

  1422.                 uint8_t *sc;

  1423.                 int slen, slen1, slen2;

  1424. 

  1425.                 /* MPEG1 scale factors */

  1426.                 slen1 = slen_table[0][g->scalefac_compress];

  1427.                 slen2 = slen_table[1][g->scalefac_compress];

  1428.                 av_dlog(s->avctx, "slen1=%d slen2=%d\n", slen1, slen2);

  1429.                 if (g->block_type == 2) {

  1430.                     n = g->switch_point ? 17 : 18;

  1431.                     j = 0;

  1432.                     if (slen1) {

  1433.                         for (i = 0; i < n; i++)

  1434.                             g->scale_factors[j++] = get_bits(&s->gb, slen1);

  1435.                     } else {

  1436.                         for (i = 0; i < n; i++)

  1437.                             g->scale_factors[j++] = 0;

  1438.                     }

  1439.                     if (slen2) {

  1440.                         for (i = 0; i < 18; i++)

  1441.                             g->scale_factors[j++] = get_bits(&s->gb, slen2);

  1442.                         for (i = 0; i < 3; i++)

  1443.                             g->scale_factors[j++] = 0;

  1444.                     } else {

  1445.                         for (i = 0; i < 21; i++)

  1446.                             g->scale_factors[j++] = 0;

  1447.                     }

  1448.                 } else {

  1449.                     sc = s->granules[ch][0].scale_factors;

  1450.                     j = 0;

  1451.                     for (k = 0; k < 4; k++) {

  1452.                         n = k == 0 ? 6 : 5;

  1453.                         if ((g->scfsi & (0x8 >> k)) == 0) {

  1454.                             slen = (k < 2) ? slen1 : slen2;

  1455.                             if (slen) {

  1456.                                 for (i = 0; i < n; i++)

  1457.                                     g->scale_factors[j++] = get_bits(&s->gb, slen);

  1458.                             } else {

  1459.                                 for (i = 0; i < n; i++)

  1460.                                     g->scale_factors[j++] = 0;

  1461.                             }

  1462.                         } else {

  1463.                             /* simply copy from last granule */

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

  1465.                                 g->scale_factors[j] = sc[j];

  1466.                                 j++;

  1467.                             }

  1468.                         }

  1469.                     }

  1470.                     g->scale_factors[j++] = 0;

  1471.                 }

  1472.             } else {

  1473.                 int tindex, tindex2, slen[4], sl, sf;

  1474. 

  1475.                 /* LSF scale factors */

  1476.                 if (g->block_type == 2)

  1477.                     tindex = g->switch_point ? 2 : 1;

  1478.                 else

  1479.                     tindex = 0;

  1480. 

  1481.                 sf = g->scalefac_compress;

  1482.                 if ((s->mode_ext & MODE_EXT_I_STEREO) && ch == 1) {

  1483.                     /* intensity stereo case */

  1484.                     sf >>= 1;

  1485.                     if (sf < 180) {

  1486.                         lsf_sf_expand(slen, sf, 6, 6, 0);

  1487.                         tindex2 = 3;

  1488.                     } else if (sf < 244) {

  1489.                         lsf_sf_expand(slen, sf - 180, 4, 4, 0);

  1490.                         tindex2 = 4;

  1491.                     } else {

  1492.                         lsf_sf_expand(slen, sf - 244, 3, 0, 0);

  1493.                         tindex2 = 5;

  1494.                     }

  1495.                 } else {

  1496.                     /* normal case */

  1497.                     if (sf < 400) {

  1498.                         lsf_sf_expand(slen, sf, 5, 4, 4);

  1499.                         tindex2 = 0;

  1500.                     } else if (sf < 500) {

  1501.                         lsf_sf_expand(slen, sf - 400, 5, 4, 0);

  1502.                         tindex2 = 1;

  1503.                     } else {

  1504.                         lsf_sf_expand(slen, sf - 500, 3, 0, 0);

  1505.                         tindex2 = 2;

  1506.                         g->preflag = 1;

  1507.                     }

  1508.                 }

  1509. 

  1510.                 j = 0;

  1511.                 for (k = 0; k < 4; k++) {

  1512.                     n  = lsf_nsf_table[tindex2][tindex][k];

  1513.                     sl = slen[k];

  1514.                     if (sl) {

  1515.                         for (i = 0; i < n; i++)

  1516.                             g->scale_factors[j++] = get_bits(&s->gb, sl);

  1517.                     } else {

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

  1519.                             g->scale_factors[j++] = 0;

  1520.                     }

  1521.                 }

  1522.                 /* XXX: should compute exact size */

  1523.                 for (; j < 40; j++)

  1524.                     g->scale_factors[j] = 0;

  1525.             }

  1526. 

  1527.             exponents_from_scale_factors(s, g, exponents);

  1528. 

  1529.             /* read Huffman coded residue */

  1530.             huffman_decode(s, g, exponents, bits_pos + g->part2_3_length);

  1531.         } /* ch */

  1532. 

  1533.         if (s->mode == MPA_JSTEREO)

  1534.             compute_stereo(s, &s->granules[0][gr], &s->granules[1][gr]);

  1535. 

  1536.         for (ch = 0; ch < s->nb_channels; ch++) {

  1537.             g = &s->granules[ch][gr];

  1538. 

  1539.             reorder_block(s, g);

  1540.             compute_antialias(s, g);

  1541.             compute_imdct(s, g, &s->sb_samples[ch][18 * gr][0], s->mdct_buf[ch]);

  1542.         }

  1543.     } /* gr */

  1544.     if (get_bits_count(&s->gb) < 0)

  1545.         skip_bits_long(&s->gb, -get_bits_count(&s->gb));

  1546.     return nb_granules * 18;

  1547. }

  1548. 

  1549. static int mp_decode_frame(MPADecodeContext *s, OUT_INT *samples,

  1550.                            const uint8_t *buf, int buf_size)

  1551. {

  1552.     int i, nb_frames, ch, ret;

  1553.     OUT_INT *samples_ptr;

  1554. 

  1555.     init_get_bits(&s->gb, buf + HEADER_SIZE, (buf_size - HEADER_SIZE) * 8);

  1556. 

  1557.     /* skip error protection field */

  1558.     if (s->error_protection)

  1559.         skip_bits(&s->gb, 16);

  1560. 

  1561.     switch(s->layer) {

  1562.     case 1:

  1563.         s->avctx->frame_size = 384;

  1564.         nb_frames = mp_decode_layer1(s);

  1565.         break;

  1566.     case 2:

  1567.         s->avctx->frame_size = 1152;

  1568.         nb_frames = mp_decode_layer2(s);

  1569.         break;

  1570.     case 3:

  1571.         s->avctx->frame_size = s->lsf ? 576 : 1152;

  1572.     default:

  1573.         nb_frames = mp_decode_layer3(s);

  1574. 

  1575.         if (nb_frames < 0)

  1576.             return nb_frames;

  1577. 

  1578.         s->last_buf_size=0;

  1579.         if (s->in_gb.buffer) {

  1580.             align_get_bits(&s->gb);

  1581.             i = get_bits_left(&s->gb)>>3;

  1582.             if (i >= 0 && i <= BACKSTEP_SIZE) {

  1583.                 memmove(s->last_buf, s->gb.buffer + (get_bits_count(&s->gb)>>3), i);

  1584.                 s->last_buf_size=i;

  1585.             } else

  1586.                 av_log(s->avctx, AV_LOG_ERROR, "invalid old backstep %d\n", i);

  1587.             s->gb           = s->in_gb;

  1588.             s->in_gb.buffer = NULL;

  1589.         }

  1590. 

  1591.         align_get_bits(&s->gb);

  1592.         assert((get_bits_count(&s->gb) & 7) == 0);

  1593.         i = get_bits_left(&s->gb) >> 3;

  1594. 

  1595.         if (i < 0 || i > BACKSTEP_SIZE || nb_frames < 0) {

  1596.             if (i < 0)

  1597.                 av_log(s->avctx, AV_LOG_ERROR, "invalid new backstep %d\n", i);

  1598.             i = FFMIN(BACKSTEP_SIZE, buf_size - HEADER_SIZE);

  1599.         }

  1600.         assert(i <= buf_size - HEADER_SIZE && i >= 0);

  1601.         memcpy(s->last_buf + s->last_buf_size, s->gb.buffer + buf_size - HEADER_SIZE - i, i);

  1602.         s->last_buf_size += i;

  1603.     }

  1604. 

  1605.     /* get output buffer */

  1606.     if (!samples) {

  1607.         s->frame.nb_samples = s->avctx->frame_size;

  1608.         if ((ret = s->avctx->get_buffer(s->avctx, &s->frame)) < 0) {

  1609.             av_log(s->avctx, AV_LOG_ERROR, "get_buffer() failed\n");

  1610.             return ret;

  1611.         }

  1612.         samples = (OUT_INT *)s->frame.data[0];

  1613.     }

  1614. 

  1615.     /* apply the synthesis filter */

  1616.     for (ch = 0; ch < s->nb_channels; ch++) {

  1617.         samples_ptr = samples + ch;

  1618.         for (i = 0; i < nb_frames; i++) {

  1619.             RENAME(ff_mpa_synth_filter)(

  1620.                          &s->mpadsp,

  1621.                          s->synth_buf[ch], &(s->synth_buf_offset[ch]),

  1622.                          RENAME(ff_mpa_synth_window), &s->dither_state,

  1623.                          samples_ptr, s->nb_channels,

  1624.                          s->sb_samples[ch][i]);

  1625.             samples_ptr += 32 * s->nb_channels;

  1626.         }

  1627.     }

  1628. 

  1629.     return nb_frames * 32 * sizeof(OUT_INT) * s->nb_channels;

  1630. }

  1631. 

  1632. static int decode_frame(AVCodecContext * avctx, void *data, int *got_frame_ptr,

  1633.                         AVPacket *avpkt)

  1634. {

  1635.     const uint8_t *buf  = avpkt->data;

  1636.     int buf_size        = avpkt->size;

  1637.     MPADecodeContext *s = avctx->priv_data;

  1638.     uint32_t header;

  1639.     int ret;

  1640. 

  1641.     if (buf_size < HEADER_SIZE)

  1642.         return AVERROR_INVALIDDATA;

  1643. 

  1644.     header = AV_RB32(buf);

  1645.     if (ff_mpa_check_header(header) < 0) {

  1646.         av_log(avctx, AV_LOG_ERROR, "Header missing\n");

  1647.         return AVERROR_INVALIDDATA;

  1648.     }

  1649. 

  1650.     if (avpriv_mpegaudio_decode_header((MPADecodeHeader *)s, header) == 1) {

  1651.         /* free format: prepare to compute frame size */

  1652.         s->frame_size = -1;

  1653.         return AVERROR_INVALIDDATA;

  1654.     }

  1655.     /* update codec info */

  1656.     avctx->channels       = s->nb_channels;

  1657.     avctx->channel_layout = s->nb_channels == 1 ? AV_CH_LAYOUT_MONO : AV_CH_LAYOUT_STEREO;

  1658.     if (!avctx->bit_rate)

  1659.         avctx->bit_rate = s->bit_rate;

  1660. 

  1661.     if (s->frame_size <= 0 || s->frame_size > buf_size) {

  1662.         av_log(avctx, AV_LOG_ERROR, "incomplete frame\n");

  1663.         return AVERROR_INVALIDDATA;

  1664.     } else if (s->frame_size < buf_size) {

  1665.         buf_size= s->frame_size;

  1666.     }

  1667. 

  1668.     ret = mp_decode_frame(s, NULL, buf, buf_size);

  1669.     if (ret >= 0) {

  1670.         *got_frame_ptr   = 1;

  1671.         *(AVFrame *)data = s->frame;

  1672.         avctx->sample_rate = s->sample_rate;

  1673.         //FIXME maybe move the other codec info stuff from above here too

  1674.     } else {

  1675.         av_log(avctx, AV_LOG_ERROR, "Error while decoding MPEG audio frame.\n");

  1676.         /* Only return an error if the bad frame makes up the whole packet or

  1677.          * the error is related to buffer management.

  1678.          * If there is more data in the packet, just consume the bad frame

  1679.          * instead of returning an error, which would discard the whole

  1680.          * packet. */

  1681.         *got_frame_ptr = 0;

  1682.         if (buf_size == avpkt->size || ret != AVERROR_INVALIDDATA)

  1683.             return ret;

  1684.     }

  1685.     s->frame_size = 0;

  1686.     return buf_size;

  1687. }

  1688. 

  1689. static void mp_flush(MPADecodeContext *ctx)

  1690. {

  1691.     memset(ctx->synth_buf, 0, sizeof(ctx->synth_buf));

  1692.     ctx->last_buf_size = 0;

  1693. }

  1694. 

  1695. static void flush(AVCodecContext *avctx)

  1696. {

  1697.     mp_flush(avctx->priv_data);

  1698. }

  1699. 

  1700. #if CONFIG_MP3ADU_DECODER || CONFIG_MP3ADUFLOAT_DECODER

  1701. static int decode_frame_adu(AVCodecContext *avctx, void *data,

  1702.                             int *got_frame_ptr, AVPacket *avpkt)

  1703. {

  1704.     const uint8_t *buf  = avpkt->data;

  1705.     int buf_size        = avpkt->size;

  1706.     MPADecodeContext *s = avctx->priv_data;

  1707.     uint32_t header;

  1708.     int len, ret;

  1709. 

  1710.     len = buf_size;

  1711. 

  1712.     // Discard too short frames

  1713.     if (buf_size < HEADER_SIZE) {

  1714.         av_log(avctx, AV_LOG_ERROR, "Packet is too small\n");

  1715.         return AVERROR_INVALIDDATA;

  1716.     }

  1717. 

  1718. 

  1719.     if (len > MPA_MAX_CODED_FRAME_SIZE)

  1720.         len = MPA_MAX_CODED_FRAME_SIZE;

  1721. 

  1722.     // Get header and restore sync word

  1723.     header = AV_RB32(buf) | 0xffe00000;

  1724. 

  1725.     if (ff_mpa_check_header(header) < 0) { // Bad header, discard frame

  1726.         av_log(avctx, AV_LOG_ERROR, "Invalid frame header\n");

  1727.         return AVERROR_INVALIDDATA;

  1728.     }

  1729. 

  1730.     avpriv_mpegaudio_decode_header((MPADecodeHeader *)s, header);

  1731.     /* update codec info */

  1732.     avctx->sample_rate = s->sample_rate;

  1733.     avctx->channels    = s->nb_channels;

  1734.     if (!avctx->bit_rate)

  1735.         avctx->bit_rate = s->bit_rate;

  1736. 

  1737.     s->frame_size = len;

  1738. 

  1739.     ret = mp_decode_frame(s, NULL, buf, buf_size);

  1740.     if (ret < 0) {

  1741.         av_log(avctx, AV_LOG_ERROR, "Error while decoding MPEG audio frame.\n");

  1742.         return ret;

  1743.     }

  1744. 

  1745.     *got_frame_ptr   = 1;

  1746.     *(AVFrame *)data = s->frame;

  1747. 

  1748.     return buf_size;

  1749. }

  1750. #endif /* CONFIG_MP3ADU_DECODER || CONFIG_MP3ADUFLOAT_DECODER */

  1751. 

  1752. #if CONFIG_MP3ON4_DECODER || CONFIG_MP3ON4FLOAT_DECODER

  1753. 

  1754. /**

  1755.  * Context for MP3On4 decoder

  1756.  */

  1757. typedef struct MP3On4DecodeContext {

  1758.     AVFrame *frame;

  1759.     int frames;                     ///< number of mp3 frames per block (number of mp3 decoder instances)

  1760.     int syncword;                   ///< syncword patch

  1761.     const uint8_t *coff;            ///< channel offsets in output buffer

  1762.     MPADecodeContext *mp3decctx[5]; ///< MPADecodeContext for every decoder instance

  1763.     OUT_INT *decoded_buf;           ///< output buffer for decoded samples

  1764. } MP3On4DecodeContext;

  1765. 

  1766. #include "mpeg4audio.h"

  1767. 

  1768. /* Next 3 arrays are indexed by channel config number (passed via codecdata) */

  1769. 

  1770. /* number of mp3 decoder instances */

  1771. static const uint8_t mp3Frames[8] = { 0, 1, 1, 2, 3, 3, 4, 5 };

  1772. 

  1773. /* offsets into output buffer, assume output order is FL FR C LFE BL BR SL SR */

  1774. static const uint8_t chan_offset[8][5] = {

  1775.     { 0             },

  1776.     { 0             },  // C

  1777.     { 0             },  // FLR

  1778.     { 2, 0          },  // C FLR

  1779.     { 2, 0, 3       },  // C FLR BS

  1780.     { 2, 0, 3       },  // C FLR BLRS

  1781.     { 2, 0, 4, 3    },  // C FLR BLRS LFE

  1782.     { 2, 0, 6, 4, 3 },  // C FLR BLRS BLR LFE

  1783. };

  1784. 

  1785. /* mp3on4 channel layouts */

  1786. static const int16_t chan_layout[8] = {

  1787.     0,

  1788.     AV_CH_LAYOUT_MONO,

  1789.     AV_CH_LAYOUT_STEREO,

  1790.     AV_CH_LAYOUT_SURROUND,

  1791.     AV_CH_LAYOUT_4POINT0,

  1792.     AV_CH_LAYOUT_5POINT0,

  1793.     AV_CH_LAYOUT_5POINT1,

  1794.     AV_CH_LAYOUT_7POINT1

  1795. };

  1796. 

  1797. static av_cold int decode_close_mp3on4(AVCodecContext * avctx)

  1798. {

  1799.     MP3On4DecodeContext *s = avctx->priv_data;

  1800.     int i;

  1801. 

  1802.     for (i = 0; i < s->frames; i++)

  1803.         av_free(s->mp3decctx[i]);

  1804. 

  1805.     av_freep(&s->decoded_buf);

  1806. 

  1807.     return 0;

  1808. }

  1809. 

  1810. 

  1811. static int decode_init_mp3on4(AVCodecContext * avctx)

  1812. {

  1813.     MP3On4DecodeContext *s = avctx->priv_data;

  1814.     MPEG4AudioConfig cfg;

  1815.     int i;

  1816. 

  1817.     if ((avctx->extradata_size < 2) || (avctx->extradata == NULL)) {

  1818.         av_log(avctx, AV_LOG_ERROR, "Codec extradata missing or too short.\n");

  1819.         return AVERROR_INVALIDDATA;

  1820.     }

  1821. 

  1822.     avpriv_mpeg4audio_get_config(&cfg, avctx->extradata,

  1823.                                  avctx->extradata_size * 8, 1);

  1824.     if (!cfg.chan_config || cfg.chan_config > 7) {

  1825.         av_log(avctx, AV_LOG_ERROR, "Invalid channel config number.\n");

  1826.         return AVERROR_INVALIDDATA;

  1827.     }

  1828.     s->frames             = mp3Frames[cfg.chan_config];

  1829.     s->coff               = chan_offset[cfg.chan_config];

  1830.     avctx->channels       = ff_mpeg4audio_channels[cfg.chan_config];

  1831.     avctx->channel_layout = chan_layout[cfg.chan_config];

  1832. 

  1833.     if (cfg.sample_rate < 16000)

  1834.         s->syncword = 0xffe00000;

  1835.     else

  1836.         s->syncword = 0xfff00000;

  1837. 

  1838.     /* Init the first mp3 decoder in standard way, so that all tables get builded

  1839.      * We replace avctx->priv_data with the context of the first decoder so that

  1840.      * decode_init() does not have to be changed.

  1841.      * Other decoders will be initialized here copying data from the first context

  1842.      */

  1843.     // Allocate zeroed memory for the first decoder context

  1844.     s->mp3decctx[0] = av_mallocz(sizeof(MPADecodeContext));

  1845.     if (!s->mp3decctx[0])

  1846.         goto alloc_fail;

  1847.     // Put decoder context in place to make init_decode() happy

  1848.     avctx->priv_data = s->mp3decctx[0];

  1849.     decode_init(avctx);

  1850.     s->frame = avctx->coded_frame;

  1851.     // Restore mp3on4 context pointer

  1852.     avctx->priv_data = s;

  1853.     s->mp3decctx[0]->adu_mode = 1; // Set adu mode

  1854. 

  1855.     /* Create a separate codec/context for each frame (first is already ok).

  1856.      * Each frame is 1 or 2 channels - up to 5 frames allowed

  1857.      */

  1858.     for (i = 1; i < s->frames; i++) {

  1859.         s->mp3decctx[i] = av_mallocz(sizeof(MPADecodeContext));

  1860.         if (!s->mp3decctx[i])

  1861.             goto alloc_fail;

  1862.         s->mp3decctx[i]->adu_mode = 1;

  1863.         s->mp3decctx[i]->avctx = avctx;

  1864.         s->mp3decctx[i]->mpadsp = s->mp3decctx[0]->mpadsp;

  1865.     }

  1866. 

  1867.     /* Allocate buffer for multi-channel output if needed */

  1868.     if (s->frames > 1) {

  1869.         s->decoded_buf = av_malloc(MPA_FRAME_SIZE * MPA_MAX_CHANNELS *

  1870.                                    sizeof(*s->decoded_buf));

  1871.         if (!s->decoded_buf)

  1872.             goto alloc_fail;

  1873.     }

  1874. 

  1875.     return 0;

  1876. alloc_fail:

  1877.     decode_close_mp3on4(avctx);

  1878.     return AVERROR(ENOMEM);

  1879. }

  1880. 

  1881. 

  1882. static void flush_mp3on4(AVCodecContext *avctx)

  1883. {

  1884.     int i;

  1885.     MP3On4DecodeContext *s = avctx->priv_data;

  1886. 

  1887.     for (i = 0; i < s->frames; i++)

  1888.         mp_flush(s->mp3decctx[i]);

  1889. }

  1890. 

  1891. 

  1892. static int decode_frame_mp3on4(AVCodecContext *avctx, void *data,

  1893.                                int *got_frame_ptr, AVPacket *avpkt)

  1894. {

  1895.     const uint8_t *buf     = avpkt->data;

  1896.     int buf_size           = avpkt->size;

  1897.     MP3On4DecodeContext *s = avctx->priv_data;

  1898.     MPADecodeContext *m;

  1899.     int fsize, len = buf_size, out_size = 0;

  1900.     uint32_t header;

  1901.     OUT_INT *out_samples;

  1902.     OUT_INT *outptr, *bp;

  1903.     int fr, j, n, ch, ret;

  1904. 

  1905.     /* get output buffer */

  1906.     s->frame->nb_samples = MPA_FRAME_SIZE;

  1907.     if ((ret = avctx->get_buffer(avctx, s->frame)) < 0) {

  1908.         av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");

  1909.         return ret;

  1910.     }

  1911.     out_samples = (OUT_INT *)s->frame->data[0];

  1912. 

  1913.     // Discard too short frames

  1914.     if (buf_size < HEADER_SIZE)

  1915.         return AVERROR_INVALIDDATA;

  1916. 

  1917.     // If only one decoder interleave is not needed

  1918.     outptr = s->frames == 1 ? out_samples : s->decoded_buf;

  1919. 

  1920.     avctx->bit_rate = 0;

  1921. 

  1922.     ch = 0;

  1923.     for (fr = 0; fr < s->frames; fr++) {

  1924.         fsize = AV_RB16(buf) >> 4;

  1925.         fsize = FFMIN3(fsize, len, MPA_MAX_CODED_FRAME_SIZE);

  1926.         m     = s->mp3decctx[fr];

  1927.         assert(m != NULL);

  1928. 

  1929.         if (fsize < HEADER_SIZE) {

  1930.             av_log(avctx, AV_LOG_ERROR, "Frame size smaller than header size\n");

  1931.             return AVERROR_INVALIDDATA;

  1932.         }

  1933.         header = (AV_RB32(buf) & 0x000fffff) | s->syncword; // patch header

  1934. 

  1935.         if (ff_mpa_check_header(header) < 0) // Bad header, discard block

  1936.             break;

  1937. 

  1938.         avpriv_mpegaudio_decode_header((MPADecodeHeader *)m, header);

  1939. 

  1940.         if (ch + m->nb_channels > avctx->channels) {

  1941.             av_log(avctx, AV_LOG_ERROR, "frame channel count exceeds codec "

  1942.                                         "channel count\n");

  1943.             return AVERROR_INVALIDDATA;

  1944.         }

  1945.         ch += m->nb_channels;

  1946. 

  1947.         if ((ret = mp_decode_frame(m, outptr, buf, fsize)) < 0)

  1948.             return ret;

  1949. 

  1950.         out_size += ret;

  1951.         buf      += fsize;

  1952.         len      -= fsize;

  1953. 

  1954.         if (s->frames > 1) {

  1955.             n = m->avctx->frame_size*m->nb_channels;

  1956.             /* interleave output data */

  1957.             bp = out_samples + s->coff[fr];

  1958.             if (m->nb_channels == 1) {

  1959.                 for (j = 0; j < n; j++) {

  1960.                     *bp = s->decoded_buf[j];

  1961.                     bp += avctx->channels;

  1962.                 }

  1963.             } else {

  1964.                 for (j = 0; j < n; j++) {

  1965.                     bp[0] = s->decoded_buf[j++];

  1966.                     bp[1] = s->decoded_buf[j];

  1967.                     bp   += avctx->channels;

  1968.                 }

  1969.             }

  1970.         }

  1971.         avctx->bit_rate += m->bit_rate;

  1972.     }

  1973. 

  1974.     /* update codec info */

  1975.     avctx->sample_rate = s->mp3decctx[0]->sample_rate;

  1976. 

  1977.     s->frame->nb_samples = out_size / (avctx->channels * sizeof(OUT_INT));

  1978.     *got_frame_ptr   = 1;

  1979.     *(AVFrame *)data = *s->frame;

  1980. 

  1981.     return buf_size;

  1982. }

  1983. #endif /* CONFIG_MP3ON4_DECODER || CONFIG_MP3ON4FLOAT_DECODER */

  1984. 

  1985. #if !CONFIG_FLOAT

  1986. #if CONFIG_MP1_DECODER

  1987. AVCodec ff_mp1_decoder = {

  1988.     .name           = "mp1",

  1989.     .type           = AVMEDIA_TYPE_AUDIO,

  1990.     .id             = AV_CODEC_ID_MP1,

  1991.     .priv_data_size = sizeof(MPADecodeContext),

  1992.     .init           = decode_init,

  1993.     .decode         = decode_frame,

  1994.     .capabilities   = CODEC_CAP_DR1,

  1995.     .flush          = flush,

  1996.     .long_name      = NULL_IF_CONFIG_SMALL("MP1 (MPEG audio layer 1)"),

  1997. };

  1998. #endif

  1999. #if CONFIG_MP2_DECODER

  2000. AVCodec ff_mp2_decoder = {

  2001.     .name           = "mp2",

  2002.     .type           = AVMEDIA_TYPE_AUDIO,

  2003.     .id             = AV_CODEC_ID_MP2,

  2004.     .priv_data_size = sizeof(MPADecodeContext),

  2005.     .init           = decode_init,

  2006.     .decode         = decode_frame,

  2007.     .capabilities   = CODEC_CAP_DR1,

  2008.     .flush          = flush,

  2009.     .long_name      = NULL_IF_CONFIG_SMALL("MP2 (MPEG audio layer 2)"),

  2010. };

  2011. #endif

  2012. #if CONFIG_MP3_DECODER

  2013. AVCodec ff_mp3_decoder = {

  2014.     .name           = "mp3",

  2015.     .type           = AVMEDIA_TYPE_AUDIO,

  2016.     .id             = AV_CODEC_ID_MP3,

  2017.     .priv_data_size = sizeof(MPADecodeContext),

  2018.     .init           = decode_init,

  2019.     .decode         = decode_frame,

  2020.     .capabilities   = CODEC_CAP_DR1,

  2021.     .flush          = flush,

  2022.     .long_name      = NULL_IF_CONFIG_SMALL("MP3 (MPEG audio layer 3)"),

  2023. };

  2024. #endif

  2025. #if CONFIG_MP3ADU_DECODER

  2026. AVCodec ff_mp3adu_decoder = {

  2027.     .name           = "mp3adu",

  2028.     .type           = AVMEDIA_TYPE_AUDIO,

  2029.     .id             = AV_CODEC_ID_MP3ADU,

  2030.     .priv_data_size = sizeof(MPADecodeContext),

  2031.     .init           = decode_init,

  2032.     .decode         = decode_frame_adu,

  2033.     .capabilities   = CODEC_CAP_DR1,

  2034.     .flush          = flush,

  2035.     .long_name      = NULL_IF_CONFIG_SMALL("ADU (Application Data Unit) MP3 (MPEG audio layer 3)"),

  2036. };

  2037. #endif

  2038. #if CONFIG_MP3ON4_DECODER

  2039. AVCodec ff_mp3on4_decoder = {

  2040.     .name           = "mp3on4",

  2041.     .type           = AVMEDIA_TYPE_AUDIO,

  2042.     .id             = AV_CODEC_ID_MP3ON4,

  2043.     .priv_data_size = sizeof(MP3On4DecodeContext),

  2044.     .init           = decode_init_mp3on4,

  2045.     .close          = decode_close_mp3on4,

  2046.     .decode         = decode_frame_mp3on4,

  2047.     .capabilities   = CODEC_CAP_DR1,

  2048.     .flush          = flush_mp3on4,

  2049.     .long_name      = NULL_IF_CONFIG_SMALL("MP3onMP4"),

  2050. };

  2051. #endif

  2052. #endif