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FFmpeg/libavcodec/aacsbr.c

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  1. /*

  2.  * AAC Spectral Band Replication decoding functions

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

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

  5.  *

  6.  * This file is part of FFmpeg.

  7.  *

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

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

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

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

  12.  *

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

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

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

  16.  * Lesser General Public License for more details.

  17.  *

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

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

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

  21.  */

  22. 

  23. /**

  24.  * @file

  25.  * AAC Spectral Band Replication decoding functions

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

  27.  */

  28. 

  29. #include "aac.h"

  30. #include "sbr.h"

  31. #include "aacsbr.h"

  32. #include "aacsbrdata.h"

  33. #include "fft.h"

  34. #include "aacps.h"

  35. #include "libavutil/libm.h"

  36. 

  37. #include <stdint.h>

  38. #include <float.h>

  39. #include <math.h>

  40. 

  41. #define ENVELOPE_ADJUSTMENT_OFFSET 2

  42. #define NOISE_FLOOR_OFFSET 6.0f

  43. 

  44. /**

  45.  * SBR VLC tables

  46.  */

  47. enum {

  48.     T_HUFFMAN_ENV_1_5DB,

  49.     F_HUFFMAN_ENV_1_5DB,

  50.     T_HUFFMAN_ENV_BAL_1_5DB,

  51.     F_HUFFMAN_ENV_BAL_1_5DB,

  52.     T_HUFFMAN_ENV_3_0DB,

  53.     F_HUFFMAN_ENV_3_0DB,

  54.     T_HUFFMAN_ENV_BAL_3_0DB,

  55.     F_HUFFMAN_ENV_BAL_3_0DB,

  56.     T_HUFFMAN_NOISE_3_0DB,

  57.     T_HUFFMAN_NOISE_BAL_3_0DB,

  58. };

  59. 

  60. /**

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

  62.  */

  63. enum {

  64.     FIXFIX,

  65.     FIXVAR,

  66.     VARFIX,

  67.     VARVAR,

  68. };

  69. 

  70. enum {

  71.     EXTENSION_ID_PS = 2,

  72. };

  73. 

  74. static VLC vlc_sbr[10];

  75. static const int8_t vlc_sbr_lav[10] =

  76.     { 60, 60, 24, 24, 31, 31, 12, 12, 31, 12 };

  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;

  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 = 1; n < 320; n++)

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

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

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

  123. 

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

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

  126. 

  127.     ff_ps_init();

  128. }

  129. 

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

  131. {

  132.     float mdct_scale;

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

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

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

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

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

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

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

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

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

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

  143.     ff_ps_ctx_init(&sbr->ps);

  144. }

  145. 

  146. av_cold void ff_aac_sbr_ctx_close(SpectralBandReplication *sbr)

  147. {

  148.     ff_mdct_end(&sbr->mdct);

  149.     ff_mdct_end(&sbr->mdct_ana);

  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[7];

  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 *avctx, int n_master, int bs_xover_band)

  295. {

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

  297.     if (n_master <= 0) {

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

  299.         return -1;

  300.     }

  301.     if (bs_xover_band >= n_master) {

  302.         av_log(avctx, 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->avctx, 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->avctx, 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->avctx, 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.         int dk, k2diff;

  390. 

  391.         dk = spectrum->bs_alter_scale + 1;

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

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

  394.             return -1;

  395. 

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

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

  398. 

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

  400.         if (k2diff < 0) {

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

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

  403.         } else if (k2diff) {

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

  405.         }

  406. 

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

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

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

  410. 

  411.     } else {

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

  413.         int two_regions, num_bands_0;

  414.         int vdk0_max, vdk1_min;

  415.         int16_t vk0[49];

  416. 

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

  418.             two_regions = 1;

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

  420.         } else {

  421.             two_regions = 0;

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

  423.         }

  424. 

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

  426. 

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

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

  429.             return -1;

  430.         }

  431. 

  432.         vk0[0] = 0;

  433. 

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

  435. 

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

  437.         vdk0_max = vk0[num_bands_0];

  438. 

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

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

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

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

  443.                 return -1;

  444.             }

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

  446.         }

  447. 

  448.         if (two_regions) {

  449.             int16_t vk1[49];

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

  451.                                                      : 1.0f; // bs_alter_scale = {0,1}

  452.             int num_bands_1 = lrintf(half_bands * invwarp *

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

  454. 

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

  456. 

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

  458. 

  459.             if (vdk1_min < vdk0_max) {

  460.                 int change;

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

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

  463.                 vk1[1]           += change;

  464.                 vk1[num_bands_1] -= change;

  465.             }

  466. 

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

  468. 

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

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

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

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

  473.                     return -1;

  474.                 }

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

  476.             }

  477. 

  478.             sbr->n_master = num_bands_0 + num_bands_1;

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

  480.                 return -1;

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

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

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

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

  485. 

  486.         } else {

  487.             sbr->n_master = num_bands_0;

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

  489.                 return -1;

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

  491.         }

  492.     }

  493. 

  494.     return 0;

  495. }

  496. 

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

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

  499. {

  500.     int i, k, sb = 0;

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

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

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

  504. 

  505.     sbr->num_patches = 0;

  506. 

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

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

  509.     } else

  510.         k = sbr->n_master;

  511. 

  512.     do {

  513.         int odd = 0;

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

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

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

  517.         }

  518. 

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

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

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

  522.         // count of 6 patches

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

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

  525.             return -1;

  526.         }

  527. 

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

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

  530. 

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

  532.             usb = sb;

  533.             msb = sb;

  534.             sbr->num_patches++;

  535.         } else

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

  537. 

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

  539.             k = sbr->n_master;

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

  541. 

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

  543.         sbr->num_patches--;

  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->avctx, 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->avctx, 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->avctx, 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.     unsigned bs_pointer = 0;

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

  622.     int abs_bord_trail = 16;

  623.     int num_rel_lead, num_rel_trail;

  624.     unsigned bs_num_env_old = ch_data->bs_num_env;

  625. 

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

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

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

  629. 

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

  631.     case FIXFIX:

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

  633.         num_rel_lead                        = ch_data->bs_num_env - 1;

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

  635.             ch_data->bs_amp_res = 0;

  636. 

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

  638.             av_log(ac->avctx, AV_LOG_ERROR,

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

  640.                    ch_data->bs_num_env);

  641.             return -1;

  642.         }

  643. 

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

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

  646. 

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

  648.                    ch_data->bs_num_env;

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

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

  651. 

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

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

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

  655.         break;

  656.     case FIXVAR:

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

  658.         num_rel_trail                       = get_bits(gb, 2);

  659.         ch_data->bs_num_env                 = num_rel_trail + 1;

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

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

  662. 

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

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

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

  666. 

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

  668. 

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

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

  671.         break;

  672.     case VARFIX:

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

  674.         num_rel_lead                        = get_bits(gb, 2);

  675.         ch_data->bs_num_env                 = num_rel_lead + 1;

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

  677. 

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

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

  680. 

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

  682. 

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

  684.         break;

  685.     case VARVAR:

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

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

  688.         num_rel_lead                        = get_bits(gb, 2);

  689.         num_rel_trail                       = get_bits(gb, 2);

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

  691. 

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

  693.             av_log(ac->avctx, AV_LOG_ERROR,

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

  695.                    ch_data->bs_num_env);

  696.             return -1;

  697.         }

  698. 

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

  700. 

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

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

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

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

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

  706. 

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

  708. 

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

  710.         break;

  711.     }

  712. 

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

  714.         av_log(ac->avctx, AV_LOG_ERROR,

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

  716.                bs_pointer);

  717.         return -1;

  718.     }

  719. 

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

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

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

  723.             return -1;

  724.         }

  725.     }

  726. 

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

  728. 

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

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

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

  732.         unsigned int idx;

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

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

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

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

  737.         } else { // VARFIX

  738.             if (!bs_pointer)

  739.                 idx = 1;

  740.             else if (bs_pointer == 1)

  741.                 idx = ch_data->bs_num_env - 1;

  742.             else // bs_pointer > 1

  743.                 idx = bs_pointer - 1;

  744.         }

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

  746.     }

  747. 

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

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

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

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

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

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

  754. 

  755.     return 0;

  756. }

  757. 

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

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

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

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

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

  763. 

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

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

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

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

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

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

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

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

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

  773. }

  774. 

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

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

  777.                           SBRData *ch_data)

  778. {

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

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

  781. }

  782. 

  783. /// Read inverse filtering data

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

  785.                           SBRData *ch_data)

  786. {

  787.     int i;

  788. 

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

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

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

  792. }

  793. 

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

  795.                               SBRData *ch_data, int ch)

  796. {

  797.     int bits;

  798.     int i, j, k;

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

  800.     int t_lav, f_lav;

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

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

  803. 

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

  805.         if (ch_data->bs_amp_res) {

  806.             bits   = 5;

  807.             t_huff = vlc_sbr[T_HUFFMAN_ENV_BAL_3_0DB].table;

  808.             t_lav  = vlc_sbr_lav[T_HUFFMAN_ENV_BAL_3_0DB];

  809.             f_huff = vlc_sbr[F_HUFFMAN_ENV_BAL_3_0DB].table;

  810.             f_lav  = vlc_sbr_lav[F_HUFFMAN_ENV_BAL_3_0DB];

  811.         } else {

  812.             bits   = 6;

  813.             t_huff = vlc_sbr[T_HUFFMAN_ENV_BAL_1_5DB].table;

  814.             t_lav  = vlc_sbr_lav[T_HUFFMAN_ENV_BAL_1_5DB];

  815.             f_huff = vlc_sbr[F_HUFFMAN_ENV_BAL_1_5DB].table;

  816.             f_lav  = vlc_sbr_lav[F_HUFFMAN_ENV_BAL_1_5DB];

  817.         }

  818.     } else {

  819.         if (ch_data->bs_amp_res) {

  820.             bits   = 6;

  821.             t_huff = vlc_sbr[T_HUFFMAN_ENV_3_0DB].table;

  822.             t_lav  = vlc_sbr_lav[T_HUFFMAN_ENV_3_0DB];

  823.             f_huff = vlc_sbr[F_HUFFMAN_ENV_3_0DB].table;

  824.             f_lav  = vlc_sbr_lav[F_HUFFMAN_ENV_3_0DB];

  825.         } else {

  826.             bits   = 7;

  827.             t_huff = vlc_sbr[T_HUFFMAN_ENV_1_5DB].table;

  828.             t_lav  = vlc_sbr_lav[T_HUFFMAN_ENV_1_5DB];

  829.             f_huff = vlc_sbr[F_HUFFMAN_ENV_1_5DB].table;

  830.             f_lav  = vlc_sbr_lav[F_HUFFMAN_ENV_1_5DB];

  831.         }

  832.     }

  833. 

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

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

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

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

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

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

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

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

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

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

  844.                 }

  845.             } else {

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

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

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

  849.                 }

  850.             }

  851.         } else {

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

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

  854.                 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);

  855.         }

  856.     }

  857. 

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

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

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

  861. }

  862. 

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

  864.                            SBRData *ch_data, int ch)

  865. {

  866.     int i, j;

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

  868.     int t_lav, f_lav;

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

  870. 

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

  872.         t_huff = vlc_sbr[T_HUFFMAN_NOISE_BAL_3_0DB].table;

  873.         t_lav  = vlc_sbr_lav[T_HUFFMAN_NOISE_BAL_3_0DB];

  874.         f_huff = vlc_sbr[F_HUFFMAN_ENV_BAL_3_0DB].table;

  875.         f_lav  = vlc_sbr_lav[F_HUFFMAN_ENV_BAL_3_0DB];

  876.     } else {

  877.         t_huff = vlc_sbr[T_HUFFMAN_NOISE_3_0DB].table;

  878.         t_lav  = vlc_sbr_lav[T_HUFFMAN_NOISE_3_0DB];

  879.         f_huff = vlc_sbr[F_HUFFMAN_ENV_3_0DB].table;

  880.         f_lav  = vlc_sbr_lav[F_HUFFMAN_ENV_3_0DB];

  881.     }

  882. 

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

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

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

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

  887.         } else {

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

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

  890.                 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);

  891.         }

  892.     }

  893. 

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

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

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

  897. }

  898. 

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

  900.                                GetBitContext *gb,

  901.                                int bs_extension_id, int *num_bits_left)

  902. {

  903.     switch (bs_extension_id) {

  904.     case EXTENSION_ID_PS:

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

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

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

  908.             *num_bits_left = 0;

  909.         } else {

  910. #if 1

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

  912. #else

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

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

  915.             *num_bits_left = 0;

  916. #endif

  917.         }

  918.         break;

  919.     default:

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

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

  922.         *num_bits_left = 0;

  923.         break;

  924.     }

  925. }

  926. 

  927. static int read_sbr_single_channel_element(AACContext *ac,

  928.                                             SpectralBandReplication *sbr,

  929.                                             GetBitContext *gb)

  930. {

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

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

  933. 

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

  935.         return -1;

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

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

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

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

  940. 

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

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

  943. 

  944.     return 0;

  945. }

  946. 

  947. static int read_sbr_channel_pair_element(AACContext *ac,

  948.                                           SpectralBandReplication *sbr,

  949.                                           GetBitContext *gb)

  950. {

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

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

  953. 

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

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

  956.             return -1;

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

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

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

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

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

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

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

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

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

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

  967.     } else {

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

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

  970.             return -1;

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

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

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

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

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

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

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

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

  979.     }

  980. 

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

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

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

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

  985. 

  986.     return 0;

  987. }

  988. 

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

  990.                                   GetBitContext *gb, int id_aac)

  991. {

  992.     unsigned int cnt = get_bits_count(gb);

  993. 

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

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

  996.             sbr->start = 0;

  997.             return get_bits_count(gb) - cnt;

  998.         }

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

  1000.         if (read_sbr_channel_pair_element(ac, sbr, gb)) {

  1001.             sbr->start = 0;

  1002.             return get_bits_count(gb) - cnt;

  1003.         }

  1004.     } else {

  1005.         av_log(ac->avctx, AV_LOG_ERROR,

  1006.             "Invalid bitstream - cannot apply SBR to element type %d\n", id_aac);

  1007.         sbr->start = 0;

  1008.         return get_bits_count(gb) - cnt;

  1009.     }

  1010.     if (get_bits1(gb)) { // bs_extended_data

  1011.         int num_bits_left = get_bits(gb, 4); // bs_extension_size

  1012.         if (num_bits_left == 15)

  1013.             num_bits_left += get_bits(gb, 8); // bs_esc_count

  1014. 

  1015.         num_bits_left <<= 3;

  1016.         while (num_bits_left > 7) {

  1017.             num_bits_left -= 2;

  1018.             read_sbr_extension(ac, sbr, gb, get_bits(gb, 2), &num_bits_left); // bs_extension_id

  1019.         }

  1020.         if (num_bits_left < 0) {

  1021.             av_log(ac->avctx, AV_LOG_ERROR, "SBR Extension over read.\n");

  1022.         }

  1023.         if (num_bits_left > 0)

  1024.             skip_bits(gb, num_bits_left);

  1025.     }

  1026. 

  1027.     return get_bits_count(gb) - cnt;

  1028. }

  1029. 

  1030. static void sbr_reset(AACContext *ac, SpectralBandReplication *sbr)

  1031. {

  1032.     int err;

  1033.     err = sbr_make_f_master(ac, sbr, &sbr->spectrum_params);

  1034.     if (err >= 0)

  1035.         err = sbr_make_f_derived(ac, sbr);

  1036.     if (err < 0) {

  1037.         av_log(ac->avctx, AV_LOG_ERROR,

  1038.                "SBR reset failed. Switching SBR to pure upsampling mode.\n");

  1039.         sbr->start = 0;

  1040.     }

  1041. }

  1042. 

  1043. /**

  1044.  * Decode Spectral Band Replication extension data; reference: table 4.55.

  1045.  *

  1046.  * @param   crc flag indicating the presence of CRC checksum

  1047.  * @param   cnt length of TYPE_FIL syntactic element in bytes

  1048.  *

  1049.  * @return  Returns number of bytes consumed from the TYPE_FIL element.

  1050.  */

  1051. int ff_decode_sbr_extension(AACContext *ac, SpectralBandReplication *sbr,

  1052.                             GetBitContext *gb_host, int crc, int cnt, int id_aac)

  1053. {

  1054.     unsigned int num_sbr_bits = 0, num_align_bits;

  1055.     unsigned bytes_read;

  1056.     GetBitContext gbc = *gb_host, *gb = &gbc;

  1057.     skip_bits_long(gb_host, cnt*8 - 4);

  1058. 

  1059.     sbr->reset = 0;

  1060. 

  1061.     if (!sbr->sample_rate)

  1062.         sbr->sample_rate = 2 * ac->m4ac.sample_rate; //TODO use the nominal sample rate for arbitrary sample rate support

  1063.     if (!ac->m4ac.ext_sample_rate)

  1064.         ac->m4ac.ext_sample_rate = 2 * ac->m4ac.sample_rate;

  1065. 

  1066.     if (crc) {

  1067.         skip_bits(gb, 10); // bs_sbr_crc_bits; TODO - implement CRC check

  1068.         num_sbr_bits += 10;

  1069.     }

  1070. 

  1071.     //Save some state from the previous frame.

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

  1073.     sbr->m[0] = sbr->m[1];

  1074. 

  1075.     num_sbr_bits++;

  1076.     if (get_bits1(gb)) // bs_header_flag

  1077.         num_sbr_bits += read_sbr_header(sbr, gb);

  1078. 

  1079.     if (sbr->reset)

  1080.         sbr_reset(ac, sbr);

  1081. 

  1082.     if (sbr->start)

  1083.         num_sbr_bits  += read_sbr_data(ac, sbr, gb, id_aac);

  1084. 

  1085.     num_align_bits = ((cnt << 3) - 4 - num_sbr_bits) & 7;

  1086.     bytes_read = ((num_sbr_bits + num_align_bits + 4) >> 3);

  1087. 

  1088.     if (bytes_read > cnt) {

  1089.         av_log(ac->avctx, AV_LOG_ERROR,

  1090.                "Expected to read %d SBR bytes actually read %d.\n", cnt, bytes_read);

  1091.     }

  1092.     return cnt;

  1093. }

  1094. 

  1095. /// Dequantization and stereo decoding (14496-3 sp04 p203)

  1096. static void sbr_dequant(SpectralBandReplication *sbr, int id_aac)

  1097. {

  1098.     int k, e;

  1099.     int ch;

  1100. 

  1101.     if (id_aac == TYPE_CPE && sbr->bs_coupling) {

  1102.         float alpha      = sbr->data[0].bs_amp_res ?  1.0f :  0.5f;

  1103.         float pan_offset = sbr->data[0].bs_amp_res ? 12.0f : 24.0f;

  1104.         for (e = 1; e <= sbr->data[0].bs_num_env; e++) {

  1105.             for (k = 0; k < sbr->n[sbr->data[0].bs_freq_res[e]]; k++) {

  1106.                 float temp1 = exp2f(sbr->data[0].env_facs[e][k] * alpha + 7.0f);

  1107.                 float temp2 = exp2f((pan_offset - sbr->data[1].env_facs[e][k]) * alpha);

  1108.                 float fac   = temp1 / (1.0f + temp2);

  1109.                 sbr->data[0].env_facs[e][k] = fac;

  1110.                 sbr->data[1].env_facs[e][k] = fac * temp2;

  1111.             }

  1112.         }

  1113.         for (e = 1; e <= sbr->data[0].bs_num_noise; e++) {

  1114.             for (k = 0; k < sbr->n_q; k++) {

  1115.                 float temp1 = exp2f(NOISE_FLOOR_OFFSET - sbr->data[0].noise_facs[e][k] + 1);

  1116.                 float temp2 = exp2f(12 - sbr->data[1].noise_facs[e][k]);

  1117.                 float fac   = temp1 / (1.0f + temp2);

  1118.                 sbr->data[0].noise_facs[e][k] = fac;

  1119.                 sbr->data[1].noise_facs[e][k] = fac * temp2;

  1120.             }

  1121.         }

  1122.     } else { // SCE or one non-coupled CPE

  1123.         for (ch = 0; ch < (id_aac == TYPE_CPE) + 1; ch++) {

  1124.             float alpha = sbr->data[ch].bs_amp_res ? 1.0f : 0.5f;

  1125.             for (e = 1; e <= sbr->data[ch].bs_num_env; e++)

  1126.                 for (k = 0; k < sbr->n[sbr->data[ch].bs_freq_res[e]]; k++)

  1127.                     sbr->data[ch].env_facs[e][k] =

  1128.                         exp2f(alpha * sbr->data[ch].env_facs[e][k] + 6.0f);

  1129.             for (e = 1; e <= sbr->data[ch].bs_num_noise; e++)

  1130.                 for (k = 0; k < sbr->n_q; k++)

  1131.                     sbr->data[ch].noise_facs[e][k] =

  1132.                         exp2f(NOISE_FLOOR_OFFSET - sbr->data[ch].noise_facs[e][k]);

  1133.         }

  1134.     }

  1135. }

  1136. 

  1137. /**

  1138.  * Analysis QMF Bank (14496-3 sp04 p206)

  1139.  *

  1140.  * @param   x       pointer to the beginning of the first sample window

  1141.  * @param   W       array of complex-valued samples split into subbands

  1142.  */

  1143. static void sbr_qmf_analysis(DSPContext *dsp, FFTContext *mdct, const float *in, float *x,

  1144.                              float z[320], float W[2][32][32][2])

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

  1150.     for (i = 0; i < 32; i++) { // numTimeSlots*RATE = 16*2 as 960 sample frames

  1151.                                // are not supported

  1152.         dsp->vector_fmul_reverse(z, sbr_qmf_window_ds, x, 320);

  1153.         for (k = 0; k < 64; k++) {

  1154.             float f = z[k] + z[k + 64] + z[k + 128] + z[k + 192] + z[k + 256];

  1155.             z[k] = f;

  1156.         }

  1157.         //Shuffle to IMDCT

  1158.         z[64] = z[0];

  1159.         for (k = 1; k < 32; k++) {

  1160.             z[64+2*k-1] =  z[   k];

  1161.             z[64+2*k  ] = -z[64-k];

  1162.         }

  1163.         z[64+63] = z[32];

  1164. 

  1165.         mdct->imdct_half(mdct, z, z+64);

  1166.         for (k = 0; k < 32; k++) {

  1167.             W[1][i][k][0] = -z[63-k];

  1168.             W[1][i][k][1] = z[k];

  1169.         }

  1170.         x += 32;

  1171.     }

  1172. }

  1173. 

  1174. /**

  1175.  * Synthesis QMF Bank (14496-3 sp04 p206) and Downsampled Synthesis QMF Bank

  1176.  * (14496-3 sp04 p206)

  1177.  */

  1178. static void sbr_qmf_synthesis(DSPContext *dsp, FFTContext *mdct,

  1179.                               float *out, float X[2][38][64],

  1180.                               float mdct_buf[2][64],

  1181.                               float *v0, int *v_off, const unsigned int div)

  1182. {

  1183.     int i, n;

  1184.     const float *sbr_qmf_window = div ? sbr_qmf_window_ds : sbr_qmf_window_us;

  1185.     float *v;

  1186.     for (i = 0; i < 32; i++) {

  1187.         if (*v_off == 0) {

  1188.             int saved_samples = (1280 - 128) >> div;

  1189.             memcpy(&v0[SBR_SYNTHESIS_BUF_SIZE - saved_samples], v0, saved_samples * sizeof(float));

  1190.             *v_off = SBR_SYNTHESIS_BUF_SIZE - saved_samples - (128 >> div);

  1191.         } else {

  1192.             *v_off -= 128 >> div;

  1193.         }

  1194.         v = v0 + *v_off;

  1195.         if (div) {

  1196.             for (n = 0; n < 32; n++) {

  1197.                 X[0][i][   n] = -X[0][i][n];

  1198.                 X[0][i][32+n] =  X[1][i][31-n];

  1199.             }

  1200.             mdct->imdct_half(mdct, mdct_buf[0], X[0][i]);

  1201.             for (n = 0; n < 32; n++) {

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

  1203.                 v[63 - n] = -mdct_buf[0][62 - 2*n];

  1204.             }

  1205.         } else {

  1206.             for (n = 1; n < 64; n+=2) {

  1207.                 X[1][i][n] = -X[1][i][n];

  1208.             }

  1209.             mdct->imdct_half(mdct, mdct_buf[0], X[0][i]);

  1210.             mdct->imdct_half(mdct, mdct_buf[1], X[1][i]);

  1211.             for (n = 0; n < 64; n++) {

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

  1213.                 v[127 - n] =  mdct_buf[0][63 -   n] + mdct_buf[1][  n    ];

  1214.             }

  1215.         }

  1216.         dsp->vector_fmul_add(out, v                , sbr_qmf_window               , zero64, 64 >> div);

  1217.         dsp->vector_fmul_add(out, v + ( 192 >> div), sbr_qmf_window + ( 64 >> div), out   , 64 >> div);

  1218.         dsp->vector_fmul_add(out, v + ( 256 >> div), sbr_qmf_window + (128 >> div), out   , 64 >> div);

  1219.         dsp->vector_fmul_add(out, v + ( 448 >> div), sbr_qmf_window + (192 >> div), out   , 64 >> div);

  1220.         dsp->vector_fmul_add(out, v + ( 512 >> div), sbr_qmf_window + (256 >> div), out   , 64 >> div);

  1221.         dsp->vector_fmul_add(out, v + ( 704 >> div), sbr_qmf_window + (320 >> div), out   , 64 >> div);

  1222.         dsp->vector_fmul_add(out, v + ( 768 >> div), sbr_qmf_window + (384 >> div), out   , 64 >> div);

  1223.         dsp->vector_fmul_add(out, v + ( 960 >> div), sbr_qmf_window + (448 >> div), out   , 64 >> div);

  1224.         dsp->vector_fmul_add(out, v + (1024 >> div), sbr_qmf_window + (512 >> div), out   , 64 >> div);

  1225.         dsp->vector_fmul_add(out, v + (1216 >> div), sbr_qmf_window + (576 >> div), out   , 64 >> div);

  1226.         out += 64 >> div;

  1227.     }

  1228. }

  1229. 

  1230. static void autocorrelate(const float x[40][2], float phi[3][2][2], int lag)

  1231. {

  1232.     int i;

  1233.     float real_sum = 0.0f;

  1234.     float imag_sum = 0.0f;

  1235.     if (lag) {

  1236.         for (i = 1; i < 38; i++) {

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

  1238.             imag_sum += x[i][0] * x[i+lag][1] - x[i][1] * x[i+lag][0];

  1239.         }

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

  1241.         phi[2-lag][1][1] = imag_sum + x[ 0][0] * x[lag][1] - x[ 0][1] * x[lag][0];

  1242.         if (lag == 1) {

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

  1244.             phi[0][0][1] = imag_sum + x[38][0] * x[39][1] - x[38][1] * x[39][0];

  1245.         }

  1246.     } else {

  1247.         for (i = 1; i < 38; i++) {

  1248.             real_sum += x[i][0] * x[i][0] + x[i][1] * x[i][1];

  1249.         }

  1250.         phi[2][1][0] = real_sum + x[ 0][0] * x[ 0][0] + x[ 0][1] * x[ 0][1];

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

  1252.     }

  1253. }

  1254. 

  1255. /** High Frequency Generation (14496-3 sp04 p214+) and Inverse Filtering

  1256.  * (14496-3 sp04 p214)

  1257.  * Warning: This routine does not seem numerically stable.

  1258.  */

  1259. static void sbr_hf_inverse_filter(float (*alpha0)[2], float (*alpha1)[2],

  1260.                                   const float X_low[32][40][2], int k0)

  1261. {

  1262.     int k;

  1263.     for (k = 0; k < k0; k++) {

  1264.         float phi[3][2][2], dk;

  1265. 

  1266.         autocorrelate(X_low[k], phi, 0);

  1267.         autocorrelate(X_low[k], phi, 1);

  1268.         autocorrelate(X_low[k], phi, 2);

  1269. 

  1270.         dk =  phi[2][1][0] * phi[1][0][0] -

  1271.              (phi[1][1][0] * phi[1][1][0] + phi[1][1][1] * phi[1][1][1]) / 1.000001f;

  1272. 

  1273.         if (!dk) {

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

  1275.             alpha1[k][1] = 0;

  1276.         } else {

  1277.             float temp_real, temp_im;

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

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

  1280.                         phi[0][1][0] * phi[1][0][0];

  1281.             temp_im   = phi[0][0][0] * phi[1][1][1] +

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

  1283.                         phi[0][1][1] * phi[1][0][0];

  1284. 

  1285.             alpha1[k][0] = temp_real / dk;

  1286.             alpha1[k][1] = temp_im   / dk;

  1287.         }

  1288. 

  1289.         if (!phi[1][0][0]) {

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

  1291.             alpha0[k][1] = 0;

  1292.         } else {

  1293.             float temp_real, temp_im;

  1294.             temp_real = phi[0][0][0] + alpha1[k][0] * phi[1][1][0] +

  1295.                                        alpha1[k][1] * phi[1][1][1];

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

  1297.                                        alpha1[k][0] * phi[1][1][1];

  1298. 

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

  1300.             alpha0[k][1] = -temp_im   / phi[1][0][0];

  1301.         }

  1302. 

  1303.         if (alpha1[k][0] * alpha1[k][0] + alpha1[k][1] * alpha1[k][1] >= 16.0f ||

  1304.            alpha0[k][0] * alpha0[k][0] + alpha0[k][1] * alpha0[k][1] >= 16.0f) {

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

  1306.             alpha1[k][1] = 0;

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

  1308.             alpha0[k][1] = 0;

  1309.         }

  1310.     }

  1311. }

  1312. 

  1313. /// Chirp Factors (14496-3 sp04 p214)

  1314. static void sbr_chirp(SpectralBandReplication *sbr, SBRData *ch_data)

  1315. {

  1316.     int i;

  1317.     float new_bw;

  1318.     static const float bw_tab[] = { 0.0f, 0.75f, 0.9f, 0.98f };

  1319. 

  1320.     for (i = 0; i < sbr->n_q; i++) {

  1321.         if (ch_data->bs_invf_mode[0][i] + ch_data->bs_invf_mode[1][i] == 1) {

  1322.             new_bw = 0.6f;

  1323.         } else

  1324.             new_bw = bw_tab[ch_data->bs_invf_mode[0][i]];

  1325. 

  1326.         if (new_bw < ch_data->bw_array[i]) {

  1327.             new_bw = 0.75f    * new_bw + 0.25f    * ch_data->bw_array[i];

  1328.         } else

  1329.             new_bw = 0.90625f * new_bw + 0.09375f * ch_data->bw_array[i];

  1330.         ch_data->bw_array[i] = new_bw < 0.015625f ? 0.0f : new_bw;

  1331.     }

  1332. }

  1333. 

  1334. /// Generate the subband filtered lowband

  1335. static int sbr_lf_gen(AACContext *ac, SpectralBandReplication *sbr,

  1336.                       float X_low[32][40][2], const float W[2][32][32][2])

  1337. {

  1338.     int i, k;

  1339.     const int t_HFGen = 8;

  1340.     const int i_f = 32;

  1341.     memset(X_low, 0, 32*sizeof(*X_low));

  1342.     for (k = 0; k < sbr->kx[1]; k++) {

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

  1344.             X_low[k][i][0] = W[1][i - t_HFGen][k][0];

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

  1346.         }

  1347.     }

  1348.     for (k = 0; k < sbr->kx[0]; k++) {

  1349.         for (i = 0; i < t_HFGen; i++) {

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

  1351.             X_low[k][i][1] = W[0][i + i_f - t_HFGen][k][1];

  1352.         }

  1353.     }

  1354.     return 0;

  1355. }

  1356. 

  1357. /// High Frequency Generator (14496-3 sp04 p215)

  1358. static int sbr_hf_gen(AACContext *ac, SpectralBandReplication *sbr,

  1359.                       float X_high[64][40][2], const float X_low[32][40][2],

  1360.                       const float (*alpha0)[2], const float (*alpha1)[2],

  1361.                       const float bw_array[5], const uint8_t *t_env,

  1362.                       int bs_num_env)

  1363. {

  1364.     int i, j, x;

  1365.     int g = 0;

  1366.     int k = sbr->kx[1];

  1367.     for (j = 0; j < sbr->num_patches; j++) {

  1368.         for (x = 0; x < sbr->patch_num_subbands[j]; x++, k++) {

  1369.             float alpha[4];

  1370.             const int p = sbr->patch_start_subband[j] + x;

  1371.             while (g <= sbr->n_q && k >= sbr->f_tablenoise[g])

  1372.                 g++;

  1373.             g--;

  1374. 

  1375.             if (g < 0) {

  1376.                 av_log(ac->avctx, AV_LOG_ERROR,

  1377.                        "ERROR : no subband found for frequency %d\n", k);

  1378.                 return -1;

  1379.             }

  1380. 

  1381.             alpha[0] = alpha1[p][0] * bw_array[g] * bw_array[g];

  1382.             alpha[1] = alpha1[p][1] * bw_array[g] * bw_array[g];

  1383.             alpha[2] = alpha0[p][0] * bw_array[g];

  1384.             alpha[3] = alpha0[p][1] * bw_array[g];

  1385. 

  1386.             for (i = 2 * t_env[0]; i < 2 * t_env[bs_num_env]; i++) {

  1387.                 const int idx = i + ENVELOPE_ADJUSTMENT_OFFSET;

  1388.                 X_high[k][idx][0] =

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

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

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

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

  1393.                     X_low[p][idx][0];

  1394.                 X_high[k][idx][1] =

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

  1396.                     X_low[p][idx - 2][0] * alpha[1] +

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

  1398.                     X_low[p][idx - 1][0] * alpha[3] +

  1399.                     X_low[p][idx][1];

  1400.             }

  1401.         }

  1402.     }

  1403.     if (k < sbr->m[1] + sbr->kx[1])

  1404.         memset(X_high + k, 0, (sbr->m[1] + sbr->kx[1] - k) * sizeof(*X_high));

  1405. 

  1406.     return 0;

  1407. }

  1408. 

  1409. /// Generate the subband filtered lowband

  1410. static int sbr_x_gen(SpectralBandReplication *sbr, float X[2][38][64],

  1411.                      const float X_low[32][40][2], const float Y[2][38][64][2],

  1412.                      int ch)

  1413. {

  1414.     int k, i;

  1415.     const int i_f = 32;

  1416.     const int i_Temp = FFMAX(2*sbr->data[ch].t_env_num_env_old - i_f, 0);

  1417.     memset(X, 0, 2*sizeof(*X));

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

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

  1420.             X[0][i][k] = X_low[k][i + ENVELOPE_ADJUSTMENT_OFFSET][0];

  1421.             X[1][i][k] = X_low[k][i + ENVELOPE_ADJUSTMENT_OFFSET][1];

  1422.         }

  1423.     }

  1424.     for (; k < sbr->kx[0] + sbr->m[0]; k++) {

  1425.         for (i = 0; i < i_Temp; i++) {

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

  1427.             X[1][i][k] = Y[0][i + i_f][k][1];

  1428.         }

  1429.     }

  1430. 

  1431.     for (k = 0; k < sbr->kx[1]; k++) {

  1432.         for (i = i_Temp; i < 38; i++) {

  1433.             X[0][i][k] = X_low[k][i + ENVELOPE_ADJUSTMENT_OFFSET][0];

  1434.             X[1][i][k] = X_low[k][i + ENVELOPE_ADJUSTMENT_OFFSET][1];

  1435.         }

  1436.     }

  1437.     for (; k < sbr->kx[1] + sbr->m[1]; k++) {

  1438.         for (i = i_Temp; i < i_f; i++) {

  1439.             X[0][i][k] = Y[1][i][k][0];

  1440.             X[1][i][k] = Y[1][i][k][1];

  1441.         }

  1442.     }

  1443.     return 0;

  1444. }

  1445. 

  1446. /** High Frequency Adjustment (14496-3 sp04 p217) and Mapping

  1447.  * (14496-3 sp04 p217)

  1448.  */

  1449. static void sbr_mapping(AACContext *ac, SpectralBandReplication *sbr,

  1450.                         SBRData *ch_data, int e_a[2])

  1451. {

  1452.     int e, i, m;

  1453. 

  1454.     memset(ch_data->s_indexmapped[1], 0, 7*sizeof(ch_data->s_indexmapped[1]));

  1455.     for (e = 0; e < ch_data->bs_num_env; e++) {

  1456.         const unsigned int ilim = sbr->n[ch_data->bs_freq_res[e + 1]];

  1457.         uint16_t *table = ch_data->bs_freq_res[e + 1] ? sbr->f_tablehigh : sbr->f_tablelow;

  1458.         int k;

  1459. 

  1460.         for (i = 0; i < ilim; i++)

  1461.             for (m = table[i]; m < table[i + 1]; m++)

  1462.                 sbr->e_origmapped[e][m - sbr->kx[1]] = ch_data->env_facs[e+1][i];

  1463. 

  1464.         // ch_data->bs_num_noise > 1 => 2 noise floors

  1465.         k = (ch_data->bs_num_noise > 1) && (ch_data->t_env[e] >= ch_data->t_q[1]);

  1466.         for (i = 0; i < sbr->n_q; i++)

  1467.             for (m = sbr->f_tablenoise[i]; m < sbr->f_tablenoise[i + 1]; m++)

  1468.                 sbr->q_mapped[e][m - sbr->kx[1]] = ch_data->noise_facs[k+1][i];

  1469. 

  1470.         for (i = 0; i < sbr->n[1]; i++) {

  1471.             if (ch_data->bs_add_harmonic_flag) {

  1472.                 const unsigned int m_midpoint =

  1473.                     (sbr->f_tablehigh[i] + sbr->f_tablehigh[i + 1]) >> 1;

  1474. 

  1475.                 ch_data->s_indexmapped[e + 1][m_midpoint - sbr->kx[1]] = ch_data->bs_add_harmonic[i] *

  1476.                     (e >= e_a[1] || (ch_data->s_indexmapped[0][m_midpoint - sbr->kx[1]] == 1));

  1477.             }

  1478.         }

  1479. 

  1480.         for (i = 0; i < ilim; i++) {

  1481.             int additional_sinusoid_present = 0;

  1482.             for (m = table[i]; m < table[i + 1]; m++) {

  1483.                 if (ch_data->s_indexmapped[e + 1][m - sbr->kx[1]]) {

  1484.                     additional_sinusoid_present = 1;

  1485.                     break;

  1486.                 }

  1487.             }

  1488.             memset(&sbr->s_mapped[e][table[i] - sbr->kx[1]], additional_sinusoid_present,

  1489.                    (table[i + 1] - table[i]) * sizeof(sbr->s_mapped[e][0]));

  1490.         }

  1491.     }

  1492. 

  1493.     memcpy(ch_data->s_indexmapped[0], ch_data->s_indexmapped[ch_data->bs_num_env], sizeof(ch_data->s_indexmapped[0]));

  1494. }

  1495. 

  1496. /// Estimation of current envelope (14496-3 sp04 p218)

  1497. static void sbr_env_estimate(float (*e_curr)[48], float X_high[64][40][2],

  1498.                              SpectralBandReplication *sbr, SBRData *ch_data)

  1499. {

  1500.     int e, i, m;

  1501. 

  1502.     if (sbr->bs_interpol_freq) {

  1503.         for (e = 0; e < ch_data->bs_num_env; e++) {

  1504.             const float recip_env_size = 0.5f / (ch_data->t_env[e + 1] - ch_data->t_env[e]);

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

  1506.             int iub = ch_data->t_env[e + 1] * 2 + ENVELOPE_ADJUSTMENT_OFFSET;

  1507. 

  1508.             for (m = 0; m < sbr->m[1]; m++) {

  1509.                 float sum = 0.0f;

  1510. 

  1511.                 for (i = ilb; i < iub; i++) {

  1512.                     sum += X_high[m + sbr->kx[1]][i][0] * X_high[m + sbr->kx[1]][i][0] +

  1513.                            X_high[m + sbr->kx[1]][i][1] * X_high[m + sbr->kx[1]][i][1];

  1514.                 }

  1515.                 e_curr[e][m] = sum * recip_env_size;

  1516.             }

  1517.         }

  1518.     } else {

  1519.         int k, p;

  1520. 

  1521.         for (e = 0; e < ch_data->bs_num_env; e++) {

  1522.             const int env_size = 2 * (ch_data->t_env[e + 1] - ch_data->t_env[e]);

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

  1524.             int iub = ch_data->t_env[e + 1] * 2 + ENVELOPE_ADJUSTMENT_OFFSET;

  1525.             const uint16_t *table = ch_data->bs_freq_res[e + 1] ? sbr->f_tablehigh : sbr->f_tablelow;

  1526. 

  1527.             for (p = 0; p < sbr->n[ch_data->bs_freq_res[e + 1]]; p++) {

  1528.                 float sum = 0.0f;

  1529.                 const int den = env_size * (table[p + 1] - table[p]);

  1530. 

  1531.                 for (k = table[p]; k < table[p + 1]; k++) {

  1532.                     for (i = ilb; i < iub; i++) {

  1533.                         sum += X_high[k][i][0] * X_high[k][i][0] +

  1534.                                X_high[k][i][1] * X_high[k][i][1];

  1535.                     }

  1536.                 }

  1537.                 sum /= den;

  1538.                 for (k = table[p]; k < table[p + 1]; k++) {

  1539.                     e_curr[e][k - sbr->kx[1]] = sum;

  1540.                 }

  1541.             }

  1542.         }

  1543.     }

  1544. }

  1545. 

  1546. /**

  1547.  * Calculation of levels of additional HF signal components (14496-3 sp04 p219)

  1548.  * and Calculation of gain (14496-3 sp04 p219)

  1549.  */

  1550. static void sbr_gain_calc(AACContext *ac, SpectralBandReplication *sbr,

  1551.                           SBRData *ch_data, const int e_a[2])

  1552. {

  1553.     int e, k, m;

  1554.     // max gain limits : -3dB, 0dB, 3dB, inf dB (limiter off)

  1555.     static const float limgain[4] = { 0.70795, 1.0, 1.41254, 10000000000 };

  1556. 

  1557.     for (e = 0; e < ch_data->bs_num_env; e++) {

  1558.         int delta = !((e == e_a[1]) || (e == e_a[0]));

  1559.         for (k = 0; k < sbr->n_lim; k++) {

  1560.             float gain_boost, gain_max;

  1561.             float sum[2] = { 0.0f, 0.0f };

  1562.             for (m = sbr->f_tablelim[k] - sbr->kx[1]; m < sbr->f_tablelim[k + 1] - sbr->kx[1]; m++) {

  1563.                 const float temp = sbr->e_origmapped[e][m] / (1.0f + sbr->q_mapped[e][m]);

  1564.                 sbr->q_m[e][m] = sqrtf(temp * sbr->q_mapped[e][m]);

  1565.                 sbr->s_m[e][m] = sqrtf(temp * ch_data->s_indexmapped[e + 1][m]);

  1566.                 if (!sbr->s_mapped[e][m]) {

  1567.                     sbr->gain[e][m] = sqrtf(sbr->e_origmapped[e][m] /

  1568.                                             ((1.0f + sbr->e_curr[e][m]) *

  1569.                                              (1.0f + sbr->q_mapped[e][m] * delta)));

  1570.                 } else {

  1571.                     sbr->gain[e][m] = sqrtf(sbr->e_origmapped[e][m] * sbr->q_mapped[e][m] /

  1572.                                             ((1.0f + sbr->e_curr[e][m]) *

  1573.                                              (1.0f + sbr->q_mapped[e][m])));

  1574.                 }

  1575.             }

  1576.             for (m = sbr->f_tablelim[k] - sbr->kx[1]; m < sbr->f_tablelim[k + 1] - sbr->kx[1]; m++) {

  1577.                 sum[0] += sbr->e_origmapped[e][m];

  1578.                 sum[1] += sbr->e_curr[e][m];

  1579.             }

  1580.             gain_max = limgain[sbr->bs_limiter_gains] * sqrtf((FLT_EPSILON + sum[0]) / (FLT_EPSILON + sum[1]));

  1581.             gain_max = FFMIN(100000.f, gain_max);

  1582.             for (m = sbr->f_tablelim[k] - sbr->kx[1]; m < sbr->f_tablelim[k + 1] - sbr->kx[1]; m++) {

  1583.                 float q_m_max   = sbr->q_m[e][m] * gain_max / sbr->gain[e][m];

  1584.                 sbr->q_m[e][m]  = FFMIN(sbr->q_m[e][m], q_m_max);

  1585.                 sbr->gain[e][m] = FFMIN(sbr->gain[e][m], gain_max);

  1586.             }

  1587.             sum[0] = sum[1] = 0.0f;

  1588.             for (m = sbr->f_tablelim[k] - sbr->kx[1]; m < sbr->f_tablelim[k + 1] - sbr->kx[1]; m++) {

  1589.                 sum[0] += sbr->e_origmapped[e][m];

  1590.                 sum[1] += sbr->e_curr[e][m] * sbr->gain[e][m] * sbr->gain[e][m]

  1591.                           + sbr->s_m[e][m] * sbr->s_m[e][m]

  1592.                           + (delta && !sbr->s_m[e][m]) * sbr->q_m[e][m] * sbr->q_m[e][m];

  1593.             }

  1594.             gain_boost = sqrtf((FLT_EPSILON + sum[0]) / (FLT_EPSILON + sum[1]));

  1595.             gain_boost = FFMIN(1.584893192f, gain_boost);

  1596.             for (m = sbr->f_tablelim[k] - sbr->kx[1]; m < sbr->f_tablelim[k + 1] - sbr->kx[1]; m++) {

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

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

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

  1600.             }

  1601.         }

  1602.     }

  1603. }

  1604. 

  1605. /// Assembling HF Signals (14496-3 sp04 p220)

  1606. static void sbr_hf_assemble(float Y[2][38][64][2], const float X_high[64][40][2],

  1607.                             SpectralBandReplication *sbr, SBRData *ch_data,

  1608.                             const int e_a[2])

  1609. {

  1610.     int e, i, j, m;

  1611.     const int h_SL = 4 * !sbr->bs_smoothing_mode;

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

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

  1614.     static const float h_smooth[5] = {

  1615.         0.33333333333333,

  1616.         0.30150283239582,

  1617.         0.21816949906249,

  1618.         0.11516383427084,

  1619.         0.03183050093751,

  1620.     };

  1621.     static const int8_t phi[2][4] = {

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

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

  1624.     };

  1625.     float (*g_temp)[48] = ch_data->g_temp, (*q_temp)[48] = ch_data->q_temp;

  1626.     int indexnoise = ch_data->f_indexnoise;

  1627.     int indexsine  = ch_data->f_indexsine;

  1628.     memcpy(Y[0], Y[1], sizeof(Y[0]));

  1629. 

  1630.     if (sbr->reset) {

  1631.         for (i = 0; i < h_SL; i++) {

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

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

  1634.         }

  1635.     } else if (h_SL) {

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

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

  1638.     }

  1639. 

  1640.     for (e = 0; e < ch_data->bs_num_env; e++) {

  1641.         for (i = 2 * ch_data->t_env[e]; i < 2 * ch_data->t_env[e + 1]; i++) {

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

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

  1644.         }

  1645.     }

  1646. 

  1647.     for (e = 0; e < ch_data->bs_num_env; e++) {

  1648.         for (i = 2 * ch_data->t_env[e]; i < 2 * ch_data->t_env[e + 1]; i++) {

  1649.             int phi_sign = (1 - 2*(kx & 1));

  1650. 

  1651.             if (h_SL && e != e_a[0] && e != e_a[1]) {

  1652.                 for (m = 0; m < m_max; m++) {

  1653.                     const int idx1 = i + h_SL;

  1654.                     float g_filt = 0.0f;

  1655.                     for (j = 0; j <= h_SL; j++)

  1656.                         g_filt += g_temp[idx1 - j][m] * h_smooth[j];

  1657.                     Y[1][i][m + kx][0] =

  1658.                         X_high[m + kx][i + ENVELOPE_ADJUSTMENT_OFFSET][0] * g_filt;

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

  1660.                         X_high[m + kx][i + ENVELOPE_ADJUSTMENT_OFFSET][1] * g_filt;

  1661.                 }

  1662.             } else {

  1663.                 for (m = 0; m < m_max; m++) {

  1664.                     const float g_filt = g_temp[i + h_SL][m];

  1665.                     Y[1][i][m + kx][0] =

  1666.                         X_high[m + kx][i + ENVELOPE_ADJUSTMENT_OFFSET][0] * g_filt;

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

  1668.                         X_high[m + kx][i + ENVELOPE_ADJUSTMENT_OFFSET][1] * g_filt;

  1669.                 }

  1670.             }

  1671. 

  1672.             if (e != e_a[0] && e != e_a[1]) {

  1673.                 for (m = 0; m < m_max; m++) {

  1674.                     indexnoise = (indexnoise + 1) & 0x1ff;

  1675.                     if (sbr->s_m[e][m]) {

  1676.                         Y[1][i][m + kx][0] +=

  1677.                             sbr->s_m[e][m] * phi[0][indexsine];

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

  1679.                             sbr->s_m[e][m] * (phi[1][indexsine] * phi_sign);

  1680.                     } else {

  1681.                         float q_filt;

  1682.                         if (h_SL) {

  1683.                             const int idx1 = i + h_SL;

  1684.                             q_filt = 0.0f;

  1685.                             for (j = 0; j <= h_SL; j++)

  1686.                                 q_filt += q_temp[idx1 - j][m] * h_smooth[j];

  1687.                         } else {

  1688.                             q_filt = q_temp[i][m];

  1689.                         }

  1690.                         Y[1][i][m + kx][0] +=

  1691.                             q_filt * sbr_noise_table[indexnoise][0];

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

  1693.                             q_filt * sbr_noise_table[indexnoise][1];

  1694.                     }

  1695.                     phi_sign = -phi_sign;

  1696.                 }

  1697.             } else {

  1698.                 indexnoise = (indexnoise + m_max) & 0x1ff;

  1699.                 for (m = 0; m < m_max; m++) {

  1700.                     Y[1][i][m + kx][0] +=

  1701.                         sbr->s_m[e][m] * phi[0][indexsine];

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

  1703.                         sbr->s_m[e][m] * (phi[1][indexsine] * phi_sign);

  1704.                     phi_sign = -phi_sign;

  1705.                 }

  1706.             }

  1707.             indexsine = (indexsine + 1) & 3;

  1708.         }

  1709.     }

  1710.     ch_data->f_indexnoise = indexnoise;

  1711.     ch_data->f_indexsine  = indexsine;

  1712. }

  1713. 

  1714. void ff_sbr_apply(AACContext *ac, SpectralBandReplication *sbr, int id_aac,

  1715.                   float* L, float* R)

  1716. {

  1717.     int downsampled = ac->m4ac.ext_sample_rate < sbr->sample_rate;

  1718.     int ch;

  1719.     int nch = (id_aac == TYPE_CPE) ? 2 : 1;

  1720. 

  1721.     if (sbr->start) {

  1722.         sbr_dequant(sbr, id_aac);

  1723.     }

  1724.     for (ch = 0; ch < nch; ch++) {

  1725.         /* decode channel */

  1726.         sbr_qmf_analysis(&ac->dsp, &sbr->mdct_ana, ch ? R : L, sbr->data[ch].analysis_filterbank_samples,

  1727.                          (float*)sbr->qmf_filter_scratch,

  1728.                          sbr->data[ch].W);

  1729.         sbr_lf_gen(ac, sbr, sbr->X_low, sbr->data[ch].W);

  1730.         if (sbr->start) {

  1731.             sbr_hf_inverse_filter(sbr->alpha0, sbr->alpha1, sbr->X_low, sbr->k[0]);

  1732.             sbr_chirp(sbr, &sbr->data[ch]);

  1733.             sbr_hf_gen(ac, sbr, sbr->X_high, sbr->X_low, sbr->alpha0, sbr->alpha1,

  1734.                        sbr->data[ch].bw_array, sbr->data[ch].t_env,

  1735.                        sbr->data[ch].bs_num_env);

  1736. 

  1737.             // hf_adj

  1738.             sbr_mapping(ac, sbr, &sbr->data[ch], sbr->data[ch].e_a);

  1739.             sbr_env_estimate(sbr->e_curr, sbr->X_high, sbr, &sbr->data[ch]);

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

  1741.             sbr_hf_assemble(sbr->data[ch].Y, sbr->X_high, sbr, &sbr->data[ch],

  1742.                             sbr->data[ch].e_a);

  1743.         }

  1744. 

  1745.         /* synthesis */

  1746.         sbr_x_gen(sbr, sbr->X[ch], sbr->X_low, sbr->data[ch].Y, ch);

  1747.     }

  1748. 

  1749.     if (ac->m4ac.ps == 1) {

  1750.         if (sbr->ps.start) {

  1751.             ff_ps_apply(ac->avctx, &sbr->ps, sbr->X[0], sbr->X[1], sbr->kx[1] + sbr->m[1]);

  1752.         } else {

  1753.             memcpy(sbr->X[1], sbr->X[0], sizeof(sbr->X[0]));

  1754.         }

  1755.         nch = 2;

  1756.     }

  1757. 

  1758.     sbr_qmf_synthesis(&ac->dsp, &sbr->mdct, L, sbr->X[0], sbr->qmf_filter_scratch,

  1759.                       sbr->data[0].synthesis_filterbank_samples,

  1760.                       &sbr->data[0].synthesis_filterbank_samples_offset,

  1761.                       downsampled);

  1762.     if (nch == 2)

  1763.         sbr_qmf_synthesis(&ac->dsp, &sbr->mdct, R, sbr->X[1], sbr->qmf_filter_scratch,

  1764.                           sbr->data[1].synthesis_filterbank_samples,

  1765.                           &sbr->data[1].synthesis_filterbank_samples_offset,

  1766.                           downsampled);

  1767. }