LCOV - code coverage report
Current view: top level - src/libavcodec - ac3dec.c (source / functions) Hit Total Coverage
Test: coverage.info Lines: 726 903 80.4 %
Date: 2017-07-21 15:41:20 Functions: 23 23 100.0 %

          Line data    Source code
       1             : /*
       2             :  * AC-3 Audio Decoder
       3             :  * This code was developed as part of Google Summer of Code 2006.
       4             :  * E-AC-3 support was added as part of Google Summer of Code 2007.
       5             :  *
       6             :  * Copyright (c) 2006 Kartikey Mahendra BHATT (bhattkm at gmail dot com)
       7             :  * Copyright (c) 2007-2008 Bartlomiej Wolowiec <bartek.wolowiec@gmail.com>
       8             :  * Copyright (c) 2007 Justin Ruggles <justin.ruggles@gmail.com>
       9             :  *
      10             :  * This file is part of FFmpeg.
      11             :  *
      12             :  * FFmpeg is free software; you can redistribute it and/or
      13             :  * modify it under the terms of the GNU Lesser General Public
      14             :  * License as published by the Free Software Foundation; either
      15             :  * version 2.1 of the License, or (at your option) any later version.
      16             :  *
      17             :  * FFmpeg is distributed in the hope that it will be useful,
      18             :  * but WITHOUT ANY WARRANTY; without even the implied warranty of
      19             :  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      20             :  * Lesser General Public License for more details.
      21             :  *
      22             :  * You should have received a copy of the GNU Lesser General Public
      23             :  * License along with FFmpeg; if not, write to the Free Software
      24             :  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
      25             :  */
      26             : 
      27             : #include <stdio.h>
      28             : #include <stddef.h>
      29             : #include <math.h>
      30             : #include <string.h>
      31             : 
      32             : #include "libavutil/channel_layout.h"
      33             : #include "libavutil/crc.h"
      34             : #include "libavutil/downmix_info.h"
      35             : #include "libavutil/opt.h"
      36             : #include "bswapdsp.h"
      37             : #include "internal.h"
      38             : #include "aac_ac3_parser.h"
      39             : #include "ac3_parser.h"
      40             : #include "ac3dec.h"
      41             : #include "ac3dec_data.h"
      42             : #include "kbdwin.h"
      43             : 
      44             : /**
      45             :  * table for ungrouping 3 values in 7 bits.
      46             :  * used for exponents and bap=2 mantissas
      47             :  */
      48             : static uint8_t ungroup_3_in_7_bits_tab[128][3];
      49             : 
      50             : /** tables for ungrouping mantissas */
      51             : static int b1_mantissas[32][3];
      52             : static int b2_mantissas[128][3];
      53             : static int b3_mantissas[8];
      54             : static int b4_mantissas[128][2];
      55             : static int b5_mantissas[16];
      56             : 
      57             : /**
      58             :  * Quantization table: levels for symmetric. bits for asymmetric.
      59             :  * reference: Table 7.18 Mapping of bap to Quantizer
      60             :  */
      61             : static const uint8_t quantization_tab[16] = {
      62             :     0, 3, 5, 7, 11, 15,
      63             :     5, 6, 7, 8, 9, 10, 11, 12, 14, 16
      64             : };
      65             : 
      66             : #if (!USE_FIXED)
      67             : /** dynamic range table. converts codes to scale factors. */
      68             : static float dynamic_range_tab[256];
      69             : float ff_ac3_heavy_dynamic_range_tab[256];
      70             : #endif
      71             : 
      72             : /** Adjustments in dB gain */
      73             : static const float gain_levels[9] = {
      74             :     LEVEL_PLUS_3DB,
      75             :     LEVEL_PLUS_1POINT5DB,
      76             :     LEVEL_ONE,
      77             :     LEVEL_MINUS_1POINT5DB,
      78             :     LEVEL_MINUS_3DB,
      79             :     LEVEL_MINUS_4POINT5DB,
      80             :     LEVEL_MINUS_6DB,
      81             :     LEVEL_ZERO,
      82             :     LEVEL_MINUS_9DB
      83             : };
      84             : 
      85             : /** Adjustments in dB gain (LFE, +10 to -21 dB) */
      86             : static const float gain_levels_lfe[32] = {
      87             :     3.162275, 2.818382, 2.511886, 2.238719, 1.995261, 1.778278, 1.584893,
      88             :     1.412536, 1.258924, 1.122018, 1.000000, 0.891251, 0.794328, 0.707946,
      89             :     0.630957, 0.562341, 0.501187, 0.446683, 0.398107, 0.354813, 0.316227,
      90             :     0.281838, 0.251188, 0.223872, 0.199526, 0.177828, 0.158489, 0.141253,
      91             :     0.125892, 0.112201, 0.100000, 0.089125
      92             : };
      93             : 
      94             : /**
      95             :  * Table for default stereo downmixing coefficients
      96             :  * reference: Section 7.8.2 Downmixing Into Two Channels
      97             :  */
      98             : static const uint8_t ac3_default_coeffs[8][5][2] = {
      99             :     { { 2, 7 }, { 7, 2 },                               },
     100             :     { { 4, 4 },                                         },
     101             :     { { 2, 7 }, { 7, 2 },                               },
     102             :     { { 2, 7 }, { 5, 5 }, { 7, 2 },                     },
     103             :     { { 2, 7 }, { 7, 2 }, { 6, 6 },                     },
     104             :     { { 2, 7 }, { 5, 5 }, { 7, 2 }, { 8, 8 },           },
     105             :     { { 2, 7 }, { 7, 2 }, { 6, 7 }, { 7, 6 },           },
     106             :     { { 2, 7 }, { 5, 5 }, { 7, 2 }, { 6, 7 }, { 7, 6 }, },
     107             : };
     108             : 
     109             : /**
     110             :  * Symmetrical Dequantization
     111             :  * reference: Section 7.3.3 Expansion of Mantissas for Symmetrical Quantization
     112             :  *            Tables 7.19 to 7.23
     113             :  */
     114             : static inline int
     115       31836 : symmetric_dequant(int code, int levels)
     116             : {
     117       31836 :     return ((code - (levels >> 1)) * (1 << 24)) / levels;
     118             : }
     119             : 
     120             : /*
     121             :  * Initialize tables at runtime.
     122             :  */
     123          42 : static av_cold void ac3_tables_init(void)
     124             : {
     125             :     int i;
     126             : 
     127             :     /* generate table for ungrouping 3 values in 7 bits
     128             :        reference: Section 7.1.3 Exponent Decoding */
     129        5418 :     for (i = 0; i < 128; i++) {
     130        5376 :         ungroup_3_in_7_bits_tab[i][0] =  i / 25;
     131        5376 :         ungroup_3_in_7_bits_tab[i][1] = (i % 25) / 5;
     132        5376 :         ungroup_3_in_7_bits_tab[i][2] = (i % 25) % 5;
     133             :     }
     134             : 
     135             :     /* generate grouped mantissa tables
     136             :        reference: Section 7.3.5 Ungrouping of Mantissas */
     137        1386 :     for (i = 0; i < 32; i++) {
     138             :         /* bap=1 mantissas */
     139        1344 :         b1_mantissas[i][0] = symmetric_dequant(ff_ac3_ungroup_3_in_5_bits_tab[i][0], 3);
     140        1344 :         b1_mantissas[i][1] = symmetric_dequant(ff_ac3_ungroup_3_in_5_bits_tab[i][1], 3);
     141        1344 :         b1_mantissas[i][2] = symmetric_dequant(ff_ac3_ungroup_3_in_5_bits_tab[i][2], 3);
     142             :     }
     143        5418 :     for (i = 0; i < 128; i++) {
     144             :         /* bap=2 mantissas */
     145        5376 :         b2_mantissas[i][0] = symmetric_dequant(ungroup_3_in_7_bits_tab[i][0], 5);
     146        5376 :         b2_mantissas[i][1] = symmetric_dequant(ungroup_3_in_7_bits_tab[i][1], 5);
     147        5376 :         b2_mantissas[i][2] = symmetric_dequant(ungroup_3_in_7_bits_tab[i][2], 5);
     148             : 
     149             :         /* bap=4 mantissas */
     150        5376 :         b4_mantissas[i][0] = symmetric_dequant(i / 11, 11);
     151        5376 :         b4_mantissas[i][1] = symmetric_dequant(i % 11, 11);
     152             :     }
     153             :     /* generate ungrouped mantissa tables
     154             :        reference: Tables 7.21 and 7.23 */
     155         336 :     for (i = 0; i < 7; i++) {
     156             :         /* bap=3 mantissas */
     157         294 :         b3_mantissas[i] = symmetric_dequant(i, 7);
     158             :     }
     159         672 :     for (i = 0; i < 15; i++) {
     160             :         /* bap=5 mantissas */
     161         630 :         b5_mantissas[i] = symmetric_dequant(i, 15);
     162             :     }
     163             : 
     164             : #if (!USE_FIXED)
     165             :     /* generate dynamic range table
     166             :        reference: Section 7.7.1 Dynamic Range Control */
     167        9766 :     for (i = 0; i < 256; i++) {
     168        9728 :         int v = (i >> 5) - ((i >> 7) << 3) - 5;
     169        9728 :         dynamic_range_tab[i] = powf(2.0f, v) * ((i & 0x1F) | 0x20);
     170             :     }
     171             : 
     172             :     /* generate compr dynamic range table
     173             :        reference: Section 7.7.2 Heavy Compression */
     174        9766 :     for (i = 0; i < 256; i++) {
     175        9728 :         int v = (i >> 4) - ((i >> 7) << 4) - 4;
     176        9728 :         ff_ac3_heavy_dynamic_range_tab[i] = powf(2.0f, v) * ((i & 0xF) | 0x10);
     177             :     }
     178             : #endif
     179          42 : }
     180             : 
     181             : /**
     182             :  * AVCodec initialization
     183             :  */
     184          42 : static av_cold int ac3_decode_init(AVCodecContext *avctx)
     185             : {
     186          42 :     AC3DecodeContext *s = avctx->priv_data;
     187             :     int i;
     188             : 
     189          42 :     s->avctx = avctx;
     190             : 
     191          42 :     ac3_tables_init();
     192          42 :     ff_mdct_init(&s->imdct_256, 8, 1, 1.0);
     193          42 :     ff_mdct_init(&s->imdct_512, 9, 1, 1.0);
     194          42 :     AC3_RENAME(ff_kbd_window_init)(s->window, 5.0, 256);
     195          42 :     ff_bswapdsp_init(&s->bdsp);
     196             : 
     197             : #if (USE_FIXED)
     198           4 :     s->fdsp = avpriv_alloc_fixed_dsp(avctx->flags & AV_CODEC_FLAG_BITEXACT);
     199             : #else
     200          38 :     s->fdsp = avpriv_float_dsp_alloc(avctx->flags & AV_CODEC_FLAG_BITEXACT);
     201          38 :     ff_fmt_convert_init(&s->fmt_conv, avctx);
     202             : #endif
     203             : 
     204          42 :     ff_ac3dsp_init(&s->ac3dsp, avctx->flags & AV_CODEC_FLAG_BITEXACT);
     205          42 :     av_lfg_init(&s->dith_state, 0);
     206             : 
     207             :     if (USE_FIXED)
     208           4 :         avctx->sample_fmt = AV_SAMPLE_FMT_S16P;
     209             :     else
     210          38 :         avctx->sample_fmt = AV_SAMPLE_FMT_FLTP;
     211             : 
     212             :     /* allow downmixing to stereo or mono */
     213          59 :     if (avctx->channels > 1 &&
     214          17 :         avctx->request_channel_layout == AV_CH_LAYOUT_MONO)
     215           0 :         avctx->channels = 1;
     216          47 :     else if (avctx->channels > 2 &&
     217           5 :              avctx->request_channel_layout == AV_CH_LAYOUT_STEREO)
     218           0 :         avctx->channels = 2;
     219          42 :     s->downmixed = 1;
     220             : 
     221         336 :     for (i = 0; i < AC3_MAX_CHANNELS; i++) {
     222         294 :         s->xcfptr[i] = s->transform_coeffs[i];
     223         294 :         s->dlyptr[i] = s->delay[i];
     224             :     }
     225             : 
     226          42 :     return 0;
     227             : }
     228             : 
     229             : /**
     230             :  * Parse the 'sync info' and 'bit stream info' from the AC-3 bitstream.
     231             :  * GetBitContext within AC3DecodeContext must point to
     232             :  * the start of the synchronized AC-3 bitstream.
     233             :  */
     234        1072 : static int ac3_parse_header(AC3DecodeContext *s)
     235             : {
     236        1072 :     GetBitContext *gbc = &s->gbc;
     237             :     int i;
     238             : 
     239             :     /* read the rest of the bsi. read twice for dual mono mode. */
     240        1072 :     i = !s->channel_mode;
     241             :     do {
     242        1072 :         s->dialog_normalization[(!s->channel_mode)-i] = -get_bits(gbc, 5);
     243        1072 :         if (s->dialog_normalization[(!s->channel_mode)-i] == 0) {
     244           0 :             s->dialog_normalization[(!s->channel_mode)-i] = -31;
     245             :         }
     246        1072 :         if (s->target_level != 0) {
     247           0 :             s->level_gain[(!s->channel_mode)-i] = powf(2.0f,
     248           0 :                 (float)(s->target_level -
     249           0 :                 s->dialog_normalization[(!s->channel_mode)-i])/6.0f);
     250             :         }
     251        1072 :         if (s->compression_exists[(!s->channel_mode)-i] = get_bits1(gbc)) {
     252        1598 :             s->heavy_dynamic_range[(!s->channel_mode)-i] =
     253        1598 :                 AC3_HEAVY_RANGE(get_bits(gbc, 8));
     254             :         }
     255        1072 :         if (get_bits1(gbc))
     256           0 :             skip_bits(gbc, 8); //skip language code
     257        1072 :         if (get_bits1(gbc))
     258         547 :             skip_bits(gbc, 7); //skip audio production information
     259        1072 :     } while (i--);
     260             : 
     261        1072 :     skip_bits(gbc, 2); //skip copyright bit and original bitstream bit
     262             : 
     263             :     /* skip the timecodes or parse the Alternate Bit Stream Syntax */
     264        1072 :     if (s->bitstream_id != 6) {
     265        1072 :         if (get_bits1(gbc))
     266           0 :             skip_bits(gbc, 14); //skip timecode1
     267        1072 :         if (get_bits1(gbc))
     268           0 :             skip_bits(gbc, 14); //skip timecode2
     269             :     } else {
     270           0 :         if (get_bits1(gbc)) {
     271           0 :             s->preferred_downmix       = get_bits(gbc, 2);
     272           0 :             s->center_mix_level_ltrt   = get_bits(gbc, 3);
     273           0 :             s->surround_mix_level_ltrt = av_clip(get_bits(gbc, 3), 3, 7);
     274           0 :             s->center_mix_level        = get_bits(gbc, 3);
     275           0 :             s->surround_mix_level      = av_clip(get_bits(gbc, 3), 3, 7);
     276             :         }
     277           0 :         if (get_bits1(gbc)) {
     278           0 :             s->dolby_surround_ex_mode = get_bits(gbc, 2);
     279           0 :             s->dolby_headphone_mode   = get_bits(gbc, 2);
     280           0 :             skip_bits(gbc, 10); // skip adconvtyp (1), xbsi2 (8), encinfo (1)
     281             :         }
     282             :     }
     283             : 
     284             :     /* skip additional bitstream info */
     285        1072 :     if (get_bits1(gbc)) {
     286           0 :         i = get_bits(gbc, 6);
     287             :         do {
     288           0 :             skip_bits(gbc, 8);
     289           0 :         } while (i--);
     290             :     }
     291             : 
     292        1072 :     return 0;
     293             : }
     294             : 
     295             : /**
     296             :  * Common function to parse AC-3 or E-AC-3 frame header
     297             :  */
     298        2107 : static int parse_frame_header(AC3DecodeContext *s)
     299             : {
     300        2107 :     AC3HeaderInfo hdr, *phdr=&hdr;
     301             :     int err;
     302             : 
     303        2107 :     err = avpriv_ac3_parse_header(&s->gbc, &phdr);
     304        2107 :     if (err)
     305           0 :         return err;
     306             : 
     307             :     /* get decoding parameters from header info */
     308        2107 :     s->bit_alloc_params.sr_code     = hdr.sr_code;
     309        2107 :     s->bitstream_id                 = hdr.bitstream_id;
     310        2107 :     s->bitstream_mode               = hdr.bitstream_mode;
     311        2107 :     s->channel_mode                 = hdr.channel_mode;
     312        2107 :     s->lfe_on                       = hdr.lfe_on;
     313        2107 :     s->bit_alloc_params.sr_shift    = hdr.sr_shift;
     314        2107 :     s->sample_rate                  = hdr.sample_rate;
     315        2107 :     s->bit_rate                     = hdr.bit_rate;
     316        2107 :     s->channels                     = hdr.channels;
     317        2107 :     s->fbw_channels                 = s->channels - s->lfe_on;
     318        2107 :     s->lfe_ch                       = s->fbw_channels + 1;
     319        2107 :     s->frame_size                   = hdr.frame_size;
     320        2107 :     s->preferred_downmix            = AC3_DMIXMOD_NOTINDICATED;
     321        2107 :     s->center_mix_level             = hdr.center_mix_level;
     322        2107 :     s->center_mix_level_ltrt        = 4; // -3.0dB
     323        2107 :     s->surround_mix_level           = hdr.surround_mix_level;
     324        2107 :     s->surround_mix_level_ltrt      = 4; // -3.0dB
     325        2107 :     s->lfe_mix_level_exists         = 0;
     326        2107 :     s->num_blocks                   = hdr.num_blocks;
     327        2107 :     s->frame_type                   = hdr.frame_type;
     328        2107 :     s->substreamid                  = hdr.substreamid;
     329        2107 :     s->dolby_surround_mode          = hdr.dolby_surround_mode;
     330        2107 :     s->dolby_surround_ex_mode       = AC3_DSUREXMOD_NOTINDICATED;
     331        2107 :     s->dolby_headphone_mode         = AC3_DHEADPHONMOD_NOTINDICATED;
     332             : 
     333        2107 :     if (s->lfe_on) {
     334         429 :         s->start_freq[s->lfe_ch]     = 0;
     335         429 :         s->end_freq[s->lfe_ch]       = 7;
     336         429 :         s->num_exp_groups[s->lfe_ch] = 2;
     337         429 :         s->channel_in_cpl[s->lfe_ch] = 0;
     338             :     }
     339             : 
     340        2107 :     if (s->bitstream_id <= 10) {
     341        1072 :         s->eac3                  = 0;
     342        1072 :         s->snr_offset_strategy   = 2;
     343        1072 :         s->block_switch_syntax   = 1;
     344        1072 :         s->dither_flag_syntax    = 1;
     345        1072 :         s->bit_allocation_syntax = 1;
     346        1072 :         s->fast_gain_syntax      = 0;
     347        1072 :         s->first_cpl_leak        = 0;
     348        1072 :         s->dba_syntax            = 1;
     349        1072 :         s->skip_syntax           = 1;
     350        1072 :         memset(s->channel_uses_aht, 0, sizeof(s->channel_uses_aht));
     351        1072 :         return ac3_parse_header(s);
     352             :     } else if (CONFIG_EAC3_DECODER) {
     353        1035 :         s->eac3 = 1;
     354        1035 :         return ff_eac3_parse_header(s);
     355             :     } else {
     356             :         av_log(s->avctx, AV_LOG_ERROR, "E-AC-3 support not compiled in\n");
     357             :         return AVERROR(ENOSYS);
     358             :     }
     359             : }
     360             : 
     361             : /**
     362             :  * Set stereo downmixing coefficients based on frame header info.
     363             :  * reference: Section 7.8.2 Downmixing Into Two Channels
     364             :  */
     365         417 : static int set_downmix_coeffs(AC3DecodeContext *s)
     366             : {
     367             :     int i;
     368         417 :     float cmix = gain_levels[s->  center_mix_level];
     369         417 :     float smix = gain_levels[s->surround_mix_level];
     370             :     float norm0, norm1;
     371             :     float downmix_coeffs[2][AC3_MAX_CHANNELS];
     372             : 
     373         417 :     if (!s->downmix_coeffs[0]) {
     374          14 :         s->downmix_coeffs[0] = av_malloc_array(2 * AC3_MAX_CHANNELS,
     375             :                                                sizeof(**s->downmix_coeffs));
     376          14 :         if (!s->downmix_coeffs[0])
     377           0 :             return AVERROR(ENOMEM);
     378          14 :         s->downmix_coeffs[1] = s->downmix_coeffs[0] + AC3_MAX_CHANNELS;
     379             :     }
     380             : 
     381        2313 :     for (i = 0; i < s->fbw_channels; i++) {
     382        1896 :         downmix_coeffs[0][i] = gain_levels[ac3_default_coeffs[s->channel_mode][i][0]];
     383        1896 :         downmix_coeffs[1][i] = gain_levels[ac3_default_coeffs[s->channel_mode][i][1]];
     384             :     }
     385         417 :     if (s->channel_mode > 1 && s->channel_mode & 1) {
     386         417 :         downmix_coeffs[0][1] = downmix_coeffs[1][1] = cmix;
     387             :     }
     388         417 :     if (s->channel_mode == AC3_CHMODE_2F1R || s->channel_mode == AC3_CHMODE_3F1R) {
     389         189 :         int nf = s->channel_mode - 2;
     390         189 :         downmix_coeffs[0][nf] = downmix_coeffs[1][nf] = smix * LEVEL_MINUS_3DB;
     391             :     }
     392         417 :     if (s->channel_mode == AC3_CHMODE_2F2R || s->channel_mode == AC3_CHMODE_3F2R) {
     393         228 :         int nf = s->channel_mode - 4;
     394         228 :         downmix_coeffs[0][nf] = downmix_coeffs[1][nf+1] = smix;
     395             :     }
     396             : 
     397             :     /* renormalize */
     398         417 :     norm0 = norm1 = 0.0;
     399        2313 :     for (i = 0; i < s->fbw_channels; i++) {
     400        1896 :         norm0 += downmix_coeffs[0][i];
     401        1896 :         norm1 += downmix_coeffs[1][i];
     402             :     }
     403         417 :     norm0 = 1.0f / norm0;
     404         417 :     norm1 = 1.0f / norm1;
     405        2313 :     for (i = 0; i < s->fbw_channels; i++) {
     406        1896 :         downmix_coeffs[0][i] *= norm0;
     407        1896 :         downmix_coeffs[1][i] *= norm1;
     408             :     }
     409             : 
     410         417 :     if (s->output_mode == AC3_CHMODE_MONO) {
     411        1314 :         for (i = 0; i < s->fbw_channels; i++)
     412        3222 :             downmix_coeffs[0][i] = (downmix_coeffs[0][i] +
     413        2148 :                                     downmix_coeffs[1][i]) * LEVEL_MINUS_3DB;
     414             :     }
     415        2313 :     for (i = 0; i < s->fbw_channels; i++) {
     416        1896 :         s->downmix_coeffs[0][i] = FIXR12(downmix_coeffs[0][i]);
     417        1896 :         s->downmix_coeffs[1][i] = FIXR12(downmix_coeffs[1][i]);
     418             :     }
     419             : 
     420         417 :     return 0;
     421             : }
     422             : 
     423             : /**
     424             :  * Decode the grouped exponents according to exponent strategy.
     425             :  * reference: Section 7.1.3 Exponent Decoding
     426             :  */
     427       11072 : static int decode_exponents(AC3DecodeContext *s,
     428             :                             GetBitContext *gbc, int exp_strategy, int ngrps,
     429             :                             uint8_t absexp, int8_t *dexps)
     430             : {
     431             :     int i, j, grp, group_size;
     432             :     int dexp[256];
     433             :     int expacc, prevexp;
     434             : 
     435             :     /* unpack groups */
     436       11072 :     group_size = exp_strategy + (exp_strategy == EXP_D45);
     437      365189 :     for (grp = 0, i = 0; grp < ngrps; grp++) {
     438      354117 :         expacc = get_bits(gbc, 7);
     439      354117 :         if (expacc >= 125) {
     440           0 :             av_log(s->avctx, AV_LOG_ERROR, "expacc %d is out-of-range\n", expacc);
     441           0 :             return AVERROR_INVALIDDATA;
     442             :         }
     443      354117 :         dexp[i++] = ungroup_3_in_7_bits_tab[expacc][0];
     444      354117 :         dexp[i++] = ungroup_3_in_7_bits_tab[expacc][1];
     445      354117 :         dexp[i++] = ungroup_3_in_7_bits_tab[expacc][2];
     446             :     }
     447             : 
     448             :     /* convert to absolute exps and expand groups */
     449       11072 :     prevexp = absexp;
     450     1073423 :     for (i = 0, j = 0; i < ngrps * 3; i++) {
     451     1062351 :         prevexp += dexp[i] - 2;
     452     1062351 :         if (prevexp > 24U) {
     453           0 :             av_log(s->avctx, AV_LOG_ERROR, "exponent %d is out-of-range\n", prevexp);
     454           0 :             return -1;
     455             :         }
     456     1062351 :         switch (group_size) {
     457       78567 :         case 4: dexps[j++] = prevexp;
     458       78567 :                 dexps[j++] = prevexp;
     459      188847 :         case 2: dexps[j++] = prevexp;
     460     1062351 :         case 1: dexps[j++] = prevexp;
     461             :         }
     462             :     }
     463       11072 :     return 0;
     464             : }
     465             : 
     466             : /**
     467             :  * Generate transform coefficients for each coupled channel in the coupling
     468             :  * range using the coupling coefficients and coupling coordinates.
     469             :  * reference: Section 7.4.3 Coupling Coordinate Format
     470             :  */
     471        7292 : static void calc_transform_coeffs_cpl(AC3DecodeContext *s)
     472             : {
     473             :     int bin, band, ch;
     474             : 
     475        7292 :     bin = s->start_freq[CPL_CH];
     476       33100 :     for (band = 0; band < s->num_cpl_bands; band++) {
     477       25808 :         int band_start = bin;
     478       25808 :         int band_end = bin + s->cpl_band_sizes[band];
     479       87504 :         for (ch = 1; ch <= s->fbw_channels; ch++) {
     480       61696 :             if (s->channel_in_cpl[ch]) {
     481       61696 :                 int cpl_coord = s->cpl_coords[ch][band] << 5;
     482     1463392 :                 for (bin = band_start; bin < band_end; bin++) {
     483     1401696 :                     s->fixed_coeffs[ch][bin] =
     484     1401696 :                         MULH(s->fixed_coeffs[CPL_CH][bin] * (1 << 4), cpl_coord);
     485             :                 }
     486       61696 :                 if (ch == 2 && s->phase_flags[band]) {
     487           0 :                     for (bin = band_start; bin < band_end; bin++)
     488           0 :                         s->fixed_coeffs[2][bin] = -s->fixed_coeffs[2][bin];
     489             :                 }
     490             :             }
     491             :         }
     492       25808 :         bin = band_end;
     493             :     }
     494        7292 : }
     495             : 
     496             : /**
     497             :  * Grouped mantissas for 3-level 5-level and 11-level quantization
     498             :  */
     499             : typedef struct mant_groups {
     500             :     int b1_mant[2];
     501             :     int b2_mant[2];
     502             :     int b4_mant;
     503             :     int b1;
     504             :     int b2;
     505             :     int b4;
     506             : } mant_groups;
     507             : 
     508             : /**
     509             :  * Decode the transform coefficients for a particular channel
     510             :  * reference: Section 7.3 Quantization and Decoding of Mantissas
     511             :  */
     512       37994 : static void ac3_decode_transform_coeffs_ch(AC3DecodeContext *s, int ch_index, mant_groups *m)
     513             : {
     514       37994 :     int start_freq = s->start_freq[ch_index];
     515       37994 :     int end_freq   = s->end_freq[ch_index];
     516       37994 :     uint8_t *baps  = s->bap[ch_index];
     517       37994 :     int8_t *exps   = s->dexps[ch_index];
     518       37994 :     int32_t *coeffs = s->fixed_coeffs[ch_index];
     519       37994 :     int dither     = (ch_index == CPL_CH) || s->dither_flag[ch_index];
     520       37994 :     GetBitContext *gbc = &s->gbc;
     521             :     int freq;
     522             : 
     523     4831250 :     for (freq = start_freq; freq < end_freq; freq++) {
     524     4793256 :         int bap = baps[freq];
     525             :         int mantissa;
     526     4793256 :         switch (bap) {
     527     1377561 :         case 0:
     528             :             /* random noise with approximate range of -0.707 to 0.707 */
     529     1377561 :             if (dither)
     530     1373505 :                 mantissa = (((av_lfg_get(&s->dith_state)>>8)*181)>>8) - 5931008;
     531             :             else
     532        4056 :                 mantissa = 0;
     533     1377561 :             break;
     534     1101624 :         case 1:
     535     1101624 :             if (m->b1) {
     536      731044 :                 m->b1--;
     537      731044 :                 mantissa = m->b1_mant[m->b1];
     538             :             } else {
     539      370580 :                 int bits      = get_bits(gbc, 5);
     540      370580 :                 mantissa      = b1_mantissas[bits][0];
     541      370580 :                 m->b1_mant[1] = b1_mantissas[bits][1];
     542      370580 :                 m->b1_mant[0] = b1_mantissas[bits][2];
     543      370580 :                 m->b1         = 2;
     544             :             }
     545     1101624 :             break;
     546      452828 :         case 2:
     547      452828 :             if (m->b2) {
     548      298721 :                 m->b2--;
     549      298721 :                 mantissa = m->b2_mant[m->b2];
     550             :             } else {
     551      154107 :                 int bits      = get_bits(gbc, 7);
     552      154107 :                 mantissa      = b2_mantissas[bits][0];
     553      154107 :                 m->b2_mant[1] = b2_mantissas[bits][1];
     554      154107 :                 m->b2_mant[0] = b2_mantissas[bits][2];
     555      154107 :                 m->b2         = 2;
     556             :             }
     557      452828 :             break;
     558      600825 :         case 3:
     559      600825 :             mantissa = b3_mantissas[get_bits(gbc, 3)];
     560      600825 :             break;
     561      375138 :         case 4:
     562      375138 :             if (m->b4) {
     563      184998 :                 m->b4 = 0;
     564      184998 :                 mantissa = m->b4_mant;
     565             :             } else {
     566      190140 :                 int bits   = get_bits(gbc, 7);
     567      190140 :                 mantissa   = b4_mantissas[bits][0];
     568      190140 :                 m->b4_mant = b4_mantissas[bits][1];
     569      190140 :                 m->b4      = 1;
     570             :             }
     571      375138 :             break;
     572      288937 :         case 5:
     573      288937 :             mantissa = b5_mantissas[get_bits(gbc, 4)];
     574      288937 :             break;
     575      596343 :         default: /* 6 to 15 */
     576             :             /* Shift mantissa and sign-extend it. */
     577      596343 :             if (bap > 15) {
     578           0 :                 av_log(s->avctx, AV_LOG_ERROR, "bap %d is invalid in plain AC-3\n", bap);
     579           0 :                 bap = 15;
     580             :             }
     581      596343 :             mantissa = (unsigned)get_sbits(gbc, quantization_tab[bap]) << (24 - quantization_tab[bap]);
     582      596343 :             break;
     583             :         }
     584     4793256 :         coeffs[freq] = mantissa >> exps[freq];
     585             :     }
     586       37994 : }
     587             : 
     588             : /**
     589             :  * Remove random dithering from coupling range coefficients with zero-bit
     590             :  * mantissas for coupled channels which do not use dithering.
     591             :  * reference: Section 7.3.4 Dither for Zero Bit Mantissas (bap=0)
     592             :  */
     593       12115 : static void remove_dithering(AC3DecodeContext *s) {
     594             :     int ch, i;
     595             : 
     596       45546 :     for (ch = 1; ch <= s->fbw_channels; ch++) {
     597       33431 :         if (!s->dither_flag[ch] && s->channel_in_cpl[ch]) {
     598           0 :             for (i = s->start_freq[CPL_CH]; i < s->end_freq[CPL_CH]; i++) {
     599           0 :                 if (!s->bap[CPL_CH][i])
     600           0 :                     s->fixed_coeffs[ch][i] = 0;
     601             :             }
     602             :         }
     603             :     }
     604       12115 : }
     605             : 
     606       42782 : static inline void decode_transform_coeffs_ch(AC3DecodeContext *s, int blk,
     607             :                                               int ch, mant_groups *m)
     608             : {
     609       42782 :     if (!s->channel_uses_aht[ch]) {
     610       37994 :         ac3_decode_transform_coeffs_ch(s, ch, m);
     611             :     } else {
     612             :         /* if AHT is used, mantissas for all blocks are encoded in the first
     613             :            block of the frame. */
     614             :         int bin;
     615        4788 :         if (CONFIG_EAC3_DECODER && !blk)
     616         798 :             ff_eac3_decode_transform_coeffs_aht_ch(s, ch);
     617      591120 :         for (bin = s->start_freq[ch]; bin < s->end_freq[ch]; bin++) {
     618      586332 :             s->fixed_coeffs[ch][bin] = s->pre_mantissa[ch][bin][blk] >> s->dexps[ch][bin];
     619             :         }
     620             :     }
     621       42782 : }
     622             : 
     623             : /**
     624             :  * Decode the transform coefficients.
     625             :  */
     626       12115 : static inline void decode_transform_coeffs(AC3DecodeContext *s, int blk)
     627             : {
     628             :     int ch, end;
     629       12115 :     int got_cplchan = 0;
     630             :     mant_groups m;
     631             : 
     632       12115 :     m.b1 = m.b2 = m.b4 = 0;
     633             : 
     634       47605 :     for (ch = 1; ch <= s->channels; ch++) {
     635             :         /* transform coefficients for full-bandwidth channel */
     636       35490 :         decode_transform_coeffs_ch(s, blk, ch, &m);
     637             :         /* transform coefficients for coupling channel come right after the
     638             :            coefficients for the first coupled channel*/
     639       35490 :         if (s->channel_in_cpl[ch])  {
     640       19624 :             if (!got_cplchan) {
     641        7292 :                 decode_transform_coeffs_ch(s, blk, CPL_CH, &m);
     642        7292 :                 calc_transform_coeffs_cpl(s);
     643        7292 :                 got_cplchan = 1;
     644             :             }
     645       19624 :             end = s->end_freq[CPL_CH];
     646             :         } else {
     647       15866 :             end = s->end_freq[ch];
     648             :         }
     649             :         do
     650     2853804 :             s->fixed_coeffs[ch][end] = 0;
     651     2853804 :         while (++end < 256);
     652             :     }
     653             : 
     654             :     /* zero the dithered coefficients for appropriate channels */
     655       12115 :     remove_dithering(s);
     656       12115 : }
     657             : 
     658             : /**
     659             :  * Stereo rematrixing.
     660             :  * reference: Section 7.5.4 Rematrixing : Decoding Technique
     661             :  */
     662        8544 : static void do_rematrixing(AC3DecodeContext *s)
     663             : {
     664             :     int bnd, i;
     665             :     int end, bndend;
     666             : 
     667        8544 :     end = FFMIN(s->end_freq[1], s->end_freq[2]);
     668             : 
     669       42720 :     for (bnd = 0; bnd < s->num_rematrixing_bands; bnd++) {
     670       34176 :         if (s->rematrixing_flags[bnd]) {
     671       23174 :             bndend = FFMIN(end, ff_ac3_rematrix_band_tab[bnd + 1]);
     672      633686 :             for (i = ff_ac3_rematrix_band_tab[bnd]; i < bndend; i++) {
     673      610512 :                 int tmp0 = s->fixed_coeffs[1][i];
     674      610512 :                 s->fixed_coeffs[1][i] += s->fixed_coeffs[2][i];
     675      610512 :                 s->fixed_coeffs[2][i]  = tmp0 - s->fixed_coeffs[2][i];
     676             :             }
     677             :         }
     678             :     }
     679        8544 : }
     680             : 
     681             : /**
     682             :  * Inverse MDCT Transform.
     683             :  * Convert frequency domain coefficients to time-domain audio samples.
     684             :  * reference: Section 7.9.4 Transformation Equations
     685             :  */
     686       12115 : static inline void do_imdct(AC3DecodeContext *s, int channels)
     687             : {
     688             :     int ch;
     689             : 
     690       38541 :     for (ch = 1; ch <= channels; ch++) {
     691       26426 :         if (s->block_switch[ch]) {
     692             :             int i;
     693           6 :             FFTSample *x = s->tmp_output + 128;
     694         774 :             for (i = 0; i < 128; i++)
     695         768 :                 x[i] = s->transform_coeffs[ch][2 * i];
     696           6 :             s->imdct_256.imdct_half(&s->imdct_256, s->tmp_output, x);
     697             : #if USE_FIXED
     698           4 :             s->fdsp->vector_fmul_window_scaled(s->outptr[ch - 1], s->delay[ch - 1],
     699           2 :                                        s->tmp_output, s->window, 128, 8);
     700             : #else
     701           8 :             s->fdsp->vector_fmul_window(s->outptr[ch - 1], s->delay[ch - 1],
     702           4 :                                        s->tmp_output, s->window, 128);
     703             : #endif
     704         774 :             for (i = 0; i < 128; i++)
     705         768 :                 x[i] = s->transform_coeffs[ch][2 * i + 1];
     706           6 :             s->imdct_256.imdct_half(&s->imdct_256, s->delay[ch - 1], x);
     707             :         } else {
     708       26420 :             s->imdct_512.imdct_half(&s->imdct_512, s->tmp_output, s->transform_coeffs[ch]);
     709             : #if USE_FIXED
     710        5846 :             s->fdsp->vector_fmul_window_scaled(s->outptr[ch - 1], s->delay[ch - 1],
     711        2923 :                                        s->tmp_output, s->window, 128, 8);
     712             : #else
     713       46994 :             s->fdsp->vector_fmul_window(s->outptr[ch - 1], s->delay[ch - 1],
     714       23497 :                                        s->tmp_output, s->window, 128);
     715             : #endif
     716       26420 :             memcpy(s->delay[ch - 1], s->tmp_output + 128, 128 * sizeof(FFTSample));
     717             :         }
     718             :     }
     719       12115 : }
     720             : 
     721             : /**
     722             :  * Upmix delay samples from stereo to original channel layout.
     723             :  */
     724           6 : static void ac3_upmix_delay(AC3DecodeContext *s)
     725             : {
     726           6 :     int channel_data_size = sizeof(s->delay[0]);
     727           6 :     switch (s->channel_mode) {
     728           2 :     case AC3_CHMODE_DUALMONO:
     729             :     case AC3_CHMODE_STEREO:
     730             :         /* upmix mono to stereo */
     731           2 :         memcpy(s->delay[1], s->delay[0], channel_data_size);
     732           2 :         break;
     733           0 :     case AC3_CHMODE_2F2R:
     734           0 :         memset(s->delay[3], 0, channel_data_size);
     735           0 :     case AC3_CHMODE_2F1R:
     736           0 :         memset(s->delay[2], 0, channel_data_size);
     737           0 :         break;
     738           0 :     case AC3_CHMODE_3F2R:
     739           0 :         memset(s->delay[4], 0, channel_data_size);
     740           4 :     case AC3_CHMODE_3F1R:
     741           4 :         memset(s->delay[3], 0, channel_data_size);
     742           4 :     case AC3_CHMODE_3F:
     743           4 :         memcpy(s->delay[2], s->delay[1], channel_data_size);
     744           4 :         memset(s->delay[1], 0, channel_data_size);
     745           4 :         break;
     746             :     }
     747           6 : }
     748             : 
     749             : /**
     750             :  * Decode band structure for coupling, spectral extension, or enhanced coupling.
     751             :  * The band structure defines how many subbands are in each band.  For each
     752             :  * subband in the range, 1 means it is combined with the previous band, and 0
     753             :  * means that it starts a new band.
     754             :  *
     755             :  * @param[in] gbc bit reader context
     756             :  * @param[in] blk block number
     757             :  * @param[in] eac3 flag to indicate E-AC-3
     758             :  * @param[in] ecpl flag to indicate enhanced coupling
     759             :  * @param[in] start_subband subband number for start of range
     760             :  * @param[in] end_subband subband number for end of range
     761             :  * @param[in] default_band_struct default band structure table
     762             :  * @param[out] num_bands number of bands (optionally NULL)
     763             :  * @param[out] band_sizes array containing the number of bins in each band (optionally NULL)
     764             :  * @param[in,out] band_struct current band structure
     765             :  */
     766        1751 : static void decode_band_structure(GetBitContext *gbc, int blk, int eac3,
     767             :                                   int ecpl, int start_subband, int end_subband,
     768             :                                   const uint8_t *default_band_struct,
     769             :                                   int *num_bands, uint8_t *band_sizes,
     770             :                                   uint8_t *band_struct, int band_struct_size)
     771             : {
     772        1751 :     int subbnd, bnd, n_subbands, n_bands=0;
     773             :     uint8_t bnd_sz[22];
     774             : 
     775        1751 :     n_subbands = end_subband - start_subband;
     776             : 
     777        1751 :     if (!blk)
     778        1751 :         memcpy(band_struct, default_band_struct, band_struct_size);
     779             : 
     780        1751 :     av_assert0(band_struct_size >= start_subband + n_subbands);
     781             : 
     782        1751 :     band_struct += start_subband + 1;
     783             : 
     784             :     /* decode band structure from bitstream or use default */
     785        1751 :     if (!eac3 || get_bits1(gbc)) {
     786        6363 :         for (subbnd = 0; subbnd < n_subbands - 1; subbnd++) {
     787        5015 :             band_struct[subbnd] = get_bits1(gbc);
     788             :         }
     789             :     }
     790             : 
     791             :     /* calculate number of bands and band sizes based on band structure.
     792             :        note that the first 4 subbands in enhanced coupling span only 6 bins
     793             :        instead of 12. */
     794        1751 :     if (num_bands || band_sizes ) {
     795        1751 :         n_bands = n_subbands;
     796        1751 :         bnd_sz[0] = ecpl ? 6 : 12;
     797        8898 :         for (bnd = 0, subbnd = 1; subbnd < n_subbands; subbnd++) {
     798        7147 :             int subbnd_size = (ecpl && subbnd < 4) ? 6 : 12;
     799        7147 :             if (band_struct[subbnd - 1]) {
     800        3383 :                 n_bands--;
     801        3383 :                 bnd_sz[bnd] += subbnd_size;
     802             :             } else {
     803        3764 :                 bnd_sz[++bnd] = subbnd_size;
     804             :             }
     805             :         }
     806             :     }
     807             : 
     808             :     /* set optional output params */
     809        1751 :     if (num_bands)
     810        1751 :         *num_bands = n_bands;
     811        1751 :     if (band_sizes)
     812        1751 :         memcpy(band_sizes, bnd_sz, n_bands);
     813        1751 : }
     814             : 
     815         535 : static inline int spx_strategy(AC3DecodeContext *s, int blk)
     816             : {
     817         535 :     GetBitContext *bc = &s->gbc;
     818         535 :     int fbw_channels = s->fbw_channels;
     819             :     int dst_start_freq, dst_end_freq, src_start_freq,
     820             :         start_subband, end_subband, ch;
     821             : 
     822             :     /* determine which channels use spx */
     823         535 :     if (s->channel_mode == AC3_CHMODE_MONO) {
     824           0 :         s->channel_uses_spx[1] = 1;
     825             :     } else {
     826        1746 :         for (ch = 1; ch <= fbw_channels; ch++)
     827        1211 :             s->channel_uses_spx[ch] = get_bits1(bc);
     828             :     }
     829             : 
     830             :     /* get the frequency bins of the spx copy region and the spx start
     831             :        and end subbands */
     832         535 :     dst_start_freq = get_bits(bc, 2);
     833         535 :     start_subband  = get_bits(bc, 3) + 2;
     834         535 :     if (start_subband > 7)
     835         488 :         start_subband += start_subband - 7;
     836         535 :     end_subband    = get_bits(bc, 3) + 5;
     837             : #if USE_FIXED
     838           0 :     s->spx_dst_end_freq = end_freq_inv_tab[end_subband-5];
     839             : #endif
     840         535 :     if (end_subband   > 7)
     841         535 :         end_subband   += end_subband   - 7;
     842         535 :     dst_start_freq = dst_start_freq * 12 + 25;
     843         535 :     src_start_freq = start_subband  * 12 + 25;
     844         535 :     dst_end_freq   = end_subband    * 12 + 25;
     845             : 
     846             :     /* check validity of spx ranges */
     847         535 :     if (start_subband >= end_subband) {
     848           0 :         av_log(s->avctx, AV_LOG_ERROR, "invalid spectral extension "
     849             :                "range (%d >= %d)\n", start_subband, end_subband);
     850           0 :         return AVERROR_INVALIDDATA;
     851             :     }
     852         535 :     if (dst_start_freq >= src_start_freq) {
     853           0 :         av_log(s->avctx, AV_LOG_ERROR, "invalid spectral extension "
     854             :                "copy start bin (%d >= %d)\n", dst_start_freq, src_start_freq);
     855           0 :         return AVERROR_INVALIDDATA;
     856             :     }
     857             : 
     858         535 :     s->spx_dst_start_freq = dst_start_freq;
     859         535 :     s->spx_src_start_freq = src_start_freq;
     860             :     if (!USE_FIXED)
     861         535 :         s->spx_dst_end_freq   = dst_end_freq;
     862             : 
     863         535 :     decode_band_structure(bc, blk, s->eac3, 0,
     864             :                           start_subband, end_subband,
     865             :                           ff_eac3_default_spx_band_struct,
     866             :                           &s->num_spx_bands,
     867         535 :                           s->spx_band_sizes,
     868         535 :                           s->spx_band_struct, sizeof(s->spx_band_struct));
     869         535 :     return 0;
     870             : }
     871             : 
     872        3210 : static inline void spx_coordinates(AC3DecodeContext *s)
     873             : {
     874        3210 :     GetBitContext *bc = &s->gbc;
     875        3210 :     int fbw_channels = s->fbw_channels;
     876             :     int ch, bnd;
     877             : 
     878       10476 :     for (ch = 1; ch <= fbw_channels; ch++) {
     879        7266 :         if (s->channel_uses_spx[ch]) {
     880        7266 :             if (s->first_spx_coords[ch] || get_bits1(bc)) {
     881             :                 INTFLOAT spx_blend;
     882             :                 int bin, master_spx_coord;
     883             : 
     884        1950 :                 s->first_spx_coords[ch] = 0;
     885        1950 :                 spx_blend = AC3_SPX_BLEND(get_bits(bc, 5));
     886        1950 :                 master_spx_coord = get_bits(bc, 2) * 3;
     887             : 
     888        1950 :                 bin = s->spx_src_start_freq;
     889        6834 :                 for (bnd = 0; bnd < s->num_spx_bands; bnd++) {
     890        4884 :                     int bandsize = s->spx_band_sizes[bnd];
     891             :                     int spx_coord_exp, spx_coord_mant;
     892             :                     INTFLOAT nratio, sblend, nblend;
     893             : #if USE_FIXED
     894             :                     /* calculate blending factors */
     895           0 :                     int64_t accu = ((bin << 23) + (bandsize << 22))
     896           0 :                                  * (int64_t)s->spx_dst_end_freq;
     897           0 :                     nratio = (int)(accu >> 32);
     898           0 :                     nratio -= spx_blend << 18;
     899             : 
     900           0 :                     if (nratio < 0) {
     901           0 :                         nblend = 0;
     902           0 :                         sblend = 0x800000;
     903           0 :                     } else if (nratio > 0x7fffff) {
     904           0 :                         nblend = 14529495; // sqrt(3) in FP.23
     905           0 :                         sblend = 0;
     906             :                     } else {
     907           0 :                         nblend = fixed_sqrt(nratio, 23);
     908           0 :                         accu = (int64_t)nblend * 1859775393;
     909           0 :                         nblend = (int)((accu + (1<<29)) >> 30);
     910           0 :                         sblend = fixed_sqrt(0x800000 - nratio, 23);
     911             :                     }
     912             : #else
     913             :                     float spx_coord;
     914             : 
     915             :                     /* calculate blending factors */
     916        4884 :                     nratio = ((float)((bin + (bandsize >> 1))) / s->spx_dst_end_freq) - spx_blend;
     917        4884 :                     nratio = av_clipf(nratio, 0.0f, 1.0f);
     918        4884 :                     nblend = sqrtf(3.0f * nratio); // noise is scaled by sqrt(3)
     919             :                                                    // to give unity variance
     920        4884 :                     sblend = sqrtf(1.0f - nratio);
     921             : #endif
     922        4884 :                     bin += bandsize;
     923             : 
     924             :                     /* decode spx coordinates */
     925        4884 :                     spx_coord_exp  = get_bits(bc, 4);
     926        4884 :                     spx_coord_mant = get_bits(bc, 2);
     927        4884 :                     if (spx_coord_exp == 15) spx_coord_mant <<= 1;
     928        4178 :                     else                     spx_coord_mant += 4;
     929        4884 :                     spx_coord_mant <<= (25 - spx_coord_exp - master_spx_coord);
     930             : 
     931             :                     /* multiply noise and signal blending factors by spx coordinate */
     932             : #if USE_FIXED
     933           0 :                     accu = (int64_t)nblend * spx_coord_mant;
     934           0 :                     s->spx_noise_blend[ch][bnd]  = (int)((accu + (1<<22)) >> 23);
     935           0 :                     accu = (int64_t)sblend * spx_coord_mant;
     936           0 :                     s->spx_signal_blend[ch][bnd] = (int)((accu + (1<<22)) >> 23);
     937             : #else
     938        4884 :                     spx_coord = spx_coord_mant * (1.0f / (1 << 23));
     939        4884 :                     s->spx_noise_blend [ch][bnd] = nblend * spx_coord;
     940        4884 :                     s->spx_signal_blend[ch][bnd] = sblend * spx_coord;
     941             : #endif
     942             :                 }
     943             :             }
     944             :         } else {
     945           0 :             s->first_spx_coords[ch] = 1;
     946             :         }
     947             :     }
     948        3210 : }
     949             : 
     950        2102 : static inline int coupling_strategy(AC3DecodeContext *s, int blk,
     951             :                                     uint8_t *bit_alloc_stages)
     952             : {
     953        2102 :     GetBitContext *bc = &s->gbc;
     954        2102 :     int fbw_channels = s->fbw_channels;
     955        2102 :     int channel_mode = s->channel_mode;
     956             :     int ch;
     957             : 
     958        2102 :     memset(bit_alloc_stages, 3, AC3_MAX_CHANNELS);
     959        2102 :     if (!s->eac3)
     960        1067 :         s->cpl_in_use[blk] = get_bits1(bc);
     961        2102 :     if (s->cpl_in_use[blk]) {
     962             :         /* coupling in use */
     963             :         int cpl_start_subband, cpl_end_subband;
     964             : 
     965        1216 :         if (channel_mode < AC3_CHMODE_STEREO) {
     966           0 :             av_log(s->avctx, AV_LOG_ERROR, "coupling not allowed in mono or dual-mono\n");
     967           0 :             return AVERROR_INVALIDDATA;
     968             :         }
     969             : 
     970             :         /* check for enhanced coupling */
     971        1216 :         if (s->eac3 && get_bits1(bc)) {
     972             :             /* TODO: parse enhanced coupling strategy info */
     973           0 :             avpriv_request_sample(s->avctx, "Enhanced coupling");
     974           0 :             return AVERROR_PATCHWELCOME;
     975             :         }
     976             : 
     977             :         /* determine which channels are coupled */
     978        1216 :         if (s->eac3 && s->channel_mode == AC3_CHMODE_STEREO) {
     979         403 :             s->channel_in_cpl[1] = 1;
     980         403 :             s->channel_in_cpl[2] = 1;
     981             :         } else {
     982        3279 :             for (ch = 1; ch <= fbw_channels; ch++)
     983        2466 :                 s->channel_in_cpl[ch] = get_bits1(bc);
     984             :         }
     985             : 
     986             :         /* phase flags in use */
     987        1216 :         if (channel_mode == AC3_CHMODE_STEREO)
     988         936 :             s->phase_flags_in_use = get_bits1(bc);
     989             : 
     990             :         /* coupling frequency range */
     991        1216 :         cpl_start_subband = get_bits(bc, 4);
     992        2432 :         cpl_end_subband = s->spx_in_use ? (s->spx_src_start_freq - 37) / 12 :
     993        1216 :                                           get_bits(bc, 4) + 3;
     994        1216 :         if (cpl_start_subband >= cpl_end_subband) {
     995           0 :             av_log(s->avctx, AV_LOG_ERROR, "invalid coupling range (%d >= %d)\n",
     996             :                    cpl_start_subband, cpl_end_subband);
     997           0 :             return AVERROR_INVALIDDATA;
     998             :         }
     999        1216 :         s->start_freq[CPL_CH] = cpl_start_subband * 12 + 37;
    1000        1216 :         s->end_freq[CPL_CH]   = cpl_end_subband   * 12 + 37;
    1001             : 
    1002        1216 :         decode_band_structure(bc, blk, s->eac3, 0, cpl_start_subband,
    1003             :                               cpl_end_subband,
    1004             :                               ff_eac3_default_cpl_band_struct,
    1005        1216 :                               &s->num_cpl_bands, s->cpl_band_sizes,
    1006        1216 :                               s->cpl_band_struct, sizeof(s->cpl_band_struct));
    1007             :     } else {
    1008             :         /* coupling not in use */
    1009        3594 :         for (ch = 1; ch <= fbw_channels; ch++) {
    1010        2708 :             s->channel_in_cpl[ch] = 0;
    1011        2708 :             s->first_cpl_coords[ch] = 1;
    1012             :         }
    1013         886 :         s->first_cpl_leak = s->eac3;
    1014         886 :         s->phase_flags_in_use = 0;
    1015             :     }
    1016             : 
    1017        2102 :     return 0;
    1018             : }
    1019             : 
    1020        7292 : static inline int coupling_coordinates(AC3DecodeContext *s, int blk)
    1021             : {
    1022        7292 :     GetBitContext *bc = &s->gbc;
    1023        7292 :     int fbw_channels = s->fbw_channels;
    1024             :     int ch, bnd;
    1025        7292 :     int cpl_coords_exist = 0;
    1026             : 
    1027       26916 :     for (ch = 1; ch <= fbw_channels; ch++) {
    1028       19624 :         if (s->channel_in_cpl[ch]) {
    1029       25449 :             if ((s->eac3 && s->first_cpl_coords[ch]) || get_bits1(bc)) {
    1030             :                 int master_cpl_coord, cpl_coord_exp, cpl_coord_mant;
    1031        5825 :                 s->first_cpl_coords[ch] = 0;
    1032        5825 :                 cpl_coords_exist = 1;
    1033        5825 :                 master_cpl_coord = 3 * get_bits(bc, 2);
    1034       21275 :                 for (bnd = 0; bnd < s->num_cpl_bands; bnd++) {
    1035       15450 :                     cpl_coord_exp  = get_bits(bc, 4);
    1036       15450 :                     cpl_coord_mant = get_bits(bc, 4);
    1037       15450 :                     if (cpl_coord_exp == 15)
    1038        2570 :                         s->cpl_coords[ch][bnd] = cpl_coord_mant << 22;
    1039             :                     else
    1040       12880 :                         s->cpl_coords[ch][bnd] = (cpl_coord_mant + 16) << 21;
    1041       15450 :                     s->cpl_coords[ch][bnd] >>= (cpl_coord_exp + master_cpl_coord);
    1042             :                 }
    1043       13799 :             } else if (!blk) {
    1044           0 :                 av_log(s->avctx, AV_LOG_ERROR, "new coupling coordinates must "
    1045             :                        "be present in block 0\n");
    1046           0 :                 return AVERROR_INVALIDDATA;
    1047             :             }
    1048             :         } else {
    1049             :             /* channel not in coupling */
    1050           0 :             s->first_cpl_coords[ch] = 1;
    1051             :         }
    1052             :     }
    1053             :     /* phase flags */
    1054        7292 :     if (s->channel_mode == AC3_CHMODE_STEREO && cpl_coords_exist) {
    1055        4810 :         for (bnd = 0; bnd < s->num_cpl_bands; bnd++) {
    1056        3848 :             s->phase_flags[bnd] = s->phase_flags_in_use ? get_bits1(bc) : 0;
    1057             :         }
    1058             :     }
    1059             : 
    1060        7292 :     return 0;
    1061             : }
    1062             : 
    1063             : /**
    1064             :  * Decode a single audio block from the AC-3 bitstream.
    1065             :  */
    1066       12115 : static int decode_audio_block(AC3DecodeContext *s, int blk)
    1067             : {
    1068       12115 :     int fbw_channels = s->fbw_channels;
    1069       12115 :     int channel_mode = s->channel_mode;
    1070             :     int i, bnd, seg, ch, ret;
    1071             :     int different_transforms;
    1072             :     int downmix_output;
    1073             :     int cpl_in_use;
    1074       12115 :     GetBitContext *gbc = &s->gbc;
    1075       12115 :     uint8_t bit_alloc_stages[AC3_MAX_CHANNELS] = { 0 };
    1076             : 
    1077             :     /* block switch flags */
    1078       12115 :     different_transforms = 0;
    1079       12115 :     if (s->block_switch_syntax) {
    1080       27234 :         for (ch = 1; ch <= fbw_channels; ch++) {
    1081       20844 :             s->block_switch[ch] = get_bits1(gbc);
    1082       20844 :             if (ch > 1 && s->block_switch[ch] != s->block_switch[1])
    1083           6 :                 different_transforms = 1;
    1084             :         }
    1085             :     }
    1086             : 
    1087             :     /* dithering flags */
    1088       12115 :     if (s->dither_flag_syntax) {
    1089       27234 :         for (ch = 1; ch <= fbw_channels; ch++) {
    1090       20844 :             s->dither_flag[ch] = get_bits1(gbc);
    1091             :         }
    1092             :     }
    1093             : 
    1094             :     /* dynamic range */
    1095       12115 :     i = !s->channel_mode;
    1096             :     do {
    1097       12115 :         if (get_bits1(gbc)) {
    1098             :             /* Allow asymmetric application of DRC when drc_scale > 1.
    1099             :                Amplification of quiet sounds is enhanced */
    1100        1584 :             int range_bits = get_bits(gbc, 8);
    1101        1584 :             INTFLOAT range = AC3_RANGE(range_bits);
    1102        1584 :             if (range_bits <= 127 || s->drc_scale <= 1.0)
    1103        1486 :                 s->dynamic_range[i] = AC3_DYNAMIC_RANGE(range);
    1104             :             else
    1105          98 :                 s->dynamic_range[i] = range;
    1106       10531 :         } else if (blk == 0) {
    1107         700 :             s->dynamic_range[i] = AC3_DYNAMIC_RANGE1;
    1108             :         }
    1109       12115 :     } while (i--);
    1110             : 
    1111             :     /* spectral extension strategy */
    1112       12115 :     if (s->eac3 && (!blk || get_bits1(gbc))) {
    1113        1035 :         s->spx_in_use = get_bits1(gbc);
    1114        1035 :         if (s->spx_in_use) {
    1115         535 :             if ((ret = spx_strategy(s, blk)) < 0)
    1116           0 :                 return ret;
    1117             :         }
    1118             :     }
    1119       12115 :     if (!s->eac3 || !s->spx_in_use) {
    1120        8905 :         s->spx_in_use = 0;
    1121       35070 :         for (ch = 1; ch <= fbw_channels; ch++) {
    1122       26165 :             s->channel_uses_spx[ch] = 0;
    1123       26165 :             s->first_spx_coords[ch] = 1;
    1124             :         }
    1125             :     }
    1126             : 
    1127             :     /* spectral extension coordinates */
    1128       12115 :     if (s->spx_in_use)
    1129        3210 :         spx_coordinates(s);
    1130             : 
    1131             :     /* coupling strategy */
    1132       12115 :     if (s->eac3 ? s->cpl_strategy_exists[blk] : get_bits1(gbc)) {
    1133        2102 :         if ((ret = coupling_strategy(s, blk, bit_alloc_stages)) < 0)
    1134           0 :             return ret;
    1135       10013 :     } else if (!s->eac3) {
    1136        5323 :         if (!blk) {
    1137           0 :             av_log(s->avctx, AV_LOG_ERROR, "new coupling strategy must "
    1138             :                    "be present in block 0\n");
    1139           0 :             return AVERROR_INVALIDDATA;
    1140             :         } else {
    1141        5323 :             s->cpl_in_use[blk] = s->cpl_in_use[blk-1];
    1142             :         }
    1143             :     }
    1144       12115 :     cpl_in_use = s->cpl_in_use[blk];
    1145             : 
    1146             :     /* coupling coordinates */
    1147       12115 :     if (cpl_in_use) {
    1148        7292 :         if ((ret = coupling_coordinates(s, blk)) < 0)
    1149           0 :             return ret;
    1150             :     }
    1151             : 
    1152             :     /* stereo rematrixing strategy and band structure */
    1153       12115 :     if (channel_mode == AC3_CHMODE_STEREO) {
    1154       11376 :         if ((s->eac3 && !blk) || get_bits1(gbc)) {
    1155        2832 :             s->num_rematrixing_bands = 4;
    1156        2832 :             if (cpl_in_use && s->start_freq[CPL_CH] <= 61) {
    1157           0 :                 s->num_rematrixing_bands -= 1 + (s->start_freq[CPL_CH] == 37);
    1158        2832 :             } else if (s->spx_in_use && s->spx_src_start_freq <= 61) {
    1159           0 :                 s->num_rematrixing_bands--;
    1160             :             }
    1161       14160 :             for (bnd = 0; bnd < s->num_rematrixing_bands; bnd++)
    1162       11328 :                 s->rematrixing_flags[bnd] = get_bits1(gbc);
    1163        5712 :         } else if (!blk) {
    1164           0 :             av_log(s->avctx, AV_LOG_WARNING, "Warning: "
    1165             :                    "new rematrixing strategy not present in block 0\n");
    1166           0 :             s->num_rematrixing_bands = 0;
    1167             :         }
    1168             :     }
    1169             : 
    1170             :     /* exponent strategies for each channel */
    1171       54897 :     for (ch = !cpl_in_use; ch <= s->channels; ch++) {
    1172       42782 :         if (!s->eac3)
    1173       27398 :             s->exp_strategy[blk][ch] = get_bits(gbc, 2 - (ch == s->lfe_ch));
    1174       42782 :         if (s->exp_strategy[blk][ch] != EXP_REUSE)
    1175       11072 :             bit_alloc_stages[ch] = 3;
    1176             :     }
    1177             : 
    1178             :     /* channel bandwidth */
    1179       45546 :     for (ch = 1; ch <= fbw_channels; ch++) {
    1180       33431 :         s->start_freq[ch] = 0;
    1181       33431 :         if (s->exp_strategy[blk][ch] != EXP_REUSE) {
    1182             :             int group_size;
    1183        8233 :             int prev = s->end_freq[ch];
    1184        8233 :             if (s->channel_in_cpl[ch])
    1185        4098 :                 s->end_freq[ch] = s->start_freq[CPL_CH];
    1186        4135 :             else if (s->channel_uses_spx[ch])
    1187        1950 :                 s->end_freq[ch] = s->spx_src_start_freq;
    1188             :             else {
    1189        2185 :                 int bandwidth_code = get_bits(gbc, 6);
    1190        2185 :                 if (bandwidth_code > 60) {
    1191           0 :                     av_log(s->avctx, AV_LOG_ERROR, "bandwidth code = %d > 60\n", bandwidth_code);
    1192           0 :                     return AVERROR_INVALIDDATA;
    1193             :                 }
    1194        2185 :                 s->end_freq[ch] = bandwidth_code * 3 + 73;
    1195             :             }
    1196        8233 :             group_size = 3 << (s->exp_strategy[blk][ch] - 1);
    1197        8233 :             s->num_exp_groups[ch] = (s->end_freq[ch] + group_size-4) / group_size;
    1198        8233 :             if (blk > 0 && s->end_freq[ch] != prev)
    1199           4 :                 memset(bit_alloc_stages, 3, AC3_MAX_CHANNELS);
    1200             :         }
    1201             :     }
    1202       12115 :     if (cpl_in_use && s->exp_strategy[blk][CPL_CH] != EXP_REUSE) {
    1203        4790 :         s->num_exp_groups[CPL_CH] = (s->end_freq[CPL_CH] - s->start_freq[CPL_CH]) /
    1204        2395 :                                     (3 << (s->exp_strategy[blk][CPL_CH] - 1));
    1205             :     }
    1206             : 
    1207             :     /* decode exponents for each channel */
    1208       54897 :     for (ch = !cpl_in_use; ch <= s->channels; ch++) {
    1209       42782 :         if (s->exp_strategy[blk][ch] != EXP_REUSE) {
    1210       11072 :             s->dexps[ch][0] = get_bits(gbc, 4) << !ch;
    1211       22144 :             if (decode_exponents(s, gbc, s->exp_strategy[blk][ch],
    1212       11072 :                                  s->num_exp_groups[ch], s->dexps[ch][0],
    1213       11072 :                                  &s->dexps[ch][s->start_freq[ch]+!!ch])) {
    1214           0 :                 return AVERROR_INVALIDDATA;
    1215             :             }
    1216       11072 :             if (ch != CPL_CH && ch != s->lfe_ch)
    1217        8233 :                 skip_bits(gbc, 2); /* skip gainrng */
    1218             :         }
    1219             :     }
    1220             : 
    1221             :     /* bit allocation information */
    1222       12115 :     if (s->bit_allocation_syntax) {
    1223        7255 :         if (get_bits1(gbc)) {
    1224        1317 :             s->bit_alloc_params.slow_decay = ff_ac3_slow_decay_tab[get_bits(gbc, 2)] >> s->bit_alloc_params.sr_shift;
    1225        1317 :             s->bit_alloc_params.fast_decay = ff_ac3_fast_decay_tab[get_bits(gbc, 2)] >> s->bit_alloc_params.sr_shift;
    1226        1317 :             s->bit_alloc_params.slow_gain  = ff_ac3_slow_gain_tab[get_bits(gbc, 2)];
    1227        1317 :             s->bit_alloc_params.db_per_bit = ff_ac3_db_per_bit_tab[get_bits(gbc, 2)];
    1228        1317 :             s->bit_alloc_params.floor  = ff_ac3_floor_tab[get_bits(gbc, 3)];
    1229        7022 :             for (ch = !cpl_in_use; ch <= s->channels; ch++)
    1230        5705 :                 bit_alloc_stages[ch] = FFMAX(bit_alloc_stages[ch], 2);
    1231        5938 :         } else if (!blk) {
    1232           0 :             av_log(s->avctx, AV_LOG_ERROR, "new bit allocation info must "
    1233             :                    "be present in block 0\n");
    1234           0 :             return AVERROR_INVALIDDATA;
    1235             :         }
    1236             :     }
    1237             : 
    1238             :     /* signal-to-noise ratio offsets and fast gains (signal-to-mask ratios) */
    1239       12115 :     if (!s->eac3 || !blk) {
    1240        8490 :         if (s->snr_offset_strategy && get_bits1(gbc)) {
    1241        1065 :             int snr = 0;
    1242             :             int csnr;
    1243        1065 :             csnr = (get_bits(gbc, 6) - 15) << 4;
    1244        5632 :             for (i = ch = !cpl_in_use; ch <= s->channels; ch++) {
    1245             :                 /* snr offset */
    1246        4567 :                 if (ch == i || s->snr_offset_strategy == 2)
    1247        4567 :                     snr = (csnr + get_bits(gbc, 4)) << 2;
    1248             :                 /* run at least last bit allocation stage if snr offset changes */
    1249        4567 :                 if (blk && s->snr_offset[ch] != snr) {
    1250           0 :                     bit_alloc_stages[ch] = FFMAX(bit_alloc_stages[ch], 1);
    1251             :                 }
    1252        4567 :                 s->snr_offset[ch] = snr;
    1253             : 
    1254             :                 /* fast gain (normal AC-3 only) */
    1255        4567 :                 if (!s->eac3) {
    1256        4567 :                     int prev = s->fast_gain[ch];
    1257        4567 :                     s->fast_gain[ch] = ff_ac3_fast_gain_tab[get_bits(gbc, 3)];
    1258             :                     /* run last 2 bit allocation stages if fast gain changes */
    1259        4567 :                     if (blk && prev != s->fast_gain[ch])
    1260           0 :                         bit_alloc_stages[ch] = FFMAX(bit_alloc_stages[ch], 2);
    1261             :                 }
    1262             :             }
    1263        6360 :         } else if (!s->eac3 && !blk) {
    1264           0 :             av_log(s->avctx, AV_LOG_ERROR, "new snr offsets must be present in block 0\n");
    1265           0 :             return AVERROR_INVALIDDATA;
    1266             :         }
    1267             :     }
    1268             : 
    1269             :     /* fast gain (E-AC-3 only) */
    1270       12115 :     if (s->fast_gain_syntax && get_bits1(gbc)) {
    1271           0 :         for (ch = !cpl_in_use; ch <= s->channels; ch++) {
    1272           0 :             int prev = s->fast_gain[ch];
    1273           0 :             s->fast_gain[ch] = ff_ac3_fast_gain_tab[get_bits(gbc, 3)];
    1274             :             /* run last 2 bit allocation stages if fast gain changes */
    1275           0 :             if (blk && prev != s->fast_gain[ch])
    1276           0 :                 bit_alloc_stages[ch] = FFMAX(bit_alloc_stages[ch], 2);
    1277             :         }
    1278       12115 :     } else if (s->eac3 && !blk) {
    1279        4084 :         for (ch = !cpl_in_use; ch <= s->channels; ch++)
    1280        3049 :             s->fast_gain[ch] = ff_ac3_fast_gain_tab[4];
    1281             :     }
    1282             : 
    1283             :     /* E-AC-3 to AC-3 converter SNR offset */
    1284       12115 :     if (s->frame_type == EAC3_FRAME_TYPE_INDEPENDENT && get_bits1(gbc)) {
    1285         681 :         skip_bits(gbc, 10); // skip converter snr offset
    1286             :     }
    1287             : 
    1288             :     /* coupling leak information */
    1289       12115 :     if (cpl_in_use) {
    1290        8554 :         if (s->first_cpl_leak || get_bits1(gbc)) {
    1291        1262 :             int fl = get_bits(gbc, 3);
    1292        1262 :             int sl = get_bits(gbc, 3);
    1293             :             /* run last 2 bit allocation stages for coupling channel if
    1294             :                coupling leak changes */
    1295        1263 :             if (blk && (fl != s->bit_alloc_params.cpl_fast_leak ||
    1296           1 :                 sl != s->bit_alloc_params.cpl_slow_leak)) {
    1297          46 :                 bit_alloc_stages[CPL_CH] = FFMAX(bit_alloc_stages[CPL_CH], 2);
    1298             :             }
    1299        1262 :             s->bit_alloc_params.cpl_fast_leak = fl;
    1300        1262 :             s->bit_alloc_params.cpl_slow_leak = sl;
    1301        6030 :         } else if (!s->eac3 && !blk) {
    1302           0 :             av_log(s->avctx, AV_LOG_ERROR, "new coupling leak info must "
    1303             :                    "be present in block 0\n");
    1304           0 :             return AVERROR_INVALIDDATA;
    1305             :         }
    1306        7292 :         s->first_cpl_leak = 0;
    1307             :     }
    1308             : 
    1309             :     /* delta bit allocation information */
    1310       12115 :     if (s->dba_syntax && get_bits1(gbc)) {
    1311             :         /* delta bit allocation exists (strategy) */
    1312           0 :         for (ch = !cpl_in_use; ch <= fbw_channels; ch++) {
    1313           0 :             s->dba_mode[ch] = get_bits(gbc, 2);
    1314           0 :             if (s->dba_mode[ch] == DBA_RESERVED) {
    1315           0 :                 av_log(s->avctx, AV_LOG_ERROR, "delta bit allocation strategy reserved\n");
    1316           0 :                 return AVERROR_INVALIDDATA;
    1317             :             }
    1318           0 :             bit_alloc_stages[ch] = FFMAX(bit_alloc_stages[ch], 2);
    1319             :         }
    1320             :         /* channel delta offset, len and bit allocation */
    1321           0 :         for (ch = !cpl_in_use; ch <= fbw_channels; ch++) {
    1322           0 :             if (s->dba_mode[ch] == DBA_NEW) {
    1323           0 :                 s->dba_nsegs[ch] = get_bits(gbc, 3) + 1;
    1324           0 :                 for (seg = 0; seg < s->dba_nsegs[ch]; seg++) {
    1325           0 :                     s->dba_offsets[ch][seg] = get_bits(gbc, 5);
    1326           0 :                     s->dba_lengths[ch][seg] = get_bits(gbc, 4);
    1327           0 :                     s->dba_values[ch][seg]  = get_bits(gbc, 3);
    1328             :                 }
    1329             :                 /* run last 2 bit allocation stages if new dba values */
    1330           0 :                 bit_alloc_stages[ch] = FFMAX(bit_alloc_stages[ch], 2);
    1331             :             }
    1332             :         }
    1333       12115 :     } else if (blk == 0) {
    1334       10600 :         for (ch = 0; ch <= s->channels; ch++) {
    1335        8500 :             s->dba_mode[ch] = DBA_NONE;
    1336             :         }
    1337             :     }
    1338             : 
    1339             :     /* Bit allocation */
    1340       54897 :     for (ch = !cpl_in_use; ch <= s->channels; ch++) {
    1341       42782 :         if (bit_alloc_stages[ch] > 2) {
    1342             :             /* Exponent mapping into PSD and PSD integration */
    1343       11072 :             ff_ac3_bit_alloc_calc_psd(s->dexps[ch],
    1344             :                                       s->start_freq[ch], s->end_freq[ch],
    1345       11072 :                                       s->psd[ch], s->band_psd[ch]);
    1346             :         }
    1347       42782 :         if (bit_alloc_stages[ch] > 1) {
    1348             :             /* Compute excitation function, Compute masking curve, and
    1349             :                Apply delta bit allocation */
    1350       22348 :             if (ff_ac3_bit_alloc_calc_mask(&s->bit_alloc_params, s->band_psd[ch],
    1351             :                                            s->start_freq[ch],  s->end_freq[ch],
    1352       11174 :                                            s->fast_gain[ch],   (ch == s->lfe_ch),
    1353             :                                            s->dba_mode[ch],    s->dba_nsegs[ch],
    1354       11174 :                                            s->dba_offsets[ch], s->dba_lengths[ch],
    1355       11174 :                                            s->dba_values[ch],  s->mask[ch])) {
    1356           0 :                 av_log(s->avctx, AV_LOG_ERROR, "error in bit allocation\n");
    1357           0 :                 return AVERROR_INVALIDDATA;
    1358             :             }
    1359             :         }
    1360       42782 :         if (bit_alloc_stages[ch] > 0) {
    1361             :             /* Compute bit allocation */
    1362       22348 :             const uint8_t *bap_tab = s->channel_uses_aht[ch] ?
    1363       11174 :                                      ff_eac3_hebap_tab : ff_ac3_bap_tab;
    1364       22348 :             s->ac3dsp.bit_alloc_calc_bap(s->mask[ch], s->psd[ch],
    1365             :                                       s->start_freq[ch], s->end_freq[ch],
    1366             :                                       s->snr_offset[ch],
    1367             :                                       s->bit_alloc_params.floor,
    1368       11174 :                                       bap_tab, s->bap[ch]);
    1369             :         }
    1370             :     }
    1371             : 
    1372             :     /* unused dummy data */
    1373       12115 :     if (s->skip_syntax && get_bits1(gbc)) {
    1374         898 :         int skipl = get_bits(gbc, 9);
    1375         898 :         skip_bits_long(gbc, 8 * skipl);
    1376             :     }
    1377             : 
    1378             :     /* unpack the transform coefficients
    1379             :        this also uncouples channels if coupling is in use. */
    1380       12115 :     decode_transform_coeffs(s, blk);
    1381             : 
    1382             :     /* TODO: generate enhanced coupling coordinates and uncouple */
    1383             : 
    1384             :     /* recover coefficients if rematrixing is in use */
    1385       12115 :     if (s->channel_mode == AC3_CHMODE_STEREO)
    1386        8544 :         do_rematrixing(s);
    1387             : 
    1388             :     /* apply scaling to coefficients (headroom, dynrng) */
    1389       47605 :     for (ch = 1; ch <= s->channels; ch++) {
    1390       35490 :         int audio_channel = 0;
    1391             :         INTFLOAT gain;
    1392       35490 :         if (s->channel_mode == AC3_CHMODE_DUALMONO && ch <= 2)
    1393           0 :             audio_channel = 2-ch;
    1394       35490 :         if (s->heavy_compression && s->compression_exists[audio_channel])
    1395           0 :             gain = s->heavy_dynamic_range[audio_channel];
    1396             :         else
    1397       35490 :             gain = s->dynamic_range[audio_channel];
    1398             : 
    1399             : #if USE_FIXED
    1400        7008 :         scale_coefs(s->transform_coeffs[ch], s->fixed_coeffs[ch], gain, 256);
    1401             : #else
    1402       28482 :         if (s->target_level != 0)
    1403           0 :           gain = gain * s->level_gain[audio_channel];
    1404       28482 :         gain *= 1.0 / 4194304.0f;
    1405       56964 :         s->fmt_conv.int32_to_float_fmul_scalar(s->transform_coeffs[ch],
    1406       28482 :                                                s->fixed_coeffs[ch], gain, 256);
    1407             : #endif
    1408             :     }
    1409             : 
    1410             :     /* apply spectral extension to high frequency bins */
    1411       12115 :     if (CONFIG_EAC3_DECODER && s->spx_in_use) {
    1412        3210 :         ff_eac3_apply_spectral_extension(s);
    1413             :     }
    1414             : 
    1415             :     /* downmix and MDCT. order depends on whether block switching is used for
    1416             :        any channel in this block. this is because coefficients for the long
    1417             :        and short transforms cannot be mixed. */
    1418       17071 :     downmix_output = s->channels != s->out_channels &&
    1419        2478 :                      !((s->output_mode & AC3_OUTPUT_LFEON) &&
    1420           0 :                      s->fbw_channels == s->out_channels);
    1421       12115 :     if (different_transforms) {
    1422             :         /* the delay samples have already been downmixed, so we upmix the delay
    1423             :            samples in order to reconstruct all channels before downmixing. */
    1424           6 :         if (s->downmixed) {
    1425           6 :             s->downmixed = 0;
    1426           6 :             ac3_upmix_delay(s);
    1427             :         }
    1428             : 
    1429           6 :         do_imdct(s, s->channels);
    1430             : 
    1431           6 :         if (downmix_output) {
    1432             : #if USE_FIXED
    1433           1 :             ac3_downmix_c_fixed16(s->outptr, s->downmix_coeffs,
    1434             :                               s->out_channels, s->fbw_channels, 256);
    1435             : #else
    1436           2 :             ff_ac3dsp_downmix(&s->ac3dsp, s->outptr, s->downmix_coeffs,
    1437             :                               s->out_channels, s->fbw_channels, 256);
    1438             : #endif
    1439             :         }
    1440             :     } else {
    1441       12109 :         if (downmix_output) {
    1442        2475 :             AC3_RENAME(ff_ac3dsp_downmix)(&s->ac3dsp, s->xcfptr + 1, s->downmix_coeffs,
    1443             :                                           s->out_channels, s->fbw_channels, 256);
    1444             :         }
    1445             : 
    1446       12109 :         if (downmix_output && !s->downmixed) {
    1447           3 :             s->downmixed = 1;
    1448           3 :             AC3_RENAME(ff_ac3dsp_downmix)(&s->ac3dsp, s->dlyptr, s->downmix_coeffs,
    1449             :                                           s->out_channels, s->fbw_channels, 128);
    1450             :         }
    1451             : 
    1452       12109 :         do_imdct(s, s->out_channels);
    1453             :     }
    1454             : 
    1455       12115 :     return 0;
    1456             : }
    1457             : 
    1458             : /**
    1459             :  * Decode a single AC-3 frame.
    1460             :  */
    1461        2107 : static int ac3_decode_frame(AVCodecContext * avctx, void *data,
    1462             :                             int *got_frame_ptr, AVPacket *avpkt)
    1463             : {
    1464        2107 :     AVFrame *frame     = data;
    1465        2107 :     const uint8_t *buf = avpkt->data;
    1466        2107 :     int buf_size = avpkt->size;
    1467        2107 :     AC3DecodeContext *s = avctx->priv_data;
    1468             :     int blk, ch, err, ret;
    1469             :     const uint8_t *channel_map;
    1470             :     const SHORTFLOAT *output[AC3_MAX_CHANNELS];
    1471             :     enum AVMatrixEncoding matrix_encoding;
    1472             :     AVDownmixInfo *downmix_info;
    1473             : 
    1474             :     /* copy input buffer to decoder context to avoid reading past the end
    1475             :        of the buffer, which can be caused by a damaged input stream. */
    1476        2107 :     if (buf_size >= 2 && AV_RB16(buf) == 0x770B) {
    1477             :         // seems to be byte-swapped AC-3
    1478           0 :         int cnt = FFMIN(buf_size, AC3_FRAME_BUFFER_SIZE) >> 1;
    1479           0 :         s->bdsp.bswap16_buf((uint16_t *) s->input_buffer,
    1480             :                             (const uint16_t *) buf, cnt);
    1481             :     } else
    1482        2107 :         memcpy(s->input_buffer, buf, FFMIN(buf_size, AC3_FRAME_BUFFER_SIZE));
    1483             : 
    1484             :     /* if consistent noise generation is enabled, seed the linear feedback generator
    1485             :      * with the contents of the AC-3 frame so that the noise is identical across
    1486             :      * decodes given the same AC-3 frame data, for use with non-linear edititing software. */
    1487        2107 :     if (s->consistent_noise_generation)
    1488           0 :         av_lfg_init_from_data(&s->dith_state, s->input_buffer, FFMIN(buf_size, AC3_FRAME_BUFFER_SIZE));
    1489             : 
    1490        2107 :     buf = s->input_buffer;
    1491             :     /* initialize the GetBitContext with the start of valid AC-3 Frame */
    1492        2107 :     if ((ret = init_get_bits8(&s->gbc, buf, buf_size)) < 0)
    1493           0 :         return ret;
    1494             : 
    1495             :     /* parse the syncinfo */
    1496        2107 :     err = parse_frame_header(s);
    1497             : 
    1498        2107 :     if (err) {
    1499           0 :         switch (err) {
    1500           0 :         case AAC_AC3_PARSE_ERROR_SYNC:
    1501           0 :             av_log(avctx, AV_LOG_ERROR, "frame sync error\n");
    1502           0 :             return AVERROR_INVALIDDATA;
    1503           0 :         case AAC_AC3_PARSE_ERROR_BSID:
    1504           0 :             av_log(avctx, AV_LOG_ERROR, "invalid bitstream id\n");
    1505           0 :             break;
    1506           0 :         case AAC_AC3_PARSE_ERROR_SAMPLE_RATE:
    1507           0 :             av_log(avctx, AV_LOG_ERROR, "invalid sample rate\n");
    1508           0 :             break;
    1509           0 :         case AAC_AC3_PARSE_ERROR_FRAME_SIZE:
    1510           0 :             av_log(avctx, AV_LOG_ERROR, "invalid frame size\n");
    1511           0 :             break;
    1512           0 :         case AAC_AC3_PARSE_ERROR_FRAME_TYPE:
    1513             :             /* skip frame if CRC is ok. otherwise use error concealment. */
    1514             :             /* TODO: add support for substreams and dependent frames */
    1515           0 :             if (s->frame_type == EAC3_FRAME_TYPE_DEPENDENT || s->substreamid) {
    1516           0 :                 av_log(avctx, AV_LOG_DEBUG,
    1517             :                        "unsupported frame type %d: skipping frame\n",
    1518             :                        s->frame_type);
    1519           0 :                 *got_frame_ptr = 0;
    1520           0 :                 return buf_size;
    1521             :             } else {
    1522           0 :                 av_log(avctx, AV_LOG_ERROR, "invalid frame type\n");
    1523             :             }
    1524           0 :             break;
    1525           0 :         case AAC_AC3_PARSE_ERROR_CRC:
    1526             :         case AAC_AC3_PARSE_ERROR_CHANNEL_CFG:
    1527           0 :             break;
    1528           0 :         default: // Normal AVERROR do not try to recover.
    1529           0 :             *got_frame_ptr = 0;
    1530           0 :             return err;
    1531             :         }
    1532             :     } else {
    1533             :         /* check that reported frame size fits in input buffer */
    1534        2107 :         if (s->frame_size > buf_size) {
    1535           7 :             av_log(avctx, AV_LOG_ERROR, "incomplete frame\n");
    1536           7 :             err = AAC_AC3_PARSE_ERROR_FRAME_SIZE;
    1537        2100 :         } else if (avctx->err_recognition & (AV_EF_CRCCHECK|AV_EF_CAREFUL)) {
    1538             :             /* check for crc mismatch */
    1539           0 :             if (av_crc(av_crc_get_table(AV_CRC_16_ANSI), 0, &buf[2],
    1540           0 :                        s->frame_size - 2)) {
    1541           0 :                 av_log(avctx, AV_LOG_ERROR, "frame CRC mismatch\n");
    1542           0 :                 if (avctx->err_recognition & AV_EF_EXPLODE)
    1543           0 :                     return AVERROR_INVALIDDATA;
    1544           0 :                 err = AAC_AC3_PARSE_ERROR_CRC;
    1545             :             }
    1546             :         }
    1547             :     }
    1548             : 
    1549             :     /* if frame is ok, set audio parameters */
    1550        2107 :     if (!err) {
    1551        2100 :         avctx->sample_rate = s->sample_rate;
    1552        2100 :         avctx->bit_rate    = s->bit_rate;
    1553             :     }
    1554             : 
    1555             :     /* channel config */
    1556        2107 :     if (!err || (s->channels && s->out_channels != s->channels)) {
    1557        2104 :         s->out_channels = s->channels;
    1558        2104 :         s->output_mode  = s->channel_mode;
    1559        2104 :         if (s->lfe_on)
    1560         428 :             s->output_mode |= AC3_OUTPUT_LFEON;
    1561        4208 :         if (s->channels > 1 &&
    1562        2104 :             avctx->request_channel_layout == AV_CH_LAYOUT_MONO) {
    1563         240 :             s->out_channels = 1;
    1564         240 :             s->output_mode  = AC3_CHMODE_MONO;
    1565        2304 :         } else if (s->channels > 2 &&
    1566         440 :                    avctx->request_channel_layout == AV_CH_LAYOUT_STEREO) {
    1567         177 :             s->out_channels = 2;
    1568         177 :             s->output_mode  = AC3_CHMODE_STEREO;
    1569             :         }
    1570             : 
    1571        2104 :         s->loro_center_mix_level   = gain_levels[s->  center_mix_level];
    1572        2104 :         s->loro_surround_mix_level = gain_levels[s->surround_mix_level];
    1573        2104 :         s->ltrt_center_mix_level   = LEVEL_MINUS_3DB;
    1574        2104 :         s->ltrt_surround_mix_level = LEVEL_MINUS_3DB;
    1575             :         /* set downmixing coefficients if needed */
    1576        4208 :         if (s->channels != s->out_channels && !((s->output_mode & AC3_OUTPUT_LFEON) &&
    1577           0 :                 s->fbw_channels == s->out_channels)) {
    1578         417 :             if ((ret = set_downmix_coeffs(s)) < 0) {
    1579           0 :                 av_log(avctx, AV_LOG_ERROR, "error setting downmix coeffs\n");
    1580           0 :                 return ret;
    1581             :             }
    1582             :         }
    1583           3 :     } else if (!s->channels) {
    1584           0 :         av_log(avctx, AV_LOG_ERROR, "unable to determine channel mode\n");
    1585           0 :         return AVERROR_INVALIDDATA;
    1586             :     }
    1587        2107 :     avctx->channels = s->out_channels;
    1588        2107 :     avctx->channel_layout = avpriv_ac3_channel_layout_tab[s->output_mode & ~AC3_OUTPUT_LFEON];
    1589        2107 :     if (s->output_mode & AC3_OUTPUT_LFEON)
    1590         201 :         avctx->channel_layout |= AV_CH_LOW_FREQUENCY;
    1591             : 
    1592             :     /* set audio service type based on bitstream mode for AC-3 */
    1593        2107 :     avctx->audio_service_type = s->bitstream_mode;
    1594        2107 :     if (s->bitstream_mode == 0x7 && s->channels > 1)
    1595           0 :         avctx->audio_service_type = AV_AUDIO_SERVICE_TYPE_KARAOKE;
    1596             : 
    1597             :     /* get output buffer */
    1598        2107 :     frame->nb_samples = s->num_blocks * AC3_BLOCK_SIZE;
    1599        2107 :     if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
    1600           0 :         return ret;
    1601             : 
    1602             :     /* decode the audio blocks */
    1603        2107 :     channel_map = ff_ac3_dec_channel_map[s->output_mode & ~AC3_OUTPUT_LFEON][s->lfe_on];
    1604       16856 :     for (ch = 0; ch < AC3_MAX_CHANNELS; ch++) {
    1605       14749 :         output[ch] = s->output[ch];
    1606       14749 :         s->outptr[ch] = s->output[ch];
    1607             :     }
    1608        8541 :     for (ch = 0; ch < s->channels; ch++) {
    1609        6434 :         if (ch < s->out_channels)
    1610        4904 :             s->outptr[channel_map[ch]] = (SHORTFLOAT *)frame->data[ch];
    1611             :     }
    1612       14264 :     for (blk = 0; blk < s->num_blocks; blk++) {
    1613       12157 :         if (!err && decode_audio_block(s, blk)) {
    1614           0 :             av_log(avctx, AV_LOG_ERROR, "error decoding the audio block\n");
    1615           0 :             err = 1;
    1616             :         }
    1617       12157 :         if (err)
    1618         138 :             for (ch = 0; ch < s->out_channels; ch++)
    1619          96 :                 memcpy(((SHORTFLOAT*)frame->data[ch]) + AC3_BLOCK_SIZE*blk, output[ch], AC3_BLOCK_SIZE*sizeof(SHORTFLOAT));
    1620       38671 :         for (ch = 0; ch < s->out_channels; ch++)
    1621       26514 :             output[ch] = s->outptr[channel_map[ch]];
    1622       38671 :         for (ch = 0; ch < s->out_channels; ch++) {
    1623       26514 :             if (!ch || channel_map[ch])
    1624       26514 :                 s->outptr[channel_map[ch]] += AC3_BLOCK_SIZE;
    1625             :         }
    1626             :     }
    1627             : 
    1628        2107 :     frame->decode_error_flags = err ? FF_DECODE_ERROR_INVALID_BITSTREAM : 0;
    1629             : 
    1630             :     /* keep last block for error concealment in next frame */
    1631        7011 :     for (ch = 0; ch < s->out_channels; ch++)
    1632        4904 :         memcpy(s->output[ch], output[ch], AC3_BLOCK_SIZE*sizeof(SHORTFLOAT));
    1633             : 
    1634             :     /*
    1635             :      * AVMatrixEncoding
    1636             :      *
    1637             :      * Check whether the input layout is compatible, and make sure we're not
    1638             :      * downmixing (else the matrix encoding is no longer applicable).
    1639             :      */
    1640        2107 :     matrix_encoding = AV_MATRIX_ENCODING_NONE;
    1641        3533 :     if (s->channel_mode == AC3_CHMODE_STEREO &&
    1642        1426 :         s->channel_mode == (s->output_mode & ~AC3_OUTPUT_LFEON)) {
    1643        2852 :         if (s->dolby_surround_mode == AC3_DSURMOD_ON)
    1644         488 :             matrix_encoding = AV_MATRIX_ENCODING_DOLBY;
    1645         938 :         else if (s->dolby_headphone_mode == AC3_DHEADPHONMOD_ON)
    1646           0 :             matrix_encoding = AV_MATRIX_ENCODING_DOLBYHEADPHONE;
    1647        1110 :     } else if (s->channel_mode >= AC3_CHMODE_2F2R &&
    1648         429 :                s->channel_mode == (s->output_mode & ~AC3_OUTPUT_LFEON)) {
    1649         201 :         switch (s->dolby_surround_ex_mode) {
    1650           0 :         case AC3_DSUREXMOD_ON: // EX or PLIIx
    1651           0 :             matrix_encoding = AV_MATRIX_ENCODING_DOLBYEX;
    1652           0 :             break;
    1653           0 :         case AC3_DSUREXMOD_PLIIZ:
    1654           0 :             matrix_encoding = AV_MATRIX_ENCODING_DPLIIZ;
    1655           0 :             break;
    1656         201 :         default: // not indicated or off
    1657         201 :             break;
    1658             :         }
    1659         480 :     }
    1660        2107 :     if ((ret = ff_side_data_update_matrix_encoding(frame, matrix_encoding)) < 0)
    1661           0 :         return ret;
    1662             : 
    1663             :     /* AVDownmixInfo */
    1664        2107 :     if ((downmix_info = av_downmix_info_update_side_data(frame))) {
    1665        2107 :         switch (s->preferred_downmix) {
    1666          47 :         case AC3_DMIXMOD_LTRT:
    1667          47 :             downmix_info->preferred_downmix_type = AV_DOWNMIX_TYPE_LTRT;
    1668          47 :             break;
    1669           0 :         case AC3_DMIXMOD_LORO:
    1670           0 :             downmix_info->preferred_downmix_type = AV_DOWNMIX_TYPE_LORO;
    1671           0 :             break;
    1672          97 :         case AC3_DMIXMOD_DPLII:
    1673          97 :             downmix_info->preferred_downmix_type = AV_DOWNMIX_TYPE_DPLII;
    1674          97 :             break;
    1675        1963 :         default:
    1676        1963 :             downmix_info->preferred_downmix_type = AV_DOWNMIX_TYPE_UNKNOWN;
    1677        1963 :             break;
    1678             :         }
    1679        2107 :         downmix_info->center_mix_level        = gain_levels[s->       center_mix_level];
    1680        2107 :         downmix_info->center_mix_level_ltrt   = gain_levels[s->  center_mix_level_ltrt];
    1681        2107 :         downmix_info->surround_mix_level      = gain_levels[s->     surround_mix_level];
    1682        2107 :         downmix_info->surround_mix_level_ltrt = gain_levels[s->surround_mix_level_ltrt];
    1683        2107 :         if (s->lfe_mix_level_exists)
    1684         144 :             downmix_info->lfe_mix_level       = gain_levels_lfe[s->lfe_mix_level];
    1685             :         else
    1686        1963 :             downmix_info->lfe_mix_level       = 0.0; // -inf dB
    1687             :     } else
    1688           0 :         return AVERROR(ENOMEM);
    1689             : 
    1690        2107 :     *got_frame_ptr = 1;
    1691             : 
    1692        2107 :     return FFMIN(buf_size, s->frame_size);
    1693             : }
    1694             : 
    1695             : /**
    1696             :  * Uninitialize the AC-3 decoder.
    1697             :  */
    1698          42 : static av_cold int ac3_decode_end(AVCodecContext *avctx)
    1699             : {
    1700          42 :     AC3DecodeContext *s = avctx->priv_data;
    1701          42 :     ff_mdct_end(&s->imdct_512);
    1702          42 :     ff_mdct_end(&s->imdct_256);
    1703          42 :     av_freep(&s->fdsp);
    1704          42 :     av_freep(&s->downmix_coeffs[0]);
    1705             : 
    1706          42 :     return 0;
    1707             : }
    1708             : 
    1709             : #define OFFSET(x) offsetof(AC3DecodeContext, x)
    1710             : #define PAR (AV_OPT_FLAG_DECODING_PARAM | AV_OPT_FLAG_AUDIO_PARAM)

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