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FFmpeg/libavcodec/aacsbr.c

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  1. /*

  2.  * AAC Spectral Band Replication decoding functions

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

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

  5.  *

  6.  * This file is part of FFmpeg.

  7.  *

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

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

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

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

  12.  *

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

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

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

  16.  * Lesser General Public License for more details.

  17.  *

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

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

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

  21.  */

  22. 

  23. /**

  24.  * @file

  25.  * AAC Spectral Band Replication decoding functions

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

  27.  */

  28. 

  29. #include "aac.h"

  30. #include "sbr.h"

  31. #include "aacsbr.h"

  32. #include "aacsbrdata.h"

  33. #include "fft.h"

  34. #include "aacps.h"

  35. 

  36. #include <stdint.h>

  37. #include <float.h>

  38. 

  39. #define ENVELOPE_ADJUSTMENT_OFFSET 2

  40. #define NOISE_FLOOR_OFFSET 6.0f

  41. 

  42. /**

  43.  * SBR VLC tables

  44.  */

  45. enum {

  46.     T_HUFFMAN_ENV_1_5DB,

  47.     F_HUFFMAN_ENV_1_5DB,

  48.     T_HUFFMAN_ENV_BAL_1_5DB,

  49.     F_HUFFMAN_ENV_BAL_1_5DB,

  50.     T_HUFFMAN_ENV_3_0DB,

  51.     F_HUFFMAN_ENV_3_0DB,

  52.     T_HUFFMAN_ENV_BAL_3_0DB,

  53.     F_HUFFMAN_ENV_BAL_3_0DB,

  54.     T_HUFFMAN_NOISE_3_0DB,

  55.     T_HUFFMAN_NOISE_BAL_3_0DB,

  56. };

  57. 

  58. /**

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

  60.  */

  61. enum {

  62.     FIXFIX,

  63.     FIXVAR,

  64.     VARFIX,

  65.     VARVAR,

  66. };

  67. 

  68. enum {

  69.     EXTENSION_ID_PS = 2,

  70. };

  71. 

  72. static VLC vlc_sbr[10];

  73. static const int8_t vlc_sbr_lav[10] =

  74.     { 60, 60, 24, 24, 31, 31, 12, 12, 31, 12 };

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

  76. 

  77. #define SBR_INIT_VLC_STATIC(num, size) \

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

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

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

  81.                     size)

  82. 

  83. #define SBR_VLC_ROW(name) \

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

  85. 

  86. av_cold void ff_aac_sbr_init(void)

  87. {

  88.     int n;

  89.     static const struct {

  90.         const void *sbr_codes, *sbr_bits;

  91.         const unsigned int table_size, elem_size;

  92.     } sbr_tmp[] = {

  93.         SBR_VLC_ROW(t_huffman_env_1_5dB),

  94.         SBR_VLC_ROW(f_huffman_env_1_5dB),

  95.         SBR_VLC_ROW(t_huffman_env_bal_1_5dB),

  96.         SBR_VLC_ROW(f_huffman_env_bal_1_5dB),

  97.         SBR_VLC_ROW(t_huffman_env_3_0dB),

  98.         SBR_VLC_ROW(f_huffman_env_3_0dB),

  99.         SBR_VLC_ROW(t_huffman_env_bal_3_0dB),

  100.         SBR_VLC_ROW(f_huffman_env_bal_3_0dB),

  101.         SBR_VLC_ROW(t_huffman_noise_3_0dB),

  102.         SBR_VLC_ROW(t_huffman_noise_bal_3_0dB),

  103.     };

  104. 

  105.     // SBR VLC table initialization

  106.     SBR_INIT_VLC_STATIC(0, 1098);

  107.     SBR_INIT_VLC_STATIC(1, 1092);

  108.     SBR_INIT_VLC_STATIC(2, 768);

  109.     SBR_INIT_VLC_STATIC(3, 1026);

  110.     SBR_INIT_VLC_STATIC(4, 1058);

  111.     SBR_INIT_VLC_STATIC(5, 1052);

  112.     SBR_INIT_VLC_STATIC(6, 544);

  113.     SBR_INIT_VLC_STATIC(7, 544);

  114.     SBR_INIT_VLC_STATIC(8, 592);

  115.     SBR_INIT_VLC_STATIC(9, 512);

  116. 

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

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

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

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

  121. 

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

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

  124. 

  125.     ff_ps_init();

  126. }

  127. 

  128. av_cold void ff_aac_sbr_ctx_init(SpectralBandReplication *sbr)

  129. {

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

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

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

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

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

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

  136.     ff_ps_ctx_init(&sbr->ps);

  137. }

  138. 

  139. av_cold void ff_aac_sbr_ctx_close(SpectralBandReplication *sbr)

  140. {

  141.     ff_mdct_end(&sbr->mdct);

  142.     ff_mdct_end(&sbr->mdct_ana);

  143. }

  144. 

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

  146. {

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

  148. }

  149. 

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

  151. {

  152.     int i;

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

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

  155.             return 1;

  156.     return 0;

  157. }

  158. 

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

  160. static void sbr_make_f_tablelim(SpectralBandReplication *sbr)

  161. {

  162.     int k;

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

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

  165.                                                1.18509277094158210129f,   //2^(0.49/2)

  166.                                                1.11987160404675912501f }; //2^(0.49/3)

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

  168.         int16_t patch_borders[7];

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

  170. 

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

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

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

  174. 

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

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

  177.         if (sbr->num_patches > 1)

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

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

  180. 

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

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

  183.               qsort_comparison_function_int16);

  184. 

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

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

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

  188.                 *++out = *in++;

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

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

  191.                 in++;

  192.                 sbr->n_lim--;

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

  194.                 *out = *in++;

  195.                 sbr->n_lim--;

  196.             } else {

  197.                 *++out = *in++;

  198.             }

  199.         }

  200.     } else {

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

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

  203.         sbr->n_lim = 1;

  204.     }

  205. }

  206. 

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

  208. {

  209.     unsigned int cnt = get_bits_count(gb);

  210.     uint8_t bs_header_extra_1;

  211.     uint8_t bs_header_extra_2;

  212.     int old_bs_limiter_bands = sbr->bs_limiter_bands;

  213.     SpectrumParameters old_spectrum_params;

  214. 

  215.     sbr->start = 1;

  216. 

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

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

  219. 

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

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

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

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

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

  225. 

  226.     bs_header_extra_1 = get_bits1(gb);

  227.     bs_header_extra_2 = get_bits1(gb);

  228. 

  229.     if (bs_header_extra_1) {

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

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

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

  233.     } else {

  234.         sbr->spectrum_params.bs_freq_scale  = 2;

  235.         sbr->spectrum_params.bs_alter_scale = 1;

  236.         sbr->spectrum_params.bs_noise_bands = 2;

  237.     }

  238. 

  239.     // Check if spectrum parameters changed

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

  241.         sbr->reset = 1;

  242. 

  243.     if (bs_header_extra_2) {

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

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

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

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

  248.     } else {

  249.         sbr->bs_limiter_bands  = 2;

  250.         sbr->bs_limiter_gains  = 2;

  251.         sbr->bs_interpol_freq  = 1;

  252.         sbr->bs_smoothing_mode = 1;

  253.     }

  254. 

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

  256.         sbr_make_f_tablelim(sbr);

  257. 

  258.     return get_bits_count(gb) - cnt;

  259. }

  260. 

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

  262. {

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

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

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

  266.     return min;

  267. }

  268. 

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

  270. {

  271.     int k, previous, present;

  272.     float base, prod;

  273. 

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

  275.     prod = start;

  276.     previous = start;

  277. 

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

  279.         prod *= base;

  280.         present  = lrintf(prod);

  281.         bands[k] = present - previous;

  282.         previous = present;

  283.     }

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

  285. }

  286. 

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

  288. {

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

  290.     if (n_master <= 0) {

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

  292.         return -1;

  293.     }

  294.     if (bs_xover_band >= n_master) {

  295.         av_log(avctx, AV_LOG_ERROR,

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

  297.                bs_xover_band);

  298.         return -1;

  299.     }

  300.     return 0;

  301. }

  302. 

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

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

  305.                              SpectrumParameters *spectrum)

  306. {

  307.     unsigned int temp, max_qmf_subbands;

  308.     unsigned int start_min, stop_min;

  309.     int k;

  310.     const int8_t *sbr_offset_ptr;

  311.     int16_t stop_dk[13];

  312. 

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

  314.         temp = 3000;

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

  316.         temp = 4000;

  317.     } else

  318.         temp = 5000;

  319. 

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

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

  322. 

  323.     switch (sbr->sample_rate) {

  324.     case 16000:

  325.         sbr_offset_ptr = sbr_offset[0];

  326.         break;

  327.     case 22050:

  328.         sbr_offset_ptr = sbr_offset[1];

  329.         break;

  330.     case 24000:

  331.         sbr_offset_ptr = sbr_offset[2];

  332.         break;

  333.     case 32000:

  334.         sbr_offset_ptr = sbr_offset[3];

  335.         break;

  336.     case 44100: case 48000: case 64000:

  337.         sbr_offset_ptr = sbr_offset[4];

  338.         break;

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

  340.         sbr_offset_ptr = sbr_offset[5];

  341.         break;

  342.     default:

  343.         av_log(ac->avctx, AV_LOG_ERROR,

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

  345.         return -1;

  346.     }

  347. 

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

  349. 

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

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

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

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

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

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

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

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

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

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

  360.     } else {

  361.         av_log(ac->avctx, AV_LOG_ERROR,

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

  363.         return -1;

  364.     }

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

  366. 

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

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

  369.         max_qmf_subbands = 48;

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

  371.         max_qmf_subbands = 35;

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

  373.         max_qmf_subbands = 32;

  374. 

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

  376.         av_log(ac->avctx, AV_LOG_ERROR,

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

  378.         return -1;

  379.     }

  380. 

  381.     if (!spectrum->bs_freq_scale) {

  382.         int dk, k2diff;

  383. 

  384.         dk = spectrum->bs_alter_scale + 1;

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

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

  387.             return -1;

  388. 

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

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

  391. 

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

  393.         if (k2diff < 0) {

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

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

  396.         } else if (k2diff) {

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

  398.         }

  399. 

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

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

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

  403. 

  404.     } else {

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

  406.         int two_regions, num_bands_0;

  407.         int vdk0_max, vdk1_min;

  408.         int16_t vk0[49];

  409. 

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

  411.             two_regions = 1;

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

  413.         } else {

  414.             two_regions = 0;

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

  416.         }

  417. 

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

  419. 

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

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

  422.             return -1;

  423.         }

  424. 

  425.         vk0[0] = 0;

  426. 

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

  428. 

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

  430.         vdk0_max = vk0[num_bands_0];

  431. 

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

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

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

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

  436.                 return -1;

  437.             }

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

  439.         }

  440. 

  441.         if (two_regions) {

  442.             int16_t vk1[49];

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

  444.                                                      : 1.0f; // bs_alter_scale = {0,1}

  445.             int num_bands_1 = lrintf(half_bands * invwarp *

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

  447. 

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

  449. 

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

  451. 

  452.             if (vdk1_min < vdk0_max) {

  453.                 int change;

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

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

  456.                 vk1[1]           += change;

  457.                 vk1[num_bands_1] -= change;

  458.             }

  459. 

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

  461. 

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

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

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

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

  466.                     return -1;

  467.                 }

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

  469.             }

  470. 

  471.             sbr->n_master = num_bands_0 + num_bands_1;

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

  473.                 return -1;

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

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

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

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

  478. 

  479.         } else {

  480.             sbr->n_master = num_bands_0;

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

  482.                 return -1;

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

  484.         }

  485.     }

  486. 

  487.     return 0;

  488. }

  489. 

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

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

  492. {

  493.     int i, k, sb = 0;

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

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

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

  497. 

  498.     sbr->num_patches = 0;

  499. 

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

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

  502.     } else

  503.         k = sbr->n_master;

  504. 

  505.     do {

  506.         int odd = 0;

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

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

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

  510.         }

  511. 

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

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

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

  515.         // count of 6 patches

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

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

  518.             return -1;

  519.         }

  520. 

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

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

  523. 

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

  525.             usb = sb;

  526.             msb = sb;

  527.             sbr->num_patches++;

  528.         } else

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

  530. 

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

  532.             k = sbr->n_master;

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

  534. 

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

  536.         sbr->num_patches--;

  537. 

  538.     return 0;

  539. }

  540. 

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

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

  543. {

  544.     int k, temp;

  545. 

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

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

  548. 

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

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

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

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

  553. 

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

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

  556.         av_log(ac->avctx, AV_LOG_ERROR,

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

  558.         return -1;

  559.     }

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

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

  562.         return -1;

  563.     }

  564. 

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

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

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

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

  569. 

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

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

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

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

  574.         return -1;

  575.     }

  576. 

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

  578.     temp = 0;

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

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

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

  582.     }

  583. 

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

  585.         return -1;

  586. 

  587.     sbr_make_f_tablelim(sbr);

  588. 

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

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

  591. 

  592.     return 0;

  593. }

  594. 

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

  596.                                               int elements)

  597. {

  598.     int i;

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

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

  601.     }

  602. }

  603. 

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

  605. static const int8_t ceil_log2[] = {

  606.     0, 1, 2, 2, 3, 3,

  607. };

  608. 

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

  610.                          GetBitContext *gb, SBRData *ch_data)

  611. {

  612.     int i;

  613.     unsigned bs_pointer = 0;

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

  615.     int abs_bord_trail = 16;

  616.     int num_rel_lead, num_rel_trail;

  617.     unsigned bs_num_env_old = ch_data->bs_num_env;

  618. 

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

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

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

  622. 

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

  624.     case FIXFIX:

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

  626.         num_rel_lead                        = ch_data->bs_num_env - 1;

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

  628.             ch_data->bs_amp_res = 0;

  629. 

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

  631.             av_log(ac->avctx, AV_LOG_ERROR,

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

  633.                    ch_data->bs_num_env);

  634.             return -1;

  635.         }

  636. 

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

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

  639. 

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

  641.                    ch_data->bs_num_env;

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

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

  644. 

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

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

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

  648.         break;

  649.     case FIXVAR:

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

  651.         num_rel_trail                       = get_bits(gb, 2);

  652.         ch_data->bs_num_env                 = num_rel_trail + 1;

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

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

  655. 

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

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

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

  659. 

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

  661. 

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

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

  664.         break;

  665.     case VARFIX:

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

  667.         num_rel_lead                        = get_bits(gb, 2);

  668.         ch_data->bs_num_env                 = num_rel_lead + 1;

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

  670. 

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

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

  673. 

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

  675. 

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

  677.         break;

  678.     case VARVAR:

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

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

  681.         num_rel_lead                        = get_bits(gb, 2);

  682.         num_rel_trail                       = get_bits(gb, 2);

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

  684. 

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

  686.             av_log(ac->avctx, AV_LOG_ERROR,

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

  688.                    ch_data->bs_num_env);

  689.             return -1;

  690.         }

  691. 

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

  693. 

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

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

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

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

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

  699. 

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

  701. 

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

  703.         break;

  704.     }

  705. 

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

  707.         av_log(ac->avctx, AV_LOG_ERROR,

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

  709.                bs_pointer);

  710.         return -1;

  711.     }

  712. 

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

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

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

  716.             return -1;

  717.         }

  718.     }

  719. 

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

  721. 

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

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

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

  725.         unsigned int idx;

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

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

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

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

  730.         } else { // VARFIX

  731.             if (!bs_pointer)

  732.                 idx = 1;

  733.             else if (bs_pointer == 1)

  734.                 idx = ch_data->bs_num_env - 1;

  735.             else // bs_pointer > 1

  736.                 idx = bs_pointer - 1;

  737.         }

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

  739.     }

  740. 

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

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

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

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

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

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

  747. 

  748.     return 0;

  749. }

  750. 

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

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

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

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

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

  756. 

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

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

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

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

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

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

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

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

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

  766. }

  767. 

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

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

  770.                           SBRData *ch_data)

  771. {

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

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

  774. }

  775. 

  776. /// Read inverse filtering data

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

  778.                           SBRData *ch_data)

  779. {

  780.     int i;

  781. 

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

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

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

  785. }

  786. 

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

  788.                               SBRData *ch_data, int ch)

  789. {

  790.     int bits;

  791.     int i, j, k;

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

  793.     int t_lav, f_lav;

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

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

  796. 

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

  798.         if (ch_data->bs_amp_res) {

  799.             bits   = 5;

  800.             t_huff = vlc_sbr[T_HUFFMAN_ENV_BAL_3_0DB].table;

  801.             t_lav  = vlc_sbr_lav[T_HUFFMAN_ENV_BAL_3_0DB];

  802.             f_huff = vlc_sbr[F_HUFFMAN_ENV_BAL_3_0DB].table;

  803.             f_lav  = vlc_sbr_lav[F_HUFFMAN_ENV_BAL_3_0DB];

  804.         } else {

  805.             bits   = 6;

  806.             t_huff = vlc_sbr[T_HUFFMAN_ENV_BAL_1_5DB].table;

  807.             t_lav  = vlc_sbr_lav[T_HUFFMAN_ENV_BAL_1_5DB];

  808.             f_huff = vlc_sbr[F_HUFFMAN_ENV_BAL_1_5DB].table;

  809.             f_lav  = vlc_sbr_lav[F_HUFFMAN_ENV_BAL_1_5DB];

  810.         }

  811.     } else {

  812.         if (ch_data->bs_amp_res) {

  813.             bits   = 6;

  814.             t_huff = vlc_sbr[T_HUFFMAN_ENV_3_0DB].table;

  815.             t_lav  = vlc_sbr_lav[T_HUFFMAN_ENV_3_0DB];

  816.             f_huff = vlc_sbr[F_HUFFMAN_ENV_3_0DB].table;

  817.             f_lav  = vlc_sbr_lav[F_HUFFMAN_ENV_3_0DB];

  818.         } else {

  819.             bits   = 7;

  820.             t_huff = vlc_sbr[T_HUFFMAN_ENV_1_5DB].table;

  821.             t_lav  = vlc_sbr_lav[T_HUFFMAN_ENV_1_5DB];

  822.             f_huff = vlc_sbr[F_HUFFMAN_ENV_1_5DB].table;

  823.             f_lav  = vlc_sbr_lav[F_HUFFMAN_ENV_1_5DB];

  824.         }

  825.     }

  826. 

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

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

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

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

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

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

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

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

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

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

  837.                 }

  838.             } else {

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

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

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

  842.                 }

  843.             }

  844.         } else {

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

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

  847.                 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);

  848.         }

  849.     }

  850. 

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

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

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

  854. }

  855. 

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

  857.                            SBRData *ch_data, int ch)

  858. {

  859.     int i, j;

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

  861.     int t_lav, f_lav;

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

  863. 

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

  865.         t_huff = vlc_sbr[T_HUFFMAN_NOISE_BAL_3_0DB].table;

  866.         t_lav  = vlc_sbr_lav[T_HUFFMAN_NOISE_BAL_3_0DB];

  867.         f_huff = vlc_sbr[F_HUFFMAN_ENV_BAL_3_0DB].table;

  868.         f_lav  = vlc_sbr_lav[F_HUFFMAN_ENV_BAL_3_0DB];

  869.     } else {

  870.         t_huff = vlc_sbr[T_HUFFMAN_NOISE_3_0DB].table;

  871.         t_lav  = vlc_sbr_lav[T_HUFFMAN_NOISE_3_0DB];

  872.         f_huff = vlc_sbr[F_HUFFMAN_ENV_3_0DB].table;

  873.         f_lav  = vlc_sbr_lav[F_HUFFMAN_ENV_3_0DB];

  874.     }

  875. 

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

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

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

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

  880.         } else {

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

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

  883.                 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);

  884.         }

  885.     }

  886. 

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

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

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

  890. }

  891. 

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

  893.                                GetBitContext *gb,

  894.                                int bs_extension_id, int *num_bits_left)

  895. {

  896.     switch (bs_extension_id) {

  897.     case EXTENSION_ID_PS:

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

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

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

  901.             *num_bits_left = 0;

  902.         } else {

  903. #if 1

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

  905. #else

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

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

  908.             *num_bits_left = 0;

  909. #endif

  910.         }

  911.         break;

  912.     default:

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

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

  915.         *num_bits_left = 0;

  916.         break;

  917.     }

  918. }

  919. 

  920. static int read_sbr_single_channel_element(AACContext *ac,

  921.                                             SpectralBandReplication *sbr,

  922.                                             GetBitContext *gb)

  923. {

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

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

  926. 

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

  928.         return -1;

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

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

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

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

  933. 

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

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

  936. 

  937.     return 0;

  938. }

  939. 

  940. static int read_sbr_channel_pair_element(AACContext *ac,

  941.                                           SpectralBandReplication *sbr,

  942.                                           GetBitContext *gb)

  943. {

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

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

  946. 

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

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

  949.             return -1;

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

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

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

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

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

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

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

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

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

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

  960.     } else {

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

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

  963.             return -1;

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

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

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

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

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

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

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

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

  972.     }

  973. 

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

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

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

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

  978. 

  979.     return 0;

  980. }

  981. 

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

  983.                                   GetBitContext *gb, int id_aac)

  984. {

  985.     unsigned int cnt = get_bits_count(gb);

  986. 

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

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

  989.             sbr->start = 0;

  990.             return get_bits_count(gb) - cnt;

  991.         }

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

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

  994.             sbr->start = 0;

  995.             return get_bits_count(gb) - cnt;

  996.         }

  997.     } else {

  998.         av_log(ac->avctx, AV_LOG_ERROR,

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

  1000.         sbr->start = 0;

  1001.         return get_bits_count(gb) - cnt;

  1002.     }

  1003.     if (get_bits1(gb)) { // bs_extended_data

  1004.         int num_bits_left = get_bits(gb, 4); // bs_extension_size

  1005.         if (num_bits_left == 15)

  1006.             num_bits_left += get_bits(gb, 8); // bs_esc_count

  1007. 

  1008.         num_bits_left <<= 3;

  1009.         while (num_bits_left > 7) {

  1010.             num_bits_left -= 2;

  1011.             read_sbr_extension(ac, sbr, gb, get_bits(gb, 2), &num_bits_left); // bs_extension_id

  1012.         }

  1013.         if (num_bits_left < 0) {

  1014.             av_log(ac->avctx, AV_LOG_ERROR, "SBR Extension over read.\n");

  1015.         }

  1016.         if (num_bits_left > 0)

  1017.             skip_bits(gb, num_bits_left);

  1018.     }

  1019. 

  1020.     return get_bits_count(gb) - cnt;

  1021. }

  1022. 

  1023. static void sbr_reset(AACContext *ac, SpectralBandReplication *sbr)

  1024. {

  1025.     int err;

  1026.     err = sbr_make_f_master(ac, sbr, &sbr->spectrum_params);

  1027.     if (err >= 0)

  1028.         err = sbr_make_f_derived(ac, sbr);

  1029.     if (err < 0) {

  1030.         av_log(ac->avctx, AV_LOG_ERROR,

  1031.                "SBR reset failed. Switching SBR to pure upsampling mode.\n");

  1032.         sbr->start = 0;

  1033.     }

  1034. }

  1035. 

  1036. /**

  1037.  * Decode Spectral Band Replication extension data; reference: table 4.55.

  1038.  *

  1039.  * @param   crc flag indicating the presence of CRC checksum

  1040.  * @param   cnt length of TYPE_FIL syntactic element in bytes

  1041.  *

  1042.  * @return  Returns number of bytes consumed from the TYPE_FIL element.

  1043.  */

  1044. int ff_decode_sbr_extension(AACContext *ac, SpectralBandReplication *sbr,

  1045.                             GetBitContext *gb_host, int crc, int cnt, int id_aac)

  1046. {

  1047.     unsigned int num_sbr_bits = 0, num_align_bits;

  1048.     unsigned bytes_read;

  1049.     GetBitContext gbc = *gb_host, *gb = &gbc;

  1050.     skip_bits_long(gb_host, cnt*8 - 4);

  1051. 

  1052.     sbr->reset = 0;

  1053. 

  1054.     if (!sbr->sample_rate)

  1055.         sbr->sample_rate = 2 * ac->m4ac.sample_rate; //TODO use the nominal sample rate for arbitrary sample rate support

  1056.     if (!ac->m4ac.ext_sample_rate)

  1057.         ac->m4ac.ext_sample_rate = 2 * ac->m4ac.sample_rate;

  1058. 

  1059.     if (crc) {

  1060.         skip_bits(gb, 10); // bs_sbr_crc_bits; TODO - implement CRC check

  1061.         num_sbr_bits += 10;

  1062.     }

  1063. 

  1064.     //Save some state from the previous frame.

  1065.     sbr->kx[0] = sbr->kx[1];

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

  1067. 

  1068.     num_sbr_bits++;

  1069.     if (get_bits1(gb)) // bs_header_flag

  1070.         num_sbr_bits += read_sbr_header(sbr, gb);

  1071. 

  1072.     if (sbr->reset)

  1073.         sbr_reset(ac, sbr);

  1074. 

  1075.     if (sbr->start)

  1076.         num_sbr_bits  += read_sbr_data(ac, sbr, gb, id_aac);

  1077. 

  1078.     num_align_bits = ((cnt << 3) - 4 - num_sbr_bits) & 7;

  1079.     bytes_read = ((num_sbr_bits + num_align_bits + 4) >> 3);

  1080. 

  1081.     if (bytes_read > cnt) {

  1082.         av_log(ac->avctx, AV_LOG_ERROR,

  1083.                "Expected to read %d SBR bytes actually read %d.\n", cnt, bytes_read);

  1084.     }

  1085.     return cnt;

  1086. }

  1087. 

  1088. /// Dequantization and stereo decoding (14496-3 sp04 p203)

  1089. static void sbr_dequant(SpectralBandReplication *sbr, int id_aac)

  1090. {

  1091.     int k, e;

  1092.     int ch;

  1093. 

  1094.     if (id_aac == TYPE_CPE && sbr->bs_coupling) {

  1095.         float alpha      = sbr->data[0].bs_amp_res ?  1.0f :  0.5f;

  1096.         float pan_offset = sbr->data[0].bs_amp_res ? 12.0f : 24.0f;

  1097.         for (e = 1; e <= sbr->data[0].bs_num_env; e++) {

  1098.             for (k = 0; k < sbr->n[sbr->data[0].bs_freq_res[e]]; k++) {

  1099.                 float temp1 = exp2f(sbr->data[0].env_facs[e][k] * alpha + 7.0f);

  1100.                 float temp2 = exp2f((pan_offset - sbr->data[1].env_facs[e][k]) * alpha);

  1101.                 float fac   = temp1 / (1.0f + temp2);

  1102.                 sbr->data[0].env_facs[e][k] = fac;

  1103.                 sbr->data[1].env_facs[e][k] = fac * temp2;

  1104.             }

  1105.         }

  1106.         for (e = 1; e <= sbr->data[0].bs_num_noise; e++) {

  1107.             for (k = 0; k < sbr->n_q; k++) {

  1108.                 float temp1 = exp2f(NOISE_FLOOR_OFFSET - sbr->data[0].noise_facs[e][k] + 1);

  1109.                 float temp2 = exp2f(12 - sbr->data[1].noise_facs[e][k]);

  1110.                 float fac   = temp1 / (1.0f + temp2);

  1111.                 sbr->data[0].noise_facs[e][k] = fac;

  1112.                 sbr->data[1].noise_facs[e][k] = fac * temp2;

  1113.             }

  1114.         }

  1115.     } else { // SCE or one non-coupled CPE

  1116.         for (ch = 0; ch < (id_aac == TYPE_CPE) + 1; ch++) {

  1117.             float alpha = sbr->data[ch].bs_amp_res ? 1.0f : 0.5f;

  1118.             for (e = 1; e <= sbr->data[ch].bs_num_env; e++)

  1119.                 for (k = 0; k < sbr->n[sbr->data[ch].bs_freq_res[e]]; k++)

  1120.                     sbr->data[ch].env_facs[e][k] =

  1121.                         exp2f(alpha * sbr->data[ch].env_facs[e][k] + 6.0f);

  1122.             for (e = 1; e <= sbr->data[ch].bs_num_noise; e++)

  1123.                 for (k = 0; k < sbr->n_q; k++)

  1124.                     sbr->data[ch].noise_facs[e][k] =

  1125.                         exp2f(NOISE_FLOOR_OFFSET - sbr->data[ch].noise_facs[e][k]);

  1126.         }

  1127.     }

  1128. }

  1129. 

  1130. /**

  1131.  * Analysis QMF Bank (14496-3 sp04 p206)

  1132.  *

  1133.  * @param   x       pointer to the beginning of the first sample window

  1134.  * @param   W       array of complex-valued samples split into subbands

  1135.  */

  1136. static void sbr_qmf_analysis(DSPContext *dsp, FFTContext *mdct, const float *in, float *x,

  1137.                              float z[320], float W[2][32][32][2],

  1138.                              float scale)

  1139. {

  1140.     int i, k;

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

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

  1143.     if (scale != 1.0f)

  1144.         dsp->vector_fmul_scalar(x+288, in, scale, 1024);

  1145.     else

  1146.         memcpy(x+288, in, 1024*sizeof(*x));

  1147.     for (i = 0; i < 32; i++) { // numTimeSlots*RATE = 16*2 as 960 sample frames

  1148.                                // are not supported

  1149.         dsp->vector_fmul_reverse(z, sbr_qmf_window_ds, x, 320);

  1150.         for (k = 0; k < 64; k++) {

  1151.             float f = z[k] + z[k + 64] + z[k + 128] + z[k + 192] + z[k + 256];

  1152.             z[k] = f;

  1153.         }

  1154.         //Shuffle to IMDCT

  1155.         z[64] = z[0];

  1156.         for (k = 1; k < 32; k++) {

  1157.             z[64+2*k-1] =  z[   k];

  1158.             z[64+2*k  ] = -z[64-k];

  1159.         }

  1160.         z[64+63] = z[32];

  1161. 

  1162.         ff_imdct_half(mdct, z, z+64);

  1163.         for (k = 0; k < 32; k++) {

  1164.             W[1][i][k][0] = -z[63-k];

  1165.             W[1][i][k][1] = z[k];

  1166.         }

  1167.         x += 32;

  1168.     }

  1169. }

  1170. 

  1171. /**

  1172.  * Synthesis QMF Bank (14496-3 sp04 p206) and Downsampled Synthesis QMF Bank

  1173.  * (14496-3 sp04 p206)

  1174.  */

  1175. static void sbr_qmf_synthesis(DSPContext *dsp, FFTContext *mdct,

  1176.                               float *out, float X[2][38][64],

  1177.                               float mdct_buf[2][64],

  1178.                               float *v0, int *v_off, const unsigned int div,

  1179.                               float bias, float scale)

  1180. {

  1181.     int i, n;

  1182.     const float *sbr_qmf_window = div ? sbr_qmf_window_ds : sbr_qmf_window_us;

  1183.     int scale_and_bias = scale != 1.0f || bias != 0.0f;

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

  1209.             ff_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.         if (scale_and_bias)

  1226.             for (n = 0; n < 64 >> div; n++)

  1227.                 out[n] = out[n] * scale + bias;

  1228.         out += 64 >> div;

  1229.     }

  1230. }

  1231. 

  1232. static void autocorrelate(const float x[40][2], float phi[3][2][2], int lag)

  1233. {

  1234.     int i;

  1235.     float real_sum = 0.0f;

  1236.     float imag_sum = 0.0f;

  1237.     if (lag) {

  1238.         for (i = 1; i < 38; i++) {

  1239.             real_sum += x[i][0] * x[i+lag][0] + x[i][1] * x[i+lag][1];

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

  1241.         }

  1242.         phi[2-lag][1][0] = real_sum + x[ 0][0] * x[lag][0] + x[ 0][1] * x[lag][1];

  1243.         phi[2-lag][1][1] = imag_sum + x[ 0][0] * x[lag][1] - x[ 0][1] * x[lag][0];

  1244.         if (lag == 1) {

  1245.             phi[0][0][0] = real_sum + x[38][0] * x[39][0] + x[38][1] * x[39][1];

  1246.             phi[0][0][1] = imag_sum + x[38][0] * x[39][1] - x[38][1] * x[39][0];

  1247.         }

  1248.     } else {

  1249.         for (i = 1; i < 38; i++) {

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

  1251.         }

  1252.         phi[2][1][0] = real_sum + x[ 0][0] * x[ 0][0] + x[ 0][1] * x[ 0][1];

  1253.         phi[1][0][0] = real_sum + x[38][0] * x[38][0] + x[38][1] * x[38][1];

  1254.     }

  1255. }

  1256. 

  1257. /** High Frequency Generation (14496-3 sp04 p214+) and Inverse Filtering

  1258.  * (14496-3 sp04 p214)

  1259.  * Warning: This routine does not seem numerically stable.

  1260.  */

  1261. static void sbr_hf_inverse_filter(float (*alpha0)[2], float (*alpha1)[2],

  1262.                                   const float X_low[32][40][2], int k0)

  1263. {

  1264.     int k;

  1265.     for (k = 0; k < k0; k++) {

  1266.         float phi[3][2][2], dk;

  1267. 

  1268.         autocorrelate(X_low[k], phi, 0);

  1269.         autocorrelate(X_low[k], phi, 1);

  1270.         autocorrelate(X_low[k], phi, 2);

  1271. 

  1272.         dk =  phi[2][1][0] * phi[1][0][0] -

  1273.              (phi[1][1][0] * phi[1][1][0] + phi[1][1][1] * phi[1][1][1]) / 1.000001f;

  1274. 

  1275.         if (!dk) {

  1276.             alpha1[k][0] = 0;

  1277.             alpha1[k][1] = 0;

  1278.         } else {

  1279.             float temp_real, temp_im;

  1280.             temp_real = phi[0][0][0] * phi[1][1][0] -

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

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

  1283.             temp_im   = phi[0][0][0] * phi[1][1][1] +

  1284.                         phi[0][0][1] * phi[1][1][0] -

  1285.                         phi[0][1][1] * phi[1][0][0];

  1286. 

  1287.             alpha1[k][0] = temp_real / dk;

  1288.             alpha1[k][1] = temp_im   / dk;

  1289.         }

  1290. 

  1291.         if (!phi[1][0][0]) {

  1292.             alpha0[k][0] = 0;

  1293.             alpha0[k][1] = 0;

  1294.         } else {

  1295.             float temp_real, temp_im;

  1296.             temp_real = phi[0][0][0] + alpha1[k][0] * phi[1][1][0] +

  1297.                                        alpha1[k][1] * phi[1][1][1];

  1298.             temp_im   = phi[0][0][1] + alpha1[k][1] * phi[1][1][0] -

  1299.                                        alpha1[k][0] * phi[1][1][1];

  1300. 

  1301.             alpha0[k][0] = -temp_real / phi[1][0][0];

  1302.             alpha0[k][1] = -temp_im   / phi[1][0][0];

  1303.         }

  1304. 

  1305.         if (alpha1[k][0] * alpha1[k][0] + alpha1[k][1] * alpha1[k][1] >= 16.0f ||

  1306.            alpha0[k][0] * alpha0[k][0] + alpha0[k][1] * alpha0[k][1] >= 16.0f) {

  1307.             alpha1[k][0] = 0;

  1308.             alpha1[k][1] = 0;

  1309.             alpha0[k][0] = 0;

  1310.             alpha0[k][1] = 0;

  1311.         }

  1312.     }

  1313. }

  1314. 

  1315. /// Chirp Factors (14496-3 sp04 p214)

  1316. static void sbr_chirp(SpectralBandReplication *sbr, SBRData *ch_data)

  1317. {

  1318.     int i;

  1319.     float new_bw;

  1320.     static const float bw_tab[] = { 0.0f, 0.75f, 0.9f, 0.98f };

  1321. 

  1322.     for (i = 0; i < sbr->n_q; i++) {

  1323.         if (ch_data->bs_invf_mode[0][i] + ch_data->bs_invf_mode[1][i] == 1) {

  1324.             new_bw = 0.6f;

  1325.         } else

  1326.             new_bw = bw_tab[ch_data->bs_invf_mode[0][i]];

  1327. 

  1328.         if (new_bw < ch_data->bw_array[i]) {

  1329.             new_bw = 0.75f    * new_bw + 0.25f    * ch_data->bw_array[i];

  1330.         } else

  1331.             new_bw = 0.90625f * new_bw + 0.09375f * ch_data->bw_array[i];

  1332.         ch_data->bw_array[i] = new_bw < 0.015625f ? 0.0f : new_bw;

  1333.     }

  1334. }

  1335. 

  1336. /// Generate the subband filtered lowband

  1337. static int sbr_lf_gen(AACContext *ac, SpectralBandReplication *sbr,

  1338.                       float X_low[32][40][2], const float W[2][32][32][2])

  1339. {

  1340.     int i, k;

  1341.     const int t_HFGen = 8;

  1342.     const int i_f = 32;

  1343.     memset(X_low, 0, 32*sizeof(*X_low));

  1344.     for (k = 0; k < sbr->kx[1]; k++) {

  1345.         for (i = t_HFGen; i < i_f + t_HFGen; i++) {

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

  1347.             X_low[k][i][1] = W[1][i - t_HFGen][k][1];

  1348.         }

  1349.     }

  1350.     for (k = 0; k < sbr->kx[0]; k++) {

  1351.         for (i = 0; i < t_HFGen; i++) {

  1352.             X_low[k][i][0] = W[0][i + i_f - t_HFGen][k][0];

  1353.             X_low[k][i][1] = W[0][i + i_f - t_HFGen][k][1];

  1354.         }

  1355.     }

  1356.     return 0;

  1357. }

  1358. 

  1359. /// High Frequency Generator (14496-3 sp04 p215)

  1360. static int sbr_hf_gen(AACContext *ac, SpectralBandReplication *sbr,

  1361.                       float X_high[64][40][2], const float X_low[32][40][2],

  1362.                       const float (*alpha0)[2], const float (*alpha1)[2],

  1363.                       const float bw_array[5], const uint8_t *t_env,

  1364.                       int bs_num_env)

  1365. {

  1366.     int i, j, x;

  1367.     int g = 0;

  1368.     int k = sbr->kx[1];

  1369.     for (j = 0; j < sbr->num_patches; j++) {

  1370.         for (x = 0; x < sbr->patch_num_subbands[j]; x++, k++) {

  1371.             float alpha[4];

  1372.             const int p = sbr->patch_start_subband[j] + x;

  1373.             while (g <= sbr->n_q && k >= sbr->f_tablenoise[g])

  1374.                 g++;

  1375.             g--;

  1376. 

  1377.             if (g < 0) {

  1378.                 av_log(ac->avctx, AV_LOG_ERROR,

  1379.                        "ERROR : no subband found for frequency %d\n", k);

  1380.                 return -1;

  1381.             }

  1382. 

  1383.             alpha[0] = alpha1[p][0] * bw_array[g] * bw_array[g];

  1384.             alpha[1] = alpha1[p][1] * bw_array[g] * bw_array[g];

  1385.             alpha[2] = alpha0[p][0] * bw_array[g];

  1386.             alpha[3] = alpha0[p][1] * bw_array[g];

  1387. 

  1388.             for (i = 2 * t_env[0]; i < 2 * t_env[bs_num_env]; i++) {

  1389.                 const int idx = i + ENVELOPE_ADJUSTMENT_OFFSET;

  1390.                 X_high[k][idx][0] =

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

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

  1393.                     X_low[p][idx - 1][0] * alpha[2] -

  1394.                     X_low[p][idx - 1][1] * alpha[3] +

  1395.                     X_low[p][idx][0];

  1396.                 X_high[k][idx][1] =

  1397.                     X_low[p][idx - 2][1] * alpha[0] +

  1398.                     X_low[p][idx - 2][0] * alpha[1] +

  1399.                     X_low[p][idx - 1][1] * alpha[2] +

  1400.                     X_low[p][idx - 1][0] * alpha[3] +

  1401.                     X_low[p][idx][1];

  1402.             }

  1403.         }

  1404.     }

  1405.     if (k < sbr->m[1] + sbr->kx[1])

  1406.         memset(X_high + k, 0, (sbr->m[1] + sbr->kx[1] - k) * sizeof(*X_high));

  1407. 

  1408.     return 0;

  1409. }

  1410. 

  1411. /// Generate the subband filtered lowband

  1412. static int sbr_x_gen(SpectralBandReplication *sbr, float X[2][38][64],

  1413.                      const float X_low[32][40][2], const float Y[2][38][64][2],

  1414.                      int ch)

  1415. {

  1416.     int k, i;

  1417.     const int i_f = 32;

  1418.     const int i_Temp = FFMAX(2*sbr->data[ch].t_env_num_env_old - i_f, 0);

  1419.     memset(X, 0, 2*sizeof(*X));

  1420.     for (k = 0; k < sbr->kx[0]; k++) {

  1421.         for (i = 0; i < i_Temp; i++) {

  1422.             X[0][i][k] = X_low[k][i + ENVELOPE_ADJUSTMENT_OFFSET][0];

  1423.             X[1][i][k] = X_low[k][i + ENVELOPE_ADJUSTMENT_OFFSET][1];

  1424.         }

  1425.     }

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

  1427.         for (i = 0; i < i_Temp; i++) {

  1428.             X[0][i][k] = Y[0][i + i_f][k][0];

  1429.             X[1][i][k] = Y[0][i + i_f][k][1];

  1430.         }

  1431.     }

  1432. 

  1433.     for (k = 0; k < sbr->kx[1]; k++) {

  1434.         for (i = i_Temp; i < 38; i++) {

  1435.             X[0][i][k] = X_low[k][i + ENVELOPE_ADJUSTMENT_OFFSET][0];

  1436.             X[1][i][k] = X_low[k][i + ENVELOPE_ADJUSTMENT_OFFSET][1];

  1437.         }

  1438.     }

  1439.     for (; k < sbr->kx[1] + sbr->m[1]; k++) {

  1440.         for (i = i_Temp; i < i_f; i++) {

  1441.             X[0][i][k] = Y[1][i][k][0];

  1442.             X[1][i][k] = Y[1][i][k][1];

  1443.         }

  1444.     }

  1445.     return 0;

  1446. }

  1447. 

  1448. /** High Frequency Adjustment (14496-3 sp04 p217) and Mapping

  1449.  * (14496-3 sp04 p217)

  1450.  */

  1451. static void sbr_mapping(AACContext *ac, SpectralBandReplication *sbr,

  1452.                         SBRData *ch_data, int e_a[2])

  1453. {

  1454.     int e, i, m;

  1455. 

  1456.     memset(ch_data->s_indexmapped[1], 0, 7*sizeof(ch_data->s_indexmapped[1]));

  1457.     for (e = 0; e < ch_data->bs_num_env; e++) {

  1458.         const unsigned int ilim = sbr->n[ch_data->bs_freq_res[e + 1]];

  1459.         uint16_t *table = ch_data->bs_freq_res[e + 1] ? sbr->f_tablehigh : sbr->f_tablelow;

  1460.         int k;

  1461. 

  1462.         for (i = 0; i < ilim; i++)

  1463.             for (m = table[i]; m < table[i + 1]; m++)

  1464.                 sbr->e_origmapped[e][m - sbr->kx[1]] = ch_data->env_facs[e+1][i];

  1465. 

  1466.         // ch_data->bs_num_noise > 1 => 2 noise floors

  1467.         k = (ch_data->bs_num_noise > 1) && (ch_data->t_env[e] >= ch_data->t_q[1]);

  1468.         for (i = 0; i < sbr->n_q; i++)

  1469.             for (m = sbr->f_tablenoise[i]; m < sbr->f_tablenoise[i + 1]; m++)

  1470.                 sbr->q_mapped[e][m - sbr->kx[1]] = ch_data->noise_facs[k+1][i];

  1471. 

  1472.         for (i = 0; i < sbr->n[1]; i++) {

  1473.             if (ch_data->bs_add_harmonic_flag) {

  1474.                 const unsigned int m_midpoint =

  1475.                     (sbr->f_tablehigh[i] + sbr->f_tablehigh[i + 1]) >> 1;

  1476. 

  1477.                 ch_data->s_indexmapped[e + 1][m_midpoint - sbr->kx[1]] = ch_data->bs_add_harmonic[i] *

  1478.                     (e >= e_a[1] || (ch_data->s_indexmapped[0][m_midpoint - sbr->kx[1]] == 1));

  1479.             }

  1480.         }

  1481. 

  1482.         for (i = 0; i < ilim; i++) {

  1483.             int additional_sinusoid_present = 0;

  1484.             for (m = table[i]; m < table[i + 1]; m++) {

  1485.                 if (ch_data->s_indexmapped[e + 1][m - sbr->kx[1]]) {

  1486.                     additional_sinusoid_present = 1;

  1487.                     break;

  1488.                 }

  1489.             }

  1490.             memset(&sbr->s_mapped[e][table[i] - sbr->kx[1]], additional_sinusoid_present,

  1491.                    (table[i + 1] - table[i]) * sizeof(sbr->s_mapped[e][0]));

  1492.         }

  1493.     }

  1494. 

  1495.     memcpy(ch_data->s_indexmapped[0], ch_data->s_indexmapped[ch_data->bs_num_env], sizeof(ch_data->s_indexmapped[0]));

  1496. }

  1497. 

  1498. /// Estimation of current envelope (14496-3 sp04 p218)

  1499. static void sbr_env_estimate(float (*e_curr)[48], float X_high[64][40][2],

  1500.                              SpectralBandReplication *sbr, SBRData *ch_data)

  1501. {

  1502.     int e, i, m;

  1503. 

  1504.     if (sbr->bs_interpol_freq) {

  1505.         for (e = 0; e < ch_data->bs_num_env; e++) {

  1506.             const float recip_env_size = 0.5f / (ch_data->t_env[e + 1] - ch_data->t_env[e]);

  1507.             int ilb = ch_data->t_env[e]     * 2 + ENVELOPE_ADJUSTMENT_OFFSET;

  1508.             int iub = ch_data->t_env[e + 1] * 2 + ENVELOPE_ADJUSTMENT_OFFSET;

  1509. 

  1510.             for (m = 0; m < sbr->m[1]; m++) {

  1511.                 float sum = 0.0f;

  1512. 

  1513.                 for (i = ilb; i < iub; i++) {

  1514.                     sum += X_high[m + sbr->kx[1]][i][0] * X_high[m + sbr->kx[1]][i][0] +

  1515.                            X_high[m + sbr->kx[1]][i][1] * X_high[m + sbr->kx[1]][i][1];

  1516.                 }

  1517.                 e_curr[e][m] = sum * recip_env_size;

  1518.             }

  1519.         }

  1520.     } else {

  1521.         int k, p;

  1522. 

  1523.         for (e = 0; e < ch_data->bs_num_env; e++) {

  1524.             const int env_size = 2 * (ch_data->t_env[e + 1] - ch_data->t_env[e]);

  1525.             int ilb = ch_data->t_env[e]     * 2 + ENVELOPE_ADJUSTMENT_OFFSET;

  1526.             int iub = ch_data->t_env[e + 1] * 2 + ENVELOPE_ADJUSTMENT_OFFSET;

  1527.             const uint16_t *table = ch_data->bs_freq_res[e + 1] ? sbr->f_tablehigh : sbr->f_tablelow;

  1528. 

  1529.             for (p = 0; p < sbr->n[ch_data->bs_freq_res[e + 1]]; p++) {

  1530.                 float sum = 0.0f;

  1531.                 const int den = env_size * (table[p + 1] - table[p]);

  1532. 

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

  1534.                     for (i = ilb; i < iub; i++) {

  1535.                         sum += X_high[k][i][0] * X_high[k][i][0] +

  1536.                                X_high[k][i][1] * X_high[k][i][1];

  1537.                     }

  1538.                 }

  1539.                 sum /= den;

  1540.                 for (k = table[p]; k < table[p + 1]; k++) {

  1541.                     e_curr[e][k - sbr->kx[1]] = sum;

  1542.                 }

  1543.             }

  1544.         }

  1545.     }

  1546. }

  1547. 

  1548. /**

  1549.  * Calculation of levels of additional HF signal components (14496-3 sp04 p219)

  1550.  * and Calculation of gain (14496-3 sp04 p219)

  1551.  */

  1552. static void sbr_gain_calc(AACContext *ac, SpectralBandReplication *sbr,

  1553.                           SBRData *ch_data, const int e_a[2])

  1554. {

  1555.     int e, k, m;

  1556.     // max gain limits : -3dB, 0dB, 3dB, inf dB (limiter off)

  1557.     static const float limgain[4] = { 0.70795, 1.0, 1.41254, 10000000000 };

  1558. 

  1559.     for (e = 0; e < ch_data->bs_num_env; e++) {

  1560.         int delta = !((e == e_a[1]) || (e == e_a[0]));

  1561.         for (k = 0; k < sbr->n_lim; k++) {

  1562.             float gain_boost, gain_max;

  1563.             float sum[2] = { 0.0f, 0.0f };

  1564.             for (m = sbr->f_tablelim[k] - sbr->kx[1]; m < sbr->f_tablelim[k + 1] - sbr->kx[1]; m++) {

  1565.                 const float temp = sbr->e_origmapped[e][m] / (1.0f + sbr->q_mapped[e][m]);

  1566.                 sbr->q_m[e][m] = sqrtf(temp * sbr->q_mapped[e][m]);

  1567.                 sbr->s_m[e][m] = sqrtf(temp * ch_data->s_indexmapped[e + 1][m]);

  1568.                 if (!sbr->s_mapped[e][m]) {

  1569.                     sbr->gain[e][m] = sqrtf(sbr->e_origmapped[e][m] /

  1570.                                             ((1.0f + sbr->e_curr[e][m]) *

  1571.                                              (1.0f + sbr->q_mapped[e][m] * delta)));

  1572.                 } else {

  1573.                     sbr->gain[e][m] = sqrtf(sbr->e_origmapped[e][m] * sbr->q_mapped[e][m] /

  1574.                                             ((1.0f + sbr->e_curr[e][m]) *

  1575.                                              (1.0f + sbr->q_mapped[e][m])));

  1576.                 }

  1577.             }

  1578.             for (m = sbr->f_tablelim[k] - sbr->kx[1]; m < sbr->f_tablelim[k + 1] - sbr->kx[1]; m++) {

  1579.                 sum[0] += sbr->e_origmapped[e][m];

  1580.                 sum[1] += sbr->e_curr[e][m];

  1581.             }

  1582.             gain_max = limgain[sbr->bs_limiter_gains] * sqrtf((FLT_EPSILON + sum[0]) / (FLT_EPSILON + sum[1]));

  1583.             gain_max = FFMIN(100000, gain_max);

  1584.             for (m = sbr->f_tablelim[k] - sbr->kx[1]; m < sbr->f_tablelim[k + 1] - sbr->kx[1]; m++) {

  1585.                 float q_m_max   = sbr->q_m[e][m] * gain_max / sbr->gain[e][m];

  1586.                 sbr->q_m[e][m]  = FFMIN(sbr->q_m[e][m], q_m_max);

  1587.                 sbr->gain[e][m] = FFMIN(sbr->gain[e][m], gain_max);

  1588.             }

  1589.             sum[0] = sum[1] = 0.0f;

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

  1591.                 sum[0] += sbr->e_origmapped[e][m];

  1592.                 sum[1] += sbr->e_curr[e][m] * sbr->gain[e][m] * sbr->gain[e][m]

  1593.                           + sbr->s_m[e][m] * sbr->s_m[e][m]

  1594.                           + (delta && !sbr->s_m[e][m]) * sbr->q_m[e][m] * sbr->q_m[e][m];

  1595.             }

  1596.             gain_boost = sqrtf((FLT_EPSILON + sum[0]) / (FLT_EPSILON + sum[1]));

  1597.             gain_boost = FFMIN(1.584893192, gain_boost);

  1598.             for (m = sbr->f_tablelim[k] - sbr->kx[1]; m < sbr->f_tablelim[k + 1] - sbr->kx[1]; m++) {

  1599.                 sbr->gain[e][m] *= gain_boost;

  1600.                 sbr->q_m[e][m]  *= gain_boost;

  1601.                 sbr->s_m[e][m]  *= gain_boost;

  1602.             }

  1603.         }

  1604.     }

  1605. }

  1606. 

  1607. /// Assembling HF Signals (14496-3 sp04 p220)

  1608. static void sbr_hf_assemble(float Y[2][38][64][2], const float X_high[64][40][2],

  1609.                             SpectralBandReplication *sbr, SBRData *ch_data,

  1610.                             const int e_a[2])

  1611. {

  1612.     int e, i, j, m;

  1613.     const int h_SL = 4 * !sbr->bs_smoothing_mode;

  1614.     const int kx = sbr->kx[1];

  1615.     const int m_max = sbr->m[1];

  1616.     static const float h_smooth[5] = {

  1617.         0.33333333333333,

  1618.         0.30150283239582,

  1619.         0.21816949906249,

  1620.         0.11516383427084,

  1621.         0.03183050093751,

  1622.     };

  1623.     static const int8_t phi[2][4] = {

  1624.         {  1,  0, -1,  0}, // real

  1625.         {  0,  1,  0, -1}, // imaginary

  1626.     };

  1627.     float (*g_temp)[48] = ch_data->g_temp, (*q_temp)[48] = ch_data->q_temp;

  1628.     int indexnoise = ch_data->f_indexnoise;

  1629.     int indexsine  = ch_data->f_indexsine;

  1630.     memcpy(Y[0], Y[1], sizeof(Y[0]));

  1631. 

  1632.     if (sbr->reset) {

  1633.         for (i = 0; i < h_SL; i++) {

  1634.             memcpy(g_temp[i + 2*ch_data->t_env[0]], sbr->gain[0], m_max * sizeof(sbr->gain[0][0]));

  1635.             memcpy(q_temp[i + 2*ch_data->t_env[0]], sbr->q_m[0],  m_max * sizeof(sbr->q_m[0][0]));

  1636.         }

  1637.     } else if (h_SL) {

  1638.         memcpy(g_temp[2*ch_data->t_env[0]], g_temp[2*ch_data->t_env_num_env_old], 4*sizeof(g_temp[0]));

  1639.         memcpy(q_temp[2*ch_data->t_env[0]], q_temp[2*ch_data->t_env_num_env_old], 4*sizeof(q_temp[0]));

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

  1645.             memcpy(q_temp[h_SL + i], sbr->q_m[e],  m_max * sizeof(sbr->q_m[0][0]));

  1646.         }

  1647.     }

  1648. 

  1649.     for (e = 0; e < ch_data->bs_num_env; e++) {

  1650.         for (i = 2 * ch_data->t_env[e]; i < 2 * ch_data->t_env[e + 1]; i++) {

  1651.             int phi_sign = (1 - 2*(kx & 1));

  1652. 

  1653.             if (h_SL && e != e_a[0] && e != e_a[1]) {

  1654.                 for (m = 0; m < m_max; m++) {

  1655.                     const int idx1 = i + h_SL;

  1656.                     float g_filt = 0.0f;

  1657.                     for (j = 0; j <= h_SL; j++)

  1658.                         g_filt += g_temp[idx1 - j][m] * h_smooth[j];

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

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

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

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

  1663.                 }

  1664.             } else {

  1665.                 for (m = 0; m < m_max; m++) {

  1666.                     const float g_filt = g_temp[i + h_SL][m];

  1667.                     Y[1][i][m + kx][0] =

  1668.                         X_high[m + kx][i + ENVELOPE_ADJUSTMENT_OFFSET][0] * g_filt;

  1669.                     Y[1][i][m + kx][1] =

  1670.                         X_high[m + kx][i + ENVELOPE_ADJUSTMENT_OFFSET][1] * g_filt;

  1671.                 }

  1672.             }

  1673. 

  1674.             if (e != e_a[0] && e != e_a[1]) {

  1675.                 for (m = 0; m < m_max; m++) {

  1676.                     indexnoise = (indexnoise + 1) & 0x1ff;

  1677.                     if (sbr->s_m[e][m]) {

  1678.                         Y[1][i][m + kx][0] +=

  1679.                             sbr->s_m[e][m] * phi[0][indexsine];

  1680.                         Y[1][i][m + kx][1] +=

  1681.                             sbr->s_m[e][m] * (phi[1][indexsine] * phi_sign);

  1682.                     } else {

  1683.                         float q_filt;

  1684.                         if (h_SL) {

  1685.                             const int idx1 = i + h_SL;

  1686.                             q_filt = 0.0f;

  1687.                             for (j = 0; j <= h_SL; j++)

  1688.                                 q_filt += q_temp[idx1 - j][m] * h_smooth[j];

  1689.                         } else {

  1690.                             q_filt = q_temp[i][m];

  1691.                         }

  1692.                         Y[1][i][m + kx][0] +=

  1693.                             q_filt * sbr_noise_table[indexnoise][0];

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

  1695.                             q_filt * sbr_noise_table[indexnoise][1];

  1696.                     }

  1697.                     phi_sign = -phi_sign;

  1698.                 }

  1699.             } else {

  1700.                 indexnoise = (indexnoise + m_max) & 0x1ff;

  1701.                 for (m = 0; m < m_max; m++) {

  1702.                     Y[1][i][m + kx][0] +=

  1703.                         sbr->s_m[e][m] * phi[0][indexsine];

  1704.                     Y[1][i][m + kx][1] +=

  1705.                         sbr->s_m[e][m] * (phi[1][indexsine] * phi_sign);

  1706.                     phi_sign = -phi_sign;

  1707.                 }

  1708.             }

  1709.             indexsine = (indexsine + 1) & 3;

  1710.         }

  1711.     }

  1712.     ch_data->f_indexnoise = indexnoise;

  1713.     ch_data->f_indexsine  = indexsine;

  1714. }

  1715. 

  1716. void ff_sbr_apply(AACContext *ac, SpectralBandReplication *sbr, int id_aac,

  1717.                   float* L, float* R)

  1718. {

  1719.     int downsampled = ac->m4ac.ext_sample_rate < sbr->sample_rate;

  1720.     int ch;

  1721.     int nch = (id_aac == TYPE_CPE) ? 2 : 1;

  1722. 

  1723.     if (sbr->start) {

  1724.         sbr_dequant(sbr, id_aac);

  1725.     }

  1726.     for (ch = 0; ch < nch; ch++) {

  1727.         /* decode channel */

  1728.         sbr_qmf_analysis(&ac->dsp, &sbr->mdct_ana, ch ? R : L, sbr->data[ch].analysis_filterbank_samples,

  1729.                          (float*)sbr->qmf_filter_scratch,

  1730.                          sbr->data[ch].W, 1/(-1024 * ac->sf_scale));

  1731.         sbr_lf_gen(ac, sbr, sbr->X_low, sbr->data[ch].W);

  1732.         if (sbr->start) {

  1733.             sbr_hf_inverse_filter(sbr->alpha0, sbr->alpha1, sbr->X_low, sbr->k[0]);

  1734.             sbr_chirp(sbr, &sbr->data[ch]);

  1735.             sbr_hf_gen(ac, sbr, sbr->X_high, sbr->X_low, sbr->alpha0, sbr->alpha1,

  1736.                        sbr->data[ch].bw_array, sbr->data[ch].t_env,

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

  1738. 

  1739.             // hf_adj

  1740.             sbr_mapping(ac, sbr, &sbr->data[ch], sbr->data[ch].e_a);

  1741.             sbr_env_estimate(sbr->e_curr, sbr->X_high, sbr, &sbr->data[ch]);

  1742.             sbr_gain_calc(ac, sbr, &sbr->data[ch], sbr->data[ch].e_a);

  1743.             sbr_hf_assemble(sbr->data[ch].Y, sbr->X_high, sbr, &sbr->data[ch],

  1744.                             sbr->data[ch].e_a);

  1745.         }

  1746. 

  1747.         /* synthesis */

  1748.         sbr_x_gen(sbr, sbr->X[ch], sbr->X_low, sbr->data[ch].Y, ch);

  1749.     }

  1750. 

  1751.     if (ac->m4ac.ps == 1) {

  1752.         if (sbr->ps.start) {

  1753.             ff_ps_apply(ac->avctx, &sbr->ps, sbr->X[0], sbr->X[1], sbr->kx[1] + sbr->m[1]);

  1754.         } else {

  1755.             memcpy(sbr->X[1], sbr->X[0], sizeof(sbr->X[0]));

  1756.         }

  1757.         nch = 2;

  1758.     }

  1759. 

  1760.     sbr_qmf_synthesis(&ac->dsp, &sbr->mdct, L, sbr->X[0], sbr->qmf_filter_scratch,

  1761.                       sbr->data[0].synthesis_filterbank_samples,

  1762.                       &sbr->data[0].synthesis_filterbank_samples_offset,

  1763.                       downsampled,

  1764.                       ac->add_bias, -1024 * ac->sf_scale);

  1765.     if (nch == 2)

  1766.         sbr_qmf_synthesis(&ac->dsp, &sbr->mdct, R, sbr->X[1], sbr->qmf_filter_scratch,

  1767.                           sbr->data[1].synthesis_filterbank_samples,

  1768.                           &sbr->data[1].synthesis_filterbank_samples_offset,

  1769.                           downsampled,

  1770.                           ac->add_bias, -1024 * ac->sf_scale);

  1771. }