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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 libavcodec/aacsbr.c

  25.  * AAC Spectral Band Replication decoding functions

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

  27.  */

  28. 

  29. #include "aac.h"

  30. #include "sbr.h"

  31. #include "aacsbr.h"

  32. #include "aacsbrdata.h"

  33. #include "fft.h"

  34. 

  35. #include <stdint.h>

  36. #include <float.h>

  37. 

  38. #define ENVELOPE_ADJUSTMENT_OFFSET 2

  39. #define NOISE_FLOOR_OFFSET 6.0f

  40. 

  41. /**

  42.  * SBR VLC tables

  43.  */

  44. enum {

  45.     T_HUFFMAN_ENV_1_5DB,

  46.     F_HUFFMAN_ENV_1_5DB,

  47.     T_HUFFMAN_ENV_BAL_1_5DB,

  48.     F_HUFFMAN_ENV_BAL_1_5DB,

  49.     T_HUFFMAN_ENV_3_0DB,

  50.     F_HUFFMAN_ENV_3_0DB,

  51.     T_HUFFMAN_ENV_BAL_3_0DB,

  52.     F_HUFFMAN_ENV_BAL_3_0DB,

  53.     T_HUFFMAN_NOISE_3_0DB,

  54.     T_HUFFMAN_NOISE_BAL_3_0DB,

  55. };

  56. 

  57. /**

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

  59.  */

  60. enum {

  61.     FIXFIX,

  62.     FIXVAR,

  63.     VARFIX,

  64.     VARVAR,

  65. };

  66. 

  67. enum {

  68.     EXTENSION_ID_PS = 2,

  69. };

  70. 

  71. static VLC vlc_sbr[10];

  72. static const int8_t vlc_sbr_lav[10] =

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

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

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

  76. static DECLARE_ALIGNED(16, float, analysis_cossin_post)[32][2];

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

  78. 

  79. #define SBR_INIT_VLC_STATIC(num, size) \

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

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

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

  83.                     size)

  84. 

  85. #define SBR_VLC_ROW(name) \

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

  87. 

  88. av_cold void ff_aac_sbr_init(void)

  89. {

  90.     int n, k;

  91.     static const struct {

  92.         const void *sbr_codes, *sbr_bits;

  93.         const unsigned int table_size, elem_size;

  94.     } sbr_tmp[] = {

  95.         SBR_VLC_ROW(t_huffman_env_1_5dB),

  96.         SBR_VLC_ROW(f_huffman_env_1_5dB),

  97.         SBR_VLC_ROW(t_huffman_env_bal_1_5dB),

  98.         SBR_VLC_ROW(f_huffman_env_bal_1_5dB),

  99.         SBR_VLC_ROW(t_huffman_env_3_0dB),

  100.         SBR_VLC_ROW(f_huffman_env_3_0dB),

  101.         SBR_VLC_ROW(t_huffman_env_bal_3_0dB),

  102.         SBR_VLC_ROW(f_huffman_env_bal_3_0dB),

  103.         SBR_VLC_ROW(t_huffman_noise_3_0dB),

  104.         SBR_VLC_ROW(t_huffman_noise_bal_3_0dB),

  105.     };

  106. 

  107.     // SBR VLC table initialization

  108.     SBR_INIT_VLC_STATIC(0, 1098);

  109.     SBR_INIT_VLC_STATIC(1, 1092);

  110.     SBR_INIT_VLC_STATIC(2, 768);

  111.     SBR_INIT_VLC_STATIC(3, 1026);

  112.     SBR_INIT_VLC_STATIC(4, 1058);

  113.     SBR_INIT_VLC_STATIC(5, 1052);

  114.     SBR_INIT_VLC_STATIC(6, 544);

  115.     SBR_INIT_VLC_STATIC(7, 544);

  116.     SBR_INIT_VLC_STATIC(8, 592);

  117.     SBR_INIT_VLC_STATIC(9, 512);

  118. 

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

  120.         float pre = M_PI * n / 64;

  121.         analysis_cos_pre[n] = cosf(pre);

  122.         analysis_sin_pre[n] = sinf(pre);

  123.     }

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

  125.         float post = M_PI * (k + 0.5) / 128;

  126.         analysis_cossin_post[k][0] =  4.0 * cosf(post);

  127.         analysis_cossin_post[k][1] = -4.0 * sinf(post);

  128.     }

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

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

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

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

  133. 

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

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

  136. }

  137. 

  138. av_cold void ff_aac_sbr_ctx_init(SpectralBandReplication *sbr)

  139. {

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

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

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

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

  144.     ff_rdft_init(&sbr->rdft, 6, IDFT_R2C);

  145. }

  146. 

  147. av_cold void ff_aac_sbr_ctx_close(SpectralBandReplication *sbr)

  148. {

  149.     ff_mdct_end(&sbr->mdct);

  150.     ff_rdft_end(&sbr->rdft);

  151. }

  152. 

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

  154. {

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

  156. }

  157. 

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

  159. {

  160.     int i;

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

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

  163.             return 1;

  164.     return 0;

  165. }

  166. 

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

  168. static void sbr_make_f_tablelim(SpectralBandReplication *sbr)

  169. {

  170.     int k;

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

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

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

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

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

  176.         int16_t patch_borders[5];

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

  178. 

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

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

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

  182. 

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

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

  185.         if (sbr->num_patches > 1)

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

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

  188. 

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

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

  191.               qsort_comparison_function_int16);

  192. 

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

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

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

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

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

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

  199.                 in++;

  200.                 sbr->n_lim--;

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

  202.                 *out = *in++;

  203.                 sbr->n_lim--;

  204.             } else {

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

  206.             }

  207.         }

  208.     } else {

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

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

  211.         sbr->n_lim = 1;

  212.     }

  213. }

  214. 

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

  216. {

  217.     unsigned int cnt = get_bits_count(gb);

  218.     uint8_t bs_header_extra_1;

  219.     uint8_t bs_header_extra_2;

  220.     int old_bs_limiter_bands = sbr->bs_limiter_bands;

  221.     SpectrumParameters old_spectrum_params;

  222. 

  223.     sbr->start = 1;

  224. 

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

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

  227. 

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

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

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

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

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

  233. 

  234.     bs_header_extra_1 = get_bits1(gb);

  235.     bs_header_extra_2 = get_bits1(gb);

  236. 

  237.     if (bs_header_extra_1) {

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

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

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

  241.     } else {

  242.         sbr->spectrum_params.bs_freq_scale  = 2;

  243.         sbr->spectrum_params.bs_alter_scale = 1;

  244.         sbr->spectrum_params.bs_noise_bands = 2;

  245.     }

  246. 

  247.     // Check if spectrum parameters changed

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

  249.         sbr->reset = 1;

  250. 

  251.     if (bs_header_extra_2) {

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

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

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

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

  256.     } else {

  257.         sbr->bs_limiter_bands  = 2;

  258.         sbr->bs_limiter_gains  = 2;

  259.         sbr->bs_interpol_freq  = 1;

  260.         sbr->bs_smoothing_mode = 1;

  261.     }

  262. 

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

  264.         sbr_make_f_tablelim(sbr);

  265. 

  266.     return get_bits_count(gb) - cnt;

  267. }

  268. 

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

  270. {

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

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

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

  274.     return min;

  275. }

  276. 

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

  278. {

  279.     int k, previous, present;

  280.     float base, prod;

  281. 

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

  283.     prod = start;

  284.     previous = start;

  285. 

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

  287.         prod *= base;

  288.         present  = lrintf(prod);

  289.         bands[k] = present - previous;

  290.         previous = present;

  291.     }

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

  293. }

  294. 

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

  296. {

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

  298.     if (n_master <= 0) {

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

  300.         return -1;

  301.     }

  302.     if (bs_xover_band >= n_master) {

  303.         av_log(avccontext, AV_LOG_ERROR,

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

  305.                bs_xover_band);

  306.         return -1;

  307.     }

  308.     return 0;

  309. }

  310. 

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

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

  313.                              SpectrumParameters *spectrum)

  314. {

  315.     unsigned int temp, max_qmf_subbands;

  316.     unsigned int start_min, stop_min;

  317.     int k;

  318.     const int8_t *sbr_offset_ptr;

  319.     int16_t stop_dk[13];

  320. 

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

  322.         temp = 3000;

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

  324.         temp = 4000;

  325.     } else

  326.         temp = 5000;

  327. 

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

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

  330. 

  331.     switch (sbr->sample_rate) {

  332.     case 16000:

  333.         sbr_offset_ptr = sbr_offset[0];

  334.         break;

  335.     case 22050:

  336.         sbr_offset_ptr = sbr_offset[1];

  337.         break;

  338.     case 24000:

  339.         sbr_offset_ptr = sbr_offset[2];

  340.         break;

  341.     case 32000:

  342.         sbr_offset_ptr = sbr_offset[3];

  343.         break;

  344.     case 44100: case 48000: case 64000:

  345.         sbr_offset_ptr = sbr_offset[4];

  346.         break;

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

  348.         sbr_offset_ptr = sbr_offset[5];

  349.         break;

  350.     default:

  351.         av_log(ac->avccontext, AV_LOG_ERROR,

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

  353.         return -1;

  354.     }

  355. 

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

  357. 

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

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

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

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

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

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

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

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

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

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

  368.     } else {

  369.         av_log(ac->avccontext, AV_LOG_ERROR,

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

  371.         return -1;

  372.     }

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

  374. 

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

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

  377.         max_qmf_subbands = 48;

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

  379.         max_qmf_subbands = 35;

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

  381.         max_qmf_subbands = 32;

  382. 

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

  384.         av_log(ac->avccontext, AV_LOG_ERROR,

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

  386.         return -1;

  387.     }

  388. 

  389.     if (!spectrum->bs_freq_scale) {

  390.         unsigned int dk;

  391.         int k2diff;

  392. 

  393.         dk = spectrum->bs_alter_scale + 1;

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

  395.         if (check_n_master(ac->avccontext, sbr->n_master, sbr->spectrum_params.bs_xover_band))

  396.             return -1;

  397. 

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

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

  400. 

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

  402.         if (k2diff < 0) {

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

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

  405.         } else if (k2diff) {

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

  407.         }

  408. 

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

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

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

  412. 

  413.     } else {

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

  415.         int two_regions, num_bands_0;

  416.         int vdk0_max, vdk1_min;

  417.         int16_t vk0[49];

  418. 

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

  420.             two_regions = 1;

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

  422.         } else {

  423.             two_regions = 0;

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

  425.         }

  426. 

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

  428. 

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

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

  431.             return -1;

  432.         }

  433. 

  434.         vk0[0] = 0;

  435. 

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

  437. 

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

  439.         vdk0_max = vk0[num_bands_0];

  440. 

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

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

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

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

  445.                 return -1;

  446.             }

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

  448.         }

  449. 

  450.         if (two_regions) {

  451.             int16_t vk1[49];

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

  453.                                                      : 1.0f; // bs_alter_scale = {0,1}

  454.             int num_bands_1 = lrintf(half_bands * invwarp *

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

  456. 

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

  458. 

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

  460. 

  461.             if (vdk1_min < vdk0_max) {

  462.                 int change;

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

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

  465.                 vk1[1]           += change;

  466.                 vk1[num_bands_1] -= change;

  467.             }

  468. 

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

  470. 

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

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

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

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

  475.                     return -1;

  476.                 }

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

  478.             }

  479. 

  480.             sbr->n_master = num_bands_0 + num_bands_1;

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

  482.                 return -1;

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

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

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

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

  487. 

  488.         } else {

  489.             sbr->n_master = num_bands_0;

  490.             if (check_n_master(ac->avccontext, sbr->n_master, sbr->spectrum_params.bs_xover_band))

  491.                 return -1;

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

  493.         }

  494.     }

  495. 

  496.     return 0;

  497. }

  498. 

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

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

  501. {

  502.     int i, k, sb = 0;

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

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

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

  506. 

  507.     sbr->num_patches = 0;

  508. 

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

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

  511.     } else

  512.         k = sbr->n_master;

  513. 

  514.     do {

  515.         int odd = 0;

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

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

  518.             odd = (sb + sbr->k[0]) & 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.     // Requirements (14496-3 sp04 p205) sets the maximum number of patches to 5

  539.     // However the Coding Technologies decoder check uses 6 patches

  540.     if (sbr->num_patches > 6) {

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

  542.         return -1;

  543.     }

  544. 

  545.     return 0;

  546. }

  547. 

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

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

  550. {

  551.     int k, temp;

  552. 

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

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

  555. 

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

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

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

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

  560. 

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

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

  563.         av_log(ac->avccontext, AV_LOG_ERROR,

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

  565.         return -1;

  566.     }

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

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

  569.         return -1;

  570.     }

  571. 

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

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

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

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

  576. 

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

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

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

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

  581.         return -1;

  582.     }

  583. 

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

  585.     temp = 0;

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

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

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

  589.     }

  590. 

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

  592.         return -1;

  593. 

  594.     sbr_make_f_tablelim(sbr);

  595. 

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

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

  598. 

  599.     return 0;

  600. }

  601. 

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

  603.                                               int elements)

  604. {

  605.     int i;

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

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

  608.     }

  609. }

  610. 

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

  612. static const int8_t ceil_log2[] = {

  613.     0, 1, 2, 2, 3, 3,

  614. };

  615. 

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

  617.                          GetBitContext *gb, SBRData *ch_data)

  618. {

  619.     int i;

  620. 

  621.     ch_data->bs_freq_res[0] = ch_data->bs_freq_res[ch_data->bs_num_env[1]];

  622.     ch_data->bs_num_env[0] = ch_data->bs_num_env[1];

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

  624. 

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

  626.     case FIXFIX:

  627.         ch_data->bs_num_env[1] = 1 << get_bits(gb, 2);

  628.         if (ch_data->bs_num_env[1] == 1)

  629.             ch_data->bs_amp_res = 0;

  630. 

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

  632.         for (i = 1; i < ch_data->bs_num_env[1]; i++)

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

  634.         break;

  635.     case FIXVAR:

  636.         ch_data->bs_var_bord[1] = get_bits(gb, 2);

  637.         ch_data->bs_num_rel[1]  = get_bits(gb, 2);

  638.         ch_data->bs_num_env[1]  = ch_data->bs_num_rel[1] + 1;

  639. 

  640.         for (i = 0; i < ch_data->bs_num_rel[1]; i++)

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

  642. 

  643.         ch_data->bs_pointer = get_bits(gb, ceil_log2[ch_data->bs_num_env[1]]);

  644. 

  645.         for (i = 0; i < ch_data->bs_num_env[1]; i++)

  646.             ch_data->bs_freq_res[ch_data->bs_num_env[1] - i] = get_bits1(gb);

  647.         break;

  648.     case VARFIX:

  649.         ch_data->bs_var_bord[0] = get_bits(gb, 2);

  650.         ch_data->bs_num_rel[0]  = get_bits(gb, 2);

  651.         ch_data->bs_num_env[1]  = ch_data->bs_num_rel[0] + 1;

  652. 

  653.         for (i = 0; i < ch_data->bs_num_rel[0]; i++)

  654.             ch_data->bs_rel_bord[0][i] = 2 * get_bits(gb, 2) + 2;

  655. 

  656.         ch_data->bs_pointer = get_bits(gb, ceil_log2[ch_data->bs_num_env[1]]);

  657. 

  658.         get_bits1_vector(gb, ch_data->bs_freq_res + 1, ch_data->bs_num_env[1]);

  659.         break;

  660.     case VARVAR:

  661.         ch_data->bs_var_bord[0] = get_bits(gb, 2);

  662.         ch_data->bs_var_bord[1] = get_bits(gb, 2);

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

  664.         ch_data->bs_num_rel[1]  = get_bits(gb, 2);

  665.         ch_data->bs_num_env[1]  = ch_data->bs_num_rel[0] + ch_data->bs_num_rel[1] + 1;

  666. 

  667.         for (i = 0; i < ch_data->bs_num_rel[0]; i++)

  668.             ch_data->bs_rel_bord[0][i] = 2 * get_bits(gb, 2) + 2;

  669.         for (i = 0; i < ch_data->bs_num_rel[1]; i++)

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

  671. 

  672.         ch_data->bs_pointer = get_bits(gb, ceil_log2[ch_data->bs_num_env[1]]);

  673. 

  674.         get_bits1_vector(gb, ch_data->bs_freq_res + 1, ch_data->bs_num_env[1]);

  675.         break;

  676.     }

  677. 

  678.     if (ch_data->bs_frame_class == FIXFIX && ch_data->bs_num_env[1] > 4) {

  679.         av_log(ac->avccontext, AV_LOG_ERROR,

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

  681.                ch_data->bs_num_env[1]);

  682.         return -1;

  683.     }

  684.     if (ch_data->bs_frame_class == VARVAR && ch_data->bs_num_env[1] > 5) {

  685.         av_log(ac->avccontext, AV_LOG_ERROR,

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

  687.                ch_data->bs_num_env[1]);

  688.         return -1;

  689.     }

  690. 

  691.     ch_data->bs_num_noise = (ch_data->bs_num_env[1] > 1) + 1;

  692. 

  693.     return 0;

  694. }

  695. 

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

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

  698.     dst->bs_freq_res[0] = dst->bs_freq_res[dst->bs_num_env[1]];

  699.     dst->bs_num_env[0]  = dst->bs_num_env[1];

  700. 

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

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

  703.     memcpy(dst->bs_num_env+1,  src->bs_num_env+1,  sizeof(dst->bs_num_env)- sizeof(*dst->bs_num_env));

  704.     memcpy(dst->bs_var_bord,   src->bs_var_bord,   sizeof(dst->bs_var_bord));

  705.     memcpy(dst->bs_rel_bord,   src->bs_rel_bord,   sizeof(dst->bs_rel_bord));

  706.     memcpy(dst->bs_num_rel,    src->bs_num_rel,    sizeof(dst->bs_rel_bord));

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

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

  709.     dst->bs_pointer     = src->bs_pointer;

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

  711. }

  712. 

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

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

  715.                           SBRData *ch_data)

  716. {

  717.     get_bits1_vector(gb, ch_data->bs_df_env,   ch_data->bs_num_env[1]);

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

  719. }

  720. 

  721. /// Read inverse filtering data

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

  723.                           SBRData *ch_data)

  724. {

  725.     int i;

  726. 

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

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

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

  730. }

  731. 

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

  733.                               SBRData *ch_data, int ch)

  734. {

  735.     int bits;

  736.     int i, j, k;

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

  738.     int t_lav, f_lav;

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

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

  741. 

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

  743.         if (ch_data->bs_amp_res) {

  744.             bits   = 5;

  745.             t_huff = vlc_sbr[T_HUFFMAN_ENV_BAL_3_0DB].table;

  746.             t_lav  = vlc_sbr_lav[T_HUFFMAN_ENV_BAL_3_0DB];

  747.             f_huff = vlc_sbr[F_HUFFMAN_ENV_BAL_3_0DB].table;

  748.             f_lav  = vlc_sbr_lav[F_HUFFMAN_ENV_BAL_3_0DB];

  749.         } else {

  750.             bits   = 6;

  751.             t_huff = vlc_sbr[T_HUFFMAN_ENV_BAL_1_5DB].table;

  752.             t_lav  = vlc_sbr_lav[T_HUFFMAN_ENV_BAL_1_5DB];

  753.             f_huff = vlc_sbr[F_HUFFMAN_ENV_BAL_1_5DB].table;

  754.             f_lav  = vlc_sbr_lav[F_HUFFMAN_ENV_BAL_1_5DB];

  755.         }

  756.     } else {

  757.         if (ch_data->bs_amp_res) {

  758.             bits   = 6;

  759.             t_huff = vlc_sbr[T_HUFFMAN_ENV_3_0DB].table;

  760.             t_lav  = vlc_sbr_lav[T_HUFFMAN_ENV_3_0DB];

  761.             f_huff = vlc_sbr[F_HUFFMAN_ENV_3_0DB].table;

  762.             f_lav  = vlc_sbr_lav[F_HUFFMAN_ENV_3_0DB];

  763.         } else {

  764.             bits   = 7;

  765.             t_huff = vlc_sbr[T_HUFFMAN_ENV_1_5DB].table;

  766.             t_lav  = vlc_sbr_lav[T_HUFFMAN_ENV_1_5DB];

  767.             f_huff = vlc_sbr[F_HUFFMAN_ENV_1_5DB].table;

  768.             f_lav  = vlc_sbr_lav[F_HUFFMAN_ENV_1_5DB];

  769.         }

  770.     }

  771. 

  772.     for (i = 0; i < ch_data->bs_num_env[1]; i++) {

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

  774.             // bs_freq_res[0] == bs_freq_res[bs_num_env[1]] from prev frame

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

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

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

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

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

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

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

  782.                 }

  783.             } else {

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

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

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

  787.                 }

  788.             }

  789.         } else {

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

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

  792.                 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);

  793.         }

  794.     }

  795. 

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

  797.     memcpy(ch_data->env_facs[0], ch_data->env_facs[ch_data->bs_num_env[1]],

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

  799. }

  800. 

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

  802.                            SBRData *ch_data, int ch)

  803. {

  804.     int i, j;

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

  806.     int t_lav, f_lav;

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

  808. 

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

  810.         t_huff = vlc_sbr[T_HUFFMAN_NOISE_BAL_3_0DB].table;

  811.         t_lav  = vlc_sbr_lav[T_HUFFMAN_NOISE_BAL_3_0DB];

  812.         f_huff = vlc_sbr[F_HUFFMAN_ENV_BAL_3_0DB].table;

  813.         f_lav  = vlc_sbr_lav[F_HUFFMAN_ENV_BAL_3_0DB];

  814.     } else {

  815.         t_huff = vlc_sbr[T_HUFFMAN_NOISE_3_0DB].table;

  816.         t_lav  = vlc_sbr_lav[T_HUFFMAN_NOISE_3_0DB];

  817.         f_huff = vlc_sbr[F_HUFFMAN_ENV_3_0DB].table;

  818.         f_lav  = vlc_sbr_lav[F_HUFFMAN_ENV_3_0DB];

  819.     }

  820. 

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

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

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

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

  825.         } else {

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

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

  828.                 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);

  829.         }

  830.     }

  831. 

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

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

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

  835. }

  836. 

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

  838.                                GetBitContext *gb,

  839.                           int bs_extension_id, int *num_bits_left)

  840. {

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

  842.     switch (bs_extension_id) {

  843.     case EXTENSION_ID_PS:

  844. #if 0

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

  846. #else

  847.         av_log_missing_feature(ac->avccontext, "Parametric Stereo is", 0);

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

  849.         *num_bits_left = 0;

  850. #endif

  851.         break;

  852.     default:

  853.         av_log_missing_feature(ac->avccontext, "Reserved SBR extensions are", 1);

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

  855.         *num_bits_left = 0;

  856.         break;

  857.     }

  858. }

  859. 

  860. static int read_sbr_single_channel_element(AACContext *ac,

  861.                                             SpectralBandReplication *sbr,

  862.                                             GetBitContext *gb)

  863. {

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

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

  866. 

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

  868.         return -1;

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

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

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

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

  873. 

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

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

  876. 

  877.     return 0;

  878. }

  879. 

  880. static int read_sbr_channel_pair_element(AACContext *ac,

  881.                                           SpectralBandReplication *sbr,

  882.                                           GetBitContext *gb)

  883. {

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

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

  886. 

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

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

  889.             return -1;

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

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

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

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

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

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

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

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

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

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

  900.     } else {

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

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

  903.             return -1;

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

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

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

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

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

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

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

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

  912.     }

  913. 

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

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

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

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

  918. 

  919.     return 0;

  920. }

  921. 

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

  923.                                   GetBitContext *gb, int id_aac)

  924. {

  925.     unsigned int cnt = get_bits_count(gb);

  926. 

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

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

  929.             sbr->start = 0;

  930.             return get_bits_count(gb) - cnt;

  931.         }

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

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

  934.             sbr->start = 0;

  935.             return get_bits_count(gb) - cnt;

  936.         }

  937.     } else {

  938.         av_log(ac->avccontext, AV_LOG_ERROR,

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

  940.         sbr->start = 0;

  941.         return get_bits_count(gb) - cnt;

  942.     }

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

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

  945.         if (num_bits_left == 15)

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

  947. 

  948.         num_bits_left <<= 3;

  949.         while (num_bits_left > 7) {

  950.             num_bits_left -= 2;

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

  952.         }

  953.     }

  954. 

  955.     return get_bits_count(gb) - cnt;

  956. }

  957. 

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

  959. {

  960.     int err;

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

  962.     if (err >= 0)

  963.         err = sbr_make_f_derived(ac, sbr);

  964.     if (err < 0) {

  965.         av_log(ac->avccontext, AV_LOG_ERROR,

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

  967.         sbr->start = 0;

  968.     }

  969. }

  970. 

  971. /**

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

  973.  *

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

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

  976.  *

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

  978.  */

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

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

  981. {

  982.     unsigned int num_sbr_bits = 0, num_align_bits;

  983.     unsigned bytes_read;

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

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

  986. 

  987.     sbr->reset = 0;

  988. 

  989.     if (!sbr->sample_rate)

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

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

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

  993. 

  994.     if (crc) {

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

  996.         num_sbr_bits += 10;

  997.     }

  998. 

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

  1000.     sbr->kx[0] = sbr->kx[1];

  1001.     sbr->m[0] = sbr->m[1];

  1002. 

  1003.     num_sbr_bits++;

  1004.     if (get_bits1(gb)) // bs_header_flag

  1005.         num_sbr_bits += read_sbr_header(sbr, gb);

  1006. 

  1007.     if (sbr->reset)

  1008.         sbr_reset(ac, sbr);

  1009. 

  1010.     if (sbr->start)

  1011.         num_sbr_bits  += read_sbr_data(ac, sbr, gb, id_aac);

  1012. 

  1013.     num_align_bits = ((cnt << 3) - 4 - num_sbr_bits) & 7;

  1014.     bytes_read = ((num_sbr_bits + num_align_bits + 4) >> 3);

  1015. 

  1016.     if (bytes_read > cnt) {

  1017.         av_log(ac->avccontext, AV_LOG_ERROR,

  1018.                "Expected to read %d SBR bytes actually read %d.\n", cnt, bytes_read);

  1019.     }

  1020.     return cnt;

  1021. }

  1022. 

  1023. /// Time/frequency Grid (14496-3 sp04 p200)

  1024. static int sbr_time_freq_grid(AACContext *ac, SpectralBandReplication *sbr,

  1025.                               SBRData *ch_data, int ch)

  1026. {

  1027.     int abs_bord_lead  =  ch_data->bs_frame_class >= 2 ? ch_data->bs_var_bord[0] : 0;

  1028.     // frameLengthFlag ? 15 : 16; 960 sample length frames unsupported; this value is numTimeSlots

  1029.     int abs_bord_trail = (ch_data->bs_frame_class & 1 ? ch_data->bs_var_bord[1] : 0) + 16;

  1030.     int n_rel_lead;

  1031.     int i;

  1032. 

  1033.     if (ch_data->bs_frame_class == FIXFIX) {

  1034.         n_rel_lead = ch_data->bs_num_env[1] - 1;

  1035.     } else if (ch_data->bs_frame_class == FIXVAR) {

  1036.         n_rel_lead = 0;

  1037.     } else if (ch_data->bs_frame_class < 4) { // VARFIX or VARVAR

  1038.         n_rel_lead = ch_data->bs_num_rel[0];

  1039.     } else {

  1040.         av_log(ac->avccontext, AV_LOG_ERROR,

  1041.                "Invalid bs_frame_class for SBR: %d\n", ch_data->bs_frame_class);

  1042.         return -1;

  1043.     }

  1044. 

  1045.     ch_data->t_env_num_env_old = ch_data->t_env[ch_data->bs_num_env[0]];

  1046.     ch_data->t_env[0]                      = abs_bord_lead;

  1047.     ch_data->t_env[ch_data->bs_num_env[1]] = abs_bord_trail;

  1048. 

  1049.     if (ch_data->bs_frame_class == FIXFIX) {

  1050.         int temp = (abs_bord_trail + (ch_data->bs_num_env[1] >> 1)) /

  1051.                    ch_data->bs_num_env[1];

  1052.         for (i = 0; i < n_rel_lead; i++)

  1053.             ch_data->t_env[i + 1] = ch_data->t_env[i] + temp;

  1054.     } else if (ch_data->bs_frame_class > 1) { // VARFIX or VARVAR

  1055.         for (i = 0; i < n_rel_lead; i++)

  1056.             ch_data->t_env[i + 1] = ch_data->t_env[i] + ch_data->bs_rel_bord[0][i];

  1057.     } else { // FIXVAR

  1058.         for (i = 0; i < n_rel_lead; i++)

  1059.             ch_data->t_env[i + 1] = abs_bord_lead;

  1060.     }

  1061. 

  1062.     if (ch_data->bs_frame_class & 1) { // FIXVAR or VARVAR

  1063.         for (i = ch_data->bs_num_env[1] - 1; i > n_rel_lead; i--)

  1064.             ch_data->t_env[i] = ch_data->t_env[i + 1] -

  1065.                                 ch_data->bs_rel_bord[1][ch_data->bs_num_env[1] - 1 - i];

  1066.     } else { // FIXFIX or VARFIX

  1067.         for (i = n_rel_lead; i < ch_data->bs_num_env[1]; i++)

  1068.             ch_data->t_env[i + 1] = abs_bord_trail;

  1069.     }

  1070. 

  1071.     ch_data->t_q[0] = ch_data->t_env[0];

  1072.     if (ch_data->bs_num_noise > 1) { // typo in spec bases this on bs_num_env...

  1073.         unsigned int idx;

  1074.         if (ch_data->bs_frame_class == FIXFIX) {

  1075.             idx = ch_data->bs_num_env[1] >> 1;

  1076.         } else if (ch_data->bs_frame_class & 1) { // FIXVAR or VARVAR

  1077.             idx = ch_data->bs_num_env[1] - FFMAX(ch_data->bs_pointer - 1, 1);

  1078.         } else { // VARFIX

  1079.             if (!ch_data->bs_pointer)

  1080.                 idx = 1;

  1081.             else if (ch_data->bs_pointer == 1)

  1082.                 idx = ch_data->bs_num_env[1] - 1;

  1083.             else // bs_pointer > 1

  1084.                 idx = ch_data->bs_pointer - 1;

  1085.         }

  1086.         ch_data->t_q[1] = ch_data->t_env[idx];

  1087.         ch_data->t_q[2] = ch_data->t_env[ch_data->bs_num_env[1]];

  1088.     } else

  1089.         ch_data->t_q[1] = ch_data->t_env[ch_data->bs_num_env[1]];

  1090. 

  1091.     return 0;

  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[1]; 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[1]; 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, RDFTContext *rdft, const float *in, float *x,

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

  1144.                              float bias, float scale)

  1145. {

  1146.     int i, k;

  1147.     memcpy(W[0], W[1], sizeof(W[0]));

  1148.     memcpy(x    , x+1024, (320-32)*sizeof(x[0]));

  1149.     if (scale != 1.0f || bias != 0.0f)

  1150.         for (i = 0; i < 1024; i++)

  1151.             x[288 + i] = (in[i] - bias) * scale;

  1152.     else

  1153.         memcpy(x+288, in, 1024*sizeof(*x));

  1154.     for (i = 0; i < 32; i++) { // numTimeSlots*RATE = 16*2 as 960 sample frames

  1155.                                // are not supported

  1156.         float re, im;

  1157.         dsp->vector_fmul_reverse(z, sbr_qmf_window_ds, x, 320);

  1158.         for (k = 0; k < 64; k++) {

  1159.             float f = z[k] + z[k + 64] + z[k + 128] + z[k + 192] + z[k + 256];

  1160.             z[k] = f * analysis_cos_pre[k];

  1161.             z[k+64] = f;

  1162.         }

  1163.         ff_rdft_calc(rdft, z);

  1164.         re = z[0] * 0.5f;

  1165.         im = 0.5f * dsp->scalarproduct_float(z+64, analysis_sin_pre, 64);

  1166.         W[1][i][0][0] = re * analysis_cossin_post[0][0] - im * analysis_cossin_post[0][1];

  1167.         W[1][i][0][1] = re * analysis_cossin_post[0][1] + im * analysis_cossin_post[0][0];

  1168.         for (k = 1; k < 32; k++) {

  1169.             re = z[2*k  ] - re;

  1170.             im = z[2*k+1] - im;

  1171.             W[1][i][k][0] = re * analysis_cossin_post[k][0] - im * analysis_cossin_post[k][1];

  1172.             W[1][i][k][1] = re * analysis_cossin_post[k][1] + im * analysis_cossin_post[k][0];

  1173.         }

  1174.         x += 32;

  1175.     }

  1176. }

  1177. 

  1178. /**

  1179.  * Synthesis QMF Bank (14496-3 sp04 p206) and Downsampled Synthesis QMF Bank

  1180.  * (14496-3 sp04 p206)

  1181.  */

  1182. static void sbr_qmf_synthesis(DSPContext *dsp, FFTContext *mdct,

  1183.                               float *out, float X[2][32][64],

  1184.                               float mdct_buf[2][64],

  1185.                               float *v0, int *v_off, const unsigned int div,

  1186.                               float bias, float scale)

  1187. {

  1188.     int i, n;

  1189.     const float *sbr_qmf_window = div ? sbr_qmf_window_ds : sbr_qmf_window_us;

  1190.     int scale_and_bias = scale != 1.0f || bias != 0.0f;

  1191.     float *v;

  1192.     for (i = 0; i < 32; i++) {

  1193.         if (*v_off == 0) {

  1194.             int saved_samples = (1280 - 128) >> div;

  1195.             memcpy(&v0[SBR_SYNTHESIS_BUF_SIZE - saved_samples], v0, saved_samples * sizeof(float));

  1196.             *v_off = SBR_SYNTHESIS_BUF_SIZE - saved_samples - (128 >> div);

  1197.         } else {

  1198.             *v_off -= 128 >> div;

  1199.         }

  1200.         v = v0 + *v_off;

  1201.         for (n = 1; n < 64 >> div; n+=2) {

  1202.             X[1][i][n] = -X[1][i][n];

  1203.         }

  1204.         if (div) {

  1205.             memset(X[0][i]+32, 0, 32*sizeof(float));

  1206.             memset(X[1][i]+32, 0, 32*sizeof(float));

  1207.         }

  1208.         ff_imdct_half(mdct, mdct_buf[0], X[0][i]);

  1209.         ff_imdct_half(mdct, mdct_buf[1], X[1][i]);

  1210.         if (div) {

  1211.             for (n = 0; n < 32; n++) {

  1212.                 v[      n] = -mdct_buf[0][63 - 2*n] + mdct_buf[1][2*n    ];

  1213.                 v[ 63 - n] =  mdct_buf[0][62 - 2*n] + mdct_buf[1][2*n + 1];

  1214.             }

  1215.         } else {

  1216.             for (n = 0; n < 64; n++) {

  1217.                 v[      n] = -mdct_buf[0][63 -   n] + mdct_buf[1][  n    ];

  1218.                 v[127 - n] =  mdct_buf[0][63 -   n] + mdct_buf[1][  n    ];

  1219.             }

  1220.         }

  1221.         dsp->vector_fmul_add(out, v                , sbr_qmf_window               , zero64, 64 >> div);

  1222.         dsp->vector_fmul_add(out, v + ( 192 >> div), sbr_qmf_window + ( 64 >> div), out   , 64 >> div);

  1223.         dsp->vector_fmul_add(out, v + ( 256 >> div), sbr_qmf_window + (128 >> div), out   , 64 >> div);

  1224.         dsp->vector_fmul_add(out, v + ( 448 >> div), sbr_qmf_window + (192 >> div), out   , 64 >> div);

  1225.         dsp->vector_fmul_add(out, v + ( 512 >> div), sbr_qmf_window + (256 >> div), out   , 64 >> div);

  1226.         dsp->vector_fmul_add(out, v + ( 704 >> div), sbr_qmf_window + (320 >> div), out   , 64 >> div);

  1227.         dsp->vector_fmul_add(out, v + ( 768 >> div), sbr_qmf_window + (384 >> div), out   , 64 >> div);

  1228.         dsp->vector_fmul_add(out, v + ( 960 >> div), sbr_qmf_window + (448 >> div), out   , 64 >> div);

  1229.         dsp->vector_fmul_add(out, v + (1024 >> div), sbr_qmf_window + (512 >> div), out   , 64 >> div);

  1230.         dsp->vector_fmul_add(out, v + (1216 >> div), sbr_qmf_window + (576 >> div), out   , 64 >> div);

  1231.         if (scale_and_bias)

  1232.             for (n = 0; n < 64 >> div; n++)

  1233.                 out[n] = out[n] * scale + bias;

  1234.         out += 64 >> div;

  1235.     }

  1236. }

  1237. 

  1238. static void autocorrelate(const float x[40][2], float phi[3][2][2], int lag)

  1239. {

  1240.     int i;

  1241.     float real_sum = 0.0f;

  1242.     float imag_sum = 0.0f;

  1243.     if (lag) {

  1244.         for (i = 1; i < 38; i++) {

  1245.             real_sum += x[i][0] * x[i+lag][0] + x[i][1] * x[i+lag][1];

  1246.             imag_sum += x[i][0] * x[i+lag][1] - x[i][1] * x[i+lag][0];

  1247.         }

  1248.         phi[2-lag][1][0] = real_sum + x[ 0][0] * x[lag][0] + x[ 0][1] * x[lag][1];

  1249.         phi[2-lag][1][1] = imag_sum + x[ 0][0] * x[lag][1] - x[ 0][1] * x[lag][0];

  1250.         if (lag == 1) {

  1251.             phi[0][0][0] = real_sum + x[38][0] * x[39][0] + x[38][1] * x[39][1];

  1252.             phi[0][0][1] = imag_sum + x[38][0] * x[39][1] - x[38][1] * x[39][0];

  1253.         }

  1254.     } else {

  1255.         for (i = 1; i < 38; i++) {

  1256.             real_sum += x[i][0] * x[i][0] + x[i][1] * x[i][1];

  1257.         }

  1258.         phi[2][1][0] = real_sum + x[ 0][0] * x[ 0][0] + x[ 0][1] * x[ 0][1];

  1259.         phi[1][0][0] = real_sum + x[38][0] * x[38][0] + x[38][1] * x[38][1];

  1260.     }

  1261. }

  1262. 

  1263. /** High Frequency Generation (14496-3 sp04 p214+) and Inverse Filtering

  1264.  * (14496-3 sp04 p214)

  1265.  * Warning: This routine does not seem numerically stable.

  1266.  */

  1267. static void sbr_hf_inverse_filter(float (*alpha0)[2], float (*alpha1)[2],

  1268.                                   const float X_low[32][40][2], int k0)

  1269. {

  1270.     int k;

  1271.     for (k = 0; k < k0; k++) {

  1272.         float phi[3][2][2], dk;

  1273. 

  1274.         autocorrelate(X_low[k], phi, 0);

  1275.         autocorrelate(X_low[k], phi, 1);

  1276.         autocorrelate(X_low[k], phi, 2);

  1277. 

  1278.         dk =  phi[2][1][0] * phi[1][0][0] -

  1279.              (phi[1][1][0] * phi[1][1][0] + phi[1][1][1] * phi[1][1][1]) / 1.000001f;

  1280. 

  1281.         if (!dk) {

  1282.             alpha1[k][0] = 0;

  1283.             alpha1[k][1] = 0;

  1284.         } else {

  1285.             float temp_real, temp_im;

  1286.             temp_real = phi[0][0][0] * phi[1][1][0] -

  1287.                         phi[0][0][1] * phi[1][1][1] -

  1288.                         phi[0][1][0] * phi[1][0][0];

  1289.             temp_im   = phi[0][0][0] * phi[1][1][1] +

  1290.                         phi[0][0][1] * phi[1][1][0] -

  1291.                         phi[0][1][1] * phi[1][0][0];

  1292. 

  1293.             alpha1[k][0] = temp_real / dk;

  1294.             alpha1[k][1] = temp_im   / dk;

  1295.         }

  1296. 

  1297.         if (!phi[1][0][0]) {

  1298.             alpha0[k][0] = 0;

  1299.             alpha0[k][1] = 0;

  1300.         } else {

  1301.             float temp_real, temp_im;

  1302.             temp_real = phi[0][0][0] + alpha1[k][0] * phi[1][1][0] +

  1303.                                        alpha1[k][1] * phi[1][1][1];

  1304.             temp_im   = phi[0][0][1] + alpha1[k][1] * phi[1][1][0] -

  1305.                                        alpha1[k][0] * phi[1][1][1];

  1306. 

  1307.             alpha0[k][0] = -temp_real / phi[1][0][0];

  1308.             alpha0[k][1] = -temp_im   / phi[1][0][0];

  1309.         }

  1310. 

  1311.         if (alpha1[k][0] * alpha1[k][0] + alpha1[k][1] * alpha1[k][1] >= 16.0f ||

  1312.            alpha0[k][0] * alpha0[k][0] + alpha0[k][1] * alpha0[k][1] >= 16.0f) {

  1313.             alpha1[k][0] = 0;

  1314.             alpha1[k][1] = 0;

  1315.             alpha0[k][0] = 0;

  1316.             alpha0[k][1] = 0;

  1317.         }

  1318.     }

  1319. }

  1320. 

  1321. /// Chirp Factors (14496-3 sp04 p214)

  1322. static void sbr_chirp(SpectralBandReplication *sbr, SBRData *ch_data)

  1323. {

  1324.     int i;

  1325.     float new_bw;

  1326.     static const float bw_tab[] = { 0.0f, 0.75f, 0.9f, 0.98f };

  1327. 

  1328.     for (i = 0; i < sbr->n_q; i++) {

  1329.         if (ch_data->bs_invf_mode[0][i] + ch_data->bs_invf_mode[1][i] == 1) {

  1330.             new_bw = 0.6f;

  1331.         } else

  1332.             new_bw = bw_tab[ch_data->bs_invf_mode[0][i]];

  1333. 

  1334.         if (new_bw < ch_data->bw_array[i]) {

  1335.             new_bw = 0.75f    * new_bw + 0.25f    * ch_data->bw_array[i];

  1336.         } else

  1337.             new_bw = 0.90625f * new_bw + 0.09375f * ch_data->bw_array[i];

  1338.         ch_data->bw_array[i] = new_bw < 0.015625f ? 0.0f : new_bw;

  1339.     }

  1340. }

  1341. 

  1342. /// Generate the subband filtered lowband

  1343. static int sbr_lf_gen(AACContext *ac, SpectralBandReplication *sbr,

  1344.                       float X_low[32][40][2], const float W[2][32][32][2])

  1345. {

  1346.     int i, k;

  1347.     const int t_HFGen = 8;

  1348.     const int i_f = 32;

  1349.     memset(X_low, 0, 32*sizeof(*X_low));

  1350.     for (k = 0; k < sbr->kx[1]; k++) {

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

  1352.             X_low[k][i][0] = W[1][i - t_HFGen][k][0];

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

  1354.         }

  1355.     }

  1356.     for (k = 0; k < sbr->kx[0]; k++) {

  1357.         for (i = 0; i < t_HFGen; i++) {

  1358.             X_low[k][i][0] = W[0][i + i_f - t_HFGen][k][0];

  1359.             X_low[k][i][1] = W[0][i + i_f - t_HFGen][k][1];

  1360.         }

  1361.     }

  1362.     return 0;

  1363. }

  1364. 

  1365. /// High Frequency Generator (14496-3 sp04 p215)

  1366. static int sbr_hf_gen(AACContext *ac, SpectralBandReplication *sbr,

  1367.                       float X_high[64][40][2], const float X_low[32][40][2],

  1368.                       const float (*alpha0)[2], const float (*alpha1)[2],

  1369.                       const float bw_array[5], const uint8_t *t_env,

  1370.                       int bs_num_env)

  1371. {

  1372.     int i, j, x;

  1373.     int g = 0;

  1374.     int k = sbr->kx[1];

  1375.     for (j = 0; j < sbr->num_patches; j++) {

  1376.         for (x = 0; x < sbr->patch_num_subbands[j]; x++, k++) {

  1377.             float alpha[4];

  1378.             const int p = sbr->patch_start_subband[j] + x;

  1379.             while (g <= sbr->n_q && k >= sbr->f_tablenoise[g])

  1380.                 g++;

  1381.             g--;

  1382. 

  1383.             if (g < 0) {

  1384.                 av_log(ac->avccontext, AV_LOG_ERROR,

  1385.                        "ERROR : no subband found for frequency %d\n", k);

  1386.                 return -1;

  1387.             }

  1388. 

  1389.             alpha[0] = alpha1[p][0] * bw_array[g] * bw_array[g];

  1390.             alpha[1] = alpha1[p][1] * bw_array[g] * bw_array[g];

  1391.             alpha[2] = alpha0[p][0] * bw_array[g];

  1392.             alpha[3] = alpha0[p][1] * bw_array[g];

  1393. 

  1394.             for (i = 2 * t_env[0]; i < 2 * t_env[bs_num_env]; i++) {

  1395.                 const int idx = i + ENVELOPE_ADJUSTMENT_OFFSET;

  1396.                 X_high[k][idx][0] =

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

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

  1399.                     X_low[p][idx - 1][0] * alpha[2] -

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

  1401.                     X_low[p][idx][0];

  1402.                 X_high[k][idx][1] =

  1403.                     X_low[p][idx - 2][1] * alpha[0] +

  1404.                     X_low[p][idx - 2][0] * alpha[1] +

  1405.                     X_low[p][idx - 1][1] * alpha[2] +

  1406.                     X_low[p][idx - 1][0] * alpha[3] +

  1407.                     X_low[p][idx][1];

  1408.             }

  1409.         }

  1410.     }

  1411.     if (k < sbr->m[1] + sbr->kx[1])

  1412.         memset(X_high + k, 0, (sbr->m[1] + sbr->kx[1] - k) * sizeof(*X_high));

  1413. 

  1414.     return 0;

  1415. }

  1416. 

  1417. /// Generate the subband filtered lowband

  1418. static int sbr_x_gen(SpectralBandReplication *sbr, float X[2][32][64],

  1419.                      const float X_low[32][40][2], const float Y[2][38][64][2],

  1420.                      int ch)

  1421. {

  1422.     int k, i;

  1423.     const int i_f = 32;

  1424.     const int i_Temp = FFMAX(2*sbr->data[ch].t_env_num_env_old - i_f, 0);

  1425.     memset(X, 0, 2*sizeof(*X));

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

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

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

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

  1430.         }

  1431.     }

  1432.     for (; k < sbr->kx[0] + sbr->m[0]; k++) {

  1433.         for (i = 0; i < i_Temp; i++) {

  1434.             X[0][i][k] = Y[0][i + i_f][k][0];

  1435.             X[1][i][k] = Y[0][i + i_f][k][1];

  1436.         }

  1437.     }

  1438. 

  1439.     for (k = 0; k < sbr->kx[1]; k++) {

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

  1441.             X[0][i][k] = X_low[k][i + ENVELOPE_ADJUSTMENT_OFFSET][0];

  1442.             X[1][i][k] = X_low[k][i + ENVELOPE_ADJUSTMENT_OFFSET][1];

  1443.         }

  1444.     }

  1445.     for (; k < sbr->kx[1] + sbr->m[1]; k++) {

  1446.         for (i = i_Temp; i < i_f; i++) {

  1447.             X[0][i][k] = Y[1][i][k][0];

  1448.             X[1][i][k] = Y[1][i][k][1];

  1449.         }

  1450.     }

  1451.     return 0;

  1452. }

  1453. 

  1454. /** High Frequency Adjustment (14496-3 sp04 p217) and Mapping

  1455.  * (14496-3 sp04 p217)

  1456.  */

  1457. static void sbr_mapping(AACContext *ac, SpectralBandReplication *sbr,

  1458.                         SBRData *ch_data, int e_a[2])

  1459. {

  1460.     int e, i, m;

  1461. 

  1462.     e_a[0] = -(e_a[1] != ch_data->bs_num_env[0]); // l_APrev

  1463.     e_a[1] = -1;

  1464.     if ((ch_data->bs_frame_class & 1) && ch_data->bs_pointer) { // FIXVAR or VARVAR and bs_pointer != 0

  1465.         e_a[1] = ch_data->bs_num_env[1] + 1 - ch_data->bs_pointer;

  1466.     } else if ((ch_data->bs_frame_class == 2) && (ch_data->bs_pointer > 1)) // VARFIX and bs_pointer > 1

  1467.         e_a[1] = ch_data->bs_pointer - 1;

  1468. 

  1469.     memset(ch_data->s_indexmapped[1], 0, 7*sizeof(ch_data->s_indexmapped[1]));

  1470.     for (e = 0; e < ch_data->bs_num_env[1]; e++) {

  1471.         const unsigned int ilim = sbr->n[ch_data->bs_freq_res[e + 1]];

  1472.         uint16_t *table = ch_data->bs_freq_res[e + 1] ? sbr->f_tablehigh : sbr->f_tablelow;

  1473.         int k;

  1474. 

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

  1476.             for (m = table[i]; m < table[i + 1]; m++)

  1477.                 sbr->e_origmapped[e][m - sbr->kx[1]] = ch_data->env_facs[e+1][i];

  1478. 

  1479.         // ch_data->bs_num_noise > 1 => 2 noise floors

  1480.         k = (ch_data->bs_num_noise > 1) && (ch_data->t_env[e] >= ch_data->t_q[1]);

  1481.         for (i = 0; i < sbr->n_q; i++)

  1482.             for (m = sbr->f_tablenoise[i]; m < sbr->f_tablenoise[i + 1]; m++)

  1483.                 sbr->q_mapped[e][m - sbr->kx[1]] = ch_data->noise_facs[k+1][i];

  1484. 

  1485.         for (i = 0; i < sbr->n[1]; i++) {

  1486.             if (ch_data->bs_add_harmonic_flag) {

  1487.                 const unsigned int m_midpoint =

  1488.                     (sbr->f_tablehigh[i] + sbr->f_tablehigh[i + 1]) >> 1;

  1489. 

  1490.                 ch_data->s_indexmapped[e + 1][m_midpoint - sbr->kx[1]] = ch_data->bs_add_harmonic[i] *

  1491.                     (e >= e_a[1] || (ch_data->s_indexmapped[0][m_midpoint - sbr->kx[1]] == 1));

  1492.             }

  1493.         }

  1494. 

  1495.         for (i = 0; i < ilim; i++) {

  1496.             int additional_sinusoid_present = 0;

  1497.             for (m = table[i]; m < table[i + 1]; m++) {

  1498.                 if (ch_data->s_indexmapped[e + 1][m - sbr->kx[1]]) {

  1499.                     additional_sinusoid_present = 1;

  1500.                     break;

  1501.                 }

  1502.             }

  1503.             memset(&sbr->s_mapped[e][table[i] - sbr->kx[1]], additional_sinusoid_present,

  1504.                    (table[i + 1] - table[i]) * sizeof(sbr->s_mapped[e][0]));

  1505.         }

  1506.     }

  1507. 

  1508.     memcpy(ch_data->s_indexmapped[0], ch_data->s_indexmapped[ch_data->bs_num_env[1]], sizeof(ch_data->s_indexmapped[0]));

  1509. }

  1510. 

  1511. /// Estimation of current envelope (14496-3 sp04 p218)

  1512. static void sbr_env_estimate(float (*e_curr)[48], float X_high[64][40][2],

  1513.                              SpectralBandReplication *sbr, SBRData *ch_data)

  1514. {

  1515.     int e, i, m;

  1516. 

  1517.     if (sbr->bs_interpol_freq) {

  1518.         for (e = 0; e < ch_data->bs_num_env[1]; e++) {

  1519.             const float recip_env_size = 0.5f / (ch_data->t_env[e + 1] - ch_data->t_env[e]);

  1520.             int ilb = ch_data->t_env[e]     * 2 + ENVELOPE_ADJUSTMENT_OFFSET;

  1521.             int iub = ch_data->t_env[e + 1] * 2 + ENVELOPE_ADJUSTMENT_OFFSET;

  1522. 

  1523.             for (m = 0; m < sbr->m[1]; m++) {

  1524.                 float sum = 0.0f;

  1525. 

  1526.                 for (i = ilb; i < iub; i++) {

  1527.                     sum += X_high[m + sbr->kx[1]][i][0] * X_high[m + sbr->kx[1]][i][0] +

  1528.                            X_high[m + sbr->kx[1]][i][1] * X_high[m + sbr->kx[1]][i][1];

  1529.                 }

  1530.                 e_curr[e][m] = sum * recip_env_size;

  1531.             }

  1532.         }

  1533.     } else {

  1534.         int k, p;

  1535. 

  1536.         for (e = 0; e < ch_data->bs_num_env[1]; e++) {

  1537.             const int env_size = 2 * (ch_data->t_env[e + 1] - ch_data->t_env[e]);

  1538.             int ilb = ch_data->t_env[e]     * 2 + ENVELOPE_ADJUSTMENT_OFFSET;

  1539.             int iub = ch_data->t_env[e + 1] * 2 + ENVELOPE_ADJUSTMENT_OFFSET;

  1540.             const uint16_t *table = ch_data->bs_freq_res[e + 1] ? sbr->f_tablehigh : sbr->f_tablelow;

  1541. 

  1542.             for (p = 0; p < sbr->n[ch_data->bs_freq_res[e + 1]]; p++) {

  1543.                 float sum = 0.0f;

  1544.                 const int den = env_size * (table[p + 1] - table[p]);

  1545. 

  1546.                 for (k = table[p]; k < table[p + 1]; k++) {

  1547.                     for (i = ilb; i < iub; i++) {

  1548.                         sum += X_high[k][i][0] * X_high[k][i][0] +

  1549.                                X_high[k][i][1] * X_high[k][i][1];

  1550.                     }

  1551.                 }

  1552.                 sum /= den;

  1553.                 for (k = table[p]; k < table[p + 1]; k++) {

  1554.                     e_curr[e][k - sbr->kx[1]] = sum;

  1555.                 }

  1556.             }

  1557.         }

  1558.     }

  1559. }

  1560. 

  1561. /**

  1562.  * Calculation of levels of additional HF signal components (14496-3 sp04 p219)

  1563.  * and Calculation of gain (14496-3 sp04 p219)

  1564.  */

  1565. static void sbr_gain_calc(AACContext *ac, SpectralBandReplication *sbr,

  1566.                           SBRData *ch_data, const int e_a[2])

  1567. {

  1568.     int e, k, m;

  1569.     // max gain limits : -3dB, 0dB, 3dB, inf dB (limiter off)

  1570.     static const float limgain[4] = { 0.70795, 1.0, 1.41254, 10000000000 };

  1571. 

  1572.     for (e = 0; e < ch_data->bs_num_env[1]; e++) {

  1573.         int delta = !((e == e_a[1]) || (e == e_a[0]));

  1574.         for (k = 0; k < sbr->n_lim; k++) {

  1575.             float gain_boost, gain_max;

  1576.             float sum[2] = { 0.0f, 0.0f };

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

  1578.                 const float temp = sbr->e_origmapped[e][m] / (1.0f + sbr->q_mapped[e][m]);

  1579.                 sbr->q_m[e][m] = sqrtf(temp * sbr->q_mapped[e][m]);

  1580.                 sbr->s_m[e][m] = sqrtf(temp * ch_data->s_indexmapped[e + 1][m]);

  1581.                 if (!sbr->s_mapped[e][m]) {

  1582.                     sbr->gain[e][m] = sqrtf(sbr->e_origmapped[e][m] /

  1583.                                             ((1.0f + sbr->e_curr[e][m]) *

  1584.                                              (1.0f + sbr->q_mapped[e][m] * delta)));

  1585.                 } else {

  1586.                     sbr->gain[e][m] = sqrtf(sbr->e_origmapped[e][m] * sbr->q_mapped[e][m] /

  1587.                                             ((1.0f + sbr->e_curr[e][m]) *

  1588.                                              (1.0f + sbr->q_mapped[e][m])));

  1589.                 }

  1590.             }

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

  1592.                 sum[0] += sbr->e_origmapped[e][m];

  1593.                 sum[1] += sbr->e_curr[e][m];

  1594.             }

  1595.             gain_max = limgain[sbr->bs_limiter_gains] * sqrtf((FLT_EPSILON + sum[0]) / (FLT_EPSILON + sum[1]));

  1596.             gain_max = FFMIN(100000, gain_max);

  1597.             for (m = sbr->f_tablelim[k] - sbr->kx[1]; m < sbr->f_tablelim[k + 1] - sbr->kx[1]; m++) {

  1598.                 float q_m_max   = sbr->q_m[e][m] * gain_max / sbr->gain[e][m];

  1599.                 sbr->q_m[e][m]  = FFMIN(sbr->q_m[e][m], q_m_max);

  1600.                 sbr->gain[e][m] = FFMIN(sbr->gain[e][m], gain_max);

  1601.             }

  1602.             sum[0] = sum[1] = 0.0f;

  1603.             for (m = sbr->f_tablelim[k] - sbr->kx[1]; m < sbr->f_tablelim[k + 1] - sbr->kx[1]; m++) {

  1604.                 sum[0] += sbr->e_origmapped[e][m];

  1605.                 sum[1] += sbr->e_curr[e][m] * sbr->gain[e][m] * sbr->gain[e][m]

  1606.                           + sbr->s_m[e][m] * sbr->s_m[e][m]

  1607.                           + (delta && !sbr->s_m[e][m]) * sbr->q_m[e][m] * sbr->q_m[e][m];

  1608.             }

  1609.             gain_boost = sqrtf((FLT_EPSILON + sum[0]) / (FLT_EPSILON + sum[1]));

  1610.             gain_boost = FFMIN(1.584893192, gain_boost);

  1611.             for (m = sbr->f_tablelim[k] - sbr->kx[1]; m < sbr->f_tablelim[k + 1] - sbr->kx[1]; m++) {

  1612.                 sbr->gain[e][m] *= gain_boost;

  1613.                 sbr->q_m[e][m]  *= gain_boost;

  1614.                 sbr->s_m[e][m]  *= gain_boost;

  1615.             }

  1616.         }

  1617.     }

  1618. }

  1619. 

  1620. /// Assembling HF Signals (14496-3 sp04 p220)

  1621. static void sbr_hf_assemble(float Y[2][38][64][2], const float X_high[64][40][2],

  1622.                             SpectralBandReplication *sbr, SBRData *ch_data,

  1623.                             const int e_a[2])

  1624. {

  1625.     int e, i, j, m;

  1626.     const int h_SL = 4 * !sbr->bs_smoothing_mode;

  1627.     const int kx = sbr->kx[1];

  1628.     const int m_max = sbr->m[1];

  1629.     static const float h_smooth[5] = {

  1630.         0.33333333333333,

  1631.         0.30150283239582,

  1632.         0.21816949906249,

  1633.         0.11516383427084,

  1634.         0.03183050093751,

  1635.     };

  1636.     static const int8_t phi[2][4] = {

  1637.         {  1,  0, -1,  0}, // real

  1638.         {  0,  1,  0, -1}, // imaginary

  1639.     };

  1640.     float (*g_temp)[48] = ch_data->g_temp, (*q_temp)[48] = ch_data->q_temp;

  1641.     int indexnoise = ch_data->f_indexnoise;

  1642.     int indexsine  = ch_data->f_indexsine;

  1643.     memcpy(Y[0], Y[1], sizeof(Y[0]));

  1644. 

  1645.     if (sbr->reset) {

  1646.         for (i = 0; i < h_SL; i++) {

  1647.             memcpy(g_temp[i + 2*ch_data->t_env[0]], sbr->gain[0], m_max * sizeof(sbr->gain[0][0]));

  1648.             memcpy(q_temp[i + 2*ch_data->t_env[0]], sbr->q_m[0],  m_max * sizeof(sbr->q_m[0][0]));

  1649.         }

  1650.     } else if (h_SL) {

  1651.         memcpy(g_temp[2*ch_data->t_env[0]], g_temp[2*ch_data->t_env_num_env_old], 4*sizeof(g_temp[0]));

  1652.         memcpy(q_temp[2*ch_data->t_env[0]], q_temp[2*ch_data->t_env_num_env_old], 4*sizeof(q_temp[0]));

  1653.     }

  1654. 

  1655.     for (e = 0; e < ch_data->bs_num_env[1]; e++) {

  1656.         for (i = 2 * ch_data->t_env[e]; i < 2 * ch_data->t_env[e + 1]; i++) {

  1657.             memcpy(g_temp[h_SL + i], sbr->gain[e], m_max * sizeof(sbr->gain[0][0]));

  1658.             memcpy(q_temp[h_SL + i], sbr->q_m[e],  m_max * sizeof(sbr->q_m[0][0]));

  1659.         }

  1660.     }

  1661. 

  1662.     for (e = 0; e < ch_data->bs_num_env[1]; e++) {

  1663.         for (i = 2 * ch_data->t_env[e]; i < 2 * ch_data->t_env[e + 1]; i++) {

  1664.             int phi_sign = (1 - 2*(kx & 1));

  1665. 

  1666.             if (h_SL && e != e_a[0] && e != e_a[1]) {

  1667.                 for (m = 0; m < m_max; m++) {

  1668.                     const int idx1 = i + h_SL;

  1669.                     float g_filt = 0.0f;

  1670.                     for (j = 0; j <= h_SL; j++)

  1671.                         g_filt += g_temp[idx1 - j][m] * h_smooth[j];

  1672.                     Y[1][i][m + kx][0] =

  1673.                         X_high[m + kx][i + ENVELOPE_ADJUSTMENT_OFFSET][0] * g_filt;

  1674.                     Y[1][i][m + kx][1] =

  1675.                         X_high[m + kx][i + ENVELOPE_ADJUSTMENT_OFFSET][1] * g_filt;

  1676.                 }

  1677.             } else {

  1678.                 for (m = 0; m < m_max; m++) {

  1679.                     const float g_filt = g_temp[i + h_SL][m];

  1680.                     Y[1][i][m + kx][0] =

  1681.                         X_high[m + kx][i + ENVELOPE_ADJUSTMENT_OFFSET][0] * g_filt;

  1682.                     Y[1][i][m + kx][1] =

  1683.                         X_high[m + kx][i + ENVELOPE_ADJUSTMENT_OFFSET][1] * g_filt;

  1684.                 }

  1685.             }

  1686. 

  1687.             if (e != e_a[0] && e != e_a[1]) {

  1688.                 for (m = 0; m < m_max; m++) {

  1689.                     indexnoise = (indexnoise + 1) & 0x1ff;

  1690.                     if (sbr->s_m[e][m]) {

  1691.                         Y[1][i][m + kx][0] +=

  1692.                             sbr->s_m[e][m] * phi[0][indexsine];

  1693.                         Y[1][i][m + kx][1] +=

  1694.                             sbr->s_m[e][m] * (phi[1][indexsine] * phi_sign);

  1695.                     } else {

  1696.                         float q_filt;

  1697.                         if (h_SL) {

  1698.                             const int idx1 = i + h_SL;

  1699.                             q_filt = 0.0f;

  1700.                             for (j = 0; j <= h_SL; j++)

  1701.                                 q_filt += q_temp[idx1 - j][m] * h_smooth[j];

  1702.                         } else {

  1703.                             q_filt = q_temp[i][m];

  1704.                         }

  1705.                         Y[1][i][m + kx][0] +=

  1706.                             q_filt * sbr_noise_table[indexnoise][0];

  1707.                         Y[1][i][m + kx][1] +=

  1708.                             q_filt * sbr_noise_table[indexnoise][1];

  1709.                     }

  1710.                     phi_sign = -phi_sign;

  1711.                 }

  1712.             } else {

  1713.                 indexnoise = (indexnoise + m_max) & 0x1ff;

  1714.                 for (m = 0; m < m_max; m++) {

  1715.                     Y[1][i][m + kx][0] +=

  1716.                         sbr->s_m[e][m] * phi[0][indexsine];

  1717.                     Y[1][i][m + kx][1] +=

  1718.                         sbr->s_m[e][m] * (phi[1][indexsine] * phi_sign);

  1719.                     phi_sign = -phi_sign;

  1720.                 }

  1721.             }

  1722.             indexsine = (indexsine + 1) & 3;

  1723.         }

  1724.     }

  1725.     ch_data->f_indexnoise = indexnoise;

  1726.     ch_data->f_indexsine  = indexsine;

  1727. }

  1728. 

  1729. void ff_sbr_dequant(AACContext *ac, SpectralBandReplication *sbr, int id_aac)

  1730. {

  1731.     int ch;

  1732. 

  1733.     if (sbr->start) {

  1734.         for (ch = 0; ch < (id_aac == TYPE_CPE) + 1; ch++) {

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

  1736.         }

  1737.         sbr_dequant(sbr, id_aac);

  1738.     }

  1739. }

  1740. 

  1741. void ff_sbr_apply(AACContext *ac, SpectralBandReplication *sbr, int ch,

  1742.                   const float* in, float* out)

  1743. {

  1744.     int downsampled = ac->m4ac.ext_sample_rate < sbr->sample_rate;

  1745. 

  1746.     /* decode channel */

  1747.     sbr_qmf_analysis(&ac->dsp, &sbr->rdft, in, sbr->data[ch].analysis_filterbank_samples,

  1748.                      (float*)sbr->qmf_filter_scratch,

  1749.                      sbr->data[ch].W, ac->add_bias, 1/(-1024 * ac->sf_scale));

  1750.     sbr_lf_gen(ac, sbr, sbr->X_low, sbr->data[ch].W);

  1751.     if (sbr->start) {

  1752.         sbr_hf_inverse_filter(sbr->alpha0, sbr->alpha1, sbr->X_low, sbr->k[0]);

  1753.         sbr_chirp(sbr, &sbr->data[ch]);

  1754.         sbr_hf_gen(ac, sbr, sbr->X_high, sbr->X_low, sbr->alpha0, sbr->alpha1,

  1755.                    sbr->data[ch].bw_array, sbr->data[ch].t_env,

  1756.                    sbr->data[ch].bs_num_env[1]);

  1757. 

  1758.         // hf_adj

  1759.         sbr_mapping(ac, sbr, &sbr->data[ch], sbr->data[ch].e_a);

  1760.         sbr_env_estimate(sbr->e_curr, sbr->X_high, sbr, &sbr->data[ch]);

  1761.         sbr_gain_calc(ac, sbr, &sbr->data[ch], sbr->data[ch].e_a);

  1762.         sbr_hf_assemble(sbr->data[ch].Y, sbr->X_high, sbr, &sbr->data[ch],

  1763.                         sbr->data[ch].e_a);

  1764.     }

  1765. 

  1766.     /* synthesis */

  1767.     sbr_x_gen(sbr, sbr->X, sbr->X_low, sbr->data[ch].Y, ch);

  1768.     sbr_qmf_synthesis(&ac->dsp, &sbr->mdct, out, sbr->X, sbr->qmf_filter_scratch,

  1769.                       sbr->data[ch].synthesis_filterbank_samples,

  1770.                       &sbr->data[ch].synthesis_filterbank_samples_offset,

  1771.                       downsampled,

  1772.                       ac->add_bias, -1024 * ac->sf_scale);

  1773. }