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FFmpeg/libavcodec/mpegaudiodec_template.c

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  1. /*

  2.  * MPEG Audio decoder

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

  4.  *

  5.  * This file is part of FFmpeg.

  6.  *

  7.  * FFmpeg 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.  * FFmpeg 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 FFmpeg; 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/attributes.h"

  28. #include "libavutil/avassert.h"

  29. #include "libavutil/channel_layout.h"

  30. #include "libavutil/crc.h"

  31. #include "libavutil/float_dsp.h"

  32. #include "libavutil/libm.h"

  33. #include "libavutil/thread.h"

  34. #include "avcodec.h"

  35. #include "get_bits.h"

  36. #include "internal.h"

  37. #include "mathops.h"

  38. #include "mpegaudiodsp.h"

  39. 

  40. /*

  41.  * TODO:

  42.  *  - test lsf / mpeg25 extensively.

  43.  */

  44. 

  45. #include "mpegaudio.h"

  46. #include "mpegaudiodecheader.h"

  47. 

  48. #define BACKSTEP_SIZE 512

  49. #define EXTRABYTES 24

  50. #define LAST_BUF_SIZE 2 * BACKSTEP_SIZE + EXTRABYTES

  51. 

  52. /* layer 3 "granule" */

  53. typedef struct GranuleDef {

  54.     uint8_t scfsi;

  55.     int part2_3_length;

  56.     int big_values;

  57.     int global_gain;

  58.     int scalefac_compress;

  59.     uint8_t block_type;

  60.     uint8_t switch_point;

  61.     int table_select[3];

  62.     int subblock_gain[3];

  63.     uint8_t scalefac_scale;

  64.     uint8_t count1table_select;

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

  66.     int preflag;

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

  68.     uint8_t scale_factors[40];

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

  70. } GranuleDef;

  71. 

  72. typedef struct MPADecodeContext {

  73.     MPA_DECODE_HEADER

  74.     uint8_t last_buf[LAST_BUF_SIZE];

  75.     int last_buf_size;

  76.     int extrasize;

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

  78.     uint32_t free_format_next_header;

  79.     GetBitContext gb;

  80.     GetBitContext in_gb;

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

  82.     int synth_buf_offset[MPA_MAX_CHANNELS];

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

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

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

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

  87.     int dither_state;

  88.     int err_recognition;

  89.     AVCodecContext* avctx;

  90.     MPADSPContext mpadsp;

  91.     void (*butterflies_float)(float *av_restrict v1, float *av_restrict v2, int len);

  92.     AVFrame *frame;

  93.     uint32_t crc;

  94. } MPADecodeContext;

  95. 

  96. #define HEADER_SIZE 4

  97. 

  98. #include "mpegaudiodata.h"

  99. 

  100. #include "mpegaudio_tablegen.h"

  101. /* intensity stereo coef table */

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

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

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

  105. 

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

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

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

  109. 

  110. #define SCALE_GEN(v) \

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

  112. 

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

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

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

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

  117. };

  118. 

  119. /**

  120.  * Convert region offsets to region sizes and truncate

  121.  * size to big_values.

  122.  */

  123. static void region_offset2size(GranuleDef *g)

  124. {

  125.     int i, k, j = 0;

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

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

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

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

  130.         j = k;

  131.     }

  132. }

  133. 

  134. static void init_short_region(MPADecodeContext *s, GranuleDef *g)

  135. {

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

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

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

  139.         else

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

  141.     } else {

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

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

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

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

  146.         else

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

  148.     }

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

  150. }

  151. 

  152. static void init_long_region(MPADecodeContext *s, GranuleDef *g,

  153.                              int ra1, int ra2)

  154. {

  155.     int l;

  156.     g->region_size[0] = ff_band_index_long[s->sample_rate_index][ra1 + 1];

  157.     /* should not overflow */

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

  159.     g->region_size[1] = ff_band_index_long[s->sample_rate_index][      l];

  160. }

  161. 

  162. static void compute_band_indexes(MPADecodeContext *s, GranuleDef *g)

  163. {

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

  165.         if (g->switch_point) {

  166.             if(s->sample_rate_index == 8)

  167.                 avpriv_request_sample(s->avctx, "switch point in 8khz");

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

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

  170.                 exponents as long blocks */

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

  172.                 g->long_end = 8;

  173.             else

  174.                 g->long_end = 6;

  175. 

  176.             g->short_start = 3;

  177.         } else {

  178.             g->long_end    = 0;

  179.             g->short_start = 0;

  180.         }

  181.     } else {

  182.         g->short_start = 13;

  183.         g->long_end    = 22;

  184.     }

  185. }

  186. 

  187. /* layer 1 unscaling */

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

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

  190. {

  191.     int shift, mod;

  192.     int64_t val;

  193. 

  194.     shift   = ff_scale_factor_modshift[scale_factor];

  195.     mod     = shift & 3;

  196.     shift >>= 2;

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

  198.     shift  += n;

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

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

  201. }

  202. 

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

  204. {

  205.     int shift, mod, val;

  206. 

  207.     shift   = ff_scale_factor_modshift[scale_factor];

  208.     mod     = shift & 3;

  209.     shift >>= 2;

  210. 

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

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

  213.     if (shift > 0)

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

  215.     return val;

  216. }

  217. 

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

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

  220. {

  221.     unsigned int m;

  222.     int e;

  223. 

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

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

  226.     e -= exponent >> 2;

  227. #ifdef DEBUG

  228.     if(e < 1)

  229.         av_log(NULL, AV_LOG_WARNING, "l3_unscale: e is %d\n", e);

  230. #endif

  231.     if (e > (SUINT)31)

  232.         return 0;

  233.     m = (m + ((1U << e) >> 1)) >> e;

  234. 

  235.     return m;

  236. }

  237. 

  238. static av_cold void decode_init_static(void)

  239. {

  240.     int i, j;

  241. 

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

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

  244.         int n, norm;

  245.         n = i + 2;

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

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

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

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

  250.         ff_dlog(NULL, "%d: norm=%x s=%"PRIx32" %"PRIx32" %"PRIx32"\n", i,

  251.                 (unsigned)norm,

  252.                 scale_factor_mult[i][0],

  253.                 scale_factor_mult[i][1],

  254.                 scale_factor_mult[i][2]);

  255.     }

  256. 

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

  258. 

  259.     mpegaudio_tableinit();

  260. 

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

  262.         float f;

  263.         INTFLOAT v;

  264.         if (i != 6) {

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

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

  267.         } else {

  268.             v = FIXR(1.0);

  269.         }

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

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

  272.     }

  273.     /* invalid values */

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

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

  276. 

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

  278.         double f;

  279.         int e, k;

  280. 

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

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

  283.             f = exp2(e / 4.0);

  284.             k = i & 1;

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

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

  287.             ff_dlog(NULL, "is_table_lsf %d %d: %f %f\n",

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

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

  290.         }

  291.     }

  292. 

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

  294.         double ci, cs, ca;

  295.         ci = ff_ci_table[i];

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

  297.         ca = cs * ci;

  298. #if !USE_FLOATS

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

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

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

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

  303. #else

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

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

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

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

  308. #endif

  309.     }

  310.     RENAME(ff_mpa_synth_init)();

  311.     ff_mpegaudiodec_common_init_static();

  312. }

  313. 

  314. static av_cold int decode_init(AVCodecContext * avctx)

  315. {

  316.     static AVOnce init_static_once = AV_ONCE_INIT;

  317.     MPADecodeContext *s = avctx->priv_data;

  318. 

  319.     s->avctx = avctx;

  320. 

  321. #if USE_FLOATS

  322.     {

  323.         AVFloatDSPContext *fdsp;

  324.         fdsp = avpriv_float_dsp_alloc(avctx->flags & AV_CODEC_FLAG_BITEXACT);

  325.         if (!fdsp)

  326.             return AVERROR(ENOMEM);

  327.         s->butterflies_float = fdsp->butterflies_float;

  328.         av_free(fdsp);

  329.     }

  330. #endif

  331. 

  332.     ff_mpadsp_init(&s->mpadsp);

  333. 

  334.     if (avctx->request_sample_fmt == OUT_FMT &&

  335.         avctx->codec_id != AV_CODEC_ID_MP3ON4)

  336.         avctx->sample_fmt = OUT_FMT;

  337.     else

  338.         avctx->sample_fmt = OUT_FMT_P;

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

  340. 

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

  342.         s->adu_mode = 1;

  343. 

  344.     ff_thread_once(&init_static_once, decode_init_static);

  345. 

  346.     return 0;

  347. }

  348. 

  349. #define C3 FIXHR(0.86602540378443864676/2)

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

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

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

  353. 

  354. /* 12 points IMDCT. We compute it "by hand" by factorizing obvious

  355.    cases. */

  356. static void imdct12(INTFLOAT *out, SUINTFLOAT *in)

  357. {

  358.     SUINTFLOAT in0, in1, in2, in3, in4, in5, t1, t2;

  359. 

  360.     in0  = in[0*3];

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

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

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

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

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

  366.     in5 += in3;

  367.     in3 += in1;

  368. 

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

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

  371. 

  372.     t1   = in0 - in4;

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

  374. 

  375.     out[ 7] =

  376.     out[10] = t1 + t2;

  377.     out[ 1] =

  378.     out[ 4] = t1 - t2;

  379. 

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

  381.     in4     = in0 + in2;

  382.     in5    += 2*in1;

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

  384.     out[ 8] =

  385.     out[ 9] = in4 + in1;

  386.     out[ 2] =

  387.     out[ 3] = in4 - in1;

  388. 

  389.     in0    -= in2;

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

  391.     out[ 0] =

  392.     out[ 5] = in0 - in5;

  393.     out[ 6] =

  394.     out[11] = in0 + in5;

  395. }

  396. 

  397. static int handle_crc(MPADecodeContext *s, int sec_len)

  398. {

  399.     if (s->error_protection && (s->err_recognition & AV_EF_CRCCHECK)) {

  400.         const uint8_t *buf = s->gb.buffer - HEADER_SIZE;

  401.         int sec_byte_len  = sec_len >> 3;

  402.         int sec_rem_bits  = sec_len & 7;

  403.         const AVCRC *crc_tab = av_crc_get_table(AV_CRC_16_ANSI);

  404.         uint8_t tmp_buf[4];

  405.         uint32_t crc_val = av_crc(crc_tab, UINT16_MAX, &buf[2], 2);

  406.         crc_val = av_crc(crc_tab, crc_val, &buf[6], sec_byte_len);

  407. 

  408.         AV_WB32(tmp_buf,

  409.                 ((buf[6 + sec_byte_len] & (0xFF00 >> sec_rem_bits)) << 24) +

  410.                 ((s->crc << 16) >> sec_rem_bits));

  411. 

  412.         crc_val = av_crc(crc_tab, crc_val, tmp_buf, 3);

  413. 

  414.         if (crc_val) {

  415.             av_log(s->avctx, AV_LOG_ERROR, "CRC mismatch %X!\n", crc_val);

  416.             if (s->err_recognition & AV_EF_EXPLODE)

  417.                 return AVERROR_INVALIDDATA;

  418.         }

  419.     }

  420.     return 0;

  421. }

  422. 

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

  424. static int mp_decode_layer1(MPADecodeContext *s)

  425. {

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

  427.     uint8_t allocation[MPA_MAX_CHANNELS][SBLIMIT];

  428.     uint8_t scale_factors[MPA_MAX_CHANNELS][SBLIMIT];

  429.     int ret;

  430. 

  431.     ret = handle_crc(s, (s->nb_channels == 1) ? 8*16  : 8*32);

  432.     if (ret < 0)

  433.         return ret;

  434. 

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

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

  437.     else

  438.         bound = SBLIMIT;

  439. 

  440.     /* allocation bits */

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

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

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

  444.         }

  445.     }

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

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

  448. 

  449.     /* scale factors */

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

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

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

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

  454.         }

  455.     }

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

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

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

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

  460.         }

  461.     }

  462. 

  463.     /* compute samples */

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

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

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

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

  468.                 if (n) {

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

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

  471.                 } else {

  472.                     v = 0;

  473.                 }

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

  475.             }

  476.         }

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

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

  479.             if (n) {

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

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

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

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

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

  485.             } else {

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

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

  488.             }

  489.         }

  490.     }

  491.     return 12;

  492. }

  493. 

  494. static int mp_decode_layer2(MPADecodeContext *s)

  495. {

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

  497.     const unsigned char *alloc_table;

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

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

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

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

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

  503.     int ret;

  504. 

  505.     /* select decoding table */

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

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

  508.     sblimit     = ff_mpa_sblimit_table[table];

  509.     alloc_table = ff_mpa_alloc_tables[table];

  510. 

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

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

  513.     else

  514.         bound = sblimit;

  515. 

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

  517. 

  518.     /* sanity check */

  519.     if (bound > sblimit)

  520.         bound = sblimit;

  521. 

  522.     /* parse bit allocation */

  523.     j = 0;

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

  525.         bit_alloc_bits = alloc_table[j];

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

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

  528.         j += 1 << bit_alloc_bits;

  529.     }

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

  531.         bit_alloc_bits = alloc_table[j];

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

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

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

  535.         j += 1 << bit_alloc_bits;

  536.     }

  537. 

  538.     /* scale codes */

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

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

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

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

  543.         }

  544.     }

  545. 

  546.     ret = handle_crc(s, get_bits_count(&s->gb) - 16);

  547.     if (ret < 0)

  548.         return ret;

  549. 

  550.     /* scale factors */

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

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

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

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

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

  556.                 default:

  557.                 case 0:

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

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

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

  561.                     break;

  562.                 case 2:

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

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

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

  566.                     break;

  567.                 case 1:

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

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

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

  571.                     break;

  572.                 case 3:

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

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

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

  576.                     break;

  577.                 }

  578.             }

  579.         }

  580.     }

  581. 

  582.     /* samples */

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

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

  585.             j = 0;

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

  587.                 bit_alloc_bits = alloc_table[j];

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

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

  590.                     if (b) {

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

  592.                         qindex = alloc_table[j+b];

  593.                         bits = ff_mpa_quant_bits[qindex];

  594.                         if (bits < 0) {

  595.                             int v2;

  596.                             /* 3 values at the same time */

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

  598.                             v2 = ff_division_tabs[qindex][v];

  599.                             steps  = ff_mpa_quant_steps[qindex];

  600. 

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

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

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

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

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

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

  607.                         } else {

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

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

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

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

  612.                             }

  613.                         }

  614.                     } else {

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

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

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

  618.                     }

  619.                 }

  620.                 /* next subband in alloc table */

  621.                 j += 1 << bit_alloc_bits;

  622.             }

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

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

  625.                 bit_alloc_bits = alloc_table[j];

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

  627.                 if (b) {

  628.                     int mant, scale0, scale1;

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

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

  631.                     qindex = alloc_table[j + b];

  632.                     bits = ff_mpa_quant_bits[qindex];

  633.                     if (bits < 0) {

  634.                         /* 3 values at the same time */

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

  636.                         steps = ff_mpa_quant_steps[qindex];

  637.                         mant = v % steps;

  638.                         v = v / steps;

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

  640.                             l2_unscale_group(steps, mant, scale0);

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

  642.                             l2_unscale_group(steps, mant, scale1);

  643.                         mant = v % steps;

  644.                         v = v / steps;

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

  646.                             l2_unscale_group(steps, mant, scale0);

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

  648.                             l2_unscale_group(steps, mant, scale1);

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

  650.                             l2_unscale_group(steps, v, scale0);

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

  652.                             l2_unscale_group(steps, v, scale1);

  653.                     } else {

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

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

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

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

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

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

  660.                         }

  661.                     }

  662.                 } else {

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

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

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

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

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

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

  669.                 }

  670.                 /* next subband in alloc table */

  671.                 j += 1 << bit_alloc_bits;

  672.             }

  673.             /* fill remaining samples to zero */

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

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

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

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

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

  679.                 }

  680.             }

  681.         }

  682.     }

  683.     return 3 * 12;

  684. }

  685. 

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

  687.     if (n == 3) {                   \

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

  689.         dst   = sf - 3 * m;         \

  690.         sf    = m;                  \

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

  692.         dst  = sf & 3;              \

  693.         sf >>= 2;                   \

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

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

  696.         dst   = sf - 5 * m;         \

  697.         sf    = m;                  \

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

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

  700.         dst   = sf - 6 * m;         \

  701.         sf    = m;                  \

  702.     } else {                        \

  703.         dst = 0;                    \

  704.     }

  705. 

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

  707.                                            int n3)

  708. {

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

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

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

  712.     slen[0] = sf;

  713. }

  714. 

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

  716.                                          int16_t *exponents)

  717. {

  718.     const uint8_t *bstab, *pretab;

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

  720.     int16_t *exp_ptr;

  721. 

  722.     exp_ptr = exponents;

  723.     gain    = g->global_gain - 210;

  724.     shift   = g->scalefac_scale + 1;

  725. 

  726.     bstab  = ff_band_size_long[s->sample_rate_index];

  727.     pretab = ff_mpa_pretab[g->preflag];

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

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

  730.         len = bstab[i];

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

  732.             *exp_ptr++ = v0;

  733.     }

  734. 

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

  736.         bstab    = ff_band_size_short[s->sample_rate_index];

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

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

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

  740.         k        = g->long_end;

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

  742.             len = bstab[i];

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

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

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

  746.                     *exp_ptr++ = v0;

  747.             }

  748.         }

  749.     }

  750. }

  751. 

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

  753.                           int *end_pos2)

  754. {

  755.     if (s->in_gb.buffer && *pos >= s->gb.size_in_bits - s->extrasize * 8) {

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

  757.         s->in_gb.buffer = NULL;

  758.         s->extrasize    = 0;

  759.         av_assert2((get_bits_count(&s->gb) & 7) == 0);

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

  761.         *end_pos2 =

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

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

  764.     }

  765. }

  766. 

  767. /* Following is an optimized code for

  768.             INTFLOAT v = *src

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

  770.                 v = -v;

  771.             *dst = v;

  772. */

  773. #if USE_FLOATS

  774. #define READ_FLIP_SIGN(dst,src)                     \

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

  776.     AV_WN32A(dst, v);

  777. #else

  778. #define READ_FLIP_SIGN(dst,src)     \

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

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

  781. #endif

  782. 

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

  784.                           int16_t *exponents, int end_pos2)

  785. {

  786.     int s_index;

  787.     int i;

  788.     int last_pos, bits_left;

  789.     VLC *vlc;

  790.     int end_pos = FFMIN(end_pos2, s->gb.size_in_bits - s->extrasize * 8);

  791. 

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

  793.     s_index = 0;

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

  795.         int j, k, l, linbits;

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

  797.         if (j == 0)

  798.             continue;

  799.         /* select vlc table */

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

  801.         l       = ff_mpa_huff_data[k][0];

  802.         linbits = ff_mpa_huff_data[k][1];

  803.         vlc     = &ff_huff_vlc[l];

  804. 

  805.         if (!l) {

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

  807.             s_index += 2 * j;

  808.             continue;

  809.         }

  810. 

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

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

  813.             int exponent, x, y;

  814.             int v;

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

  816. 

  817.             if (pos >= end_pos){

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

  819.                 if (pos >= end_pos)

  820.                     break;

  821.             }

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

  823. 

  824.             if (!y) {

  825.                 g->sb_hybrid[s_index    ] =

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

  827.                 s_index += 2;

  828.                 continue;

  829.             }

  830. 

  831.             exponent= exponents[s_index];

  832. 

  833.             ff_dlog(s->avctx, "region=%d n=%d y=%d exp=%d\n",

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

  835.             if (y & 16) {

  836.                 x = y >> 5;

  837.                 y = y & 0x0f;

  838.                 if (x < 15) {

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

  840.                 } else {

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

  842.                     v  = l3_unscale(x, exponent);

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

  844.                         v = -v;

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

  846.                 }

  847.                 if (y < 15) {

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

  849.                 } else {

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

  851.                     v  = l3_unscale(y, exponent);

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

  853.                         v = -v;

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

  855.                 }

  856.             } else {

  857.                 x = y >> 5;

  858.                 y = y & 0x0f;

  859.                 x += y;

  860.                 if (x < 15) {

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

  862.                 } else {

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

  864.                     v  = l3_unscale(x, exponent);

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

  866.                         v = -v;

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

  868.                 }

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

  870.             }

  871.             s_index += 2;

  872.         }

  873.     }

  874. 

  875.     /* high frequencies */

  876.     vlc = &ff_huff_quad_vlc[g->count1table_select];

  877.     last_pos = 0;

  878.     while (s_index <= 572) {

  879.         int pos, code;

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

  881.         if (pos >= end_pos) {

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

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

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

  885.                 s_index -= 4;

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

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

  888.                 if(s->err_recognition & (AV_EF_BITSTREAM|AV_EF_COMPLIANT))

  889.                     s_index=0;

  890.                 break;

  891.             }

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

  893.             if (pos >= end_pos)

  894.                 break;

  895.         }

  896.         last_pos = pos;

  897. 

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

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

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

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

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

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

  904.         while (code) {

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

  906.             int v;

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

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

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

  910.         }

  911.         s_index += 4;

  912.     }

  913.     /* skip extension bits */

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

  915.     if (bits_left < 0 && (s->err_recognition & (AV_EF_BUFFER|AV_EF_COMPLIANT))) {

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

  917.         s_index=0;

  918.     } else if (bits_left > 0 && (s->err_recognition & (AV_EF_BUFFER|AV_EF_AGGRESSIVE))) {

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

  920.         s_index = 0;

  921.     }

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

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

  924. 

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

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

  927. 

  928.     return 0;

  929. }

  930. 

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

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

  933.    complicated */

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

  935. {

  936.     int i, j, len;

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

  938.     INTFLOAT tmp[576];

  939. 

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

  941.         return;

  942. 

  943.     if (g->switch_point) {

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

  945.             ptr = g->sb_hybrid + 36;

  946.         else

  947.             ptr = g->sb_hybrid + 72;

  948.     } else {

  949.         ptr = g->sb_hybrid;

  950.     }

  951. 

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

  953.         len  = ff_band_size_short[s->sample_rate_index][i];

  954.         ptr1 = ptr;

  955.         dst  = tmp;

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

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

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

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

  960.             ptr++;

  961.         }

  962.         ptr += 2 * len;

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

  964.     }

  965. }

  966. 

  967. #define ISQRT2 FIXR(0.70710678118654752440)

  968. 

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

  970. {

  971.     int i, j, k, l;

  972.     int sf_max, sf, len, non_zero_found;

  973.     INTFLOAT (*is_tab)[16], *tab0, *tab1, v1, v2;

  974.     SUINTFLOAT tmp0, tmp1;

  975.     int non_zero_found_short[3];

  976. 

  977.     /* intensity stereo */

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

  979.         if (!s->lsf) {

  980.             is_tab = is_table;

  981.             sf_max = 7;

  982.         } else {

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

  984.             sf_max = 16;

  985.         }

  986. 

  987.         tab0 = g0->sb_hybrid + 576;

  988.         tab1 = g1->sb_hybrid + 576;

  989. 

  990.         non_zero_found_short[0] = 0;

  991.         non_zero_found_short[1] = 0;

  992.         non_zero_found_short[2] = 0;

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

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

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

  996.             if (i != 11)

  997.                 k -= 3;

  998.             len = ff_band_size_short[s->sample_rate_index][i];

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

  1000.                 tab0 -= len;

  1001.                 tab1 -= len;

  1002.                 if (!non_zero_found_short[l]) {

  1003.                     /* test if non zero band. if so, stop doing i-stereo */

  1004.                     for (j = 0; j < len; j++) {

  1005.                         if (tab1[j] != 0) {

  1006.                             non_zero_found_short[l] = 1;

  1007.                             goto found1;

  1008.                         }

  1009.                     }

  1010.                     sf = g1->scale_factors[k + l];

  1011.                     if (sf >= sf_max)

  1012.                         goto found1;

  1013. 

  1014.                     v1 = is_tab[0][sf];

  1015.                     v2 = is_tab[1][sf];

  1016.                     for (j = 0; j < len; j++) {

  1017.                         tmp0    = tab0[j];

  1018.                         tab0[j] = MULLx(tmp0, v1, FRAC_BITS);

  1019.                         tab1[j] = MULLx(tmp0, v2, FRAC_BITS);

  1020.                     }

  1021.                 } else {

  1022. found1:

  1023.                     if (s->mode_ext & MODE_EXT_MS_STEREO) {

  1024.                         /* lower part of the spectrum : do ms stereo

  1025.                            if enabled */

  1026.                         for (j = 0; j < len; j++) {

  1027.                             tmp0    = tab0[j];

  1028.                             tmp1    = tab1[j];

  1029.                             tab0[j] = MULLx(tmp0 + tmp1, ISQRT2, FRAC_BITS);

  1030.                             tab1[j] = MULLx(tmp0 - tmp1, ISQRT2, FRAC_BITS);

  1031.                         }

  1032.                     }

  1033.                 }

  1034.             }

  1035.         }

  1036. 

  1037.         non_zero_found = non_zero_found_short[0] |

  1038.                          non_zero_found_short[1] |

  1039.                          non_zero_found_short[2];

  1040. 

  1041.         for (i = g1->long_end - 1;i >= 0;i--) {

  1042.             len   = ff_band_size_long[s->sample_rate_index][i];

  1043.             tab0 -= len;

  1044.             tab1 -= len;

  1045.             /* test if non zero band. if so, stop doing i-stereo */

  1046.             if (!non_zero_found) {

  1047.                 for (j = 0; j < len; j++) {

  1048.                     if (tab1[j] != 0) {

  1049.                         non_zero_found = 1;

  1050.                         goto found2;

  1051.                     }

  1052.                 }

  1053.                 /* for last band, use previous scale factor */

  1054.                 k  = (i == 21) ? 20 : i;

  1055.                 sf = g1->scale_factors[k];

  1056.                 if (sf >= sf_max)

  1057.                     goto found2;

  1058.                 v1 = is_tab[0][sf];

  1059.                 v2 = is_tab[1][sf];

  1060.                 for (j = 0; j < len; j++) {

  1061.                     tmp0    = tab0[j];

  1062.                     tab0[j] = MULLx(tmp0, v1, FRAC_BITS);

  1063.                     tab1[j] = MULLx(tmp0, v2, FRAC_BITS);

  1064.                 }

  1065.             } else {

  1066. found2:

  1067.                 if (s->mode_ext & MODE_EXT_MS_STEREO) {

  1068.                     /* lower part of the spectrum : do ms stereo

  1069.                        if enabled */

  1070.                     for (j = 0; j < len; j++) {

  1071.                         tmp0    = tab0[j];

  1072.                         tmp1    = tab1[j];

  1073.                         tab0[j] = MULLx(tmp0 + tmp1, ISQRT2, FRAC_BITS);

  1074.                         tab1[j] = MULLx(tmp0 - tmp1, ISQRT2, FRAC_BITS);

  1075.                     }

  1076.                 }

  1077.             }

  1078.         }

  1079.     } else if (s->mode_ext & MODE_EXT_MS_STEREO) {

  1080.         /* ms stereo ONLY */

  1081.         /* NOTE: the 1/sqrt(2) normalization factor is included in the

  1082.            global gain */

  1083. #if USE_FLOATS

  1084.        s->butterflies_float(g0->sb_hybrid, g1->sb_hybrid, 576);

  1085. #else

  1086.         tab0 = g0->sb_hybrid;

  1087.         tab1 = g1->sb_hybrid;

  1088.         for (i = 0; i < 576; i++) {

  1089.             tmp0    = tab0[i];

  1090.             tmp1    = tab1[i];

  1091.             tab0[i] = tmp0 + tmp1;

  1092.             tab1[i] = tmp0 - tmp1;

  1093.         }

  1094. #endif

  1095.     }

  1096. }

  1097. 

  1098. #if USE_FLOATS

  1099. #if HAVE_MIPSFPU

  1100. #   include "mips/compute_antialias_float.h"

  1101. #endif /* HAVE_MIPSFPU */

  1102. #else

  1103. #if HAVE_MIPSDSP

  1104. #   include "mips/compute_antialias_fixed.h"

  1105. #endif /* HAVE_MIPSDSP */

  1106. #endif /* USE_FLOATS */

  1107. 

  1108. #ifndef compute_antialias

  1109. #if USE_FLOATS

  1110. #define AA(j) do {                                                      \

  1111.         float tmp0 = ptr[-1-j];                                         \

  1112.         float tmp1 = ptr[   j];                                         \

  1113.         ptr[-1-j] = tmp0 * csa_table[j][0] - tmp1 * csa_table[j][1];    \

  1114.         ptr[   j] = tmp0 * csa_table[j][1] + tmp1 * csa_table[j][0];    \

  1115.     } while (0)

  1116. #else

  1117. #define AA(j) do {                                              \

  1118.         SUINT tmp0 = ptr[-1-j];                                   \

  1119.         SUINT tmp1 = ptr[   j];                                   \

  1120.         SUINT tmp2 = MULH(tmp0 + tmp1, csa_table[j][0]);          \

  1121.         ptr[-1-j] = 4 * (tmp2 - MULH(tmp1, csa_table[j][2]));   \

  1122.         ptr[   j] = 4 * (tmp2 + MULH(tmp0, csa_table[j][3]));   \

  1123.     } while (0)

  1124. #endif

  1125. 

  1126. static void compute_antialias(MPADecodeContext *s, GranuleDef *g)

  1127. {

  1128.     INTFLOAT *ptr;

  1129.     int n, i;

  1130. 

  1131.     /* we antialias only "long" bands */

  1132.     if (g->block_type == 2) {

  1133.         if (!g->switch_point)

  1134.             return;

  1135.         /* XXX: check this for 8000Hz case */

  1136.         n = 1;

  1137.     } else {

  1138.         n = SBLIMIT - 1;

  1139.     }

  1140. 

  1141.     ptr = g->sb_hybrid + 18;

  1142.     for (i = n; i > 0; i--) {

  1143.         AA(0);

  1144.         AA(1);

  1145.         AA(2);

  1146.         AA(3);

  1147.         AA(4);

  1148.         AA(5);

  1149.         AA(6);

  1150.         AA(7);

  1151. 

  1152.         ptr += 18;

  1153.     }

  1154. }

  1155. #endif /* compute_antialias */

  1156. 

  1157. static void compute_imdct(MPADecodeContext *s, GranuleDef *g,

  1158.                           INTFLOAT *sb_samples, INTFLOAT *mdct_buf)

  1159. {

  1160.     INTFLOAT *win, *out_ptr, *ptr, *buf, *ptr1;

  1161.     INTFLOAT out2[12];

  1162.     int i, j, mdct_long_end, sblimit;

  1163. 

  1164.     /* find last non zero block */

  1165.     ptr  = g->sb_hybrid + 576;

  1166.     ptr1 = g->sb_hybrid + 2 * 18;

  1167.     while (ptr >= ptr1) {

  1168.         int32_t *p;

  1169.         ptr -= 6;

  1170.         p    = (int32_t*)ptr;

  1171.         if (p[0] | p[1] | p[2] | p[3] | p[4] | p[5])

  1172.             break;

  1173.     }

  1174.     sblimit = ((ptr - g->sb_hybrid) / 18) + 1;

  1175. 

  1176.     if (g->block_type == 2) {

  1177.         /* XXX: check for 8000 Hz */

  1178.         if (g->switch_point)

  1179.             mdct_long_end = 2;

  1180.         else

  1181.             mdct_long_end = 0;

  1182.     } else {

  1183.         mdct_long_end = sblimit;

  1184.     }

  1185. 

  1186.     s->mpadsp.RENAME(imdct36_blocks)(sb_samples, mdct_buf, g->sb_hybrid,

  1187.                                      mdct_long_end, g->switch_point,

  1188.                                      g->block_type);

  1189. 

  1190.     buf = mdct_buf + 4*18*(mdct_long_end >> 2) + (mdct_long_end & 3);

  1191.     ptr = g->sb_hybrid + 18 * mdct_long_end;

  1192. 

  1193.     for (j = mdct_long_end; j < sblimit; j++) {

  1194.         /* select frequency inversion */

  1195.         win     = RENAME(ff_mdct_win)[2 + (4  & -(j & 1))];

  1196.         out_ptr = sb_samples + j;

  1197. 

  1198.         for (i = 0; i < 6; i++) {

  1199.             *out_ptr = buf[4*i];

  1200.             out_ptr += SBLIMIT;

  1201.         }

  1202.         imdct12(out2, ptr + 0);

  1203.         for (i = 0; i < 6; i++) {

  1204.             *out_ptr     = MULH3(out2[i    ], win[i    ], 1) + buf[4*(i + 6*1)];

  1205.             buf[4*(i + 6*2)] = MULH3(out2[i + 6], win[i + 6], 1);

  1206.             out_ptr += SBLIMIT;

  1207.         }

  1208.         imdct12(out2, ptr + 1);

  1209.         for (i = 0; i < 6; i++) {

  1210.             *out_ptr     = MULH3(out2[i    ], win[i    ], 1) + buf[4*(i + 6*2)];

  1211.             buf[4*(i + 6*0)] = MULH3(out2[i + 6], win[i + 6], 1);

  1212.             out_ptr += SBLIMIT;

  1213.         }

  1214.         imdct12(out2, ptr + 2);

  1215.         for (i = 0; i < 6; i++) {

  1216.             buf[4*(i + 6*0)] = MULH3(out2[i    ], win[i    ], 1) + buf[4*(i + 6*0)];

  1217.             buf[4*(i + 6*1)] = MULH3(out2[i + 6], win[i + 6], 1);

  1218.             buf[4*(i + 6*2)] = 0;

  1219.         }

  1220.         ptr += 18;

  1221.         buf += (j&3) != 3 ? 1 : (4*18-3);

  1222.     }

  1223.     /* zero bands */

  1224.     for (j = sblimit; j < SBLIMIT; j++) {

  1225.         /* overlap */

  1226.         out_ptr = sb_samples + j;

  1227.         for (i = 0; i < 18; i++) {

  1228.             *out_ptr = buf[4*i];

  1229.             buf[4*i]   = 0;

  1230.             out_ptr += SBLIMIT;

  1231.         }

  1232.         buf += (j&3) != 3 ? 1 : (4*18-3);

  1233.     }

  1234. }

  1235. 

  1236. /* main layer3 decoding function */

  1237. static int mp_decode_layer3(MPADecodeContext *s)

  1238. {

  1239.     int nb_granules, main_data_begin;

  1240.     int gr, ch, blocksplit_flag, i, j, k, n, bits_pos;

  1241.     GranuleDef *g;

  1242.     int16_t exponents[576]; //FIXME try INTFLOAT

  1243.     int ret;

  1244. 

  1245.     /* read side info */

  1246.     if (s->lsf) {

  1247.         ret = handle_crc(s, ((s->nb_channels == 1) ? 8*9  : 8*17));

  1248.         main_data_begin = get_bits(&s->gb, 8);

  1249.         skip_bits(&s->gb, s->nb_channels);

  1250.         nb_granules = 1;

  1251.     } else {

  1252.         ret = handle_crc(s, ((s->nb_channels == 1) ? 8*17 : 8*32));

  1253.         main_data_begin = get_bits(&s->gb, 9);

  1254.         if (s->nb_channels == 2)

  1255.             skip_bits(&s->gb, 3);

  1256.         else

  1257.             skip_bits(&s->gb, 5);

  1258.         nb_granules = 2;

  1259.         for (ch = 0; ch < s->nb_channels; ch++) {

  1260.             s->granules[ch][0].scfsi = 0;/* all scale factors are transmitted */

  1261.             s->granules[ch][1].scfsi = get_bits(&s->gb, 4);

  1262.         }

  1263.     }

  1264.     if (ret < 0)

  1265.         return ret;

  1266. 

  1267.     for (gr = 0; gr < nb_granules; gr++) {

  1268.         for (ch = 0; ch < s->nb_channels; ch++) {

  1269.             ff_dlog(s->avctx, "gr=%d ch=%d: side_info\n", gr, ch);

  1270.             g = &s->granules[ch][gr];

  1271.             g->part2_3_length = get_bits(&s->gb, 12);

  1272.             g->big_values     = get_bits(&s->gb,  9);

  1273.             if (g->big_values > 288) {

  1274.                 av_log(s->avctx, AV_LOG_ERROR, "big_values too big\n");

  1275.                 return AVERROR_INVALIDDATA;

  1276.             }

  1277. 

  1278.             g->global_gain = get_bits(&s->gb, 8);

  1279.             /* if MS stereo only is selected, we precompute the

  1280.                1/sqrt(2) renormalization factor */

  1281.             if ((s->mode_ext & (MODE_EXT_MS_STEREO | MODE_EXT_I_STEREO)) ==

  1282.                 MODE_EXT_MS_STEREO)

  1283.                 g->global_gain -= 2;

  1284.             if (s->lsf)

  1285.                 g->scalefac_compress = get_bits(&s->gb, 9);

  1286.             else

  1287.                 g->scalefac_compress = get_bits(&s->gb, 4);

  1288.             blocksplit_flag = get_bits1(&s->gb);

  1289.             if (blocksplit_flag) {

  1290.                 g->block_type = get_bits(&s->gb, 2);

  1291.                 if (g->block_type == 0) {

  1292.                     av_log(s->avctx, AV_LOG_ERROR, "invalid block type\n");

  1293.                     return AVERROR_INVALIDDATA;

  1294.                 }

  1295.                 g->switch_point = get_bits1(&s->gb);

  1296.                 for (i = 0; i < 2; i++)

  1297.                     g->table_select[i] = get_bits(&s->gb, 5);

  1298.                 for (i = 0; i < 3; i++)

  1299.                     g->subblock_gain[i] = get_bits(&s->gb, 3);

  1300.                 init_short_region(s, g);

  1301.             } else {

  1302.                 int region_address1, region_address2;

  1303.                 g->block_type = 0;

  1304.                 g->switch_point = 0;

  1305.                 for (i = 0; i < 3; i++)

  1306.                     g->table_select[i] = get_bits(&s->gb, 5);

  1307.                 /* compute huffman coded region sizes */

  1308.                 region_address1 = get_bits(&s->gb, 4);

  1309.                 region_address2 = get_bits(&s->gb, 3);

  1310.                 ff_dlog(s->avctx, "region1=%d region2=%d\n",

  1311.                         region_address1, region_address2);

  1312.                 init_long_region(s, g, region_address1, region_address2);

  1313.             }

  1314.             region_offset2size(g);

  1315.             compute_band_indexes(s, g);

  1316. 

  1317.             g->preflag = 0;

  1318.             if (!s->lsf)

  1319.                 g->preflag = get_bits1(&s->gb);

  1320.             g->scalefac_scale     = get_bits1(&s->gb);

  1321.             g->count1table_select = get_bits1(&s->gb);

  1322.             ff_dlog(s->avctx, "block_type=%d switch_point=%d\n",

  1323.                     g->block_type, g->switch_point);

  1324.         }

  1325.     }

  1326. 

  1327.     if (!s->adu_mode) {

  1328.         int skip;

  1329.         const uint8_t *ptr = s->gb.buffer + (get_bits_count(&s->gb) >> 3);

  1330.         s->extrasize = av_clip((get_bits_left(&s->gb) >> 3) - s->extrasize, 0,

  1331.                                FFMAX(0, LAST_BUF_SIZE - s->last_buf_size));

  1332.         av_assert1((get_bits_count(&s->gb) & 7) == 0);

  1333.         /* now we get bits from the main_data_begin offset */

  1334.         ff_dlog(s->avctx, "seekback:%d, lastbuf:%d\n",

  1335.                 main_data_begin, s->last_buf_size);

  1336. 

  1337.         memcpy(s->last_buf + s->last_buf_size, ptr, s->extrasize);

  1338.         s->in_gb = s->gb;

  1339.         init_get_bits(&s->gb, s->last_buf, (s->last_buf_size + s->extrasize) * 8);

  1340.         s->last_buf_size <<= 3;

  1341.         for (gr = 0; gr < nb_granules && (s->last_buf_size >> 3) < main_data_begin; gr++) {

  1342.             for (ch = 0; ch < s->nb_channels; ch++) {

  1343.                 g = &s->granules[ch][gr];

  1344.                 s->last_buf_size += g->part2_3_length;

  1345.                 memset(g->sb_hybrid, 0, sizeof(g->sb_hybrid));

  1346.                 compute_imdct(s, g, &s->sb_samples[ch][18 * gr][0], s->mdct_buf[ch]);

  1347.             }

  1348.         }

  1349.         skip = s->last_buf_size - 8 * main_data_begin;

  1350.         if (skip >= s->gb.size_in_bits - s->extrasize * 8 && s->in_gb.buffer) {

  1351.             skip_bits_long(&s->in_gb, skip - s->gb.size_in_bits + s->extrasize * 8);

  1352.             s->gb           = s->in_gb;

  1353.             s->in_gb.buffer = NULL;

  1354.             s->extrasize    = 0;

  1355.         } else {

  1356.             skip_bits_long(&s->gb, skip);

  1357.         }

  1358.     } else {

  1359.         gr = 0;

  1360.         s->extrasize = 0;

  1361.     }

  1362. 

  1363.     for (; gr < nb_granules; gr++) {

  1364.         for (ch = 0; ch < s->nb_channels; ch++) {

  1365.             g = &s->granules[ch][gr];

  1366.             bits_pos = get_bits_count(&s->gb);

  1367. 

  1368.             if (!s->lsf) {

  1369.                 uint8_t *sc;

  1370.                 int slen, slen1, slen2;

  1371. 

  1372.                 /* MPEG-1 scale factors */

  1373.                 slen1 = ff_slen_table[0][g->scalefac_compress];

  1374.                 slen2 = ff_slen_table[1][g->scalefac_compress];

  1375.                 ff_dlog(s->avctx, "slen1=%d slen2=%d\n", slen1, slen2);

  1376.                 if (g->block_type == 2) {

  1377.                     n = g->switch_point ? 17 : 18;

  1378.                     j = 0;

  1379.                     if (slen1) {

  1380.                         for (i = 0; i < n; i++)

  1381.                             g->scale_factors[j++] = get_bits(&s->gb, slen1);

  1382.                     } else {

  1383.                         for (i = 0; i < n; i++)

  1384.                             g->scale_factors[j++] = 0;

  1385.                     }

  1386.                     if (slen2) {

  1387.                         for (i = 0; i < 18; i++)

  1388.                             g->scale_factors[j++] = get_bits(&s->gb, slen2);

  1389.                         for (i = 0; i < 3; i++)

  1390.                             g->scale_factors[j++] = 0;

  1391.                     } else {

  1392.                         for (i = 0; i < 21; i++)

  1393.                             g->scale_factors[j++] = 0;

  1394.                     }

  1395.                 } else {

  1396.                     sc = s->granules[ch][0].scale_factors;

  1397.                     j = 0;

  1398.                     for (k = 0; k < 4; k++) {

  1399.                         n = k == 0 ? 6 : 5;

  1400.                         if ((g->scfsi & (0x8 >> k)) == 0) {

  1401.                             slen = (k < 2) ? slen1 : slen2;

  1402.                             if (slen) {

  1403.                                 for (i = 0; i < n; i++)

  1404.                                     g->scale_factors[j++] = get_bits(&s->gb, slen);

  1405.                             } else {

  1406.                                 for (i = 0; i < n; i++)

  1407.                                     g->scale_factors[j++] = 0;

  1408.                             }

  1409.                         } else {

  1410.                             /* simply copy from last granule */

  1411.                             for (i = 0; i < n; i++) {

  1412.                                 g->scale_factors[j] = sc[j];

  1413.                                 j++;

  1414.                             }

  1415.                         }

  1416.                     }

  1417.                     g->scale_factors[j++] = 0;

  1418.                 }

  1419.             } else {

  1420.                 int tindex, tindex2, slen[4], sl, sf;

  1421. 

  1422.                 /* LSF scale factors */

  1423.                 if (g->block_type == 2)

  1424.                     tindex = g->switch_point ? 2 : 1;

  1425.                 else

  1426.                     tindex = 0;

  1427. 

  1428.                 sf = g->scalefac_compress;

  1429.                 if ((s->mode_ext & MODE_EXT_I_STEREO) && ch == 1) {

  1430.                     /* intensity stereo case */

  1431.                     sf >>= 1;

  1432.                     if (sf < 180) {

  1433.                         lsf_sf_expand(slen, sf, 6, 6, 0);

  1434.                         tindex2 = 3;

  1435.                     } else if (sf < 244) {

  1436.                         lsf_sf_expand(slen, sf - 180, 4, 4, 0);

  1437.                         tindex2 = 4;

  1438.                     } else {

  1439.                         lsf_sf_expand(slen, sf - 244, 3, 0, 0);

  1440.                         tindex2 = 5;

  1441.                     }

  1442.                 } else {

  1443.                     /* normal case */

  1444.                     if (sf < 400) {

  1445.                         lsf_sf_expand(slen, sf, 5, 4, 4);

  1446.                         tindex2 = 0;

  1447.                     } else if (sf < 500) {

  1448.                         lsf_sf_expand(slen, sf - 400, 5, 4, 0);

  1449.                         tindex2 = 1;

  1450.                     } else {

  1451.                         lsf_sf_expand(slen, sf - 500, 3, 0, 0);

  1452.                         tindex2 = 2;

  1453.                         g->preflag = 1;

  1454.                     }

  1455.                 }

  1456. 

  1457.                 j = 0;

  1458.                 for (k = 0; k < 4; k++) {

  1459.                     n  = ff_lsf_nsf_table[tindex2][tindex][k];

  1460.                     sl = slen[k];

  1461.                     if (sl) {

  1462.                         for (i = 0; i < n; i++)

  1463.                             g->scale_factors[j++] = get_bits(&s->gb, sl);

  1464.                     } else {

  1465.                         for (i = 0; i < n; i++)

  1466.                             g->scale_factors[j++] = 0;

  1467.                     }

  1468.                 }

  1469.                 /* XXX: should compute exact size */

  1470.                 for (; j < 40; j++)

  1471.                     g->scale_factors[j] = 0;

  1472.             }

  1473. 

  1474.             exponents_from_scale_factors(s, g, exponents);

  1475. 

  1476.             /* read Huffman coded residue */

  1477.             huffman_decode(s, g, exponents, bits_pos + g->part2_3_length);

  1478.         } /* ch */

  1479. 

  1480.         if (s->mode == MPA_JSTEREO)

  1481.             compute_stereo(s, &s->granules[0][gr], &s->granules[1][gr]);

  1482. 

  1483.         for (ch = 0; ch < s->nb_channels; ch++) {

  1484.             g = &s->granules[ch][gr];

  1485. 

  1486.             reorder_block(s, g);

  1487.             compute_antialias(s, g);

  1488.             compute_imdct(s, g, &s->sb_samples[ch][18 * gr][0], s->mdct_buf[ch]);

  1489.         }

  1490.     } /* gr */

  1491.     if (get_bits_count(&s->gb) < 0)

  1492.         skip_bits_long(&s->gb, -get_bits_count(&s->gb));

  1493.     return nb_granules * 18;

  1494. }

  1495. 

  1496. static int mp_decode_frame(MPADecodeContext *s, OUT_INT **samples,

  1497.                            const uint8_t *buf, int buf_size)

  1498. {

  1499.     int i, nb_frames, ch, ret;

  1500.     OUT_INT *samples_ptr;

  1501. 

  1502.     init_get_bits(&s->gb, buf + HEADER_SIZE, (buf_size - HEADER_SIZE) * 8);

  1503.     if (s->error_protection)

  1504.         s->crc = get_bits(&s->gb, 16);

  1505. 

  1506.     switch(s->layer) {

  1507.     case 1:

  1508.         s->avctx->frame_size = 384;

  1509.         nb_frames = mp_decode_layer1(s);

  1510.         break;

  1511.     case 2:

  1512.         s->avctx->frame_size = 1152;

  1513.         nb_frames = mp_decode_layer2(s);

  1514.         break;

  1515.     case 3:

  1516.         s->avctx->frame_size = s->lsf ? 576 : 1152;

  1517.     default:

  1518.         nb_frames = mp_decode_layer3(s);

  1519. 

  1520.         s->last_buf_size=0;

  1521.         if (s->in_gb.buffer) {

  1522.             align_get_bits(&s->gb);

  1523.             i = (get_bits_left(&s->gb) >> 3) - s->extrasize;

  1524.             if (i >= 0 && i <= BACKSTEP_SIZE) {

  1525.                 memmove(s->last_buf, s->gb.buffer + (get_bits_count(&s->gb) >> 3), i);

  1526.                 s->last_buf_size=i;

  1527.             } else

  1528.                 av_log(s->avctx, AV_LOG_ERROR, "invalid old backstep %d\n", i);

  1529.             s->gb           = s->in_gb;

  1530.             s->in_gb.buffer = NULL;

  1531.             s->extrasize    = 0;

  1532.         }

  1533. 

  1534.         align_get_bits(&s->gb);

  1535.         av_assert1((get_bits_count(&s->gb) & 7) == 0);

  1536.         i = (get_bits_left(&s->gb) >> 3) - s->extrasize;

  1537.         if (i < 0 || i > BACKSTEP_SIZE || nb_frames < 0) {

  1538.             if (i < 0)

  1539.                 av_log(s->avctx, AV_LOG_ERROR, "invalid new backstep %d\n", i);

  1540.             i = FFMIN(BACKSTEP_SIZE, buf_size - HEADER_SIZE);

  1541.         }

  1542.         av_assert1(i <= buf_size - HEADER_SIZE && i >= 0);

  1543.         memcpy(s->last_buf + s->last_buf_size, s->gb.buffer + buf_size - HEADER_SIZE - i, i);

  1544.         s->last_buf_size += i;

  1545.     }

  1546. 

  1547.     if(nb_frames < 0)

  1548.         return nb_frames;

  1549. 

  1550.     /* get output buffer */

  1551.     if (!samples) {

  1552.         av_assert0(s->frame);

  1553.         s->frame->nb_samples = s->avctx->frame_size;

  1554.         if ((ret = ff_get_buffer(s->avctx, s->frame, 0)) < 0)

  1555.             return ret;

  1556.         samples = (OUT_INT **)s->frame->extended_data;

  1557.     }

  1558. 

  1559.     /* apply the synthesis filter */

  1560.     for (ch = 0; ch < s->nb_channels; ch++) {

  1561.         int sample_stride;

  1562.         if (s->avctx->sample_fmt == OUT_FMT_P) {

  1563.             samples_ptr   = samples[ch];

  1564.             sample_stride = 1;

  1565.         } else {

  1566.             samples_ptr   = samples[0] + ch;

  1567.             sample_stride = s->nb_channels;

  1568.         }

  1569.         for (i = 0; i < nb_frames; i++) {

  1570.             RENAME(ff_mpa_synth_filter)(&s->mpadsp, s->synth_buf[ch],

  1571.                                         &(s->synth_buf_offset[ch]),

  1572.                                         RENAME(ff_mpa_synth_window),

  1573.                                         &s->dither_state, samples_ptr,

  1574.                                         sample_stride, s->sb_samples[ch][i]);

  1575.             samples_ptr += 32 * sample_stride;

  1576.         }

  1577.     }

  1578. 

  1579.     return nb_frames * 32 * sizeof(OUT_INT) * s->nb_channels;

  1580. }

  1581. 

  1582. static int decode_frame(AVCodecContext * avctx, void *data, int *got_frame_ptr,

  1583.                         AVPacket *avpkt)

  1584. {

  1585.     const uint8_t *buf  = avpkt->data;

  1586.     int buf_size        = avpkt->size;

  1587.     MPADecodeContext *s = avctx->priv_data;

  1588.     uint32_t header;

  1589.     int ret;

  1590. 

  1591.     int skipped = 0;

  1592.     while(buf_size && !*buf){

  1593.         buf++;

  1594.         buf_size--;

  1595.         skipped++;

  1596.     }

  1597. 

  1598.     if (buf_size < HEADER_SIZE)

  1599.         return AVERROR_INVALIDDATA;

  1600. 

  1601.     header = AV_RB32(buf);

  1602.     if (header >> 8 == AV_RB32("TAG") >> 8) {

  1603.         av_log(avctx, AV_LOG_DEBUG, "discarding ID3 tag\n");

  1604.         return buf_size + skipped;

  1605.     }

  1606.     ret = avpriv_mpegaudio_decode_header((MPADecodeHeader *)s, header);

  1607.     if (ret < 0) {

  1608.         av_log(avctx, AV_LOG_ERROR, "Header missing\n");

  1609.         return AVERROR_INVALIDDATA;

  1610.     } else if (ret == 1) {

  1611.         /* free format: prepare to compute frame size */

  1612.         s->frame_size = -1;

  1613.         return AVERROR_INVALIDDATA;

  1614.     }

  1615.     /* update codec info */

  1616.     avctx->channels       = s->nb_channels;

  1617.     avctx->channel_layout = s->nb_channels == 1 ? AV_CH_LAYOUT_MONO : AV_CH_LAYOUT_STEREO;

  1618.     if (!avctx->bit_rate)

  1619.         avctx->bit_rate = s->bit_rate;

  1620. 

  1621.     if (s->frame_size <= 0) {

  1622.         av_log(avctx, AV_LOG_ERROR, "incomplete frame\n");

  1623.         return AVERROR_INVALIDDATA;

  1624.     } else if (s->frame_size < buf_size) {

  1625.         av_log(avctx, AV_LOG_DEBUG, "incorrect frame size - multiple frames in buffer?\n");

  1626.         buf_size= s->frame_size;

  1627.     }

  1628. 

  1629.     s->frame = data;

  1630. 

  1631.     ret = mp_decode_frame(s, NULL, buf, buf_size);

  1632.     if (ret >= 0) {

  1633.         s->frame->nb_samples = avctx->frame_size;

  1634.         *got_frame_ptr       = 1;

  1635.         avctx->sample_rate   = s->sample_rate;

  1636.         //FIXME maybe move the other codec info stuff from above here too

  1637.     } else {

  1638.         av_log(avctx, AV_LOG_ERROR, "Error while decoding MPEG audio frame.\n");

  1639.         /* Only return an error if the bad frame makes up the whole packet or

  1640.          * the error is related to buffer management.

  1641.          * If there is more data in the packet, just consume the bad frame

  1642.          * instead of returning an error, which would discard the whole

  1643.          * packet. */

  1644.         *got_frame_ptr = 0;

  1645.         if (buf_size == avpkt->size || ret != AVERROR_INVALIDDATA)

  1646.             return ret;

  1647.     }

  1648.     s->frame_size = 0;

  1649.     return buf_size + skipped;

  1650. }

  1651. 

  1652. static void mp_flush(MPADecodeContext *ctx)

  1653. {

  1654.     memset(ctx->synth_buf, 0, sizeof(ctx->synth_buf));

  1655.     memset(ctx->mdct_buf, 0, sizeof(ctx->mdct_buf));

  1656.     ctx->last_buf_size = 0;

  1657.     ctx->dither_state = 0;

  1658. }

  1659. 

  1660. static void flush(AVCodecContext *avctx)

  1661. {

  1662.     mp_flush(avctx->priv_data);

  1663. }

  1664. 

  1665. #if CONFIG_MP3ADU_DECODER || CONFIG_MP3ADUFLOAT_DECODER

  1666. static int decode_frame_adu(AVCodecContext *avctx, void *data,

  1667.                             int *got_frame_ptr, AVPacket *avpkt)

  1668. {

  1669.     const uint8_t *buf  = avpkt->data;

  1670.     int buf_size        = avpkt->size;

  1671.     MPADecodeContext *s = avctx->priv_data;

  1672.     uint32_t header;

  1673.     int len, ret;

  1674.     int av_unused out_size;

  1675. 

  1676.     len = buf_size;

  1677. 

  1678.     // Discard too short frames

  1679.     if (buf_size < HEADER_SIZE) {

  1680.         av_log(avctx, AV_LOG_ERROR, "Packet is too small\n");

  1681.         return AVERROR_INVALIDDATA;

  1682.     }

  1683. 

  1684. 

  1685.     if (len > MPA_MAX_CODED_FRAME_SIZE)

  1686.         len = MPA_MAX_CODED_FRAME_SIZE;

  1687. 

  1688.     // Get header and restore sync word

  1689.     header = AV_RB32(buf) | 0xffe00000;

  1690. 

  1691.     ret = avpriv_mpegaudio_decode_header((MPADecodeHeader *)s, header);

  1692.     if (ret < 0) {

  1693.         av_log(avctx, AV_LOG_ERROR, "Invalid frame header\n");

  1694.         return ret;

  1695.     }

  1696.     /* update codec info */

  1697.     avctx->sample_rate = s->sample_rate;

  1698.     avctx->channels    = s->nb_channels;

  1699.     avctx->channel_layout = s->nb_channels == 1 ? AV_CH_LAYOUT_MONO : AV_CH_LAYOUT_STEREO;

  1700.     if (!avctx->bit_rate)

  1701.         avctx->bit_rate = s->bit_rate;

  1702. 

  1703.     s->frame_size = len;

  1704. 

  1705.     s->frame = data;

  1706. 

  1707.     ret = mp_decode_frame(s, NULL, buf, buf_size);

  1708.     if (ret < 0) {

  1709.         av_log(avctx, AV_LOG_ERROR, "Error while decoding MPEG audio frame.\n");

  1710.         return ret;

  1711.     }

  1712. 

  1713.     *got_frame_ptr = 1;

  1714. 

  1715.     return buf_size;

  1716. }

  1717. #endif /* CONFIG_MP3ADU_DECODER || CONFIG_MP3ADUFLOAT_DECODER */

  1718. 

  1719. #if CONFIG_MP3ON4_DECODER || CONFIG_MP3ON4FLOAT_DECODER

  1720. 

  1721. /**

  1722.  * Context for MP3On4 decoder

  1723.  */

  1724. typedef struct MP3On4DecodeContext {

  1725.     int frames;                     ///< number of mp3 frames per block (number of mp3 decoder instances)

  1726.     int syncword;                   ///< syncword patch

  1727.     const uint8_t *coff;            ///< channel offsets in output buffer

  1728.     MPADecodeContext *mp3decctx[5]; ///< MPADecodeContext for every decoder instance

  1729. } MP3On4DecodeContext;

  1730. 

  1731. #include "mpeg4audio.h"

  1732. 

  1733. /* Next 3 arrays are indexed by channel config number (passed via codecdata) */

  1734. 

  1735. /* number of mp3 decoder instances */

  1736. static const uint8_t mp3Frames[8] = { 0, 1, 1, 2, 3, 3, 4, 5 };

  1737. 

  1738. /* offsets into output buffer, assume output order is FL FR C LFE BL BR SL SR */

  1739. static const uint8_t chan_offset[8][5] = {

  1740.     { 0             },

  1741.     { 0             },  // C

  1742.     { 0             },  // FLR

  1743.     { 2, 0          },  // C FLR

  1744.     { 2, 0, 3       },  // C FLR BS

  1745.     { 2, 0, 3       },  // C FLR BLRS

  1746.     { 2, 0, 4, 3    },  // C FLR BLRS LFE

  1747.     { 2, 0, 6, 4, 3 },  // C FLR BLRS BLR LFE

  1748. };

  1749. 

  1750. /* mp3on4 channel layouts */

  1751. static const int16_t chan_layout[8] = {

  1752.     0,

  1753.     AV_CH_LAYOUT_MONO,

  1754.     AV_CH_LAYOUT_STEREO,

  1755.     AV_CH_LAYOUT_SURROUND,

  1756.     AV_CH_LAYOUT_4POINT0,

  1757.     AV_CH_LAYOUT_5POINT0,

  1758.     AV_CH_LAYOUT_5POINT1,

  1759.     AV_CH_LAYOUT_7POINT1

  1760. };

  1761. 

  1762. static av_cold int decode_close_mp3on4(AVCodecContext * avctx)

  1763. {

  1764.     MP3On4DecodeContext *s = avctx->priv_data;

  1765.     int i;

  1766. 

  1767.     for (i = 0; i < s->frames; i++)

  1768.         av_freep(&s->mp3decctx[i]);

  1769. 

  1770.     return 0;

  1771. }

  1772. 

  1773. 

  1774. static av_cold int decode_init_mp3on4(AVCodecContext * avctx)

  1775. {

  1776.     MP3On4DecodeContext *s = avctx->priv_data;

  1777.     MPEG4AudioConfig cfg;

  1778.     int i, ret;

  1779. 

  1780.     if ((avctx->extradata_size < 2) || !avctx->extradata) {

  1781.         av_log(avctx, AV_LOG_ERROR, "Codec extradata missing or too short.\n");

  1782.         return AVERROR_INVALIDDATA;

  1783.     }

  1784. 

  1785.     avpriv_mpeg4audio_get_config2(&cfg, avctx->extradata,

  1786.                                   avctx->extradata_size, 1, avctx);

  1787.     if (!cfg.chan_config || cfg.chan_config > 7) {

  1788.         av_log(avctx, AV_LOG_ERROR, "Invalid channel config number.\n");

  1789.         return AVERROR_INVALIDDATA;

  1790.     }

  1791.     s->frames             = mp3Frames[cfg.chan_config];

  1792.     s->coff               = chan_offset[cfg.chan_config];

  1793.     avctx->channels       = ff_mpeg4audio_channels[cfg.chan_config];

  1794.     avctx->channel_layout = chan_layout[cfg.chan_config];

  1795. 

  1796.     if (cfg.sample_rate < 16000)

  1797.         s->syncword = 0xffe00000;

  1798.     else

  1799.         s->syncword = 0xfff00000;

  1800. 

  1801.     /* Init the first mp3 decoder in standard way, so that all tables get builded

  1802.      * We replace avctx->priv_data with the context of the first decoder so that

  1803.      * decode_init() does not have to be changed.

  1804.      * Other decoders will be initialized here copying data from the first context

  1805.      */

  1806.     // Allocate zeroed memory for the first decoder context

  1807.     s->mp3decctx[0] = av_mallocz(sizeof(MPADecodeContext));

  1808.     if (!s->mp3decctx[0])

  1809.         return AVERROR(ENOMEM);

  1810.     // Put decoder context in place to make init_decode() happy

  1811.     avctx->priv_data = s->mp3decctx[0];

  1812.     ret = decode_init(avctx);

  1813.     // Restore mp3on4 context pointer

  1814.     avctx->priv_data = s;

  1815.     if (ret < 0)

  1816.         return ret;

  1817.     s->mp3decctx[0]->adu_mode = 1; // Set adu mode

  1818. 

  1819.     /* Create a separate codec/context for each frame (first is already ok).

  1820.      * Each frame is 1 or 2 channels - up to 5 frames allowed

  1821.      */

  1822.     for (i = 1; i < s->frames; i++) {

  1823.         s->mp3decctx[i] = av_mallocz(sizeof(MPADecodeContext));

  1824.         if (!s->mp3decctx[i])

  1825.             return AVERROR(ENOMEM);

  1826.         s->mp3decctx[i]->adu_mode = 1;

  1827.         s->mp3decctx[i]->avctx = avctx;

  1828.         s->mp3decctx[i]->mpadsp = s->mp3decctx[0]->mpadsp;

  1829.         s->mp3decctx[i]->butterflies_float = s->mp3decctx[0]->butterflies_float;

  1830.     }

  1831. 

  1832.     return 0;

  1833. }

  1834. 

  1835. 

  1836. static void flush_mp3on4(AVCodecContext *avctx)

  1837. {

  1838.     int i;

  1839.     MP3On4DecodeContext *s = avctx->priv_data;

  1840. 

  1841.     for (i = 0; i < s->frames; i++)

  1842.         mp_flush(s->mp3decctx[i]);

  1843. }

  1844. 

  1845. 

  1846. static int decode_frame_mp3on4(AVCodecContext *avctx, void *data,

  1847.                                int *got_frame_ptr, AVPacket *avpkt)

  1848. {

  1849.     AVFrame *frame         = data;

  1850.     const uint8_t *buf     = avpkt->data;

  1851.     int buf_size           = avpkt->size;

  1852.     MP3On4DecodeContext *s = avctx->priv_data;

  1853.     MPADecodeContext *m;

  1854.     int fsize, len = buf_size, out_size = 0;

  1855.     uint32_t header;

  1856.     OUT_INT **out_samples;

  1857.     OUT_INT *outptr[2];

  1858.     int fr, ch, ret;

  1859. 

  1860.     /* get output buffer */

  1861.     frame->nb_samples = MPA_FRAME_SIZE;

  1862.     if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)

  1863.         return ret;

  1864.     out_samples = (OUT_INT **)frame->extended_data;

  1865. 

  1866.     // Discard too short frames

  1867.     if (buf_size < HEADER_SIZE)

  1868.         return AVERROR_INVALIDDATA;

  1869. 

  1870.     avctx->bit_rate = 0;

  1871. 

  1872.     ch = 0;

  1873.     for (fr = 0; fr < s->frames; fr++) {

  1874.         fsize = AV_RB16(buf) >> 4;

  1875.         fsize = FFMIN3(fsize, len, MPA_MAX_CODED_FRAME_SIZE);

  1876.         m     = s->mp3decctx[fr];

  1877.         av_assert1(m);

  1878. 

  1879.         if (fsize < HEADER_SIZE) {

  1880.             av_log(avctx, AV_LOG_ERROR, "Frame size smaller than header size\n");

  1881.             return AVERROR_INVALIDDATA;

  1882.         }

  1883.         header = (AV_RB32(buf) & 0x000fffff) | s->syncword; // patch header

  1884. 

  1885.         ret = avpriv_mpegaudio_decode_header((MPADecodeHeader *)m, header);

  1886.         if (ret < 0) {

  1887.             av_log(avctx, AV_LOG_ERROR, "Bad header, discard block\n");

  1888.             return AVERROR_INVALIDDATA;

  1889.         }

  1890. 

  1891.         if (ch + m->nb_channels > avctx->channels ||

  1892.             s->coff[fr] + m->nb_channels > avctx->channels) {

  1893.             av_log(avctx, AV_LOG_ERROR, "frame channel count exceeds codec "

  1894.                                         "channel count\n");

  1895.             return AVERROR_INVALIDDATA;

  1896.         }

  1897.         ch += m->nb_channels;

  1898. 

  1899.         outptr[0] = out_samples[s->coff[fr]];

  1900.         if (m->nb_channels > 1)

  1901.             outptr[1] = out_samples[s->coff[fr] + 1];

  1902. 

  1903.         if ((ret = mp_decode_frame(m, outptr, buf, fsize)) < 0) {

  1904.             av_log(avctx, AV_LOG_ERROR, "failed to decode channel %d\n", ch);

  1905.             memset(outptr[0], 0, MPA_FRAME_SIZE*sizeof(OUT_INT));

  1906.             if (m->nb_channels > 1)

  1907.                 memset(outptr[1], 0, MPA_FRAME_SIZE*sizeof(OUT_INT));

  1908.             ret = m->nb_channels * MPA_FRAME_SIZE*sizeof(OUT_INT);

  1909.         }

  1910. 

  1911.         out_size += ret;

  1912.         buf      += fsize;

  1913.         len      -= fsize;

  1914. 

  1915.         avctx->bit_rate += m->bit_rate;

  1916.     }

  1917.     if (ch != avctx->channels) {

  1918.         av_log(avctx, AV_LOG_ERROR, "failed to decode all channels\n");

  1919.         return AVERROR_INVALIDDATA;

  1920.     }

  1921. 

  1922.     /* update codec info */

  1923.     avctx->sample_rate = s->mp3decctx[0]->sample_rate;

  1924. 

  1925.     frame->nb_samples = out_size / (avctx->channels * sizeof(OUT_INT));

  1926.     *got_frame_ptr    = 1;

  1927. 

  1928.     return buf_size;

  1929. }

  1930. #endif /* CONFIG_MP3ON4_DECODER || CONFIG_MP3ON4FLOAT_DECODER */