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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 "sbrdsp.h"

  36. #include "libavutil/libm.h"

  37. 

  38. #include <stdint.h>

  39. #include <float.h>

  40. 

  41. #define ENVELOPE_ADJUSTMENT_OFFSET 2

  42. #define NOISE_FLOOR_OFFSET 6.0f

  43. 

  44. /**

  45.  * SBR VLC tables

  46.  */

  47. enum {

  48.     T_HUFFMAN_ENV_1_5DB,

  49.     F_HUFFMAN_ENV_1_5DB,

  50.     T_HUFFMAN_ENV_BAL_1_5DB,

  51.     F_HUFFMAN_ENV_BAL_1_5DB,

  52.     T_HUFFMAN_ENV_3_0DB,

  53.     F_HUFFMAN_ENV_3_0DB,

  54.     T_HUFFMAN_ENV_BAL_3_0DB,

  55.     F_HUFFMAN_ENV_BAL_3_0DB,

  56.     T_HUFFMAN_NOISE_3_0DB,

  57.     T_HUFFMAN_NOISE_BAL_3_0DB,

  58. };

  59. 

  60. /**

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

  62.  */

  63. enum {

  64.     FIXFIX,

  65.     FIXVAR,

  66.     VARFIX,

  67.     VARVAR,

  68. };

  69. 

  70. enum {

  71.     EXTENSION_ID_PS = 2,

  72. };

  73. 

  74. static VLC vlc_sbr[10];

  75. static const int8_t vlc_sbr_lav[10] =

  76.     { 60, 60, 24, 24, 31, 31, 12, 12, 31, 12 };

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

  78. 

  79. #define SBR_INIT_VLC_STATIC(num, size) \

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

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

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

  83.                     size)

  84. 

  85. #define SBR_VLC_ROW(name) \

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

  87. 

  88. av_cold void ff_aac_sbr_init(void)

  89. {

  90.     int n;

  91.     static const struct {

  92.         const void *sbr_codes, *sbr_bits;

  93.         const unsigned int table_size, elem_size;

  94.     } sbr_tmp[] = {

  95.         SBR_VLC_ROW(t_huffman_env_1_5dB),

  96.         SBR_VLC_ROW(f_huffman_env_1_5dB),

  97.         SBR_VLC_ROW(t_huffman_env_bal_1_5dB),

  98.         SBR_VLC_ROW(f_huffman_env_bal_1_5dB),

  99.         SBR_VLC_ROW(t_huffman_env_3_0dB),

  100.         SBR_VLC_ROW(f_huffman_env_3_0dB),

  101.         SBR_VLC_ROW(t_huffman_env_bal_3_0dB),

  102.         SBR_VLC_ROW(f_huffman_env_bal_3_0dB),

  103.         SBR_VLC_ROW(t_huffman_noise_3_0dB),

  104.         SBR_VLC_ROW(t_huffman_noise_bal_3_0dB),

  105.     };

  106. 

  107.     // SBR VLC table initialization

  108.     SBR_INIT_VLC_STATIC(0, 1098);

  109.     SBR_INIT_VLC_STATIC(1, 1092);

  110.     SBR_INIT_VLC_STATIC(2, 768);

  111.     SBR_INIT_VLC_STATIC(3, 1026);

  112.     SBR_INIT_VLC_STATIC(4, 1058);

  113.     SBR_INIT_VLC_STATIC(5, 1052);

  114.     SBR_INIT_VLC_STATIC(6, 544);

  115.     SBR_INIT_VLC_STATIC(7, 544);

  116.     SBR_INIT_VLC_STATIC(8, 592);

  117.     SBR_INIT_VLC_STATIC(9, 512);

  118. 

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

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

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

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

  123. 

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

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

  126. 

  127.     ff_ps_init();

  128. }

  129. 

  130. av_cold void ff_aac_sbr_ctx_init(AACContext *ac, SpectralBandReplication *sbr)

  131. {

  132.     float mdct_scale;

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

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

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

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

  137.     /* SBR requires samples to be scaled to +/-32768.0 to work correctly.

  138.      * mdct scale factors are adjusted to scale up from +/-1.0 at analysis

  139.      * and scale back down at synthesis. */

  140.     mdct_scale = ac->avctx->sample_fmt == AV_SAMPLE_FMT_FLT ? 32768.0f : 1.0f;

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

  142.     ff_mdct_init(&sbr->mdct_ana, 7, 1, -2.0 * mdct_scale);

  143.     ff_ps_ctx_init(&sbr->ps);

  144.     ff_sbrdsp_init(&sbr->dsp);

  145. }

  146. 

  147. av_cold void ff_aac_sbr_ctx_close(SpectralBandReplication *sbr)

  148. {

  149.     ff_mdct_end(&sbr->mdct);

  150.     ff_mdct_end(&sbr->mdct_ana);

  151. }

  152. 

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

  154. {

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

  156. }

  157. 

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

  159. {

  160.     int i;

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

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

  163.             return 1;

  164.     return 0;

  165. }

  166. 

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

  168. static void sbr_make_f_tablelim(SpectralBandReplication *sbr)

  169. {

  170.     int k;

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

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

  173.                                                1.18509277094158210129f,   //2^(0.49/2)

  174.                                                1.11987160404675912501f }; //2^(0.49/3)

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

  176.         int16_t patch_borders[7];

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

  178. 

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

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

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

  182. 

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

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

  185.         if (sbr->num_patches > 1)

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

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

  188. 

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

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

  191.               qsort_comparison_function_int16);

  192. 

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

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

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

  196.                 *++out = *in++;

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

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

  199.                 in++;

  200.                 sbr->n_lim--;

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

  202.                 *out = *in++;

  203.                 sbr->n_lim--;

  204.             } else {

  205.                 *++out = *in++;

  206.             }

  207.         }

  208.     } else {

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

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

  211.         sbr->n_lim = 1;

  212.     }

  213. }

  214. 

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

  216. {

  217.     unsigned int cnt = get_bits_count(gb);

  218.     uint8_t bs_header_extra_1;

  219.     uint8_t bs_header_extra_2;

  220.     int old_bs_limiter_bands = sbr->bs_limiter_bands;

  221.     SpectrumParameters old_spectrum_params;

  222. 

  223.     sbr->start = 1;

  224. 

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

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

  227. 

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

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

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

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

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

  233. 

  234.     bs_header_extra_1 = get_bits1(gb);

  235.     bs_header_extra_2 = get_bits1(gb);

  236. 

  237.     if (bs_header_extra_1) {

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

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

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

  241.     } else {

  242.         sbr->spectrum_params.bs_freq_scale  = 2;

  243.         sbr->spectrum_params.bs_alter_scale = 1;

  244.         sbr->spectrum_params.bs_noise_bands = 2;

  245.     }

  246. 

  247.     // Check if spectrum parameters changed

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

  249.         sbr->reset = 1;

  250. 

  251.     if (bs_header_extra_2) {

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

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

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

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

  256.     } else {

  257.         sbr->bs_limiter_bands  = 2;

  258.         sbr->bs_limiter_gains  = 2;

  259.         sbr->bs_interpol_freq  = 1;

  260.         sbr->bs_smoothing_mode = 1;

  261.     }

  262. 

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

  264.         sbr_make_f_tablelim(sbr);

  265. 

  266.     return get_bits_count(gb) - cnt;

  267. }

  268. 

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

  270. {

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

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

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

  274.     return min;

  275. }

  276. 

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

  278. {

  279.     int k, previous, present;

  280.     float base, prod;

  281. 

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

  283.     prod = start;

  284.     previous = start;

  285. 

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

  287.         prod *= base;

  288.         present  = lrintf(prod);

  289.         bands[k] = present - previous;

  290.         previous = present;

  291.     }

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

  293. }

  294. 

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

  296. {

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

  298.     if (n_master <= 0) {

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

  300.         return -1;

  301.     }

  302.     if (bs_xover_band >= n_master) {

  303.         av_log(avctx, AV_LOG_ERROR,

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

  305.                bs_xover_band);

  306.         return -1;

  307.     }

  308.     return 0;

  309. }

  310. 

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

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

  313.                              SpectrumParameters *spectrum)

  314. {

  315.     unsigned int temp, max_qmf_subbands;

  316.     unsigned int start_min, stop_min;

  317.     int k;

  318.     const int8_t *sbr_offset_ptr;

  319.     int16_t stop_dk[13];

  320. 

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

  322.         temp = 3000;

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

  324.         temp = 4000;

  325.     } else

  326.         temp = 5000;

  327. 

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

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

  330. 

  331.     switch (sbr->sample_rate) {

  332.     case 16000:

  333.         sbr_offset_ptr = sbr_offset[0];

  334.         break;

  335.     case 22050:

  336.         sbr_offset_ptr = sbr_offset[1];

  337.         break;

  338.     case 24000:

  339.         sbr_offset_ptr = sbr_offset[2];

  340.         break;

  341.     case 32000:

  342.         sbr_offset_ptr = sbr_offset[3];

  343.         break;

  344.     case 44100: case 48000: case 64000:

  345.         sbr_offset_ptr = sbr_offset[4];

  346.         break;

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

  348.         sbr_offset_ptr = sbr_offset[5];

  349.         break;

  350.     default:

  351.         av_log(ac->avctx, AV_LOG_ERROR,

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

  353.         return -1;

  354.     }

  355. 

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

  357. 

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

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

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

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

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

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

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

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

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

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

  368.     } else {

  369.         av_log(ac->avctx, AV_LOG_ERROR,

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

  371.         return -1;

  372.     }

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

  374. 

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

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

  377.         max_qmf_subbands = 48;

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

  379.         max_qmf_subbands = 35;

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

  381.         max_qmf_subbands = 32;

  382. 

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

  384.         av_log(ac->avctx, AV_LOG_ERROR,

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

  386.         return -1;

  387.     }

  388. 

  389.     if (!spectrum->bs_freq_scale) {

  390.         int dk, k2diff;

  391. 

  392.         dk = spectrum->bs_alter_scale + 1;

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

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

  395.             return -1;

  396. 

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

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

  399. 

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

  401.         if (k2diff < 0) {

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

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

  404.         } else if (k2diff) {

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

  406.         }

  407. 

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

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

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

  411. 

  412.     } else {

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

  414.         int two_regions, num_bands_0;

  415.         int vdk0_max, vdk1_min;

  416.         int16_t vk0[49];

  417. 

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

  419.             two_regions = 1;

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

  421.         } else {

  422.             two_regions = 0;

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

  424.         }

  425. 

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

  427. 

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

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

  430.             return -1;

  431.         }

  432. 

  433.         vk0[0] = 0;

  434. 

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

  436. 

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

  438.         vdk0_max = vk0[num_bands_0];

  439. 

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

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

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

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

  444.                 return -1;

  445.             }

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

  447.         }

  448. 

  449.         if (two_regions) {

  450.             int16_t vk1[49];

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

  452.                                                      : 1.0f; // bs_alter_scale = {0,1}

  453.             int num_bands_1 = lrintf(half_bands * invwarp *

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

  455. 

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

  457. 

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

  459. 

  460.             if (vdk1_min < vdk0_max) {

  461.                 int change;

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

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

  464.                 vk1[1]           += change;

  465.                 vk1[num_bands_1] -= change;

  466.             }

  467. 

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

  469. 

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

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

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

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

  474.                     return -1;

  475.                 }

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

  477.             }

  478. 

  479.             sbr->n_master = num_bands_0 + num_bands_1;

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

  481.                 return -1;

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

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

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

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

  486. 

  487.         } else {

  488.             sbr->n_master = num_bands_0;

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

  490.                 return -1;

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

  492.         }

  493.     }

  494. 

  495.     return 0;

  496. }

  497. 

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

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

  500. {

  501.     int i, k, sb = 0;

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

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

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

  505. 

  506.     sbr->num_patches = 0;

  507. 

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

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

  510.     } else

  511.         k = sbr->n_master;

  512. 

  513.     do {

  514.         int odd = 0;

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

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

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

  518.         }

  519. 

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

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

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

  523.         // count of 6 patches

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

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

  526.             return -1;

  527.         }

  528. 

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

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

  531. 

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

  533.             usb = sb;

  534.             msb = sb;

  535.             sbr->num_patches++;

  536.         } else

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

  538. 

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

  540.             k = sbr->n_master;

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

  542. 

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

  544.         sbr->num_patches--;

  545. 

  546.     return 0;

  547. }

  548. 

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

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

  551. {

  552.     int k, temp;

  553. 

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

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

  556. 

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

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

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

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

  561. 

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

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

  564.         av_log(ac->avctx, AV_LOG_ERROR,

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

  566.         return -1;

  567.     }

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

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

  570.         return -1;

  571.     }

  572. 

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

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

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

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

  577. 

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

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

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

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

  582.         return -1;

  583.     }

  584. 

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

  586.     temp = 0;

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

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

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

  590.     }

  591. 

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

  593.         return -1;

  594. 

  595.     sbr_make_f_tablelim(sbr);

  596. 

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

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

  599. 

  600.     return 0;

  601. }

  602. 

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

  604.                                               int elements)

  605. {

  606.     int i;

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

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

  609.     }

  610. }

  611. 

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

  613. static const int8_t ceil_log2[] = {

  614.     0, 1, 2, 2, 3, 3,

  615. };

  616. 

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

  618.                          GetBitContext *gb, SBRData *ch_data)

  619. {

  620.     int i;

  621.     unsigned bs_pointer = 0;

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

  623.     int abs_bord_trail = 16;

  624.     int num_rel_lead, num_rel_trail;

  625.     unsigned bs_num_env_old = ch_data->bs_num_env;

  626. 

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

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

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

  630. 

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

  632.     case FIXFIX:

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

  634.         num_rel_lead                        = ch_data->bs_num_env - 1;

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

  636.             ch_data->bs_amp_res = 0;

  637. 

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

  639.             av_log(ac->avctx, AV_LOG_ERROR,

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

  641.                    ch_data->bs_num_env);

  642.             return -1;

  643.         }

  644. 

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

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

  647. 

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

  649.                    ch_data->bs_num_env;

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

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

  652. 

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

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

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

  656.         break;

  657.     case FIXVAR:

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

  659.         num_rel_trail                       = get_bits(gb, 2);

  660.         ch_data->bs_num_env                 = num_rel_trail + 1;

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

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

  663. 

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

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

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

  667. 

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

  669. 

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

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

  672.         break;

  673.     case VARFIX:

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

  675.         num_rel_lead                        = get_bits(gb, 2);

  676.         ch_data->bs_num_env                 = num_rel_lead + 1;

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

  678. 

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

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

  681. 

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

  683. 

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

  685.         break;

  686.     case VARVAR:

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

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

  689.         num_rel_lead                        = get_bits(gb, 2);

  690.         num_rel_trail                       = get_bits(gb, 2);

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

  692. 

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

  694.             av_log(ac->avctx, AV_LOG_ERROR,

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

  696.                    ch_data->bs_num_env);

  697.             return -1;

  698.         }

  699. 

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

  701. 

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

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

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

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

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

  707. 

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

  709. 

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

  711.         break;

  712.     }

  713. 

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

  715.         av_log(ac->avctx, AV_LOG_ERROR,

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

  717.                bs_pointer);

  718.         return -1;

  719.     }

  720. 

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

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

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

  724.             return -1;

  725.         }

  726.     }

  727. 

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

  729. 

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

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

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

  733.         unsigned int idx;

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

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

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

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

  738.         } else { // VARFIX

  739.             if (!bs_pointer)

  740.                 idx = 1;

  741.             else if (bs_pointer == 1)

  742.                 idx = ch_data->bs_num_env - 1;

  743.             else // bs_pointer > 1

  744.                 idx = bs_pointer - 1;

  745.         }

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

  747.     }

  748. 

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

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

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

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

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

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

  755. 

  756.     return 0;

  757. }

  758. 

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

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

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

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

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

  764. 

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

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

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

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

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

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

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

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

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

  774. }

  775. 

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

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

  778.                           SBRData *ch_data)

  779. {

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

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

  782. }

  783. 

  784. /// Read inverse filtering data

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

  786.                           SBRData *ch_data)

  787. {

  788.     int i;

  789. 

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

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

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

  793. }

  794. 

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

  796.                               SBRData *ch_data, int ch)

  797. {

  798.     int bits;

  799.     int i, j, k;

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

  801.     int t_lav, f_lav;

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

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

  804. 

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

  806.         if (ch_data->bs_amp_res) {

  807.             bits   = 5;

  808.             t_huff = vlc_sbr[T_HUFFMAN_ENV_BAL_3_0DB].table;

  809.             t_lav  = vlc_sbr_lav[T_HUFFMAN_ENV_BAL_3_0DB];

  810.             f_huff = vlc_sbr[F_HUFFMAN_ENV_BAL_3_0DB].table;

  811.             f_lav  = vlc_sbr_lav[F_HUFFMAN_ENV_BAL_3_0DB];

  812.         } else {

  813.             bits   = 6;

  814.             t_huff = vlc_sbr[T_HUFFMAN_ENV_BAL_1_5DB].table;

  815.             t_lav  = vlc_sbr_lav[T_HUFFMAN_ENV_BAL_1_5DB];

  816.             f_huff = vlc_sbr[F_HUFFMAN_ENV_BAL_1_5DB].table;

  817.             f_lav  = vlc_sbr_lav[F_HUFFMAN_ENV_BAL_1_5DB];

  818.         }

  819.     } else {

  820.         if (ch_data->bs_amp_res) {

  821.             bits   = 6;

  822.             t_huff = vlc_sbr[T_HUFFMAN_ENV_3_0DB].table;

  823.             t_lav  = vlc_sbr_lav[T_HUFFMAN_ENV_3_0DB];

  824.             f_huff = vlc_sbr[F_HUFFMAN_ENV_3_0DB].table;

  825.             f_lav  = vlc_sbr_lav[F_HUFFMAN_ENV_3_0DB];

  826.         } else {

  827.             bits   = 7;

  828.             t_huff = vlc_sbr[T_HUFFMAN_ENV_1_5DB].table;

  829.             t_lav  = vlc_sbr_lav[T_HUFFMAN_ENV_1_5DB];

  830.             f_huff = vlc_sbr[F_HUFFMAN_ENV_1_5DB].table;

  831.             f_lav  = vlc_sbr_lav[F_HUFFMAN_ENV_1_5DB];

  832.         }

  833.     }

  834. 

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

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

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

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

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

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

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

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

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

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

  845.                 }

  846.             } else {

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

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

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

  850.                 }

  851.             }

  852.         } else {

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

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

  855.                 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);

  856.         }

  857.     }

  858. 

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

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

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

  862. }

  863. 

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

  865.                            SBRData *ch_data, int ch)

  866. {

  867.     int i, j;

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

  869.     int t_lav, f_lav;

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

  871. 

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

  873.         t_huff = vlc_sbr[T_HUFFMAN_NOISE_BAL_3_0DB].table;

  874.         t_lav  = vlc_sbr_lav[T_HUFFMAN_NOISE_BAL_3_0DB];

  875.         f_huff = vlc_sbr[F_HUFFMAN_ENV_BAL_3_0DB].table;

  876.         f_lav  = vlc_sbr_lav[F_HUFFMAN_ENV_BAL_3_0DB];

  877.     } else {

  878.         t_huff = vlc_sbr[T_HUFFMAN_NOISE_3_0DB].table;

  879.         t_lav  = vlc_sbr_lav[T_HUFFMAN_NOISE_3_0DB];

  880.         f_huff = vlc_sbr[F_HUFFMAN_ENV_3_0DB].table;

  881.         f_lav  = vlc_sbr_lav[F_HUFFMAN_ENV_3_0DB];

  882.     }

  883. 

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

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

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

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

  888.         } else {

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

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

  891.                 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);

  892.         }

  893.     }

  894. 

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

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

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

  898. }

  899. 

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

  901.                                GetBitContext *gb,

  902.                                int bs_extension_id, int *num_bits_left)

  903. {

  904.     switch (bs_extension_id) {

  905.     case EXTENSION_ID_PS:

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

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

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

  909.             *num_bits_left = 0;

  910.         } else {

  911. #if 1

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

  913. #else

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

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

  916.             *num_bits_left = 0;

  917. #endif

  918.         }

  919.         break;

  920.     default:

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

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

  923.         *num_bits_left = 0;

  924.         break;

  925.     }

  926. }

  927. 

  928. static int read_sbr_single_channel_element(AACContext *ac,

  929.                                             SpectralBandReplication *sbr,

  930.                                             GetBitContext *gb)

  931. {

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

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

  934. 

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

  936.         return -1;

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

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

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

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

  941. 

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

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

  944. 

  945.     return 0;

  946. }

  947. 

  948. static int read_sbr_channel_pair_element(AACContext *ac,

  949.                                           SpectralBandReplication *sbr,

  950.                                           GetBitContext *gb)

  951. {

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

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

  954. 

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

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

  957.             return -1;

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

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

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

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

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

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

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

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

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

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

  968.     } else {

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

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

  971.             return -1;

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

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

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

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

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

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

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

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

  980.     }

  981. 

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

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

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

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

  986. 

  987.     return 0;

  988. }

  989. 

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

  991.                                   GetBitContext *gb, int id_aac)

  992. {

  993.     unsigned int cnt = get_bits_count(gb);

  994. 

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

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

  997.             sbr->start = 0;

  998.             return get_bits_count(gb) - cnt;

  999.         }

  1000.     } else if (id_aac == TYPE_CPE) {

  1001.         if (read_sbr_channel_pair_element(ac, sbr, gb)) {

  1002.             sbr->start = 0;

  1003.             return get_bits_count(gb) - cnt;

  1004.         }

  1005.     } else {

  1006.         av_log(ac->avctx, AV_LOG_ERROR,

  1007.             "Invalid bitstream - cannot apply SBR to element type %d\n", id_aac);

  1008.         sbr->start = 0;

  1009.         return get_bits_count(gb) - cnt;

  1010.     }

  1011.     if (get_bits1(gb)) { // bs_extended_data

  1012.         int num_bits_left = get_bits(gb, 4); // bs_extension_size

  1013.         if (num_bits_left == 15)

  1014.             num_bits_left += get_bits(gb, 8); // bs_esc_count

  1015. 

  1016.         num_bits_left <<= 3;

  1017.         while (num_bits_left > 7) {

  1018.             num_bits_left -= 2;

  1019.             read_sbr_extension(ac, sbr, gb, get_bits(gb, 2), &num_bits_left); // bs_extension_id

  1020.         }

  1021.         if (num_bits_left < 0) {

  1022.             av_log(ac->avctx, AV_LOG_ERROR, "SBR Extension over read.\n");

  1023.         }

  1024.         if (num_bits_left > 0)

  1025.             skip_bits(gb, num_bits_left);

  1026.     }

  1027. 

  1028.     return get_bits_count(gb) - cnt;

  1029. }

  1030. 

  1031. static void sbr_reset(AACContext *ac, SpectralBandReplication *sbr)

  1032. {

  1033.     int err;

  1034.     err = sbr_make_f_master(ac, sbr, &sbr->spectrum_params);

  1035.     if (err >= 0)

  1036.         err = sbr_make_f_derived(ac, sbr);

  1037.     if (err < 0) {

  1038.         av_log(ac->avctx, AV_LOG_ERROR,

  1039.                "SBR reset failed. Switching SBR to pure upsampling mode.\n");

  1040.         sbr->start = 0;

  1041.     }

  1042. }

  1043. 

  1044. /**

  1045.  * Decode Spectral Band Replication extension data; reference: table 4.55.

  1046.  *

  1047.  * @param   crc flag indicating the presence of CRC checksum

  1048.  * @param   cnt length of TYPE_FIL syntactic element in bytes

  1049.  *

  1050.  * @return  Returns number of bytes consumed from the TYPE_FIL element.

  1051.  */

  1052. int ff_decode_sbr_extension(AACContext *ac, SpectralBandReplication *sbr,

  1053.                             GetBitContext *gb_host, int crc, int cnt, int id_aac)

  1054. {

  1055.     unsigned int num_sbr_bits = 0, num_align_bits;

  1056.     unsigned bytes_read;

  1057.     GetBitContext gbc = *gb_host, *gb = &gbc;

  1058.     skip_bits_long(gb_host, cnt*8 - 4);

  1059. 

  1060.     sbr->reset = 0;

  1061. 

  1062.     if (!sbr->sample_rate)

  1063.         sbr->sample_rate = 2 * ac->m4ac.sample_rate; //TODO use the nominal sample rate for arbitrary sample rate support

  1064.     if (!ac->m4ac.ext_sample_rate)

  1065.         ac->m4ac.ext_sample_rate = 2 * ac->m4ac.sample_rate;

  1066. 

  1067.     if (crc) {

  1068.         skip_bits(gb, 10); // bs_sbr_crc_bits; TODO - implement CRC check

  1069.         num_sbr_bits += 10;

  1070.     }

  1071. 

  1072.     //Save some state from the previous frame.

  1073.     sbr->kx[0] = sbr->kx[1];

  1074.     sbr->m[0] = sbr->m[1];

  1075. 

  1076.     num_sbr_bits++;

  1077.     if (get_bits1(gb)) // bs_header_flag

  1078.         num_sbr_bits += read_sbr_header(sbr, gb);

  1079. 

  1080.     if (sbr->reset)

  1081.         sbr_reset(ac, sbr);

  1082. 

  1083.     if (sbr->start)

  1084.         num_sbr_bits  += read_sbr_data(ac, sbr, gb, id_aac);

  1085. 

  1086.     num_align_bits = ((cnt << 3) - 4 - num_sbr_bits) & 7;

  1087.     bytes_read = ((num_sbr_bits + num_align_bits + 4) >> 3);

  1088. 

  1089.     if (bytes_read > cnt) {

  1090.         av_log(ac->avctx, AV_LOG_ERROR,

  1091.                "Expected to read %d SBR bytes actually read %d.\n", cnt, bytes_read);

  1092.     }

  1093.     return cnt;

  1094. }

  1095. 

  1096. /// Dequantization and stereo decoding (14496-3 sp04 p203)

  1097. static void sbr_dequant(SpectralBandReplication *sbr, int id_aac)

  1098. {

  1099.     int k, e;

  1100.     int ch;

  1101. 

  1102.     if (id_aac == TYPE_CPE && sbr->bs_coupling) {

  1103.         float alpha      = sbr->data[0].bs_amp_res ?  1.0f :  0.5f;

  1104.         float pan_offset = sbr->data[0].bs_amp_res ? 12.0f : 24.0f;

  1105.         for (e = 1; e <= sbr->data[0].bs_num_env; e++) {

  1106.             for (k = 0; k < sbr->n[sbr->data[0].bs_freq_res[e]]; k++) {

  1107.                 float temp1 = exp2f(sbr->data[0].env_facs[e][k] * alpha + 7.0f);

  1108.                 float temp2 = exp2f((pan_offset - sbr->data[1].env_facs[e][k]) * alpha);

  1109.                 float fac   = temp1 / (1.0f + temp2);

  1110.                 sbr->data[0].env_facs[e][k] = fac;

  1111.                 sbr->data[1].env_facs[e][k] = fac * temp2;

  1112.             }

  1113.         }

  1114.         for (e = 1; e <= sbr->data[0].bs_num_noise; e++) {

  1115.             for (k = 0; k < sbr->n_q; k++) {

  1116.                 float temp1 = exp2f(NOISE_FLOOR_OFFSET - sbr->data[0].noise_facs[e][k] + 1);

  1117.                 float temp2 = exp2f(12 - sbr->data[1].noise_facs[e][k]);

  1118.                 float fac   = temp1 / (1.0f + temp2);

  1119.                 sbr->data[0].noise_facs[e][k] = fac;

  1120.                 sbr->data[1].noise_facs[e][k] = fac * temp2;

  1121.             }

  1122.         }

  1123.     } else { // SCE or one non-coupled CPE

  1124.         for (ch = 0; ch < (id_aac == TYPE_CPE) + 1; ch++) {

  1125.             float alpha = sbr->data[ch].bs_amp_res ? 1.0f : 0.5f;

  1126.             for (e = 1; e <= sbr->data[ch].bs_num_env; e++)

  1127.                 for (k = 0; k < sbr->n[sbr->data[ch].bs_freq_res[e]]; k++)

  1128.                     sbr->data[ch].env_facs[e][k] =

  1129.                         exp2f(alpha * sbr->data[ch].env_facs[e][k] + 6.0f);

  1130.             for (e = 1; e <= sbr->data[ch].bs_num_noise; e++)

  1131.                 for (k = 0; k < sbr->n_q; k++)

  1132.                     sbr->data[ch].noise_facs[e][k] =

  1133.                         exp2f(NOISE_FLOOR_OFFSET - sbr->data[ch].noise_facs[e][k]);

  1134.         }

  1135.     }

  1136. }

  1137. 

  1138. /**

  1139.  * Analysis QMF Bank (14496-3 sp04 p206)

  1140.  *

  1141.  * @param   x       pointer to the beginning of the first sample window

  1142.  * @param   W       array of complex-valued samples split into subbands

  1143.  */

  1144. static void sbr_qmf_analysis(DSPContext *dsp, FFTContext *mdct,

  1145.                              SBRDSPContext *sbrdsp, const float *in, float *x,

  1146.                              float z[320], float W[2][32][32][2])

  1147. {

  1148.     int i;

  1149.     memcpy(W[0], W[1], sizeof(W[0]));

  1150.     memcpy(x    , x+1024, (320-32)*sizeof(x[0]));

  1151.     memcpy(x+288, in,         1024*sizeof(x[0]));

  1152.     for (i = 0; i < 32; i++) { // numTimeSlots*RATE = 16*2 as 960 sample frames

  1153.                                // are not supported

  1154.         dsp->vector_fmul_reverse(z, sbr_qmf_window_ds, x, 320);

  1155.         sbrdsp->sum64x5(z);

  1156.         sbrdsp->qmf_pre_shuffle(z);

  1157.         mdct->imdct_half(mdct, z, z+64);

  1158.         sbrdsp->qmf_post_shuffle(W[1][i], z);

  1159.         x += 32;

  1160.     }

  1161. }

  1162. 

  1163. /**

  1164.  * Synthesis QMF Bank (14496-3 sp04 p206) and Downsampled Synthesis QMF Bank

  1165.  * (14496-3 sp04 p206)

  1166.  */

  1167. static void sbr_qmf_synthesis(DSPContext *dsp, FFTContext *mdct,

  1168.                               SBRDSPContext *sbrdsp,

  1169.                               float *out, float X[2][38][64],

  1170.                               float mdct_buf[2][64],

  1171.                               float *v0, int *v_off, const unsigned int div)

  1172. {

  1173.     int i, n;

  1174.     const float *sbr_qmf_window = div ? sbr_qmf_window_ds : sbr_qmf_window_us;

  1175.     const int step = 128 >> div;

  1176.     float *v;

  1177.     for (i = 0; i < 32; i++) {

  1178.         if (*v_off < step) {

  1179.             int saved_samples = (1280 - 128) >> div;

  1180.             memcpy(&v0[SBR_SYNTHESIS_BUF_SIZE - saved_samples], v0, saved_samples * sizeof(float));

  1181.             *v_off = SBR_SYNTHESIS_BUF_SIZE - saved_samples - step;

  1182.         } else {

  1183.             *v_off -= step;

  1184.         }

  1185.         v = v0 + *v_off;

  1186.         if (div) {

  1187.             for (n = 0; n < 32; n++) {

  1188.                 X[0][i][   n] = -X[0][i][n];

  1189.                 X[0][i][32+n] =  X[1][i][31-n];

  1190.             }

  1191.             mdct->imdct_half(mdct, mdct_buf[0], X[0][i]);

  1192.             sbrdsp->qmf_deint_neg(v, mdct_buf[0]);

  1193.         } else {

  1194.             sbrdsp->neg_odd_64(X[1][i]);

  1195.             mdct->imdct_half(mdct, mdct_buf[0], X[0][i]);

  1196.             mdct->imdct_half(mdct, mdct_buf[1], X[1][i]);

  1197.             sbrdsp->qmf_deint_bfly(v, mdct_buf[1], mdct_buf[0]);

  1198.         }

  1199.         dsp->vector_fmul_add(out, v                , sbr_qmf_window               , zero64, 64 >> div);

  1200.         dsp->vector_fmul_add(out, v + ( 192 >> div), sbr_qmf_window + ( 64 >> div), out   , 64 >> div);

  1201.         dsp->vector_fmul_add(out, v + ( 256 >> div), sbr_qmf_window + (128 >> div), out   , 64 >> div);

  1202.         dsp->vector_fmul_add(out, v + ( 448 >> div), sbr_qmf_window + (192 >> div), out   , 64 >> div);

  1203.         dsp->vector_fmul_add(out, v + ( 512 >> div), sbr_qmf_window + (256 >> div), out   , 64 >> div);

  1204.         dsp->vector_fmul_add(out, v + ( 704 >> div), sbr_qmf_window + (320 >> div), out   , 64 >> div);

  1205.         dsp->vector_fmul_add(out, v + ( 768 >> div), sbr_qmf_window + (384 >> div), out   , 64 >> div);

  1206.         dsp->vector_fmul_add(out, v + ( 960 >> div), sbr_qmf_window + (448 >> div), out   , 64 >> div);

  1207.         dsp->vector_fmul_add(out, v + (1024 >> div), sbr_qmf_window + (512 >> div), out   , 64 >> div);

  1208.         dsp->vector_fmul_add(out, v + (1216 >> div), sbr_qmf_window + (576 >> div), out   , 64 >> div);

  1209.         out += 64 >> div;

  1210.     }

  1211. }

  1212. 

  1213. /** High Frequency Generation (14496-3 sp04 p214+) and Inverse Filtering

  1214.  * (14496-3 sp04 p214)

  1215.  * Warning: This routine does not seem numerically stable.

  1216.  */

  1217. static void sbr_hf_inverse_filter(SBRDSPContext *dsp,

  1218.                                   float (*alpha0)[2], float (*alpha1)[2],

  1219.                                   const float X_low[32][40][2], int k0)

  1220. {

  1221.     int k;

  1222.     for (k = 0; k < k0; k++) {

  1223.         LOCAL_ALIGNED_16(float, phi, [3], [2][2]);

  1224.         float dk;

  1225. 

  1226.         dsp->autocorrelate(X_low[k], phi);

  1227. 

  1228.         dk =  phi[2][1][0] * phi[1][0][0] -

  1229.              (phi[1][1][0] * phi[1][1][0] + phi[1][1][1] * phi[1][1][1]) / 1.000001f;

  1230. 

  1231.         if (!dk) {

  1232.             AV_ZERO64(alpha1[k]);

  1233.         } else {

  1234.             float temp_real, temp_im;

  1235.             temp_real = phi[0][0][0] * phi[1][1][0] -

  1236.                         phi[0][0][1] * phi[1][1][1] -

  1237.                         phi[0][1][0] * phi[1][0][0];

  1238.             temp_im   = phi[0][0][0] * phi[1][1][1] +

  1239.                         phi[0][0][1] * phi[1][1][0] -

  1240.                         phi[0][1][1] * phi[1][0][0];

  1241. 

  1242.             alpha1[k][0] = temp_real / dk;

  1243.             alpha1[k][1] = temp_im   / dk;

  1244.         }

  1245. 

  1246.         if (!phi[1][0][0]) {

  1247.             AV_ZERO64(alpha0[k]);

  1248.         } else {

  1249.             float temp_real, temp_im;

  1250.             temp_real = phi[0][0][0] + alpha1[k][0] * phi[1][1][0] +

  1251.                                        alpha1[k][1] * phi[1][1][1];

  1252.             temp_im   = phi[0][0][1] + alpha1[k][1] * phi[1][1][0] -

  1253.                                        alpha1[k][0] * phi[1][1][1];

  1254. 

  1255.             alpha0[k][0] = -temp_real / phi[1][0][0];

  1256.             alpha0[k][1] = -temp_im   / phi[1][0][0];

  1257.         }

  1258. 

  1259.         if (alpha1[k][0] * alpha1[k][0] + alpha1[k][1] * alpha1[k][1] >= 16.0f ||

  1260.            alpha0[k][0] * alpha0[k][0] + alpha0[k][1] * alpha0[k][1] >= 16.0f) {

  1261.             AV_ZERO64(alpha0[k]);

  1262.             AV_ZERO64(alpha1[k]);

  1263.         }

  1264.     }

  1265. }

  1266. 

  1267. /// Chirp Factors (14496-3 sp04 p214)

  1268. static void sbr_chirp(SpectralBandReplication *sbr, SBRData *ch_data)

  1269. {

  1270.     int i;

  1271.     float new_bw;

  1272.     static const float bw_tab[] = { 0.0f, 0.75f, 0.9f, 0.98f };

  1273. 

  1274.     for (i = 0; i < sbr->n_q; i++) {

  1275.         if (ch_data->bs_invf_mode[0][i] + ch_data->bs_invf_mode[1][i] == 1) {

  1276.             new_bw = 0.6f;

  1277.         } else

  1278.             new_bw = bw_tab[ch_data->bs_invf_mode[0][i]];

  1279. 

  1280.         if (new_bw < ch_data->bw_array[i]) {

  1281.             new_bw = 0.75f    * new_bw + 0.25f    * ch_data->bw_array[i];

  1282.         } else

  1283.             new_bw = 0.90625f * new_bw + 0.09375f * ch_data->bw_array[i];

  1284.         ch_data->bw_array[i] = new_bw < 0.015625f ? 0.0f : new_bw;

  1285.     }

  1286. }

  1287. 

  1288. /// Generate the subband filtered lowband

  1289. static int sbr_lf_gen(AACContext *ac, SpectralBandReplication *sbr,

  1290.                       float X_low[32][40][2], const float W[2][32][32][2])

  1291. {

  1292.     int i, k;

  1293.     const int t_HFGen = 8;

  1294.     const int i_f = 32;

  1295.     memset(X_low, 0, 32*sizeof(*X_low));

  1296.     for (k = 0; k < sbr->kx[1]; k++) {

  1297.         for (i = t_HFGen; i < i_f + t_HFGen; i++) {

  1298.             AV_COPY64(X_low[k][i], W[1][i - t_HFGen][k]);

  1299.         }

  1300.     }

  1301.     for (k = 0; k < sbr->kx[0]; k++) {

  1302.         for (i = 0; i < t_HFGen; i++) {

  1303.             AV_COPY64(X_low[k][i], W[0][i + i_f - t_HFGen][k]);

  1304.         }

  1305.     }

  1306.     return 0;

  1307. }

  1308. 

  1309. /// High Frequency Generator (14496-3 sp04 p215)

  1310. static int sbr_hf_gen(AACContext *ac, SpectralBandReplication *sbr,

  1311.                       float X_high[64][40][2], const float X_low[32][40][2],

  1312.                       const float (*alpha0)[2], const float (*alpha1)[2],

  1313.                       const float bw_array[5], const uint8_t *t_env,

  1314.                       int bs_num_env)

  1315. {

  1316.     int j, x;

  1317.     int g = 0;

  1318.     int k = sbr->kx[1];

  1319.     for (j = 0; j < sbr->num_patches; j++) {

  1320.         for (x = 0; x < sbr->patch_num_subbands[j]; x++, k++) {

  1321.             const int p = sbr->patch_start_subband[j] + x;

  1322.             while (g <= sbr->n_q && k >= sbr->f_tablenoise[g])

  1323.                 g++;

  1324.             g--;

  1325. 

  1326.             if (g < 0) {

  1327.                 av_log(ac->avctx, AV_LOG_ERROR,

  1328.                        "ERROR : no subband found for frequency %d\n", k);

  1329.                 return -1;

  1330.             }

  1331. 

  1332.             sbr->dsp.hf_gen(X_high[k] + ENVELOPE_ADJUSTMENT_OFFSET,

  1333.                             X_low[p]  + ENVELOPE_ADJUSTMENT_OFFSET,

  1334.                             alpha0[p], alpha1[p], bw_array[g],

  1335.                             2 * t_env[0], 2 * t_env[bs_num_env]);

  1336.         }

  1337.     }

  1338.     if (k < sbr->m[1] + sbr->kx[1])

  1339.         memset(X_high + k, 0, (sbr->m[1] + sbr->kx[1] - k) * sizeof(*X_high));

  1340. 

  1341.     return 0;

  1342. }

  1343. 

  1344. /// Generate the subband filtered lowband

  1345. static int sbr_x_gen(SpectralBandReplication *sbr, float X[2][38][64],

  1346.                      const float Y0[38][64][2], const float Y1[38][64][2],

  1347.                      const float X_low[32][40][2], int ch)

  1348. {

  1349.     int k, i;

  1350.     const int i_f = 32;

  1351.     const int i_Temp = FFMAX(2*sbr->data[ch].t_env_num_env_old - i_f, 0);

  1352.     memset(X, 0, 2*sizeof(*X));

  1353.     for (k = 0; k < sbr->kx[0]; k++) {

  1354.         for (i = 0; i < i_Temp; i++) {

  1355.             X[0][i][k] = X_low[k][i + ENVELOPE_ADJUSTMENT_OFFSET][0];

  1356.             X[1][i][k] = X_low[k][i + ENVELOPE_ADJUSTMENT_OFFSET][1];

  1357.         }

  1358.     }

  1359.     for (; k < sbr->kx[0] + sbr->m[0]; k++) {

  1360.         for (i = 0; i < i_Temp; i++) {

  1361.             X[0][i][k] = Y0[i + i_f][k][0];

  1362.             X[1][i][k] = Y0[i + i_f][k][1];

  1363.         }

  1364.     }

  1365. 

  1366.     for (k = 0; k < sbr->kx[1]; k++) {

  1367.         for (i = i_Temp; i < 38; i++) {

  1368.             X[0][i][k] = X_low[k][i + ENVELOPE_ADJUSTMENT_OFFSET][0];

  1369.             X[1][i][k] = X_low[k][i + ENVELOPE_ADJUSTMENT_OFFSET][1];

  1370.         }

  1371.     }

  1372.     for (; k < sbr->kx[1] + sbr->m[1]; k++) {

  1373.         for (i = i_Temp; i < i_f; i++) {

  1374.             X[0][i][k] = Y1[i][k][0];

  1375.             X[1][i][k] = Y1[i][k][1];

  1376.         }

  1377.     }

  1378.     return 0;

  1379. }

  1380. 

  1381. /** High Frequency Adjustment (14496-3 sp04 p217) and Mapping

  1382.  * (14496-3 sp04 p217)

  1383.  */

  1384. static void sbr_mapping(AACContext *ac, SpectralBandReplication *sbr,

  1385.                         SBRData *ch_data, int e_a[2])

  1386. {

  1387.     int e, i, m;

  1388. 

  1389.     memset(ch_data->s_indexmapped[1], 0, 7*sizeof(ch_data->s_indexmapped[1]));

  1390.     for (e = 0; e < ch_data->bs_num_env; e++) {

  1391.         const unsigned int ilim = sbr->n[ch_data->bs_freq_res[e + 1]];

  1392.         uint16_t *table = ch_data->bs_freq_res[e + 1] ? sbr->f_tablehigh : sbr->f_tablelow;

  1393.         int k;

  1394. 

  1395.         for (i = 0; i < ilim; i++)

  1396.             for (m = table[i]; m < table[i + 1]; m++)

  1397.                 sbr->e_origmapped[e][m - sbr->kx[1]] = ch_data->env_facs[e+1][i];

  1398. 

  1399.         // ch_data->bs_num_noise > 1 => 2 noise floors

  1400.         k = (ch_data->bs_num_noise > 1) && (ch_data->t_env[e] >= ch_data->t_q[1]);

  1401.         for (i = 0; i < sbr->n_q; i++)

  1402.             for (m = sbr->f_tablenoise[i]; m < sbr->f_tablenoise[i + 1]; m++)

  1403.                 sbr->q_mapped[e][m - sbr->kx[1]] = ch_data->noise_facs[k+1][i];

  1404. 

  1405.         for (i = 0; i < sbr->n[1]; i++) {

  1406.             if (ch_data->bs_add_harmonic_flag) {

  1407.                 const unsigned int m_midpoint =

  1408.                     (sbr->f_tablehigh[i] + sbr->f_tablehigh[i + 1]) >> 1;

  1409. 

  1410.                 ch_data->s_indexmapped[e + 1][m_midpoint - sbr->kx[1]] = ch_data->bs_add_harmonic[i] *

  1411.                     (e >= e_a[1] || (ch_data->s_indexmapped[0][m_midpoint - sbr->kx[1]] == 1));

  1412.             }

  1413.         }

  1414. 

  1415.         for (i = 0; i < ilim; i++) {

  1416.             int additional_sinusoid_present = 0;

  1417.             for (m = table[i]; m < table[i + 1]; m++) {

  1418.                 if (ch_data->s_indexmapped[e + 1][m - sbr->kx[1]]) {

  1419.                     additional_sinusoid_present = 1;

  1420.                     break;

  1421.                 }

  1422.             }

  1423.             memset(&sbr->s_mapped[e][table[i] - sbr->kx[1]], additional_sinusoid_present,

  1424.                    (table[i + 1] - table[i]) * sizeof(sbr->s_mapped[e][0]));

  1425.         }

  1426.     }

  1427. 

  1428.     memcpy(ch_data->s_indexmapped[0], ch_data->s_indexmapped[ch_data->bs_num_env], sizeof(ch_data->s_indexmapped[0]));

  1429. }

  1430. 

  1431. /// Estimation of current envelope (14496-3 sp04 p218)

  1432. static void sbr_env_estimate(float (*e_curr)[48], float X_high[64][40][2],

  1433.                              SpectralBandReplication *sbr, SBRData *ch_data)

  1434. {

  1435.     int e, m;

  1436.     int kx1 = sbr->kx[1];

  1437. 

  1438.     if (sbr->bs_interpol_freq) {

  1439.         for (e = 0; e < ch_data->bs_num_env; e++) {

  1440.             const float recip_env_size = 0.5f / (ch_data->t_env[e + 1] - ch_data->t_env[e]);

  1441.             int ilb = ch_data->t_env[e]     * 2 + ENVELOPE_ADJUSTMENT_OFFSET;

  1442.             int iub = ch_data->t_env[e + 1] * 2 + ENVELOPE_ADJUSTMENT_OFFSET;

  1443. 

  1444.             for (m = 0; m < sbr->m[1]; m++) {

  1445.                 float sum = sbr->dsp.sum_square(X_high[m+kx1] + ilb, iub - ilb);

  1446.                 e_curr[e][m] = sum * recip_env_size;

  1447.             }

  1448.         }

  1449.     } else {

  1450.         int k, p;

  1451. 

  1452.         for (e = 0; e < ch_data->bs_num_env; e++) {

  1453.             const int env_size = 2 * (ch_data->t_env[e + 1] - ch_data->t_env[e]);

  1454.             int ilb = ch_data->t_env[e]     * 2 + ENVELOPE_ADJUSTMENT_OFFSET;

  1455.             int iub = ch_data->t_env[e + 1] * 2 + ENVELOPE_ADJUSTMENT_OFFSET;

  1456.             const uint16_t *table = ch_data->bs_freq_res[e + 1] ? sbr->f_tablehigh : sbr->f_tablelow;

  1457. 

  1458.             for (p = 0; p < sbr->n[ch_data->bs_freq_res[e + 1]]; p++) {

  1459.                 float sum = 0.0f;

  1460.                 const int den = env_size * (table[p + 1] - table[p]);

  1461. 

  1462.                 for (k = table[p]; k < table[p + 1]; k++) {

  1463.                     sum += sbr->dsp.sum_square(X_high[k] + ilb, iub - ilb);

  1464.                 }

  1465.                 sum /= den;

  1466.                 for (k = table[p]; k < table[p + 1]; k++) {

  1467.                     e_curr[e][k - kx1] = sum;

  1468.                 }

  1469.             }

  1470.         }

  1471.     }

  1472. }

  1473. 

  1474. /**

  1475.  * Calculation of levels of additional HF signal components (14496-3 sp04 p219)

  1476.  * and Calculation of gain (14496-3 sp04 p219)

  1477.  */

  1478. static void sbr_gain_calc(AACContext *ac, SpectralBandReplication *sbr,

  1479.                           SBRData *ch_data, const int e_a[2])

  1480. {

  1481.     int e, k, m;

  1482.     // max gain limits : -3dB, 0dB, 3dB, inf dB (limiter off)

  1483.     static const float limgain[4] = { 0.70795, 1.0, 1.41254, 10000000000 };

  1484. 

  1485.     for (e = 0; e < ch_data->bs_num_env; e++) {

  1486.         int delta = !((e == e_a[1]) || (e == e_a[0]));

  1487.         for (k = 0; k < sbr->n_lim; k++) {

  1488.             float gain_boost, gain_max;

  1489.             float sum[2] = { 0.0f, 0.0f };

  1490.             for (m = sbr->f_tablelim[k] - sbr->kx[1]; m < sbr->f_tablelim[k + 1] - sbr->kx[1]; m++) {

  1491.                 const float temp = sbr->e_origmapped[e][m] / (1.0f + sbr->q_mapped[e][m]);

  1492.                 sbr->q_m[e][m] = sqrtf(temp * sbr->q_mapped[e][m]);

  1493.                 sbr->s_m[e][m] = sqrtf(temp * ch_data->s_indexmapped[e + 1][m]);

  1494.                 if (!sbr->s_mapped[e][m]) {

  1495.                     sbr->gain[e][m] = sqrtf(sbr->e_origmapped[e][m] /

  1496.                                             ((1.0f + sbr->e_curr[e][m]) *

  1497.                                              (1.0f + sbr->q_mapped[e][m] * delta)));

  1498.                 } else {

  1499.                     sbr->gain[e][m] = sqrtf(sbr->e_origmapped[e][m] * sbr->q_mapped[e][m] /

  1500.                                             ((1.0f + sbr->e_curr[e][m]) *

  1501.                                              (1.0f + sbr->q_mapped[e][m])));

  1502.                 }

  1503.             }

  1504.             for (m = sbr->f_tablelim[k] - sbr->kx[1]; m < sbr->f_tablelim[k + 1] - sbr->kx[1]; m++) {

  1505.                 sum[0] += sbr->e_origmapped[e][m];

  1506.                 sum[1] += sbr->e_curr[e][m];

  1507.             }

  1508.             gain_max = limgain[sbr->bs_limiter_gains] * sqrtf((FLT_EPSILON + sum[0]) / (FLT_EPSILON + sum[1]));

  1509.             gain_max = FFMIN(100000.f, gain_max);

  1510.             for (m = sbr->f_tablelim[k] - sbr->kx[1]; m < sbr->f_tablelim[k + 1] - sbr->kx[1]; m++) {

  1511.                 float q_m_max   = sbr->q_m[e][m] * gain_max / sbr->gain[e][m];

  1512.                 sbr->q_m[e][m]  = FFMIN(sbr->q_m[e][m], q_m_max);

  1513.                 sbr->gain[e][m] = FFMIN(sbr->gain[e][m], gain_max);

  1514.             }

  1515.             sum[0] = sum[1] = 0.0f;

  1516.             for (m = sbr->f_tablelim[k] - sbr->kx[1]; m < sbr->f_tablelim[k + 1] - sbr->kx[1]; m++) {

  1517.                 sum[0] += sbr->e_origmapped[e][m];

  1518.                 sum[1] += sbr->e_curr[e][m] * sbr->gain[e][m] * sbr->gain[e][m]

  1519.                           + sbr->s_m[e][m] * sbr->s_m[e][m]

  1520.                           + (delta && !sbr->s_m[e][m]) * sbr->q_m[e][m] * sbr->q_m[e][m];

  1521.             }

  1522.             gain_boost = sqrtf((FLT_EPSILON + sum[0]) / (FLT_EPSILON + sum[1]));

  1523.             gain_boost = FFMIN(1.584893192f, gain_boost);

  1524.             for (m = sbr->f_tablelim[k] - sbr->kx[1]; m < sbr->f_tablelim[k + 1] - sbr->kx[1]; m++) {

  1525.                 sbr->gain[e][m] *= gain_boost;

  1526.                 sbr->q_m[e][m]  *= gain_boost;

  1527.                 sbr->s_m[e][m]  *= gain_boost;

  1528.             }

  1529.         }

  1530.     }

  1531. }

  1532. 

  1533. /// Assembling HF Signals (14496-3 sp04 p220)

  1534. static void sbr_hf_assemble(float Y1[38][64][2],

  1535.                             const float X_high[64][40][2],

  1536.                             SpectralBandReplication *sbr, SBRData *ch_data,

  1537.                             const int e_a[2])

  1538. {

  1539.     int e, i, j, m;

  1540.     const int h_SL = 4 * !sbr->bs_smoothing_mode;

  1541.     const int kx = sbr->kx[1];

  1542.     const int m_max = sbr->m[1];

  1543.     static const float h_smooth[5] = {

  1544.         0.33333333333333,

  1545.         0.30150283239582,

  1546.         0.21816949906249,

  1547.         0.11516383427084,

  1548.         0.03183050093751,

  1549.     };

  1550.     static const int8_t phi[2][4] = {

  1551.         {  1,  0, -1,  0}, // real

  1552.         {  0,  1,  0, -1}, // imaginary

  1553.     };

  1554.     float (*g_temp)[48] = ch_data->g_temp, (*q_temp)[48] = ch_data->q_temp;

  1555.     int indexnoise = ch_data->f_indexnoise;

  1556.     int indexsine  = ch_data->f_indexsine;

  1557. 

  1558.     if (sbr->reset) {

  1559.         for (i = 0; i < h_SL; i++) {

  1560.             memcpy(g_temp[i + 2*ch_data->t_env[0]], sbr->gain[0], m_max * sizeof(sbr->gain[0][0]));

  1561.             memcpy(q_temp[i + 2*ch_data->t_env[0]], sbr->q_m[0],  m_max * sizeof(sbr->q_m[0][0]));

  1562.         }

  1563.     } else if (h_SL) {

  1564.         memcpy(g_temp[2*ch_data->t_env[0]], g_temp[2*ch_data->t_env_num_env_old], 4*sizeof(g_temp[0]));

  1565.         memcpy(q_temp[2*ch_data->t_env[0]], q_temp[2*ch_data->t_env_num_env_old], 4*sizeof(q_temp[0]));

  1566.     }

  1567. 

  1568.     for (e = 0; e < ch_data->bs_num_env; e++) {

  1569.         for (i = 2 * ch_data->t_env[e]; i < 2 * ch_data->t_env[e + 1]; i++) {

  1570.             memcpy(g_temp[h_SL + i], sbr->gain[e], m_max * sizeof(sbr->gain[0][0]));

  1571.             memcpy(q_temp[h_SL + i], sbr->q_m[e],  m_max * sizeof(sbr->q_m[0][0]));

  1572.         }

  1573.     }

  1574. 

  1575.     for (e = 0; e < ch_data->bs_num_env; e++) {

  1576.         for (i = 2 * ch_data->t_env[e]; i < 2 * ch_data->t_env[e + 1]; i++) {

  1577.             int phi_sign = (1 - 2*(kx & 1));

  1578.             LOCAL_ALIGNED_16(float, g_filt_tab, [48]);

  1579.             LOCAL_ALIGNED_16(float, q_filt_tab, [48]);

  1580.             float *g_filt, *q_filt;

  1581. 

  1582.             if (h_SL && e != e_a[0] && e != e_a[1]) {

  1583.                 g_filt = g_filt_tab;

  1584.                 q_filt = q_filt_tab;

  1585.                 for (m = 0; m < m_max; m++) {

  1586.                     const int idx1 = i + h_SL;

  1587.                     g_filt[m] = 0.0f;

  1588.                     q_filt[m] = 0.0f;

  1589.                     for (j = 0; j <= h_SL; j++) {

  1590.                         g_filt[m] += g_temp[idx1 - j][m] * h_smooth[j];

  1591.                         q_filt[m] += q_temp[idx1 - j][m] * h_smooth[j];

  1592.                     }

  1593.                 }

  1594.             } else {

  1595.                 g_filt = g_temp[i + h_SL];

  1596.                 q_filt = q_temp[i];

  1597.             }

  1598. 

  1599.             sbr->dsp.hf_g_filt(Y1[i] + kx, X_high + kx, g_filt, m_max,

  1600.                                i + ENVELOPE_ADJUSTMENT_OFFSET);

  1601. 

  1602.             if (e != e_a[0] && e != e_a[1]) {

  1603.                 sbr->dsp.hf_apply_noise[indexsine](Y1[i] + kx, sbr->s_m[e],

  1604.                                                    q_filt, indexnoise,

  1605.                                                    kx, m_max);

  1606.             } else {

  1607.                 for (m = 0; m < m_max; m++) {

  1608.                     Y1[i][m + kx][0] +=

  1609.                         sbr->s_m[e][m] * phi[0][indexsine];

  1610.                     Y1[i][m + kx][1] +=

  1611.                         sbr->s_m[e][m] * (phi[1][indexsine] * phi_sign);

  1612.                     phi_sign = -phi_sign;

  1613.                 }

  1614.             }

  1615.             indexnoise = (indexnoise + m_max) & 0x1ff;

  1616.             indexsine = (indexsine + 1) & 3;

  1617.         }

  1618.     }

  1619.     ch_data->f_indexnoise = indexnoise;

  1620.     ch_data->f_indexsine  = indexsine;

  1621. }

  1622. 

  1623. void ff_sbr_apply(AACContext *ac, SpectralBandReplication *sbr, int id_aac,

  1624.                   float* L, float* R)

  1625. {

  1626.     int downsampled = ac->m4ac.ext_sample_rate < sbr->sample_rate;

  1627.     int ch;

  1628.     int nch = (id_aac == TYPE_CPE) ? 2 : 1;

  1629. 

  1630.     if (sbr->start) {

  1631.         sbr_dequant(sbr, id_aac);

  1632.     }

  1633.     for (ch = 0; ch < nch; ch++) {

  1634.         /* decode channel */

  1635.         sbr_qmf_analysis(&ac->dsp, &sbr->mdct_ana, &sbr->dsp, ch ? R : L, sbr->data[ch].analysis_filterbank_samples,

  1636.                          (float*)sbr->qmf_filter_scratch,

  1637.                          sbr->data[ch].W);

  1638.         sbr_lf_gen(ac, sbr, sbr->X_low, sbr->data[ch].W);

  1639.         if (sbr->start) {

  1640.             sbr_hf_inverse_filter(&sbr->dsp, sbr->alpha0, sbr->alpha1, sbr->X_low, sbr->k[0]);

  1641.             sbr_chirp(sbr, &sbr->data[ch]);

  1642.             sbr_hf_gen(ac, sbr, sbr->X_high, sbr->X_low, sbr->alpha0, sbr->alpha1,

  1643.                        sbr->data[ch].bw_array, sbr->data[ch].t_env,

  1644.                        sbr->data[ch].bs_num_env);

  1645. 

  1646.             // hf_adj

  1647.             sbr_mapping(ac, sbr, &sbr->data[ch], sbr->data[ch].e_a);

  1648.             sbr_env_estimate(sbr->e_curr, sbr->X_high, sbr, &sbr->data[ch]);

  1649.             sbr_gain_calc(ac, sbr, &sbr->data[ch], sbr->data[ch].e_a);

  1650.             sbr->data[ch].Ypos ^= 1;

  1651.             sbr_hf_assemble(sbr->data[ch].Y[sbr->data[ch].Ypos],

  1652.                             sbr->X_high, sbr, &sbr->data[ch],

  1653.                             sbr->data[ch].e_a);

  1654.         }

  1655. 

  1656.         /* synthesis */

  1657.         sbr_x_gen(sbr, sbr->X[ch],

  1658.                   sbr->data[ch].Y[1-sbr->data[ch].Ypos],

  1659.                   sbr->data[ch].Y[  sbr->data[ch].Ypos],

  1660.                   sbr->X_low, ch);

  1661.     }

  1662. 

  1663.     if (ac->m4ac.ps == 1) {

  1664.         if (sbr->ps.start) {

  1665.             ff_ps_apply(ac->avctx, &sbr->ps, sbr->X[0], sbr->X[1], sbr->kx[1] + sbr->m[1]);

  1666.         } else {

  1667.             memcpy(sbr->X[1], sbr->X[0], sizeof(sbr->X[0]));

  1668.         }

  1669.         nch = 2;

  1670.     }

  1671. 

  1672.     sbr_qmf_synthesis(&ac->dsp, &sbr->mdct, &sbr->dsp, L, sbr->X[0], sbr->qmf_filter_scratch,

  1673.                       sbr->data[0].synthesis_filterbank_samples,

  1674.                       &sbr->data[0].synthesis_filterbank_samples_offset,

  1675.                       downsampled);

  1676.     if (nch == 2)

  1677.         sbr_qmf_synthesis(&ac->dsp, &sbr->mdct, &sbr->dsp, R, sbr->X[1], sbr->qmf_filter_scratch,

  1678.                           sbr->data[1].synthesis_filterbank_samples,

  1679.                           &sbr->data[1].synthesis_filterbank_samples_offset,

  1680.                           downsampled);

  1681. }