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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 FFmpeg.

  7.  *

  8.  * FFmpeg 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.  * FFmpeg 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 FFmpeg; 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. #include "libavutil/avassert.h"

  38. 

  39. #include <stdint.h>

  40. #include <float.h>

  41. #include <math.h>

  42. 

  43. #define ENVELOPE_ADJUSTMENT_OFFSET 2

  44. #define NOISE_FLOOR_OFFSET 6.0f

  45. 

  46. /**

  47.  * SBR VLC tables

  48.  */

  49. enum {

  50.     T_HUFFMAN_ENV_1_5DB,

  51.     F_HUFFMAN_ENV_1_5DB,

  52.     T_HUFFMAN_ENV_BAL_1_5DB,

  53.     F_HUFFMAN_ENV_BAL_1_5DB,

  54.     T_HUFFMAN_ENV_3_0DB,

  55.     F_HUFFMAN_ENV_3_0DB,

  56.     T_HUFFMAN_ENV_BAL_3_0DB,

  57.     F_HUFFMAN_ENV_BAL_3_0DB,

  58.     T_HUFFMAN_NOISE_3_0DB,

  59.     T_HUFFMAN_NOISE_BAL_3_0DB,

  60. };

  61. 

  62. /**

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

  64.  */

  65. enum {

  66.     FIXFIX,

  67.     FIXVAR,

  68.     VARFIX,

  69.     VARVAR,

  70. };

  71. 

  72. enum {

  73.     EXTENSION_ID_PS = 2,

  74. };

  75. 

  76. static VLC vlc_sbr[10];

  77. static const int8_t vlc_sbr_lav[10] =

  78.     { 60, 60, 24, 24, 31, 31, 12, 12, 31, 12 };

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

  80. 

  81. #define SBR_INIT_VLC_STATIC(num, size) \

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

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

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

  85.                     size)

  86. 

  87. #define SBR_VLC_ROW(name) \

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

  89. 

  90. av_cold void ff_aac_sbr_init(void)

  91. {

  92.     int n;

  93.     static const struct {

  94.         const void *sbr_codes, *sbr_bits;

  95.         const unsigned int table_size, elem_size;

  96.     } sbr_tmp[] = {

  97.         SBR_VLC_ROW(t_huffman_env_1_5dB),

  98.         SBR_VLC_ROW(f_huffman_env_1_5dB),

  99.         SBR_VLC_ROW(t_huffman_env_bal_1_5dB),

  100.         SBR_VLC_ROW(f_huffman_env_bal_1_5dB),

  101.         SBR_VLC_ROW(t_huffman_env_3_0dB),

  102.         SBR_VLC_ROW(f_huffman_env_3_0dB),

  103.         SBR_VLC_ROW(t_huffman_env_bal_3_0dB),

  104.         SBR_VLC_ROW(f_huffman_env_bal_3_0dB),

  105.         SBR_VLC_ROW(t_huffman_noise_3_0dB),

  106.         SBR_VLC_ROW(t_huffman_noise_bal_3_0dB),

  107.     };

  108. 

  109.     // SBR VLC table initialization

  110.     SBR_INIT_VLC_STATIC(0, 1098);

  111.     SBR_INIT_VLC_STATIC(1, 1092);

  112.     SBR_INIT_VLC_STATIC(2, 768);

  113.     SBR_INIT_VLC_STATIC(3, 1026);

  114.     SBR_INIT_VLC_STATIC(4, 1058);

  115.     SBR_INIT_VLC_STATIC(5, 1052);

  116.     SBR_INIT_VLC_STATIC(6, 544);

  117.     SBR_INIT_VLC_STATIC(7, 544);

  118.     SBR_INIT_VLC_STATIC(8, 592);

  119.     SBR_INIT_VLC_STATIC(9, 512);

  120. 

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

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

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

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

  125. 

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

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

  128. 

  129.     ff_ps_init();

  130. }

  131. 

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

  133. {

  134.     float mdct_scale;

  135.     if(sbr->mdct.mdct_bits)

  136.         return;

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

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

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

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

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

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

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

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

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

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

  147.     ff_ps_ctx_init(&sbr->ps);

  148.     ff_sbrdsp_init(&sbr->dsp);

  149. }

  150. 

  151. av_cold void ff_aac_sbr_ctx_close(SpectralBandReplication *sbr)

  152. {

  153.     ff_mdct_end(&sbr->mdct);

  154.     ff_mdct_end(&sbr->mdct_ana);

  155. }

  156. 

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

  158. {

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

  160. }

  161. 

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

  163. {

  164.     int i;

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

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

  167.             return 1;

  168.     return 0;

  169. }

  170. 

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

  172. static void sbr_make_f_tablelim(SpectralBandReplication *sbr)

  173. {

  174.     int k;

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

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

  177.                                                1.18509277094158210129f,   //2^(0.49/2)

  178.                                                1.11987160404675912501f }; //2^(0.49/3)

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

  180.         int16_t patch_borders[7];

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

  182. 

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

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

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

  186. 

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

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

  189.         if (sbr->num_patches > 1)

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

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

  192. 

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

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

  195.               qsort_comparison_function_int16);

  196. 

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

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

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

  200.                 *++out = *in++;

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

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

  203.                 in++;

  204.                 sbr->n_lim--;

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

  206.                 *out = *in++;

  207.                 sbr->n_lim--;

  208.             } else {

  209.                 *++out = *in++;

  210.             }

  211.         }

  212.     } else {

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

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

  215.         sbr->n_lim = 1;

  216.     }

  217. }

  218. 

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

  220. {

  221.     unsigned int cnt = get_bits_count(gb);

  222.     uint8_t bs_header_extra_1;

  223.     uint8_t bs_header_extra_2;

  224.     int old_bs_limiter_bands = sbr->bs_limiter_bands;

  225.     SpectrumParameters old_spectrum_params;

  226. 

  227.     sbr->start = 1;

  228. 

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

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

  231. 

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

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

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

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

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

  237. 

  238.     bs_header_extra_1 = get_bits1(gb);

  239.     bs_header_extra_2 = get_bits1(gb);

  240. 

  241.     if (bs_header_extra_1) {

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

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

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

  245.     } else {

  246.         sbr->spectrum_params.bs_freq_scale  = 2;

  247.         sbr->spectrum_params.bs_alter_scale = 1;

  248.         sbr->spectrum_params.bs_noise_bands = 2;

  249.     }

  250. 

  251.     // Check if spectrum parameters changed

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

  253.         sbr->reset = 1;

  254. 

  255.     if (bs_header_extra_2) {

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

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

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

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

  260.     } else {

  261.         sbr->bs_limiter_bands  = 2;

  262.         sbr->bs_limiter_gains  = 2;

  263.         sbr->bs_interpol_freq  = 1;

  264.         sbr->bs_smoothing_mode = 1;

  265.     }

  266. 

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

  268.         sbr_make_f_tablelim(sbr);

  269. 

  270.     return get_bits_count(gb) - cnt;

  271. }

  272. 

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

  274. {

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

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

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

  278.     return min;

  279. }

  280. 

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

  282. {

  283.     int k, previous, present;

  284.     float base, prod;

  285. 

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

  287.     prod = start;

  288.     previous = start;

  289. 

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

  291.         prod *= base;

  292.         present  = lrintf(prod);

  293.         bands[k] = present - previous;

  294.         previous = present;

  295.     }

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

  297. }

  298. 

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

  300. {

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

  302.     if (n_master <= 0) {

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

  304.         return -1;

  305.     }

  306.     if (bs_xover_band >= n_master) {

  307.         av_log(avctx, AV_LOG_ERROR,

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

  309.                bs_xover_band);

  310.         return -1;

  311.     }

  312.     return 0;

  313. }

  314. 

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

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

  317.                              SpectrumParameters *spectrum)

  318. {

  319.     unsigned int temp, max_qmf_subbands;

  320.     unsigned int start_min, stop_min;

  321.     int k;

  322.     const int8_t *sbr_offset_ptr;

  323.     int16_t stop_dk[13];

  324. 

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

  326.         temp = 3000;

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

  328.         temp = 4000;

  329.     } else

  330.         temp = 5000;

  331. 

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

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

  334. 

  335.     switch (sbr->sample_rate) {

  336.     case 16000:

  337.         sbr_offset_ptr = sbr_offset[0];

  338.         break;

  339.     case 22050:

  340.         sbr_offset_ptr = sbr_offset[1];

  341.         break;

  342.     case 24000:

  343.         sbr_offset_ptr = sbr_offset[2];

  344.         break;

  345.     case 32000:

  346.         sbr_offset_ptr = sbr_offset[3];

  347.         break;

  348.     case 44100: case 48000: case 64000:

  349.         sbr_offset_ptr = sbr_offset[4];

  350.         break;

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

  352.         sbr_offset_ptr = sbr_offset[5];

  353.         break;

  354.     default:

  355.         av_log(ac->avctx, AV_LOG_ERROR,

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

  357.         return -1;

  358.     }

  359. 

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

  361. 

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

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

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

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

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

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

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

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

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

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

  372.     } else {

  373.         av_log(ac->avctx, AV_LOG_ERROR,

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

  375.         return -1;

  376.     }

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

  378. 

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

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

  381.         max_qmf_subbands = 48;

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

  383.         max_qmf_subbands = 35;

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

  385.         max_qmf_subbands = 32;

  386. 

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

  388.         av_log(ac->avctx, AV_LOG_ERROR,

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

  390.         return -1;

  391.     }

  392. 

  393.     if (!spectrum->bs_freq_scale) {

  394.         int dk, k2diff;

  395. 

  396.         dk = spectrum->bs_alter_scale + 1;

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

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

  399.             return -1;

  400. 

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

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

  403. 

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

  405.         if (k2diff < 0) {

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

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

  408.         } else if (k2diff) {

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

  410.         }

  411. 

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

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

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

  415. 

  416.     } else {

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

  418.         int two_regions, num_bands_0;

  419.         int vdk0_max, vdk1_min;

  420.         int16_t vk0[49];

  421. 

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

  423.             two_regions = 1;

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

  425.         } else {

  426.             two_regions = 0;

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

  428.         }

  429. 

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

  431. 

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

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

  434.             return -1;

  435.         }

  436. 

  437.         vk0[0] = 0;

  438. 

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

  440. 

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

  442.         vdk0_max = vk0[num_bands_0];

  443. 

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

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

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

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

  448.                 return -1;

  449.             }

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

  451.         }

  452. 

  453.         if (two_regions) {

  454.             int16_t vk1[49];

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

  456.                                                      : 1.0f; // bs_alter_scale = {0,1}

  457.             int num_bands_1 = lrintf(half_bands * invwarp *

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

  459. 

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

  461. 

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

  463. 

  464.             if (vdk1_min < vdk0_max) {

  465.                 int change;

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

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

  468.                 vk1[1]           += change;

  469.                 vk1[num_bands_1] -= change;

  470.             }

  471. 

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

  473. 

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

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

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

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

  478.                     return -1;

  479.                 }

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

  481.             }

  482. 

  483.             sbr->n_master = num_bands_0 + num_bands_1;

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

  485.                 return -1;

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

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

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

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

  490. 

  491.         } else {

  492.             sbr->n_master = num_bands_0;

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

  494.                 return -1;

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

  496.         }

  497.     }

  498. 

  499.     return 0;

  500. }

  501. 

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

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

  504. {

  505.     int i, k, sb = 0;

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

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

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

  509. 

  510.     sbr->num_patches = 0;

  511. 

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

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

  514.     } else

  515.         k = sbr->n_master;

  516. 

  517.     do {

  518.         int odd = 0;

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

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

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

  522.         }

  523. 

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

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

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

  527.         // count of 6 patches

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

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

  530.             return -1;

  531.         }

  532. 

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

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

  535. 

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

  537.             usb = sb;

  538.             msb = sb;

  539.             sbr->num_patches++;

  540.         } else

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

  542. 

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

  544.             k = sbr->n_master;

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

  546. 

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

  548.         sbr->num_patches--;

  549. 

  550.     return 0;

  551. }

  552. 

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

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

  555. {

  556.     int k, temp;

  557. 

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

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

  560. 

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

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

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

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

  565. 

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

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

  568.         av_log(ac->avctx, AV_LOG_ERROR,

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

  570.         return -1;

  571.     }

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

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

  574.         return -1;

  575.     }

  576. 

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

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

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

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

  581. 

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

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

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

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

  586.         return -1;

  587.     }

  588. 

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

  590.     temp = 0;

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

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

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

  594.     }

  595. 

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

  597.         return -1;

  598. 

  599.     sbr_make_f_tablelim(sbr);

  600. 

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

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

  603. 

  604.     return 0;

  605. }

  606. 

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

  608.                                               int elements)

  609. {

  610.     int i;

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

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

  613.     }

  614. }

  615. 

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

  617. static const int8_t ceil_log2[] = {

  618.     0, 1, 2, 2, 3, 3,

  619. };

  620. 

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

  622.                          GetBitContext *gb, SBRData *ch_data)

  623. {

  624.     int i;

  625.     unsigned bs_pointer = 0;

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

  627.     int abs_bord_trail = 16;

  628.     int num_rel_lead, num_rel_trail;

  629.     unsigned bs_num_env_old = ch_data->bs_num_env;

  630. 

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

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

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

  634. 

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

  636.     case FIXFIX:

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

  638.         num_rel_lead                        = ch_data->bs_num_env - 1;

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

  640.             ch_data->bs_amp_res = 0;

  641. 

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

  643.             av_log(ac->avctx, AV_LOG_ERROR,

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

  645.                    ch_data->bs_num_env);

  646.             return -1;

  647.         }

  648. 

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

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

  651. 

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

  653.                    ch_data->bs_num_env;

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

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

  656. 

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

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

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

  660.         break;

  661.     case FIXVAR:

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

  663.         num_rel_trail                       = get_bits(gb, 2);

  664.         ch_data->bs_num_env                 = num_rel_trail + 1;

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

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

  667. 

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

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

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

  671. 

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

  673. 

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

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

  676.         break;

  677.     case VARFIX:

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

  679.         num_rel_lead                        = get_bits(gb, 2);

  680.         ch_data->bs_num_env                 = num_rel_lead + 1;

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

  682. 

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

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

  685. 

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

  687. 

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

  689.         break;

  690.     case VARVAR:

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

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

  693.         num_rel_lead                        = get_bits(gb, 2);

  694.         num_rel_trail                       = get_bits(gb, 2);

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

  696. 

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

  698.             av_log(ac->avctx, AV_LOG_ERROR,

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

  700.                    ch_data->bs_num_env);

  701.             return -1;

  702.         }

  703. 

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

  705. 

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

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

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

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

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

  711. 

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

  713. 

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

  715.         break;

  716.     }

  717. 

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

  719.         av_log(ac->avctx, AV_LOG_ERROR,

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

  721.                bs_pointer);

  722.         return -1;

  723.     }

  724. 

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

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

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

  728.             return -1;

  729.         }

  730.     }

  731. 

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

  733. 

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

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

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

  737.         unsigned int idx;

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

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

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

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

  742.         } else { // VARFIX

  743.             if (!bs_pointer)

  744.                 idx = 1;

  745.             else if (bs_pointer == 1)

  746.                 idx = ch_data->bs_num_env - 1;

  747.             else // bs_pointer > 1

  748.                 idx = bs_pointer - 1;

  749.         }

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

  751.     }

  752. 

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

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

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

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

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

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

  759. 

  760.     return 0;

  761. }

  762. 

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

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

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

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

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

  768. 

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

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

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

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

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

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

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

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

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

  778. }

  779. 

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

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

  782.                           SBRData *ch_data)

  783. {

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

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

  786. }

  787. 

  788. /// Read inverse filtering data

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

  790.                           SBRData *ch_data)

  791. {

  792.     int i;

  793. 

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

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

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

  797. }

  798. 

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

  800.                               SBRData *ch_data, int ch)

  801. {

  802.     int bits;

  803.     int i, j, k;

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

  805.     int t_lav, f_lav;

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

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

  808. 

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

  810.         if (ch_data->bs_amp_res) {

  811.             bits   = 5;

  812.             t_huff = vlc_sbr[T_HUFFMAN_ENV_BAL_3_0DB].table;

  813.             t_lav  = vlc_sbr_lav[T_HUFFMAN_ENV_BAL_3_0DB];

  814.             f_huff = vlc_sbr[F_HUFFMAN_ENV_BAL_3_0DB].table;

  815.             f_lav  = vlc_sbr_lav[F_HUFFMAN_ENV_BAL_3_0DB];

  816.         } else {

  817.             bits   = 6;

  818.             t_huff = vlc_sbr[T_HUFFMAN_ENV_BAL_1_5DB].table;

  819.             t_lav  = vlc_sbr_lav[T_HUFFMAN_ENV_BAL_1_5DB];

  820.             f_huff = vlc_sbr[F_HUFFMAN_ENV_BAL_1_5DB].table;

  821.             f_lav  = vlc_sbr_lav[F_HUFFMAN_ENV_BAL_1_5DB];

  822.         }

  823.     } else {

  824.         if (ch_data->bs_amp_res) {

  825.             bits   = 6;

  826.             t_huff = vlc_sbr[T_HUFFMAN_ENV_3_0DB].table;

  827.             t_lav  = vlc_sbr_lav[T_HUFFMAN_ENV_3_0DB];

  828.             f_huff = vlc_sbr[F_HUFFMAN_ENV_3_0DB].table;

  829.             f_lav  = vlc_sbr_lav[F_HUFFMAN_ENV_3_0DB];

  830.         } else {

  831.             bits   = 7;

  832.             t_huff = vlc_sbr[T_HUFFMAN_ENV_1_5DB].table;

  833.             t_lav  = vlc_sbr_lav[T_HUFFMAN_ENV_1_5DB];

  834.             f_huff = vlc_sbr[F_HUFFMAN_ENV_1_5DB].table;

  835.             f_lav  = vlc_sbr_lav[F_HUFFMAN_ENV_1_5DB];

  836.         }

  837.     }

  838. 

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

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

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

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

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

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

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

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

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

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

  849.                 }

  850.             } else {

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

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

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

  854.                 }

  855.             }

  856.         } else {

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

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

  859.                 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);

  860.         }

  861.     }

  862. 

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

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

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

  866. }

  867. 

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

  869.                            SBRData *ch_data, int ch)

  870. {

  871.     int i, j;

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

  873.     int t_lav, f_lav;

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

  875. 

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

  877.         t_huff = vlc_sbr[T_HUFFMAN_NOISE_BAL_3_0DB].table;

  878.         t_lav  = vlc_sbr_lav[T_HUFFMAN_NOISE_BAL_3_0DB];

  879.         f_huff = vlc_sbr[F_HUFFMAN_ENV_BAL_3_0DB].table;

  880.         f_lav  = vlc_sbr_lav[F_HUFFMAN_ENV_BAL_3_0DB];

  881.     } else {

  882.         t_huff = vlc_sbr[T_HUFFMAN_NOISE_3_0DB].table;

  883.         t_lav  = vlc_sbr_lav[T_HUFFMAN_NOISE_3_0DB];

  884.         f_huff = vlc_sbr[F_HUFFMAN_ENV_3_0DB].table;

  885.         f_lav  = vlc_sbr_lav[F_HUFFMAN_ENV_3_0DB];

  886.     }

  887. 

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

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

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

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

  892.         } else {

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

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

  895.                 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);

  896.         }

  897.     }

  898. 

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

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

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

  902. }

  903. 

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

  905.                                GetBitContext *gb,

  906.                                int bs_extension_id, int *num_bits_left)

  907. {

  908.     switch (bs_extension_id) {

  909.     case EXTENSION_ID_PS:

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

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

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

  913.             *num_bits_left = 0;

  914.         } else {

  915. #if 1

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

  917. #else

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

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

  920.             *num_bits_left = 0;

  921. #endif

  922.         }

  923.         break;

  924.     default:

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

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

  927.         *num_bits_left = 0;

  928.         break;

  929.     }

  930. }

  931. 

  932. static int read_sbr_single_channel_element(AACContext *ac,

  933.                                             SpectralBandReplication *sbr,

  934.                                             GetBitContext *gb)

  935. {

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

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

  938. 

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

  940.         return -1;

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

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

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

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

  945. 

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

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

  948. 

  949.     return 0;

  950. }

  951. 

  952. static int read_sbr_channel_pair_element(AACContext *ac,

  953.                                           SpectralBandReplication *sbr,

  954.                                           GetBitContext *gb)

  955. {

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

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

  958. 

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

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

  961.             return -1;

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

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

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

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

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

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

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

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

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

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

  972.     } else {

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

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

  975.             return -1;

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

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

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

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

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

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

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

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

  984.     }

  985. 

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

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

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

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

  990. 

  991.     return 0;

  992. }

  993. 

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

  995.                                   GetBitContext *gb, int id_aac)

  996. {

  997.     unsigned int cnt = get_bits_count(gb);

  998. 

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

  1000.         if (read_sbr_single_channel_element(ac, sbr, gb)) {

  1001.             sbr->start = 0;

  1002.             return get_bits_count(gb) - cnt;

  1003.         }

  1004.     } else if (id_aac == TYPE_CPE) {

  1005.         if (read_sbr_channel_pair_element(ac, sbr, gb)) {

  1006.             sbr->start = 0;

  1007.             return get_bits_count(gb) - cnt;

  1008.         }

  1009.     } else {

  1010.         av_log(ac->avctx, AV_LOG_ERROR,

  1011.             "Invalid bitstream - cannot apply SBR to element type %d\n", id_aac);

  1012.         sbr->start = 0;

  1013.         return get_bits_count(gb) - cnt;

  1014.     }

  1015.     if (get_bits1(gb)) { // bs_extended_data

  1016.         int num_bits_left = get_bits(gb, 4); // bs_extension_size

  1017.         if (num_bits_left == 15)

  1018.             num_bits_left += get_bits(gb, 8); // bs_esc_count

  1019. 

  1020.         num_bits_left <<= 3;

  1021.         while (num_bits_left > 7) {

  1022.             num_bits_left -= 2;

  1023.             read_sbr_extension(ac, sbr, gb, get_bits(gb, 2), &num_bits_left); // bs_extension_id

  1024.         }

  1025.         if (num_bits_left < 0) {

  1026.             av_log(ac->avctx, AV_LOG_ERROR, "SBR Extension over read.\n");

  1027.         }

  1028.         if (num_bits_left > 0)

  1029.             skip_bits(gb, num_bits_left);

  1030.     }

  1031. 

  1032.     return get_bits_count(gb) - cnt;

  1033. }

  1034. 

  1035. static void sbr_reset(AACContext *ac, SpectralBandReplication *sbr)

  1036. {

  1037.     int err;

  1038.     err = sbr_make_f_master(ac, sbr, &sbr->spectrum_params);

  1039.     if (err >= 0)

  1040.         err = sbr_make_f_derived(ac, sbr);

  1041.     if (err < 0) {

  1042.         av_log(ac->avctx, AV_LOG_ERROR,

  1043.                "SBR reset failed. Switching SBR to pure upsampling mode.\n");

  1044.         sbr->start = 0;

  1045.     }

  1046. }

  1047. 

  1048. /**

  1049.  * Decode Spectral Band Replication extension data; reference: table 4.55.

  1050.  *

  1051.  * @param   crc flag indicating the presence of CRC checksum

  1052.  * @param   cnt length of TYPE_FIL syntactic element in bytes

  1053.  *

  1054.  * @return  Returns number of bytes consumed from the TYPE_FIL element.

  1055.  */

  1056. int ff_decode_sbr_extension(AACContext *ac, SpectralBandReplication *sbr,

  1057.                             GetBitContext *gb_host, int crc, int cnt, int id_aac)

  1058. {

  1059.     unsigned int num_sbr_bits = 0, num_align_bits;

  1060.     unsigned bytes_read;

  1061.     GetBitContext gbc = *gb_host, *gb = &gbc;

  1062.     skip_bits_long(gb_host, cnt*8 - 4);

  1063. 

  1064.     sbr->reset = 0;

  1065. 

  1066.     if (!sbr->sample_rate)

  1067.         sbr->sample_rate = 2 * ac->m4ac.sample_rate; //TODO use the nominal sample rate for arbitrary sample rate support

  1068.     if (!ac->m4ac.ext_sample_rate)

  1069.         ac->m4ac.ext_sample_rate = 2 * ac->m4ac.sample_rate;

  1070. 

  1071.     if (crc) {

  1072.         skip_bits(gb, 10); // bs_sbr_crc_bits; TODO - implement CRC check

  1073.         num_sbr_bits += 10;

  1074.     }

  1075. 

  1076.     //Save some state from the previous frame.

  1077.     sbr->kx[0] = sbr->kx[1];

  1078.     sbr->m[0] = sbr->m[1];

  1079. 

  1080.     num_sbr_bits++;

  1081.     if (get_bits1(gb)) // bs_header_flag

  1082.         num_sbr_bits += read_sbr_header(sbr, gb);

  1083. 

  1084.     if (sbr->reset)

  1085.         sbr_reset(ac, sbr);

  1086. 

  1087.     if (sbr->start)

  1088.         num_sbr_bits  += read_sbr_data(ac, sbr, gb, id_aac);

  1089. 

  1090.     num_align_bits = ((cnt << 3) - 4 - num_sbr_bits) & 7;

  1091.     bytes_read = ((num_sbr_bits + num_align_bits + 4) >> 3);

  1092. 

  1093.     if (bytes_read > cnt) {

  1094.         av_log(ac->avctx, AV_LOG_ERROR,

  1095.                "Expected to read %d SBR bytes actually read %d.\n", cnt, bytes_read);

  1096.     }

  1097.     return cnt;

  1098. }

  1099. 

  1100. /// Dequantization and stereo decoding (14496-3 sp04 p203)

  1101. static void sbr_dequant(SpectralBandReplication *sbr, int id_aac)

  1102. {

  1103.     int k, e;

  1104.     int ch;

  1105. 

  1106.     if (id_aac == TYPE_CPE && sbr->bs_coupling) {

  1107.         float alpha      = sbr->data[0].bs_amp_res ?  1.0f :  0.5f;

  1108.         float pan_offset = sbr->data[0].bs_amp_res ? 12.0f : 24.0f;

  1109.         for (e = 1; e <= sbr->data[0].bs_num_env; e++) {

  1110.             for (k = 0; k < sbr->n[sbr->data[0].bs_freq_res[e]]; k++) {

  1111.                 float temp1 = exp2f(sbr->data[0].env_facs[e][k] * alpha + 7.0f);

  1112.                 float temp2 = exp2f((pan_offset - sbr->data[1].env_facs[e][k]) * alpha);

  1113.                 float fac   = temp1 / (1.0f + temp2);

  1114.                 sbr->data[0].env_facs[e][k] = fac;

  1115.                 sbr->data[1].env_facs[e][k] = fac * temp2;

  1116.             }

  1117.         }

  1118.         for (e = 1; e <= sbr->data[0].bs_num_noise; e++) {

  1119.             for (k = 0; k < sbr->n_q; k++) {

  1120.                 float temp1 = exp2f(NOISE_FLOOR_OFFSET - sbr->data[0].noise_facs[e][k] + 1);

  1121.                 float temp2 = exp2f(12 - sbr->data[1].noise_facs[e][k]);

  1122.                 float fac   = temp1 / (1.0f + temp2);

  1123.                 sbr->data[0].noise_facs[e][k] = fac;

  1124.                 sbr->data[1].noise_facs[e][k] = fac * temp2;

  1125.             }

  1126.         }

  1127.     } else { // SCE or one non-coupled CPE

  1128.         for (ch = 0; ch < (id_aac == TYPE_CPE) + 1; ch++) {

  1129.             float alpha = sbr->data[ch].bs_amp_res ? 1.0f : 0.5f;

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

  1131.                 for (k = 0; k < sbr->n[sbr->data[ch].bs_freq_res[e]]; k++)

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

  1133.                         exp2f(alpha * sbr->data[ch].env_facs[e][k] + 6.0f);

  1134.             for (e = 1; e <= sbr->data[ch].bs_num_noise; e++)

  1135.                 for (k = 0; k < sbr->n_q; k++)

  1136.                     sbr->data[ch].noise_facs[e][k] =

  1137.                         exp2f(NOISE_FLOOR_OFFSET - sbr->data[ch].noise_facs[e][k]);

  1138.         }

  1139.     }

  1140. }

  1141. 

  1142. /**

  1143.  * Analysis QMF Bank (14496-3 sp04 p206)

  1144.  *

  1145.  * @param   x       pointer to the beginning of the first sample window

  1146.  * @param   W       array of complex-valued samples split into subbands

  1147.  */

  1148. static void sbr_qmf_analysis(DSPContext *dsp, FFTContext *mdct,

  1149.                              SBRDSPContext *sbrdsp, const float *in, float *x,

  1150.                              float z[320], float W[2][32][32][2])

  1151. {

  1152.     int i;

  1153.     memcpy(W[0], W[1], sizeof(W[0]));

  1154.     memcpy(x    , x+1024, (320-32)*sizeof(x[0]));

  1155.     memcpy(x+288, in,         1024*sizeof(x[0]));

  1156.     for (i = 0; i < 32; i++) { // numTimeSlots*RATE = 16*2 as 960 sample frames

  1157.                                // are not supported

  1158.         dsp->vector_fmul_reverse(z, sbr_qmf_window_ds, x, 320);

  1159.         sbrdsp->sum64x5(z);

  1160.         sbrdsp->qmf_pre_shuffle(z);

  1161.         mdct->imdct_half(mdct, z, z+64);

  1162.         sbrdsp->qmf_post_shuffle(W[1][i], z);

  1163.         x += 32;

  1164.     }

  1165. }

  1166. 

  1167. /**

  1168.  * Synthesis QMF Bank (14496-3 sp04 p206) and Downsampled Synthesis QMF Bank

  1169.  * (14496-3 sp04 p206)

  1170.  */

  1171. static void sbr_qmf_synthesis(DSPContext *dsp, FFTContext *mdct,

  1172.                               SBRDSPContext *sbrdsp,

  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.     const int step = 128 >> div;

  1180.     float *v;

  1181.     for (i = 0; i < 32; i++) {

  1182.         if (*v_off < step) {

  1183.             int saved_samples = (1280 - 128) >> div;

  1184.             memcpy(&v0[SBR_SYNTHESIS_BUF_SIZE - saved_samples], v0, saved_samples * sizeof(float));

  1185.             *v_off = SBR_SYNTHESIS_BUF_SIZE - saved_samples - step;

  1186.         } else {

  1187.             *v_off -= step;

  1188.         }

  1189.         v = v0 + *v_off;

  1190.         if (div) {

  1191.             for (n = 0; n < 32; n++) {

  1192.                 X[0][i][   n] = -X[0][i][n];

  1193.                 X[0][i][32+n] =  X[1][i][31-n];

  1194.             }

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

  1196.             sbrdsp->qmf_deint_neg(v, mdct_buf[0]);

  1197.         } else {

  1198.             sbrdsp->neg_odd_64(X[1][i]);

  1199.             mdct->imdct_half(mdct, mdct_buf[0], X[0][i]);

  1200.             mdct->imdct_half(mdct, mdct_buf[1], X[1][i]);

  1201.             sbrdsp->qmf_deint_bfly(v, mdct_buf[1], mdct_buf[0]);

  1202.         }

  1203.         dsp->vector_fmul_add(out, v                , sbr_qmf_window               , zero64, 64 >> div);

  1204.         dsp->vector_fmul_add(out, v + ( 192 >> div), sbr_qmf_window + ( 64 >> div), out   , 64 >> div);

  1205.         dsp->vector_fmul_add(out, v + ( 256 >> div), sbr_qmf_window + (128 >> div), out   , 64 >> div);

  1206.         dsp->vector_fmul_add(out, v + ( 448 >> div), sbr_qmf_window + (192 >> div), out   , 64 >> div);

  1207.         dsp->vector_fmul_add(out, v + ( 512 >> div), sbr_qmf_window + (256 >> div), out   , 64 >> div);

  1208.         dsp->vector_fmul_add(out, v + ( 704 >> div), sbr_qmf_window + (320 >> div), out   , 64 >> div);

  1209.         dsp->vector_fmul_add(out, v + ( 768 >> div), sbr_qmf_window + (384 >> div), out   , 64 >> div);

  1210.         dsp->vector_fmul_add(out, v + ( 960 >> div), sbr_qmf_window + (448 >> div), out   , 64 >> div);

  1211.         dsp->vector_fmul_add(out, v + (1024 >> div), sbr_qmf_window + (512 >> div), out   , 64 >> div);

  1212.         dsp->vector_fmul_add(out, v + (1216 >> div), sbr_qmf_window + (576 >> div), out   , 64 >> div);

  1213.         out += 64 >> div;

  1214.     }

  1215. }

  1216. 

  1217. /** High Frequency Generation (14496-3 sp04 p214+) and Inverse Filtering

  1218.  * (14496-3 sp04 p214)

  1219.  * Warning: This routine does not seem numerically stable.

  1220.  */

  1221. static void sbr_hf_inverse_filter(SBRDSPContext *dsp,

  1222.                                   float (*alpha0)[2], float (*alpha1)[2],

  1223.                                   const float X_low[32][40][2], int k0)

  1224. {

  1225.     int k;

  1226.     for (k = 0; k < k0; k++) {

  1227.         LOCAL_ALIGNED_16(float, phi, [3], [2][2]);

  1228.         float dk;

  1229. 

  1230.         dsp->autocorrelate(X_low[k], phi);

  1231. 

  1232.         dk =  phi[2][1][0] * phi[1][0][0] -

  1233.              (phi[1][1][0] * phi[1][1][0] + phi[1][1][1] * phi[1][1][1]) / 1.000001f;

  1234. 

  1235.         if (!dk) {

  1236.             alpha1[k][0] = 0;

  1237.             alpha1[k][1] = 0;

  1238.         } else {

  1239.             float temp_real, temp_im;

  1240.             temp_real = phi[0][0][0] * phi[1][1][0] -

  1241.                         phi[0][0][1] * phi[1][1][1] -

  1242.                         phi[0][1][0] * phi[1][0][0];

  1243.             temp_im   = phi[0][0][0] * phi[1][1][1] +

  1244.                         phi[0][0][1] * phi[1][1][0] -

  1245.                         phi[0][1][1] * phi[1][0][0];

  1246. 

  1247.             alpha1[k][0] = temp_real / dk;

  1248.             alpha1[k][1] = temp_im   / dk;

  1249.         }

  1250. 

  1251.         if (!phi[1][0][0]) {

  1252.             alpha0[k][0] = 0;

  1253.             alpha0[k][1] = 0;

  1254.         } else {

  1255.             float temp_real, temp_im;

  1256.             temp_real = phi[0][0][0] + alpha1[k][0] * phi[1][1][0] +

  1257.                                        alpha1[k][1] * phi[1][1][1];

  1258.             temp_im   = phi[0][0][1] + alpha1[k][1] * phi[1][1][0] -

  1259.                                        alpha1[k][0] * phi[1][1][1];

  1260. 

  1261.             alpha0[k][0] = -temp_real / phi[1][0][0];

  1262.             alpha0[k][1] = -temp_im   / phi[1][0][0];

  1263.         }

  1264. 

  1265.         if (alpha1[k][0] * alpha1[k][0] + alpha1[k][1] * alpha1[k][1] >= 16.0f ||

  1266.            alpha0[k][0] * alpha0[k][0] + alpha0[k][1] * alpha0[k][1] >= 16.0f) {

  1267.             alpha1[k][0] = 0;

  1268.             alpha1[k][1] = 0;

  1269.             alpha0[k][0] = 0;

  1270.             alpha0[k][1] = 0;

  1271.         }

  1272.     }

  1273. }

  1274. 

  1275. /// Chirp Factors (14496-3 sp04 p214)

  1276. static void sbr_chirp(SpectralBandReplication *sbr, SBRData *ch_data)

  1277. {

  1278.     int i;

  1279.     float new_bw;

  1280.     static const float bw_tab[] = { 0.0f, 0.75f, 0.9f, 0.98f };

  1281. 

  1282.     for (i = 0; i < sbr->n_q; i++) {

  1283.         if (ch_data->bs_invf_mode[0][i] + ch_data->bs_invf_mode[1][i] == 1) {

  1284.             new_bw = 0.6f;

  1285.         } else

  1286.             new_bw = bw_tab[ch_data->bs_invf_mode[0][i]];

  1287. 

  1288.         if (new_bw < ch_data->bw_array[i]) {

  1289.             new_bw = 0.75f    * new_bw + 0.25f    * ch_data->bw_array[i];

  1290.         } else

  1291.             new_bw = 0.90625f * new_bw + 0.09375f * ch_data->bw_array[i];

  1292.         ch_data->bw_array[i] = new_bw < 0.015625f ? 0.0f : new_bw;

  1293.     }

  1294. }

  1295. 

  1296. /// Generate the subband filtered lowband

  1297. static int sbr_lf_gen(AACContext *ac, SpectralBandReplication *sbr,

  1298.                       float X_low[32][40][2], const float W[2][32][32][2])

  1299. {

  1300.     int i, k;

  1301.     const int t_HFGen = 8;

  1302.     const int i_f = 32;

  1303.     memset(X_low, 0, 32*sizeof(*X_low));

  1304.     for (k = 0; k < sbr->kx[1]; k++) {

  1305.         for (i = t_HFGen; i < i_f + t_HFGen; i++) {

  1306.             X_low[k][i][0] = W[1][i - t_HFGen][k][0];

  1307.             X_low[k][i][1] = W[1][i - t_HFGen][k][1];

  1308.         }

  1309.     }

  1310.     for (k = 0; k < sbr->kx[0]; k++) {

  1311.         for (i = 0; i < t_HFGen; i++) {

  1312.             X_low[k][i][0] = W[0][i + i_f - t_HFGen][k][0];

  1313.             X_low[k][i][1] = W[0][i + i_f - t_HFGen][k][1];

  1314.         }

  1315.     }

  1316.     return 0;

  1317. }

  1318. 

  1319. /// High Frequency Generator (14496-3 sp04 p215)

  1320. static int sbr_hf_gen(AACContext *ac, SpectralBandReplication *sbr,

  1321.                       float X_high[64][40][2], const float X_low[32][40][2],

  1322.                       const float (*alpha0)[2], const float (*alpha1)[2],

  1323.                       const float bw_array[5], const uint8_t *t_env,

  1324.                       int bs_num_env)

  1325. {

  1326.     int j, x;

  1327.     int g = 0;

  1328.     int k = sbr->kx[1];

  1329.     for (j = 0; j < sbr->num_patches; j++) {

  1330.         for (x = 0; x < sbr->patch_num_subbands[j]; x++, k++) {

  1331.             const int p = sbr->patch_start_subband[j] + x;

  1332.             while (g <= sbr->n_q && k >= sbr->f_tablenoise[g])

  1333.                 g++;

  1334.             g--;

  1335. 

  1336.             if (g < 0) {

  1337.                 av_log(ac->avctx, AV_LOG_ERROR,

  1338.                        "ERROR : no subband found for frequency %d\n", k);

  1339.                 return -1;

  1340.             }

  1341. 

  1342.             sbr->dsp.hf_gen(X_high[k] + ENVELOPE_ADJUSTMENT_OFFSET,

  1343.                             X_low[p]  + ENVELOPE_ADJUSTMENT_OFFSET,

  1344.                             alpha0[p], alpha1[p], bw_array[g],

  1345.                             2 * t_env[0], 2 * t_env[bs_num_env]);

  1346.         }

  1347.     }

  1348.     if (k < sbr->m[1] + sbr->kx[1])

  1349.         memset(X_high + k, 0, (sbr->m[1] + sbr->kx[1] - k) * sizeof(*X_high));

  1350. 

  1351.     return 0;

  1352. }

  1353. 

  1354. /// Generate the subband filtered lowband

  1355. static int sbr_x_gen(SpectralBandReplication *sbr, float X[2][38][64],

  1356.                      const float Y0[38][64][2], const float Y1[38][64][2],

  1357.                      const float X_low[32][40][2], int ch)

  1358. {

  1359.     int k, i;

  1360.     const int i_f = 32;

  1361.     const int i_Temp = FFMAX(2*sbr->data[ch].t_env_num_env_old - i_f, 0);

  1362.     memset(X, 0, 2*sizeof(*X));

  1363.     for (k = 0; k < sbr->kx[0]; k++) {

  1364.         for (i = 0; i < i_Temp; i++) {

  1365.             X[0][i][k] = X_low[k][i + ENVELOPE_ADJUSTMENT_OFFSET][0];

  1366.             X[1][i][k] = X_low[k][i + ENVELOPE_ADJUSTMENT_OFFSET][1];

  1367.         }

  1368.     }

  1369.     for (; k < sbr->kx[0] + sbr->m[0]; k++) {

  1370.         for (i = 0; i < i_Temp; i++) {

  1371.             X[0][i][k] = Y0[i + i_f][k][0];

  1372.             X[1][i][k] = Y0[i + i_f][k][1];

  1373.         }

  1374.     }

  1375. 

  1376.     for (k = 0; k < sbr->kx[1]; k++) {

  1377.         for (i = i_Temp; i < 38; i++) {

  1378.             X[0][i][k] = X_low[k][i + ENVELOPE_ADJUSTMENT_OFFSET][0];

  1379.             X[1][i][k] = X_low[k][i + ENVELOPE_ADJUSTMENT_OFFSET][1];

  1380.         }

  1381.     }

  1382.     for (; k < sbr->kx[1] + sbr->m[1]; k++) {

  1383.         for (i = i_Temp; i < i_f; i++) {

  1384.             X[0][i][k] = Y1[i][k][0];

  1385.             X[1][i][k] = Y1[i][k][1];

  1386.         }

  1387.     }

  1388.     return 0;

  1389. }

  1390. 

  1391. /** High Frequency Adjustment (14496-3 sp04 p217) and Mapping

  1392.  * (14496-3 sp04 p217)

  1393.  */

  1394. static void sbr_mapping(AACContext *ac, SpectralBandReplication *sbr,

  1395.                         SBRData *ch_data, int e_a[2])

  1396. {

  1397.     int e, i, m;

  1398. 

  1399.     memset(ch_data->s_indexmapped[1], 0, 7*sizeof(ch_data->s_indexmapped[1]));

  1400.     for (e = 0; e < ch_data->bs_num_env; e++) {

  1401.         const unsigned int ilim = sbr->n[ch_data->bs_freq_res[e + 1]];

  1402.         uint16_t *table = ch_data->bs_freq_res[e + 1] ? sbr->f_tablehigh : sbr->f_tablelow;

  1403.         int k;

  1404. 

  1405.         av_assert0(sbr->kx[1] <= table[0]);

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

  1407.             for (m = table[i]; m < table[i + 1]; m++)

  1408.                 sbr->e_origmapped[e][m - sbr->kx[1]] = ch_data->env_facs[e+1][i];

  1409. 

  1410.         // ch_data->bs_num_noise > 1 => 2 noise floors

  1411.         k = (ch_data->bs_num_noise > 1) && (ch_data->t_env[e] >= ch_data->t_q[1]);

  1412.         for (i = 0; i < sbr->n_q; i++)

  1413.             for (m = sbr->f_tablenoise[i]; m < sbr->f_tablenoise[i + 1]; m++)

  1414.                 sbr->q_mapped[e][m - sbr->kx[1]] = ch_data->noise_facs[k+1][i];

  1415. 

  1416.         for (i = 0; i < sbr->n[1]; i++) {

  1417.             if (ch_data->bs_add_harmonic_flag) {

  1418.                 const unsigned int m_midpoint =

  1419.                     (sbr->f_tablehigh[i] + sbr->f_tablehigh[i + 1]) >> 1;

  1420. 

  1421.                 ch_data->s_indexmapped[e + 1][m_midpoint - sbr->kx[1]] = ch_data->bs_add_harmonic[i] *

  1422.                     (e >= e_a[1] || (ch_data->s_indexmapped[0][m_midpoint - sbr->kx[1]] == 1));

  1423.             }

  1424.         }

  1425. 

  1426.         for (i = 0; i < ilim; i++) {

  1427.             int additional_sinusoid_present = 0;

  1428.             for (m = table[i]; m < table[i + 1]; m++) {

  1429.                 if (ch_data->s_indexmapped[e + 1][m - sbr->kx[1]]) {

  1430.                     additional_sinusoid_present = 1;

  1431.                     break;

  1432.                 }

  1433.             }

  1434.             memset(&sbr->s_mapped[e][table[i] - sbr->kx[1]], additional_sinusoid_present,

  1435.                    (table[i + 1] - table[i]) * sizeof(sbr->s_mapped[e][0]));

  1436.         }

  1437.     }

  1438. 

  1439.     memcpy(ch_data->s_indexmapped[0], ch_data->s_indexmapped[ch_data->bs_num_env], sizeof(ch_data->s_indexmapped[0]));

  1440. }

  1441. 

  1442. /// Estimation of current envelope (14496-3 sp04 p218)

  1443. static void sbr_env_estimate(float (*e_curr)[48], float X_high[64][40][2],

  1444.                              SpectralBandReplication *sbr, SBRData *ch_data)

  1445. {

  1446.     int e, m;

  1447.     int kx1 = sbr->kx[1];

  1448. 

  1449.     if (sbr->bs_interpol_freq) {

  1450.         for (e = 0; e < ch_data->bs_num_env; e++) {

  1451.             const float recip_env_size = 0.5f / (ch_data->t_env[e + 1] - ch_data->t_env[e]);

  1452.             int ilb = ch_data->t_env[e]     * 2 + ENVELOPE_ADJUSTMENT_OFFSET;

  1453.             int iub = ch_data->t_env[e + 1] * 2 + ENVELOPE_ADJUSTMENT_OFFSET;

  1454. 

  1455.             for (m = 0; m < sbr->m[1]; m++) {

  1456.                 float sum = sbr->dsp.sum_square(X_high[m+kx1] + ilb, iub - ilb);

  1457.                 e_curr[e][m] = sum * recip_env_size;

  1458.             }

  1459.         }

  1460.     } else {

  1461.         int k, p;

  1462. 

  1463.         for (e = 0; e < ch_data->bs_num_env; e++) {

  1464.             const int env_size = 2 * (ch_data->t_env[e + 1] - ch_data->t_env[e]);

  1465.             int ilb = ch_data->t_env[e]     * 2 + ENVELOPE_ADJUSTMENT_OFFSET;

  1466.             int iub = ch_data->t_env[e + 1] * 2 + ENVELOPE_ADJUSTMENT_OFFSET;

  1467.             const uint16_t *table = ch_data->bs_freq_res[e + 1] ? sbr->f_tablehigh : sbr->f_tablelow;

  1468. 

  1469.             for (p = 0; p < sbr->n[ch_data->bs_freq_res[e + 1]]; p++) {

  1470.                 float sum = 0.0f;

  1471.                 const int den = env_size * (table[p + 1] - table[p]);

  1472. 

  1473.                 for (k = table[p]; k < table[p + 1]; k++) {

  1474.                     sum += sbr->dsp.sum_square(X_high[k] + ilb, iub - ilb);

  1475.                 }

  1476.                 sum /= den;

  1477.                 for (k = table[p]; k < table[p + 1]; k++) {

  1478.                     e_curr[e][k - kx1] = sum;

  1479.                 }

  1480.             }

  1481.         }

  1482.     }

  1483. }

  1484. 

  1485. /**

  1486.  * Calculation of levels of additional HF signal components (14496-3 sp04 p219)

  1487.  * and Calculation of gain (14496-3 sp04 p219)

  1488.  */

  1489. static void sbr_gain_calc(AACContext *ac, SpectralBandReplication *sbr,

  1490.                           SBRData *ch_data, const int e_a[2])

  1491. {

  1492.     int e, k, m;

  1493.     // max gain limits : -3dB, 0dB, 3dB, inf dB (limiter off)

  1494.     static const float limgain[4] = { 0.70795, 1.0, 1.41254, 10000000000 };

  1495. 

  1496.     for (e = 0; e < ch_data->bs_num_env; e++) {

  1497.         int delta = !((e == e_a[1]) || (e == e_a[0]));

  1498.         for (k = 0; k < sbr->n_lim; k++) {

  1499.             float gain_boost, gain_max;

  1500.             float sum[2] = { 0.0f, 0.0f };

  1501.             for (m = sbr->f_tablelim[k] - sbr->kx[1]; m < sbr->f_tablelim[k + 1] - sbr->kx[1]; m++) {

  1502.                 const float temp = sbr->e_origmapped[e][m] / (1.0f + sbr->q_mapped[e][m]);

  1503.                 sbr->q_m[e][m] = sqrtf(temp * sbr->q_mapped[e][m]);

  1504.                 sbr->s_m[e][m] = sqrtf(temp * ch_data->s_indexmapped[e + 1][m]);

  1505.                 if (!sbr->s_mapped[e][m]) {

  1506.                     sbr->gain[e][m] = sqrtf(sbr->e_origmapped[e][m] /

  1507.                                             ((1.0f + sbr->e_curr[e][m]) *

  1508.                                              (1.0f + sbr->q_mapped[e][m] * delta)));

  1509.                 } else {

  1510.                     sbr->gain[e][m] = sqrtf(sbr->e_origmapped[e][m] * sbr->q_mapped[e][m] /

  1511.                                             ((1.0f + sbr->e_curr[e][m]) *

  1512.                                              (1.0f + sbr->q_mapped[e][m])));

  1513.                 }

  1514.             }

  1515.             for (m = sbr->f_tablelim[k] - sbr->kx[1]; m < sbr->f_tablelim[k + 1] - sbr->kx[1]; m++) {

  1516.                 sum[0] += sbr->e_origmapped[e][m];

  1517.                 sum[1] += sbr->e_curr[e][m];

  1518.             }

  1519.             gain_max = limgain[sbr->bs_limiter_gains] * sqrtf((FLT_EPSILON + sum[0]) / (FLT_EPSILON + sum[1]));

  1520.             gain_max = FFMIN(100000.f, gain_max);

  1521.             for (m = sbr->f_tablelim[k] - sbr->kx[1]; m < sbr->f_tablelim[k + 1] - sbr->kx[1]; m++) {

  1522.                 float q_m_max   = sbr->q_m[e][m] * gain_max / sbr->gain[e][m];

  1523.                 sbr->q_m[e][m]  = FFMIN(sbr->q_m[e][m], q_m_max);

  1524.                 sbr->gain[e][m] = FFMIN(sbr->gain[e][m], gain_max);

  1525.             }

  1526.             sum[0] = sum[1] = 0.0f;

  1527.             for (m = sbr->f_tablelim[k] - sbr->kx[1]; m < sbr->f_tablelim[k + 1] - sbr->kx[1]; m++) {

  1528.                 sum[0] += sbr->e_origmapped[e][m];

  1529.                 sum[1] += sbr->e_curr[e][m] * sbr->gain[e][m] * sbr->gain[e][m]

  1530.                           + sbr->s_m[e][m] * sbr->s_m[e][m]

  1531.                           + (delta && !sbr->s_m[e][m]) * sbr->q_m[e][m] * sbr->q_m[e][m];

  1532.             }

  1533.             gain_boost = sqrtf((FLT_EPSILON + sum[0]) / (FLT_EPSILON + sum[1]));

  1534.             gain_boost = FFMIN(1.584893192f, gain_boost);

  1535.             for (m = sbr->f_tablelim[k] - sbr->kx[1]; m < sbr->f_tablelim[k + 1] - sbr->kx[1]; m++) {

  1536.                 sbr->gain[e][m] *= gain_boost;

  1537.                 sbr->q_m[e][m]  *= gain_boost;

  1538.                 sbr->s_m[e][m]  *= gain_boost;

  1539.             }

  1540.         }

  1541.     }

  1542. }

  1543. 

  1544. /// Assembling HF Signals (14496-3 sp04 p220)

  1545. static void sbr_hf_assemble(float Y1[38][64][2],

  1546.                             const float X_high[64][40][2],

  1547.                             SpectralBandReplication *sbr, SBRData *ch_data,

  1548.                             const int e_a[2])

  1549. {

  1550.     int e, i, j, m;

  1551.     const int h_SL = 4 * !sbr->bs_smoothing_mode;

  1552.     const int kx = sbr->kx[1];

  1553.     const int m_max = sbr->m[1];

  1554.     static const float h_smooth[5] = {

  1555.         0.33333333333333,

  1556.         0.30150283239582,

  1557.         0.21816949906249,

  1558.         0.11516383427084,

  1559.         0.03183050093751,

  1560.     };

  1561.     static const int8_t phi[2][4] = {

  1562.         {  1,  0, -1,  0}, // real

  1563.         {  0,  1,  0, -1}, // imaginary

  1564.     };

  1565.     float (*g_temp)[48] = ch_data->g_temp, (*q_temp)[48] = ch_data->q_temp;

  1566.     int indexnoise = ch_data->f_indexnoise;

  1567.     int indexsine  = ch_data->f_indexsine;

  1568. 

  1569.     if (sbr->reset) {

  1570.         for (i = 0; i < h_SL; i++) {

  1571.             memcpy(g_temp[i + 2*ch_data->t_env[0]], sbr->gain[0], m_max * sizeof(sbr->gain[0][0]));

  1572.             memcpy(q_temp[i + 2*ch_data->t_env[0]], sbr->q_m[0],  m_max * sizeof(sbr->q_m[0][0]));

  1573.         }

  1574.     } else if (h_SL) {

  1575.         memcpy(g_temp[2*ch_data->t_env[0]], g_temp[2*ch_data->t_env_num_env_old], 4*sizeof(g_temp[0]));

  1576.         memcpy(q_temp[2*ch_data->t_env[0]], q_temp[2*ch_data->t_env_num_env_old], 4*sizeof(q_temp[0]));

  1577.     }

  1578. 

  1579.     for (e = 0; e < ch_data->bs_num_env; e++) {

  1580.         for (i = 2 * ch_data->t_env[e]; i < 2 * ch_data->t_env[e + 1]; i++) {

  1581.             memcpy(g_temp[h_SL + i], sbr->gain[e], m_max * sizeof(sbr->gain[0][0]));

  1582.             memcpy(q_temp[h_SL + i], sbr->q_m[e],  m_max * sizeof(sbr->q_m[0][0]));

  1583.         }

  1584.     }

  1585. 

  1586.     for (e = 0; e < ch_data->bs_num_env; e++) {

  1587.         for (i = 2 * ch_data->t_env[e]; i < 2 * ch_data->t_env[e + 1]; i++) {

  1588.             int phi_sign = (1 - 2*(kx & 1));

  1589.             LOCAL_ALIGNED_16(float, g_filt_tab, [48]);

  1590.             LOCAL_ALIGNED_16(float, q_filt_tab, [48]);

  1591.             float *g_filt, *q_filt;

  1592. 

  1593.             if (h_SL && e != e_a[0] && e != e_a[1]) {

  1594.                 g_filt = g_filt_tab;

  1595.                 q_filt = q_filt_tab;

  1596.                 for (m = 0; m < m_max; m++) {

  1597.                     const int idx1 = i + h_SL;

  1598.                     g_filt[m] = 0.0f;

  1599.                     q_filt[m] = 0.0f;

  1600.                     for (j = 0; j <= h_SL; j++) {

  1601.                         g_filt[m] += g_temp[idx1 - j][m] * h_smooth[j];

  1602.                         q_filt[m] += q_temp[idx1 - j][m] * h_smooth[j];

  1603.                     }

  1604.                 }

  1605.             } else {

  1606.                 g_filt = g_temp[i + h_SL];

  1607.                 q_filt = q_temp[i];

  1608.             }

  1609. 

  1610.             sbr->dsp.hf_g_filt(Y1[i] + kx, X_high + kx, g_filt, m_max,

  1611.                                i + ENVELOPE_ADJUSTMENT_OFFSET);

  1612. 

  1613.             if (e != e_a[0] && e != e_a[1]) {

  1614.                 sbr->dsp.hf_apply_noise[indexsine](Y1[i] + kx, sbr->s_m[e],

  1615.                                                    q_filt, indexnoise,

  1616.                                                    kx, m_max);

  1617.             } else {

  1618.                 for (m = 0; m < m_max; m++) {

  1619.                     Y1[i][m + kx][0] +=

  1620.                         sbr->s_m[e][m] * phi[0][indexsine];

  1621.                     Y1[i][m + kx][1] +=

  1622.                         sbr->s_m[e][m] * (phi[1][indexsine] * phi_sign);

  1623.                     phi_sign = -phi_sign;

  1624.                 }

  1625.             }

  1626.             indexnoise = (indexnoise + m_max) & 0x1ff;

  1627.             indexsine = (indexsine + 1) & 3;

  1628.         }

  1629.     }

  1630.     ch_data->f_indexnoise = indexnoise;

  1631.     ch_data->f_indexsine  = indexsine;

  1632. }

  1633. 

  1634. void ff_sbr_apply(AACContext *ac, SpectralBandReplication *sbr, int id_aac,

  1635.                   float* L, float* R)

  1636. {

  1637.     int downsampled = ac->m4ac.ext_sample_rate < sbr->sample_rate;

  1638.     int ch;

  1639.     int nch = (id_aac == TYPE_CPE) ? 2 : 1;

  1640. 

  1641.     if (sbr->start) {

  1642.         sbr_dequant(sbr, id_aac);

  1643.     }

  1644.     for (ch = 0; ch < nch; ch++) {

  1645.         /* decode channel */

  1646.         sbr_qmf_analysis(&ac->dsp, &sbr->mdct_ana, &sbr->dsp, ch ? R : L, sbr->data[ch].analysis_filterbank_samples,

  1647.                          (float*)sbr->qmf_filter_scratch,

  1648.                          sbr->data[ch].W);

  1649.         sbr_lf_gen(ac, sbr, sbr->X_low, sbr->data[ch].W);

  1650.         if (sbr->start) {

  1651.             sbr_hf_inverse_filter(&sbr->dsp, sbr->alpha0, sbr->alpha1, sbr->X_low, sbr->k[0]);

  1652.             sbr_chirp(sbr, &sbr->data[ch]);

  1653.             sbr_hf_gen(ac, sbr, sbr->X_high, sbr->X_low, sbr->alpha0, sbr->alpha1,

  1654.                        sbr->data[ch].bw_array, sbr->data[ch].t_env,

  1655.                        sbr->data[ch].bs_num_env);

  1656. 

  1657.             // hf_adj

  1658.             sbr_mapping(ac, sbr, &sbr->data[ch], sbr->data[ch].e_a);

  1659.             sbr_env_estimate(sbr->e_curr, sbr->X_high, sbr, &sbr->data[ch]);

  1660.             sbr_gain_calc(ac, sbr, &sbr->data[ch], sbr->data[ch].e_a);

  1661.             sbr->data[ch].Ypos ^= 1;

  1662.             sbr_hf_assemble(sbr->data[ch].Y[sbr->data[ch].Ypos],

  1663.                             sbr->X_high, sbr, &sbr->data[ch],

  1664.                             sbr->data[ch].e_a);

  1665.         }

  1666. 

  1667.         /* synthesis */

  1668.         sbr_x_gen(sbr, sbr->X[ch],

  1669.                   sbr->data[ch].Y[1-sbr->data[ch].Ypos],

  1670.                   sbr->data[ch].Y[  sbr->data[ch].Ypos],

  1671.                   sbr->X_low, ch);

  1672.     }

  1673. 

  1674.     if (ac->m4ac.ps == 1) {

  1675.         if (sbr->ps.start) {

  1676.             ff_ps_apply(ac->avctx, &sbr->ps, sbr->X[0], sbr->X[1], sbr->kx[1] + sbr->m[1]);

  1677.         } else {

  1678.             memcpy(sbr->X[1], sbr->X[0], sizeof(sbr->X[0]));

  1679.         }

  1680.         nch = 2;

  1681.     }

  1682. 

  1683.     sbr_qmf_synthesis(&ac->dsp, &sbr->mdct, &sbr->dsp, L, sbr->X[0], sbr->qmf_filter_scratch,

  1684.                       sbr->data[0].synthesis_filterbank_samples,

  1685.                       &sbr->data[0].synthesis_filterbank_samples_offset,

  1686.                       downsampled);

  1687.     if (nch == 2)

  1688.         sbr_qmf_synthesis(&ac->dsp, &sbr->mdct, &sbr->dsp, R, sbr->X[1], sbr->qmf_filter_scratch,

  1689.                           sbr->data[1].synthesis_filterbank_samples,

  1690.                           &sbr->data[1].synthesis_filterbank_samples_offset,

  1691.                           downsampled);

  1692. }