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FFmpeg/libavcodec/aacsbr.c

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  1. /*

  2.  * AAC Spectral Band Replication decoding functions

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

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

  5.  *

  6.  * This file is part of Libav.

  7.  *

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

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

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

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

  12.  *

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

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

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

  16.  * Lesser General Public License for more details.

  17.  *

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

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

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

  21.  */

  22. 

  23. /**

  24.  * @file

  25.  * AAC Spectral Band Replication decoding functions

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

  27.  */

  28. 

  29. #include "aac.h"

  30. #include "sbr.h"

  31. #include "aacsbr.h"

  32. #include "aacsbrdata.h"

  33. #include "fft.h"

  34. #include "aacps.h"

  35. #include "libavutil/libm.h"

  36. 

  37. #include <stdint.h>

  38. #include <float.h>

  39. 

  40. #define ENVELOPE_ADJUSTMENT_OFFSET 2

  41. #define NOISE_FLOOR_OFFSET 6.0f

  42. 

  43. /**

  44.  * SBR VLC tables

  45.  */

  46. enum {

  47.     T_HUFFMAN_ENV_1_5DB,

  48.     F_HUFFMAN_ENV_1_5DB,

  49.     T_HUFFMAN_ENV_BAL_1_5DB,

  50.     F_HUFFMAN_ENV_BAL_1_5DB,

  51.     T_HUFFMAN_ENV_3_0DB,

  52.     F_HUFFMAN_ENV_3_0DB,

  53.     T_HUFFMAN_ENV_BAL_3_0DB,

  54.     F_HUFFMAN_ENV_BAL_3_0DB,

  55.     T_HUFFMAN_NOISE_3_0DB,

  56.     T_HUFFMAN_NOISE_BAL_3_0DB,

  57. };

  58. 

  59. /**

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

  61.  */

  62. enum {

  63.     FIXFIX,

  64.     FIXVAR,

  65.     VARFIX,

  66.     VARVAR,

  67. };

  68. 

  69. enum {

  70.     EXTENSION_ID_PS = 2,

  71. };

  72. 

  73. static VLC vlc_sbr[10];

  74. static const int8_t vlc_sbr_lav[10] =

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

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

  77. 

  78. #define SBR_INIT_VLC_STATIC(num, size) \

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

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

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

  82.                     size)

  83. 

  84. #define SBR_VLC_ROW(name) \

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

  86. 

  87. av_cold void ff_aac_sbr_init(void)

  88. {

  89.     int n;

  90.     static const struct {

  91.         const void *sbr_codes, *sbr_bits;

  92.         const unsigned int table_size, elem_size;

  93.     } sbr_tmp[] = {

  94.         SBR_VLC_ROW(t_huffman_env_1_5dB),

  95.         SBR_VLC_ROW(f_huffman_env_1_5dB),

  96.         SBR_VLC_ROW(t_huffman_env_bal_1_5dB),

  97.         SBR_VLC_ROW(f_huffman_env_bal_1_5dB),

  98.         SBR_VLC_ROW(t_huffman_env_3_0dB),

  99.         SBR_VLC_ROW(f_huffman_env_3_0dB),

  100.         SBR_VLC_ROW(t_huffman_env_bal_3_0dB),

  101.         SBR_VLC_ROW(f_huffman_env_bal_3_0dB),

  102.         SBR_VLC_ROW(t_huffman_noise_3_0dB),

  103.         SBR_VLC_ROW(t_huffman_noise_bal_3_0dB),

  104.     };

  105. 

  106.     // SBR VLC table initialization

  107.     SBR_INIT_VLC_STATIC(0, 1098);

  108.     SBR_INIT_VLC_STATIC(1, 1092);

  109.     SBR_INIT_VLC_STATIC(2, 768);

  110.     SBR_INIT_VLC_STATIC(3, 1026);

  111.     SBR_INIT_VLC_STATIC(4, 1058);

  112.     SBR_INIT_VLC_STATIC(5, 1052);

  113.     SBR_INIT_VLC_STATIC(6, 544);

  114.     SBR_INIT_VLC_STATIC(7, 544);

  115.     SBR_INIT_VLC_STATIC(8, 592);

  116.     SBR_INIT_VLC_STATIC(9, 512);

  117. 

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

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

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

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

  122. 

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

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

  125. 

  126.     ff_ps_init();

  127. }

  128. 

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

  130. {

  131.     float mdct_scale;

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

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

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

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

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

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

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

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

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

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

  142.     ff_ps_ctx_init(&sbr->ps);

  143. }

  144. 

  145. av_cold void ff_aac_sbr_ctx_close(SpectralBandReplication *sbr)

  146. {

  147.     ff_mdct_end(&sbr->mdct);

  148.     ff_mdct_end(&sbr->mdct_ana);

  149. }

  150. 

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

  152. {

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

  154. }

  155. 

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

  157. {

  158.     int i;

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

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

  161.             return 1;

  162.     return 0;

  163. }

  164. 

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

  166. static void sbr_make_f_tablelim(SpectralBandReplication *sbr)

  167. {

  168.     int k;

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

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

  171.                                                1.18509277094158210129f,   //2^(0.49/2)

  172.                                                1.11987160404675912501f }; //2^(0.49/3)

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

  174.         int16_t patch_borders[7];

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

  176. 

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

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

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

  180. 

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

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

  183.         if (sbr->num_patches > 1)

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

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

  186. 

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

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

  189.               qsort_comparison_function_int16);

  190. 

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

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

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

  194.                 *++out = *in++;

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

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

  197.                 in++;

  198.                 sbr->n_lim--;

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

  200.                 *out = *in++;

  201.                 sbr->n_lim--;

  202.             } else {

  203.                 *++out = *in++;

  204.             }

  205.         }

  206.     } else {

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

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

  209.         sbr->n_lim = 1;

  210.     }

  211. }

  212. 

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

  214. {

  215.     unsigned int cnt = get_bits_count(gb);

  216.     uint8_t bs_header_extra_1;

  217.     uint8_t bs_header_extra_2;

  218.     int old_bs_limiter_bands = sbr->bs_limiter_bands;

  219.     SpectrumParameters old_spectrum_params;

  220. 

  221.     sbr->start = 1;

  222. 

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

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

  225. 

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

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

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

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

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

  231. 

  232.     bs_header_extra_1 = get_bits1(gb);

  233.     bs_header_extra_2 = get_bits1(gb);

  234. 

  235.     if (bs_header_extra_1) {

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

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

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

  239.     } else {

  240.         sbr->spectrum_params.bs_freq_scale  = 2;

  241.         sbr->spectrum_params.bs_alter_scale = 1;

  242.         sbr->spectrum_params.bs_noise_bands = 2;

  243.     }

  244. 

  245.     // Check if spectrum parameters changed

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

  247.         sbr->reset = 1;

  248. 

  249.     if (bs_header_extra_2) {

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

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

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

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

  254.     } else {

  255.         sbr->bs_limiter_bands  = 2;

  256.         sbr->bs_limiter_gains  = 2;

  257.         sbr->bs_interpol_freq  = 1;

  258.         sbr->bs_smoothing_mode = 1;

  259.     }

  260. 

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

  262.         sbr_make_f_tablelim(sbr);

  263. 

  264.     return get_bits_count(gb) - cnt;

  265. }

  266. 

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

  268. {

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

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

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

  272.     return min;

  273. }

  274. 

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

  276. {

  277.     int k, previous, present;

  278.     float base, prod;

  279. 

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

  281.     prod = start;

  282.     previous = start;

  283. 

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

  285.         prod *= base;

  286.         present  = lrintf(prod);

  287.         bands[k] = present - previous;

  288.         previous = present;

  289.     }

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

  291. }

  292. 

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

  294. {

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

  296.     if (n_master <= 0) {

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

  298.         return -1;

  299.     }

  300.     if (bs_xover_band >= n_master) {

  301.         av_log(avctx, AV_LOG_ERROR,

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

  303.                bs_xover_band);

  304.         return -1;

  305.     }

  306.     return 0;

  307. }

  308. 

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

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

  311.                              SpectrumParameters *spectrum)

  312. {

  313.     unsigned int temp, max_qmf_subbands;

  314.     unsigned int start_min, stop_min;

  315.     int k;

  316.     const int8_t *sbr_offset_ptr;

  317.     int16_t stop_dk[13];

  318. 

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

  320.         temp = 3000;

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

  322.         temp = 4000;

  323.     } else

  324.         temp = 5000;

  325. 

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

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

  328. 

  329.     switch (sbr->sample_rate) {

  330.     case 16000:

  331.         sbr_offset_ptr = sbr_offset[0];

  332.         break;

  333.     case 22050:

  334.         sbr_offset_ptr = sbr_offset[1];

  335.         break;

  336.     case 24000:

  337.         sbr_offset_ptr = sbr_offset[2];

  338.         break;

  339.     case 32000:

  340.         sbr_offset_ptr = sbr_offset[3];

  341.         break;

  342.     case 44100: case 48000: case 64000:

  343.         sbr_offset_ptr = sbr_offset[4];

  344.         break;

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

  346.         sbr_offset_ptr = sbr_offset[5];

  347.         break;

  348.     default:

  349.         av_log(ac->avctx, AV_LOG_ERROR,

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

  351.         return -1;

  352.     }

  353. 

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

  355. 

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

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

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

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

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

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

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

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

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

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

  366.     } else {

  367.         av_log(ac->avctx, AV_LOG_ERROR,

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

  369.         return -1;

  370.     }

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

  372. 

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

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

  375.         max_qmf_subbands = 48;

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

  377.         max_qmf_subbands = 35;

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

  379.         max_qmf_subbands = 32;

  380. 

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

  382.         av_log(ac->avctx, AV_LOG_ERROR,

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

  384.         return -1;

  385.     }

  386. 

  387.     if (!spectrum->bs_freq_scale) {

  388.         int dk, k2diff;

  389. 

  390.         dk = spectrum->bs_alter_scale + 1;

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

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

  393.             return -1;

  394. 

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

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

  397. 

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

  399.         if (k2diff < 0) {

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

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

  402.         } else if (k2diff) {

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

  404.         }

  405. 

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

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

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

  409. 

  410.     } else {

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

  412.         int two_regions, num_bands_0;

  413.         int vdk0_max, vdk1_min;

  414.         int16_t vk0[49];

  415. 

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

  417.             two_regions = 1;

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

  419.         } else {

  420.             two_regions = 0;

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

  422.         }

  423. 

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

  425. 

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

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

  428.             return -1;

  429.         }

  430. 

  431.         vk0[0] = 0;

  432. 

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

  434. 

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

  436.         vdk0_max = vk0[num_bands_0];

  437. 

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

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

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

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

  442.                 return -1;

  443.             }

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

  445.         }

  446. 

  447.         if (two_regions) {

  448.             int16_t vk1[49];

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

  450.                                                      : 1.0f; // bs_alter_scale = {0,1}

  451.             int num_bands_1 = lrintf(half_bands * invwarp *

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

  453. 

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

  455. 

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

  457. 

  458.             if (vdk1_min < vdk0_max) {

  459.                 int change;

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

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

  462.                 vk1[1]           += change;

  463.                 vk1[num_bands_1] -= change;

  464.             }

  465. 

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

  467. 

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

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

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

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

  472.                     return -1;

  473.                 }

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

  475.             }

  476. 

  477.             sbr->n_master = num_bands_0 + num_bands_1;

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

  479.                 return -1;

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

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

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

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

  484. 

  485.         } else {

  486.             sbr->n_master = num_bands_0;

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

  488.                 return -1;

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

  490.         }

  491.     }

  492. 

  493.     return 0;

  494. }

  495. 

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

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

  498. {

  499.     int i, k, sb = 0;

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

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

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

  503. 

  504.     sbr->num_patches = 0;

  505. 

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

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

  508.     } else

  509.         k = sbr->n_master;

  510. 

  511.     do {

  512.         int odd = 0;

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

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

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

  516.         }

  517. 

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

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

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

  521.         // count of 6 patches

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

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

  524.             return -1;

  525.         }

  526. 

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

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

  529. 

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

  531.             usb = sb;

  532.             msb = sb;

  533.             sbr->num_patches++;

  534.         } else

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

  536. 

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

  538.             k = sbr->n_master;

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

  540. 

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

  542.         sbr->num_patches--;

  543. 

  544.     return 0;

  545. }

  546. 

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

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

  549. {

  550.     int k, temp;

  551. 

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

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

  554. 

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

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

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

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

  559. 

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

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

  562.         av_log(ac->avctx, AV_LOG_ERROR,

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

  564.         return -1;

  565.     }

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

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

  568.         return -1;

  569.     }

  570. 

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

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

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

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

  575. 

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

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

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

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

  580.         return -1;

  581.     }

  582. 

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

  584.     temp = 0;

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

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

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

  588.     }

  589. 

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

  591.         return -1;

  592. 

  593.     sbr_make_f_tablelim(sbr);

  594. 

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

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

  597. 

  598.     return 0;

  599. }

  600. 

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

  602.                                               int elements)

  603. {

  604.     int i;

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

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

  607.     }

  608. }

  609. 

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

  611. static const int8_t ceil_log2[] = {

  612.     0, 1, 2, 2, 3, 3,

  613. };

  614. 

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

  616.                          GetBitContext *gb, SBRData *ch_data)

  617. {

  618.     int i;

  619.     unsigned bs_pointer = 0;

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

  621.     int abs_bord_trail = 16;

  622.     int num_rel_lead, num_rel_trail;

  623.     unsigned bs_num_env_old = ch_data->bs_num_env;

  624. 

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

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

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

  628. 

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

  630.     case FIXFIX:

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

  632.         num_rel_lead                        = ch_data->bs_num_env - 1;

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

  634.             ch_data->bs_amp_res = 0;

  635. 

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

  637.             av_log(ac->avctx, AV_LOG_ERROR,

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

  639.                    ch_data->bs_num_env);

  640.             return -1;

  641.         }

  642. 

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

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

  645. 

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

  647.                    ch_data->bs_num_env;

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

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

  650. 

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

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

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

  654.         break;

  655.     case FIXVAR:

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

  657.         num_rel_trail                       = get_bits(gb, 2);

  658.         ch_data->bs_num_env                 = num_rel_trail + 1;

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

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

  661. 

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

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

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

  665. 

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

  667. 

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

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

  670.         break;

  671.     case VARFIX:

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

  673.         num_rel_lead                        = get_bits(gb, 2);

  674.         ch_data->bs_num_env                 = num_rel_lead + 1;

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

  676. 

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

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

  679. 

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

  681. 

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

  683.         break;

  684.     case VARVAR:

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

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

  687.         num_rel_lead                        = get_bits(gb, 2);

  688.         num_rel_trail                       = get_bits(gb, 2);

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

  690. 

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

  692.             av_log(ac->avctx, AV_LOG_ERROR,

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

  694.                    ch_data->bs_num_env);

  695.             return -1;

  696.         }

  697. 

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

  699. 

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

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

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

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

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

  705. 

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

  707. 

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

  709.         break;

  710.     }

  711. 

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

  713.         av_log(ac->avctx, AV_LOG_ERROR,

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

  715.                bs_pointer);

  716.         return -1;

  717.     }

  718. 

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

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

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

  722.             return -1;

  723.         }

  724.     }

  725. 

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

  727. 

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

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

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

  731.         unsigned int idx;

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

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

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

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

  736.         } else { // VARFIX

  737.             if (!bs_pointer)

  738.                 idx = 1;

  739.             else if (bs_pointer == 1)

  740.                 idx = ch_data->bs_num_env - 1;

  741.             else // bs_pointer > 1

  742.                 idx = bs_pointer - 1;

  743.         }

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

  745.     }

  746. 

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

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

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

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

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

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

  753. 

  754.     return 0;

  755. }

  756. 

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

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

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

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

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

  762. 

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

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

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

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

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

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

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

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

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

  772. }

  773. 

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

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

  776.                           SBRData *ch_data)

  777. {

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

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

  780. }

  781. 

  782. /// Read inverse filtering data

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

  784.                           SBRData *ch_data)

  785. {

  786.     int i;

  787. 

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

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

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

  791. }

  792. 

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

  794.                               SBRData *ch_data, int ch)

  795. {

  796.     int bits;

  797.     int i, j, k;

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

  799.     int t_lav, f_lav;

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

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

  802. 

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

  804.         if (ch_data->bs_amp_res) {

  805.             bits   = 5;

  806.             t_huff = vlc_sbr[T_HUFFMAN_ENV_BAL_3_0DB].table;

  807.             t_lav  = vlc_sbr_lav[T_HUFFMAN_ENV_BAL_3_0DB];

  808.             f_huff = vlc_sbr[F_HUFFMAN_ENV_BAL_3_0DB].table;

  809.             f_lav  = vlc_sbr_lav[F_HUFFMAN_ENV_BAL_3_0DB];

  810.         } else {

  811.             bits   = 6;

  812.             t_huff = vlc_sbr[T_HUFFMAN_ENV_BAL_1_5DB].table;

  813.             t_lav  = vlc_sbr_lav[T_HUFFMAN_ENV_BAL_1_5DB];

  814.             f_huff = vlc_sbr[F_HUFFMAN_ENV_BAL_1_5DB].table;

  815.             f_lav  = vlc_sbr_lav[F_HUFFMAN_ENV_BAL_1_5DB];

  816.         }

  817.     } else {

  818.         if (ch_data->bs_amp_res) {

  819.             bits   = 6;

  820.             t_huff = vlc_sbr[T_HUFFMAN_ENV_3_0DB].table;

  821.             t_lav  = vlc_sbr_lav[T_HUFFMAN_ENV_3_0DB];

  822.             f_huff = vlc_sbr[F_HUFFMAN_ENV_3_0DB].table;

  823.             f_lav  = vlc_sbr_lav[F_HUFFMAN_ENV_3_0DB];

  824.         } else {

  825.             bits   = 7;

  826.             t_huff = vlc_sbr[T_HUFFMAN_ENV_1_5DB].table;

  827.             t_lav  = vlc_sbr_lav[T_HUFFMAN_ENV_1_5DB];

  828.             f_huff = vlc_sbr[F_HUFFMAN_ENV_1_5DB].table;

  829.             f_lav  = vlc_sbr_lav[F_HUFFMAN_ENV_1_5DB];

  830.         }

  831.     }

  832. 

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

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

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

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

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

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

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

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

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

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

  843.                 }

  844.             } else {

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

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

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

  848.                 }

  849.             }

  850.         } else {

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

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

  853.                 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);

  854.         }

  855.     }

  856. 

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

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

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

  860. }

  861. 

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

  863.                            SBRData *ch_data, int ch)

  864. {

  865.     int i, j;

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

  867.     int t_lav, f_lav;

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

  869. 

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

  871.         t_huff = vlc_sbr[T_HUFFMAN_NOISE_BAL_3_0DB].table;

  872.         t_lav  = vlc_sbr_lav[T_HUFFMAN_NOISE_BAL_3_0DB];

  873.         f_huff = vlc_sbr[F_HUFFMAN_ENV_BAL_3_0DB].table;

  874.         f_lav  = vlc_sbr_lav[F_HUFFMAN_ENV_BAL_3_0DB];

  875.     } else {

  876.         t_huff = vlc_sbr[T_HUFFMAN_NOISE_3_0DB].table;

  877.         t_lav  = vlc_sbr_lav[T_HUFFMAN_NOISE_3_0DB];

  878.         f_huff = vlc_sbr[F_HUFFMAN_ENV_3_0DB].table;

  879.         f_lav  = vlc_sbr_lav[F_HUFFMAN_ENV_3_0DB];

  880.     }

  881. 

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

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

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

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

  886.         } else {

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

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

  889.                 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);

  890.         }

  891.     }

  892. 

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

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

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

  896. }

  897. 

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

  899.                                GetBitContext *gb,

  900.                                int bs_extension_id, int *num_bits_left)

  901. {

  902.     switch (bs_extension_id) {

  903.     case EXTENSION_ID_PS:

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

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

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

  907.             *num_bits_left = 0;

  908.         } else {

  909. #if 1

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

  911. #else

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

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

  914.             *num_bits_left = 0;

  915. #endif

  916.         }

  917.         break;

  918.     default:

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

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

  921.         *num_bits_left = 0;

  922.         break;

  923.     }

  924. }

  925. 

  926. static int read_sbr_single_channel_element(AACContext *ac,

  927.                                             SpectralBandReplication *sbr,

  928.                                             GetBitContext *gb)

  929. {

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

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

  932. 

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

  934.         return -1;

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

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

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

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

  939. 

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

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

  942. 

  943.     return 0;

  944. }

  945. 

  946. static int read_sbr_channel_pair_element(AACContext *ac,

  947.                                           SpectralBandReplication *sbr,

  948.                                           GetBitContext *gb)

  949. {

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

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

  952. 

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

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

  955.             return -1;

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

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

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

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

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

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

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

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

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

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

  966.     } else {

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

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

  969.             return -1;

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

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

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

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

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

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

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

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

  978.     }

  979. 

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

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

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

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

  984. 

  985.     return 0;

  986. }

  987. 

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

  989.                                   GetBitContext *gb, int id_aac)

  990. {

  991.     unsigned int cnt = get_bits_count(gb);

  992. 

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

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

  995.             sbr->start = 0;

  996.             return get_bits_count(gb) - cnt;

  997.         }

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

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

  1000.             sbr->start = 0;

  1001.             return get_bits_count(gb) - cnt;

  1002.         }

  1003.     } else {

  1004.         av_log(ac->avctx, AV_LOG_ERROR,

  1005.             "Invalid bitstream - cannot apply SBR to element type %d\n", id_aac);

  1006.         sbr->start = 0;

  1007.         return get_bits_count(gb) - cnt;

  1008.     }

  1009.     if (get_bits1(gb)) { // bs_extended_data

  1010.         int num_bits_left = get_bits(gb, 4); // bs_extension_size

  1011.         if (num_bits_left == 15)

  1012.             num_bits_left += get_bits(gb, 8); // bs_esc_count

  1013. 

  1014.         num_bits_left <<= 3;

  1015.         while (num_bits_left > 7) {

  1016.             num_bits_left -= 2;

  1017.             read_sbr_extension(ac, sbr, gb, get_bits(gb, 2), &num_bits_left); // bs_extension_id

  1018.         }

  1019.         if (num_bits_left < 0) {

  1020.             av_log(ac->avctx, AV_LOG_ERROR, "SBR Extension over read.\n");

  1021.         }

  1022.         if (num_bits_left > 0)

  1023.             skip_bits(gb, num_bits_left);

  1024.     }

  1025. 

  1026.     return get_bits_count(gb) - cnt;

  1027. }

  1028. 

  1029. static void sbr_reset(AACContext *ac, SpectralBandReplication *sbr)

  1030. {

  1031.     int err;

  1032.     err = sbr_make_f_master(ac, sbr, &sbr->spectrum_params);

  1033.     if (err >= 0)

  1034.         err = sbr_make_f_derived(ac, sbr);

  1035.     if (err < 0) {

  1036.         av_log(ac->avctx, AV_LOG_ERROR,

  1037.                "SBR reset failed. Switching SBR to pure upsampling mode.\n");

  1038.         sbr->start = 0;

  1039.     }

  1040. }

  1041. 

  1042. /**

  1043.  * Decode Spectral Band Replication extension data; reference: table 4.55.

  1044.  *

  1045.  * @param   crc flag indicating the presence of CRC checksum

  1046.  * @param   cnt length of TYPE_FIL syntactic element in bytes

  1047.  *

  1048.  * @return  Returns number of bytes consumed from the TYPE_FIL element.

  1049.  */

  1050. int ff_decode_sbr_extension(AACContext *ac, SpectralBandReplication *sbr,

  1051.                             GetBitContext *gb_host, int crc, int cnt, int id_aac)

  1052. {

  1053.     unsigned int num_sbr_bits = 0, num_align_bits;

  1054.     unsigned bytes_read;

  1055.     GetBitContext gbc = *gb_host, *gb = &gbc;

  1056.     skip_bits_long(gb_host, cnt*8 - 4);

  1057. 

  1058.     sbr->reset = 0;

  1059. 

  1060.     if (!sbr->sample_rate)

  1061.         sbr->sample_rate = 2 * ac->m4ac.sample_rate; //TODO use the nominal sample rate for arbitrary sample rate support

  1062.     if (!ac->m4ac.ext_sample_rate)

  1063.         ac->m4ac.ext_sample_rate = 2 * ac->m4ac.sample_rate;

  1064. 

  1065.     if (crc) {

  1066.         skip_bits(gb, 10); // bs_sbr_crc_bits; TODO - implement CRC check

  1067.         num_sbr_bits += 10;

  1068.     }

  1069. 

  1070.     //Save some state from the previous frame.

  1071.     sbr->kx[0] = sbr->kx[1];

  1072.     sbr->m[0] = sbr->m[1];

  1073. 

  1074.     num_sbr_bits++;

  1075.     if (get_bits1(gb)) // bs_header_flag

  1076.         num_sbr_bits += read_sbr_header(sbr, gb);

  1077. 

  1078.     if (sbr->reset)

  1079.         sbr_reset(ac, sbr);

  1080. 

  1081.     if (sbr->start)

  1082.         num_sbr_bits  += read_sbr_data(ac, sbr, gb, id_aac);

  1083. 

  1084.     num_align_bits = ((cnt << 3) - 4 - num_sbr_bits) & 7;

  1085.     bytes_read = ((num_sbr_bits + num_align_bits + 4) >> 3);

  1086. 

  1087.     if (bytes_read > cnt) {

  1088.         av_log(ac->avctx, AV_LOG_ERROR,

  1089.                "Expected to read %d SBR bytes actually read %d.\n", cnt, bytes_read);

  1090.     }

  1091.     return cnt;

  1092. }

  1093. 

  1094. /// Dequantization and stereo decoding (14496-3 sp04 p203)

  1095. static void sbr_dequant(SpectralBandReplication *sbr, int id_aac)

  1096. {

  1097.     int k, e;

  1098.     int ch;

  1099. 

  1100.     if (id_aac == TYPE_CPE && sbr->bs_coupling) {

  1101.         float alpha      = sbr->data[0].bs_amp_res ?  1.0f :  0.5f;

  1102.         float pan_offset = sbr->data[0].bs_amp_res ? 12.0f : 24.0f;

  1103.         for (e = 1; e <= sbr->data[0].bs_num_env; e++) {

  1104.             for (k = 0; k < sbr->n[sbr->data[0].bs_freq_res[e]]; k++) {

  1105.                 float temp1 = exp2f(sbr->data[0].env_facs[e][k] * alpha + 7.0f);

  1106.                 float temp2 = exp2f((pan_offset - sbr->data[1].env_facs[e][k]) * alpha);

  1107.                 float fac   = temp1 / (1.0f + temp2);

  1108.                 sbr->data[0].env_facs[e][k] = fac;

  1109.                 sbr->data[1].env_facs[e][k] = fac * temp2;

  1110.             }

  1111.         }

  1112.         for (e = 1; e <= sbr->data[0].bs_num_noise; e++) {

  1113.             for (k = 0; k < sbr->n_q; k++) {

  1114.                 float temp1 = exp2f(NOISE_FLOOR_OFFSET - sbr->data[0].noise_facs[e][k] + 1);

  1115.                 float temp2 = exp2f(12 - sbr->data[1].noise_facs[e][k]);

  1116.                 float fac   = temp1 / (1.0f + temp2);

  1117.                 sbr->data[0].noise_facs[e][k] = fac;

  1118.                 sbr->data[1].noise_facs[e][k] = fac * temp2;

  1119.             }

  1120.         }

  1121.     } else { // SCE or one non-coupled CPE

  1122.         for (ch = 0; ch < (id_aac == TYPE_CPE) + 1; ch++) {

  1123.             float alpha = sbr->data[ch].bs_amp_res ? 1.0f : 0.5f;

  1124.             for (e = 1; e <= sbr->data[ch].bs_num_env; e++)

  1125.                 for (k = 0; k < sbr->n[sbr->data[ch].bs_freq_res[e]]; k++)

  1126.                     sbr->data[ch].env_facs[e][k] =

  1127.                         exp2f(alpha * sbr->data[ch].env_facs[e][k] + 6.0f);

  1128.             for (e = 1; e <= sbr->data[ch].bs_num_noise; e++)

  1129.                 for (k = 0; k < sbr->n_q; k++)

  1130.                     sbr->data[ch].noise_facs[e][k] =

  1131.                         exp2f(NOISE_FLOOR_OFFSET - sbr->data[ch].noise_facs[e][k]);

  1132.         }

  1133.     }

  1134. }

  1135. 

  1136. /**

  1137.  * Analysis QMF Bank (14496-3 sp04 p206)

  1138.  *

  1139.  * @param   x       pointer to the beginning of the first sample window

  1140.  * @param   W       array of complex-valued samples split into subbands

  1141.  */

  1142. static void sbr_qmf_analysis(DSPContext *dsp, FFTContext *mdct, const float *in, float *x,

  1143.                              float z[320], float W[2][32][32][2])

  1144. {

  1145.     int i, k;

  1146.     memcpy(W[0], W[1], sizeof(W[0]));

  1147.     memcpy(x    , x+1024, (320-32)*sizeof(x[0]));

  1148.     memcpy(x+288, in,         1024*sizeof(x[0]));

  1149.     for (i = 0; i < 32; i++) { // numTimeSlots*RATE = 16*2 as 960 sample frames

  1150.                                // are not supported

  1151.         dsp->vector_fmul_reverse(z, sbr_qmf_window_ds, x, 320);

  1152.         for (k = 0; k < 64; k++) {

  1153.             float f = z[k] + z[k + 64] + z[k + 128] + z[k + 192] + z[k + 256];

  1154.             z[k] = f;

  1155.         }

  1156.         //Shuffle to IMDCT

  1157.         z[64] = z[0];

  1158.         for (k = 1; k < 32; k++) {

  1159.             z[64+2*k-1] =  z[   k];

  1160.             z[64+2*k  ] = -z[64-k];

  1161.         }

  1162.         z[64+63] = z[32];

  1163. 

  1164.         mdct->imdct_half(mdct, z, z+64);

  1165.         for (k = 0; k < 32; k++) {

  1166.             W[1][i][k][0] = -z[63-k];

  1167.             W[1][i][k][1] = z[k];

  1168.         }

  1169.         x += 32;

  1170.     }

  1171. }

  1172. 

  1173. /**

  1174.  * Synthesis QMF Bank (14496-3 sp04 p206) and Downsampled Synthesis QMF Bank

  1175.  * (14496-3 sp04 p206)

  1176.  */

  1177. static void sbr_qmf_synthesis(DSPContext *dsp, FFTContext *mdct,

  1178.                               float *out, float X[2][38][64],

  1179.                               float mdct_buf[2][64],

  1180.                               float *v0, int *v_off, const unsigned int div)

  1181. {

  1182.     int i, n;

  1183.     const float *sbr_qmf_window = div ? sbr_qmf_window_ds : sbr_qmf_window_us;

  1184.     float *v;

  1185.     for (i = 0; i < 32; i++) {

  1186.         if (*v_off == 0) {

  1187.             int saved_samples = (1280 - 128) >> div;

  1188.             memcpy(&v0[SBR_SYNTHESIS_BUF_SIZE - saved_samples], v0, saved_samples * sizeof(float));

  1189.             *v_off = SBR_SYNTHESIS_BUF_SIZE - saved_samples - (128 >> div);

  1190.         } else {

  1191.             *v_off -= 128 >> div;

  1192.         }

  1193.         v = v0 + *v_off;

  1194.         if (div) {

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

  1196.                 X[0][i][   n] = -X[0][i][n];

  1197.                 X[0][i][32+n] =  X[1][i][31-n];

  1198.             }

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

  1200.             for (n = 0; n < 32; n++) {

  1201.                 v[     n] =  mdct_buf[0][63 - 2*n];

  1202.                 v[63 - n] = -mdct_buf[0][62 - 2*n];

  1203.             }

  1204.         } else {

  1205.             for (n = 1; n < 64; n+=2) {

  1206.                 X[1][i][n] = -X[1][i][n];

  1207.             }

  1208.             mdct->imdct_half(mdct, mdct_buf[0], X[0][i]);

  1209.             mdct->imdct_half(mdct, mdct_buf[1], X[1][i]);

  1210.             for (n = 0; n < 64; n++) {

  1211.                 v[      n] = -mdct_buf[0][63 -   n] + mdct_buf[1][  n    ];

  1212.                 v[127 - n] =  mdct_buf[0][63 -   n] + mdct_buf[1][  n    ];

  1213.             }

  1214.         }

  1215.         dsp->vector_fmul_add(out, v                , sbr_qmf_window               , zero64, 64 >> div);

  1216.         dsp->vector_fmul_add(out, v + ( 192 >> div), sbr_qmf_window + ( 64 >> div), out   , 64 >> div);

  1217.         dsp->vector_fmul_add(out, v + ( 256 >> div), sbr_qmf_window + (128 >> div), out   , 64 >> div);

  1218.         dsp->vector_fmul_add(out, v + ( 448 >> div), sbr_qmf_window + (192 >> div), out   , 64 >> div);

  1219.         dsp->vector_fmul_add(out, v + ( 512 >> div), sbr_qmf_window + (256 >> div), out   , 64 >> div);

  1220.         dsp->vector_fmul_add(out, v + ( 704 >> div), sbr_qmf_window + (320 >> div), out   , 64 >> div);

  1221.         dsp->vector_fmul_add(out, v + ( 768 >> div), sbr_qmf_window + (384 >> div), out   , 64 >> div);

  1222.         dsp->vector_fmul_add(out, v + ( 960 >> div), sbr_qmf_window + (448 >> div), out   , 64 >> div);

  1223.         dsp->vector_fmul_add(out, v + (1024 >> div), sbr_qmf_window + (512 >> div), out   , 64 >> div);

  1224.         dsp->vector_fmul_add(out, v + (1216 >> div), sbr_qmf_window + (576 >> div), out   , 64 >> div);

  1225.         out += 64 >> div;

  1226.     }

  1227. }

  1228. 

  1229. static void autocorrelate(const float x[40][2], float phi[3][2][2], int lag)

  1230. {

  1231.     int i;

  1232.     float real_sum = 0.0f;

  1233.     float imag_sum = 0.0f;

  1234.     if (lag) {

  1235.         for (i = 1; i < 38; i++) {

  1236.             real_sum += x[i][0] * x[i+lag][0] + x[i][1] * x[i+lag][1];

  1237.             imag_sum += x[i][0] * x[i+lag][1] - x[i][1] * x[i+lag][0];

  1238.         }

  1239.         phi[2-lag][1][0] = real_sum + x[ 0][0] * x[lag][0] + x[ 0][1] * x[lag][1];

  1240.         phi[2-lag][1][1] = imag_sum + x[ 0][0] * x[lag][1] - x[ 0][1] * x[lag][0];

  1241.         if (lag == 1) {

  1242.             phi[0][0][0] = real_sum + x[38][0] * x[39][0] + x[38][1] * x[39][1];

  1243.             phi[0][0][1] = imag_sum + x[38][0] * x[39][1] - x[38][1] * x[39][0];

  1244.         }

  1245.     } else {

  1246.         for (i = 1; i < 38; i++) {

  1247.             real_sum += x[i][0] * x[i][0] + x[i][1] * x[i][1];

  1248.         }

  1249.         phi[2][1][0] = real_sum + x[ 0][0] * x[ 0][0] + x[ 0][1] * x[ 0][1];

  1250.         phi[1][0][0] = real_sum + x[38][0] * x[38][0] + x[38][1] * x[38][1];

  1251.     }

  1252. }

  1253. 

  1254. /** High Frequency Generation (14496-3 sp04 p214+) and Inverse Filtering

  1255.  * (14496-3 sp04 p214)

  1256.  * Warning: This routine does not seem numerically stable.

  1257.  */

  1258. static void sbr_hf_inverse_filter(float (*alpha0)[2], float (*alpha1)[2],

  1259.                                   const float X_low[32][40][2], int k0)

  1260. {

  1261.     int k;

  1262.     for (k = 0; k < k0; k++) {

  1263.         float phi[3][2][2], dk;

  1264. 

  1265.         autocorrelate(X_low[k], phi, 0);

  1266.         autocorrelate(X_low[k], phi, 1);

  1267.         autocorrelate(X_low[k], phi, 2);

  1268. 

  1269.         dk =  phi[2][1][0] * phi[1][0][0] -

  1270.              (phi[1][1][0] * phi[1][1][0] + phi[1][1][1] * phi[1][1][1]) / 1.000001f;

  1271. 

  1272.         if (!dk) {

  1273.             alpha1[k][0] = 0;

  1274.             alpha1[k][1] = 0;

  1275.         } else {

  1276.             float temp_real, temp_im;

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

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

  1279.                         phi[0][1][0] * phi[1][0][0];

  1280.             temp_im   = phi[0][0][0] * phi[1][1][1] +

  1281.                         phi[0][0][1] * phi[1][1][0] -

  1282.                         phi[0][1][1] * phi[1][0][0];

  1283. 

  1284.             alpha1[k][0] = temp_real / dk;

  1285.             alpha1[k][1] = temp_im   / dk;

  1286.         }

  1287. 

  1288.         if (!phi[1][0][0]) {

  1289.             alpha0[k][0] = 0;

  1290.             alpha0[k][1] = 0;

  1291.         } else {

  1292.             float temp_real, temp_im;

  1293.             temp_real = phi[0][0][0] + alpha1[k][0] * phi[1][1][0] +

  1294.                                        alpha1[k][1] * phi[1][1][1];

  1295.             temp_im   = phi[0][0][1] + alpha1[k][1] * phi[1][1][0] -

  1296.                                        alpha1[k][0] * phi[1][1][1];

  1297. 

  1298.             alpha0[k][0] = -temp_real / phi[1][0][0];

  1299.             alpha0[k][1] = -temp_im   / phi[1][0][0];

  1300.         }

  1301. 

  1302.         if (alpha1[k][0] * alpha1[k][0] + alpha1[k][1] * alpha1[k][1] >= 16.0f ||

  1303.            alpha0[k][0] * alpha0[k][0] + alpha0[k][1] * alpha0[k][1] >= 16.0f) {

  1304.             alpha1[k][0] = 0;

  1305.             alpha1[k][1] = 0;

  1306.             alpha0[k][0] = 0;

  1307.             alpha0[k][1] = 0;

  1308.         }

  1309.     }

  1310. }

  1311. 

  1312. /// Chirp Factors (14496-3 sp04 p214)

  1313. static void sbr_chirp(SpectralBandReplication *sbr, SBRData *ch_data)

  1314. {

  1315.     int i;

  1316.     float new_bw;

  1317.     static const float bw_tab[] = { 0.0f, 0.75f, 0.9f, 0.98f };

  1318. 

  1319.     for (i = 0; i < sbr->n_q; i++) {

  1320.         if (ch_data->bs_invf_mode[0][i] + ch_data->bs_invf_mode[1][i] == 1) {

  1321.             new_bw = 0.6f;

  1322.         } else

  1323.             new_bw = bw_tab[ch_data->bs_invf_mode[0][i]];

  1324. 

  1325.         if (new_bw < ch_data->bw_array[i]) {

  1326.             new_bw = 0.75f    * new_bw + 0.25f    * ch_data->bw_array[i];

  1327.         } else

  1328.             new_bw = 0.90625f * new_bw + 0.09375f * ch_data->bw_array[i];

  1329.         ch_data->bw_array[i] = new_bw < 0.015625f ? 0.0f : new_bw;

  1330.     }

  1331. }

  1332. 

  1333. /// Generate the subband filtered lowband

  1334. static int sbr_lf_gen(AACContext *ac, SpectralBandReplication *sbr,

  1335.                       float X_low[32][40][2], const float W[2][32][32][2])

  1336. {

  1337.     int i, k;

  1338.     const int t_HFGen = 8;

  1339.     const int i_f = 32;

  1340.     memset(X_low, 0, 32*sizeof(*X_low));

  1341.     for (k = 0; k < sbr->kx[1]; k++) {

  1342.         for (i = t_HFGen; i < i_f + t_HFGen; i++) {

  1343.             X_low[k][i][0] = W[1][i - t_HFGen][k][0];

  1344.             X_low[k][i][1] = W[1][i - t_HFGen][k][1];

  1345.         }

  1346.     }

  1347.     for (k = 0; k < sbr->kx[0]; k++) {

  1348.         for (i = 0; i < t_HFGen; i++) {

  1349.             X_low[k][i][0] = W[0][i + i_f - t_HFGen][k][0];

  1350.             X_low[k][i][1] = W[0][i + i_f - t_HFGen][k][1];

  1351.         }

  1352.     }

  1353.     return 0;

  1354. }

  1355. 

  1356. /// High Frequency Generator (14496-3 sp04 p215)

  1357. static int sbr_hf_gen(AACContext *ac, SpectralBandReplication *sbr,

  1358.                       float X_high[64][40][2], const float X_low[32][40][2],

  1359.                       const float (*alpha0)[2], const float (*alpha1)[2],

  1360.                       const float bw_array[5], const uint8_t *t_env,

  1361.                       int bs_num_env)

  1362. {

  1363.     int i, j, x;

  1364.     int g = 0;

  1365.     int k = sbr->kx[1];

  1366.     for (j = 0; j < sbr->num_patches; j++) {

  1367.         for (x = 0; x < sbr->patch_num_subbands[j]; x++, k++) {

  1368.             float alpha[4];

  1369.             const int p = sbr->patch_start_subband[j] + x;

  1370.             while (g <= sbr->n_q && k >= sbr->f_tablenoise[g])

  1371.                 g++;

  1372.             g--;

  1373. 

  1374.             if (g < 0) {

  1375.                 av_log(ac->avctx, AV_LOG_ERROR,

  1376.                        "ERROR : no subband found for frequency %d\n", k);

  1377.                 return -1;

  1378.             }

  1379. 

  1380.             alpha[0] = alpha1[p][0] * bw_array[g] * bw_array[g];

  1381.             alpha[1] = alpha1[p][1] * bw_array[g] * bw_array[g];

  1382.             alpha[2] = alpha0[p][0] * bw_array[g];

  1383.             alpha[3] = alpha0[p][1] * bw_array[g];

  1384. 

  1385.             for (i = 2 * t_env[0]; i < 2 * t_env[bs_num_env]; i++) {

  1386.                 const int idx = i + ENVELOPE_ADJUSTMENT_OFFSET;

  1387.                 X_high[k][idx][0] =

  1388.                     X_low[p][idx - 2][0] * alpha[0] -

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

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

  1391.                     X_low[p][idx - 1][1] * alpha[3] +

  1392.                     X_low[p][idx][0];

  1393.                 X_high[k][idx][1] =

  1394.                     X_low[p][idx - 2][1] * alpha[0] +

  1395.                     X_low[p][idx - 2][0] * alpha[1] +

  1396.                     X_low[p][idx - 1][1] * alpha[2] +

  1397.                     X_low[p][idx - 1][0] * alpha[3] +

  1398.                     X_low[p][idx][1];

  1399.             }

  1400.         }

  1401.     }

  1402.     if (k < sbr->m[1] + sbr->kx[1])

  1403.         memset(X_high + k, 0, (sbr->m[1] + sbr->kx[1] - k) * sizeof(*X_high));

  1404. 

  1405.     return 0;

  1406. }

  1407. 

  1408. /// Generate the subband filtered lowband

  1409. static int sbr_x_gen(SpectralBandReplication *sbr, float X[2][38][64],

  1410.                      const float X_low[32][40][2], const float Y[2][38][64][2],

  1411.                      int ch)

  1412. {

  1413.     int k, i;

  1414.     const int i_f = 32;

  1415.     const int i_Temp = FFMAX(2*sbr->data[ch].t_env_num_env_old - i_f, 0);

  1416.     memset(X, 0, 2*sizeof(*X));

  1417.     for (k = 0; k < sbr->kx[0]; k++) {

  1418.         for (i = 0; i < i_Temp; i++) {

  1419.             X[0][i][k] = X_low[k][i + ENVELOPE_ADJUSTMENT_OFFSET][0];

  1420.             X[1][i][k] = X_low[k][i + ENVELOPE_ADJUSTMENT_OFFSET][1];

  1421.         }

  1422.     }

  1423.     for (; k < sbr->kx[0] + sbr->m[0]; k++) {

  1424.         for (i = 0; i < i_Temp; i++) {

  1425.             X[0][i][k] = Y[0][i + i_f][k][0];

  1426.             X[1][i][k] = Y[0][i + i_f][k][1];

  1427.         }

  1428.     }

  1429. 

  1430.     for (k = 0; k < sbr->kx[1]; k++) {

  1431.         for (i = i_Temp; i < 38; i++) {

  1432.             X[0][i][k] = X_low[k][i + ENVELOPE_ADJUSTMENT_OFFSET][0];

  1433.             X[1][i][k] = X_low[k][i + ENVELOPE_ADJUSTMENT_OFFSET][1];

  1434.         }

  1435.     }

  1436.     for (; k < sbr->kx[1] + sbr->m[1]; k++) {

  1437.         for (i = i_Temp; i < i_f; i++) {

  1438.             X[0][i][k] = Y[1][i][k][0];

  1439.             X[1][i][k] = Y[1][i][k][1];

  1440.         }

  1441.     }

  1442.     return 0;

  1443. }

  1444. 

  1445. /** High Frequency Adjustment (14496-3 sp04 p217) and Mapping

  1446.  * (14496-3 sp04 p217)

  1447.  */

  1448. static void sbr_mapping(AACContext *ac, SpectralBandReplication *sbr,

  1449.                         SBRData *ch_data, int e_a[2])

  1450. {

  1451.     int e, i, m;

  1452. 

  1453.     memset(ch_data->s_indexmapped[1], 0, 7*sizeof(ch_data->s_indexmapped[1]));

  1454.     for (e = 0; e < ch_data->bs_num_env; e++) {

  1455.         const unsigned int ilim = sbr->n[ch_data->bs_freq_res[e + 1]];

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

  1457.         int k;

  1458. 

  1459.         for (i = 0; i < ilim; i++)

  1460.             for (m = table[i]; m < table[i + 1]; m++)

  1461.                 sbr->e_origmapped[e][m - sbr->kx[1]] = ch_data->env_facs[e+1][i];

  1462. 

  1463.         // ch_data->bs_num_noise > 1 => 2 noise floors

  1464.         k = (ch_data->bs_num_noise > 1) && (ch_data->t_env[e] >= ch_data->t_q[1]);

  1465.         for (i = 0; i < sbr->n_q; i++)

  1466.             for (m = sbr->f_tablenoise[i]; m < sbr->f_tablenoise[i + 1]; m++)

  1467.                 sbr->q_mapped[e][m - sbr->kx[1]] = ch_data->noise_facs[k+1][i];

  1468. 

  1469.         for (i = 0; i < sbr->n[1]; i++) {

  1470.             if (ch_data->bs_add_harmonic_flag) {

  1471.                 const unsigned int m_midpoint =

  1472.                     (sbr->f_tablehigh[i] + sbr->f_tablehigh[i + 1]) >> 1;

  1473. 

  1474.                 ch_data->s_indexmapped[e + 1][m_midpoint - sbr->kx[1]] = ch_data->bs_add_harmonic[i] *

  1475.                     (e >= e_a[1] || (ch_data->s_indexmapped[0][m_midpoint - sbr->kx[1]] == 1));

  1476.             }

  1477.         }

  1478. 

  1479.         for (i = 0; i < ilim; i++) {

  1480.             int additional_sinusoid_present = 0;

  1481.             for (m = table[i]; m < table[i + 1]; m++) {

  1482.                 if (ch_data->s_indexmapped[e + 1][m - sbr->kx[1]]) {

  1483.                     additional_sinusoid_present = 1;

  1484.                     break;

  1485.                 }

  1486.             }

  1487.             memset(&sbr->s_mapped[e][table[i] - sbr->kx[1]], additional_sinusoid_present,

  1488.                    (table[i + 1] - table[i]) * sizeof(sbr->s_mapped[e][0]));

  1489.         }

  1490.     }

  1491. 

  1492.     memcpy(ch_data->s_indexmapped[0], ch_data->s_indexmapped[ch_data->bs_num_env], sizeof(ch_data->s_indexmapped[0]));

  1493. }

  1494. 

  1495. /// Estimation of current envelope (14496-3 sp04 p218)

  1496. static void sbr_env_estimate(float (*e_curr)[48], float X_high[64][40][2],

  1497.                              SpectralBandReplication *sbr, SBRData *ch_data)

  1498. {

  1499.     int e, i, m;

  1500. 

  1501.     if (sbr->bs_interpol_freq) {

  1502.         for (e = 0; e < ch_data->bs_num_env; e++) {

  1503.             const float recip_env_size = 0.5f / (ch_data->t_env[e + 1] - ch_data->t_env[e]);

  1504.             int ilb = ch_data->t_env[e]     * 2 + ENVELOPE_ADJUSTMENT_OFFSET;

  1505.             int iub = ch_data->t_env[e + 1] * 2 + ENVELOPE_ADJUSTMENT_OFFSET;

  1506. 

  1507.             for (m = 0; m < sbr->m[1]; m++) {

  1508.                 float sum = 0.0f;

  1509. 

  1510.                 for (i = ilb; i < iub; i++) {

  1511.                     sum += X_high[m + sbr->kx[1]][i][0] * X_high[m + sbr->kx[1]][i][0] +

  1512.                            X_high[m + sbr->kx[1]][i][1] * X_high[m + sbr->kx[1]][i][1];

  1513.                 }

  1514.                 e_curr[e][m] = sum * recip_env_size;

  1515.             }

  1516.         }

  1517.     } else {

  1518.         int k, p;

  1519. 

  1520.         for (e = 0; e < ch_data->bs_num_env; e++) {

  1521.             const int env_size = 2 * (ch_data->t_env[e + 1] - ch_data->t_env[e]);

  1522.             int ilb = ch_data->t_env[e]     * 2 + ENVELOPE_ADJUSTMENT_OFFSET;

  1523.             int iub = ch_data->t_env[e + 1] * 2 + ENVELOPE_ADJUSTMENT_OFFSET;

  1524.             const uint16_t *table = ch_data->bs_freq_res[e + 1] ? sbr->f_tablehigh : sbr->f_tablelow;

  1525. 

  1526.             for (p = 0; p < sbr->n[ch_data->bs_freq_res[e + 1]]; p++) {

  1527.                 float sum = 0.0f;

  1528.                 const int den = env_size * (table[p + 1] - table[p]);

  1529. 

  1530.                 for (k = table[p]; k < table[p + 1]; k++) {

  1531.                     for (i = ilb; i < iub; i++) {

  1532.                         sum += X_high[k][i][0] * X_high[k][i][0] +

  1533.                                X_high[k][i][1] * X_high[k][i][1];

  1534.                     }

  1535.                 }

  1536.                 sum /= den;

  1537.                 for (k = table[p]; k < table[p + 1]; k++) {

  1538.                     e_curr[e][k - sbr->kx[1]] = sum;

  1539.                 }

  1540.             }

  1541.         }

  1542.     }

  1543. }

  1544. 

  1545. /**

  1546.  * Calculation of levels of additional HF signal components (14496-3 sp04 p219)

  1547.  * and Calculation of gain (14496-3 sp04 p219)

  1548.  */

  1549. static void sbr_gain_calc(AACContext *ac, SpectralBandReplication *sbr,

  1550.                           SBRData *ch_data, const int e_a[2])

  1551. {

  1552.     int e, k, m;

  1553.     // max gain limits : -3dB, 0dB, 3dB, inf dB (limiter off)

  1554.     static const float limgain[4] = { 0.70795, 1.0, 1.41254, 10000000000 };

  1555. 

  1556.     for (e = 0; e < ch_data->bs_num_env; e++) {

  1557.         int delta = !((e == e_a[1]) || (e == e_a[0]));

  1558.         for (k = 0; k < sbr->n_lim; k++) {

  1559.             float gain_boost, gain_max;

  1560.             float sum[2] = { 0.0f, 0.0f };

  1561.             for (m = sbr->f_tablelim[k] - sbr->kx[1]; m < sbr->f_tablelim[k + 1] - sbr->kx[1]; m++) {

  1562.                 const float temp = sbr->e_origmapped[e][m] / (1.0f + sbr->q_mapped[e][m]);

  1563.                 sbr->q_m[e][m] = sqrtf(temp * sbr->q_mapped[e][m]);

  1564.                 sbr->s_m[e][m] = sqrtf(temp * ch_data->s_indexmapped[e + 1][m]);

  1565.                 if (!sbr->s_mapped[e][m]) {

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

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

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

  1569.                 } else {

  1570.                     sbr->gain[e][m] = sqrtf(sbr->e_origmapped[e][m] * sbr->q_mapped[e][m] /

  1571.                                             ((1.0f + sbr->e_curr[e][m]) *

  1572.                                              (1.0f + sbr->q_mapped[e][m])));

  1573.                 }

  1574.             }

  1575.             for (m = sbr->f_tablelim[k] - sbr->kx[1]; m < sbr->f_tablelim[k + 1] - sbr->kx[1]; m++) {

  1576.                 sum[0] += sbr->e_origmapped[e][m];

  1577.                 sum[1] += sbr->e_curr[e][m];

  1578.             }

  1579.             gain_max = limgain[sbr->bs_limiter_gains] * sqrtf((FLT_EPSILON + sum[0]) / (FLT_EPSILON + sum[1]));

  1580.             gain_max = FFMIN(100000.f, gain_max);

  1581.             for (m = sbr->f_tablelim[k] - sbr->kx[1]; m < sbr->f_tablelim[k + 1] - sbr->kx[1]; m++) {

  1582.                 float q_m_max   = sbr->q_m[e][m] * gain_max / sbr->gain[e][m];

  1583.                 sbr->q_m[e][m]  = FFMIN(sbr->q_m[e][m], q_m_max);

  1584.                 sbr->gain[e][m] = FFMIN(sbr->gain[e][m], gain_max);

  1585.             }

  1586.             sum[0] = sum[1] = 0.0f;

  1587.             for (m = sbr->f_tablelim[k] - sbr->kx[1]; m < sbr->f_tablelim[k + 1] - sbr->kx[1]; m++) {

  1588.                 sum[0] += sbr->e_origmapped[e][m];

  1589.                 sum[1] += sbr->e_curr[e][m] * sbr->gain[e][m] * sbr->gain[e][m]

  1590.                           + sbr->s_m[e][m] * sbr->s_m[e][m]

  1591.                           + (delta && !sbr->s_m[e][m]) * sbr->q_m[e][m] * sbr->q_m[e][m];

  1592.             }

  1593.             gain_boost = sqrtf((FLT_EPSILON + sum[0]) / (FLT_EPSILON + sum[1]));

  1594.             gain_boost = FFMIN(1.584893192f, gain_boost);

  1595.             for (m = sbr->f_tablelim[k] - sbr->kx[1]; m < sbr->f_tablelim[k + 1] - sbr->kx[1]; m++) {

  1596.                 sbr->gain[e][m] *= gain_boost;

  1597.                 sbr->q_m[e][m]  *= gain_boost;

  1598.                 sbr->s_m[e][m]  *= gain_boost;

  1599.             }

  1600.         }

  1601.     }

  1602. }

  1603. 

  1604. /// Assembling HF Signals (14496-3 sp04 p220)

  1605. static void sbr_hf_assemble(float Y[2][38][64][2], const float X_high[64][40][2],

  1606.                             SpectralBandReplication *sbr, SBRData *ch_data,

  1607.                             const int e_a[2])

  1608. {

  1609.     int e, i, j, m;

  1610.     const int h_SL = 4 * !sbr->bs_smoothing_mode;

  1611.     const int kx = sbr->kx[1];

  1612.     const int m_max = sbr->m[1];

  1613.     static const float h_smooth[5] = {

  1614.         0.33333333333333,

  1615.         0.30150283239582,

  1616.         0.21816949906249,

  1617.         0.11516383427084,

  1618.         0.03183050093751,

  1619.     };

  1620.     static const int8_t phi[2][4] = {

  1621.         {  1,  0, -1,  0}, // real

  1622.         {  0,  1,  0, -1}, // imaginary

  1623.     };

  1624.     float (*g_temp)[48] = ch_data->g_temp, (*q_temp)[48] = ch_data->q_temp;

  1625.     int indexnoise = ch_data->f_indexnoise;

  1626.     int indexsine  = ch_data->f_indexsine;

  1627.     memcpy(Y[0], Y[1], sizeof(Y[0]));

  1628. 

  1629.     if (sbr->reset) {

  1630.         for (i = 0; i < h_SL; i++) {

  1631.             memcpy(g_temp[i + 2*ch_data->t_env[0]], sbr->gain[0], m_max * sizeof(sbr->gain[0][0]));

  1632.             memcpy(q_temp[i + 2*ch_data->t_env[0]], sbr->q_m[0],  m_max * sizeof(sbr->q_m[0][0]));

  1633.         }

  1634.     } else if (h_SL) {

  1635.         memcpy(g_temp[2*ch_data->t_env[0]], g_temp[2*ch_data->t_env_num_env_old], 4*sizeof(g_temp[0]));

  1636.         memcpy(q_temp[2*ch_data->t_env[0]], q_temp[2*ch_data->t_env_num_env_old], 4*sizeof(q_temp[0]));

  1637.     }

  1638. 

  1639.     for (e = 0; e < ch_data->bs_num_env; e++) {

  1640.         for (i = 2 * ch_data->t_env[e]; i < 2 * ch_data->t_env[e + 1]; i++) {

  1641.             memcpy(g_temp[h_SL + i], sbr->gain[e], m_max * sizeof(sbr->gain[0][0]));

  1642.             memcpy(q_temp[h_SL + i], sbr->q_m[e],  m_max * sizeof(sbr->q_m[0][0]));

  1643.         }

  1644.     }

  1645. 

  1646.     for (e = 0; e < ch_data->bs_num_env; e++) {

  1647.         for (i = 2 * ch_data->t_env[e]; i < 2 * ch_data->t_env[e + 1]; i++) {

  1648.             int phi_sign = (1 - 2*(kx & 1));

  1649. 

  1650.             if (h_SL && e != e_a[0] && e != e_a[1]) {

  1651.                 for (m = 0; m < m_max; m++) {

  1652.                     const int idx1 = i + h_SL;

  1653.                     float g_filt = 0.0f;

  1654.                     for (j = 0; j <= h_SL; j++)

  1655.                         g_filt += g_temp[idx1 - j][m] * h_smooth[j];

  1656.                     Y[1][i][m + kx][0] =

  1657.                         X_high[m + kx][i + ENVELOPE_ADJUSTMENT_OFFSET][0] * g_filt;

  1658.                     Y[1][i][m + kx][1] =

  1659.                         X_high[m + kx][i + ENVELOPE_ADJUSTMENT_OFFSET][1] * g_filt;

  1660.                 }

  1661.             } else {

  1662.                 for (m = 0; m < m_max; m++) {

  1663.                     const float g_filt = g_temp[i + h_SL][m];

  1664.                     Y[1][i][m + kx][0] =

  1665.                         X_high[m + kx][i + ENVELOPE_ADJUSTMENT_OFFSET][0] * g_filt;

  1666.                     Y[1][i][m + kx][1] =

  1667.                         X_high[m + kx][i + ENVELOPE_ADJUSTMENT_OFFSET][1] * g_filt;

  1668.                 }

  1669.             }

  1670. 

  1671.             if (e != e_a[0] && e != e_a[1]) {

  1672.                 for (m = 0; m < m_max; m++) {

  1673.                     indexnoise = (indexnoise + 1) & 0x1ff;

  1674.                     if (sbr->s_m[e][m]) {

  1675.                         Y[1][i][m + kx][0] +=

  1676.                             sbr->s_m[e][m] * phi[0][indexsine];

  1677.                         Y[1][i][m + kx][1] +=

  1678.                             sbr->s_m[e][m] * (phi[1][indexsine] * phi_sign);

  1679.                     } else {

  1680.                         float q_filt;

  1681.                         if (h_SL) {

  1682.                             const int idx1 = i + h_SL;

  1683.                             q_filt = 0.0f;

  1684.                             for (j = 0; j <= h_SL; j++)

  1685.                                 q_filt += q_temp[idx1 - j][m] * h_smooth[j];

  1686.                         } else {

  1687.                             q_filt = q_temp[i][m];

  1688.                         }

  1689.                         Y[1][i][m + kx][0] +=

  1690.                             q_filt * sbr_noise_table[indexnoise][0];

  1691.                         Y[1][i][m + kx][1] +=

  1692.                             q_filt * sbr_noise_table[indexnoise][1];

  1693.                     }

  1694.                     phi_sign = -phi_sign;

  1695.                 }

  1696.             } else {

  1697.                 indexnoise = (indexnoise + m_max) & 0x1ff;

  1698.                 for (m = 0; m < m_max; m++) {

  1699.                     Y[1][i][m + kx][0] +=

  1700.                         sbr->s_m[e][m] * phi[0][indexsine];

  1701.                     Y[1][i][m + kx][1] +=

  1702.                         sbr->s_m[e][m] * (phi[1][indexsine] * phi_sign);

  1703.                     phi_sign = -phi_sign;

  1704.                 }

  1705.             }

  1706.             indexsine = (indexsine + 1) & 3;

  1707.         }

  1708.     }

  1709.     ch_data->f_indexnoise = indexnoise;

  1710.     ch_data->f_indexsine  = indexsine;

  1711. }

  1712. 

  1713. void ff_sbr_apply(AACContext *ac, SpectralBandReplication *sbr, int id_aac,

  1714.                   float* L, float* R)

  1715. {

  1716.     int downsampled = ac->m4ac.ext_sample_rate < sbr->sample_rate;

  1717.     int ch;

  1718.     int nch = (id_aac == TYPE_CPE) ? 2 : 1;

  1719. 

  1720.     if (sbr->start) {

  1721.         sbr_dequant(sbr, id_aac);

  1722.     }

  1723.     for (ch = 0; ch < nch; ch++) {

  1724.         /* decode channel */

  1725.         sbr_qmf_analysis(&ac->dsp, &sbr->mdct_ana, ch ? R : L, sbr->data[ch].analysis_filterbank_samples,

  1726.                          (float*)sbr->qmf_filter_scratch,

  1727.                          sbr->data[ch].W);

  1728.         sbr_lf_gen(ac, sbr, sbr->X_low, sbr->data[ch].W);

  1729.         if (sbr->start) {

  1730.             sbr_hf_inverse_filter(sbr->alpha0, sbr->alpha1, sbr->X_low, sbr->k[0]);

  1731.             sbr_chirp(sbr, &sbr->data[ch]);

  1732.             sbr_hf_gen(ac, sbr, sbr->X_high, sbr->X_low, sbr->alpha0, sbr->alpha1,

  1733.                        sbr->data[ch].bw_array, sbr->data[ch].t_env,

  1734.                        sbr->data[ch].bs_num_env);

  1735. 

  1736.             // hf_adj

  1737.             sbr_mapping(ac, sbr, &sbr->data[ch], sbr->data[ch].e_a);

  1738.             sbr_env_estimate(sbr->e_curr, sbr->X_high, sbr, &sbr->data[ch]);

  1739.             sbr_gain_calc(ac, sbr, &sbr->data[ch], sbr->data[ch].e_a);

  1740.             sbr_hf_assemble(sbr->data[ch].Y, sbr->X_high, sbr, &sbr->data[ch],

  1741.                             sbr->data[ch].e_a);

  1742.         }

  1743. 

  1744.         /* synthesis */

  1745.         sbr_x_gen(sbr, sbr->X[ch], sbr->X_low, sbr->data[ch].Y, ch);

  1746.     }

  1747. 

  1748.     if (ac->m4ac.ps == 1) {

  1749.         if (sbr->ps.start) {

  1750.             ff_ps_apply(ac->avctx, &sbr->ps, sbr->X[0], sbr->X[1], sbr->kx[1] + sbr->m[1]);

  1751.         } else {

  1752.             memcpy(sbr->X[1], sbr->X[0], sizeof(sbr->X[0]));

  1753.         }

  1754.         nch = 2;

  1755.     }

  1756. 

  1757.     sbr_qmf_synthesis(&ac->dsp, &sbr->mdct, L, sbr->X[0], sbr->qmf_filter_scratch,

  1758.                       sbr->data[0].synthesis_filterbank_samples,

  1759.                       &sbr->data[0].synthesis_filterbank_samples_offset,

  1760.                       downsampled);

  1761.     if (nch == 2)

  1762.         sbr_qmf_synthesis(&ac->dsp, &sbr->mdct, R, sbr->X[1], sbr->qmf_filter_scratch,

  1763.                           sbr->data[1].synthesis_filterbank_samples,

  1764.                           &sbr->data[1].synthesis_filterbank_samples_offset,

  1765.                           downsampled);

  1766. }