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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. 

  35. #include <stdint.h>

  36. #include <float.h>

  37. 

  38. #define ENVELOPE_ADJUSTMENT_OFFSET 2

  39. #define NOISE_FLOOR_OFFSET 6.0f

  40. 

  41. /**

  42.  * SBR VLC tables

  43.  */

  44. enum {

  45.     T_HUFFMAN_ENV_1_5DB,

  46.     F_HUFFMAN_ENV_1_5DB,

  47.     T_HUFFMAN_ENV_BAL_1_5DB,

  48.     F_HUFFMAN_ENV_BAL_1_5DB,

  49.     T_HUFFMAN_ENV_3_0DB,

  50.     F_HUFFMAN_ENV_3_0DB,

  51.     T_HUFFMAN_ENV_BAL_3_0DB,

  52.     F_HUFFMAN_ENV_BAL_3_0DB,

  53.     T_HUFFMAN_NOISE_3_0DB,

  54.     T_HUFFMAN_NOISE_BAL_3_0DB,

  55. };

  56. 

  57. /**

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

  59.  */

  60. enum {

  61.     FIXFIX,

  62.     FIXVAR,

  63.     VARFIX,

  64.     VARVAR,

  65. };

  66. 

  67. enum {

  68.     EXTENSION_ID_PS = 2,

  69. };

  70. 

  71. static VLC vlc_sbr[10];

  72. static const int8_t vlc_sbr_lav[10] =

  73.     { 60, 60, 24, 24, 31, 31, 12, 12, 31, 12 };

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

  75. 

  76. #define SBR_INIT_VLC_STATIC(num, size) \

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

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

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

  80.                     size)

  81. 

  82. #define SBR_VLC_ROW(name) \

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

  84. 

  85. av_cold void ff_aac_sbr_init(void)

  86. {

  87.     int n;

  88.     static const struct {

  89.         const void *sbr_codes, *sbr_bits;

  90.         const unsigned int table_size, elem_size;

  91.     } sbr_tmp[] = {

  92.         SBR_VLC_ROW(t_huffman_env_1_5dB),

  93.         SBR_VLC_ROW(f_huffman_env_1_5dB),

  94.         SBR_VLC_ROW(t_huffman_env_bal_1_5dB),

  95.         SBR_VLC_ROW(f_huffman_env_bal_1_5dB),

  96.         SBR_VLC_ROW(t_huffman_env_3_0dB),

  97.         SBR_VLC_ROW(f_huffman_env_3_0dB),

  98.         SBR_VLC_ROW(t_huffman_env_bal_3_0dB),

  99.         SBR_VLC_ROW(f_huffman_env_bal_3_0dB),

  100.         SBR_VLC_ROW(t_huffman_noise_3_0dB),

  101.         SBR_VLC_ROW(t_huffman_noise_bal_3_0dB),

  102.     };

  103. 

  104.     // SBR VLC table initialization

  105.     SBR_INIT_VLC_STATIC(0, 1098);

  106.     SBR_INIT_VLC_STATIC(1, 1092);

  107.     SBR_INIT_VLC_STATIC(2, 768);

  108.     SBR_INIT_VLC_STATIC(3, 1026);

  109.     SBR_INIT_VLC_STATIC(4, 1058);

  110.     SBR_INIT_VLC_STATIC(5, 1052);

  111.     SBR_INIT_VLC_STATIC(6, 544);

  112.     SBR_INIT_VLC_STATIC(7, 544);

  113.     SBR_INIT_VLC_STATIC(8, 592);

  114.     SBR_INIT_VLC_STATIC(9, 512);

  115. 

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

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

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

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

  120. 

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

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

  123. }

  124. 

  125. av_cold void ff_aac_sbr_ctx_init(SpectralBandReplication *sbr)

  126. {

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

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

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

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

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

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

  133. }

  134. 

  135. av_cold void ff_aac_sbr_ctx_close(SpectralBandReplication *sbr)

  136. {

  137.     ff_mdct_end(&sbr->mdct);

  138.     ff_mdct_end(&sbr->mdct_ana);

  139. }

  140. 

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

  142. {

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

  144. }

  145. 

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

  147. {

  148.     int i;

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

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

  151.             return 1;

  152.     return 0;

  153. }

  154. 

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

  156. static void sbr_make_f_tablelim(SpectralBandReplication *sbr)

  157. {

  158.     int k;

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

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

  161.                                                1.18509277094158210129f,   //2^(0.49/2)

  162.                                                1.11987160404675912501f }; //2^(0.49/3)

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

  164.         int16_t patch_borders[7];

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

  166. 

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

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

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

  170. 

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

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

  173.         if (sbr->num_patches > 1)

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

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

  176. 

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

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

  179.               qsort_comparison_function_int16);

  180. 

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

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

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

  184.                 *++out = *in++;

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

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

  187.                 in++;

  188.                 sbr->n_lim--;

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

  190.                 *out = *in++;

  191.                 sbr->n_lim--;

  192.             } else {

  193.                 *++out = *in++;

  194.             }

  195.         }

  196.     } else {

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

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

  199.         sbr->n_lim = 1;

  200.     }

  201. }

  202. 

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

  204. {

  205.     unsigned int cnt = get_bits_count(gb);

  206.     uint8_t bs_header_extra_1;

  207.     uint8_t bs_header_extra_2;

  208.     int old_bs_limiter_bands = sbr->bs_limiter_bands;

  209.     SpectrumParameters old_spectrum_params;

  210. 

  211.     sbr->start = 1;

  212. 

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

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

  215. 

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

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

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

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

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

  221. 

  222.     bs_header_extra_1 = get_bits1(gb);

  223.     bs_header_extra_2 = get_bits1(gb);

  224. 

  225.     if (bs_header_extra_1) {

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

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

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

  229.     } else {

  230.         sbr->spectrum_params.bs_freq_scale  = 2;

  231.         sbr->spectrum_params.bs_alter_scale = 1;

  232.         sbr->spectrum_params.bs_noise_bands = 2;

  233.     }

  234. 

  235.     // Check if spectrum parameters changed

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

  237.         sbr->reset = 1;

  238. 

  239.     if (bs_header_extra_2) {

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

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

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

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

  244.     } else {

  245.         sbr->bs_limiter_bands  = 2;

  246.         sbr->bs_limiter_gains  = 2;

  247.         sbr->bs_interpol_freq  = 1;

  248.         sbr->bs_smoothing_mode = 1;

  249.     }

  250. 

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

  252.         sbr_make_f_tablelim(sbr);

  253. 

  254.     return get_bits_count(gb) - cnt;

  255. }

  256. 

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

  258. {

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

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

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

  262.     return min;

  263. }

  264. 

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

  266. {

  267.     int k, previous, present;

  268.     float base, prod;

  269. 

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

  271.     prod = start;

  272.     previous = start;

  273. 

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

  275.         prod *= base;

  276.         present  = lrintf(prod);

  277.         bands[k] = present - previous;

  278.         previous = present;

  279.     }

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

  281. }

  282. 

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

  284. {

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

  286.     if (n_master <= 0) {

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

  288.         return -1;

  289.     }

  290.     if (bs_xover_band >= n_master) {

  291.         av_log(avctx, AV_LOG_ERROR,

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

  293.                bs_xover_band);

  294.         return -1;

  295.     }

  296.     return 0;

  297. }

  298. 

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

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

  301.                              SpectrumParameters *spectrum)

  302. {

  303.     unsigned int temp, max_qmf_subbands;

  304.     unsigned int start_min, stop_min;

  305.     int k;

  306.     const int8_t *sbr_offset_ptr;

  307.     int16_t stop_dk[13];

  308. 

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

  310.         temp = 3000;

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

  312.         temp = 4000;

  313.     } else

  314.         temp = 5000;

  315. 

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

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

  318. 

  319.     switch (sbr->sample_rate) {

  320.     case 16000:

  321.         sbr_offset_ptr = sbr_offset[0];

  322.         break;

  323.     case 22050:

  324.         sbr_offset_ptr = sbr_offset[1];

  325.         break;

  326.     case 24000:

  327.         sbr_offset_ptr = sbr_offset[2];

  328.         break;

  329.     case 32000:

  330.         sbr_offset_ptr = sbr_offset[3];

  331.         break;

  332.     case 44100: case 48000: case 64000:

  333.         sbr_offset_ptr = sbr_offset[4];

  334.         break;

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

  336.         sbr_offset_ptr = sbr_offset[5];

  337.         break;

  338.     default:

  339.         av_log(ac->avctx, AV_LOG_ERROR,

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

  341.         return -1;

  342.     }

  343. 

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

  345. 

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

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

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

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

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

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

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

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

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

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

  356.     } else {

  357.         av_log(ac->avctx, AV_LOG_ERROR,

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

  359.         return -1;

  360.     }

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

  362. 

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

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

  365.         max_qmf_subbands = 48;

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

  367.         max_qmf_subbands = 35;

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

  369.         max_qmf_subbands = 32;

  370. 

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

  372.         av_log(ac->avctx, AV_LOG_ERROR,

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

  374.         return -1;

  375.     }

  376. 

  377.     if (!spectrum->bs_freq_scale) {

  378.         unsigned int dk;

  379.         int k2diff;

  380. 

  381.         dk = spectrum->bs_alter_scale + 1;

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

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

  384.             return -1;

  385. 

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

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

  388. 

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

  390.         if (k2diff < 0) {

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

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

  393.         } else if (k2diff) {

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

  395.         }

  396. 

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

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

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

  400. 

  401.     } else {

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

  403.         int two_regions, num_bands_0;

  404.         int vdk0_max, vdk1_min;

  405.         int16_t vk0[49];

  406. 

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

  408.             two_regions = 1;

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

  410.         } else {

  411.             two_regions = 0;

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

  413.         }

  414. 

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

  416. 

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

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

  419.             return -1;

  420.         }

  421. 

  422.         vk0[0] = 0;

  423. 

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

  425. 

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

  427.         vdk0_max = vk0[num_bands_0];

  428. 

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

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

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

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

  433.                 return -1;

  434.             }

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

  436.         }

  437. 

  438.         if (two_regions) {

  439.             int16_t vk1[49];

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

  441.                                                      : 1.0f; // bs_alter_scale = {0,1}

  442.             int num_bands_1 = lrintf(half_bands * invwarp *

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

  444. 

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

  446. 

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

  448. 

  449.             if (vdk1_min < vdk0_max) {

  450.                 int change;

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

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

  453.                 vk1[1]           += change;

  454.                 vk1[num_bands_1] -= change;

  455.             }

  456. 

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

  458. 

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

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

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

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

  463.                     return -1;

  464.                 }

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

  466.             }

  467. 

  468.             sbr->n_master = num_bands_0 + num_bands_1;

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

  470.                 return -1;

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

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

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

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

  475. 

  476.         } else {

  477.             sbr->n_master = num_bands_0;

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

  479.                 return -1;

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

  481.         }

  482.     }

  483. 

  484.     return 0;

  485. }

  486. 

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

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

  489. {

  490.     int i, k, sb = 0;

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

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

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

  494. 

  495.     sbr->num_patches = 0;

  496. 

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

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

  499.     } else

  500.         k = sbr->n_master;

  501. 

  502.     do {

  503.         int odd = 0;

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

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

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

  507.         }

  508. 

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

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

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

  512.         // count of 6 patches

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

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

  515.             return -1;

  516.         }

  517. 

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

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

  520. 

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

  522.             usb = sb;

  523.             msb = sb;

  524.             sbr->num_patches++;

  525.         } else

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

  527. 

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

  529.             k = sbr->n_master;

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

  531. 

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

  533.         sbr->num_patches--;

  534. 

  535.     return 0;

  536. }

  537. 

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

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

  540. {

  541.     int k, temp;

  542. 

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

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

  545. 

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

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

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

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

  550. 

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

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

  553.         av_log(ac->avctx, AV_LOG_ERROR,

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

  555.         return -1;

  556.     }

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

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

  559.         return -1;

  560.     }

  561. 

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

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

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

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

  566. 

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

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

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

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

  571.         return -1;

  572.     }

  573. 

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

  575.     temp = 0;

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

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

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

  579.     }

  580. 

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

  582.         return -1;

  583. 

  584.     sbr_make_f_tablelim(sbr);

  585. 

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

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

  588. 

  589.     return 0;

  590. }

  591. 

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

  593.                                               int elements)

  594. {

  595.     int i;

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

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

  598.     }

  599. }

  600. 

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

  602. static const int8_t ceil_log2[] = {

  603.     0, 1, 2, 2, 3, 3,

  604. };

  605. 

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

  607.                          GetBitContext *gb, SBRData *ch_data)

  608. {

  609.     int i;

  610.     unsigned bs_pointer = 0;

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

  612.     int abs_bord_trail = 16;

  613.     int num_rel_lead, num_rel_trail;

  614.     unsigned bs_num_env_old = ch_data->bs_num_env;

  615. 

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

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

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

  619. 

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

  621.     case FIXFIX:

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

  623.         num_rel_lead                        = ch_data->bs_num_env - 1;

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

  625.             ch_data->bs_amp_res = 0;

  626. 

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

  628.             av_log(ac->avctx, AV_LOG_ERROR,

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

  630.                    ch_data->bs_num_env);

  631.             return -1;

  632.         }

  633. 

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

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

  636. 

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

  638.                    ch_data->bs_num_env;

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

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

  641. 

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

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

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

  645.         break;

  646.     case FIXVAR:

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

  648.         num_rel_trail                       = get_bits(gb, 2);

  649.         ch_data->bs_num_env                 = num_rel_trail + 1;

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

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

  652. 

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

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

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

  656. 

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

  658. 

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

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

  661.         break;

  662.     case VARFIX:

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

  664.         num_rel_lead                        = get_bits(gb, 2);

  665.         ch_data->bs_num_env                 = num_rel_lead + 1;

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

  667. 

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

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

  670. 

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

  672. 

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

  674.         break;

  675.     case VARVAR:

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

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

  678.         num_rel_lead                        = get_bits(gb, 2);

  679.         num_rel_trail                       = get_bits(gb, 2);

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

  681. 

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

  683.             av_log(ac->avctx, AV_LOG_ERROR,

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

  685.                    ch_data->bs_num_env);

  686.             return -1;

  687.         }

  688. 

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

  690. 

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

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

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

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

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

  696. 

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

  698. 

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

  700.         break;

  701.     }

  702. 

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

  704.         av_log(ac->avctx, AV_LOG_ERROR,

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

  706.                bs_pointer);

  707.         return -1;

  708.     }

  709. 

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

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

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

  713.             return -1;

  714.         }

  715.     }

  716. 

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

  718. 

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

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

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

  722.         unsigned int idx;

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

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

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

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

  727.         } else { // VARFIX

  728.             if (!bs_pointer)

  729.                 idx = 1;

  730.             else if (bs_pointer == 1)

  731.                 idx = ch_data->bs_num_env - 1;

  732.             else // bs_pointer > 1

  733.                 idx = bs_pointer - 1;

  734.         }

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

  736.     }

  737. 

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

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

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

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

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

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

  744. 

  745.     return 0;

  746. }

  747. 

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

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

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

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

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

  753. 

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

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

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

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

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

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

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

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

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

  763. }

  764. 

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

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

  767.                           SBRData *ch_data)

  768. {

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

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

  771. }

  772. 

  773. /// Read inverse filtering data

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

  775.                           SBRData *ch_data)

  776. {

  777.     int i;

  778. 

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

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

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

  782. }

  783. 

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

  785.                               SBRData *ch_data, int ch)

  786. {

  787.     int bits;

  788.     int i, j, k;

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

  790.     int t_lav, f_lav;

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

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

  793. 

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

  795.         if (ch_data->bs_amp_res) {

  796.             bits   = 5;

  797.             t_huff = vlc_sbr[T_HUFFMAN_ENV_BAL_3_0DB].table;

  798.             t_lav  = vlc_sbr_lav[T_HUFFMAN_ENV_BAL_3_0DB];

  799.             f_huff = vlc_sbr[F_HUFFMAN_ENV_BAL_3_0DB].table;

  800.             f_lav  = vlc_sbr_lav[F_HUFFMAN_ENV_BAL_3_0DB];

  801.         } else {

  802.             bits   = 6;

  803.             t_huff = vlc_sbr[T_HUFFMAN_ENV_BAL_1_5DB].table;

  804.             t_lav  = vlc_sbr_lav[T_HUFFMAN_ENV_BAL_1_5DB];

  805.             f_huff = vlc_sbr[F_HUFFMAN_ENV_BAL_1_5DB].table;

  806.             f_lav  = vlc_sbr_lav[F_HUFFMAN_ENV_BAL_1_5DB];

  807.         }

  808.     } else {

  809.         if (ch_data->bs_amp_res) {

  810.             bits   = 6;

  811.             t_huff = vlc_sbr[T_HUFFMAN_ENV_3_0DB].table;

  812.             t_lav  = vlc_sbr_lav[T_HUFFMAN_ENV_3_0DB];

  813.             f_huff = vlc_sbr[F_HUFFMAN_ENV_3_0DB].table;

  814.             f_lav  = vlc_sbr_lav[F_HUFFMAN_ENV_3_0DB];

  815.         } else {

  816.             bits   = 7;

  817.             t_huff = vlc_sbr[T_HUFFMAN_ENV_1_5DB].table;

  818.             t_lav  = vlc_sbr_lav[T_HUFFMAN_ENV_1_5DB];

  819.             f_huff = vlc_sbr[F_HUFFMAN_ENV_1_5DB].table;

  820.             f_lav  = vlc_sbr_lav[F_HUFFMAN_ENV_1_5DB];

  821.         }

  822.     }

  823. 

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

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

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

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

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

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

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

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

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

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

  834.                 }

  835.             } else {

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

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

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

  839.                 }

  840.             }

  841.         } else {

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

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

  844.                 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);

  845.         }

  846.     }

  847. 

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

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

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

  851. }

  852. 

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

  854.                            SBRData *ch_data, int ch)

  855. {

  856.     int i, j;

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

  858.     int t_lav, f_lav;

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

  860. 

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

  862.         t_huff = vlc_sbr[T_HUFFMAN_NOISE_BAL_3_0DB].table;

  863.         t_lav  = vlc_sbr_lav[T_HUFFMAN_NOISE_BAL_3_0DB];

  864.         f_huff = vlc_sbr[F_HUFFMAN_ENV_BAL_3_0DB].table;

  865.         f_lav  = vlc_sbr_lav[F_HUFFMAN_ENV_BAL_3_0DB];

  866.     } else {

  867.         t_huff = vlc_sbr[T_HUFFMAN_NOISE_3_0DB].table;

  868.         t_lav  = vlc_sbr_lav[T_HUFFMAN_NOISE_3_0DB];

  869.         f_huff = vlc_sbr[F_HUFFMAN_ENV_3_0DB].table;

  870.         f_lav  = vlc_sbr_lav[F_HUFFMAN_ENV_3_0DB];

  871.     }

  872. 

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

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

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

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

  877.         } else {

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

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

  880.                 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);

  881.         }

  882.     }

  883. 

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

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

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

  887. }

  888. 

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

  890.                                GetBitContext *gb,

  891.                                int bs_extension_id, int *num_bits_left)

  892. {

  893. //TODO - implement ps_data for parametric stereo parsing

  894.     switch (bs_extension_id) {

  895.     case EXTENSION_ID_PS:

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

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

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

  899.             *num_bits_left = 0;

  900.         } else {

  901. #if 0

  902.             *num_bits_left -= ff_ps_data(gb, ps);

  903. #else

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

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

  906.             *num_bits_left = 0;

  907. #endif

  908.         }

  909.         break;

  910.     default:

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

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

  913.         *num_bits_left = 0;

  914.         break;

  915.     }

  916. }

  917. 

  918. static int read_sbr_single_channel_element(AACContext *ac,

  919.                                             SpectralBandReplication *sbr,

  920.                                             GetBitContext *gb)

  921. {

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

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

  924. 

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

  926.         return -1;

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

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

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

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

  931. 

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

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

  934. 

  935.     return 0;

  936. }

  937. 

  938. static int read_sbr_channel_pair_element(AACContext *ac,

  939.                                           SpectralBandReplication *sbr,

  940.                                           GetBitContext *gb)

  941. {

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

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

  944. 

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

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

  947.             return -1;

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

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

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

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

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

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

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

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

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

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

  958.     } else {

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

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

  961.             return -1;

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

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

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

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

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

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

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

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

  970.     }

  971. 

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

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

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

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

  976. 

  977.     return 0;

  978. }

  979. 

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

  981.                                   GetBitContext *gb, int id_aac)

  982. {

  983.     unsigned int cnt = get_bits_count(gb);

  984. 

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

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

  987.             sbr->start = 0;

  988.             return get_bits_count(gb) - cnt;

  989.         }

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

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

  992.             sbr->start = 0;

  993.             return get_bits_count(gb) - cnt;

  994.         }

  995.     } else {

  996.         av_log(ac->avctx, AV_LOG_ERROR,

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

  998.         sbr->start = 0;

  999.         return get_bits_count(gb) - cnt;

  1000.     }

  1001.     if (get_bits1(gb)) { // bs_extended_data

  1002.         int num_bits_left = get_bits(gb, 4); // bs_extension_size

  1003.         if (num_bits_left == 15)

  1004.             num_bits_left += get_bits(gb, 8); // bs_esc_count

  1005. 

  1006.         num_bits_left <<= 3;

  1007.         while (num_bits_left > 7) {

  1008.             num_bits_left -= 2;

  1009.             read_sbr_extension(ac, sbr, gb, get_bits(gb, 2), &num_bits_left); // bs_extension_id

  1010.         }

  1011.     }

  1012. 

  1013.     return get_bits_count(gb) - cnt;

  1014. }

  1015. 

  1016. static void sbr_reset(AACContext *ac, SpectralBandReplication *sbr)

  1017. {

  1018.     int err;

  1019.     err = sbr_make_f_master(ac, sbr, &sbr->spectrum_params);

  1020.     if (err >= 0)

  1021.         err = sbr_make_f_derived(ac, sbr);

  1022.     if (err < 0) {

  1023.         av_log(ac->avctx, AV_LOG_ERROR,

  1024.                "SBR reset failed. Switching SBR to pure upsampling mode.\n");

  1025.         sbr->start = 0;

  1026.     }

  1027. }

  1028. 

  1029. /**

  1030.  * Decode Spectral Band Replication extension data; reference: table 4.55.

  1031.  *

  1032.  * @param   crc flag indicating the presence of CRC checksum

  1033.  * @param   cnt length of TYPE_FIL syntactic element in bytes

  1034.  *

  1035.  * @return  Returns number of bytes consumed from the TYPE_FIL element.

  1036.  */

  1037. int ff_decode_sbr_extension(AACContext *ac, SpectralBandReplication *sbr,

  1038.                             GetBitContext *gb_host, int crc, int cnt, int id_aac)

  1039. {

  1040.     unsigned int num_sbr_bits = 0, num_align_bits;

  1041.     unsigned bytes_read;

  1042.     GetBitContext gbc = *gb_host, *gb = &gbc;

  1043.     skip_bits_long(gb_host, cnt*8 - 4);

  1044. 

  1045.     sbr->reset = 0;

  1046. 

  1047.     if (!sbr->sample_rate)

  1048.         sbr->sample_rate = 2 * ac->m4ac.sample_rate; //TODO use the nominal sample rate for arbitrary sample rate support

  1049.     if (!ac->m4ac.ext_sample_rate)

  1050.         ac->m4ac.ext_sample_rate = 2 * ac->m4ac.sample_rate;

  1051. 

  1052.     if (crc) {

  1053.         skip_bits(gb, 10); // bs_sbr_crc_bits; TODO - implement CRC check

  1054.         num_sbr_bits += 10;

  1055.     }

  1056. 

  1057.     //Save some state from the previous frame.

  1058.     sbr->kx[0] = sbr->kx[1];

  1059.     sbr->m[0] = sbr->m[1];

  1060. 

  1061.     num_sbr_bits++;

  1062.     if (get_bits1(gb)) // bs_header_flag

  1063.         num_sbr_bits += read_sbr_header(sbr, gb);

  1064. 

  1065.     if (sbr->reset)

  1066.         sbr_reset(ac, sbr);

  1067. 

  1068.     if (sbr->start)

  1069.         num_sbr_bits  += read_sbr_data(ac, sbr, gb, id_aac);

  1070. 

  1071.     num_align_bits = ((cnt << 3) - 4 - num_sbr_bits) & 7;

  1072.     bytes_read = ((num_sbr_bits + num_align_bits + 4) >> 3);

  1073. 

  1074.     if (bytes_read > cnt) {

  1075.         av_log(ac->avctx, AV_LOG_ERROR,

  1076.                "Expected to read %d SBR bytes actually read %d.\n", cnt, bytes_read);

  1077.     }

  1078.     return cnt;

  1079. }

  1080. 

  1081. /// Dequantization and stereo decoding (14496-3 sp04 p203)

  1082. static void sbr_dequant(SpectralBandReplication *sbr, int id_aac)

  1083. {

  1084.     int k, e;

  1085.     int ch;

  1086. 

  1087.     if (id_aac == TYPE_CPE && sbr->bs_coupling) {

  1088.         float alpha      = sbr->data[0].bs_amp_res ?  1.0f :  0.5f;

  1089.         float pan_offset = sbr->data[0].bs_amp_res ? 12.0f : 24.0f;

  1090.         for (e = 1; e <= sbr->data[0].bs_num_env; e++) {

  1091.             for (k = 0; k < sbr->n[sbr->data[0].bs_freq_res[e]]; k++) {

  1092.                 float temp1 = exp2f(sbr->data[0].env_facs[e][k] * alpha + 7.0f);

  1093.                 float temp2 = exp2f((pan_offset - sbr->data[1].env_facs[e][k]) * alpha);

  1094.                 float fac   = temp1 / (1.0f + temp2);

  1095.                 sbr->data[0].env_facs[e][k] = fac;

  1096.                 sbr->data[1].env_facs[e][k] = fac * temp2;

  1097.             }

  1098.         }

  1099.         for (e = 1; e <= sbr->data[0].bs_num_noise; e++) {

  1100.             for (k = 0; k < sbr->n_q; k++) {

  1101.                 float temp1 = exp2f(NOISE_FLOOR_OFFSET - sbr->data[0].noise_facs[e][k] + 1);

  1102.                 float temp2 = exp2f(12 - sbr->data[1].noise_facs[e][k]);

  1103.                 float fac   = temp1 / (1.0f + temp2);

  1104.                 sbr->data[0].noise_facs[e][k] = fac;

  1105.                 sbr->data[1].noise_facs[e][k] = fac * temp2;

  1106.             }

  1107.         }

  1108.     } else { // SCE or one non-coupled CPE

  1109.         for (ch = 0; ch < (id_aac == TYPE_CPE) + 1; ch++) {

  1110.             float alpha = sbr->data[ch].bs_amp_res ? 1.0f : 0.5f;

  1111.             for (e = 1; e <= sbr->data[ch].bs_num_env; e++)

  1112.                 for (k = 0; k < sbr->n[sbr->data[ch].bs_freq_res[e]]; k++)

  1113.                     sbr->data[ch].env_facs[e][k] =

  1114.                         exp2f(alpha * sbr->data[ch].env_facs[e][k] + 6.0f);

  1115.             for (e = 1; e <= sbr->data[ch].bs_num_noise; e++)

  1116.                 for (k = 0; k < sbr->n_q; k++)

  1117.                     sbr->data[ch].noise_facs[e][k] =

  1118.                         exp2f(NOISE_FLOOR_OFFSET - sbr->data[ch].noise_facs[e][k]);

  1119.         }

  1120.     }

  1121. }

  1122. 

  1123. /**

  1124.  * Analysis QMF Bank (14496-3 sp04 p206)

  1125.  *

  1126.  * @param   x       pointer to the beginning of the first sample window

  1127.  * @param   W       array of complex-valued samples split into subbands

  1128.  */

  1129. static void sbr_qmf_analysis(DSPContext *dsp, FFTContext *mdct, const float *in, float *x,

  1130.                              float z[320], float W[2][32][32][2],

  1131.                              float scale)

  1132. {

  1133.     int i, k;

  1134.     memcpy(W[0], W[1], sizeof(W[0]));

  1135.     memcpy(x    , x+1024, (320-32)*sizeof(x[0]));

  1136.     if (scale != 1.0f)

  1137.         dsp->vector_fmul_scalar(x+288, in, scale, 1024);

  1138.     else

  1139.         memcpy(x+288, in, 1024*sizeof(*x));

  1140.     for (i = 0; i < 32; i++) { // numTimeSlots*RATE = 16*2 as 960 sample frames

  1141.                                // are not supported

  1142.         dsp->vector_fmul_reverse(z, sbr_qmf_window_ds, x, 320);

  1143.         for (k = 0; k < 64; k++) {

  1144.             float f = z[k] + z[k + 64] + z[k + 128] + z[k + 192] + z[k + 256];

  1145.             z[k] = f;

  1146.         }

  1147.         //Shuffle to IMDCT

  1148.         z[64] = z[0];

  1149.         for (k = 1; k < 32; k++) {

  1150.             z[64+2*k-1] =  z[   k];

  1151.             z[64+2*k  ] = -z[64-k];

  1152.         }

  1153.         z[64+63] = z[32];

  1154. 

  1155.         ff_imdct_half(mdct, z, z+64);

  1156.         for (k = 0; k < 32; k++) {

  1157.             W[1][i][k][0] = -z[63-k];

  1158.             W[1][i][k][1] = z[k];

  1159.         }

  1160.         x += 32;

  1161.     }

  1162. }

  1163. 

  1164. /**

  1165.  * Synthesis QMF Bank (14496-3 sp04 p206) and Downsampled Synthesis QMF Bank

  1166.  * (14496-3 sp04 p206)

  1167.  */

  1168. static void sbr_qmf_synthesis(DSPContext *dsp, FFTContext *mdct,

  1169.                               float *out, float X[2][32][64],

  1170.                               float mdct_buf[2][64],

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

  1172.                               float bias, float scale)

  1173. {

  1174.     int i, n;

  1175.     const float *sbr_qmf_window = div ? sbr_qmf_window_ds : sbr_qmf_window_us;

  1176.     int scale_and_bias = scale != 1.0f || bias != 0.0f;

  1177.     float *v;

  1178.     for (i = 0; i < 32; i++) {

  1179.         if (*v_off == 0) {

  1180.             int saved_samples = (1280 - 128) >> div;

  1181.             memcpy(&v0[SBR_SYNTHESIS_BUF_SIZE - saved_samples], v0, saved_samples * sizeof(float));

  1182.             *v_off = SBR_SYNTHESIS_BUF_SIZE - saved_samples - (128 >> div);

  1183.         } else {

  1184.             *v_off -= 128 >> div;

  1185.         }

  1186.         v = v0 + *v_off;

  1187.         if (div) {

  1188.             for (n = 0; n < 32; n++) {

  1189.                 X[0][i][   n] = -X[0][i][n];

  1190.                 X[0][i][32+n] =  X[1][i][31-n];

  1191.             }

  1192.             ff_imdct_half(mdct, mdct_buf[0], X[0][i]);

  1193.             for (n = 0; n < 32; n++) {

  1194.                 v[     n] =  mdct_buf[0][63 - 2*n];

  1195.                 v[63 - n] = -mdct_buf[0][62 - 2*n];

  1196.             }

  1197.         } else {

  1198.             for (n = 1; n < 64; n+=2) {

  1199.                 X[1][i][n] = -X[1][i][n];

  1200.             }

  1201.             ff_imdct_half(mdct, mdct_buf[0], X[0][i]);

  1202.             ff_imdct_half(mdct, mdct_buf[1], X[1][i]);

  1203.             for (n = 0; n < 64; n++) {

  1204.                 v[      n] = -mdct_buf[0][63 -   n] + mdct_buf[1][  n    ];

  1205.                 v[127 - n] =  mdct_buf[0][63 -   n] + mdct_buf[1][  n    ];

  1206.             }

  1207.         }

  1208.         dsp->vector_fmul_add(out, v                , sbr_qmf_window               , zero64, 64 >> div);

  1209.         dsp->vector_fmul_add(out, v + ( 192 >> div), sbr_qmf_window + ( 64 >> div), out   , 64 >> div);

  1210.         dsp->vector_fmul_add(out, v + ( 256 >> div), sbr_qmf_window + (128 >> div), out   , 64 >> div);

  1211.         dsp->vector_fmul_add(out, v + ( 448 >> div), sbr_qmf_window + (192 >> div), out   , 64 >> div);

  1212.         dsp->vector_fmul_add(out, v + ( 512 >> div), sbr_qmf_window + (256 >> div), out   , 64 >> div);

  1213.         dsp->vector_fmul_add(out, v + ( 704 >> div), sbr_qmf_window + (320 >> div), out   , 64 >> div);

  1214.         dsp->vector_fmul_add(out, v + ( 768 >> div), sbr_qmf_window + (384 >> div), out   , 64 >> div);

  1215.         dsp->vector_fmul_add(out, v + ( 960 >> div), sbr_qmf_window + (448 >> div), out   , 64 >> div);

  1216.         dsp->vector_fmul_add(out, v + (1024 >> div), sbr_qmf_window + (512 >> div), out   , 64 >> div);

  1217.         dsp->vector_fmul_add(out, v + (1216 >> div), sbr_qmf_window + (576 >> div), out   , 64 >> div);

  1218.         if (scale_and_bias)

  1219.             for (n = 0; n < 64 >> div; n++)

  1220.                 out[n] = out[n] * scale + bias;

  1221.         out += 64 >> div;

  1222.     }

  1223. }

  1224. 

  1225. static void autocorrelate(const float x[40][2], float phi[3][2][2], int lag)

  1226. {

  1227.     int i;

  1228.     float real_sum = 0.0f;

  1229.     float imag_sum = 0.0f;

  1230.     if (lag) {

  1231.         for (i = 1; i < 38; i++) {

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

  1233.             imag_sum += x[i][0] * x[i+lag][1] - x[i][1] * x[i+lag][0];

  1234.         }

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

  1236.         phi[2-lag][1][1] = imag_sum + x[ 0][0] * x[lag][1] - x[ 0][1] * x[lag][0];

  1237.         if (lag == 1) {

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

  1239.             phi[0][0][1] = imag_sum + x[38][0] * x[39][1] - x[38][1] * x[39][0];

  1240.         }

  1241.     } else {

  1242.         for (i = 1; i < 38; i++) {

  1243.             real_sum += x[i][0] * x[i][0] + x[i][1] * x[i][1];

  1244.         }

  1245.         phi[2][1][0] = real_sum + x[ 0][0] * x[ 0][0] + x[ 0][1] * x[ 0][1];

  1246.         phi[1][0][0] = real_sum + x[38][0] * x[38][0] + x[38][1] * x[38][1];

  1247.     }

  1248. }

  1249. 

  1250. /** High Frequency Generation (14496-3 sp04 p214+) and Inverse Filtering

  1251.  * (14496-3 sp04 p214)

  1252.  * Warning: This routine does not seem numerically stable.

  1253.  */

  1254. static void sbr_hf_inverse_filter(float (*alpha0)[2], float (*alpha1)[2],

  1255.                                   const float X_low[32][40][2], int k0)

  1256. {

  1257.     int k;

  1258.     for (k = 0; k < k0; k++) {

  1259.         float phi[3][2][2], dk;

  1260. 

  1261.         autocorrelate(X_low[k], phi, 0);

  1262.         autocorrelate(X_low[k], phi, 1);

  1263.         autocorrelate(X_low[k], phi, 2);

  1264. 

  1265.         dk =  phi[2][1][0] * phi[1][0][0] -

  1266.              (phi[1][1][0] * phi[1][1][0] + phi[1][1][1] * phi[1][1][1]) / 1.000001f;

  1267. 

  1268.         if (!dk) {

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

  1270.             alpha1[k][1] = 0;

  1271.         } else {

  1272.             float temp_real, temp_im;

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

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

  1275.                         phi[0][1][0] * phi[1][0][0];

  1276.             temp_im   = phi[0][0][0] * phi[1][1][1] +

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

  1278.                         phi[0][1][1] * phi[1][0][0];

  1279. 

  1280.             alpha1[k][0] = temp_real / dk;

  1281.             alpha1[k][1] = temp_im   / dk;

  1282.         }

  1283. 

  1284.         if (!phi[1][0][0]) {

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

  1286.             alpha0[k][1] = 0;

  1287.         } else {

  1288.             float temp_real, temp_im;

  1289.             temp_real = phi[0][0][0] + alpha1[k][0] * phi[1][1][0] +

  1290.                                        alpha1[k][1] * phi[1][1][1];

  1291.             temp_im   = phi[0][0][1] + alpha1[k][1] * phi[1][1][0] -

  1292.                                        alpha1[k][0] * phi[1][1][1];

  1293. 

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

  1295.             alpha0[k][1] = -temp_im   / phi[1][0][0];

  1296.         }

  1297. 

  1298.         if (alpha1[k][0] * alpha1[k][0] + alpha1[k][1] * alpha1[k][1] >= 16.0f ||

  1299.            alpha0[k][0] * alpha0[k][0] + alpha0[k][1] * alpha0[k][1] >= 16.0f) {

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

  1301.             alpha1[k][1] = 0;

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

  1303.             alpha0[k][1] = 0;

  1304.         }

  1305.     }

  1306. }

  1307. 

  1308. /// Chirp Factors (14496-3 sp04 p214)

  1309. static void sbr_chirp(SpectralBandReplication *sbr, SBRData *ch_data)

  1310. {

  1311.     int i;

  1312.     float new_bw;

  1313.     static const float bw_tab[] = { 0.0f, 0.75f, 0.9f, 0.98f };

  1314. 

  1315.     for (i = 0; i < sbr->n_q; i++) {

  1316.         if (ch_data->bs_invf_mode[0][i] + ch_data->bs_invf_mode[1][i] == 1) {

  1317.             new_bw = 0.6f;

  1318.         } else

  1319.             new_bw = bw_tab[ch_data->bs_invf_mode[0][i]];

  1320. 

  1321.         if (new_bw < ch_data->bw_array[i]) {

  1322.             new_bw = 0.75f    * new_bw + 0.25f    * ch_data->bw_array[i];

  1323.         } else

  1324.             new_bw = 0.90625f * new_bw + 0.09375f * ch_data->bw_array[i];

  1325.         ch_data->bw_array[i] = new_bw < 0.015625f ? 0.0f : new_bw;

  1326.     }

  1327. }

  1328. 

  1329. /// Generate the subband filtered lowband

  1330. static int sbr_lf_gen(AACContext *ac, SpectralBandReplication *sbr,

  1331.                       float X_low[32][40][2], const float W[2][32][32][2])

  1332. {

  1333.     int i, k;

  1334.     const int t_HFGen = 8;

  1335.     const int i_f = 32;

  1336.     memset(X_low, 0, 32*sizeof(*X_low));

  1337.     for (k = 0; k < sbr->kx[1]; k++) {

  1338.         for (i = t_HFGen; i < i_f + t_HFGen; i++) {

  1339.             X_low[k][i][0] = W[1][i - t_HFGen][k][0];

  1340.             X_low[k][i][1] = W[1][i - t_HFGen][k][1];

  1341.         }

  1342.     }

  1343.     for (k = 0; k < sbr->kx[0]; k++) {

  1344.         for (i = 0; i < t_HFGen; i++) {

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

  1346.             X_low[k][i][1] = W[0][i + i_f - t_HFGen][k][1];

  1347.         }

  1348.     }

  1349.     return 0;

  1350. }

  1351. 

  1352. /// High Frequency Generator (14496-3 sp04 p215)

  1353. static int sbr_hf_gen(AACContext *ac, SpectralBandReplication *sbr,

  1354.                       float X_high[64][40][2], const float X_low[32][40][2],

  1355.                       const float (*alpha0)[2], const float (*alpha1)[2],

  1356.                       const float bw_array[5], const uint8_t *t_env,

  1357.                       int bs_num_env)

  1358. {

  1359.     int i, j, x;

  1360.     int g = 0;

  1361.     int k = sbr->kx[1];

  1362.     for (j = 0; j < sbr->num_patches; j++) {

  1363.         for (x = 0; x < sbr->patch_num_subbands[j]; x++, k++) {

  1364.             float alpha[4];

  1365.             const int p = sbr->patch_start_subband[j] + x;

  1366.             while (g <= sbr->n_q && k >= sbr->f_tablenoise[g])

  1367.                 g++;

  1368.             g--;

  1369. 

  1370.             if (g < 0) {

  1371.                 av_log(ac->avctx, AV_LOG_ERROR,

  1372.                        "ERROR : no subband found for frequency %d\n", k);

  1373.                 return -1;

  1374.             }

  1375. 

  1376.             alpha[0] = alpha1[p][0] * bw_array[g] * bw_array[g];

  1377.             alpha[1] = alpha1[p][1] * bw_array[g] * bw_array[g];

  1378.             alpha[2] = alpha0[p][0] * bw_array[g];

  1379.             alpha[3] = alpha0[p][1] * bw_array[g];

  1380. 

  1381.             for (i = 2 * t_env[0]; i < 2 * t_env[bs_num_env]; i++) {

  1382.                 const int idx = i + ENVELOPE_ADJUSTMENT_OFFSET;

  1383.                 X_high[k][idx][0] =

  1384.                     X_low[p][idx - 2][0] * alpha[0] -

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

  1386.                     X_low[p][idx - 1][0] * alpha[2] -

  1387.                     X_low[p][idx - 1][1] * alpha[3] +

  1388.                     X_low[p][idx][0];

  1389.                 X_high[k][idx][1] =

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

  1391.                     X_low[p][idx - 2][0] * alpha[1] +

  1392.                     X_low[p][idx - 1][1] * alpha[2] +

  1393.                     X_low[p][idx - 1][0] * alpha[3] +

  1394.                     X_low[p][idx][1];

  1395.             }

  1396.         }

  1397.     }

  1398.     if (k < sbr->m[1] + sbr->kx[1])

  1399.         memset(X_high + k, 0, (sbr->m[1] + sbr->kx[1] - k) * sizeof(*X_high));

  1400. 

  1401.     return 0;

  1402. }

  1403. 

  1404. /// Generate the subband filtered lowband

  1405. static int sbr_x_gen(SpectralBandReplication *sbr, float X[2][32][64],

  1406.                      const float X_low[32][40][2], const float Y[2][38][64][2],

  1407.                      int ch)

  1408. {

  1409.     int k, i;

  1410.     const int i_f = 32;

  1411.     const int i_Temp = FFMAX(2*sbr->data[ch].t_env_num_env_old - i_f, 0);

  1412.     memset(X, 0, 2*sizeof(*X));

  1413.     for (k = 0; k < sbr->kx[0]; k++) {

  1414.         for (i = 0; i < i_Temp; i++) {

  1415.             X[0][i][k] = X_low[k][i + ENVELOPE_ADJUSTMENT_OFFSET][0];

  1416.             X[1][i][k] = X_low[k][i + ENVELOPE_ADJUSTMENT_OFFSET][1];

  1417.         }

  1418.     }

  1419.     for (; k < sbr->kx[0] + sbr->m[0]; k++) {

  1420.         for (i = 0; i < i_Temp; i++) {

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

  1422.             X[1][i][k] = Y[0][i + i_f][k][1];

  1423.         }

  1424.     }

  1425. 

  1426.     for (k = 0; k < sbr->kx[1]; k++) {

  1427.         for (i = i_Temp; i < i_f; i++) {

  1428.             X[0][i][k] = X_low[k][i + ENVELOPE_ADJUSTMENT_OFFSET][0];

  1429.             X[1][i][k] = X_low[k][i + ENVELOPE_ADJUSTMENT_OFFSET][1];

  1430.         }

  1431.     }

  1432.     for (; k < sbr->kx[1] + sbr->m[1]; k++) {

  1433.         for (i = i_Temp; i < i_f; i++) {

  1434.             X[0][i][k] = Y[1][i][k][0];

  1435.             X[1][i][k] = Y[1][i][k][1];

  1436.         }

  1437.     }

  1438.     return 0;

  1439. }

  1440. 

  1441. /** High Frequency Adjustment (14496-3 sp04 p217) and Mapping

  1442.  * (14496-3 sp04 p217)

  1443.  */

  1444. static void sbr_mapping(AACContext *ac, SpectralBandReplication *sbr,

  1445.                         SBRData *ch_data, int e_a[2])

  1446. {

  1447.     int e, i, m;

  1448. 

  1449.     memset(ch_data->s_indexmapped[1], 0, 7*sizeof(ch_data->s_indexmapped[1]));

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

  1451.         const unsigned int ilim = sbr->n[ch_data->bs_freq_res[e + 1]];

  1452.         uint16_t *table = ch_data->bs_freq_res[e + 1] ? sbr->f_tablehigh : sbr->f_tablelow;

  1453.         int k;

  1454. 

  1455.         for (i = 0; i < ilim; i++)

  1456.             for (m = table[i]; m < table[i + 1]; m++)

  1457.                 sbr->e_origmapped[e][m - sbr->kx[1]] = ch_data->env_facs[e+1][i];

  1458. 

  1459.         // ch_data->bs_num_noise > 1 => 2 noise floors

  1460.         k = (ch_data->bs_num_noise > 1) && (ch_data->t_env[e] >= ch_data->t_q[1]);

  1461.         for (i = 0; i < sbr->n_q; i++)

  1462.             for (m = sbr->f_tablenoise[i]; m < sbr->f_tablenoise[i + 1]; m++)

  1463.                 sbr->q_mapped[e][m - sbr->kx[1]] = ch_data->noise_facs[k+1][i];

  1464. 

  1465.         for (i = 0; i < sbr->n[1]; i++) {

  1466.             if (ch_data->bs_add_harmonic_flag) {

  1467.                 const unsigned int m_midpoint =

  1468.                     (sbr->f_tablehigh[i] + sbr->f_tablehigh[i + 1]) >> 1;

  1469. 

  1470.                 ch_data->s_indexmapped[e + 1][m_midpoint - sbr->kx[1]] = ch_data->bs_add_harmonic[i] *

  1471.                     (e >= e_a[1] || (ch_data->s_indexmapped[0][m_midpoint - sbr->kx[1]] == 1));

  1472.             }

  1473.         }

  1474. 

  1475.         for (i = 0; i < ilim; i++) {

  1476.             int additional_sinusoid_present = 0;

  1477.             for (m = table[i]; m < table[i + 1]; m++) {

  1478.                 if (ch_data->s_indexmapped[e + 1][m - sbr->kx[1]]) {

  1479.                     additional_sinusoid_present = 1;

  1480.                     break;

  1481.                 }

  1482.             }

  1483.             memset(&sbr->s_mapped[e][table[i] - sbr->kx[1]], additional_sinusoid_present,

  1484.                    (table[i + 1] - table[i]) * sizeof(sbr->s_mapped[e][0]));

  1485.         }

  1486.     }

  1487. 

  1488.     memcpy(ch_data->s_indexmapped[0], ch_data->s_indexmapped[ch_data->bs_num_env], sizeof(ch_data->s_indexmapped[0]));

  1489. }

  1490. 

  1491. /// Estimation of current envelope (14496-3 sp04 p218)

  1492. static void sbr_env_estimate(float (*e_curr)[48], float X_high[64][40][2],

  1493.                              SpectralBandReplication *sbr, SBRData *ch_data)

  1494. {

  1495.     int e, i, m;

  1496. 

  1497.     if (sbr->bs_interpol_freq) {

  1498.         for (e = 0; e < ch_data->bs_num_env; e++) {

  1499.             const float recip_env_size = 0.5f / (ch_data->t_env[e + 1] - ch_data->t_env[e]);

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

  1501.             int iub = ch_data->t_env[e + 1] * 2 + ENVELOPE_ADJUSTMENT_OFFSET;

  1502. 

  1503.             for (m = 0; m < sbr->m[1]; m++) {

  1504.                 float sum = 0.0f;

  1505. 

  1506.                 for (i = ilb; i < iub; i++) {

  1507.                     sum += X_high[m + sbr->kx[1]][i][0] * X_high[m + sbr->kx[1]][i][0] +

  1508.                            X_high[m + sbr->kx[1]][i][1] * X_high[m + sbr->kx[1]][i][1];

  1509.                 }

  1510.                 e_curr[e][m] = sum * recip_env_size;

  1511.             }

  1512.         }

  1513.     } else {

  1514.         int k, p;

  1515. 

  1516.         for (e = 0; e < ch_data->bs_num_env; e++) {

  1517.             const int env_size = 2 * (ch_data->t_env[e + 1] - ch_data->t_env[e]);

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

  1519.             int iub = ch_data->t_env[e + 1] * 2 + ENVELOPE_ADJUSTMENT_OFFSET;

  1520.             const uint16_t *table = ch_data->bs_freq_res[e + 1] ? sbr->f_tablehigh : sbr->f_tablelow;

  1521. 

  1522.             for (p = 0; p < sbr->n[ch_data->bs_freq_res[e + 1]]; p++) {

  1523.                 float sum = 0.0f;

  1524.                 const int den = env_size * (table[p + 1] - table[p]);

  1525. 

  1526.                 for (k = table[p]; k < table[p + 1]; k++) {

  1527.                     for (i = ilb; i < iub; i++) {

  1528.                         sum += X_high[k][i][0] * X_high[k][i][0] +

  1529.                                X_high[k][i][1] * X_high[k][i][1];

  1530.                     }

  1531.                 }

  1532.                 sum /= den;

  1533.                 for (k = table[p]; k < table[p + 1]; k++) {

  1534.                     e_curr[e][k - sbr->kx[1]] = sum;

  1535.                 }

  1536.             }

  1537.         }

  1538.     }

  1539. }

  1540. 

  1541. /**

  1542.  * Calculation of levels of additional HF signal components (14496-3 sp04 p219)

  1543.  * and Calculation of gain (14496-3 sp04 p219)

  1544.  */

  1545. static void sbr_gain_calc(AACContext *ac, SpectralBandReplication *sbr,

  1546.                           SBRData *ch_data, const int e_a[2])

  1547. {

  1548.     int e, k, m;

  1549.     // max gain limits : -3dB, 0dB, 3dB, inf dB (limiter off)

  1550.     static const float limgain[4] = { 0.70795, 1.0, 1.41254, 10000000000 };

  1551. 

  1552.     for (e = 0; e < ch_data->bs_num_env; e++) {

  1553.         int delta = !((e == e_a[1]) || (e == e_a[0]));

  1554.         for (k = 0; k < sbr->n_lim; k++) {

  1555.             float gain_boost, gain_max;

  1556.             float sum[2] = { 0.0f, 0.0f };

  1557.             for (m = sbr->f_tablelim[k] - sbr->kx[1]; m < sbr->f_tablelim[k + 1] - sbr->kx[1]; m++) {

  1558.                 const float temp = sbr->e_origmapped[e][m] / (1.0f + sbr->q_mapped[e][m]);

  1559.                 sbr->q_m[e][m] = sqrtf(temp * sbr->q_mapped[e][m]);

  1560.                 sbr->s_m[e][m] = sqrtf(temp * ch_data->s_indexmapped[e + 1][m]);

  1561.                 if (!sbr->s_mapped[e][m]) {

  1562.                     sbr->gain[e][m] = sqrtf(sbr->e_origmapped[e][m] /

  1563.                                             ((1.0f + sbr->e_curr[e][m]) *

  1564.                                              (1.0f + sbr->q_mapped[e][m] * delta)));

  1565.                 } else {

  1566.                     sbr->gain[e][m] = sqrtf(sbr->e_origmapped[e][m] * sbr->q_mapped[e][m] /

  1567.                                             ((1.0f + sbr->e_curr[e][m]) *

  1568.                                              (1.0f + sbr->q_mapped[e][m])));

  1569.                 }

  1570.             }

  1571.             for (m = sbr->f_tablelim[k] - sbr->kx[1]; m < sbr->f_tablelim[k + 1] - sbr->kx[1]; m++) {

  1572.                 sum[0] += sbr->e_origmapped[e][m];

  1573.                 sum[1] += sbr->e_curr[e][m];

  1574.             }

  1575.             gain_max = limgain[sbr->bs_limiter_gains] * sqrtf((FLT_EPSILON + sum[0]) / (FLT_EPSILON + sum[1]));

  1576.             gain_max = FFMIN(100000, gain_max);

  1577.             for (m = sbr->f_tablelim[k] - sbr->kx[1]; m < sbr->f_tablelim[k + 1] - sbr->kx[1]; m++) {

  1578.                 float q_m_max   = sbr->q_m[e][m] * gain_max / sbr->gain[e][m];

  1579.                 sbr->q_m[e][m]  = FFMIN(sbr->q_m[e][m], q_m_max);

  1580.                 sbr->gain[e][m] = FFMIN(sbr->gain[e][m], gain_max);

  1581.             }

  1582.             sum[0] = sum[1] = 0.0f;

  1583.             for (m = sbr->f_tablelim[k] - sbr->kx[1]; m < sbr->f_tablelim[k + 1] - sbr->kx[1]; m++) {

  1584.                 sum[0] += sbr->e_origmapped[e][m];

  1585.                 sum[1] += sbr->e_curr[e][m] * sbr->gain[e][m] * sbr->gain[e][m]

  1586.                           + sbr->s_m[e][m] * sbr->s_m[e][m]

  1587.                           + (delta && !sbr->s_m[e][m]) * sbr->q_m[e][m] * sbr->q_m[e][m];

  1588.             }

  1589.             gain_boost = sqrtf((FLT_EPSILON + sum[0]) / (FLT_EPSILON + sum[1]));

  1590.             gain_boost = FFMIN(1.584893192, gain_boost);

  1591.             for (m = sbr->f_tablelim[k] - sbr->kx[1]; m < sbr->f_tablelim[k + 1] - sbr->kx[1]; m++) {

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

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

  1594.                 sbr->s_m[e][m]  *= gain_boost;

  1595.             }

  1596.         }

  1597.     }

  1598. }

  1599. 

  1600. /// Assembling HF Signals (14496-3 sp04 p220)

  1601. static void sbr_hf_assemble(float Y[2][38][64][2], const float X_high[64][40][2],

  1602.                             SpectralBandReplication *sbr, SBRData *ch_data,

  1603.                             const int e_a[2])

  1604. {

  1605.     int e, i, j, m;

  1606.     const int h_SL = 4 * !sbr->bs_smoothing_mode;

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

  1608.     const int m_max = sbr->m[1];

  1609.     static const float h_smooth[5] = {

  1610.         0.33333333333333,

  1611.         0.30150283239582,

  1612.         0.21816949906249,

  1613.         0.11516383427084,

  1614.         0.03183050093751,

  1615.     };

  1616.     static const int8_t phi[2][4] = {

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

  1618.         {  0,  1,  0, -1}, // imaginary

  1619.     };

  1620.     float (*g_temp)[48] = ch_data->g_temp, (*q_temp)[48] = ch_data->q_temp;

  1621.     int indexnoise = ch_data->f_indexnoise;

  1622.     int indexsine  = ch_data->f_indexsine;

  1623.     memcpy(Y[0], Y[1], sizeof(Y[0]));

  1624. 

  1625.     if (sbr->reset) {

  1626.         for (i = 0; i < h_SL; i++) {

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

  1628.             memcpy(q_temp[i + 2*ch_data->t_env[0]], sbr->q_m[0],  m_max * sizeof(sbr->q_m[0][0]));

  1629.         }

  1630.     } else if (h_SL) {

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

  1632.         memcpy(q_temp[2*ch_data->t_env[0]], q_temp[2*ch_data->t_env_num_env_old], 4*sizeof(q_temp[0]));

  1633.     }

  1634. 

  1635.     for (e = 0; e < ch_data->bs_num_env; e++) {

  1636.         for (i = 2 * ch_data->t_env[e]; i < 2 * ch_data->t_env[e + 1]; i++) {

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

  1638.             memcpy(q_temp[h_SL + i], sbr->q_m[e],  m_max * sizeof(sbr->q_m[0][0]));

  1639.         }

  1640.     }

  1641. 

  1642.     for (e = 0; e < ch_data->bs_num_env; e++) {

  1643.         for (i = 2 * ch_data->t_env[e]; i < 2 * ch_data->t_env[e + 1]; i++) {

  1644.             int phi_sign = (1 - 2*(kx & 1));

  1645. 

  1646.             if (h_SL && e != e_a[0] && e != e_a[1]) {

  1647.                 for (m = 0; m < m_max; m++) {

  1648.                     const int idx1 = i + h_SL;

  1649.                     float g_filt = 0.0f;

  1650.                     for (j = 0; j <= h_SL; j++)

  1651.                         g_filt += g_temp[idx1 - j][m] * h_smooth[j];

  1652.                     Y[1][i][m + kx][0] =

  1653.                         X_high[m + kx][i + ENVELOPE_ADJUSTMENT_OFFSET][0] * g_filt;

  1654.                     Y[1][i][m + kx][1] =

  1655.                         X_high[m + kx][i + ENVELOPE_ADJUSTMENT_OFFSET][1] * g_filt;

  1656.                 }

  1657.             } else {

  1658.                 for (m = 0; m < m_max; m++) {

  1659.                     const float g_filt = g_temp[i + h_SL][m];

  1660.                     Y[1][i][m + kx][0] =

  1661.                         X_high[m + kx][i + ENVELOPE_ADJUSTMENT_OFFSET][0] * g_filt;

  1662.                     Y[1][i][m + kx][1] =

  1663.                         X_high[m + kx][i + ENVELOPE_ADJUSTMENT_OFFSET][1] * g_filt;

  1664.                 }

  1665.             }

  1666. 

  1667.             if (e != e_a[0] && e != e_a[1]) {

  1668.                 for (m = 0; m < m_max; m++) {

  1669.                     indexnoise = (indexnoise + 1) & 0x1ff;

  1670.                     if (sbr->s_m[e][m]) {

  1671.                         Y[1][i][m + kx][0] +=

  1672.                             sbr->s_m[e][m] * phi[0][indexsine];

  1673.                         Y[1][i][m + kx][1] +=

  1674.                             sbr->s_m[e][m] * (phi[1][indexsine] * phi_sign);

  1675.                     } else {

  1676.                         float q_filt;

  1677.                         if (h_SL) {

  1678.                             const int idx1 = i + h_SL;

  1679.                             q_filt = 0.0f;

  1680.                             for (j = 0; j <= h_SL; j++)

  1681.                                 q_filt += q_temp[idx1 - j][m] * h_smooth[j];

  1682.                         } else {

  1683.                             q_filt = q_temp[i][m];

  1684.                         }

  1685.                         Y[1][i][m + kx][0] +=

  1686.                             q_filt * sbr_noise_table[indexnoise][0];

  1687.                         Y[1][i][m + kx][1] +=

  1688.                             q_filt * sbr_noise_table[indexnoise][1];

  1689.                     }

  1690.                     phi_sign = -phi_sign;

  1691.                 }

  1692.             } else {

  1693.                 indexnoise = (indexnoise + m_max) & 0x1ff;

  1694.                 for (m = 0; m < m_max; m++) {

  1695.                     Y[1][i][m + kx][0] +=

  1696.                         sbr->s_m[e][m] * phi[0][indexsine];

  1697.                     Y[1][i][m + kx][1] +=

  1698.                         sbr->s_m[e][m] * (phi[1][indexsine] * phi_sign);

  1699.                     phi_sign = -phi_sign;

  1700.                 }

  1701.             }

  1702.             indexsine = (indexsine + 1) & 3;

  1703.         }

  1704.     }

  1705.     ch_data->f_indexnoise = indexnoise;

  1706.     ch_data->f_indexsine  = indexsine;

  1707. }

  1708. 

  1709. void ff_sbr_apply(AACContext *ac, SpectralBandReplication *sbr, int id_aac,

  1710.                   float* L, float* R)

  1711. {

  1712.     int downsampled = ac->m4ac.ext_sample_rate < sbr->sample_rate;

  1713.     int ch;

  1714.     int nch = (id_aac == TYPE_CPE) ? 2 : 1;

  1715. 

  1716.     if (sbr->start) {

  1717.         sbr_dequant(sbr, id_aac);

  1718.     }

  1719.     for (ch = 0; ch < nch; ch++) {

  1720.         /* decode channel */

  1721.         sbr_qmf_analysis(&ac->dsp, &sbr->mdct_ana, ch ? R : L, sbr->data[ch].analysis_filterbank_samples,

  1722.                          (float*)sbr->qmf_filter_scratch,

  1723.                          sbr->data[ch].W, 1/(-1024 * ac->sf_scale));

  1724.         sbr_lf_gen(ac, sbr, sbr->X_low, sbr->data[ch].W);

  1725.         if (sbr->start) {

  1726.             sbr_hf_inverse_filter(sbr->alpha0, sbr->alpha1, sbr->X_low, sbr->k[0]);

  1727.             sbr_chirp(sbr, &sbr->data[ch]);

  1728.             sbr_hf_gen(ac, sbr, sbr->X_high, sbr->X_low, sbr->alpha0, sbr->alpha1,

  1729.                        sbr->data[ch].bw_array, sbr->data[ch].t_env,

  1730.                        sbr->data[ch].bs_num_env);

  1731. 

  1732.             // hf_adj

  1733.             sbr_mapping(ac, sbr, &sbr->data[ch], sbr->data[ch].e_a);

  1734.             sbr_env_estimate(sbr->e_curr, sbr->X_high, sbr, &sbr->data[ch]);

  1735.             sbr_gain_calc(ac, sbr, &sbr->data[ch], sbr->data[ch].e_a);

  1736.             sbr_hf_assemble(sbr->data[ch].Y, sbr->X_high, sbr, &sbr->data[ch],

  1737.                             sbr->data[ch].e_a);

  1738.         }

  1739. 

  1740.         /* synthesis */

  1741.         sbr_x_gen(sbr, sbr->X[ch], sbr->X_low, sbr->data[ch].Y, ch);

  1742.     }

  1743.     sbr_qmf_synthesis(&ac->dsp, &sbr->mdct, L, sbr->X[0], sbr->qmf_filter_scratch,

  1744.                       sbr->data[0].synthesis_filterbank_samples,

  1745.                       &sbr->data[0].synthesis_filterbank_samples_offset,

  1746.                       downsampled,

  1747.                       ac->add_bias, -1024 * ac->sf_scale);

  1748.     if (nch == 2)

  1749.         sbr_qmf_synthesis(&ac->dsp, &sbr->mdct, R, sbr->X[1], sbr->qmf_filter_scratch,

  1750.                           sbr->data[1].synthesis_filterbank_samples,

  1751.                           &sbr->data[1].synthesis_filterbank_samples_offset,

  1752.                           downsampled,

  1753.                           ac->add_bias, -1024 * ac->sf_scale);

  1754. }