falkTX
/
FFmpeg
mirror of https://github.com/falkTX/FFmpeg.git
1
0
Fork 0
Code Issues 0 Releases 338 Wiki Activity
You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
23232 Commits
32 Branches
570MB
Tree: 88b51ea948
Branches Tags
${ item.name }
Create branch ${ searchTerm }
from '88b51ea948'
${ noResults }
FFmpeg/libavcodec/aacsbr.c

1760 lines
66KB
Raw Blame History 

  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. 

  34. #include <stdint.h>

  35. #include <float.h>

  36. 

  37. #define ENVELOPE_ADJUSTMENT_OFFSET 2

  38. #define NOISE_FLOOR_OFFSET 6.0f

  39. 

  40. /**

  41.  * SBR VLC tables

  42.  */

  43. enum {

  44.     T_HUFFMAN_ENV_1_5DB,

  45.     F_HUFFMAN_ENV_1_5DB,

  46.     T_HUFFMAN_ENV_BAL_1_5DB,

  47.     F_HUFFMAN_ENV_BAL_1_5DB,

  48.     T_HUFFMAN_ENV_3_0DB,

  49.     F_HUFFMAN_ENV_3_0DB,

  50.     T_HUFFMAN_ENV_BAL_3_0DB,

  51.     F_HUFFMAN_ENV_BAL_3_0DB,

  52.     T_HUFFMAN_NOISE_3_0DB,

  53.     T_HUFFMAN_NOISE_BAL_3_0DB,

  54. };

  55. 

  56. /**

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

  58.  */

  59. enum {

  60.     FIXFIX,

  61.     FIXVAR,

  62.     VARFIX,

  63.     VARVAR,

  64. };

  65. 

  66. enum {

  67.     EXTENSION_ID_PS = 2,

  68. };

  69. 

  70. static VLC vlc_sbr[10];

  71. static const int8_t vlc_sbr_lav[10] =

  72.     { 60, 60, 24, 24, 31, 31, 12, 12, 31, 12 };

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

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

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

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

  77. 

  78. #define SBR_INIT_VLC_STATIC(num, size) \

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

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

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

  82.                     size)

  83. 

  84. #define SBR_VLC_ROW(name) \

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

  86. 

  87. av_cold void ff_aac_sbr_init(void)

  88. {

  89.     int n, k;

  90.     static const struct {

  91.         const void *sbr_codes, *sbr_bits;

  92.         const unsigned int table_size, elem_size;

  93.     } sbr_tmp[] = {

  94.         SBR_VLC_ROW(t_huffman_env_1_5dB),

  95.         SBR_VLC_ROW(f_huffman_env_1_5dB),

  96.         SBR_VLC_ROW(t_huffman_env_bal_1_5dB),

  97.         SBR_VLC_ROW(f_huffman_env_bal_1_5dB),

  98.         SBR_VLC_ROW(t_huffman_env_3_0dB),

  99.         SBR_VLC_ROW(f_huffman_env_3_0dB),

  100.         SBR_VLC_ROW(t_huffman_env_bal_3_0dB),

  101.         SBR_VLC_ROW(f_huffman_env_bal_3_0dB),

  102.         SBR_VLC_ROW(t_huffman_noise_3_0dB),

  103.         SBR_VLC_ROW(t_huffman_noise_bal_3_0dB),

  104.     };

  105. 

  106.     // SBR VLC table initialization

  107.     SBR_INIT_VLC_STATIC(0, 1098);

  108.     SBR_INIT_VLC_STATIC(1, 1092);

  109.     SBR_INIT_VLC_STATIC(2, 768);

  110.     SBR_INIT_VLC_STATIC(3, 1026);

  111.     SBR_INIT_VLC_STATIC(4, 1058);

  112.     SBR_INIT_VLC_STATIC(5, 1052);

  113.     SBR_INIT_VLC_STATIC(6, 544);

  114.     SBR_INIT_VLC_STATIC(7, 544);

  115.     SBR_INIT_VLC_STATIC(8, 592);

  116.     SBR_INIT_VLC_STATIC(9, 512);

  117. 

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

  119.         float pre = M_PI * n / 64;

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

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

  122.     }

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

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

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

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

  127.     }

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

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

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

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

  132. 

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

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

  135. }

  136. 

  137. av_cold void ff_aac_sbr_ctx_init(SpectralBandReplication *sbr)

  138. {

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

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

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

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

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

  144. }

  145. 

  146. av_cold void ff_aac_sbr_ctx_close(SpectralBandReplication *sbr)

  147. {

  148.     ff_mdct_end(&sbr->mdct);

  149.     ff_rdft_end(&sbr->rdft);

  150. }

  151. 

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

  153. {

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

  155. }

  156. 

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

  158. {

  159.     int i;

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

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

  162.             return 1;

  163.     return 0;

  164. }

  165. 

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

  167. static void sbr_make_f_tablelim(SpectralBandReplication *sbr)

  168. {

  169.     int k;

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

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

  172.                                                1.18509277094158210129f,   //2^(0.49/2)

  173.                                                1.11987160404675912501f }; //2^(0.49/3)

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

  175.         int16_t patch_borders[5];

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

  177. 

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

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

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

  181. 

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

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

  184.         if (sbr->num_patches > 1)

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

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

  187. 

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

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

  190.               qsort_comparison_function_int16);

  191. 

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

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

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

  195.                 *++out = *in++;

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

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

  198.                 in++;

  199.                 sbr->n_lim--;

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

  201.                 *out = *in++;

  202.                 sbr->n_lim--;

  203.             } else {

  204.                 *++out = *in++;

  205.             }

  206.         }

  207.     } else {

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

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

  210.         sbr->n_lim = 1;

  211.     }

  212. }

  213. 

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

  215. {

  216.     unsigned int cnt = get_bits_count(gb);

  217.     uint8_t bs_header_extra_1;

  218.     uint8_t bs_header_extra_2;

  219.     int old_bs_limiter_bands = sbr->bs_limiter_bands;

  220.     SpectrumParameters old_spectrum_params;

  221. 

  222.     sbr->start = 1;

  223. 

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

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

  226. 

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

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

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

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

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

  232. 

  233.     bs_header_extra_1 = get_bits1(gb);

  234.     bs_header_extra_2 = get_bits1(gb);

  235. 

  236.     if (bs_header_extra_1) {

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

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

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

  240.     } else {

  241.         sbr->spectrum_params.bs_freq_scale  = 2;

  242.         sbr->spectrum_params.bs_alter_scale = 1;

  243.         sbr->spectrum_params.bs_noise_bands = 2;

  244.     }

  245. 

  246.     // Check if spectrum parameters changed

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

  248.         sbr->reset = 1;

  249. 

  250.     if (bs_header_extra_2) {

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

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

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

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

  255.     } else {

  256.         sbr->bs_limiter_bands  = 2;

  257.         sbr->bs_limiter_gains  = 2;

  258.         sbr->bs_interpol_freq  = 1;

  259.         sbr->bs_smoothing_mode = 1;

  260.     }

  261. 

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

  263.         sbr_make_f_tablelim(sbr);

  264. 

  265.     return get_bits_count(gb) - cnt;

  266. }

  267. 

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

  269. {

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

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

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

  273.     return min;

  274. }

  275. 

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

  277. {

  278.     int k, previous, present;

  279.     float base, prod;

  280. 

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

  282.     prod = start;

  283.     previous = start;

  284. 

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

  286.         prod *= base;

  287.         present  = lrintf(prod);

  288.         bands[k] = present - previous;

  289.         previous = present;

  290.     }

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

  292. }

  293. 

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

  295. {

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

  297.     if (n_master <= 0) {

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

  299.         return -1;

  300.     }

  301.     if (bs_xover_band >= n_master) {

  302.         av_log(avccontext, AV_LOG_ERROR,

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

  304.                bs_xover_band);

  305.         return -1;

  306.     }

  307.     return 0;

  308. }

  309. 

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

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

  312.                              SpectrumParameters *spectrum)

  313. {

  314.     unsigned int temp, max_qmf_subbands;

  315.     unsigned int start_min, stop_min;

  316.     int k;

  317.     const int8_t *sbr_offset_ptr;

  318.     int16_t stop_dk[13];

  319. 

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

  321.         temp = 3000;

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

  323.         temp = 4000;

  324.     } else

  325.         temp = 5000;

  326. 

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

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

  329. 

  330.     switch (sbr->sample_rate) {

  331.     case 16000:

  332.         sbr_offset_ptr = sbr_offset[0];

  333.         break;

  334.     case 22050:

  335.         sbr_offset_ptr = sbr_offset[1];

  336.         break;

  337.     case 24000:

  338.         sbr_offset_ptr = sbr_offset[2];

  339.         break;

  340.     case 32000:

  341.         sbr_offset_ptr = sbr_offset[3];

  342.         break;

  343.     case 44100: case 48000: case 64000:

  344.         sbr_offset_ptr = sbr_offset[4];

  345.         break;

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

  347.         sbr_offset_ptr = sbr_offset[5];

  348.         break;

  349.     default:

  350.         av_log(ac->avccontext, AV_LOG_ERROR,

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

  352.         return -1;

  353.     }

  354. 

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

  356. 

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

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

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

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

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

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

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

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

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

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

  367.     } else {

  368.         av_log(ac->avccontext, AV_LOG_ERROR,

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

  370.         return -1;

  371.     }

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

  373. 

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

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

  376.         max_qmf_subbands = 48;

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

  378.         max_qmf_subbands = 35;

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

  380.         max_qmf_subbands = 32;

  381. 

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

  383.         av_log(ac->avccontext, AV_LOG_ERROR,

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

  385.         return -1;

  386.     }

  387. 

  388.     if (!spectrum->bs_freq_scale) {

  389.         unsigned int dk;

  390.         int k2diff;

  391. 

  392.         dk = spectrum->bs_alter_scale + 1;

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

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

  395.             return -1;

  396. 

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

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

  399. 

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

  401.         if (k2diff < 0) {

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

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

  404.         } else if (k2diff) {

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

  406.         }

  407. 

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

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

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

  411. 

  412.     } else {

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

  414.         int two_regions, num_bands_0;

  415.         int vdk0_max, vdk1_min;

  416.         int16_t vk0[49];

  417. 

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

  419.             two_regions = 1;

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

  421.         } else {

  422.             two_regions = 0;

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

  424.         }

  425. 

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

  427. 

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

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

  430.             return -1;

  431.         }

  432. 

  433.         vk0[0] = 0;

  434. 

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

  436. 

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

  438.         vdk0_max = vk0[num_bands_0];

  439. 

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

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

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

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

  444.                 return -1;

  445.             }

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

  447.         }

  448. 

  449.         if (two_regions) {

  450.             int16_t vk1[49];

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

  452.                                                      : 1.0f; // bs_alter_scale = {0,1}

  453.             int num_bands_1 = lrintf(half_bands * invwarp *

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

  455. 

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

  457. 

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

  459. 

  460.             if (vdk1_min < vdk0_max) {

  461.                 int change;

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

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

  464.                 vk1[1]           += change;

  465.                 vk1[num_bands_1] -= change;

  466.             }

  467. 

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

  469. 

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

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

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

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

  474.                     return -1;

  475.                 }

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

  477.             }

  478. 

  479.             sbr->n_master = num_bands_0 + num_bands_1;

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

  481.                 return -1;

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

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

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

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

  486. 

  487.         } else {

  488.             sbr->n_master = num_bands_0;

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

  490.                 return -1;

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

  492.         }

  493.     }

  494. 

  495.     return 0;

  496. }

  497. 

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

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

  500. {

  501.     int i, k, sb = 0;

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

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

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

  505. 

  506.     sbr->num_patches = 0;

  507. 

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

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

  510.     } else

  511.         k = sbr->n_master;

  512. 

  513.     do {

  514.         int odd = 0;

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

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

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

  518.         }

  519. 

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

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

  522. 

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

  524.             usb = sb;

  525.             msb = sb;

  526.             sbr->num_patches++;

  527.         } else

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

  529. 

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

  531.             k = sbr->n_master;

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

  533. 

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

  535.         sbr->num_patches--;

  536. 

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

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

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

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

  541.         return -1;

  542.     }

  543. 

  544.     return 0;

  545. }

  546. 

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

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

  549. {

  550.     int k, temp;

  551. 

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

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

  554. 

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

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

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

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

  559. 

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

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

  562.         av_log(ac->avccontext, AV_LOG_ERROR,

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

  564.         return -1;

  565.     }

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

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

  568.         return -1;

  569.     }

  570. 

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

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

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

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

  575. 

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

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

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

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

  580.         return -1;

  581.     }

  582. 

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

  584.     temp = 0;

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

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

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

  588.     }

  589. 

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

  591.         return -1;

  592. 

  593.     sbr_make_f_tablelim(sbr);

  594. 

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

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

  597. 

  598.     return 0;

  599. }

  600. 

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

  602.                                               int elements)

  603. {

  604.     int i;

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

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

  607.     }

  608. }

  609. 

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

  611. static const int8_t ceil_log2[] = {

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

  613. };

  614. 

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

  616.                          GetBitContext *gb, SBRData *ch_data)

  617. {

  618.     int i;

  619. 

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

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

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

  623. 

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

  625.     case FIXFIX:

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

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

  628.             ch_data->bs_amp_res = 0;

  629. 

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

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

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

  633.         break;

  634.     case FIXVAR:

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

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

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

  638. 

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

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

  641. 

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

  643. 

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

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

  646.         break;

  647.     case VARFIX:

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

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

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

  651. 

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

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

  654. 

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

  656. 

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

  658.         break;

  659.     case VARVAR:

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

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

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

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

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

  665. 

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

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

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

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

  670. 

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

  672. 

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

  674.         break;

  675.     }

  676. 

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

  678.         av_log(ac->avccontext, AV_LOG_ERROR,

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

  680.                ch_data->bs_num_env[1]);

  681.         return -1;

  682.     }

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

  684.         av_log(ac->avccontext, AV_LOG_ERROR,

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

  686.                ch_data->bs_num_env[1]);

  687.         return -1;

  688.     }

  689. 

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

  691. 

  692.     return 0;

  693. }

  694. 

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

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

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

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

  699. 

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

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

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

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

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

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

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

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

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

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

  710. }

  711. 

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

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

  714.                           SBRData *ch_data)

  715. {

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

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

  718. }

  719. 

  720. /// Read inverse filtering data

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

  722.                           SBRData *ch_data)

  723. {

  724.     int i;

  725. 

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

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

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

  729. }

  730. 

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

  732.                               SBRData *ch_data, int ch)

  733. {

  734.     int bits;

  735.     int i, j, k;

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

  737.     int t_lav, f_lav;

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

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

  740. 

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

  742.         if (ch_data->bs_amp_res) {

  743.             bits   = 5;

  744.             t_huff = vlc_sbr[T_HUFFMAN_ENV_BAL_3_0DB].table;

  745.             t_lav  = vlc_sbr_lav[T_HUFFMAN_ENV_BAL_3_0DB];

  746.             f_huff = vlc_sbr[F_HUFFMAN_ENV_BAL_3_0DB].table;

  747.             f_lav  = vlc_sbr_lav[F_HUFFMAN_ENV_BAL_3_0DB];

  748.         } else {

  749.             bits   = 6;

  750.             t_huff = vlc_sbr[T_HUFFMAN_ENV_BAL_1_5DB].table;

  751.             t_lav  = vlc_sbr_lav[T_HUFFMAN_ENV_BAL_1_5DB];

  752.             f_huff = vlc_sbr[F_HUFFMAN_ENV_BAL_1_5DB].table;

  753.             f_lav  = vlc_sbr_lav[F_HUFFMAN_ENV_BAL_1_5DB];

  754.         }

  755.     } else {

  756.         if (ch_data->bs_amp_res) {

  757.             bits   = 6;

  758.             t_huff = vlc_sbr[T_HUFFMAN_ENV_3_0DB].table;

  759.             t_lav  = vlc_sbr_lav[T_HUFFMAN_ENV_3_0DB];

  760.             f_huff = vlc_sbr[F_HUFFMAN_ENV_3_0DB].table;

  761.             f_lav  = vlc_sbr_lav[F_HUFFMAN_ENV_3_0DB];

  762.         } else {

  763.             bits   = 7;

  764.             t_huff = vlc_sbr[T_HUFFMAN_ENV_1_5DB].table;

  765.             t_lav  = vlc_sbr_lav[T_HUFFMAN_ENV_1_5DB];

  766.             f_huff = vlc_sbr[F_HUFFMAN_ENV_1_5DB].table;

  767.             f_lav  = vlc_sbr_lav[F_HUFFMAN_ENV_1_5DB];

  768.         }

  769.     }

  770. 

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

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

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

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

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

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

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

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

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

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

  781.                 }

  782.             } else {

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

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

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

  786.                 }

  787.             }

  788.         } else {

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

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

  791.                 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);

  792.         }

  793.     }

  794. 

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

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

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

  798. }

  799. 

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

  801.                            SBRData *ch_data, int ch)

  802. {

  803.     int i, j;

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

  805.     int t_lav, f_lav;

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

  807. 

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

  809.         t_huff = vlc_sbr[T_HUFFMAN_NOISE_BAL_3_0DB].table;

  810.         t_lav  = vlc_sbr_lav[T_HUFFMAN_NOISE_BAL_3_0DB];

  811.         f_huff = vlc_sbr[F_HUFFMAN_ENV_BAL_3_0DB].table;

  812.         f_lav  = vlc_sbr_lav[F_HUFFMAN_ENV_BAL_3_0DB];

  813.     } else {

  814.         t_huff = vlc_sbr[T_HUFFMAN_NOISE_3_0DB].table;

  815.         t_lav  = vlc_sbr_lav[T_HUFFMAN_NOISE_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.     }

  819. 

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

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

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

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

  824.         } else {

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

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

  827.                 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);

  828.         }

  829.     }

  830. 

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

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

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

  834. }

  835. 

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

  837.                                GetBitContext *gb,

  838.                           int bs_extension_id, int *num_bits_left)

  839. {

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

  841.     switch (bs_extension_id) {

  842.     case EXTENSION_ID_PS:

  843. #if 0

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

  845. #else

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

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

  848.         *num_bits_left = 0;

  849. #endif

  850.         break;

  851.     default:

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

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

  854.         *num_bits_left = 0;

  855.         break;

  856.     }

  857. }

  858. 

  859. static void read_sbr_single_channel_element(AACContext *ac,

  860.                                             SpectralBandReplication *sbr,

  861.                                             GetBitContext *gb)

  862. {

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

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

  865. 

  866.     read_sbr_grid(ac, sbr, gb, &sbr->data[0]);

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

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

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

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

  871. 

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

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

  874. }

  875. 

  876. static void read_sbr_channel_pair_element(AACContext *ac,

  877.                                           SpectralBandReplication *sbr,

  878.                                           GetBitContext *gb)

  879. {

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

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

  882. 

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

  884.         read_sbr_grid(ac, sbr, gb, &sbr->data[0]);

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

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

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

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

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

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

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

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

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

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

  895.     } else {

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

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

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

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

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

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

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

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

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

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

  906.     }

  907. 

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

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

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

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

  912. }

  913. 

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

  915.                                   GetBitContext *gb, int id_aac)

  916. {

  917.     unsigned int cnt = get_bits_count(gb);

  918. 

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

  920.         read_sbr_single_channel_element(ac, sbr, gb);

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

  922.         read_sbr_channel_pair_element(ac, sbr, gb);

  923.     } else {

  924.         av_log(ac->avccontext, AV_LOG_ERROR,

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

  926.         sbr->start = 0;

  927.         return get_bits_count(gb) - cnt;

  928.     }

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

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

  931.         if (num_bits_left == 15)

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

  933. 

  934.         num_bits_left <<= 3;

  935.         while (num_bits_left > 7) {

  936.             num_bits_left -= 2;

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

  938.         }

  939.     }

  940. 

  941.     return get_bits_count(gb) - cnt;

  942. }

  943. 

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

  945. {

  946.     int err;

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

  948.     if (err >= 0)

  949.         err = sbr_make_f_derived(ac, sbr);

  950.     if (err < 0) {

  951.         av_log(ac->avccontext, AV_LOG_ERROR,

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

  953.         sbr->start = 0;

  954.     }

  955. }

  956. 

  957. /**

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

  959.  *

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

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

  962.  *

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

  964.  */

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

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

  967. {

  968.     unsigned int num_sbr_bits = 0, num_align_bits;

  969.     unsigned bytes_read;

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

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

  972. 

  973.     sbr->reset = 0;

  974. 

  975.     if (!sbr->sample_rate)

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

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

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

  979. 

  980.     if (crc) {

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

  982.         num_sbr_bits += 10;

  983.     }

  984. 

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

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

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

  988. 

  989.     num_sbr_bits++;

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

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

  992. 

  993.     if (sbr->reset)

  994.         sbr_reset(ac, sbr);

  995. 

  996.     if (sbr->start)

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

  998. 

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

  1000.     bytes_read = ((num_sbr_bits + num_align_bits + 4) >> 3);

  1001. 

  1002.     if (bytes_read > cnt) {

  1003.         av_log(ac->avccontext, AV_LOG_ERROR,

  1004.                "Expected to read %d SBR bytes actually read %d.\n", cnt, bytes_read);

  1005.     }

  1006.     return cnt;

  1007. }

  1008. 

  1009. /// Time/frequency Grid (14496-3 sp04 p200)

  1010. static int sbr_time_freq_grid(AACContext *ac, SpectralBandReplication *sbr,

  1011.                               SBRData *ch_data, int ch)

  1012. {

  1013.     int abs_bord_lead  =  ch_data->bs_frame_class >= 2 ? ch_data->bs_var_bord[0] : 0;

  1014.     // frameLengthFlag ? 15 : 16; 960 sample length frames unsupported; this value is numTimeSlots

  1015.     int abs_bord_trail = (ch_data->bs_frame_class & 1 ? ch_data->bs_var_bord[1] : 0) + 16;

  1016.     int n_rel_lead;

  1017.     int i;

  1018. 

  1019.     if (ch_data->bs_frame_class == FIXFIX) {

  1020.         n_rel_lead = ch_data->bs_num_env[1] - 1;

  1021.     } else if (ch_data->bs_frame_class == FIXVAR) {

  1022.         n_rel_lead = 0;

  1023.     } else if (ch_data->bs_frame_class < 4) { // VARFIX or VARVAR

  1024.         n_rel_lead = ch_data->bs_num_rel[0];

  1025.     } else {

  1026.         av_log(ac->avccontext, AV_LOG_ERROR,

  1027.                "Invalid bs_frame_class for SBR: %d\n", ch_data->bs_frame_class);

  1028.         return -1;

  1029.     }

  1030. 

  1031.     ch_data->t_env_num_env_old = ch_data->t_env[ch_data->bs_num_env[0]];

  1032.     ch_data->t_env[0]                      = abs_bord_lead;

  1033.     ch_data->t_env[ch_data->bs_num_env[1]] = abs_bord_trail;

  1034. 

  1035.     if (ch_data->bs_frame_class == FIXFIX) {

  1036.         int temp = (abs_bord_trail + (ch_data->bs_num_env[1] >> 1)) /

  1037.                    ch_data->bs_num_env[1];

  1038.         for (i = 0; i < n_rel_lead; i++)

  1039.             ch_data->t_env[i + 1] = ch_data->t_env[i] + temp;

  1040.     } else if (ch_data->bs_frame_class > 1) { // VARFIX or VARVAR

  1041.         for (i = 0; i < n_rel_lead; i++)

  1042.             ch_data->t_env[i + 1] = ch_data->t_env[i] + ch_data->bs_rel_bord[0][i];

  1043.     } else { // FIXVAR

  1044.         for (i = 0; i < n_rel_lead; i++)

  1045.             ch_data->t_env[i + 1] = abs_bord_lead;

  1046.     }

  1047. 

  1048.     if (ch_data->bs_frame_class & 1) { // FIXVAR or VARVAR

  1049.         for (i = ch_data->bs_num_env[1] - 1; i > n_rel_lead; i--)

  1050.             ch_data->t_env[i] = ch_data->t_env[i + 1] -

  1051.                                 ch_data->bs_rel_bord[1][ch_data->bs_num_env[1] - 1 - i];

  1052.     } else { // FIXFIX or VARFIX

  1053.         for (i = n_rel_lead; i < ch_data->bs_num_env[1]; i++)

  1054.             ch_data->t_env[i + 1] = abs_bord_trail;

  1055.     }

  1056. 

  1057.     ch_data->t_q[0] = ch_data->t_env[0];

  1058.     if (ch_data->bs_num_noise > 1) { // typo in spec bases this on bs_num_env...

  1059.         unsigned int idx;

  1060.         if (ch_data->bs_frame_class == FIXFIX) {

  1061.             idx = ch_data->bs_num_env[1] >> 1;

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

  1063.             idx = ch_data->bs_num_env[1] - FFMAX(ch_data->bs_pointer - 1, 1);

  1064.         } else { // VARFIX

  1065.             if (!ch_data->bs_pointer)

  1066.                 idx = 1;

  1067.             else if (ch_data->bs_pointer == 1)

  1068.                 idx = ch_data->bs_num_env[1] - 1;

  1069.             else // bs_pointer > 1

  1070.                 idx = ch_data->bs_pointer - 1;

  1071.         }

  1072.         ch_data->t_q[1] = ch_data->t_env[idx];

  1073.         ch_data->t_q[2] = ch_data->t_env[ch_data->bs_num_env[1]];

  1074.     } else

  1075.         ch_data->t_q[1] = ch_data->t_env[ch_data->bs_num_env[1]];

  1076. 

  1077.     return 0;

  1078. }

  1079. 

  1080. /// Dequantization and stereo decoding (14496-3 sp04 p203)

  1081. static void sbr_dequant(SpectralBandReplication *sbr, int id_aac)

  1082. {

  1083.     int k, e;

  1084.     int ch;

  1085. 

  1086.     if (id_aac == TYPE_CPE && sbr->bs_coupling) {

  1087.         float alpha      = sbr->data[0].bs_amp_res ?  1.0f :  0.5f;

  1088.         float pan_offset = sbr->data[0].bs_amp_res ? 12.0f : 24.0f;

  1089.         for (e = 1; e <= sbr->data[0].bs_num_env[1]; e++) {

  1090.             for (k = 0; k < sbr->n[sbr->data[0].bs_freq_res[e]]; k++) {

  1091.                 float temp1 = exp2f(sbr->data[0].env_facs[e][k] * alpha + 7.0f);

  1092.                 float temp2 = exp2f((pan_offset - sbr->data[1].env_facs[e][k]) * alpha);

  1093.                 float fac   = temp1 / (1.0f + temp2);

  1094.                 sbr->data[0].env_facs[e][k] = fac;

  1095.                 sbr->data[1].env_facs[e][k] = fac * temp2;

  1096.             }

  1097.         }

  1098.         for (e = 1; e <= sbr->data[0].bs_num_noise; e++) {

  1099.             for (k = 0; k < sbr->n_q; k++) {

  1100.                 float temp1 = exp2f(NOISE_FLOOR_OFFSET - sbr->data[0].noise_facs[e][k] + 1);

  1101.                 float temp2 = exp2f(12 - sbr->data[1].noise_facs[e][k]);

  1102.                 float fac   = temp1 / (1.0f + temp2);

  1103.                 sbr->data[0].noise_facs[e][k] = fac;

  1104.                 sbr->data[1].noise_facs[e][k] = fac * temp2;

  1105.             }

  1106.         }

  1107.     } else { // SCE or one non-coupled CPE

  1108.         for (ch = 0; ch < (id_aac == TYPE_CPE) + 1; ch++) {

  1109.             float alpha = sbr->data[ch].bs_amp_res ? 1.0f : 0.5f;

  1110.             for (e = 1; e <= sbr->data[ch].bs_num_env[1]; e++)

  1111.                 for (k = 0; k < sbr->n[sbr->data[ch].bs_freq_res[e]]; k++)

  1112.                     sbr->data[ch].env_facs[e][k] =

  1113.                         exp2f(alpha * sbr->data[ch].env_facs[e][k] + 6.0f);

  1114.             for (e = 1; e <= sbr->data[ch].bs_num_noise; e++)

  1115.                 for (k = 0; k < sbr->n_q; k++)

  1116.                     sbr->data[ch].noise_facs[e][k] =

  1117.                         exp2f(NOISE_FLOOR_OFFSET - sbr->data[ch].noise_facs[e][k]);

  1118.         }

  1119.     }

  1120. }

  1121. 

  1122. /**

  1123.  * Analysis QMF Bank (14496-3 sp04 p206)

  1124.  *

  1125.  * @param   x       pointer to the beginning of the first sample window

  1126.  * @param   W       array of complex-valued samples split into subbands

  1127.  */

  1128. static void sbr_qmf_analysis(DSPContext *dsp, RDFTContext *rdft, const float *in, float *x,

  1129.                              float z[320], float W[2][32][32][2],

  1130.                              float bias, float scale)

  1131. {

  1132.     int i, k;

  1133.     memcpy(W[0], W[1], sizeof(W[0]));

  1134.     memcpy(x    , x+1024, (320-32)*sizeof(x[0]));

  1135.     if (scale != 1.0f || bias != 0.0f)

  1136.         for (i = 0; i < 1024; i++)

  1137.             x[288 + i] = (in[i] - bias) * scale;

  1138.     else

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

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

  1141.                                // are not supported

  1142.         float re, im;

  1143.         dsp->vector_fmul_reverse(z, sbr_qmf_window_ds, x, 320);

  1144.         for (k = 0; k < 64; k++) {

  1145.             float f = z[k] + z[k + 64] + z[k + 128] + z[k + 192] + z[k + 256];

  1146.             z[k] = f * analysis_cos_pre[k];

  1147.             z[k+64] = f;

  1148.         }

  1149.         ff_rdft_calc(rdft, z);

  1150.         re = z[0] * 0.5f;

  1151.         im = 0.5f * dsp->scalarproduct_float(z+64, analysis_sin_pre, 64);

  1152.         W[1][i][0][0] = re * analysis_cossin_post[0][0] - im * analysis_cossin_post[0][1];

  1153.         W[1][i][0][1] = re * analysis_cossin_post[0][1] + im * analysis_cossin_post[0][0];

  1154.         for (k = 1; k < 32; k++) {

  1155.             re = z[2*k  ] - re;

  1156.             im = z[2*k+1] - im;

  1157.             W[1][i][k][0] = re * analysis_cossin_post[k][0] - im * analysis_cossin_post[k][1];

  1158.             W[1][i][k][1] = re * analysis_cossin_post[k][1] + im * analysis_cossin_post[k][0];

  1159.         }

  1160.         x += 32;

  1161.     }

  1162. }

  1163. 

  1164. /**

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

  1166.  * (14496-3 sp04 p206)

  1167.  */

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

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

  1170.                               float mdct_buf[2][64],

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

  1172.                               float bias, float scale)

  1173. {

  1174.     int i, n;

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

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

  1177.     float *v;

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

  1179.         if (*v_off == 0) {

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

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

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

  1183.         } else {

  1184.             *v_off -= 128 >> div;

  1185.         }

  1186.         v = v0 + *v_off;

  1187.         for (n = 1; n < 64 >> div; n+=2) {

  1188.             X[1][i][n] = -X[1][i][n];

  1189.         }

  1190.         if (div) {

  1191.             memset(X[0][i]+32, 0, 32*sizeof(float));

  1192.             memset(X[1][i]+32, 0, 32*sizeof(float));

  1193.         }

  1194.         ff_imdct_half(mdct, mdct_buf[0], X[0][i]);

  1195.         ff_imdct_half(mdct, mdct_buf[1], X[1][i]);

  1196.         if (div) {

  1197.             for (n = 0; n < 32; n++) {

  1198.                 v[      n] = -mdct_buf[0][63 - 2*n] + mdct_buf[1][2*n    ];

  1199.                 v[ 63 - n] =  mdct_buf[0][62 - 2*n] + mdct_buf[1][2*n + 1];

  1200.             }

  1201.         } else {

  1202.             for (n = 0; n < 64; n++) {

  1203.                 v[      n] = -mdct_buf[0][63 -   n] + mdct_buf[1][  n    ];

  1204.                 v[127 - n] =  mdct_buf[0][63 -   n] + mdct_buf[1][  n    ];

  1205.             }

  1206.         }

  1207.         dsp->vector_fmul_add(out, v                , sbr_qmf_window               , zero64, 64 >> div);

  1208.         dsp->vector_fmul_add(out, v + ( 192 >> div), sbr_qmf_window + ( 64 >> div), out   , 64 >> div);

  1209.         dsp->vector_fmul_add(out, v + ( 256 >> div), sbr_qmf_window + (128 >> div), out   , 64 >> div);

  1210.         dsp->vector_fmul_add(out, v + ( 448 >> div), sbr_qmf_window + (192 >> div), out   , 64 >> div);

  1211.         dsp->vector_fmul_add(out, v + ( 512 >> div), sbr_qmf_window + (256 >> div), out   , 64 >> div);

  1212.         dsp->vector_fmul_add(out, v + ( 704 >> div), sbr_qmf_window + (320 >> div), out   , 64 >> div);

  1213.         dsp->vector_fmul_add(out, v + ( 768 >> div), sbr_qmf_window + (384 >> div), out   , 64 >> div);

  1214.         dsp->vector_fmul_add(out, v + ( 960 >> div), sbr_qmf_window + (448 >> div), out   , 64 >> div);

  1215.         dsp->vector_fmul_add(out, v + (1024 >> div), sbr_qmf_window + (512 >> div), out   , 64 >> div);

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

  1217.         if (scale_and_bias)

  1218.             for (n = 0; n < 64 >> div; n++)

  1219.                 out[n] = out[n] * scale + bias;

  1220.         out += 64 >> div;

  1221.     }

  1222. }

  1223. 

  1224. static void autocorrelate(const float x[40][2], float phi[3][2][2], int lag)

  1225. {

  1226.     int i;

  1227.     float real_sum = 0.0f;

  1228.     float imag_sum = 0.0f;

  1229.     if (lag) {

  1230.         for (i = 1; i < 38; i++) {

  1231.             real_sum += x[i][0] * x[i+lag][0] + x[i][1] * x[i+lag][1];

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

  1233.         }

  1234.         phi[2-lag][1][0] = real_sum + x[ 0][0] * x[lag][0] + x[ 0][1] * x[lag][1];

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

  1236.         if (lag == 1) {

  1237.             phi[0][0][0] = real_sum + x[38][0] * x[39][0] + x[38][1] * x[39][1];

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

  1239.         }

  1240.     } else {

  1241.         for (i = 1; i < 38; i++) {

  1242.             real_sum += x[i][0] * x[i][0] + x[i][1] * x[i][1];

  1243.         }

  1244.         phi[2][1][0] = real_sum + x[ 0][0] * x[ 0][0] + x[ 0][1] * x[ 0][1];

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

  1246.     }

  1247. }

  1248. 

  1249. /** High Frequency Generation (14496-3 sp04 p214+) and Inverse Filtering

  1250.  * (14496-3 sp04 p214)

  1251.  * Warning: This routine does not seem numerically stable.

  1252.  */

  1253. static void sbr_hf_inverse_filter(float (*alpha0)[2], float (*alpha1)[2],

  1254.                                   const float X_low[32][40][2], int k0)

  1255. {

  1256.     int k;

  1257.     for (k = 0; k < k0; k++) {

  1258.         float phi[3][2][2], dk;

  1259. 

  1260.         autocorrelate(X_low[k], phi, 0);

  1261.         autocorrelate(X_low[k], phi, 1);

  1262.         autocorrelate(X_low[k], phi, 2);

  1263. 

  1264.         dk =  phi[2][1][0] * phi[1][0][0] -

  1265.              (phi[1][1][0] * phi[1][1][0] + phi[1][1][1] * phi[1][1][1]) / 1.000001f;

  1266. 

  1267.         if (!dk) {

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

  1269.             alpha1[k][1] = 0;

  1270.         } else {

  1271.             float temp_real, temp_im;

  1272.             temp_real = phi[0][0][0] * phi[1][1][0] -

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

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

  1275.             temp_im   = phi[0][0][0] * phi[1][1][1] +

  1276.                         phi[0][0][1] * phi[1][1][0] -

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

  1278. 

  1279.             alpha1[k][0] = temp_real / dk;

  1280.             alpha1[k][1] = temp_im   / dk;

  1281.         }

  1282. 

  1283.         if (!phi[1][0][0]) {

  1284.             alpha0[k][0] = 0;

  1285.             alpha0[k][1] = 0;

  1286.         } else {

  1287.             float temp_real, temp_im;

  1288.             temp_real = phi[0][0][0] + alpha1[k][0] * phi[1][1][0] +

  1289.                                        alpha1[k][1] * phi[1][1][1];

  1290.             temp_im   = phi[0][0][1] + alpha1[k][1] * phi[1][1][0] -

  1291.                                        alpha1[k][0] * phi[1][1][1];

  1292. 

  1293.             alpha0[k][0] = -temp_real / phi[1][0][0];

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

  1295.         }

  1296. 

  1297.         if (alpha1[k][0] * alpha1[k][0] + alpha1[k][1] * alpha1[k][1] >= 16.0f ||

  1298.            alpha0[k][0] * alpha0[k][0] + alpha0[k][1] * alpha0[k][1] >= 16.0f) {

  1299.             alpha1[k][0] = 0;

  1300.             alpha1[k][1] = 0;

  1301.             alpha0[k][0] = 0;

  1302.             alpha0[k][1] = 0;

  1303.         }

  1304.     }

  1305. }

  1306. 

  1307. /// Chirp Factors (14496-3 sp04 p214)

  1308. static void sbr_chirp(SpectralBandReplication *sbr, SBRData *ch_data)

  1309. {

  1310.     int i;

  1311.     float new_bw;

  1312.     static const float bw_tab[] = { 0.0f, 0.75f, 0.9f, 0.98f };

  1313. 

  1314.     for (i = 0; i < sbr->n_q; i++) {

  1315.         if (ch_data->bs_invf_mode[0][i] + ch_data->bs_invf_mode[1][i] == 1) {

  1316.             new_bw = 0.6f;

  1317.         } else

  1318.             new_bw = bw_tab[ch_data->bs_invf_mode[0][i]];

  1319. 

  1320.         if (new_bw < ch_data->bw_array[i]) {

  1321.             new_bw = 0.75f    * new_bw + 0.25f    * ch_data->bw_array[i];

  1322.         } else

  1323.             new_bw = 0.90625f * new_bw + 0.09375f * ch_data->bw_array[i];

  1324.         ch_data->bw_array[i] = new_bw < 0.015625f ? 0.0f : new_bw;

  1325.     }

  1326. }

  1327. 

  1328. /// Generate the subband filtered lowband

  1329. static int sbr_lf_gen(AACContext *ac, SpectralBandReplication *sbr,

  1330.                       float X_low[32][40][2], const float W[2][32][32][2])

  1331. {

  1332.     int i, k;

  1333.     const int t_HFGen = 8;

  1334.     const int i_f = 32;

  1335.     memset(X_low, 0, 32*sizeof(*X_low));

  1336.     for (k = 0; k < sbr->kx[1]; k++) {

  1337.         for (i = t_HFGen; i < i_f + t_HFGen; i++) {

  1338.             X_low[k][i][0] = W[1][i - t_HFGen][k][0];

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

  1340.         }

  1341.     }

  1342.     for (k = 0; k < sbr->kx[0]; k++) {

  1343.         for (i = 0; i < t_HFGen; i++) {

  1344.             X_low[k][i][0] = W[0][i + i_f - t_HFGen][k][0];

  1345.             X_low[k][i][1] = W[0][i + i_f - t_HFGen][k][1];

  1346.         }

  1347.     }

  1348.     return 0;

  1349. }

  1350. 

  1351. /// High Frequency Generator (14496-3 sp04 p215)

  1352. static int sbr_hf_gen(AACContext *ac, SpectralBandReplication *sbr,

  1353.                       float X_high[64][40][2], const float X_low[32][40][2],

  1354.                       const float (*alpha0)[2], const float (*alpha1)[2],

  1355.                       const float bw_array[5], const uint8_t *t_env,

  1356.                       int bs_num_env)

  1357. {

  1358.     int i, j, x;

  1359.     int g = 0;

  1360.     int k = sbr->kx[1];

  1361.     for (j = 0; j < sbr->num_patches; j++) {

  1362.         for (x = 0; x < sbr->patch_num_subbands[j]; x++, k++) {

  1363.             float alpha[4];

  1364.             const int p = sbr->patch_start_subband[j] + x;

  1365.             while (g <= sbr->n_q && k >= sbr->f_tablenoise[g])

  1366.                 g++;

  1367.             g--;

  1368. 

  1369.             if (g < 0) {

  1370.                 av_log(ac->avccontext, AV_LOG_ERROR,

  1371.                        "ERROR : no subband found for frequency %d\n", k);

  1372.                 return -1;

  1373.             }

  1374. 

  1375.             alpha[0] = alpha1[p][0] * bw_array[g] * bw_array[g];

  1376.             alpha[1] = alpha1[p][1] * bw_array[g] * bw_array[g];

  1377.             alpha[2] = alpha0[p][0] * bw_array[g];

  1378.             alpha[3] = alpha0[p][1] * bw_array[g];

  1379. 

  1380.             for (i = 2 * t_env[0]; i < 2 * t_env[bs_num_env]; i++) {

  1381.                 const int idx = i + ENVELOPE_ADJUSTMENT_OFFSET;

  1382.                 X_high[k][idx][0] =

  1383.                     X_low[p][idx - 2][0] * alpha[0] -

  1384.                     X_low[p][idx - 2][1] * alpha[1] +

  1385.                     X_low[p][idx - 1][0] * alpha[2] -

  1386.                     X_low[p][idx - 1][1] * alpha[3] +

  1387.                     X_low[p][idx][0];

  1388.                 X_high[k][idx][1] =

  1389.                     X_low[p][idx - 2][1] * alpha[0] +

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

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

  1392.                     X_low[p][idx - 1][0] * alpha[3] +

  1393.                     X_low[p][idx][1];

  1394.             }

  1395.         }

  1396.     }

  1397.     if (k < sbr->m[1] + sbr->kx[1])

  1398.         memset(X_high + k, 0, (sbr->m[1] + sbr->kx[1] - k) * sizeof(*X_high));

  1399. 

  1400.     return 0;

  1401. }

  1402. 

  1403. /// Generate the subband filtered lowband

  1404. static int sbr_x_gen(SpectralBandReplication *sbr, float X[2][32][64],

  1405.                      const float X_low[32][40][2], const float Y[2][38][64][2],

  1406.                      int ch)

  1407. {

  1408.     int k, i;

  1409.     const int i_f = 32;

  1410.     const int i_Temp = FFMAX(2*sbr->data[ch].t_env_num_env_old - i_f, 0);

  1411.     memset(X, 0, 2*sizeof(*X));

  1412.     for (k = 0; k < sbr->kx[0]; k++) {

  1413.         for (i = 0; i < i_Temp; i++) {

  1414.             X[0][i][k] = X_low[k][i + ENVELOPE_ADJUSTMENT_OFFSET][0];

  1415.             X[1][i][k] = X_low[k][i + ENVELOPE_ADJUSTMENT_OFFSET][1];

  1416.         }

  1417.     }

  1418.     for (; k < sbr->kx[0] + sbr->m[0]; k++) {

  1419.         for (i = 0; i < i_Temp; i++) {

  1420.             X[0][i][k] = Y[0][i + i_f][k][0];

  1421.             X[1][i][k] = Y[0][i + i_f][k][1];

  1422.         }

  1423.     }

  1424. 

  1425.     for (k = 0; k < sbr->kx[1]; k++) {

  1426.         for (i = i_Temp; i < i_f; i++) {

  1427.             X[0][i][k] = X_low[k][i + ENVELOPE_ADJUSTMENT_OFFSET][0];

  1428.             X[1][i][k] = X_low[k][i + ENVELOPE_ADJUSTMENT_OFFSET][1];

  1429.         }

  1430.     }

  1431.     for (; k < sbr->kx[1] + sbr->m[1]; k++) {

  1432.         for (i = i_Temp; i < i_f; i++) {

  1433.             X[0][i][k] = Y[1][i][k][0];

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

  1435.         }

  1436.     }

  1437.     return 0;

  1438. }

  1439. 

  1440. /** High Frequency Adjustment (14496-3 sp04 p217) and Mapping

  1441.  * (14496-3 sp04 p217)

  1442.  */

  1443. static void sbr_mapping(AACContext *ac, SpectralBandReplication *sbr,

  1444.                         SBRData *ch_data, int e_a[2])

  1445. {

  1446.     int e, i, m;

  1447. 

  1448.     e_a[0] = -(e_a[1] != ch_data->bs_num_env[0]); // l_APrev

  1449.     e_a[1] = -1;

  1450.     if ((ch_data->bs_frame_class & 1) && ch_data->bs_pointer) { // FIXVAR or VARVAR and bs_pointer != 0

  1451.         e_a[1] = ch_data->bs_num_env[1] + 1 - ch_data->bs_pointer;

  1452.     } else if ((ch_data->bs_frame_class == 2) && (ch_data->bs_pointer > 1)) // VARFIX and bs_pointer > 1

  1453.         e_a[1] = ch_data->bs_pointer - 1;

  1454. 

  1455.     memset(ch_data->s_indexmapped[1], 0, 7*sizeof(ch_data->s_indexmapped[1]));

  1456.     for (e = 0; e < ch_data->bs_num_env[1]; e++) {

  1457.         const unsigned int ilim = sbr->n[ch_data->bs_freq_res[e + 1]];

  1458.         uint16_t *table = ch_data->bs_freq_res[e + 1] ? sbr->f_tablehigh : sbr->f_tablelow;

  1459.         int k;

  1460. 

  1461.         for (i = 0; i < ilim; i++)

  1462.             for (m = table[i]; m < table[i + 1]; m++)

  1463.                 sbr->e_origmapped[e][m - sbr->kx[1]] = ch_data->env_facs[e+1][i];

  1464. 

  1465.         // ch_data->bs_num_noise > 1 => 2 noise floors

  1466.         k = (ch_data->bs_num_noise > 1) && (ch_data->t_env[e] >= ch_data->t_q[1]);

  1467.         for (i = 0; i < sbr->n_q; i++)

  1468.             for (m = sbr->f_tablenoise[i]; m < sbr->f_tablenoise[i + 1]; m++)

  1469.                 sbr->q_mapped[e][m - sbr->kx[1]] = ch_data->noise_facs[k+1][i];

  1470. 

  1471.         for (i = 0; i < sbr->n[1]; i++) {

  1472.             if (ch_data->bs_add_harmonic_flag) {

  1473.                 const unsigned int m_midpoint =

  1474.                     (sbr->f_tablehigh[i] + sbr->f_tablehigh[i + 1]) >> 1;

  1475. 

  1476.                 ch_data->s_indexmapped[e + 1][m_midpoint - sbr->kx[1]] = ch_data->bs_add_harmonic[i] *

  1477.                     (e >= e_a[1] || (ch_data->s_indexmapped[0][m_midpoint - sbr->kx[1]] == 1));

  1478.             }

  1479.         }

  1480. 

  1481.         for (i = 0; i < ilim; i++) {

  1482.             int additional_sinusoid_present = 0;

  1483.             for (m = table[i]; m < table[i + 1]; m++) {

  1484.                 if (ch_data->s_indexmapped[e + 1][m - sbr->kx[1]]) {

  1485.                     additional_sinusoid_present = 1;

  1486.                     break;

  1487.                 }

  1488.             }

  1489.             memset(&sbr->s_mapped[e][table[i] - sbr->kx[1]], additional_sinusoid_present,

  1490.                    (table[i + 1] - table[i]) * sizeof(sbr->s_mapped[e][0]));

  1491.         }

  1492.     }

  1493. 

  1494.     memcpy(ch_data->s_indexmapped[0], ch_data->s_indexmapped[ch_data->bs_num_env[1]], sizeof(ch_data->s_indexmapped[0]));

  1495. }

  1496. 

  1497. /// Estimation of current envelope (14496-3 sp04 p218)

  1498. static void sbr_env_estimate(float (*e_curr)[48], float X_high[64][40][2],

  1499.                              SpectralBandReplication *sbr, SBRData *ch_data)

  1500. {

  1501.     int e, i, m;

  1502. 

  1503.     if (sbr->bs_interpol_freq) {

  1504.         for (e = 0; e < ch_data->bs_num_env[1]; e++) {

  1505.             const float recip_env_size = 0.5f / (ch_data->t_env[e + 1] - ch_data->t_env[e]);

  1506.             int ilb = ch_data->t_env[e]     * 2 + ENVELOPE_ADJUSTMENT_OFFSET;

  1507.             int iub = ch_data->t_env[e + 1] * 2 + ENVELOPE_ADJUSTMENT_OFFSET;

  1508. 

  1509.             for (m = 0; m < sbr->m[1]; m++) {

  1510.                 float sum = 0.0f;

  1511. 

  1512.                 for (i = ilb; i < iub; i++) {

  1513.                     sum += X_high[m + sbr->kx[1]][i][0] * X_high[m + sbr->kx[1]][i][0] +

  1514.                            X_high[m + sbr->kx[1]][i][1] * X_high[m + sbr->kx[1]][i][1];

  1515.                 }

  1516.                 e_curr[e][m] = sum * recip_env_size;

  1517.             }

  1518.         }

  1519.     } else {

  1520.         int k, p;

  1521. 

  1522.         for (e = 0; e < ch_data->bs_num_env[1]; e++) {

  1523.             const int env_size = 2 * (ch_data->t_env[e + 1] - ch_data->t_env[e]);

  1524.             int ilb = ch_data->t_env[e]     * 2 + ENVELOPE_ADJUSTMENT_OFFSET;

  1525.             int iub = ch_data->t_env[e + 1] * 2 + ENVELOPE_ADJUSTMENT_OFFSET;

  1526.             const uint16_t *table = ch_data->bs_freq_res[e + 1] ? sbr->f_tablehigh : sbr->f_tablelow;

  1527. 

  1528.             for (p = 0; p < sbr->n[ch_data->bs_freq_res[e + 1]]; p++) {

  1529.                 float sum = 0.0f;

  1530.                 const int den = env_size * (table[p + 1] - table[p]);

  1531. 

  1532.                 for (k = table[p]; k < table[p + 1]; k++) {

  1533.                     for (i = ilb; i < iub; i++) {

  1534.                         sum += X_high[k][i][0] * X_high[k][i][0] +

  1535.                                X_high[k][i][1] * X_high[k][i][1];

  1536.                     }

  1537.                 }

  1538.                 sum /= den;

  1539.                 for (k = table[p]; k < table[p + 1]; k++) {

  1540.                     e_curr[e][k - sbr->kx[1]] = sum;

  1541.                 }

  1542.             }

  1543.         }

  1544.     }

  1545. }

  1546. 

  1547. /**

  1548.  * Calculation of levels of additional HF signal components (14496-3 sp04 p219)

  1549.  * and Calculation of gain (14496-3 sp04 p219)

  1550.  */

  1551. static void sbr_gain_calc(AACContext *ac, SpectralBandReplication *sbr,

  1552.                           SBRData *ch_data, const int e_a[2])

  1553. {

  1554.     int e, k, m;

  1555.     // max gain limits : -3dB, 0dB, 3dB, inf dB (limiter off)

  1556.     static const float limgain[4] = { 0.70795, 1.0, 1.41254, 10000000000 };

  1557. 

  1558.     for (e = 0; e < ch_data->bs_num_env[1]; e++) {

  1559.         int delta = !((e == e_a[1]) || (e == e_a[0]));

  1560.         for (k = 0; k < sbr->n_lim; k++) {

  1561.             float gain_boost, gain_max;

  1562.             float sum[2] = { 0.0f, 0.0f };

  1563.             for (m = sbr->f_tablelim[k] - sbr->kx[1]; m < sbr->f_tablelim[k + 1] - sbr->kx[1]; m++) {

  1564.                 const float temp = sbr->e_origmapped[e][m] / (1.0f + sbr->q_mapped[e][m]);

  1565.                 sbr->q_m[e][m] = sqrtf(temp * sbr->q_mapped[e][m]);

  1566.                 sbr->s_m[e][m] = sqrtf(temp * ch_data->s_indexmapped[e + 1][m]);

  1567.                 if (!sbr->s_mapped[e][m]) {

  1568.                     sbr->gain[e][m] = sqrtf(sbr->e_origmapped[e][m] /

  1569.                                             ((1.0f + sbr->e_curr[e][m]) *

  1570.                                              (1.0f + sbr->q_mapped[e][m] * delta)));

  1571.                 } else {

  1572.                     sbr->gain[e][m] = sqrtf(sbr->e_origmapped[e][m] * sbr->q_mapped[e][m] /

  1573.                                             ((1.0f + sbr->e_curr[e][m]) *

  1574.                                              (1.0f + sbr->q_mapped[e][m])));

  1575.                 }

  1576.             }

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

  1578.                 sum[0] += sbr->e_origmapped[e][m];

  1579.                 sum[1] += sbr->e_curr[e][m];

  1580.             }

  1581.             gain_max = limgain[sbr->bs_limiter_gains] * sqrtf((FLT_EPSILON + sum[0]) / (FLT_EPSILON + sum[1]));

  1582.             gain_max = FFMIN(100000, gain_max);

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

  1584.                 float q_m_max   = sbr->q_m[e][m] * gain_max / sbr->gain[e][m];

  1585.                 sbr->q_m[e][m]  = FFMIN(sbr->q_m[e][m], q_m_max);

  1586.                 sbr->gain[e][m] = FFMIN(sbr->gain[e][m], gain_max);

  1587.             }

  1588.             sum[0] = sum[1] = 0.0f;

  1589.             for (m = sbr->f_tablelim[k] - sbr->kx[1]; m < sbr->f_tablelim[k + 1] - sbr->kx[1]; m++) {

  1590.                 sum[0] += sbr->e_origmapped[e][m];

  1591.                 sum[1] += sbr->e_curr[e][m] * sbr->gain[e][m] * sbr->gain[e][m]

  1592.                           + sbr->s_m[e][m] * sbr->s_m[e][m]

  1593.                           + (delta && !sbr->s_m[e][m]) * sbr->q_m[e][m] * sbr->q_m[e][m];

  1594.             }

  1595.             gain_boost = sqrtf((FLT_EPSILON + sum[0]) / (FLT_EPSILON + sum[1]));

  1596.             gain_boost = FFMIN(1.584893192, gain_boost);

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

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

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

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

  1601.             }

  1602.         }

  1603.     }

  1604. }

  1605. 

  1606. /// Assembling HF Signals (14496-3 sp04 p220)

  1607. static void sbr_hf_assemble(float Y[2][38][64][2], const float X_high[64][40][2],

  1608.                             SpectralBandReplication *sbr, SBRData *ch_data,

  1609.                             const int e_a[2])

  1610. {

  1611.     int e, i, j, m;

  1612.     const int h_SL = 4 * !sbr->bs_smoothing_mode;

  1613.     const int kx = sbr->kx[1];

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

  1615.     static const float h_smooth[5] = {

  1616.         0.33333333333333,

  1617.         0.30150283239582,

  1618.         0.21816949906249,

  1619.         0.11516383427084,

  1620.         0.03183050093751,

  1621.     };

  1622.     static const int8_t phi[2][4] = {

  1623.         {  1,  0, -1,  0}, // real

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

  1625.     };

  1626.     float (*g_temp)[48] = ch_data->g_temp, (*q_temp)[48] = ch_data->q_temp;

  1627.     int indexnoise = ch_data->f_indexnoise;

  1628.     int indexsine  = ch_data->f_indexsine;

  1629.     memcpy(Y[0], Y[1], sizeof(Y[0]));

  1630. 

  1631.     if (sbr->reset) {

  1632.         for (i = 0; i < h_SL; i++) {

  1633.             memcpy(g_temp[i + 2*ch_data->t_env[0]], sbr->gain[0], m_max * sizeof(sbr->gain[0][0]));

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

  1635.         }

  1636.     } else if (h_SL) {

  1637.         memcpy(g_temp[2*ch_data->t_env[0]], g_temp[2*ch_data->t_env_num_env_old], 4*sizeof(g_temp[0]));

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

  1639.     }

  1640. 

  1641.     for (e = 0; e < ch_data->bs_num_env[1]; e++) {

  1642.         for (i = 2 * ch_data->t_env[e]; i < 2 * ch_data->t_env[e + 1]; i++) {

  1643.             memcpy(g_temp[h_SL + i], sbr->gain[e], m_max * sizeof(sbr->gain[0][0]));

  1644.             memcpy(q_temp[h_SL + i], sbr->q_m[e],  m_max * sizeof(sbr->q_m[0][0]));

  1645.         }

  1646.     }

  1647. 

  1648.     for (e = 0; e < ch_data->bs_num_env[1]; e++) {

  1649.         for (i = 2 * ch_data->t_env[e]; i < 2 * ch_data->t_env[e + 1]; i++) {

  1650.             int phi_sign = (1 - 2*(kx & 1));

  1651. 

  1652.             if (h_SL && e != e_a[0] && e != e_a[1]) {

  1653.                 for (m = 0; m < m_max; m++) {

  1654.                     const int idx1 = i + h_SL;

  1655.                     float g_filt = 0.0f;

  1656.                     for (j = 0; j <= h_SL; j++)

  1657.                         g_filt += g_temp[idx1 - j][m] * h_smooth[j];

  1658.                     Y[1][i][m + kx][0] =

  1659.                         X_high[m + kx][i + ENVELOPE_ADJUSTMENT_OFFSET][0] * g_filt;

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

  1661.                         X_high[m + kx][i + ENVELOPE_ADJUSTMENT_OFFSET][1] * g_filt;

  1662.                 }

  1663.             } else {

  1664.                 for (m = 0; m < m_max; m++) {

  1665.                     const float g_filt = g_temp[i + h_SL][m];

  1666.                     Y[1][i][m + kx][0] =

  1667.                         X_high[m + kx][i + ENVELOPE_ADJUSTMENT_OFFSET][0] * g_filt;

  1668.                     Y[1][i][m + kx][1] =

  1669.                         X_high[m + kx][i + ENVELOPE_ADJUSTMENT_OFFSET][1] * g_filt;

  1670.                 }

  1671.             }

  1672. 

  1673.             if (e != e_a[0] && e != e_a[1]) {

  1674.                 for (m = 0; m < m_max; m++) {

  1675.                     indexnoise = (indexnoise + 1) & 0x1ff;

  1676.                     if (sbr->s_m[e][m]) {

  1677.                         Y[1][i][m + kx][0] +=

  1678.                             sbr->s_m[e][m] * phi[0][indexsine];

  1679.                         Y[1][i][m + kx][1] +=

  1680.                             sbr->s_m[e][m] * (phi[1][indexsine] * phi_sign);

  1681.                     } else {

  1682.                         float q_filt;

  1683.                         if (h_SL) {

  1684.                             const int idx1 = i + h_SL;

  1685.                             q_filt = 0.0f;

  1686.                             for (j = 0; j <= h_SL; j++)

  1687.                                 q_filt += q_temp[idx1 - j][m] * h_smooth[j];

  1688.                         } else {

  1689.                             q_filt = q_temp[i][m];

  1690.                         }

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

  1692.                             q_filt * sbr_noise_table[indexnoise][0];

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

  1694.                             q_filt * sbr_noise_table[indexnoise][1];

  1695.                     }

  1696.                     phi_sign = -phi_sign;

  1697.                 }

  1698.             } else {

  1699.                 indexnoise = (indexnoise + m_max) & 0x1ff;

  1700.                 for (m = 0; m < m_max; m++) {

  1701.                     Y[1][i][m + kx][0] +=

  1702.                         sbr->s_m[e][m] * phi[0][indexsine];

  1703.                     Y[1][i][m + kx][1] +=

  1704.                         sbr->s_m[e][m] * (phi[1][indexsine] * phi_sign);

  1705.                     phi_sign = -phi_sign;

  1706.                 }

  1707.             }

  1708.             indexsine = (indexsine + 1) & 3;

  1709.         }

  1710.     }

  1711.     ch_data->f_indexnoise = indexnoise;

  1712.     ch_data->f_indexsine  = indexsine;

  1713. }

  1714. 

  1715. void ff_sbr_dequant(AACContext *ac, SpectralBandReplication *sbr, int id_aac)

  1716. {

  1717.     int ch;

  1718. 

  1719.     if (sbr->start) {

  1720.         for (ch = 0; ch < (id_aac == TYPE_CPE) + 1; ch++) {

  1721.             sbr_time_freq_grid(ac, sbr, &sbr->data[ch], ch);

  1722.         }

  1723.         sbr_dequant(sbr, id_aac);

  1724.     }

  1725. }

  1726. 

  1727. void ff_sbr_apply(AACContext *ac, SpectralBandReplication *sbr, int ch,

  1728.                   const float* in, float* out)

  1729. {

  1730.     int downsampled = ac->m4ac.ext_sample_rate < sbr->sample_rate;

  1731. 

  1732.     /* decode channel */

  1733.     sbr_qmf_analysis(&ac->dsp, &sbr->rdft, in, sbr->data[ch].analysis_filterbank_samples,

  1734.                      (float*)sbr->qmf_filter_scratch,

  1735.                      sbr->data[ch].W, ac->add_bias, 1/(-1024 * ac->sf_scale));

  1736.     sbr_lf_gen(ac, sbr, sbr->X_low, sbr->data[ch].W);

  1737.     if (sbr->start) {

  1738.         sbr_hf_inverse_filter(sbr->alpha0, sbr->alpha1, sbr->X_low, sbr->k[0]);

  1739.         sbr_chirp(sbr, &sbr->data[ch]);

  1740.         sbr_hf_gen(ac, sbr, sbr->X_high, sbr->X_low, sbr->alpha0, sbr->alpha1,

  1741.                    sbr->data[ch].bw_array, sbr->data[ch].t_env,

  1742.                    sbr->data[ch].bs_num_env[1]);

  1743. 

  1744.         // hf_adj

  1745.         sbr_mapping(ac, sbr, &sbr->data[ch], sbr->data[ch].e_a);

  1746.         sbr_env_estimate(sbr->e_curr, sbr->X_high, sbr, &sbr->data[ch]);

  1747.         sbr_gain_calc(ac, sbr, &sbr->data[ch], sbr->data[ch].e_a);

  1748.         sbr_hf_assemble(sbr->data[ch].Y, sbr->X_high, sbr, &sbr->data[ch],

  1749.                         sbr->data[ch].e_a);

  1750.     }

  1751. 

  1752.     /* synthesis */

  1753.     sbr_x_gen(sbr, sbr->X, sbr->X_low, sbr->data[ch].Y, ch);

  1754.     sbr_qmf_synthesis(&ac->dsp, &sbr->mdct, out, sbr->X, sbr->qmf_filter_scratch,

  1755.                       sbr->data[ch].synthesis_filterbank_samples,

  1756.                       &sbr->data[ch].synthesis_filterbank_samples_offset,

  1757.                       downsampled,

  1758.                       ac->add_bias, -1024 * ac->sf_scale);

  1759. }