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FFmpeg/libavcodec/aacsbr.c

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  1. /*

  2.  * AAC Spectral Band Replication decoding functions

  3.  * Copyright (c) 2008-2009 Robert Swain ( rob opendot cl )

  4.  * Copyright (c) 2009-2010 Alex Converse <alex.converse@gmail.com>

  5.  *

  6.  * This file is part of Libav.

  7.  *

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

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

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

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

  12.  *

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

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

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

  16.  * Lesser General Public License for more details.

  17.  *

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

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

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

  21.  */

  22. 

  23. /**

  24.  * @file

  25.  * AAC Spectral Band Replication decoding functions

  26.  * @author Robert Swain ( rob opendot cl )

  27.  */

  28. 

  29. #include "aac.h"

  30. #include "sbr.h"

  31. #include "aacsbr.h"

  32. #include "aacsbrdata.h"

  33. #include "fft.h"

  34. #include "aacps.h"

  35. #include "libavutil/libm.h"

  36. 

  37. #include <stdint.h>

  38. #include <float.h>

  39. 

  40. #define ENVELOPE_ADJUSTMENT_OFFSET 2

  41. #define NOISE_FLOOR_OFFSET 6.0f

  42. 

  43. /**

  44.  * SBR VLC tables

  45.  */

  46. enum {

  47.     T_HUFFMAN_ENV_1_5DB,

  48.     F_HUFFMAN_ENV_1_5DB,

  49.     T_HUFFMAN_ENV_BAL_1_5DB,

  50.     F_HUFFMAN_ENV_BAL_1_5DB,

  51.     T_HUFFMAN_ENV_3_0DB,

  52.     F_HUFFMAN_ENV_3_0DB,

  53.     T_HUFFMAN_ENV_BAL_3_0DB,

  54.     F_HUFFMAN_ENV_BAL_3_0DB,

  55.     T_HUFFMAN_NOISE_3_0DB,

  56.     T_HUFFMAN_NOISE_BAL_3_0DB,

  57. };

  58. 

  59. /**

  60.  * bs_frame_class - frame class of current SBR frame (14496-3 sp04 p98)

  61.  */

  62. enum {

  63.     FIXFIX,

  64.     FIXVAR,

  65.     VARFIX,

  66.     VARVAR,

  67. };

  68. 

  69. enum {

  70.     EXTENSION_ID_PS = 2,

  71. };

  72. 

  73. static VLC vlc_sbr[10];

  74. static const int8_t vlc_sbr_lav[10] =

  75.     { 60, 60, 24, 24, 31, 31, 12, 12, 31, 12 };

  76. static const DECLARE_ALIGNED(16, float, zero64)[64];

  77. 

  78. #define SBR_INIT_VLC_STATIC(num, size) \

  79.     INIT_VLC_STATIC(&vlc_sbr[num], 9, sbr_tmp[num].table_size / sbr_tmp[num].elem_size,     \

  80.                     sbr_tmp[num].sbr_bits ,                      1,                      1, \

  81.                     sbr_tmp[num].sbr_codes, sbr_tmp[num].elem_size, sbr_tmp[num].elem_size, \

  82.                     size)

  83. 

  84. #define SBR_VLC_ROW(name) \

  85.     { name ## _codes, name ## _bits, sizeof(name ## _codes), sizeof(name ## _codes[0]) }

  86. 

  87. av_cold void ff_aac_sbr_init(void)

  88. {

  89.     int n;

  90.     static const struct {

  91.         const void *sbr_codes, *sbr_bits;

  92.         const unsigned int table_size, elem_size;

  93.     } sbr_tmp[] = {

  94.         SBR_VLC_ROW(t_huffman_env_1_5dB),

  95.         SBR_VLC_ROW(f_huffman_env_1_5dB),

  96.         SBR_VLC_ROW(t_huffman_env_bal_1_5dB),

  97.         SBR_VLC_ROW(f_huffman_env_bal_1_5dB),

  98.         SBR_VLC_ROW(t_huffman_env_3_0dB),

  99.         SBR_VLC_ROW(f_huffman_env_3_0dB),

  100.         SBR_VLC_ROW(t_huffman_env_bal_3_0dB),

  101.         SBR_VLC_ROW(f_huffman_env_bal_3_0dB),

  102.         SBR_VLC_ROW(t_huffman_noise_3_0dB),

  103.         SBR_VLC_ROW(t_huffman_noise_bal_3_0dB),

  104.     };

  105. 

  106.     // SBR VLC table initialization

  107.     SBR_INIT_VLC_STATIC(0, 1098);

  108.     SBR_INIT_VLC_STATIC(1, 1092);

  109.     SBR_INIT_VLC_STATIC(2, 768);

  110.     SBR_INIT_VLC_STATIC(3, 1026);

  111.     SBR_INIT_VLC_STATIC(4, 1058);

  112.     SBR_INIT_VLC_STATIC(5, 1052);

  113.     SBR_INIT_VLC_STATIC(6, 544);

  114.     SBR_INIT_VLC_STATIC(7, 544);

  115.     SBR_INIT_VLC_STATIC(8, 592);

  116.     SBR_INIT_VLC_STATIC(9, 512);

  117. 

  118.     for (n = 1; n < 320; n++)

  119.         sbr_qmf_window_us[320 + n] = sbr_qmf_window_us[320 - n];

  120.     sbr_qmf_window_us[384] = -sbr_qmf_window_us[384];

  121.     sbr_qmf_window_us[512] = -sbr_qmf_window_us[512];

  122. 

  123.     for (n = 0; n < 320; n++)

  124.         sbr_qmf_window_ds[n] = sbr_qmf_window_us[2*n];

  125. 

  126.     ff_ps_init();

  127. }

  128. 

  129. av_cold void ff_aac_sbr_ctx_init(SpectralBandReplication *sbr)

  130. {

  131.     sbr->kx[0] = sbr->kx[1] = 32; //Typo in spec, kx' inits to 32

  132.     sbr->data[0].e_a[1] = sbr->data[1].e_a[1] = -1;

  133.     sbr->data[0].synthesis_filterbank_samples_offset = SBR_SYNTHESIS_BUF_SIZE - (1280 - 128);

  134.     sbr->data[1].synthesis_filterbank_samples_offset = SBR_SYNTHESIS_BUF_SIZE - (1280 - 128);

  135.     ff_mdct_init(&sbr->mdct, 7, 1, 1.0/64);

  136.     ff_mdct_init(&sbr->mdct_ana, 7, 1, -2.0);

  137.     ff_ps_ctx_init(&sbr->ps);

  138. }

  139. 

  140. av_cold void ff_aac_sbr_ctx_close(SpectralBandReplication *sbr)

  141. {

  142.     ff_mdct_end(&sbr->mdct);

  143.     ff_mdct_end(&sbr->mdct_ana);

  144. }

  145. 

  146. static int qsort_comparison_function_int16(const void *a, const void *b)

  147. {

  148.     return *(const int16_t *)a - *(const int16_t *)b;

  149. }

  150. 

  151. static inline int in_table_int16(const int16_t *table, int last_el, int16_t needle)

  152. {

  153.     int i;

  154.     for (i = 0; i <= last_el; i++)

  155.         if (table[i] == needle)

  156.             return 1;

  157.     return 0;

  158. }

  159. 

  160. /// Limiter Frequency Band Table (14496-3 sp04 p198)

  161. static void sbr_make_f_tablelim(SpectralBandReplication *sbr)

  162. {

  163.     int k;

  164.     if (sbr->bs_limiter_bands > 0) {

  165.         static const float bands_warped[3] = { 1.32715174233856803909f,   //2^(0.49/1.2)

  166.                                                1.18509277094158210129f,   //2^(0.49/2)

  167.                                                1.11987160404675912501f }; //2^(0.49/3)

  168.         const float lim_bands_per_octave_warped = bands_warped[sbr->bs_limiter_bands - 1];

  169.         int16_t patch_borders[7];

  170.         uint16_t *in = sbr->f_tablelim + 1, *out = sbr->f_tablelim;

  171. 

  172.         patch_borders[0] = sbr->kx[1];

  173.         for (k = 1; k <= sbr->num_patches; k++)

  174.             patch_borders[k] = patch_borders[k-1] + sbr->patch_num_subbands[k-1];

  175. 

  176.         memcpy(sbr->f_tablelim, sbr->f_tablelow,

  177.                (sbr->n[0] + 1) * sizeof(sbr->f_tablelow[0]));

  178.         if (sbr->num_patches > 1)

  179.             memcpy(sbr->f_tablelim + sbr->n[0] + 1, patch_borders + 1,

  180.                    (sbr->num_patches - 1) * sizeof(patch_borders[0]));

  181. 

  182.         qsort(sbr->f_tablelim, sbr->num_patches + sbr->n[0],

  183.               sizeof(sbr->f_tablelim[0]),

  184.               qsort_comparison_function_int16);

  185. 

  186.         sbr->n_lim = sbr->n[0] + sbr->num_patches - 1;

  187.         while (out < sbr->f_tablelim + sbr->n_lim) {

  188.             if (*in >= *out * lim_bands_per_octave_warped) {

  189.                 *++out = *in++;

  190.             } else if (*in == *out ||

  191.                 !in_table_int16(patch_borders, sbr->num_patches, *in)) {

  192.                 in++;

  193.                 sbr->n_lim--;

  194.             } else if (!in_table_int16(patch_borders, sbr->num_patches, *out)) {

  195.                 *out = *in++;

  196.                 sbr->n_lim--;

  197.             } else {

  198.                 *++out = *in++;

  199.             }

  200.         }

  201.     } else {

  202.         sbr->f_tablelim[0] = sbr->f_tablelow[0];

  203.         sbr->f_tablelim[1] = sbr->f_tablelow[sbr->n[0]];

  204.         sbr->n_lim = 1;

  205.     }

  206. }

  207. 

  208. static unsigned int read_sbr_header(SpectralBandReplication *sbr, GetBitContext *gb)

  209. {

  210.     unsigned int cnt = get_bits_count(gb);

  211.     uint8_t bs_header_extra_1;

  212.     uint8_t bs_header_extra_2;

  213.     int old_bs_limiter_bands = sbr->bs_limiter_bands;

  214.     SpectrumParameters old_spectrum_params;

  215. 

  216.     sbr->start = 1;

  217. 

  218.     // Save last spectrum parameters variables to compare to new ones

  219.     memcpy(&old_spectrum_params, &sbr->spectrum_params, sizeof(SpectrumParameters));

  220. 

  221.     sbr->bs_amp_res_header              = get_bits1(gb);

  222.     sbr->spectrum_params.bs_start_freq  = get_bits(gb, 4);

  223.     sbr->spectrum_params.bs_stop_freq   = get_bits(gb, 4);

  224.     sbr->spectrum_params.bs_xover_band  = get_bits(gb, 3);

  225.                                           skip_bits(gb, 2); // bs_reserved

  226. 

  227.     bs_header_extra_1 = get_bits1(gb);

  228.     bs_header_extra_2 = get_bits1(gb);

  229. 

  230.     if (bs_header_extra_1) {

  231.         sbr->spectrum_params.bs_freq_scale  = get_bits(gb, 2);

  232.         sbr->spectrum_params.bs_alter_scale = get_bits1(gb);

  233.         sbr->spectrum_params.bs_noise_bands = get_bits(gb, 2);

  234.     } else {

  235.         sbr->spectrum_params.bs_freq_scale  = 2;

  236.         sbr->spectrum_params.bs_alter_scale = 1;

  237.         sbr->spectrum_params.bs_noise_bands = 2;

  238.     }

  239. 

  240.     // Check if spectrum parameters changed

  241.     if (memcmp(&old_spectrum_params, &sbr->spectrum_params, sizeof(SpectrumParameters)))

  242.         sbr->reset = 1;

  243. 

  244.     if (bs_header_extra_2) {

  245.         sbr->bs_limiter_bands  = get_bits(gb, 2);

  246.         sbr->bs_limiter_gains  = get_bits(gb, 2);

  247.         sbr->bs_interpol_freq  = get_bits1(gb);

  248.         sbr->bs_smoothing_mode = get_bits1(gb);

  249.     } else {

  250.         sbr->bs_limiter_bands  = 2;

  251.         sbr->bs_limiter_gains  = 2;

  252.         sbr->bs_interpol_freq  = 1;

  253.         sbr->bs_smoothing_mode = 1;

  254.     }

  255. 

  256.     if (sbr->bs_limiter_bands != old_bs_limiter_bands && !sbr->reset)

  257.         sbr_make_f_tablelim(sbr);

  258. 

  259.     return get_bits_count(gb) - cnt;

  260. }

  261. 

  262. static int array_min_int16(const int16_t *array, int nel)

  263. {

  264.     int i, min = array[0];

  265.     for (i = 1; i < nel; i++)

  266.         min = FFMIN(array[i], min);

  267.     return min;

  268. }

  269. 

  270. static void make_bands(int16_t* bands, int start, int stop, int num_bands)

  271. {

  272.     int k, previous, present;

  273.     float base, prod;

  274. 

  275.     base = powf((float)stop / start, 1.0f / num_bands);

  276.     prod = start;

  277.     previous = start;

  278. 

  279.     for (k = 0; k < num_bands-1; k++) {

  280.         prod *= base;

  281.         present  = lrintf(prod);

  282.         bands[k] = present - previous;

  283.         previous = present;

  284.     }

  285.     bands[num_bands-1] = stop - previous;

  286. }

  287. 

  288. static int check_n_master(AVCodecContext *avctx, int n_master, int bs_xover_band)

  289. {

  290.     // Requirements (14496-3 sp04 p205)

  291.     if (n_master <= 0) {

  292.         av_log(avctx, AV_LOG_ERROR, "Invalid n_master: %d\n", n_master);

  293.         return -1;

  294.     }

  295.     if (bs_xover_band >= n_master) {

  296.         av_log(avctx, AV_LOG_ERROR,

  297.                "Invalid bitstream, crossover band index beyond array bounds: %d\n",

  298.                bs_xover_band);

  299.         return -1;

  300.     }

  301.     return 0;

  302. }

  303. 

  304. /// Master Frequency Band Table (14496-3 sp04 p194)

  305. static int sbr_make_f_master(AACContext *ac, SpectralBandReplication *sbr,

  306.                              SpectrumParameters *spectrum)

  307. {

  308.     unsigned int temp, max_qmf_subbands;

  309.     unsigned int start_min, stop_min;

  310.     int k;

  311.     const int8_t *sbr_offset_ptr;

  312.     int16_t stop_dk[13];

  313. 

  314.     if (sbr->sample_rate < 32000) {

  315.         temp = 3000;

  316.     } else if (sbr->sample_rate < 64000) {

  317.         temp = 4000;

  318.     } else

  319.         temp = 5000;

  320. 

  321.     start_min = ((temp << 7) + (sbr->sample_rate >> 1)) / sbr->sample_rate;

  322.     stop_min  = ((temp << 8) + (sbr->sample_rate >> 1)) / sbr->sample_rate;

  323. 

  324.     switch (sbr->sample_rate) {

  325.     case 16000:

  326.         sbr_offset_ptr = sbr_offset[0];

  327.         break;

  328.     case 22050:

  329.         sbr_offset_ptr = sbr_offset[1];

  330.         break;

  331.     case 24000:

  332.         sbr_offset_ptr = sbr_offset[2];

  333.         break;

  334.     case 32000:

  335.         sbr_offset_ptr = sbr_offset[3];

  336.         break;

  337.     case 44100: case 48000: case 64000:

  338.         sbr_offset_ptr = sbr_offset[4];

  339.         break;

  340.     case 88200: case 96000: case 128000: case 176400: case 192000:

  341.         sbr_offset_ptr = sbr_offset[5];

  342.         break;

  343.     default:

  344.         av_log(ac->avctx, AV_LOG_ERROR,

  345.                "Unsupported sample rate for SBR: %d\n", sbr->sample_rate);

  346.         return -1;

  347.     }

  348. 

  349.     sbr->k[0] = start_min + sbr_offset_ptr[spectrum->bs_start_freq];

  350. 

  351.     if (spectrum->bs_stop_freq < 14) {

  352.         sbr->k[2] = stop_min;

  353.         make_bands(stop_dk, stop_min, 64, 13);

  354.         qsort(stop_dk, 13, sizeof(stop_dk[0]), qsort_comparison_function_int16);

  355.         for (k = 0; k < spectrum->bs_stop_freq; k++)

  356.             sbr->k[2] += stop_dk[k];

  357.     } else if (spectrum->bs_stop_freq == 14) {

  358.         sbr->k[2] = 2*sbr->k[0];

  359.     } else if (spectrum->bs_stop_freq == 15) {

  360.         sbr->k[2] = 3*sbr->k[0];

  361.     } else {

  362.         av_log(ac->avctx, AV_LOG_ERROR,

  363.                "Invalid bs_stop_freq: %d\n", spectrum->bs_stop_freq);

  364.         return -1;

  365.     }

  366.     sbr->k[2] = FFMIN(64, sbr->k[2]);

  367. 

  368.     // Requirements (14496-3 sp04 p205)

  369.     if (sbr->sample_rate <= 32000) {

  370.         max_qmf_subbands = 48;

  371.     } else if (sbr->sample_rate == 44100) {

  372.         max_qmf_subbands = 35;

  373.     } else if (sbr->sample_rate >= 48000)

  374.         max_qmf_subbands = 32;

  375. 

  376.     if (sbr->k[2] - sbr->k[0] > max_qmf_subbands) {

  377.         av_log(ac->avctx, AV_LOG_ERROR,

  378.                "Invalid bitstream, too many QMF subbands: %d\n", sbr->k[2] - sbr->k[0]);

  379.         return -1;

  380.     }

  381. 

  382.     if (!spectrum->bs_freq_scale) {

  383.         int dk, k2diff;

  384. 

  385.         dk = spectrum->bs_alter_scale + 1;

  386.         sbr->n_master = ((sbr->k[2] - sbr->k[0] + (dk&2)) >> dk) << 1;

  387.         if (check_n_master(ac->avctx, sbr->n_master, sbr->spectrum_params.bs_xover_band))

  388.             return -1;

  389. 

  390.         for (k = 1; k <= sbr->n_master; k++)

  391.             sbr->f_master[k] = dk;

  392. 

  393.         k2diff = sbr->k[2] - sbr->k[0] - sbr->n_master * dk;

  394.         if (k2diff < 0) {

  395.             sbr->f_master[1]--;

  396.             sbr->f_master[2]-= (k2diff < -1);

  397.         } else if (k2diff) {

  398.             sbr->f_master[sbr->n_master]++;

  399.         }

  400. 

  401.         sbr->f_master[0] = sbr->k[0];

  402.         for (k = 1; k <= sbr->n_master; k++)

  403.             sbr->f_master[k] += sbr->f_master[k - 1];

  404. 

  405.     } else {

  406.         int half_bands = 7 - spectrum->bs_freq_scale;      // bs_freq_scale  = {1,2,3}

  407.         int two_regions, num_bands_0;

  408.         int vdk0_max, vdk1_min;

  409.         int16_t vk0[49];

  410. 

  411.         if (49 * sbr->k[2] > 110 * sbr->k[0]) {

  412.             two_regions = 1;

  413.             sbr->k[1] = 2 * sbr->k[0];

  414.         } else {

  415.             two_regions = 0;

  416.             sbr->k[1] = sbr->k[2];

  417.         }

  418. 

  419.         num_bands_0 = lrintf(half_bands * log2f(sbr->k[1] / (float)sbr->k[0])) * 2;

  420. 

  421.         if (num_bands_0 <= 0) { // Requirements (14496-3 sp04 p205)

  422.             av_log(ac->avctx, AV_LOG_ERROR, "Invalid num_bands_0: %d\n", num_bands_0);

  423.             return -1;

  424.         }

  425. 

  426.         vk0[0] = 0;

  427. 

  428.         make_bands(vk0+1, sbr->k[0], sbr->k[1], num_bands_0);

  429. 

  430.         qsort(vk0 + 1, num_bands_0, sizeof(vk0[1]), qsort_comparison_function_int16);

  431.         vdk0_max = vk0[num_bands_0];

  432. 

  433.         vk0[0] = sbr->k[0];

  434.         for (k = 1; k <= num_bands_0; k++) {

  435.             if (vk0[k] <= 0) { // Requirements (14496-3 sp04 p205)

  436.                 av_log(ac->avctx, AV_LOG_ERROR, "Invalid vDk0[%d]: %d\n", k, vk0[k]);

  437.                 return -1;

  438.             }

  439.             vk0[k] += vk0[k-1];

  440.         }

  441. 

  442.         if (two_regions) {

  443.             int16_t vk1[49];

  444.             float invwarp = spectrum->bs_alter_scale ? 0.76923076923076923077f

  445.                                                      : 1.0f; // bs_alter_scale = {0,1}

  446.             int num_bands_1 = lrintf(half_bands * invwarp *

  447.                                      log2f(sbr->k[2] / (float)sbr->k[1])) * 2;

  448. 

  449.             make_bands(vk1+1, sbr->k[1], sbr->k[2], num_bands_1);

  450. 

  451.             vdk1_min = array_min_int16(vk1 + 1, num_bands_1);

  452. 

  453.             if (vdk1_min < vdk0_max) {

  454.                 int change;

  455.                 qsort(vk1 + 1, num_bands_1, sizeof(vk1[1]), qsort_comparison_function_int16);

  456.                 change = FFMIN(vdk0_max - vk1[1], (vk1[num_bands_1] - vk1[1]) >> 1);

  457.                 vk1[1]           += change;

  458.                 vk1[num_bands_1] -= change;

  459.             }

  460. 

  461.             qsort(vk1 + 1, num_bands_1, sizeof(vk1[1]), qsort_comparison_function_int16);

  462. 

  463.             vk1[0] = sbr->k[1];

  464.             for (k = 1; k <= num_bands_1; k++) {

  465.                 if (vk1[k] <= 0) { // Requirements (14496-3 sp04 p205)

  466.                     av_log(ac->avctx, AV_LOG_ERROR, "Invalid vDk1[%d]: %d\n", k, vk1[k]);

  467.                     return -1;

  468.                 }

  469.                 vk1[k] += vk1[k-1];

  470.             }

  471. 

  472.             sbr->n_master = num_bands_0 + num_bands_1;

  473.             if (check_n_master(ac->avctx, sbr->n_master, sbr->spectrum_params.bs_xover_band))

  474.                 return -1;

  475.             memcpy(&sbr->f_master[0],               vk0,

  476.                    (num_bands_0 + 1) * sizeof(sbr->f_master[0]));

  477.             memcpy(&sbr->f_master[num_bands_0 + 1], vk1 + 1,

  478.                     num_bands_1      * sizeof(sbr->f_master[0]));

  479. 

  480.         } else {

  481.             sbr->n_master = num_bands_0;

  482.             if (check_n_master(ac->avctx, sbr->n_master, sbr->spectrum_params.bs_xover_band))

  483.                 return -1;

  484.             memcpy(sbr->f_master, vk0, (num_bands_0 + 1) * sizeof(sbr->f_master[0]));

  485.         }

  486.     }

  487. 

  488.     return 0;

  489. }

  490. 

  491. /// High Frequency Generation - Patch Construction (14496-3 sp04 p216 fig. 4.46)

  492. static int sbr_hf_calc_npatches(AACContext *ac, SpectralBandReplication *sbr)

  493. {

  494.     int i, k, sb = 0;

  495.     int msb = sbr->k[0];

  496.     int usb = sbr->kx[1];

  497.     int goal_sb = ((1000 << 11) + (sbr->sample_rate >> 1)) / sbr->sample_rate;

  498. 

  499.     sbr->num_patches = 0;

  500. 

  501.     if (goal_sb < sbr->kx[1] + sbr->m[1]) {

  502.         for (k = 0; sbr->f_master[k] < goal_sb; k++) ;

  503.     } else

  504.         k = sbr->n_master;

  505. 

  506.     do {

  507.         int odd = 0;

  508.         for (i = k; i == k || sb > (sbr->k[0] - 1 + msb - odd); i--) {

  509.             sb = sbr->f_master[i];

  510.             odd = (sb + sbr->k[0]) & 1;

  511.         }

  512. 

  513.         // Requirements (14496-3 sp04 p205) sets the maximum number of patches to 5.

  514.         // After this check the final number of patches can still be six which is

  515.         // illegal however the Coding Technologies decoder check stream has a final

  516.         // count of 6 patches

  517.         if (sbr->num_patches > 5) {

  518.             av_log(ac->avctx, AV_LOG_ERROR, "Too many patches: %d\n", sbr->num_patches);

  519.             return -1;

  520.         }

  521. 

  522.         sbr->patch_num_subbands[sbr->num_patches]  = FFMAX(sb - usb, 0);

  523.         sbr->patch_start_subband[sbr->num_patches] = sbr->k[0] - odd - sbr->patch_num_subbands[sbr->num_patches];

  524. 

  525.         if (sbr->patch_num_subbands[sbr->num_patches] > 0) {

  526.             usb = sb;

  527.             msb = sb;

  528.             sbr->num_patches++;

  529.         } else

  530.             msb = sbr->kx[1];

  531. 

  532.         if (sbr->f_master[k] - sb < 3)

  533.             k = sbr->n_master;

  534.     } while (sb != sbr->kx[1] + sbr->m[1]);

  535. 

  536.     if (sbr->patch_num_subbands[sbr->num_patches-1] < 3 && sbr->num_patches > 1)

  537.         sbr->num_patches--;

  538. 

  539.     return 0;

  540. }

  541. 

  542. /// Derived Frequency Band Tables (14496-3 sp04 p197)

  543. static int sbr_make_f_derived(AACContext *ac, SpectralBandReplication *sbr)

  544. {

  545.     int k, temp;

  546. 

  547.     sbr->n[1] = sbr->n_master - sbr->spectrum_params.bs_xover_band;

  548.     sbr->n[0] = (sbr->n[1] + 1) >> 1;

  549. 

  550.     memcpy(sbr->f_tablehigh, &sbr->f_master[sbr->spectrum_params.bs_xover_band],

  551.            (sbr->n[1] + 1) * sizeof(sbr->f_master[0]));

  552.     sbr->m[1] = sbr->f_tablehigh[sbr->n[1]] - sbr->f_tablehigh[0];

  553.     sbr->kx[1] = sbr->f_tablehigh[0];

  554. 

  555.     // Requirements (14496-3 sp04 p205)

  556.     if (sbr->kx[1] + sbr->m[1] > 64) {

  557.         av_log(ac->avctx, AV_LOG_ERROR,

  558.                "Stop frequency border too high: %d\n", sbr->kx[1] + sbr->m[1]);

  559.         return -1;

  560.     }

  561.     if (sbr->kx[1] > 32) {

  562.         av_log(ac->avctx, AV_LOG_ERROR, "Start frequency border too high: %d\n", sbr->kx[1]);

  563.         return -1;

  564.     }

  565. 

  566.     sbr->f_tablelow[0] = sbr->f_tablehigh[0];

  567.     temp = sbr->n[1] & 1;

  568.     for (k = 1; k <= sbr->n[0]; k++)

  569.         sbr->f_tablelow[k] = sbr->f_tablehigh[2 * k - temp];

  570. 

  571.     sbr->n_q = FFMAX(1, lrintf(sbr->spectrum_params.bs_noise_bands *

  572.                                log2f(sbr->k[2] / (float)sbr->kx[1]))); // 0 <= bs_noise_bands <= 3

  573.     if (sbr->n_q > 5) {

  574.         av_log(ac->avctx, AV_LOG_ERROR, "Too many noise floor scale factors: %d\n", sbr->n_q);

  575.         return -1;

  576.     }

  577. 

  578.     sbr->f_tablenoise[0] = sbr->f_tablelow[0];

  579.     temp = 0;

  580.     for (k = 1; k <= sbr->n_q; k++) {

  581.         temp += (sbr->n[0] - temp) / (sbr->n_q + 1 - k);

  582.         sbr->f_tablenoise[k] = sbr->f_tablelow[temp];

  583.     }

  584. 

  585.     if (sbr_hf_calc_npatches(ac, sbr) < 0)

  586.         return -1;

  587. 

  588.     sbr_make_f_tablelim(sbr);

  589. 

  590.     sbr->data[0].f_indexnoise = 0;

  591.     sbr->data[1].f_indexnoise = 0;

  592. 

  593.     return 0;

  594. }

  595. 

  596. static av_always_inline void get_bits1_vector(GetBitContext *gb, uint8_t *vec,

  597.                                               int elements)

  598. {

  599.     int i;

  600.     for (i = 0; i < elements; i++) {

  601.         vec[i] = get_bits1(gb);

  602.     }

  603. }

  604. 

  605. /** ceil(log2(index+1)) */

  606. static const int8_t ceil_log2[] = {

  607.     0, 1, 2, 2, 3, 3,

  608. };

  609. 

  610. static int read_sbr_grid(AACContext *ac, SpectralBandReplication *sbr,

  611.                          GetBitContext *gb, SBRData *ch_data)

  612. {

  613.     int i;

  614.     unsigned bs_pointer = 0;

  615.     // frameLengthFlag ? 15 : 16; 960 sample length frames unsupported; this value is numTimeSlots

  616.     int abs_bord_trail = 16;

  617.     int num_rel_lead, num_rel_trail;

  618.     unsigned bs_num_env_old = ch_data->bs_num_env;

  619. 

  620.     ch_data->bs_freq_res[0] = ch_data->bs_freq_res[ch_data->bs_num_env];

  621.     ch_data->bs_amp_res = sbr->bs_amp_res_header;

  622.     ch_data->t_env_num_env_old = ch_data->t_env[bs_num_env_old];

  623. 

  624.     switch (ch_data->bs_frame_class = get_bits(gb, 2)) {

  625.     case FIXFIX:

  626.         ch_data->bs_num_env                 = 1 << get_bits(gb, 2);

  627.         num_rel_lead                        = ch_data->bs_num_env - 1;

  628.         if (ch_data->bs_num_env == 1)

  629.             ch_data->bs_amp_res = 0;

  630. 

  631.         if (ch_data->bs_num_env > 4) {

  632.             av_log(ac->avctx, AV_LOG_ERROR,

  633.                    "Invalid bitstream, too many SBR envelopes in FIXFIX type SBR frame: %d\n",

  634.                    ch_data->bs_num_env);

  635.             return -1;

  636.         }

  637. 

  638.         ch_data->t_env[0]                   = 0;

  639.         ch_data->t_env[ch_data->bs_num_env] = abs_bord_trail;

  640. 

  641.         abs_bord_trail = (abs_bord_trail + (ch_data->bs_num_env >> 1)) /

  642.                    ch_data->bs_num_env;

  643.         for (i = 0; i < num_rel_lead; i++)

  644.             ch_data->t_env[i + 1] = ch_data->t_env[i] + abs_bord_trail;

  645. 

  646.         ch_data->bs_freq_res[1] = get_bits1(gb);

  647.         for (i = 1; i < ch_data->bs_num_env; i++)

  648.             ch_data->bs_freq_res[i + 1] = ch_data->bs_freq_res[1];

  649.         break;

  650.     case FIXVAR:

  651.         abs_bord_trail                     += get_bits(gb, 2);

  652.         num_rel_trail                       = get_bits(gb, 2);

  653.         ch_data->bs_num_env                 = num_rel_trail + 1;

  654.         ch_data->t_env[0]                   = 0;

  655.         ch_data->t_env[ch_data->bs_num_env] = abs_bord_trail;

  656. 

  657.         for (i = 0; i < num_rel_trail; i++)

  658.             ch_data->t_env[ch_data->bs_num_env - 1 - i] =

  659.                 ch_data->t_env[ch_data->bs_num_env - i] - 2 * get_bits(gb, 2) - 2;

  660. 

  661.         bs_pointer = get_bits(gb, ceil_log2[ch_data->bs_num_env]);

  662. 

  663.         for (i = 0; i < ch_data->bs_num_env; i++)

  664.             ch_data->bs_freq_res[ch_data->bs_num_env - i] = get_bits1(gb);

  665.         break;

  666.     case VARFIX:

  667.         ch_data->t_env[0]                   = get_bits(gb, 2);

  668.         num_rel_lead                        = get_bits(gb, 2);

  669.         ch_data->bs_num_env                 = num_rel_lead + 1;

  670.         ch_data->t_env[ch_data->bs_num_env] = abs_bord_trail;

  671. 

  672.         for (i = 0; i < num_rel_lead; i++)

  673.             ch_data->t_env[i + 1] = ch_data->t_env[i] + 2 * get_bits(gb, 2) + 2;

  674. 

  675.         bs_pointer = get_bits(gb, ceil_log2[ch_data->bs_num_env]);

  676. 

  677.         get_bits1_vector(gb, ch_data->bs_freq_res + 1, ch_data->bs_num_env);

  678.         break;

  679.     case VARVAR:

  680.         ch_data->t_env[0]                   = get_bits(gb, 2);

  681.         abs_bord_trail                     += get_bits(gb, 2);

  682.         num_rel_lead                        = get_bits(gb, 2);

  683.         num_rel_trail                       = get_bits(gb, 2);

  684.         ch_data->bs_num_env                 = num_rel_lead + num_rel_trail + 1;

  685. 

  686.         if (ch_data->bs_num_env > 5) {

  687.             av_log(ac->avctx, AV_LOG_ERROR,

  688.                    "Invalid bitstream, too many SBR envelopes in VARVAR type SBR frame: %d\n",

  689.                    ch_data->bs_num_env);

  690.             return -1;

  691.         }

  692. 

  693.         ch_data->t_env[ch_data->bs_num_env] = abs_bord_trail;

  694. 

  695.         for (i = 0; i < num_rel_lead; i++)

  696.             ch_data->t_env[i + 1] = ch_data->t_env[i] + 2 * get_bits(gb, 2) + 2;

  697.         for (i = 0; i < num_rel_trail; i++)

  698.             ch_data->t_env[ch_data->bs_num_env - 1 - i] =

  699.                 ch_data->t_env[ch_data->bs_num_env - i] - 2 * get_bits(gb, 2) - 2;

  700. 

  701.         bs_pointer = get_bits(gb, ceil_log2[ch_data->bs_num_env]);

  702. 

  703.         get_bits1_vector(gb, ch_data->bs_freq_res + 1, ch_data->bs_num_env);

  704.         break;

  705.     }

  706. 

  707.     if (bs_pointer > ch_data->bs_num_env + 1) {

  708.         av_log(ac->avctx, AV_LOG_ERROR,

  709.                "Invalid bitstream, bs_pointer points to a middle noise border outside the time borders table: %d\n",

  710.                bs_pointer);

  711.         return -1;

  712.     }

  713. 

  714.     for (i = 1; i <= ch_data->bs_num_env; i++) {

  715.         if (ch_data->t_env[i-1] > ch_data->t_env[i]) {

  716.             av_log(ac->avctx, AV_LOG_ERROR, "Non monotone time borders\n");

  717.             return -1;

  718.         }

  719.     }

  720. 

  721.     ch_data->bs_num_noise = (ch_data->bs_num_env > 1) + 1;

  722. 

  723.     ch_data->t_q[0]                     = ch_data->t_env[0];

  724.     ch_data->t_q[ch_data->bs_num_noise] = ch_data->t_env[ch_data->bs_num_env];

  725.     if (ch_data->bs_num_noise > 1) {

  726.         unsigned int idx;

  727.         if (ch_data->bs_frame_class == FIXFIX) {

  728.             idx = ch_data->bs_num_env >> 1;

  729.         } else if (ch_data->bs_frame_class & 1) { // FIXVAR or VARVAR

  730.             idx = ch_data->bs_num_env - FFMAX(bs_pointer - 1, 1);

  731.         } else { // VARFIX

  732.             if (!bs_pointer)

  733.                 idx = 1;

  734.             else if (bs_pointer == 1)

  735.                 idx = ch_data->bs_num_env - 1;

  736.             else // bs_pointer > 1

  737.                 idx = bs_pointer - 1;

  738.         }

  739.         ch_data->t_q[1] = ch_data->t_env[idx];

  740.     }

  741. 

  742.     ch_data->e_a[0] = -(ch_data->e_a[1] != bs_num_env_old); // l_APrev

  743.     ch_data->e_a[1] = -1;

  744.     if ((ch_data->bs_frame_class & 1) && bs_pointer) { // FIXVAR or VARVAR and bs_pointer != 0

  745.         ch_data->e_a[1] = ch_data->bs_num_env + 1 - bs_pointer;

  746.     } else if ((ch_data->bs_frame_class == 2) && (bs_pointer > 1)) // VARFIX and bs_pointer > 1

  747.         ch_data->e_a[1] = bs_pointer - 1;

  748. 

  749.     return 0;

  750. }

  751. 

  752. static void copy_sbr_grid(SBRData *dst, const SBRData *src) {

  753.     //These variables are saved from the previous frame rather than copied

  754.     dst->bs_freq_res[0]    = dst->bs_freq_res[dst->bs_num_env];

  755.     dst->t_env_num_env_old = dst->t_env[dst->bs_num_env];

  756.     dst->e_a[0]            = -(dst->e_a[1] != dst->bs_num_env);

  757. 

  758.     //These variables are read from the bitstream and therefore copied

  759.     memcpy(dst->bs_freq_res+1, src->bs_freq_res+1, sizeof(dst->bs_freq_res)-sizeof(*dst->bs_freq_res));

  760.     memcpy(dst->t_env,         src->t_env,         sizeof(dst->t_env));

  761.     memcpy(dst->t_q,           src->t_q,           sizeof(dst->t_q));

  762.     dst->bs_num_env        = src->bs_num_env;

  763.     dst->bs_amp_res        = src->bs_amp_res;

  764.     dst->bs_num_noise      = src->bs_num_noise;

  765.     dst->bs_frame_class    = src->bs_frame_class;

  766.     dst->e_a[1]            = src->e_a[1];

  767. }

  768. 

  769. /// Read how the envelope and noise floor data is delta coded

  770. static void read_sbr_dtdf(SpectralBandReplication *sbr, GetBitContext *gb,

  771.                           SBRData *ch_data)

  772. {

  773.     get_bits1_vector(gb, ch_data->bs_df_env,   ch_data->bs_num_env);

  774.     get_bits1_vector(gb, ch_data->bs_df_noise, ch_data->bs_num_noise);

  775. }

  776. 

  777. /// Read inverse filtering data

  778. static void read_sbr_invf(SpectralBandReplication *sbr, GetBitContext *gb,

  779.                           SBRData *ch_data)

  780. {

  781.     int i;

  782. 

  783.     memcpy(ch_data->bs_invf_mode[1], ch_data->bs_invf_mode[0], 5 * sizeof(uint8_t));

  784.     for (i = 0; i < sbr->n_q; i++)

  785.         ch_data->bs_invf_mode[0][i] = get_bits(gb, 2);

  786. }

  787. 

  788. static void read_sbr_envelope(SpectralBandReplication *sbr, GetBitContext *gb,

  789.                               SBRData *ch_data, int ch)

  790. {

  791.     int bits;

  792.     int i, j, k;

  793.     VLC_TYPE (*t_huff)[2], (*f_huff)[2];

  794.     int t_lav, f_lav;

  795.     const int delta = (ch == 1 && sbr->bs_coupling == 1) + 1;

  796.     const int odd = sbr->n[1] & 1;

  797. 

  798.     if (sbr->bs_coupling && ch) {

  799.         if (ch_data->bs_amp_res) {

  800.             bits   = 5;

  801.             t_huff = vlc_sbr[T_HUFFMAN_ENV_BAL_3_0DB].table;

  802.             t_lav  = vlc_sbr_lav[T_HUFFMAN_ENV_BAL_3_0DB];

  803.             f_huff = vlc_sbr[F_HUFFMAN_ENV_BAL_3_0DB].table;

  804.             f_lav  = vlc_sbr_lav[F_HUFFMAN_ENV_BAL_3_0DB];

  805.         } else {

  806.             bits   = 6;

  807.             t_huff = vlc_sbr[T_HUFFMAN_ENV_BAL_1_5DB].table;

  808.             t_lav  = vlc_sbr_lav[T_HUFFMAN_ENV_BAL_1_5DB];

  809.             f_huff = vlc_sbr[F_HUFFMAN_ENV_BAL_1_5DB].table;

  810.             f_lav  = vlc_sbr_lav[F_HUFFMAN_ENV_BAL_1_5DB];

  811.         }

  812.     } else {

  813.         if (ch_data->bs_amp_res) {

  814.             bits   = 6;

  815.             t_huff = vlc_sbr[T_HUFFMAN_ENV_3_0DB].table;

  816.             t_lav  = vlc_sbr_lav[T_HUFFMAN_ENV_3_0DB];

  817.             f_huff = vlc_sbr[F_HUFFMAN_ENV_3_0DB].table;

  818.             f_lav  = vlc_sbr_lav[F_HUFFMAN_ENV_3_0DB];

  819.         } else {

  820.             bits   = 7;

  821.             t_huff = vlc_sbr[T_HUFFMAN_ENV_1_5DB].table;

  822.             t_lav  = vlc_sbr_lav[T_HUFFMAN_ENV_1_5DB];

  823.             f_huff = vlc_sbr[F_HUFFMAN_ENV_1_5DB].table;

  824.             f_lav  = vlc_sbr_lav[F_HUFFMAN_ENV_1_5DB];

  825.         }

  826.     }

  827. 

  828.     for (i = 0; i < ch_data->bs_num_env; i++) {

  829.         if (ch_data->bs_df_env[i]) {

  830.             // bs_freq_res[0] == bs_freq_res[bs_num_env] from prev frame

  831.             if (ch_data->bs_freq_res[i + 1] == ch_data->bs_freq_res[i]) {

  832.                 for (j = 0; j < sbr->n[ch_data->bs_freq_res[i + 1]]; j++)

  833.                     ch_data->env_facs[i + 1][j] = ch_data->env_facs[i][j] + delta * (get_vlc2(gb, t_huff, 9, 3) - t_lav);

  834.             } else if (ch_data->bs_freq_res[i + 1]) {

  835.                 for (j = 0; j < sbr->n[ch_data->bs_freq_res[i + 1]]; j++) {

  836.                     k = (j + odd) >> 1; // find k such that f_tablelow[k] <= f_tablehigh[j] < f_tablelow[k + 1]

  837.                     ch_data->env_facs[i + 1][j] = ch_data->env_facs[i][k] + delta * (get_vlc2(gb, t_huff, 9, 3) - t_lav);

  838.                 }

  839.             } else {

  840.                 for (j = 0; j < sbr->n[ch_data->bs_freq_res[i + 1]]; j++) {

  841.                     k = j ? 2*j - odd : 0; // find k such that f_tablehigh[k] == f_tablelow[j]

  842.                     ch_data->env_facs[i + 1][j] = ch_data->env_facs[i][k] + delta * (get_vlc2(gb, t_huff, 9, 3) - t_lav);

  843.                 }

  844.             }

  845.         } else {

  846.             ch_data->env_facs[i + 1][0] = delta * get_bits(gb, bits); // bs_env_start_value_balance

  847.             for (j = 1; j < sbr->n[ch_data->bs_freq_res[i + 1]]; j++)

  848.                 ch_data->env_facs[i + 1][j] = ch_data->env_facs[i + 1][j - 1] + delta * (get_vlc2(gb, f_huff, 9, 3) - f_lav);

  849.         }

  850.     }

  851. 

  852.     //assign 0th elements of env_facs from last elements

  853.     memcpy(ch_data->env_facs[0], ch_data->env_facs[ch_data->bs_num_env],

  854.            sizeof(ch_data->env_facs[0]));

  855. }

  856. 

  857. static void read_sbr_noise(SpectralBandReplication *sbr, GetBitContext *gb,

  858.                            SBRData *ch_data, int ch)

  859. {

  860.     int i, j;

  861.     VLC_TYPE (*t_huff)[2], (*f_huff)[2];

  862.     int t_lav, f_lav;

  863.     int delta = (ch == 1 && sbr->bs_coupling == 1) + 1;

  864. 

  865.     if (sbr->bs_coupling && ch) {

  866.         t_huff = vlc_sbr[T_HUFFMAN_NOISE_BAL_3_0DB].table;

  867.         t_lav  = vlc_sbr_lav[T_HUFFMAN_NOISE_BAL_3_0DB];

  868.         f_huff = vlc_sbr[F_HUFFMAN_ENV_BAL_3_0DB].table;

  869.         f_lav  = vlc_sbr_lav[F_HUFFMAN_ENV_BAL_3_0DB];

  870.     } else {

  871.         t_huff = vlc_sbr[T_HUFFMAN_NOISE_3_0DB].table;

  872.         t_lav  = vlc_sbr_lav[T_HUFFMAN_NOISE_3_0DB];

  873.         f_huff = vlc_sbr[F_HUFFMAN_ENV_3_0DB].table;

  874.         f_lav  = vlc_sbr_lav[F_HUFFMAN_ENV_3_0DB];

  875.     }

  876. 

  877.     for (i = 0; i < ch_data->bs_num_noise; i++) {

  878.         if (ch_data->bs_df_noise[i]) {

  879.             for (j = 0; j < sbr->n_q; j++)

  880.                 ch_data->noise_facs[i + 1][j] = ch_data->noise_facs[i][j] + delta * (get_vlc2(gb, t_huff, 9, 2) - t_lav);

  881.         } else {

  882.             ch_data->noise_facs[i + 1][0] = delta * get_bits(gb, 5); // bs_noise_start_value_balance or bs_noise_start_value_level

  883.             for (j = 1; j < sbr->n_q; j++)

  884.                 ch_data->noise_facs[i + 1][j] = ch_data->noise_facs[i + 1][j - 1] + delta * (get_vlc2(gb, f_huff, 9, 3) - f_lav);

  885.         }

  886.     }

  887. 

  888.     //assign 0th elements of noise_facs from last elements

  889.     memcpy(ch_data->noise_facs[0], ch_data->noise_facs[ch_data->bs_num_noise],

  890.            sizeof(ch_data->noise_facs[0]));

  891. }

  892. 

  893. static void read_sbr_extension(AACContext *ac, SpectralBandReplication *sbr,

  894.                                GetBitContext *gb,

  895.                                int bs_extension_id, int *num_bits_left)

  896. {

  897.     switch (bs_extension_id) {

  898.     case EXTENSION_ID_PS:

  899.         if (!ac->m4ac.ps) {

  900.             av_log(ac->avctx, AV_LOG_ERROR, "Parametric Stereo signaled to be not-present but was found in the bitstream.\n");

  901.             skip_bits_long(gb, *num_bits_left); // bs_fill_bits

  902.             *num_bits_left = 0;

  903.         } else {

  904. #if 1

  905.             *num_bits_left -= ff_ps_read_data(ac->avctx, gb, &sbr->ps, *num_bits_left);

  906. #else

  907.             av_log_missing_feature(ac->avctx, "Parametric Stereo is", 0);

  908.             skip_bits_long(gb, *num_bits_left); // bs_fill_bits

  909.             *num_bits_left = 0;

  910. #endif

  911.         }

  912.         break;

  913.     default:

  914.         av_log_missing_feature(ac->avctx, "Reserved SBR extensions are", 1);

  915.         skip_bits_long(gb, *num_bits_left); // bs_fill_bits

  916.         *num_bits_left = 0;

  917.         break;

  918.     }

  919. }

  920. 

  921. static int read_sbr_single_channel_element(AACContext *ac,

  922.                                             SpectralBandReplication *sbr,

  923.                                             GetBitContext *gb)

  924. {

  925.     if (get_bits1(gb)) // bs_data_extra

  926.         skip_bits(gb, 4); // bs_reserved

  927. 

  928.     if (read_sbr_grid(ac, sbr, gb, &sbr->data[0]))

  929.         return -1;

  930.     read_sbr_dtdf(sbr, gb, &sbr->data[0]);

  931.     read_sbr_invf(sbr, gb, &sbr->data[0]);

  932.     read_sbr_envelope(sbr, gb, &sbr->data[0], 0);

  933.     read_sbr_noise(sbr, gb, &sbr->data[0], 0);

  934. 

  935.     if ((sbr->data[0].bs_add_harmonic_flag = get_bits1(gb)))

  936.         get_bits1_vector(gb, sbr->data[0].bs_add_harmonic, sbr->n[1]);

  937. 

  938.     return 0;

  939. }

  940. 

  941. static int read_sbr_channel_pair_element(AACContext *ac,

  942.                                           SpectralBandReplication *sbr,

  943.                                           GetBitContext *gb)

  944. {

  945.     if (get_bits1(gb))    // bs_data_extra

  946.         skip_bits(gb, 8); // bs_reserved

  947. 

  948.     if ((sbr->bs_coupling = get_bits1(gb))) {

  949.         if (read_sbr_grid(ac, sbr, gb, &sbr->data[0]))

  950.             return -1;

  951.         copy_sbr_grid(&sbr->data[1], &sbr->data[0]);

  952.         read_sbr_dtdf(sbr, gb, &sbr->data[0]);

  953.         read_sbr_dtdf(sbr, gb, &sbr->data[1]);

  954.         read_sbr_invf(sbr, gb, &sbr->data[0]);

  955.         memcpy(sbr->data[1].bs_invf_mode[1], sbr->data[1].bs_invf_mode[0], sizeof(sbr->data[1].bs_invf_mode[0]));

  956.         memcpy(sbr->data[1].bs_invf_mode[0], sbr->data[0].bs_invf_mode[0], sizeof(sbr->data[1].bs_invf_mode[0]));

  957.         read_sbr_envelope(sbr, gb, &sbr->data[0], 0);

  958.         read_sbr_noise(sbr, gb, &sbr->data[0], 0);

  959.         read_sbr_envelope(sbr, gb, &sbr->data[1], 1);

  960.         read_sbr_noise(sbr, gb, &sbr->data[1], 1);

  961.     } else {

  962.         if (read_sbr_grid(ac, sbr, gb, &sbr->data[0]) ||

  963.             read_sbr_grid(ac, sbr, gb, &sbr->data[1]))

  964.             return -1;

  965.         read_sbr_dtdf(sbr, gb, &sbr->data[0]);

  966.         read_sbr_dtdf(sbr, gb, &sbr->data[1]);

  967.         read_sbr_invf(sbr, gb, &sbr->data[0]);

  968.         read_sbr_invf(sbr, gb, &sbr->data[1]);

  969.         read_sbr_envelope(sbr, gb, &sbr->data[0], 0);

  970.         read_sbr_envelope(sbr, gb, &sbr->data[1], 1);

  971.         read_sbr_noise(sbr, gb, &sbr->data[0], 0);

  972.         read_sbr_noise(sbr, gb, &sbr->data[1], 1);

  973.     }

  974. 

  975.     if ((sbr->data[0].bs_add_harmonic_flag = get_bits1(gb)))

  976.         get_bits1_vector(gb, sbr->data[0].bs_add_harmonic, sbr->n[1]);

  977.     if ((sbr->data[1].bs_add_harmonic_flag = get_bits1(gb)))

  978.         get_bits1_vector(gb, sbr->data[1].bs_add_harmonic, sbr->n[1]);

  979. 

  980.     return 0;

  981. }

  982. 

  983. static unsigned int read_sbr_data(AACContext *ac, SpectralBandReplication *sbr,

  984.                                   GetBitContext *gb, int id_aac)

  985. {

  986.     unsigned int cnt = get_bits_count(gb);

  987. 

  988.     if (id_aac == TYPE_SCE || id_aac == TYPE_CCE) {

  989.         if (read_sbr_single_channel_element(ac, sbr, gb)) {

  990.             sbr->start = 0;

  991.             return get_bits_count(gb) - cnt;

  992.         }

  993.     } else if (id_aac == TYPE_CPE) {

  994.         if (read_sbr_channel_pair_element(ac, sbr, gb)) {

  995.             sbr->start = 0;

  996.             return get_bits_count(gb) - cnt;

  997.         }

  998.     } else {

  999.         av_log(ac->avctx, AV_LOG_ERROR,

  1000.             "Invalid bitstream - cannot apply SBR to element type %d\n", id_aac);

  1001.         sbr->start = 0;

  1002.         return get_bits_count(gb) - cnt;

  1003.     }

  1004.     if (get_bits1(gb)) { // bs_extended_data

  1005.         int num_bits_left = get_bits(gb, 4); // bs_extension_size

  1006.         if (num_bits_left == 15)

  1007.             num_bits_left += get_bits(gb, 8); // bs_esc_count

  1008. 

  1009.         num_bits_left <<= 3;

  1010.         while (num_bits_left > 7) {

  1011.             num_bits_left -= 2;

  1012.             read_sbr_extension(ac, sbr, gb, get_bits(gb, 2), &num_bits_left); // bs_extension_id

  1013.         }

  1014.         if (num_bits_left < 0) {

  1015.             av_log(ac->avctx, AV_LOG_ERROR, "SBR Extension over read.\n");

  1016.         }

  1017.         if (num_bits_left > 0)

  1018.             skip_bits(gb, num_bits_left);

  1019.     }

  1020. 

  1021.     return get_bits_count(gb) - cnt;

  1022. }

  1023. 

  1024. static void sbr_reset(AACContext *ac, SpectralBandReplication *sbr)

  1025. {

  1026.     int err;

  1027.     err = sbr_make_f_master(ac, sbr, &sbr->spectrum_params);

  1028.     if (err >= 0)

  1029.         err = sbr_make_f_derived(ac, sbr);

  1030.     if (err < 0) {

  1031.         av_log(ac->avctx, AV_LOG_ERROR,

  1032.                "SBR reset failed. Switching SBR to pure upsampling mode.\n");

  1033.         sbr->start = 0;

  1034.     }

  1035. }

  1036. 

  1037. /**

  1038.  * Decode Spectral Band Replication extension data; reference: table 4.55.

  1039.  *

  1040.  * @param   crc flag indicating the presence of CRC checksum

  1041.  * @param   cnt length of TYPE_FIL syntactic element in bytes

  1042.  *

  1043.  * @return  Returns number of bytes consumed from the TYPE_FIL element.

  1044.  */

  1045. int ff_decode_sbr_extension(AACContext *ac, SpectralBandReplication *sbr,

  1046.                             GetBitContext *gb_host, int crc, int cnt, int id_aac)

  1047. {

  1048.     unsigned int num_sbr_bits = 0, num_align_bits;

  1049.     unsigned bytes_read;

  1050.     GetBitContext gbc = *gb_host, *gb = &gbc;

  1051.     skip_bits_long(gb_host, cnt*8 - 4);

  1052. 

  1053.     sbr->reset = 0;

  1054. 

  1055.     if (!sbr->sample_rate)

  1056.         sbr->sample_rate = 2 * ac->m4ac.sample_rate; //TODO use the nominal sample rate for arbitrary sample rate support

  1057.     if (!ac->m4ac.ext_sample_rate)

  1058.         ac->m4ac.ext_sample_rate = 2 * ac->m4ac.sample_rate;

  1059. 

  1060.     if (crc) {

  1061.         skip_bits(gb, 10); // bs_sbr_crc_bits; TODO - implement CRC check

  1062.         num_sbr_bits += 10;

  1063.     }

  1064. 

  1065.     //Save some state from the previous frame.

  1066.     sbr->kx[0] = sbr->kx[1];

  1067.     sbr->m[0] = sbr->m[1];

  1068. 

  1069.     num_sbr_bits++;

  1070.     if (get_bits1(gb)) // bs_header_flag

  1071.         num_sbr_bits += read_sbr_header(sbr, gb);

  1072. 

  1073.     if (sbr->reset)

  1074.         sbr_reset(ac, sbr);

  1075. 

  1076.     if (sbr->start)

  1077.         num_sbr_bits  += read_sbr_data(ac, sbr, gb, id_aac);

  1078. 

  1079.     num_align_bits = ((cnt << 3) - 4 - num_sbr_bits) & 7;

  1080.     bytes_read = ((num_sbr_bits + num_align_bits + 4) >> 3);

  1081. 

  1082.     if (bytes_read > cnt) {

  1083.         av_log(ac->avctx, AV_LOG_ERROR,

  1084.                "Expected to read %d SBR bytes actually read %d.\n", cnt, bytes_read);

  1085.     }

  1086.     return cnt;

  1087. }

  1088. 

  1089. /// Dequantization and stereo decoding (14496-3 sp04 p203)

  1090. static void sbr_dequant(SpectralBandReplication *sbr, int id_aac)

  1091. {

  1092.     int k, e;

  1093.     int ch;

  1094. 

  1095.     if (id_aac == TYPE_CPE && sbr->bs_coupling) {

  1096.         float alpha      = sbr->data[0].bs_amp_res ?  1.0f :  0.5f;

  1097.         float pan_offset = sbr->data[0].bs_amp_res ? 12.0f : 24.0f;

  1098.         for (e = 1; e <= sbr->data[0].bs_num_env; e++) {

  1099.             for (k = 0; k < sbr->n[sbr->data[0].bs_freq_res[e]]; k++) {

  1100.                 float temp1 = exp2f(sbr->data[0].env_facs[e][k] * alpha + 7.0f);

  1101.                 float temp2 = exp2f((pan_offset - sbr->data[1].env_facs[e][k]) * alpha);

  1102.                 float fac   = temp1 / (1.0f + temp2);

  1103.                 sbr->data[0].env_facs[e][k] = fac;

  1104.                 sbr->data[1].env_facs[e][k] = fac * temp2;

  1105.             }

  1106.         }

  1107.         for (e = 1; e <= sbr->data[0].bs_num_noise; e++) {

  1108.             for (k = 0; k < sbr->n_q; k++) {

  1109.                 float temp1 = exp2f(NOISE_FLOOR_OFFSET - sbr->data[0].noise_facs[e][k] + 1);

  1110.                 float temp2 = exp2f(12 - sbr->data[1].noise_facs[e][k]);

  1111.                 float fac   = temp1 / (1.0f + temp2);

  1112.                 sbr->data[0].noise_facs[e][k] = fac;

  1113.                 sbr->data[1].noise_facs[e][k] = fac * temp2;

  1114.             }

  1115.         }

  1116.     } else { // SCE or one non-coupled CPE

  1117.         for (ch = 0; ch < (id_aac == TYPE_CPE) + 1; ch++) {

  1118.             float alpha = sbr->data[ch].bs_amp_res ? 1.0f : 0.5f;

  1119.             for (e = 1; e <= sbr->data[ch].bs_num_env; e++)

  1120.                 for (k = 0; k < sbr->n[sbr->data[ch].bs_freq_res[e]]; k++)

  1121.                     sbr->data[ch].env_facs[e][k] =

  1122.                         exp2f(alpha * sbr->data[ch].env_facs[e][k] + 6.0f);

  1123.             for (e = 1; e <= sbr->data[ch].bs_num_noise; e++)

  1124.                 for (k = 0; k < sbr->n_q; k++)

  1125.                     sbr->data[ch].noise_facs[e][k] =

  1126.                         exp2f(NOISE_FLOOR_OFFSET - sbr->data[ch].noise_facs[e][k]);

  1127.         }

  1128.     }

  1129. }

  1130. 

  1131. /**

  1132.  * Analysis QMF Bank (14496-3 sp04 p206)

  1133.  *

  1134.  * @param   x       pointer to the beginning of the first sample window

  1135.  * @param   W       array of complex-valued samples split into subbands

  1136.  */

  1137. static void sbr_qmf_analysis(DSPContext *dsp, FFTContext *mdct, const float *in, float *x,

  1138.                              float z[320], float W[2][32][32][2])

  1139. {

  1140.     int i, k;

  1141.     memcpy(W[0], W[1], sizeof(W[0]));

  1142.     memcpy(x    , x+1024, (320-32)*sizeof(x[0]));

  1143.     memcpy(x+288, in,         1024*sizeof(x[0]));

  1144.     for (i = 0; i < 32; i++) { // numTimeSlots*RATE = 16*2 as 960 sample frames

  1145.                                // are not supported

  1146.         dsp->vector_fmul_reverse(z, sbr_qmf_window_ds, x, 320);

  1147.         for (k = 0; k < 64; k++) {

  1148.             float f = z[k] + z[k + 64] + z[k + 128] + z[k + 192] + z[k + 256];

  1149.             z[k] = f;

  1150.         }

  1151.         //Shuffle to IMDCT

  1152.         z[64] = z[0];

  1153.         for (k = 1; k < 32; k++) {

  1154.             z[64+2*k-1] =  z[   k];

  1155.             z[64+2*k  ] = -z[64-k];

  1156.         }

  1157.         z[64+63] = z[32];

  1158. 

  1159.         mdct->imdct_half(mdct, z, z+64);

  1160.         for (k = 0; k < 32; k++) {

  1161.             W[1][i][k][0] = -z[63-k];

  1162.             W[1][i][k][1] = z[k];

  1163.         }

  1164.         x += 32;

  1165.     }

  1166. }

  1167. 

  1168. /**

  1169.  * Synthesis QMF Bank (14496-3 sp04 p206) and Downsampled Synthesis QMF Bank

  1170.  * (14496-3 sp04 p206)

  1171.  */

  1172. static void sbr_qmf_synthesis(DSPContext *dsp, FFTContext *mdct,

  1173.                               float *out, float X[2][38][64],

  1174.                               float mdct_buf[2][64],

  1175.                               float *v0, int *v_off, const unsigned int div)

  1176. {

  1177.     int i, n;

  1178.     const float *sbr_qmf_window = div ? sbr_qmf_window_ds : sbr_qmf_window_us;

  1179.     float *v;

  1180.     for (i = 0; i < 32; i++) {

  1181.         if (*v_off == 0) {

  1182.             int saved_samples = (1280 - 128) >> div;

  1183.             memcpy(&v0[SBR_SYNTHESIS_BUF_SIZE - saved_samples], v0, saved_samples * sizeof(float));

  1184.             *v_off = SBR_SYNTHESIS_BUF_SIZE - saved_samples - (128 >> div);

  1185.         } else {

  1186.             *v_off -= 128 >> div;

  1187.         }

  1188.         v = v0 + *v_off;

  1189.         if (div) {

  1190.             for (n = 0; n < 32; n++) {

  1191.                 X[0][i][   n] = -X[0][i][n];

  1192.                 X[0][i][32+n] =  X[1][i][31-n];

  1193.             }

  1194.             mdct->imdct_half(mdct, mdct_buf[0], X[0][i]);

  1195.             for (n = 0; n < 32; n++) {

  1196.                 v[     n] =  mdct_buf[0][63 - 2*n];

  1197.                 v[63 - n] = -mdct_buf[0][62 - 2*n];

  1198.             }

  1199.         } else {

  1200.             for (n = 1; n < 64; n+=2) {

  1201.                 X[1][i][n] = -X[1][i][n];

  1202.             }

  1203.             mdct->imdct_half(mdct, mdct_buf[0], X[0][i]);

  1204.             mdct->imdct_half(mdct, mdct_buf[1], X[1][i]);

  1205.             for (n = 0; n < 64; n++) {

  1206.                 v[      n] = -mdct_buf[0][63 -   n] + mdct_buf[1][  n    ];

  1207.                 v[127 - n] =  mdct_buf[0][63 -   n] + mdct_buf[1][  n    ];

  1208.             }

  1209.         }

  1210.         dsp->vector_fmul_add(out, v                , sbr_qmf_window               , zero64, 64 >> div);

  1211.         dsp->vector_fmul_add(out, v + ( 192 >> div), sbr_qmf_window + ( 64 >> div), out   , 64 >> div);

  1212.         dsp->vector_fmul_add(out, v + ( 256 >> div), sbr_qmf_window + (128 >> div), out   , 64 >> div);

  1213.         dsp->vector_fmul_add(out, v + ( 448 >> div), sbr_qmf_window + (192 >> div), out   , 64 >> div);

  1214.         dsp->vector_fmul_add(out, v + ( 512 >> div), sbr_qmf_window + (256 >> div), out   , 64 >> div);

  1215.         dsp->vector_fmul_add(out, v + ( 704 >> div), sbr_qmf_window + (320 >> div), out   , 64 >> div);

  1216.         dsp->vector_fmul_add(out, v + ( 768 >> div), sbr_qmf_window + (384 >> div), out   , 64 >> div);

  1217.         dsp->vector_fmul_add(out, v + ( 960 >> div), sbr_qmf_window + (448 >> div), out   , 64 >> div);

  1218.         dsp->vector_fmul_add(out, v + (1024 >> div), sbr_qmf_window + (512 >> div), out   , 64 >> div);

  1219.         dsp->vector_fmul_add(out, v + (1216 >> div), sbr_qmf_window + (576 >> div), out   , 64 >> div);

  1220.         out += 64 >> div;

  1221.     }

  1222. }

  1223. 

  1224. static void autocorrelate(const float x[40][2], float phi[3][2][2], int lag)

  1225. {

  1226.     int i;

  1227.     float real_sum = 0.0f;

  1228.     float imag_sum = 0.0f;

  1229.     if (lag) {

  1230.         for (i = 1; i < 38; i++) {

  1231.             real_sum += x[i][0] * x[i+lag][0] + x[i][1] * x[i+lag][1];

  1232.             imag_sum += x[i][0] * x[i+lag][1] - x[i][1] * x[i+lag][0];

  1233.         }

  1234.         phi[2-lag][1][0] = real_sum + x[ 0][0] * x[lag][0] + x[ 0][1] * x[lag][1];

  1235.         phi[2-lag][1][1] = imag_sum + x[ 0][0] * x[lag][1] - x[ 0][1] * x[lag][0];

  1236.         if (lag == 1) {

  1237.             phi[0][0][0] = real_sum + x[38][0] * x[39][0] + x[38][1] * x[39][1];

  1238.             phi[0][0][1] = imag_sum + x[38][0] * x[39][1] - x[38][1] * x[39][0];

  1239.         }

  1240.     } else {

  1241.         for (i = 1; i < 38; i++) {

  1242.             real_sum += x[i][0] * x[i][0] + x[i][1] * x[i][1];

  1243.         }

  1244.         phi[2][1][0] = real_sum + x[ 0][0] * x[ 0][0] + x[ 0][1] * x[ 0][1];

  1245.         phi[1][0][0] = real_sum + x[38][0] * x[38][0] + x[38][1] * x[38][1];

  1246.     }

  1247. }

  1248. 

  1249. /** High Frequency Generation (14496-3 sp04 p214+) and Inverse Filtering

  1250.  * (14496-3 sp04 p214)

  1251.  * Warning: This routine does not seem numerically stable.

  1252.  */

  1253. static void sbr_hf_inverse_filter(float (*alpha0)[2], float (*alpha1)[2],

  1254.                                   const float X_low[32][40][2], int k0)

  1255. {

  1256.     int k;

  1257.     for (k = 0; k < k0; k++) {

  1258.         float phi[3][2][2], dk;

  1259. 

  1260.         autocorrelate(X_low[k], phi, 0);

  1261.         autocorrelate(X_low[k], phi, 1);

  1262.         autocorrelate(X_low[k], phi, 2);

  1263. 

  1264.         dk =  phi[2][1][0] * phi[1][0][0] -

  1265.              (phi[1][1][0] * phi[1][1][0] + phi[1][1][1] * phi[1][1][1]) / 1.000001f;

  1266. 

  1267.         if (!dk) {

  1268.             alpha1[k][0] = 0;

  1269.             alpha1[k][1] = 0;

  1270.         } else {

  1271.             float temp_real, temp_im;

  1272.             temp_real = phi[0][0][0] * phi[1][1][0] -

  1273.                         phi[0][0][1] * phi[1][1][1] -

  1274.                         phi[0][1][0] * phi[1][0][0];

  1275.             temp_im   = phi[0][0][0] * phi[1][1][1] +

  1276.                         phi[0][0][1] * phi[1][1][0] -

  1277.                         phi[0][1][1] * phi[1][0][0];

  1278. 

  1279.             alpha1[k][0] = temp_real / dk;

  1280.             alpha1[k][1] = temp_im   / dk;

  1281.         }

  1282. 

  1283.         if (!phi[1][0][0]) {

  1284.             alpha0[k][0] = 0;

  1285.             alpha0[k][1] = 0;

  1286.         } else {

  1287.             float temp_real, temp_im;

  1288.             temp_real = phi[0][0][0] + alpha1[k][0] * phi[1][1][0] +

  1289.                                        alpha1[k][1] * phi[1][1][1];

  1290.             temp_im   = phi[0][0][1] + alpha1[k][1] * phi[1][1][0] -

  1291.                                        alpha1[k][0] * phi[1][1][1];

  1292. 

  1293.             alpha0[k][0] = -temp_real / phi[1][0][0];

  1294.             alpha0[k][1] = -temp_im   / phi[1][0][0];

  1295.         }

  1296. 

  1297.         if (alpha1[k][0] * alpha1[k][0] + alpha1[k][1] * alpha1[k][1] >= 16.0f ||

  1298.            alpha0[k][0] * alpha0[k][0] + alpha0[k][1] * alpha0[k][1] >= 16.0f) {

  1299.             alpha1[k][0] = 0;

  1300.             alpha1[k][1] = 0;

  1301.             alpha0[k][0] = 0;

  1302.             alpha0[k][1] = 0;

  1303.         }

  1304.     }

  1305. }

  1306. 

  1307. /// Chirp Factors (14496-3 sp04 p214)

  1308. static void sbr_chirp(SpectralBandReplication *sbr, SBRData *ch_data)

  1309. {

  1310.     int i;

  1311.     float new_bw;

  1312.     static const float bw_tab[] = { 0.0f, 0.75f, 0.9f, 0.98f };

  1313. 

  1314.     for (i = 0; i < sbr->n_q; i++) {

  1315.         if (ch_data->bs_invf_mode[0][i] + ch_data->bs_invf_mode[1][i] == 1) {

  1316.             new_bw = 0.6f;

  1317.         } else

  1318.             new_bw = bw_tab[ch_data->bs_invf_mode[0][i]];

  1319. 

  1320.         if (new_bw < ch_data->bw_array[i]) {

  1321.             new_bw = 0.75f    * new_bw + 0.25f    * ch_data->bw_array[i];

  1322.         } else

  1323.             new_bw = 0.90625f * new_bw + 0.09375f * ch_data->bw_array[i];

  1324.         ch_data->bw_array[i] = new_bw < 0.015625f ? 0.0f : new_bw;

  1325.     }

  1326. }

  1327. 

  1328. /// Generate the subband filtered lowband

  1329. static int sbr_lf_gen(AACContext *ac, SpectralBandReplication *sbr,

  1330.                       float X_low[32][40][2], const float W[2][32][32][2])

  1331. {

  1332.     int i, k;

  1333.     const int t_HFGen = 8;

  1334.     const int i_f = 32;

  1335.     memset(X_low, 0, 32*sizeof(*X_low));

  1336.     for (k = 0; k < sbr->kx[1]; k++) {

  1337.         for (i = t_HFGen; i < i_f + t_HFGen; i++) {

  1338.             X_low[k][i][0] = W[1][i - t_HFGen][k][0];

  1339.             X_low[k][i][1] = W[1][i - t_HFGen][k][1];

  1340.         }

  1341.     }

  1342.     for (k = 0; k < sbr->kx[0]; k++) {

  1343.         for (i = 0; i < t_HFGen; i++) {

  1344.             X_low[k][i][0] = W[0][i + i_f - t_HFGen][k][0];

  1345.             X_low[k][i][1] = W[0][i + i_f - t_HFGen][k][1];

  1346.         }

  1347.     }

  1348.     return 0;

  1349. }

  1350. 

  1351. /// High Frequency Generator (14496-3 sp04 p215)

  1352. static int sbr_hf_gen(AACContext *ac, SpectralBandReplication *sbr,

  1353.                       float X_high[64][40][2], const float X_low[32][40][2],

  1354.                       const float (*alpha0)[2], const float (*alpha1)[2],

  1355.                       const float bw_array[5], const uint8_t *t_env,

  1356.                       int bs_num_env)

  1357. {

  1358.     int i, j, x;

  1359.     int g = 0;

  1360.     int k = sbr->kx[1];

  1361.     for (j = 0; j < sbr->num_patches; j++) {

  1362.         for (x = 0; x < sbr->patch_num_subbands[j]; x++, k++) {

  1363.             float alpha[4];

  1364.             const int p = sbr->patch_start_subband[j] + x;

  1365.             while (g <= sbr->n_q && k >= sbr->f_tablenoise[g])

  1366.                 g++;

  1367.             g--;

  1368. 

  1369.             if (g < 0) {

  1370.                 av_log(ac->avctx, AV_LOG_ERROR,

  1371.                        "ERROR : no subband found for frequency %d\n", k);

  1372.                 return -1;

  1373.             }

  1374. 

  1375.             alpha[0] = alpha1[p][0] * bw_array[g] * bw_array[g];

  1376.             alpha[1] = alpha1[p][1] * bw_array[g] * bw_array[g];

  1377.             alpha[2] = alpha0[p][0] * bw_array[g];

  1378.             alpha[3] = alpha0[p][1] * bw_array[g];

  1379. 

  1380.             for (i = 2 * t_env[0]; i < 2 * t_env[bs_num_env]; i++) {

  1381.                 const int idx = i + ENVELOPE_ADJUSTMENT_OFFSET;

  1382.                 X_high[k][idx][0] =

  1383.                     X_low[p][idx - 2][0] * alpha[0] -

  1384.                     X_low[p][idx - 2][1] * alpha[1] +

  1385.                     X_low[p][idx - 1][0] * alpha[2] -

  1386.                     X_low[p][idx - 1][1] * alpha[3] +

  1387.                     X_low[p][idx][0];

  1388.                 X_high[k][idx][1] =

  1389.                     X_low[p][idx - 2][1] * alpha[0] +

  1390.                     X_low[p][idx - 2][0] * alpha[1] +

  1391.                     X_low[p][idx - 1][1] * alpha[2] +

  1392.                     X_low[p][idx - 1][0] * alpha[3] +

  1393.                     X_low[p][idx][1];

  1394.             }

  1395.         }

  1396.     }

  1397.     if (k < sbr->m[1] + sbr->kx[1])

  1398.         memset(X_high + k, 0, (sbr->m[1] + sbr->kx[1] - k) * sizeof(*X_high));

  1399. 

  1400.     return 0;

  1401. }

  1402. 

  1403. /// Generate the subband filtered lowband

  1404. static int sbr_x_gen(SpectralBandReplication *sbr, float X[2][38][64],

  1405.                      const float X_low[32][40][2], const float Y[2][38][64][2],

  1406.                      int ch)

  1407. {

  1408.     int k, i;

  1409.     const int i_f = 32;

  1410.     const int i_Temp = FFMAX(2*sbr->data[ch].t_env_num_env_old - i_f, 0);

  1411.     memset(X, 0, 2*sizeof(*X));

  1412.     for (k = 0; k < sbr->kx[0]; k++) {

  1413.         for (i = 0; i < i_Temp; i++) {

  1414.             X[0][i][k] = X_low[k][i + ENVELOPE_ADJUSTMENT_OFFSET][0];

  1415.             X[1][i][k] = X_low[k][i + ENVELOPE_ADJUSTMENT_OFFSET][1];

  1416.         }

  1417.     }

  1418.     for (; k < sbr->kx[0] + sbr->m[0]; k++) {

  1419.         for (i = 0; i < i_Temp; i++) {

  1420.             X[0][i][k] = Y[0][i + i_f][k][0];

  1421.             X[1][i][k] = Y[0][i + i_f][k][1];

  1422.         }

  1423.     }

  1424. 

  1425.     for (k = 0; k < sbr->kx[1]; k++) {

  1426.         for (i = i_Temp; i < 38; i++) {

  1427.             X[0][i][k] = X_low[k][i + ENVELOPE_ADJUSTMENT_OFFSET][0];

  1428.             X[1][i][k] = X_low[k][i + ENVELOPE_ADJUSTMENT_OFFSET][1];

  1429.         }

  1430.     }

  1431.     for (; k < sbr->kx[1] + sbr->m[1]; k++) {

  1432.         for (i = i_Temp; i < i_f; i++) {

  1433.             X[0][i][k] = Y[1][i][k][0];

  1434.             X[1][i][k] = Y[1][i][k][1];

  1435.         }

  1436.     }

  1437.     return 0;

  1438. }

  1439. 

  1440. /** High Frequency Adjustment (14496-3 sp04 p217) and Mapping

  1441.  * (14496-3 sp04 p217)

  1442.  */

  1443. static void sbr_mapping(AACContext *ac, SpectralBandReplication *sbr,

  1444.                         SBRData *ch_data, int e_a[2])

  1445. {

  1446.     int e, i, m;

  1447. 

  1448.     memset(ch_data->s_indexmapped[1], 0, 7*sizeof(ch_data->s_indexmapped[1]));

  1449.     for (e = 0; e < ch_data->bs_num_env; e++) {

  1450.         const unsigned int ilim = sbr->n[ch_data->bs_freq_res[e + 1]];

  1451.         uint16_t *table = ch_data->bs_freq_res[e + 1] ? sbr->f_tablehigh : sbr->f_tablelow;

  1452.         int k;

  1453. 

  1454.         for (i = 0; i < ilim; i++)

  1455.             for (m = table[i]; m < table[i + 1]; m++)

  1456.                 sbr->e_origmapped[e][m - sbr->kx[1]] = ch_data->env_facs[e+1][i];

  1457. 

  1458.         // ch_data->bs_num_noise > 1 => 2 noise floors

  1459.         k = (ch_data->bs_num_noise > 1) && (ch_data->t_env[e] >= ch_data->t_q[1]);

  1460.         for (i = 0; i < sbr->n_q; i++)

  1461.             for (m = sbr->f_tablenoise[i]; m < sbr->f_tablenoise[i + 1]; m++)

  1462.                 sbr->q_mapped[e][m - sbr->kx[1]] = ch_data->noise_facs[k+1][i];

  1463. 

  1464.         for (i = 0; i < sbr->n[1]; i++) {

  1465.             if (ch_data->bs_add_harmonic_flag) {

  1466.                 const unsigned int m_midpoint =

  1467.                     (sbr->f_tablehigh[i] + sbr->f_tablehigh[i + 1]) >> 1;

  1468. 

  1469.                 ch_data->s_indexmapped[e + 1][m_midpoint - sbr->kx[1]] = ch_data->bs_add_harmonic[i] *

  1470.                     (e >= e_a[1] || (ch_data->s_indexmapped[0][m_midpoint - sbr->kx[1]] == 1));

  1471.             }

  1472.         }

  1473. 

  1474.         for (i = 0; i < ilim; i++) {

  1475.             int additional_sinusoid_present = 0;

  1476.             for (m = table[i]; m < table[i + 1]; m++) {

  1477.                 if (ch_data->s_indexmapped[e + 1][m - sbr->kx[1]]) {

  1478.                     additional_sinusoid_present = 1;

  1479.                     break;

  1480.                 }

  1481.             }

  1482.             memset(&sbr->s_mapped[e][table[i] - sbr->kx[1]], additional_sinusoid_present,

  1483.                    (table[i + 1] - table[i]) * sizeof(sbr->s_mapped[e][0]));

  1484.         }

  1485.     }

  1486. 

  1487.     memcpy(ch_data->s_indexmapped[0], ch_data->s_indexmapped[ch_data->bs_num_env], sizeof(ch_data->s_indexmapped[0]));

  1488. }

  1489. 

  1490. /// Estimation of current envelope (14496-3 sp04 p218)

  1491. static void sbr_env_estimate(float (*e_curr)[48], float X_high[64][40][2],

  1492.                              SpectralBandReplication *sbr, SBRData *ch_data)

  1493. {

  1494.     int e, i, m;

  1495. 

  1496.     if (sbr->bs_interpol_freq) {

  1497.         for (e = 0; e < ch_data->bs_num_env; e++) {

  1498.             const float recip_env_size = 0.5f / (ch_data->t_env[e + 1] - ch_data->t_env[e]);

  1499.             int ilb = ch_data->t_env[e]     * 2 + ENVELOPE_ADJUSTMENT_OFFSET;

  1500.             int iub = ch_data->t_env[e + 1] * 2 + ENVELOPE_ADJUSTMENT_OFFSET;

  1501. 

  1502.             for (m = 0; m < sbr->m[1]; m++) {

  1503.                 float sum = 0.0f;

  1504. 

  1505.                 for (i = ilb; i < iub; i++) {

  1506.                     sum += X_high[m + sbr->kx[1]][i][0] * X_high[m + sbr->kx[1]][i][0] +

  1507.                            X_high[m + sbr->kx[1]][i][1] * X_high[m + sbr->kx[1]][i][1];

  1508.                 }

  1509.                 e_curr[e][m] = sum * recip_env_size;

  1510.             }

  1511.         }

  1512.     } else {

  1513.         int k, p;

  1514. 

  1515.         for (e = 0; e < ch_data->bs_num_env; e++) {

  1516.             const int env_size = 2 * (ch_data->t_env[e + 1] - ch_data->t_env[e]);

  1517.             int ilb = ch_data->t_env[e]     * 2 + ENVELOPE_ADJUSTMENT_OFFSET;

  1518.             int iub = ch_data->t_env[e + 1] * 2 + ENVELOPE_ADJUSTMENT_OFFSET;

  1519.             const uint16_t *table = ch_data->bs_freq_res[e + 1] ? sbr->f_tablehigh : sbr->f_tablelow;

  1520. 

  1521.             for (p = 0; p < sbr->n[ch_data->bs_freq_res[e + 1]]; p++) {

  1522.                 float sum = 0.0f;

  1523.                 const int den = env_size * (table[p + 1] - table[p]);

  1524. 

  1525.                 for (k = table[p]; k < table[p + 1]; k++) {

  1526.                     for (i = ilb; i < iub; i++) {

  1527.                         sum += X_high[k][i][0] * X_high[k][i][0] +

  1528.                                X_high[k][i][1] * X_high[k][i][1];

  1529.                     }

  1530.                 }

  1531.                 sum /= den;

  1532.                 for (k = table[p]; k < table[p + 1]; k++) {

  1533.                     e_curr[e][k - sbr->kx[1]] = sum;

  1534.                 }

  1535.             }

  1536.         }

  1537.     }

  1538. }

  1539. 

  1540. /**

  1541.  * Calculation of levels of additional HF signal components (14496-3 sp04 p219)

  1542.  * and Calculation of gain (14496-3 sp04 p219)

  1543.  */

  1544. static void sbr_gain_calc(AACContext *ac, SpectralBandReplication *sbr,

  1545.                           SBRData *ch_data, const int e_a[2])

  1546. {

  1547.     int e, k, m;

  1548.     // max gain limits : -3dB, 0dB, 3dB, inf dB (limiter off)

  1549.     static const float limgain[4] = { 0.70795, 1.0, 1.41254, 10000000000 };

  1550. 

  1551.     for (e = 0; e < ch_data->bs_num_env; e++) {

  1552.         int delta = !((e == e_a[1]) || (e == e_a[0]));

  1553.         for (k = 0; k < sbr->n_lim; k++) {

  1554.             float gain_boost, gain_max;

  1555.             float sum[2] = { 0.0f, 0.0f };

  1556.             for (m = sbr->f_tablelim[k] - sbr->kx[1]; m < sbr->f_tablelim[k + 1] - sbr->kx[1]; m++) {

  1557.                 const float temp = sbr->e_origmapped[e][m] / (1.0f + sbr->q_mapped[e][m]);

  1558.                 sbr->q_m[e][m] = sqrtf(temp * sbr->q_mapped[e][m]);

  1559.                 sbr->s_m[e][m] = sqrtf(temp * ch_data->s_indexmapped[e + 1][m]);

  1560.                 if (!sbr->s_mapped[e][m]) {

  1561.                     sbr->gain[e][m] = sqrtf(sbr->e_origmapped[e][m] /

  1562.                                             ((1.0f + sbr->e_curr[e][m]) *

  1563.                                              (1.0f + sbr->q_mapped[e][m] * delta)));

  1564.                 } else {

  1565.                     sbr->gain[e][m] = sqrtf(sbr->e_origmapped[e][m] * sbr->q_mapped[e][m] /

  1566.                                             ((1.0f + sbr->e_curr[e][m]) *

  1567.                                              (1.0f + sbr->q_mapped[e][m])));

  1568.                 }

  1569.             }

  1570.             for (m = sbr->f_tablelim[k] - sbr->kx[1]; m < sbr->f_tablelim[k + 1] - sbr->kx[1]; m++) {

  1571.                 sum[0] += sbr->e_origmapped[e][m];

  1572.                 sum[1] += sbr->e_curr[e][m];

  1573.             }

  1574.             gain_max = limgain[sbr->bs_limiter_gains] * sqrtf((FLT_EPSILON + sum[0]) / (FLT_EPSILON + sum[1]));

  1575.             gain_max = FFMIN(100000.f, gain_max);

  1576.             for (m = sbr->f_tablelim[k] - sbr->kx[1]; m < sbr->f_tablelim[k + 1] - sbr->kx[1]; m++) {

  1577.                 float q_m_max   = sbr->q_m[e][m] * gain_max / sbr->gain[e][m];

  1578.                 sbr->q_m[e][m]  = FFMIN(sbr->q_m[e][m], q_m_max);

  1579.                 sbr->gain[e][m] = FFMIN(sbr->gain[e][m], gain_max);

  1580.             }

  1581.             sum[0] = sum[1] = 0.0f;

  1582.             for (m = sbr->f_tablelim[k] - sbr->kx[1]; m < sbr->f_tablelim[k + 1] - sbr->kx[1]; m++) {

  1583.                 sum[0] += sbr->e_origmapped[e][m];

  1584.                 sum[1] += sbr->e_curr[e][m] * sbr->gain[e][m] * sbr->gain[e][m]

  1585.                           + sbr->s_m[e][m] * sbr->s_m[e][m]

  1586.                           + (delta && !sbr->s_m[e][m]) * sbr->q_m[e][m] * sbr->q_m[e][m];

  1587.             }

  1588.             gain_boost = sqrtf((FLT_EPSILON + sum[0]) / (FLT_EPSILON + sum[1]));

  1589.             gain_boost = FFMIN(1.584893192f, gain_boost);

  1590.             for (m = sbr->f_tablelim[k] - sbr->kx[1]; m < sbr->f_tablelim[k + 1] - sbr->kx[1]; m++) {

  1591.                 sbr->gain[e][m] *= gain_boost;

  1592.                 sbr->q_m[e][m]  *= gain_boost;

  1593.                 sbr->s_m[e][m]  *= gain_boost;

  1594.             }

  1595.         }

  1596.     }

  1597. }

  1598. 

  1599. /// Assembling HF Signals (14496-3 sp04 p220)

  1600. static void sbr_hf_assemble(float Y[2][38][64][2], const float X_high[64][40][2],

  1601.                             SpectralBandReplication *sbr, SBRData *ch_data,

  1602.                             const int e_a[2])

  1603. {

  1604.     int e, i, j, m;

  1605.     const int h_SL = 4 * !sbr->bs_smoothing_mode;

  1606.     const int kx = sbr->kx[1];

  1607.     const int m_max = sbr->m[1];

  1608.     static const float h_smooth[5] = {

  1609.         0.33333333333333,

  1610.         0.30150283239582,

  1611.         0.21816949906249,

  1612.         0.11516383427084,

  1613.         0.03183050093751,

  1614.     };

  1615.     static const int8_t phi[2][4] = {

  1616.         {  1,  0, -1,  0}, // real

  1617.         {  0,  1,  0, -1}, // imaginary

  1618.     };

  1619.     float (*g_temp)[48] = ch_data->g_temp, (*q_temp)[48] = ch_data->q_temp;

  1620.     int indexnoise = ch_data->f_indexnoise;

  1621.     int indexsine  = ch_data->f_indexsine;

  1622.     memcpy(Y[0], Y[1], sizeof(Y[0]));

  1623. 

  1624.     if (sbr->reset) {

  1625.         for (i = 0; i < h_SL; i++) {

  1626.             memcpy(g_temp[i + 2*ch_data->t_env[0]], sbr->gain[0], m_max * sizeof(sbr->gain[0][0]));

  1627.             memcpy(q_temp[i + 2*ch_data->t_env[0]], sbr->q_m[0],  m_max * sizeof(sbr->q_m[0][0]));

  1628.         }

  1629.     } else if (h_SL) {

  1630.         memcpy(g_temp[2*ch_data->t_env[0]], g_temp[2*ch_data->t_env_num_env_old], 4*sizeof(g_temp[0]));

  1631.         memcpy(q_temp[2*ch_data->t_env[0]], q_temp[2*ch_data->t_env_num_env_old], 4*sizeof(q_temp[0]));

  1632.     }

  1633. 

  1634.     for (e = 0; e < ch_data->bs_num_env; e++) {

  1635.         for (i = 2 * ch_data->t_env[e]; i < 2 * ch_data->t_env[e + 1]; i++) {

  1636.             memcpy(g_temp[h_SL + i], sbr->gain[e], m_max * sizeof(sbr->gain[0][0]));

  1637.             memcpy(q_temp[h_SL + i], sbr->q_m[e],  m_max * sizeof(sbr->q_m[0][0]));

  1638.         }

  1639.     }

  1640. 

  1641.     for (e = 0; e < ch_data->bs_num_env; e++) {

  1642.         for (i = 2 * ch_data->t_env[e]; i < 2 * ch_data->t_env[e + 1]; i++) {

  1643.             int phi_sign = (1 - 2*(kx & 1));

  1644. 

  1645.             if (h_SL && e != e_a[0] && e != e_a[1]) {

  1646.                 for (m = 0; m < m_max; m++) {

  1647.                     const int idx1 = i + h_SL;

  1648.                     float g_filt = 0.0f;

  1649.                     for (j = 0; j <= h_SL; j++)

  1650.                         g_filt += g_temp[idx1 - j][m] * h_smooth[j];

  1651.                     Y[1][i][m + kx][0] =

  1652.                         X_high[m + kx][i + ENVELOPE_ADJUSTMENT_OFFSET][0] * g_filt;

  1653.                     Y[1][i][m + kx][1] =

  1654.                         X_high[m + kx][i + ENVELOPE_ADJUSTMENT_OFFSET][1] * g_filt;

  1655.                 }

  1656.             } else {

  1657.                 for (m = 0; m < m_max; m++) {

  1658.                     const float g_filt = g_temp[i + h_SL][m];

  1659.                     Y[1][i][m + kx][0] =

  1660.                         X_high[m + kx][i + ENVELOPE_ADJUSTMENT_OFFSET][0] * g_filt;

  1661.                     Y[1][i][m + kx][1] =

  1662.                         X_high[m + kx][i + ENVELOPE_ADJUSTMENT_OFFSET][1] * g_filt;

  1663.                 }

  1664.             }

  1665. 

  1666.             if (e != e_a[0] && e != e_a[1]) {

  1667.                 for (m = 0; m < m_max; m++) {

  1668.                     indexnoise = (indexnoise + 1) & 0x1ff;

  1669.                     if (sbr->s_m[e][m]) {

  1670.                         Y[1][i][m + kx][0] +=

  1671.                             sbr->s_m[e][m] * phi[0][indexsine];

  1672.                         Y[1][i][m + kx][1] +=

  1673.                             sbr->s_m[e][m] * (phi[1][indexsine] * phi_sign);

  1674.                     } else {

  1675.                         float q_filt;

  1676.                         if (h_SL) {

  1677.                             const int idx1 = i + h_SL;

  1678.                             q_filt = 0.0f;

  1679.                             for (j = 0; j <= h_SL; j++)

  1680.                                 q_filt += q_temp[idx1 - j][m] * h_smooth[j];

  1681.                         } else {

  1682.                             q_filt = q_temp[i][m];

  1683.                         }

  1684.                         Y[1][i][m + kx][0] +=

  1685.                             q_filt * sbr_noise_table[indexnoise][0];

  1686.                         Y[1][i][m + kx][1] +=

  1687.                             q_filt * sbr_noise_table[indexnoise][1];

  1688.                     }

  1689.                     phi_sign = -phi_sign;

  1690.                 }

  1691.             } else {

  1692.                 indexnoise = (indexnoise + m_max) & 0x1ff;

  1693.                 for (m = 0; m < m_max; m++) {

  1694.                     Y[1][i][m + kx][0] +=

  1695.                         sbr->s_m[e][m] * phi[0][indexsine];

  1696.                     Y[1][i][m + kx][1] +=

  1697.                         sbr->s_m[e][m] * (phi[1][indexsine] * phi_sign);

  1698.                     phi_sign = -phi_sign;

  1699.                 }

  1700.             }

  1701.             indexsine = (indexsine + 1) & 3;

  1702.         }

  1703.     }

  1704.     ch_data->f_indexnoise = indexnoise;

  1705.     ch_data->f_indexsine  = indexsine;

  1706. }

  1707. 

  1708. void ff_sbr_apply(AACContext *ac, SpectralBandReplication *sbr, int id_aac,

  1709.                   float* L, float* R)

  1710. {

  1711.     int downsampled = ac->m4ac.ext_sample_rate < sbr->sample_rate;

  1712.     int ch;

  1713.     int nch = (id_aac == TYPE_CPE) ? 2 : 1;

  1714. 

  1715.     if (sbr->start) {

  1716.         sbr_dequant(sbr, id_aac);

  1717.     }

  1718.     for (ch = 0; ch < nch; ch++) {

  1719.         /* decode channel */

  1720.         sbr_qmf_analysis(&ac->dsp, &sbr->mdct_ana, ch ? R : L, sbr->data[ch].analysis_filterbank_samples,

  1721.                          (float*)sbr->qmf_filter_scratch,

  1722.                          sbr->data[ch].W);

  1723.         sbr_lf_gen(ac, sbr, sbr->X_low, sbr->data[ch].W);

  1724.         if (sbr->start) {

  1725.             sbr_hf_inverse_filter(sbr->alpha0, sbr->alpha1, sbr->X_low, sbr->k[0]);

  1726.             sbr_chirp(sbr, &sbr->data[ch]);

  1727.             sbr_hf_gen(ac, sbr, sbr->X_high, sbr->X_low, sbr->alpha0, sbr->alpha1,

  1728.                        sbr->data[ch].bw_array, sbr->data[ch].t_env,

  1729.                        sbr->data[ch].bs_num_env);

  1730. 

  1731.             // hf_adj

  1732.             sbr_mapping(ac, sbr, &sbr->data[ch], sbr->data[ch].e_a);

  1733.             sbr_env_estimate(sbr->e_curr, sbr->X_high, sbr, &sbr->data[ch]);

  1734.             sbr_gain_calc(ac, sbr, &sbr->data[ch], sbr->data[ch].e_a);

  1735.             sbr_hf_assemble(sbr->data[ch].Y, sbr->X_high, sbr, &sbr->data[ch],

  1736.                             sbr->data[ch].e_a);

  1737.         }

  1738. 

  1739.         /* synthesis */

  1740.         sbr_x_gen(sbr, sbr->X[ch], sbr->X_low, sbr->data[ch].Y, ch);

  1741.     }

  1742. 

  1743.     if (ac->m4ac.ps == 1) {

  1744.         if (sbr->ps.start) {

  1745.             ff_ps_apply(ac->avctx, &sbr->ps, sbr->X[0], sbr->X[1], sbr->kx[1] + sbr->m[1]);

  1746.         } else {

  1747.             memcpy(sbr->X[1], sbr->X[0], sizeof(sbr->X[0]));

  1748.         }

  1749.         nch = 2;

  1750.     }

  1751. 

  1752.     sbr_qmf_synthesis(&ac->dsp, &sbr->mdct, L, sbr->X[0], sbr->qmf_filter_scratch,

  1753.                       sbr->data[0].synthesis_filterbank_samples,

  1754.                       &sbr->data[0].synthesis_filterbank_samples_offset,

  1755.                       downsampled);

  1756.     if (nch == 2)

  1757.         sbr_qmf_synthesis(&ac->dsp, &sbr->mdct, R, sbr->X[1], sbr->qmf_filter_scratch,

  1758.                           sbr->data[1].synthesis_filterbank_samples,

  1759.                           &sbr->data[1].synthesis_filterbank_samples_offset,

  1760.                           downsampled);

  1761. }