/*
  * AAC Spectral Band Replication decoding functions
  * Copyright (c) 2008-2009 Robert Swain ( rob opendot cl )
  * Copyright (c) 2009-2010 Alex Converse <alex.converse@gmail.com>
  *

  * Fixed point code
  * Copyright (c) 2013
  *      MIPS Technologies, Inc., California.
  *

  * This file is part of FFmpeg.
  *
  * FFmpeg is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation; either
  * version 2.1 of the License, or (at your option) any later version.
  *
  * FFmpeg is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public
  * License along with FFmpeg; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
 /**
  * @file
  * AAC Spectral Band Replication decoding functions
  * @author Robert Swain ( rob opendot cl )

  * @author Stanislav Ocovaj ( stanislav.ocovaj@imgtec.com )
  * @author Zoran Basaric ( zoran.basaric@imgtec.com )

  */
 

 #include "libavutil/qsort.h"
 

 av_cold void AAC_RENAME(ff_aac_sbr_init)(void)

 {
     static const struct {
         const void *sbr_codes, *sbr_bits;
         const unsigned int table_size, elem_size;
     } sbr_tmp[] = {
         SBR_VLC_ROW(t_huffman_env_1_5dB),
         SBR_VLC_ROW(f_huffman_env_1_5dB),
         SBR_VLC_ROW(t_huffman_env_bal_1_5dB),
         SBR_VLC_ROW(f_huffman_env_bal_1_5dB),
         SBR_VLC_ROW(t_huffman_env_3_0dB),
         SBR_VLC_ROW(f_huffman_env_3_0dB),
         SBR_VLC_ROW(t_huffman_env_bal_3_0dB),
         SBR_VLC_ROW(f_huffman_env_bal_3_0dB),
         SBR_VLC_ROW(t_huffman_noise_3_0dB),
         SBR_VLC_ROW(t_huffman_noise_bal_3_0dB),
     };
 
     // SBR VLC table initialization
     SBR_INIT_VLC_STATIC(0, 1098);
     SBR_INIT_VLC_STATIC(1, 1092);
     SBR_INIT_VLC_STATIC(2, 768);
     SBR_INIT_VLC_STATIC(3, 1026);
     SBR_INIT_VLC_STATIC(4, 1058);
     SBR_INIT_VLC_STATIC(5, 1052);
     SBR_INIT_VLC_STATIC(6, 544);
     SBR_INIT_VLC_STATIC(7, 544);
     SBR_INIT_VLC_STATIC(8, 592);
     SBR_INIT_VLC_STATIC(9, 512);
 
     aacsbr_tableinit();
 

     AAC_RENAME(ff_ps_init)();

 }
 
 /** Places SBR in pure upsampling mode. */
 static void sbr_turnoff(SpectralBandReplication *sbr) {
     sbr->start = 0;

     sbr->ready_for_dequant = 0;

     // Init defults used in pure upsampling mode
     sbr->kx[1] = 32; //Typo in spec, kx' inits to 32
     sbr->m[1] = 0;
     // Reset values for first SBR header
     sbr->data[0].e_a[1] = sbr->data[1].e_a[1] = -1;
     memset(&sbr->spectrum_params, -1, sizeof(SpectrumParameters));
 }
 

 av_cold void AAC_RENAME(ff_aac_sbr_ctx_init)(AACContext *ac, SpectralBandReplication *sbr, int id_aac)

 {
     if(sbr->mdct.mdct_bits)
         return;
     sbr->kx[0] = sbr->kx[1];

     sbr->id_aac = id_aac;

     sbr_turnoff(sbr);
     sbr->data[0].synthesis_filterbank_samples_offset = SBR_SYNTHESIS_BUF_SIZE - (1280 - 128);
     sbr->data[1].synthesis_filterbank_samples_offset = SBR_SYNTHESIS_BUF_SIZE - (1280 - 128);
     /* SBR requires samples to be scaled to +/-32768.0 to work correctly.
      * mdct scale factors are adjusted to scale up from +/-1.0 at analysis
      * and scale back down at synthesis. */

     AAC_RENAME_32(ff_mdct_init)(&sbr->mdct,     7, 1, 1.0 / (64 * 32768.0));
     AAC_RENAME_32(ff_mdct_init)(&sbr->mdct_ana, 7, 1, -2.0 * 32768.0);

     AAC_RENAME(ff_ps_ctx_init)(&sbr->ps);

     AAC_RENAME(ff_sbrdsp_init)(&sbr->dsp);

     aacsbr_func_ptr_init(&sbr->c);
 }
 

 av_cold void AAC_RENAME(ff_aac_sbr_ctx_close)(SpectralBandReplication *sbr)

 {

     AAC_RENAME_32(ff_mdct_end)(&sbr->mdct);
     AAC_RENAME_32(ff_mdct_end)(&sbr->mdct_ana);

 }
 
 static int qsort_comparison_function_int16(const void *a, const void *b)
 {
     return *(const int16_t *)a - *(const int16_t *)b;
 }
 
 static inline int in_table_int16(const int16_t *table, int last_el, int16_t needle)
 {
     int i;
     for (i = 0; i <= last_el; i++)
         if (table[i] == needle)
             return 1;
     return 0;
 }
 
 /// Limiter Frequency Band Table (14496-3 sp04 p198)
 static void sbr_make_f_tablelim(SpectralBandReplication *sbr)
 {
     int k;
     if (sbr->bs_limiter_bands > 0) {

         static const INTFLOAT bands_warped[3] = { Q23(1.32715174233856803909f),   //2^(0.49/1.2)
                                                Q23(1.18509277094158210129f),   //2^(0.49/2)
                                                Q23(1.11987160404675912501f) }; //2^(0.49/3)
         const INTFLOAT lim_bands_per_octave_warped = bands_warped[sbr->bs_limiter_bands - 1];

         int16_t patch_borders[7];
         uint16_t *in = sbr->f_tablelim + 1, *out = sbr->f_tablelim;
 
         patch_borders[0] = sbr->kx[1];
         for (k = 1; k <= sbr->num_patches; k++)
             patch_borders[k] = patch_borders[k-1] + sbr->patch_num_subbands[k-1];
 
         memcpy(sbr->f_tablelim, sbr->f_tablelow,
                (sbr->n[0] + 1) * sizeof(sbr->f_tablelow[0]));
         if (sbr->num_patches > 1)
             memcpy(sbr->f_tablelim + sbr->n[0] + 1, patch_borders + 1,
                    (sbr->num_patches - 1) * sizeof(patch_borders[0]));
 

         AV_QSORT(sbr->f_tablelim, sbr->num_patches + sbr->n[0],
               uint16_t,

               qsort_comparison_function_int16);
 
         sbr->n_lim = sbr->n[0] + sbr->num_patches - 1;
         while (out < sbr->f_tablelim + sbr->n_lim) {

 #if USE_FIXED
             if ((*in << 23) >= *out * lim_bands_per_octave_warped) {
 #else

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

 #endif /* USE_FIXED */

                 *++out = *in++;
             } else if (*in == *out ||
                 !in_table_int16(patch_borders, sbr->num_patches, *in)) {
                 in++;
                 sbr->n_lim--;
             } else if (!in_table_int16(patch_borders, sbr->num_patches, *out)) {
                 *out = *in++;
                 sbr->n_lim--;
             } else {
                 *++out = *in++;
             }
         }
     } else {
         sbr->f_tablelim[0] = sbr->f_tablelow[0];
         sbr->f_tablelim[1] = sbr->f_tablelow[sbr->n[0]];
         sbr->n_lim = 1;
     }
 }
 
 static unsigned int read_sbr_header(SpectralBandReplication *sbr, GetBitContext *gb)
 {
     unsigned int cnt = get_bits_count(gb);
     uint8_t bs_header_extra_1;
     uint8_t bs_header_extra_2;
     int old_bs_limiter_bands = sbr->bs_limiter_bands;
     SpectrumParameters old_spectrum_params;
 
     sbr->start = 1;

     sbr->ready_for_dequant = 0;

 
     // Save last spectrum parameters variables to compare to new ones
     memcpy(&old_spectrum_params, &sbr->spectrum_params, sizeof(SpectrumParameters));
 
     sbr->bs_amp_res_header              = get_bits1(gb);
     sbr->spectrum_params.bs_start_freq  = get_bits(gb, 4);
     sbr->spectrum_params.bs_stop_freq   = get_bits(gb, 4);
     sbr->spectrum_params.bs_xover_band  = get_bits(gb, 3);
                                           skip_bits(gb, 2); // bs_reserved
 
     bs_header_extra_1 = get_bits1(gb);
     bs_header_extra_2 = get_bits1(gb);
 
     if (bs_header_extra_1) {
         sbr->spectrum_params.bs_freq_scale  = get_bits(gb, 2);
         sbr->spectrum_params.bs_alter_scale = get_bits1(gb);
         sbr->spectrum_params.bs_noise_bands = get_bits(gb, 2);
     } else {
         sbr->spectrum_params.bs_freq_scale  = 2;
         sbr->spectrum_params.bs_alter_scale = 1;
         sbr->spectrum_params.bs_noise_bands = 2;
     }
 
     // Check if spectrum parameters changed
     if (memcmp(&old_spectrum_params, &sbr->spectrum_params, sizeof(SpectrumParameters)))
         sbr->reset = 1;
 
     if (bs_header_extra_2) {
         sbr->bs_limiter_bands  = get_bits(gb, 2);
         sbr->bs_limiter_gains  = get_bits(gb, 2);
         sbr->bs_interpol_freq  = get_bits1(gb);
         sbr->bs_smoothing_mode = get_bits1(gb);
     } else {
         sbr->bs_limiter_bands  = 2;
         sbr->bs_limiter_gains  = 2;
         sbr->bs_interpol_freq  = 1;
         sbr->bs_smoothing_mode = 1;
     }
 
     if (sbr->bs_limiter_bands != old_bs_limiter_bands && !sbr->reset)
         sbr_make_f_tablelim(sbr);
 
     return get_bits_count(gb) - cnt;
 }
 
 static int array_min_int16(const int16_t *array, int nel)
 {
     int i, min = array[0];
     for (i = 1; i < nel; i++)
         min = FFMIN(array[i], min);
     return min;
 }
 
 static int check_n_master(AVCodecContext *avctx, int n_master, int bs_xover_band)
 {
     // Requirements (14496-3 sp04 p205)
     if (n_master <= 0) {
         av_log(avctx, AV_LOG_ERROR, "Invalid n_master: %d\n", n_master);
         return -1;
     }
     if (bs_xover_band >= n_master) {
         av_log(avctx, AV_LOG_ERROR,
                "Invalid bitstream, crossover band index beyond array bounds: %d\n",
                bs_xover_band);
         return -1;
     }
     return 0;
 }
 
 /// Master Frequency Band Table (14496-3 sp04 p194)
 static int sbr_make_f_master(AACContext *ac, SpectralBandReplication *sbr,
                              SpectrumParameters *spectrum)
 {
     unsigned int temp, max_qmf_subbands = 0;
     unsigned int start_min, stop_min;
     int k;
     const int8_t *sbr_offset_ptr;
     int16_t stop_dk[13];
 
     switch (sbr->sample_rate) {
     case 16000:
         sbr_offset_ptr = sbr_offset[0];
         break;
     case 22050:
         sbr_offset_ptr = sbr_offset[1];
         break;
     case 24000:
         sbr_offset_ptr = sbr_offset[2];
         break;
     case 32000:
         sbr_offset_ptr = sbr_offset[3];
         break;
     case 44100: case 48000: case 64000:
         sbr_offset_ptr = sbr_offset[4];
         break;
     case 88200: case 96000: case 128000: case 176400: case 192000:
         sbr_offset_ptr = sbr_offset[5];
         break;
     default:
         av_log(ac->avctx, AV_LOG_ERROR,
                "Unsupported sample rate for SBR: %d\n", sbr->sample_rate);
         return -1;
     }
 

     if (sbr->sample_rate < 32000) {
         temp = 3000;
     } else if (sbr->sample_rate < 64000) {
         temp = 4000;
     } else
         temp = 5000;
 

     start_min = ((temp << 7) + (sbr->sample_rate >> 1)) / sbr->sample_rate;
     stop_min  = ((temp << 8) + (sbr->sample_rate >> 1)) / sbr->sample_rate;
 
     sbr->k[0] = start_min + sbr_offset_ptr[spectrum->bs_start_freq];
 
     if (spectrum->bs_stop_freq < 14) {
         sbr->k[2] = stop_min;
         make_bands(stop_dk, stop_min, 64, 13);

         AV_QSORT(stop_dk, 13, int16_t, qsort_comparison_function_int16);

         for (k = 0; k < spectrum->bs_stop_freq; k++)
             sbr->k[2] += stop_dk[k];
     } else if (spectrum->bs_stop_freq == 14) {
         sbr->k[2] = 2*sbr->k[0];
     } else if (spectrum->bs_stop_freq == 15) {
         sbr->k[2] = 3*sbr->k[0];
     } else {
         av_log(ac->avctx, AV_LOG_ERROR,
                "Invalid bs_stop_freq: %d\n", spectrum->bs_stop_freq);
         return -1;
     }
     sbr->k[2] = FFMIN(64, sbr->k[2]);
 
     // Requirements (14496-3 sp04 p205)
     if (sbr->sample_rate <= 32000) {
         max_qmf_subbands = 48;
     } else if (sbr->sample_rate == 44100) {
         max_qmf_subbands = 35;
     } else if (sbr->sample_rate >= 48000)
         max_qmf_subbands = 32;
     else
         av_assert0(0);
 
     if (sbr->k[2] - sbr->k[0] > max_qmf_subbands) {
         av_log(ac->avctx, AV_LOG_ERROR,
                "Invalid bitstream, too many QMF subbands: %d\n", sbr->k[2] - sbr->k[0]);
         return -1;
     }
 
     if (!spectrum->bs_freq_scale) {
         int dk, k2diff;
 
         dk = spectrum->bs_alter_scale + 1;
         sbr->n_master = ((sbr->k[2] - sbr->k[0] + (dk&2)) >> dk) << 1;
         if (check_n_master(ac->avctx, sbr->n_master, sbr->spectrum_params.bs_xover_band))
             return -1;
 
         for (k = 1; k <= sbr->n_master; k++)
             sbr->f_master[k] = dk;
 
         k2diff = sbr->k[2] - sbr->k[0] - sbr->n_master * dk;
         if (k2diff < 0) {
             sbr->f_master[1]--;
             sbr->f_master[2]-= (k2diff < -1);
         } else if (k2diff) {
             sbr->f_master[sbr->n_master]++;
         }
 
         sbr->f_master[0] = sbr->k[0];
         for (k = 1; k <= sbr->n_master; k++)
             sbr->f_master[k] += sbr->f_master[k - 1];
 
     } else {
         int half_bands = 7 - spectrum->bs_freq_scale;      // bs_freq_scale  = {1,2,3}
         int two_regions, num_bands_0;
         int vdk0_max, vdk1_min;
         int16_t vk0[49];

 #if USE_FIXED
         int tmp, nz = 0;
 #endif /* USE_FIXED */

 
         if (49 * sbr->k[2] > 110 * sbr->k[0]) {
             two_regions = 1;
             sbr->k[1] = 2 * sbr->k[0];
         } else {
             two_regions = 0;
             sbr->k[1] = sbr->k[2];
         }
 

 #if USE_FIXED
         tmp = (sbr->k[1] << 23) / sbr->k[0];
         while (tmp < 0x40000000) {
           tmp <<= 1;
           nz++;
         }
         tmp = fixed_log(tmp - 0x80000000);
         tmp = (int)(((int64_t)tmp * CONST_RECIP_LN2 + 0x20000000) >> 30);
         tmp = (((tmp + 0x80) >> 8) + ((8 - nz) << 23)) * half_bands;
         num_bands_0 = ((tmp + 0x400000) >> 23) * 2;
 #else

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

 #endif /* USE_FIXED */

 
         if (num_bands_0 <= 0) { // Requirements (14496-3 sp04 p205)
             av_log(ac->avctx, AV_LOG_ERROR, "Invalid num_bands_0: %d\n", num_bands_0);
             return -1;
         }
 
         vk0[0] = 0;
 
         make_bands(vk0+1, sbr->k[0], sbr->k[1], num_bands_0);
 

         AV_QSORT(vk0 + 1, num_bands_0, int16_t, qsort_comparison_function_int16);

         vdk0_max = vk0[num_bands_0];
 
         vk0[0] = sbr->k[0];
         for (k = 1; k <= num_bands_0; k++) {
             if (vk0[k] <= 0) { // Requirements (14496-3 sp04 p205)
                 av_log(ac->avctx, AV_LOG_ERROR, "Invalid vDk0[%d]: %d\n", k, vk0[k]);
                 return -1;
             }
             vk0[k] += vk0[k-1];
         }
 
         if (two_regions) {
             int16_t vk1[49];

 #if USE_FIXED
             int num_bands_1;
 
             tmp = (sbr->k[2] << 23) / sbr->k[1];
             nz = 0;
             while (tmp < 0x40000000) {
               tmp <<= 1;
               nz++;
             }
             tmp = fixed_log(tmp - 0x80000000);
             tmp = (int)(((int64_t)tmp * CONST_RECIP_LN2 + 0x20000000) >> 30);
             tmp = (((tmp + 0x80) >> 8) + ((8 - nz) << 23)) * half_bands;
             if (spectrum->bs_alter_scale)
                 tmp = (int)(((int64_t)tmp * CONST_076923 + 0x40000000) >> 31);
             num_bands_1 = ((tmp + 0x400000) >> 23) * 2;
 #else

             float invwarp = spectrum->bs_alter_scale ? 0.76923076923076923077f
                                                      : 1.0f; // bs_alter_scale = {0,1}
             int num_bands_1 = lrintf(half_bands * invwarp *
                                      log2f(sbr->k[2] / (float)sbr->k[1])) * 2;

 #endif /* USE_FIXED */

             make_bands(vk1+1, sbr->k[1], sbr->k[2], num_bands_1);
 
             vdk1_min = array_min_int16(vk1 + 1, num_bands_1);
 
             if (vdk1_min < vdk0_max) {
                 int change;

                 AV_QSORT(vk1 + 1, num_bands_1, int16_t, qsort_comparison_function_int16);

                 change = FFMIN(vdk0_max - vk1[1], (vk1[num_bands_1] - vk1[1]) >> 1);
                 vk1[1]           += change;
                 vk1[num_bands_1] -= change;
             }
 

             AV_QSORT(vk1 + 1, num_bands_1, int16_t, qsort_comparison_function_int16);

 
             vk1[0] = sbr->k[1];
             for (k = 1; k <= num_bands_1; k++) {
                 if (vk1[k] <= 0) { // Requirements (14496-3 sp04 p205)
                     av_log(ac->avctx, AV_LOG_ERROR, "Invalid vDk1[%d]: %d\n", k, vk1[k]);
                     return -1;
                 }
                 vk1[k] += vk1[k-1];
             }
 
             sbr->n_master = num_bands_0 + num_bands_1;
             if (check_n_master(ac->avctx, sbr->n_master, sbr->spectrum_params.bs_xover_band))
                 return -1;
             memcpy(&sbr->f_master[0],               vk0,
                    (num_bands_0 + 1) * sizeof(sbr->f_master[0]));
             memcpy(&sbr->f_master[num_bands_0 + 1], vk1 + 1,
                     num_bands_1      * sizeof(sbr->f_master[0]));
 
         } else {
             sbr->n_master = num_bands_0;
             if (check_n_master(ac->avctx, sbr->n_master, sbr->spectrum_params.bs_xover_band))
                 return -1;
             memcpy(sbr->f_master, vk0, (num_bands_0 + 1) * sizeof(sbr->f_master[0]));
         }
     }
 
     return 0;
 }
 
 /// High Frequency Generation - Patch Construction (14496-3 sp04 p216 fig. 4.46)
 static int sbr_hf_calc_npatches(AACContext *ac, SpectralBandReplication *sbr)
 {
     int i, k, last_k = -1, last_msb = -1, sb = 0;
     int msb = sbr->k[0];
     int usb = sbr->kx[1];
     int goal_sb = ((1000 << 11) + (sbr->sample_rate >> 1)) / sbr->sample_rate;
 
     sbr->num_patches = 0;
 
     if (goal_sb < sbr->kx[1] + sbr->m[1]) {
         for (k = 0; sbr->f_master[k] < goal_sb; k++) ;
     } else
         k = sbr->n_master;
 
     do {
         int odd = 0;
         if (k == last_k && msb == last_msb) {
             av_log(ac->avctx, AV_LOG_ERROR, "patch construction failed\n");
             return AVERROR_INVALIDDATA;
         }
         last_k = k;
         last_msb = msb;
         for (i = k; i == k || sb > (sbr->k[0] - 1 + msb - odd); i--) {
             sb = sbr->f_master[i];
             odd = (sb + sbr->k[0]) & 1;
         }
 
         // Requirements (14496-3 sp04 p205) sets the maximum number of patches to 5.
         // After this check the final number of patches can still be six which is
         // illegal however the Coding Technologies decoder check stream has a final
         // count of 6 patches
         if (sbr->num_patches > 5) {
             av_log(ac->avctx, AV_LOG_ERROR, "Too many patches: %d\n", sbr->num_patches);
             return -1;
         }
 
         sbr->patch_num_subbands[sbr->num_patches]  = FFMAX(sb - usb, 0);
         sbr->patch_start_subband[sbr->num_patches] = sbr->k[0] - odd - sbr->patch_num_subbands[sbr->num_patches];
 
         if (sbr->patch_num_subbands[sbr->num_patches] > 0) {
             usb = sb;
             msb = sb;
             sbr->num_patches++;
         } else
             msb = sbr->kx[1];
 
         if (sbr->f_master[k] - sb < 3)
             k = sbr->n_master;
     } while (sb != sbr->kx[1] + sbr->m[1]);
 
     if (sbr->num_patches > 1 &&
         sbr->patch_num_subbands[sbr->num_patches - 1] < 3)
         sbr->num_patches--;
 
     return 0;
 }
 
 /// Derived Frequency Band Tables (14496-3 sp04 p197)
 static int sbr_make_f_derived(AACContext *ac, SpectralBandReplication *sbr)
 {
     int k, temp;

 #if USE_FIXED
     int nz = 0;
 #endif /* USE_FIXED */

 
     sbr->n[1] = sbr->n_master - sbr->spectrum_params.bs_xover_band;
     sbr->n[0] = (sbr->n[1] + 1) >> 1;
 
     memcpy(sbr->f_tablehigh, &sbr->f_master[sbr->spectrum_params.bs_xover_band],
            (sbr->n[1] + 1) * sizeof(sbr->f_master[0]));
     sbr->m[1] = sbr->f_tablehigh[sbr->n[1]] - sbr->f_tablehigh[0];
     sbr->kx[1] = sbr->f_tablehigh[0];
 
     // Requirements (14496-3 sp04 p205)
     if (sbr->kx[1] + sbr->m[1] > 64) {
         av_log(ac->avctx, AV_LOG_ERROR,
                "Stop frequency border too high: %d\n", sbr->kx[1] + sbr->m[1]);
         return -1;
     }
     if (sbr->kx[1] > 32) {
         av_log(ac->avctx, AV_LOG_ERROR, "Start frequency border too high: %d\n", sbr->kx[1]);
         return -1;
     }
 
     sbr->f_tablelow[0] = sbr->f_tablehigh[0];
     temp = sbr->n[1] & 1;
     for (k = 1; k <= sbr->n[0]; k++)
         sbr->f_tablelow[k] = sbr->f_tablehigh[2 * k - temp];

 #if USE_FIXED
     temp = (sbr->k[2] << 23) / sbr->kx[1];
     while (temp < 0x40000000) {
         temp <<= 1;
         nz++;
     }
     temp = fixed_log(temp - 0x80000000);
     temp = (int)(((int64_t)temp * CONST_RECIP_LN2 + 0x20000000) >> 30);
     temp = (((temp + 0x80) >> 8) + ((8 - nz) << 23)) * sbr->spectrum_params.bs_noise_bands;

     sbr->n_q = (temp + 0x400000) >> 23;
     if (sbr->n_q < 1)
         sbr->n_q = 1;
 #else

     sbr->n_q = FFMAX(1, lrintf(sbr->spectrum_params.bs_noise_bands *
                                log2f(sbr->k[2] / (float)sbr->kx[1]))); // 0 <= bs_noise_bands <= 3

 #endif /* USE_FIXED */
 

     if (sbr->n_q > 5) {
         av_log(ac->avctx, AV_LOG_ERROR, "Too many noise floor scale factors: %d\n", sbr->n_q);
         return -1;
     }
 
     sbr->f_tablenoise[0] = sbr->f_tablelow[0];
     temp = 0;
     for (k = 1; k <= sbr->n_q; k++) {
         temp += (sbr->n[0] - temp) / (sbr->n_q + 1 - k);
         sbr->f_tablenoise[k] = sbr->f_tablelow[temp];
     }
 
     if (sbr_hf_calc_npatches(ac, sbr) < 0)
         return -1;
 
     sbr_make_f_tablelim(sbr);
 
     sbr->data[0].f_indexnoise = 0;
     sbr->data[1].f_indexnoise = 0;
 
     return 0;
 }
 
 static av_always_inline void get_bits1_vector(GetBitContext *gb, uint8_t *vec,
                                               int elements)
 {
     int i;
     for (i = 0; i < elements; i++) {
         vec[i] = get_bits1(gb);
     }
 }
 
 /** ceil(log2(index+1)) */
 static const int8_t ceil_log2[] = {
     0, 1, 2, 2, 3, 3,
 };
 
 static int read_sbr_grid(AACContext *ac, SpectralBandReplication *sbr,
                          GetBitContext *gb, SBRData *ch_data)
 {
     int i;
     int bs_pointer = 0;
     // frameLengthFlag ? 15 : 16; 960 sample length frames unsupported; this value is numTimeSlots
     int abs_bord_trail = 16;
     int num_rel_lead, num_rel_trail;
     unsigned bs_num_env_old = ch_data->bs_num_env;

     int bs_frame_class, bs_num_env;

 
     ch_data->bs_freq_res[0] = ch_data->bs_freq_res[ch_data->bs_num_env];
     ch_data->bs_amp_res = sbr->bs_amp_res_header;
     ch_data->t_env_num_env_old = ch_data->t_env[bs_num_env_old];
 

     switch (bs_frame_class = get_bits(gb, 2)) {

     case FIXFIX:

         bs_num_env = 1 << get_bits(gb, 2);
         if (bs_num_env > 4) {

             av_log(ac->avctx, AV_LOG_ERROR,
                    "Invalid bitstream, too many SBR envelopes in FIXFIX type SBR frame: %d\n",

                    bs_num_env);

             return -1;
         }

         ch_data->bs_num_env = bs_num_env;
         num_rel_lead                        = ch_data->bs_num_env - 1;
         if (ch_data->bs_num_env == 1)
             ch_data->bs_amp_res = 0;
 

 
         ch_data->t_env[0]                   = 0;
         ch_data->t_env[ch_data->bs_num_env] = abs_bord_trail;
 
         abs_bord_trail = (abs_bord_trail + (ch_data->bs_num_env >> 1)) /
                    ch_data->bs_num_env;
         for (i = 0; i < num_rel_lead; i++)
             ch_data->t_env[i + 1] = ch_data->t_env[i] + abs_bord_trail;
 
         ch_data->bs_freq_res[1] = get_bits1(gb);
         for (i = 1; i < ch_data->bs_num_env; i++)
             ch_data->bs_freq_res[i + 1] = ch_data->bs_freq_res[1];
         break;
     case FIXVAR:
         abs_bord_trail                     += get_bits(gb, 2);
         num_rel_trail                       = get_bits(gb, 2);
         ch_data->bs_num_env                 = num_rel_trail + 1;
         ch_data->t_env[0]                   = 0;
         ch_data->t_env[ch_data->bs_num_env] = abs_bord_trail;
 
         for (i = 0; i < num_rel_trail; i++)
             ch_data->t_env[ch_data->bs_num_env - 1 - i] =
                 ch_data->t_env[ch_data->bs_num_env - i] - 2 * get_bits(gb, 2) - 2;
 
         bs_pointer = get_bits(gb, ceil_log2[ch_data->bs_num_env]);
 
         for (i = 0; i < ch_data->bs_num_env; i++)
             ch_data->bs_freq_res[ch_data->bs_num_env - i] = get_bits1(gb);
         break;
     case VARFIX:
         ch_data->t_env[0]                   = get_bits(gb, 2);
         num_rel_lead                        = get_bits(gb, 2);
         ch_data->bs_num_env                 = num_rel_lead + 1;
         ch_data->t_env[ch_data->bs_num_env] = abs_bord_trail;
 
         for (i = 0; i < num_rel_lead; i++)
             ch_data->t_env[i + 1] = ch_data->t_env[i] + 2 * get_bits(gb, 2) + 2;
 
         bs_pointer = get_bits(gb, ceil_log2[ch_data->bs_num_env]);
 
         get_bits1_vector(gb, ch_data->bs_freq_res + 1, ch_data->bs_num_env);
         break;
     case VARVAR:
         ch_data->t_env[0]                   = get_bits(gb, 2);
         abs_bord_trail                     += get_bits(gb, 2);
         num_rel_lead                        = get_bits(gb, 2);
         num_rel_trail                       = get_bits(gb, 2);

         bs_num_env                          = num_rel_lead + num_rel_trail + 1;

         if (bs_num_env > 5) {

             av_log(ac->avctx, AV_LOG_ERROR,
                    "Invalid bitstream, too many SBR envelopes in VARVAR type SBR frame: %d\n",

                    bs_num_env);

             return -1;
         }

         ch_data->bs_num_env = bs_num_env;

 
         ch_data->t_env[ch_data->bs_num_env] = abs_bord_trail;
 
         for (i = 0; i < num_rel_lead; i++)
             ch_data->t_env[i + 1] = ch_data->t_env[i] + 2 * get_bits(gb, 2) + 2;
         for (i = 0; i < num_rel_trail; i++)
             ch_data->t_env[ch_data->bs_num_env - 1 - i] =
                 ch_data->t_env[ch_data->bs_num_env - i] - 2 * get_bits(gb, 2) - 2;
 
         bs_pointer = get_bits(gb, ceil_log2[ch_data->bs_num_env]);
 
         get_bits1_vector(gb, ch_data->bs_freq_res + 1, ch_data->bs_num_env);
         break;
     }

     ch_data->bs_frame_class = bs_frame_class;

 
     av_assert0(bs_pointer >= 0);
     if (bs_pointer > ch_data->bs_num_env + 1) {
         av_log(ac->avctx, AV_LOG_ERROR,
                "Invalid bitstream, bs_pointer points to a middle noise border outside the time borders table: %d\n",
                bs_pointer);
         return -1;
     }
 
     for (i = 1; i <= ch_data->bs_num_env; i++) {

         if (ch_data->t_env[i-1] >= ch_data->t_env[i]) {
             av_log(ac->avctx, AV_LOG_ERROR, "Not strictly monotone time borders\n");

             return -1;
         }
     }
 
     ch_data->bs_num_noise = (ch_data->bs_num_env > 1) + 1;
 
     ch_data->t_q[0]                     = ch_data->t_env[0];
     ch_data->t_q[ch_data->bs_num_noise] = ch_data->t_env[ch_data->bs_num_env];
     if (ch_data->bs_num_noise > 1) {
         int idx;
         if (ch_data->bs_frame_class == FIXFIX) {
             idx = ch_data->bs_num_env >> 1;
         } else if (ch_data->bs_frame_class & 1) { // FIXVAR or VARVAR
             idx = ch_data->bs_num_env - FFMAX(bs_pointer - 1, 1);
         } else { // VARFIX
             if (!bs_pointer)
                 idx = 1;
             else if (bs_pointer == 1)
                 idx = ch_data->bs_num_env - 1;
             else // bs_pointer > 1
                 idx = bs_pointer - 1;
         }
         ch_data->t_q[1] = ch_data->t_env[idx];
     }
 
     ch_data->e_a[0] = -(ch_data->e_a[1] != bs_num_env_old); // l_APrev
     ch_data->e_a[1] = -1;
     if ((ch_data->bs_frame_class & 1) && bs_pointer) { // FIXVAR or VARVAR and bs_pointer != 0
         ch_data->e_a[1] = ch_data->bs_num_env + 1 - bs_pointer;
     } else if ((ch_data->bs_frame_class == 2) && (bs_pointer > 1)) // VARFIX and bs_pointer > 1
         ch_data->e_a[1] = bs_pointer - 1;
 
     return 0;
 }
 
 static void copy_sbr_grid(SBRData *dst, const SBRData *src) {
     //These variables are saved from the previous frame rather than copied
     dst->bs_freq_res[0]    = dst->bs_freq_res[dst->bs_num_env];
     dst->t_env_num_env_old = dst->t_env[dst->bs_num_env];
     dst->e_a[0]            = -(dst->e_a[1] != dst->bs_num_env);
 
     //These variables are read from the bitstream and therefore copied
     memcpy(dst->bs_freq_res+1, src->bs_freq_res+1, sizeof(dst->bs_freq_res)-sizeof(*dst->bs_freq_res));
     memcpy(dst->t_env,         src->t_env,         sizeof(dst->t_env));
     memcpy(dst->t_q,           src->t_q,           sizeof(dst->t_q));
     dst->bs_num_env        = src->bs_num_env;
     dst->bs_amp_res        = src->bs_amp_res;
     dst->bs_num_noise      = src->bs_num_noise;
     dst->bs_frame_class    = src->bs_frame_class;
     dst->e_a[1]            = src->e_a[1];
 }
 
 /// Read how the envelope and noise floor data is delta coded
 static void read_sbr_dtdf(SpectralBandReplication *sbr, GetBitContext *gb,
                           SBRData *ch_data)
 {
     get_bits1_vector(gb, ch_data->bs_df_env,   ch_data->bs_num_env);
     get_bits1_vector(gb, ch_data->bs_df_noise, ch_data->bs_num_noise);
 }
 
 /// Read inverse filtering data
 static void read_sbr_invf(SpectralBandReplication *sbr, GetBitContext *gb,
                           SBRData *ch_data)
 {
     int i;
 
     memcpy(ch_data->bs_invf_mode[1], ch_data->bs_invf_mode[0], 5 * sizeof(uint8_t));
     for (i = 0; i < sbr->n_q; i++)
         ch_data->bs_invf_mode[0][i] = get_bits(gb, 2);
 }
 

 static int read_sbr_envelope(AACContext *ac, SpectralBandReplication *sbr, GetBitContext *gb,

                               SBRData *ch_data, int ch)
 {
     int bits;
     int i, j, k;
     VLC_TYPE (*t_huff)[2], (*f_huff)[2];
     int t_lav, f_lav;
     const int delta = (ch == 1 && sbr->bs_coupling == 1) + 1;
     const int odd = sbr->n[1] & 1;
 
     if (sbr->bs_coupling && ch) {
         if (ch_data->bs_amp_res) {
             bits   = 5;
             t_huff = vlc_sbr[T_HUFFMAN_ENV_BAL_3_0DB].table;
             t_lav  = vlc_sbr_lav[T_HUFFMAN_ENV_BAL_3_0DB];
             f_huff = vlc_sbr[F_HUFFMAN_ENV_BAL_3_0DB].table;
             f_lav  = vlc_sbr_lav[F_HUFFMAN_ENV_BAL_3_0DB];
         } else {
             bits   = 6;
             t_huff = vlc_sbr[T_HUFFMAN_ENV_BAL_1_5DB].table;
             t_lav  = vlc_sbr_lav[T_HUFFMAN_ENV_BAL_1_5DB];
             f_huff = vlc_sbr[F_HUFFMAN_ENV_BAL_1_5DB].table;
             f_lav  = vlc_sbr_lav[F_HUFFMAN_ENV_BAL_1_5DB];
         }
     } else {
         if (ch_data->bs_amp_res) {
             bits   = 6;
             t_huff = vlc_sbr[T_HUFFMAN_ENV_3_0DB].table;
             t_lav  = vlc_sbr_lav[T_HUFFMAN_ENV_3_0DB];
             f_huff = vlc_sbr[F_HUFFMAN_ENV_3_0DB].table;
             f_lav  = vlc_sbr_lav[F_HUFFMAN_ENV_3_0DB];
         } else {
             bits   = 7;
             t_huff = vlc_sbr[T_HUFFMAN_ENV_1_5DB].table;
             t_lav  = vlc_sbr_lav[T_HUFFMAN_ENV_1_5DB];
             f_huff = vlc_sbr[F_HUFFMAN_ENV_1_5DB].table;
             f_lav  = vlc_sbr_lav[F_HUFFMAN_ENV_1_5DB];
         }
     }
 

     for (i = 0; i < ch_data->bs_num_env; i++) {
         if (ch_data->bs_df_env[i]) {
             // bs_freq_res[0] == bs_freq_res[bs_num_env] from prev frame
             if (ch_data->bs_freq_res[i + 1] == ch_data->bs_freq_res[i]) {

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

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

                     if (ch_data->env_facs_q[i + 1][j] > 127U) {
                         av_log(ac->avctx, AV_LOG_ERROR, "env_facs_q %d is invalid\n", ch_data->env_facs_q[i + 1][j]);
                         return AVERROR_INVALIDDATA;
                     }
                 }

             } else if (ch_data->bs_freq_res[i + 1]) {
                 for (j = 0; j < sbr->n[ch_data->bs_freq_res[i + 1]]; j++) {
                     k = (j + odd) >> 1; // find k such that f_tablelow[k] <= f_tablehigh[j] < f_tablelow[k + 1]

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

                     if (ch_data->env_facs_q[i + 1][j] > 127U) {
                         av_log(ac->avctx, AV_LOG_ERROR, "env_facs_q %d is invalid\n", ch_data->env_facs_q[i + 1][j]);
                         return AVERROR_INVALIDDATA;
                     }

                 }
             } else {
                 for (j = 0; j < sbr->n[ch_data->bs_freq_res[i + 1]]; j++) {
                     k = j ? 2*j - odd : 0; // find k such that f_tablehigh[k] == f_tablelow[j]

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

                     if (ch_data->env_facs_q[i + 1][j] > 127U) {
                         av_log(ac->avctx, AV_LOG_ERROR, "env_facs_q %d is invalid\n", ch_data->env_facs_q[i + 1][j]);
                         return AVERROR_INVALIDDATA;
                     }

                 }
             }
         } else {

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

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

                 ch_data->env_facs_q[i + 1][j] = ch_data->env_facs_q[i + 1][j - 1] + delta * (get_vlc2(gb, f_huff, 9, 3) - f_lav);

                 if (ch_data->env_facs_q[i + 1][j] > 127U) {
                     av_log(ac->avctx, AV_LOG_ERROR, "env_facs_q %d is invalid\n", ch_data->env_facs_q[i + 1][j]);
                     return AVERROR_INVALIDDATA;
                 }
             }

         }
     }

     //assign 0th elements of env_facs_q from last elements
     memcpy(ch_data->env_facs_q[0], ch_data->env_facs_q[ch_data->bs_num_env],
            sizeof(ch_data->env_facs_q[0]));

 
     return 0;

 }
 

 static int read_sbr_noise(AACContext *ac, SpectralBandReplication *sbr, GetBitContext *gb,

                            SBRData *ch_data, int ch)
 {
     int i, j;
     VLC_TYPE (*t_huff)[2], (*f_huff)[2];
     int t_lav, f_lav;
     int delta = (ch == 1 && sbr->bs_coupling == 1) + 1;
 
     if (sbr->bs_coupling && ch) {
         t_huff = vlc_sbr[T_HUFFMAN_NOISE_BAL_3_0DB].table;
         t_lav  = vlc_sbr_lav[T_HUFFMAN_NOISE_BAL_3_0DB];
         f_huff = vlc_sbr[F_HUFFMAN_ENV_BAL_3_0DB].table;
         f_lav  = vlc_sbr_lav[F_HUFFMAN_ENV_BAL_3_0DB];
     } else {
         t_huff = vlc_sbr[T_HUFFMAN_NOISE_3_0DB].table;
         t_lav  = vlc_sbr_lav[T_HUFFMAN_NOISE_3_0DB];
         f_huff = vlc_sbr[F_HUFFMAN_ENV_3_0DB].table;
         f_lav  = vlc_sbr_lav[F_HUFFMAN_ENV_3_0DB];
     }
 
     for (i = 0; i < ch_data->bs_num_noise; i++) {
         if (ch_data->bs_df_noise[i]) {

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

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

                 if (ch_data->noise_facs_q[i + 1][j] > 30U) {
                     av_log(ac->avctx, AV_LOG_ERROR, "noise_facs_q %d is invalid\n", ch_data->noise_facs_q[i + 1][j]);
                     return AVERROR_INVALIDDATA;
                 }
             }

         } else {

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

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

                 ch_data->noise_facs_q[i + 1][j] = ch_data->noise_facs_q[i + 1][j - 1] + delta * (get_vlc2(gb, f_huff, 9, 3) - f_lav);

                 if (ch_data->noise_facs_q[i + 1][j] > 30U) {
                     av_log(ac->avctx, AV_LOG_ERROR, "noise_facs_q %d is invalid\n", ch_data->noise_facs_q[i + 1][j]);
                     return AVERROR_INVALIDDATA;
                 }
             }

         }
     }
 

     //assign 0th elements of noise_facs_q from last elements
     memcpy(ch_data->noise_facs_q[0], ch_data->noise_facs_q[ch_data->bs_num_noise],
            sizeof(ch_data->noise_facs_q[0]));

     return 0;

 }
 
 static void read_sbr_extension(AACContext *ac, SpectralBandReplication *sbr,
                                GetBitContext *gb,
                                int bs_extension_id, int *num_bits_left)
 {
     switch (bs_extension_id) {
     case EXTENSION_ID_PS:
         if (!ac->oc[1].m4ac.ps) {
             av_log(ac->avctx, AV_LOG_ERROR, "Parametric Stereo signaled to be not-present but was found in the bitstream.\n");
             skip_bits_long(gb, *num_bits_left); // bs_fill_bits
             *num_bits_left = 0;
         } else {

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

             ac->avctx->profile = FF_PROFILE_AAC_HE_V2;
         }
         break;
     default:
         // some files contain 0-padding
         if (bs_extension_id || *num_bits_left > 16 || show_bits(gb, *num_bits_left))
             avpriv_request_sample(ac->avctx, "Reserved SBR extensions");
         skip_bits_long(gb, *num_bits_left); // bs_fill_bits
         *num_bits_left = 0;
         break;
     }
 }
 
 static int read_sbr_single_channel_element(AACContext *ac,
                                             SpectralBandReplication *sbr,
                                             GetBitContext *gb)
 {

     int ret;
 

     if (get_bits1(gb)) // bs_data_extra
         skip_bits(gb, 4); // bs_reserved
 
     if (read_sbr_grid(ac, sbr, gb, &sbr->data[0]))
         return -1;
     read_sbr_dtdf(sbr, gb, &sbr->data[0]);
     read_sbr_invf(sbr, gb, &sbr->data[0]);

     if((ret = read_sbr_envelope(ac, sbr, gb, &sbr->data[0], 0)) < 0)
         return ret;

     if((ret = read_sbr_noise(ac, sbr, gb, &sbr->data[0], 0)) < 0)
         return ret;

 
     if ((sbr->data[0].bs_add_harmonic_flag = get_bits1(gb)))
         get_bits1_vector(gb, sbr->data[0].bs_add_harmonic, sbr->n[1]);
 
     return 0;
 }
 
 static int read_sbr_channel_pair_element(AACContext *ac,
                                           SpectralBandReplication *sbr,
                                           GetBitContext *gb)
 {

     int ret;
 

     if (get_bits1(gb))    // bs_data_extra
         skip_bits(gb, 8); // bs_reserved
 
     if ((sbr->bs_coupling = get_bits1(gb))) {
         if (read_sbr_grid(ac, sbr, gb, &sbr->data[0]))
             return -1;
         copy_sbr_grid(&sbr->data[1], &sbr->data[0]);
         read_sbr_dtdf(sbr, gb, &sbr->data[0]);
         read_sbr_dtdf(sbr, gb, &sbr->data[1]);
         read_sbr_invf(sbr, gb, &sbr->data[0]);
         memcpy(sbr->data[1].bs_invf_mode[1], sbr->data[1].bs_invf_mode[0], sizeof(sbr->data[1].bs_invf_mode[0]));
         memcpy(sbr->data[1].bs_invf_mode[0], sbr->data[0].bs_invf_mode[0], sizeof(sbr->data[1].bs_invf_mode[0]));

         if((ret = read_sbr_envelope(ac, sbr, gb, &sbr->data[0], 0)) < 0)
             return ret;

         if((ret = read_sbr_noise(ac, sbr, gb, &sbr->data[0], 0)) < 0)
             return ret;

         if((ret = read_sbr_envelope(ac, sbr, gb, &sbr->data[1], 1)) < 0)
             return ret;

         if((ret = read_sbr_noise(ac, sbr, gb, &sbr->data[1], 1)) < 0)
             return ret;

     } else {
         if (read_sbr_grid(ac, sbr, gb, &sbr->data[0]) ||
             read_sbr_grid(ac, sbr, gb, &sbr->data[1]))
             return -1;
         read_sbr_dtdf(sbr, gb, &sbr->data[0]);
         read_sbr_dtdf(sbr, gb, &sbr->data[1]);
         read_sbr_invf(sbr, gb, &sbr->data[0]);
         read_sbr_invf(sbr, gb, &sbr->data[1]);

         if((ret = read_sbr_envelope(ac, sbr, gb, &sbr->data[0], 0)) < 0)
             return ret;
         if((ret = read_sbr_envelope(ac, sbr, gb, &sbr->data[1], 1)) < 0)
             return ret;

         if((ret = read_sbr_noise(ac, sbr, gb, &sbr->data[0], 0)) < 0)
             return ret;
         if((ret = read_sbr_noise(ac, sbr, gb, &sbr->data[1], 1)) < 0)
             return ret;

     }
 
     if ((sbr->data[0].bs_add_harmonic_flag = get_bits1(gb)))
         get_bits1_vector(gb, sbr->data[0].bs_add_harmonic, sbr->n[1]);
     if ((sbr->data[1].bs_add_harmonic_flag = get_bits1(gb)))
         get_bits1_vector(gb, sbr->data[1].bs_add_harmonic, sbr->n[1]);
 
     return 0;
 }
 
 static unsigned int read_sbr_data(AACContext *ac, SpectralBandReplication *sbr,
                                   GetBitContext *gb, int id_aac)
 {
     unsigned int cnt = get_bits_count(gb);
 
     sbr->id_aac = id_aac;

     sbr->ready_for_dequant = 1;

 
     if (id_aac == TYPE_SCE || id_aac == TYPE_CCE) {
         if (read_sbr_single_channel_element(ac, sbr, gb)) {
             sbr_turnoff(sbr);
             return get_bits_count(gb) - cnt;
         }
     } else if (id_aac == TYPE_CPE) {
         if (read_sbr_channel_pair_element(ac, sbr, gb)) {
             sbr_turnoff(sbr);
             return get_bits_count(gb) - cnt;
         }
     } else {
         av_log(ac->avctx, AV_LOG_ERROR,
             "Invalid bitstream - cannot apply SBR to element type %d\n", id_aac);
         sbr_turnoff(sbr);
         return get_bits_count(gb) - cnt;
     }
     if (get_bits1(gb)) { // bs_extended_data
         int num_bits_left = get_bits(gb, 4); // bs_extension_size
         if (num_bits_left == 15)
             num_bits_left += get_bits(gb, 8); // bs_esc_count
 
         num_bits_left <<= 3;
         while (num_bits_left > 7) {
             num_bits_left -= 2;
             read_sbr_extension(ac, sbr, gb, get_bits(gb, 2), &num_bits_left); // bs_extension_id
         }
         if (num_bits_left < 0) {
             av_log(ac->avctx, AV_LOG_ERROR, "SBR Extension over read.\n");
         }
         if (num_bits_left > 0)
             skip_bits(gb, num_bits_left);
     }
 
     return get_bits_count(gb) - cnt;
 }
 
 static void sbr_reset(AACContext *ac, SpectralBandReplication *sbr)
 {
     int err;
     err = sbr_make_f_master(ac, sbr, &sbr->spectrum_params);
     if (err >= 0)
         err = sbr_make_f_derived(ac, sbr);
     if (err < 0) {
         av_log(ac->avctx, AV_LOG_ERROR,
                "SBR reset failed. Switching SBR to pure upsampling mode.\n");
         sbr_turnoff(sbr);
     }
 }
 
 /**
  * Decode Spectral Band Replication extension data; reference: table 4.55.
  *
  * @param   crc flag indicating the presence of CRC checksum
  * @param   cnt length of TYPE_FIL syntactic element in bytes
  *
  * @return  Returns number of bytes consumed from the TYPE_FIL element.
  */

 int AAC_RENAME(ff_decode_sbr_extension)(AACContext *ac, SpectralBandReplication *sbr,

                             GetBitContext *gb_host, int crc, int cnt, int id_aac)
 {
     unsigned int num_sbr_bits = 0, num_align_bits;
     unsigned bytes_read;
     GetBitContext gbc = *gb_host, *gb = &gbc;
     skip_bits_long(gb_host, cnt*8 - 4);
 
     sbr->reset = 0;
 
     if (!sbr->sample_rate)
         sbr->sample_rate = 2 * ac->oc[1].m4ac.sample_rate; //TODO use the nominal sample rate for arbitrary sample rate support
     if (!ac->oc[1].m4ac.ext_sample_rate)
         ac->oc[1].m4ac.ext_sample_rate = 2 * ac->oc[1].m4ac.sample_rate;
 
     if (crc) {
         skip_bits(gb, 10); // bs_sbr_crc_bits; TODO - implement CRC check
         num_sbr_bits += 10;
     }
 
     //Save some state from the previous frame.
     sbr->kx[0] = sbr->kx[1];
     sbr->m[0] = sbr->m[1];
     sbr->kx_and_m_pushed = 1;
 
     num_sbr_bits++;
     if (get_bits1(gb)) // bs_header_flag
         num_sbr_bits += read_sbr_header(sbr, gb);
 
     if (sbr->reset)
         sbr_reset(ac, sbr);
 
     if (sbr->start)
         num_sbr_bits  += read_sbr_data(ac, sbr, gb, id_aac);
 
     num_align_bits = ((cnt << 3) - 4 - num_sbr_bits) & 7;
     bytes_read = ((num_sbr_bits + num_align_bits + 4) >> 3);
 
     if (bytes_read > cnt) {
         av_log(ac->avctx, AV_LOG_ERROR,
                "Expected to read %d SBR bytes actually read %d.\n", cnt, bytes_read);

         sbr_turnoff(sbr);

     }
     return cnt;
 }
 
 /**
  * Analysis QMF Bank (14496-3 sp04 p206)
  *
  * @param   x       pointer to the beginning of the first sample window
  * @param   W       array of complex-valued samples split into subbands
  */
 #ifndef sbr_qmf_analysis

 #if USE_FIXED
 static void sbr_qmf_analysis(AVFixedDSPContext *dsp, FFTContext *mdct,
 #else

 static void sbr_qmf_analysis(AVFloatDSPContext *dsp, FFTContext *mdct,

 #endif /* USE_FIXED */
                              SBRDSPContext *sbrdsp, const INTFLOAT *in, INTFLOAT *x,
                              INTFLOAT z[320], INTFLOAT W[2][32][32][2], int buf_idx)

 {
     int i;

 #if USE_FIXED
     int j;
 #endif

     memcpy(x    , x+1024, (320-32)*sizeof(x[0]));
     memcpy(x+288, in,         1024*sizeof(x[0]));
     for (i = 0; i < 32; i++) { // numTimeSlots*RATE = 16*2 as 960 sample frames
                                // are not supported
         dsp->vector_fmul_reverse(z, sbr_qmf_window_ds, x, 320);
         sbrdsp->sum64x5(z);
         sbrdsp->qmf_pre_shuffle(z);

 #if USE_FIXED
         for (j = 64; j < 128; j++) {
             if (z[j] > 1<<24) {
                 av_log(NULL, AV_LOG_WARNING,
                        "sbr_qmf_analysis: value %09d too large, setting to %09d\n",
                        z[j], 1<<24);
                 z[j] = 1<<24;
             } else if (z[j] < -(1<<24)) {
                 av_log(NULL, AV_LOG_WARNING,
                        "sbr_qmf_analysis: value %09d too small, setting to %09d\n",
                        z[j], -(1<<24));
                 z[j] = -(1<<24);
             }
         }
 #endif

         mdct->imdct_half(mdct, z, z+64);
         sbrdsp->qmf_post_shuffle(W[buf_idx][i], z);
         x += 32;
     }
 }
 #endif
 
 /**
  * Synthesis QMF Bank (14496-3 sp04 p206) and Downsampled Synthesis QMF Bank
  * (14496-3 sp04 p206)
  */
 #ifndef sbr_qmf_synthesis
 static void sbr_qmf_synthesis(FFTContext *mdct,

 #if USE_FIXED
                               SBRDSPContext *sbrdsp, AVFixedDSPContext *dsp,
 #else

                               SBRDSPContext *sbrdsp, AVFloatDSPContext *dsp,

 #endif /* USE_FIXED */
                               INTFLOAT *out, INTFLOAT X[2][38][64],
                               INTFLOAT mdct_buf[2][64],
                               INTFLOAT *v0, int *v_off, const unsigned int div)

 {
     int i, n;

     const INTFLOAT *sbr_qmf_window = div ? sbr_qmf_window_ds : sbr_qmf_window_us;

     const int step = 128 >> div;

     INTFLOAT *v;

     for (i = 0; i < 32; i++) {
         if (*v_off < step) {
             int saved_samples = (1280 - 128) >> div;

             memcpy(&v0[SBR_SYNTHESIS_BUF_SIZE - saved_samples], v0, saved_samples * sizeof(INTFLOAT));

             *v_off = SBR_SYNTHESIS_BUF_SIZE - saved_samples - step;
         } else {
             *v_off -= step;
         }
         v = v0 + *v_off;
         if (div) {
             for (n = 0; n < 32; n++) {
                 X[0][i][   n] = -X[0][i][n];
                 X[0][i][32+n] =  X[1][i][31-n];
             }
             mdct->imdct_half(mdct, mdct_buf[0], X[0][i]);
             sbrdsp->qmf_deint_neg(v, mdct_buf[0]);
         } else {
             sbrdsp->neg_odd_64(X[1][i]);
             mdct->imdct_half(mdct, mdct_buf[0], X[0][i]);
             mdct->imdct_half(mdct, mdct_buf[1], X[1][i]);
             sbrdsp->qmf_deint_bfly(v, mdct_buf[1], mdct_buf[0]);
         }
         dsp->vector_fmul    (out, v                , sbr_qmf_window                       , 64 >> div);
         dsp->vector_fmul_add(out, v + ( 192 >> div), sbr_qmf_window + ( 64 >> div), out   , 64 >> div);
         dsp->vector_fmul_add(out, v + ( 256 >> div), sbr_qmf_window + (128 >> div), out   , 64 >> div);
         dsp->vector_fmul_add(out, v + ( 448 >> div), sbr_qmf_window + (192 >> div), out   , 64 >> div);
         dsp->vector_fmul_add(out, v + ( 512 >> div), sbr_qmf_window + (256 >> div), out   , 64 >> div);
         dsp->vector_fmul_add(out, v + ( 704 >> div), sbr_qmf_window + (320 >> div), out   , 64 >> div);
         dsp->vector_fmul_add(out, v + ( 768 >> div), sbr_qmf_window + (384 >> div), out   , 64 >> div);
         dsp->vector_fmul_add(out, v + ( 960 >> div), sbr_qmf_window + (448 >> div), out   , 64 >> div);
         dsp->vector_fmul_add(out, v + (1024 >> div), sbr_qmf_window + (512 >> div), out   , 64 >> div);
         dsp->vector_fmul_add(out, v + (1216 >> div), sbr_qmf_window + (576 >> div), out   , 64 >> div);
         out += 64 >> div;
     }
 }
 #endif
 
 /// Generate the subband filtered lowband
 static int sbr_lf_gen(AACContext *ac, SpectralBandReplication *sbr,

                       INTFLOAT X_low[32][40][2], const INTFLOAT W[2][32][32][2],

                       int buf_idx)
 {
     int i, k;
     const int t_HFGen = 8;
     const int i_f = 32;
     memset(X_low, 0, 32*sizeof(*X_low));
     for (k = 0; k < sbr->kx[1]; k++) {
         for (i = t_HFGen; i < i_f + t_HFGen; i++) {
             X_low[k][i][0] = W[buf_idx][i - t_HFGen][k][0];
             X_low[k][i][1] = W[buf_idx][i - t_HFGen][k][1];
         }
     }
     buf_idx = 1-buf_idx;
     for (k = 0; k < sbr->kx[0]; k++) {
         for (i = 0; i < t_HFGen; i++) {
             X_low[k][i][0] = W[buf_idx][i + i_f - t_HFGen][k][0];
             X_low[k][i][1] = W[buf_idx][i + i_f - t_HFGen][k][1];
         }
     }
     return 0;
 }
 
 /// High Frequency Generator (14496-3 sp04 p215)
 static int sbr_hf_gen(AACContext *ac, SpectralBandReplication *sbr,

                       INTFLOAT X_high[64][40][2], const INTFLOAT X_low[32][40][2],
                       const INTFLOAT (*alpha0)[2], const INTFLOAT (*alpha1)[2],
                       const INTFLOAT bw_array[5], const uint8_t *t_env,

                       int bs_num_env)
 {
     int j, x;
     int g = 0;
     int k = sbr->kx[1];
     for (j = 0; j < sbr->num_patches; j++) {
         for (x = 0; x < sbr->patch_num_subbands[j]; x++, k++) {
             const int p = sbr->patch_start_subband[j] + x;
             while (g <= sbr->n_q && k >= sbr->f_tablenoise[g])
                 g++;
             g--;
 
             if (g < 0) {
                 av_log(ac->avctx, AV_LOG_ERROR,
                        "ERROR : no subband found for frequency %d\n", k);
                 return -1;
             }
 
             sbr->dsp.hf_gen(X_high[k] + ENVELOPE_ADJUSTMENT_OFFSET,
                             X_low[p]  + ENVELOPE_ADJUSTMENT_OFFSET,
                             alpha0[p], alpha1[p], bw_array[g],
                             2 * t_env[0], 2 * t_env[bs_num_env]);
         }
     }
     if (k < sbr->m[1] + sbr->kx[1])
         memset(X_high + k, 0, (sbr->m[1] + sbr->kx[1] - k) * sizeof(*X_high));
 
     return 0;
 }
 
 /// Generate the subband filtered lowband

 static int sbr_x_gen(SpectralBandReplication *sbr, INTFLOAT X[2][38][64],
                      const INTFLOAT Y0[38][64][2], const INTFLOAT Y1[38][64][2],
                      const INTFLOAT X_low[32][40][2], int ch)

 {
     int k, i;
     const int i_f = 32;
     const int i_Temp = FFMAX(2*sbr->data[ch].t_env_num_env_old - i_f, 0);
     memset(X, 0, 2*sizeof(*X));
     for (k = 0; k < sbr->kx[0]; k++) {
         for (i = 0; i < i_Temp; i++) {
             X[0][i][k] = X_low[k][i + ENVELOPE_ADJUSTMENT_OFFSET][0];
             X[1][i][k] = X_low[k][i + ENVELOPE_ADJUSTMENT_OFFSET][1];
         }
     }
     for (; k < sbr->kx[0] + sbr->m[0]; k++) {
         for (i = 0; i < i_Temp; i++) {
             X[0][i][k] = Y0[i + i_f][k][0];
             X[1][i][k] = Y0[i + i_f][k][1];
         }
     }
 
     for (k = 0; k < sbr->kx[1]; k++) {
         for (i = i_Temp; i < 38; i++) {
             X[0][i][k] = X_low[k][i + ENVELOPE_ADJUSTMENT_OFFSET][0];
             X[1][i][k] = X_low[k][i + ENVELOPE_ADJUSTMENT_OFFSET][1];
         }
     }
     for (; k < sbr->kx[1] + sbr->m[1]; k++) {
         for (i = i_Temp; i < i_f; i++) {
             X[0][i][k] = Y1[i][k][0];
             X[1][i][k] = Y1[i][k][1];
         }
     }
     return 0;
 }
 
 /** High Frequency Adjustment (14496-3 sp04 p217) and Mapping
  * (14496-3 sp04 p217)
  */
 static int sbr_mapping(AACContext *ac, SpectralBandReplication *sbr,
                         SBRData *ch_data, int e_a[2])
 {
     int e, i, m;
 
     memset(ch_data->s_indexmapped[1], 0, 7*sizeof(ch_data->s_indexmapped[1]));
     for (e = 0; e < ch_data->bs_num_env; e++) {
         const unsigned int ilim = sbr->n[ch_data->bs_freq_res[e + 1]];
         uint16_t *table = ch_data->bs_freq_res[e + 1] ? sbr->f_tablehigh : sbr->f_tablelow;
         int k;
 
         if (sbr->kx[1] != table[0]) {
             av_log(ac->avctx, AV_LOG_ERROR, "kx != f_table{high,low}[0]. "
                    "Derived frequency tables were not regenerated.\n");
             sbr_turnoff(sbr);
             return AVERROR_BUG;
         }
         for (i = 0; i < ilim; i++)
             for (m = table[i]; m < table[i + 1]; m++)
                 sbr->e_origmapped[e][m - sbr->kx[1]] = ch_data->env_facs[e+1][i];
 
         // ch_data->bs_num_noise > 1 => 2 noise floors
         k = (ch_data->bs_num_noise > 1) && (ch_data->t_env[e] >= ch_data->t_q[1]);
         for (i = 0; i < sbr->n_q; i++)
             for (m = sbr->f_tablenoise[i]; m < sbr->f_tablenoise[i + 1]; m++)
                 sbr->q_mapped[e][m - sbr->kx[1]] = ch_data->noise_facs[k+1][i];
 
         for (i = 0; i < sbr->n[1]; i++) {
             if (ch_data->bs_add_harmonic_flag) {
                 const unsigned int m_midpoint =
                     (sbr->f_tablehigh[i] + sbr->f_tablehigh[i + 1]) >> 1;
 
                 ch_data->s_indexmapped[e + 1][m_midpoint - sbr->kx[1]] = ch_data->bs_add_harmonic[i] *
                     (e >= e_a[1] || (ch_data->s_indexmapped[0][m_midpoint - sbr->kx[1]] == 1));
             }
         }
 
         for (i = 0; i < ilim; i++) {
             int additional_sinusoid_present = 0;
             for (m = table[i]; m < table[i + 1]; m++) {
                 if (ch_data->s_indexmapped[e + 1][m - sbr->kx[1]]) {
                     additional_sinusoid_present = 1;
                     break;
                 }
             }
             memset(&sbr->s_mapped[e][table[i] - sbr->kx[1]], additional_sinusoid_present,
                    (table[i + 1] - table[i]) * sizeof(sbr->s_mapped[e][0]));
         }
     }
 
     memcpy(ch_data->s_indexmapped[0], ch_data->s_indexmapped[ch_data->bs_num_env], sizeof(ch_data->s_indexmapped[0]));
     return 0;
 }
 
 /// Estimation of current envelope (14496-3 sp04 p218)

 static void sbr_env_estimate(AAC_FLOAT (*e_curr)[48], INTFLOAT X_high[64][40][2],

                              SpectralBandReplication *sbr, SBRData *ch_data)
 {
     int e, m;
     int kx1 = sbr->kx[1];
 
     if (sbr->bs_interpol_freq) {
         for (e = 0; e < ch_data->bs_num_env; e++) {

 #if USE_FIXED
             const SoftFloat recip_env_size = av_int2sf(0x20000000 / (ch_data->t_env[e + 1] - ch_data->t_env[e]), 30);
 #else

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

 #endif /* USE_FIXED */

             int ilb = ch_data->t_env[e]     * 2 + ENVELOPE_ADJUSTMENT_OFFSET;
             int iub = ch_data->t_env[e + 1] * 2 + ENVELOPE_ADJUSTMENT_OFFSET;
 
             for (m = 0; m < sbr->m[1]; m++) {

                 AAC_FLOAT sum = sbr->dsp.sum_square(X_high[m+kx1] + ilb, iub - ilb);
 #if USE_FIXED
                 e_curr[e][m] = av_mul_sf(sum, recip_env_size);
 #else

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

 #endif /* USE_FIXED */

             }
         }
     } else {
         int k, p;
 
         for (e = 0; e < ch_data->bs_num_env; e++) {
             const int env_size = 2 * (ch_data->t_env[e + 1] - ch_data->t_env[e]);
             int ilb = ch_data->t_env[e]     * 2 + ENVELOPE_ADJUSTMENT_OFFSET;
             int iub = ch_data->t_env[e + 1] * 2 + ENVELOPE_ADJUSTMENT_OFFSET;
             const uint16_t *table = ch_data->bs_freq_res[e + 1] ? sbr->f_tablehigh : sbr->f_tablelow;
 
             for (p = 0; p < sbr->n[ch_data->bs_freq_res[e + 1]]; p++) {

 #if USE_FIXED

                 SoftFloat sum = FLOAT_0;

                 const SoftFloat den = av_int2sf(0x20000000 / (env_size * (table[p + 1] - table[p])), 29);
                 for (k = table[p]; k < table[p + 1]; k++) {
                     sum = av_add_sf(sum, sbr->dsp.sum_square(X_high[k] + ilb, iub - ilb));
                 }
                 sum = av_mul_sf(sum, den);
 #else

                 float sum = 0.0f;
                 const int den = env_size * (table[p + 1] - table[p]);
 
                 for (k = table[p]; k < table[p + 1]; k++) {
                     sum += sbr->dsp.sum_square(X_high[k] + ilb, iub - ilb);
                 }
                 sum /= den;

 #endif /* USE_FIXED */

                 for (k = table[p]; k < table[p + 1]; k++) {
                     e_curr[e][k - kx1] = sum;
                 }
             }
         }
     }
 }
 

 void AAC_RENAME(ff_sbr_apply)(AACContext *ac, SpectralBandReplication *sbr, int id_aac,
                   INTFLOAT* L, INTFLOAT* R)

 {
     int downsampled = ac->oc[1].m4ac.ext_sample_rate < sbr->sample_rate;
     int ch;
     int nch = (id_aac == TYPE_CPE) ? 2 : 1;
     int err;
 
     if (id_aac != sbr->id_aac) {

         av_log(ac->avctx, id_aac == TYPE_LFE ? AV_LOG_VERBOSE : AV_LOG_WARNING,

             "element type mismatch %d != %d\n", id_aac, sbr->id_aac);
         sbr_turnoff(sbr);
     }
 

     if (sbr->start && !sbr->ready_for_dequant) {
         av_log(ac->avctx, AV_LOG_ERROR,
                "No quantized data read for sbr_dequant.\n");
         sbr_turnoff(sbr);
     }
 

     if (!sbr->kx_and_m_pushed) {
         sbr->kx[0] = sbr->kx[1];
         sbr->m[0] = sbr->m[1];
     } else {
         sbr->kx_and_m_pushed = 0;
     }
 
     if (sbr->start) {
         sbr_dequant(sbr, id_aac);

         sbr->ready_for_dequant = 0;

     }
     for (ch = 0; ch < nch; ch++) {
         /* decode channel */
         sbr_qmf_analysis(ac->fdsp, &sbr->mdct_ana, &sbr->dsp, ch ? R : L, sbr->data[ch].analysis_filterbank_samples,

                          (INTFLOAT*)sbr->qmf_filter_scratch,

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

                           (const INTFLOAT (*)[32][32][2]) sbr->data[ch].W,

                           sbr->data[ch].Ypos);
         sbr->data[ch].Ypos ^= 1;
         if (sbr->start) {
             sbr->c.sbr_hf_inverse_filter(&sbr->dsp, sbr->alpha0, sbr->alpha1,

                                          (const INTFLOAT (*)[40][2]) sbr->X_low, sbr->k[0]);

             sbr_chirp(sbr, &sbr->data[ch]);
             av_assert0(sbr->data[ch].bs_num_env > 0);
             sbr_hf_gen(ac, sbr, sbr->X_high,

                        (const INTFLOAT (*)[40][2]) sbr->X_low,
                        (const INTFLOAT (*)[2]) sbr->alpha0,
                        (const INTFLOAT (*)[2]) sbr->alpha1,

                        sbr->data[ch].bw_array, sbr->data[ch].t_env,
                        sbr->data[ch].bs_num_env);
 
             // hf_adj
             err = sbr_mapping(ac, sbr, &sbr->data[ch], sbr->data[ch].e_a);
             if (!err) {
                 sbr_env_estimate(sbr->e_curr, sbr->X_high, sbr, &sbr->data[ch]);
                 sbr_gain_calc(ac, sbr, &sbr->data[ch], sbr->data[ch].e_a);
                 sbr->c.sbr_hf_assemble(sbr->data[ch].Y[sbr->data[ch].Ypos],

                                 (const INTFLOAT (*)[40][2]) sbr->X_high,

                                 sbr, &sbr->data[ch],
                                 sbr->data[ch].e_a);
             }
         }
 
         /* synthesis */
         sbr->c.sbr_x_gen(sbr, sbr->X[ch],

                   (const INTFLOAT (*)[64][2]) sbr->data[ch].Y[1-sbr->data[ch].Ypos],
                   (const INTFLOAT (*)[64][2]) sbr->data[ch].Y[  sbr->data[ch].Ypos],
                   (const INTFLOAT (*)[40][2]) sbr->X_low, ch);

     }
 
     if (ac->oc[1].m4ac.ps == 1) {
         if (sbr->ps.start) {

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

         } else {
             memcpy(sbr->X[1], sbr->X[0], sizeof(sbr->X[0]));
         }
         nch = 2;
     }
 
     sbr_qmf_synthesis(&sbr->mdct, &sbr->dsp, ac->fdsp,
                       L, sbr->X[0], sbr->qmf_filter_scratch,
                       sbr->data[0].synthesis_filterbank_samples,
                       &sbr->data[0].synthesis_filterbank_samples_offset,
                       downsampled);
     if (nch == 2)
         sbr_qmf_synthesis(&sbr->mdct, &sbr->dsp, ac->fdsp,
                           R, sbr->X[1], sbr->qmf_filter_scratch,
                           sbr->data[1].synthesis_filterbank_samples,
                           &sbr->data[1].synthesis_filterbank_samples_offset,
                           downsampled);
 }
 
 static void aacsbr_func_ptr_init(AACSBRContext *c)
 {
     c->sbr_lf_gen            = sbr_lf_gen;
     c->sbr_hf_assemble       = sbr_hf_assemble;
     c->sbr_x_gen             = sbr_x_gen;
     c->sbr_hf_inverse_filter = sbr_hf_inverse_filter;
 

 #if !USE_FIXED

     if(ARCH_MIPS)
         ff_aacsbr_func_ptr_init_mips(c);

 #endif

 }