LCOV - code coverage report
Current view: top level - src/libavcodec - ac3dec.c (source / functions) Hit Total Coverage
Test: coverage.info Lines: 682 841 81.1 %
Date: 2017-01-23 11:54:22 Functions: 19 19 100.0 %

          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       27288 : symmetric_dequant(int code, int levels)
     116             : {
     117       27288 :     return ((code - (levels >> 1)) * (1 << 24)) / levels;
     118             : }
     119             : 
     120             : /*
     121             :  * Initialize tables at runtime.
     122             :  */
     123          36 : 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        4644 :     for (i = 0; i < 128; i++) {
     130        4608 :         ungroup_3_in_7_bits_tab[i][0] =  i / 25;
     131        4608 :         ungroup_3_in_7_bits_tab[i][1] = (i % 25) / 5;
     132        4608 :         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        1188 :     for (i = 0; i < 32; i++) {
     138             :         /* bap=1 mantissas */
     139        1152 :         b1_mantissas[i][0] = symmetric_dequant(ff_ac3_ungroup_3_in_5_bits_tab[i][0], 3);
     140        1152 :         b1_mantissas[i][1] = symmetric_dequant(ff_ac3_ungroup_3_in_5_bits_tab[i][1], 3);
     141        1152 :         b1_mantissas[i][2] = symmetric_dequant(ff_ac3_ungroup_3_in_5_bits_tab[i][2], 3);
     142             :     }
     143        4644 :     for (i = 0; i < 128; i++) {
     144             :         /* bap=2 mantissas */
     145        4608 :         b2_mantissas[i][0] = symmetric_dequant(ungroup_3_in_7_bits_tab[i][0], 5);
     146        4608 :         b2_mantissas[i][1] = symmetric_dequant(ungroup_3_in_7_bits_tab[i][1], 5);
     147        4608 :         b2_mantissas[i][2] = symmetric_dequant(ungroup_3_in_7_bits_tab[i][2], 5);
     148             : 
     149             :         /* bap=4 mantissas */
     150        4608 :         b4_mantissas[i][0] = symmetric_dequant(i / 11, 11);
     151        4608 :         b4_mantissas[i][1] = symmetric_dequant(i % 11, 11);
     152             :     }
     153             :     /* generate ungrouped mantissa tables
     154             :        reference: Tables 7.21 and 7.23 */
     155         288 :     for (i = 0; i < 7; i++) {
     156             :         /* bap=3 mantissas */
     157         252 :         b3_mantissas[i] = symmetric_dequant(i, 7);
     158             :     }
     159         576 :     for (i = 0; i < 15; i++) {
     160             :         /* bap=5 mantissas */
     161         540 :         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        8738 :     for (i = 0; i < 256; i++) {
     168        8704 :         int v = (i >> 5) - ((i >> 7) << 3) - 5;
     169        8704 :         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        8738 :     for (i = 0; i < 256; i++) {
     175        8704 :         int v = (i >> 4) - ((i >> 7) << 4) - 4;
     176        8704 :         ff_ac3_heavy_dynamic_range_tab[i] = powf(2.0f, v) * ((i & 0xF) | 0x10);
     177             :     }
     178             : #endif
     179          36 : }
     180             : 
     181             : /**
     182             :  * AVCodec initialization
     183             :  */
     184          36 : static av_cold int ac3_decode_init(AVCodecContext *avctx)
     185             : {
     186          36 :     AC3DecodeContext *s = avctx->priv_data;
     187             :     int i;
     188             : 
     189          36 :     s->avctx = avctx;
     190             : 
     191          36 :     ac3_tables_init();
     192          36 :     ff_mdct_init(&s->imdct_256, 8, 1, 1.0);
     193          36 :     ff_mdct_init(&s->imdct_512, 9, 1, 1.0);
     194          36 :     AC3_RENAME(ff_kbd_window_init)(s->window, 5.0, 256);
     195          36 :     ff_bswapdsp_init(&s->bdsp);
     196             : 
     197             : #if (USE_FIXED)
     198           2 :     s->fdsp = avpriv_alloc_fixed_dsp(avctx->flags & AV_CODEC_FLAG_BITEXACT);
     199             : #else
     200          34 :     s->fdsp = avpriv_float_dsp_alloc(avctx->flags & AV_CODEC_FLAG_BITEXACT);
     201          34 :     ff_fmt_convert_init(&s->fmt_conv, avctx);
     202             : #endif
     203             : 
     204          36 :     ff_ac3dsp_init(&s->ac3dsp, avctx->flags & AV_CODEC_FLAG_BITEXACT);
     205          36 :     av_lfg_init(&s->dith_state, 0);
     206             : 
     207             :     if (USE_FIXED)
     208           2 :         avctx->sample_fmt = AV_SAMPLE_FMT_S16P;
     209             :     else
     210          34 :         avctx->sample_fmt = AV_SAMPLE_FMT_FLTP;
     211             : 
     212             :     /* allow downmixing to stereo or mono */
     213          51 :     if (avctx->channels > 1 &&
     214          15 :         avctx->request_channel_layout == AV_CH_LAYOUT_MONO)
     215           0 :         avctx->channels = 1;
     216          41 :     else if (avctx->channels > 2 &&
     217           5 :              avctx->request_channel_layout == AV_CH_LAYOUT_STEREO)
     218           0 :         avctx->channels = 2;
     219          36 :     s->downmixed = 1;
     220             : 
     221         288 :     for (i = 0; i < AC3_MAX_CHANNELS; i++) {
     222         252 :         s->xcfptr[i] = s->transform_coeffs[i];
     223         252 :         s->dlyptr[i] = s->delay[i];
     224             :     }
     225             : 
     226          36 :     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         958 : static int ac3_parse_header(AC3DecodeContext *s)
     235             : {
     236         958 :     GetBitContext *gbc = &s->gbc;
     237             :     int i;
     238             : 
     239             :     /* read the rest of the bsi. read twice for dual mono mode. */
     240         958 :     i = !s->channel_mode;
     241             :     do {
     242         958 :         s->dialog_normalization[(!s->channel_mode)-i] = -get_bits(gbc, 5);
     243         958 :         if (s->dialog_normalization[(!s->channel_mode)-i] == 0) {
     244           0 :             s->dialog_normalization[(!s->channel_mode)-i] = -31;
     245             :         }
     246         958 :         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         958 :         if (s->compression_exists[(!s->channel_mode)-i] = get_bits1(gbc)) {
     252        1370 :             s->heavy_dynamic_range[(!s->channel_mode)-i] =
     253         685 :                 AC3_HEAVY_RANGE(get_bits(gbc, 8));
     254             :         }
     255         958 :         if (get_bits1(gbc))
     256           0 :             skip_bits(gbc, 8); //skip language code
     257         958 :         if (get_bits1(gbc))
     258         433 :             skip_bits(gbc, 7); //skip audio production information
     259         958 :     } while (i--);
     260             : 
     261         958 :     skip_bits(gbc, 2); //skip copyright bit and original bitstream bit
     262             : 
     263             :     /* skip the timecodes or parse the Alternate Bit Stream Syntax */
     264         958 :     if (s->bitstream_id != 6) {
     265         958 :         if (get_bits1(gbc))
     266           0 :             skip_bits(gbc, 14); //skip timecode1
     267         958 :         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         958 :     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         958 :     return 0;
     293             : }
     294             : 
     295             : /**
     296             :  * Common function to parse AC-3 or E-AC-3 frame header
     297             :  */
     298        1993 : static int parse_frame_header(AC3DecodeContext *s)
     299             : {
     300        1993 :     AC3HeaderInfo hdr, *phdr=&hdr;
     301             :     int err;
     302             : 
     303        1993 :     err = avpriv_ac3_parse_header(&s->gbc, &phdr);
     304        1993 :     if (err)
     305           0 :         return err;
     306             : 
     307             :     /* get decoding parameters from header info */
     308        1993 :     s->bit_alloc_params.sr_code     = hdr.sr_code;
     309        1993 :     s->bitstream_id                 = hdr.bitstream_id;
     310        1993 :     s->bitstream_mode               = hdr.bitstream_mode;
     311        1993 :     s->channel_mode                 = hdr.channel_mode;
     312        1993 :     s->lfe_on                       = hdr.lfe_on;
     313        1993 :     s->bit_alloc_params.sr_shift    = hdr.sr_shift;
     314        1993 :     s->sample_rate                  = hdr.sample_rate;
     315        1993 :     s->bit_rate                     = hdr.bit_rate;
     316        1993 :     s->channels                     = hdr.channels;
     317        1993 :     s->fbw_channels                 = s->channels - s->lfe_on;
     318        1993 :     s->lfe_ch                       = s->fbw_channels + 1;
     319        1993 :     s->frame_size                   = hdr.frame_size;
     320        1993 :     s->preferred_downmix            = AC3_DMIXMOD_NOTINDICATED;
     321        1993 :     s->center_mix_level             = hdr.center_mix_level;
     322        1993 :     s->center_mix_level_ltrt        = 4; // -3.0dB
     323        1993 :     s->surround_mix_level           = hdr.surround_mix_level;
     324        1993 :     s->surround_mix_level_ltrt      = 4; // -3.0dB
     325        1993 :     s->lfe_mix_level_exists         = 0;
     326        1993 :     s->num_blocks                   = hdr.num_blocks;
     327        1993 :     s->frame_type                   = hdr.frame_type;
     328        1993 :     s->substreamid                  = hdr.substreamid;
     329        1993 :     s->dolby_surround_mode          = hdr.dolby_surround_mode;
     330        1993 :     s->dolby_surround_ex_mode       = AC3_DSUREXMOD_NOTINDICATED;
     331        1993 :     s->dolby_headphone_mode         = AC3_DHEADPHONMOD_NOTINDICATED;
     332             : 
     333        1993 :     if (s->lfe_on) {
     334         315 :         s->start_freq[s->lfe_ch]     = 0;
     335         315 :         s->end_freq[s->lfe_ch]       = 7;
     336         315 :         s->num_exp_groups[s->lfe_ch] = 2;
     337         315 :         s->channel_in_cpl[s->lfe_ch] = 0;
     338             :     }
     339             : 
     340        1993 :     if (s->bitstream_id <= 10) {
     341         958 :         s->eac3                  = 0;
     342         958 :         s->snr_offset_strategy   = 2;
     343         958 :         s->block_switch_syntax   = 1;
     344         958 :         s->dither_flag_syntax    = 1;
     345         958 :         s->bit_allocation_syntax = 1;
     346         958 :         s->fast_gain_syntax      = 0;
     347         958 :         s->first_cpl_leak        = 0;
     348         958 :         s->dba_syntax            = 1;
     349         958 :         s->skip_syntax           = 1;
     350         958 :         memset(s->channel_uses_aht, 0, sizeof(s->channel_uses_aht));
     351         958 :         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         303 : static void set_downmix_coeffs(AC3DecodeContext *s)
     366             : {
     367             :     int i;
     368         303 :     float cmix = gain_levels[s->  center_mix_level];
     369         303 :     float smix = gain_levels[s->surround_mix_level];
     370             :     float norm0, norm1;
     371             :     float downmix_coeffs[AC3_MAX_CHANNELS][2];
     372             : 
     373        1629 :     for (i = 0; i < s->fbw_channels; i++) {
     374        1326 :         downmix_coeffs[i][0] = gain_levels[ac3_default_coeffs[s->channel_mode][i][0]];
     375        1326 :         downmix_coeffs[i][1] = gain_levels[ac3_default_coeffs[s->channel_mode][i][1]];
     376             :     }
     377         303 :     if (s->channel_mode > 1 && s->channel_mode & 1) {
     378         303 :         downmix_coeffs[1][0] = downmix_coeffs[1][1] = cmix;
     379             :     }
     380         303 :     if (s->channel_mode == AC3_CHMODE_2F1R || s->channel_mode == AC3_CHMODE_3F1R) {
     381         189 :         int nf = s->channel_mode - 2;
     382         189 :         downmix_coeffs[nf][0] = downmix_coeffs[nf][1] = smix * LEVEL_MINUS_3DB;
     383             :     }
     384         303 :     if (s->channel_mode == AC3_CHMODE_2F2R || s->channel_mode == AC3_CHMODE_3F2R) {
     385         114 :         int nf = s->channel_mode - 4;
     386         114 :         downmix_coeffs[nf][0] = downmix_coeffs[nf+1][1] = smix;
     387             :     }
     388             : 
     389             :     /* renormalize */
     390         303 :     norm0 = norm1 = 0.0;
     391        1629 :     for (i = 0; i < s->fbw_channels; i++) {
     392        1326 :         norm0 += downmix_coeffs[i][0];
     393        1326 :         norm1 += downmix_coeffs[i][1];
     394             :     }
     395         303 :     norm0 = 1.0f / norm0;
     396         303 :     norm1 = 1.0f / norm1;
     397        1629 :     for (i = 0; i < s->fbw_channels; i++) {
     398        1326 :         downmix_coeffs[i][0] *= norm0;
     399        1326 :         downmix_coeffs[i][1] *= norm1;
     400             :     }
     401             : 
     402         303 :     if (s->output_mode == AC3_CHMODE_MONO) {
     403         972 :         for (i = 0; i < s->fbw_channels; i++)
     404        2367 :             downmix_coeffs[i][0] = (downmix_coeffs[i][0] +
     405        1578 :                                     downmix_coeffs[i][1]) * LEVEL_MINUS_3DB;
     406             :     }
     407        1629 :     for (i = 0; i < s->fbw_channels; i++) {
     408        1326 :         s->downmix_coeffs[i][0] = FIXR12(downmix_coeffs[i][0]);
     409        1326 :         s->downmix_coeffs[i][1] = FIXR12(downmix_coeffs[i][1]);
     410             :     }
     411         303 : }
     412             : 
     413             : /**
     414             :  * Decode the grouped exponents according to exponent strategy.
     415             :  * reference: Section 7.1.3 Exponent Decoding
     416             :  */
     417        9958 : static int decode_exponents(AC3DecodeContext *s,
     418             :                             GetBitContext *gbc, int exp_strategy, int ngrps,
     419             :                             uint8_t absexp, int8_t *dexps)
     420             : {
     421             :     int i, j, grp, group_size;
     422             :     int dexp[256];
     423             :     int expacc, prevexp;
     424             : 
     425             :     /* unpack groups */
     426        9958 :     group_size = exp_strategy + (exp_strategy == EXP_D45);
     427      330451 :     for (grp = 0, i = 0; grp < ngrps; grp++) {
     428      320493 :         expacc = get_bits(gbc, 7);
     429      320493 :         if (expacc >= 125) {
     430           0 :             av_log(s->avctx, AV_LOG_ERROR, "expacc %d is out-of-range\n", expacc);
     431           0 :             return AVERROR_INVALIDDATA;
     432             :         }
     433      320493 :         dexp[i++] = ungroup_3_in_7_bits_tab[expacc][0];
     434      320493 :         dexp[i++] = ungroup_3_in_7_bits_tab[expacc][1];
     435      320493 :         dexp[i++] = ungroup_3_in_7_bits_tab[expacc][2];
     436             :     }
     437             : 
     438             :     /* convert to absolute exps and expand groups */
     439        9958 :     prevexp = absexp;
     440      971437 :     for (i = 0, j = 0; i < ngrps * 3; i++) {
     441      961479 :         prevexp += dexp[i] - 2;
     442      961479 :         if (prevexp > 24U) {
     443           0 :             av_log(s->avctx, AV_LOG_ERROR, "exponent %d is out-of-range\n", prevexp);
     444           0 :             return -1;
     445             :         }
     446      961479 :         switch (group_size) {
     447       71475 :         case 4: dexps[j++] = prevexp;
     448       71475 :                 dexps[j++] = prevexp;
     449      173607 :         case 2: dexps[j++] = prevexp;
     450      961479 :         case 1: dexps[j++] = prevexp;
     451             :         }
     452             :     }
     453        9958 :     return 0;
     454             : }
     455             : 
     456             : /**
     457             :  * Generate transform coefficients for each coupled channel in the coupling
     458             :  * range using the coupling coefficients and coupling coordinates.
     459             :  * reference: Section 7.4.3 Coupling Coordinate Format
     460             :  */
     461        6620 : static void calc_transform_coeffs_cpl(AC3DecodeContext *s)
     462             : {
     463             :     int bin, band, ch;
     464             : 
     465        6620 :     bin = s->start_freq[CPL_CH];
     466       31084 :     for (band = 0; band < s->num_cpl_bands; band++) {
     467       24464 :         int band_start = bin;
     468       24464 :         int band_end = bin + s->cpl_band_sizes[band];
     469       79440 :         for (ch = 1; ch <= s->fbw_channels; ch++) {
     470       54976 :             if (s->channel_in_cpl[ch]) {
     471       54976 :                 int cpl_coord = s->cpl_coords[ch][band] << 5;
     472     1255072 :                 for (bin = band_start; bin < band_end; bin++) {
     473     1200096 :                     s->fixed_coeffs[ch][bin] =
     474     1200096 :                         MULH(s->fixed_coeffs[CPL_CH][bin] * (1 << 4), cpl_coord);
     475             :                 }
     476       54976 :                 if (ch == 2 && s->phase_flags[band]) {
     477           0 :                     for (bin = band_start; bin < band_end; bin++)
     478           0 :                         s->fixed_coeffs[2][bin] = -s->fixed_coeffs[2][bin];
     479             :                 }
     480             :             }
     481             :         }
     482       24464 :         bin = band_end;
     483             :     }
     484        6620 : }
     485             : 
     486             : /**
     487             :  * Grouped mantissas for 3-level 5-level and 11-level quantization
     488             :  */
     489             : typedef struct mant_groups {
     490             :     int b1_mant[2];
     491             :     int b2_mant[2];
     492             :     int b4_mant;
     493             :     int b1;
     494             :     int b2;
     495             :     int b4;
     496             : } mant_groups;
     497             : 
     498             : /**
     499             :  * Decode the transform coefficients for a particular channel
     500             :  * reference: Section 7.3 Quantization and Decoding of Mantissas
     501             :  */
     502       33290 : static void ac3_decode_transform_coeffs_ch(AC3DecodeContext *s, int ch_index, mant_groups *m)
     503             : {
     504       33290 :     int start_freq = s->start_freq[ch_index];
     505       33290 :     int end_freq   = s->end_freq[ch_index];
     506       33290 :     uint8_t *baps  = s->bap[ch_index];
     507       33290 :     int8_t *exps   = s->dexps[ch_index];
     508       33290 :     int32_t *coeffs = s->fixed_coeffs[ch_index];
     509       33290 :     int dither     = (ch_index == CPL_CH) || s->dither_flag[ch_index];
     510       33290 :     GetBitContext *gbc = &s->gbc;
     511             :     int freq;
     512             : 
     513     4254002 :     for (freq = start_freq; freq < end_freq; freq++) {
     514     4220712 :         int bap = baps[freq];
     515             :         int mantissa;
     516     4220712 :         switch (bap) {
     517             :         case 0:
     518             :             /* random noise with approximate range of -0.707 to 0.707 */
     519     1218767 :             if (dither)
     520     1216007 :                 mantissa = (((av_lfg_get(&s->dith_state)>>8)*181)>>8) - 5931008;
     521             :             else
     522        2760 :                 mantissa = 0;
     523     1218767 :             break;
     524             :         case 1:
     525      953460 :             if (m->b1) {
     526      632474 :                 m->b1--;
     527      632474 :                 mantissa = m->b1_mant[m->b1];
     528             :             } else {
     529      320986 :                 int bits      = get_bits(gbc, 5);
     530      320986 :                 mantissa      = b1_mantissas[bits][0];
     531      320986 :                 m->b1_mant[1] = b1_mantissas[bits][1];
     532      320986 :                 m->b1_mant[0] = b1_mantissas[bits][2];
     533      320986 :                 m->b1         = 2;
     534             :             }
     535      953460 :             break;
     536             :         case 2:
     537      408552 :             if (m->b2) {
     538      269361 :                 m->b2--;
     539      269361 :                 mantissa = m->b2_mant[m->b2];
     540             :             } else {
     541      139191 :                 int bits      = get_bits(gbc, 7);
     542      139191 :                 mantissa      = b2_mantissas[bits][0];
     543      139191 :                 m->b2_mant[1] = b2_mantissas[bits][1];
     544      139191 :                 m->b2_mant[0] = b2_mantissas[bits][2];
     545      139191 :                 m->b2         = 2;
     546             :             }
     547      408552 :             break;
     548             :         case 3:
     549      532161 :             mantissa = b3_mantissas[get_bits(gbc, 3)];
     550      532161 :             break;
     551             :         case 4:
     552      327882 :             if (m->b4) {
     553      161570 :                 m->b4 = 0;
     554      161570 :                 mantissa = m->b4_mant;
     555             :             } else {
     556      166312 :                 int bits   = get_bits(gbc, 7);
     557      166312 :                 mantissa   = b4_mantissas[bits][0];
     558      166312 :                 m->b4_mant = b4_mantissas[bits][1];
     559      166312 :                 m->b4      = 1;
     560             :             }
     561      327882 :             break;
     562             :         case 5:
     563      249937 :             mantissa = b5_mantissas[get_bits(gbc, 4)];
     564      249937 :             break;
     565             :         default: /* 6 to 15 */
     566             :             /* Shift mantissa and sign-extend it. */
     567      529953 :             if (bap > 15) {
     568           0 :                 av_log(s->avctx, AV_LOG_ERROR, "bap %d is invalid in plain AC-3\n", bap);
     569           0 :                 bap = 15;
     570             :             }
     571      529953 :             mantissa = (unsigned)get_sbits(gbc, quantization_tab[bap]) << (24 - quantization_tab[bap]);
     572      529953 :             break;
     573             :         }
     574     4220712 :         coeffs[freq] = mantissa >> exps[freq];
     575             :     }
     576       33290 : }
     577             : 
     578             : /**
     579             :  * Remove random dithering from coupling range coefficients with zero-bit
     580             :  * mantissas for coupled channels which do not use dithering.
     581             :  * reference: Section 7.3.4 Dither for Zero Bit Mantissas (bap=0)
     582             :  */
     583       11443 : static void remove_dithering(AC3DecodeContext *s) {
     584             :     int ch, i;
     585             : 
     586       41514 :     for (ch = 1; ch <= s->fbw_channels; ch++) {
     587       30071 :         if (!s->dither_flag[ch] && s->channel_in_cpl[ch]) {
     588           0 :             for (i = s->start_freq[CPL_CH]; i < s->end_freq[CPL_CH]; i++) {
     589           0 :                 if (!s->bap[CPL_CH][i])
     590           0 :                     s->fixed_coeffs[ch][i] = 0;
     591             :             }
     592             :         }
     593             :     }
     594       11443 : }
     595             : 
     596       38078 : static void decode_transform_coeffs_ch(AC3DecodeContext *s, int blk, int ch,
     597             :                                        mant_groups *m)
     598             : {
     599       38078 :     if (!s->channel_uses_aht[ch]) {
     600       33290 :         ac3_decode_transform_coeffs_ch(s, ch, m);
     601             :     } else {
     602             :         /* if AHT is used, mantissas for all blocks are encoded in the first
     603             :            block of the frame. */
     604             :         int bin;
     605        4788 :         if (CONFIG_EAC3_DECODER && !blk)
     606         798 :             ff_eac3_decode_transform_coeffs_aht_ch(s, ch);
     607      591120 :         for (bin = s->start_freq[ch]; bin < s->end_freq[ch]; bin++) {
     608      586332 :             s->fixed_coeffs[ch][bin] = s->pre_mantissa[ch][bin][blk] >> s->dexps[ch][bin];
     609             :         }
     610             :     }
     611       38078 : }
     612             : 
     613             : /**
     614             :  * Decode the transform coefficients.
     615             :  */
     616       11443 : static void decode_transform_coeffs(AC3DecodeContext *s, int blk)
     617             : {
     618             :     int ch, end;
     619       11443 :     int got_cplchan = 0;
     620             :     mant_groups m;
     621             : 
     622       11443 :     m.b1 = m.b2 = m.b4 = 0;
     623             : 
     624       42901 :     for (ch = 1; ch <= s->channels; ch++) {
     625             :         /* transform coefficients for full-bandwidth channel */
     626       31458 :         decode_transform_coeffs_ch(s, blk, ch, &m);
     627             :         /* transform coefficients for coupling channel come right after the
     628             :            coefficients for the first coupled channel*/
     629       31458 :         if (s->channel_in_cpl[ch])  {
     630       16264 :             if (!got_cplchan) {
     631        6620 :                 decode_transform_coeffs_ch(s, blk, CPL_CH, &m);
     632        6620 :                 calc_transform_coeffs_cpl(s);
     633        6620 :                 got_cplchan = 1;
     634             :             }
     635       16264 :             end = s->end_freq[CPL_CH];
     636             :         } else {
     637       15194 :             end = s->end_freq[ch];
     638             :         }
     639             :         do
     640     2555436 :             s->fixed_coeffs[ch][end] = 0;
     641     2555436 :         while (++end < 256);
     642             :     }
     643             : 
     644             :     /* zero the dithered coefficients for appropriate channels */
     645       11443 :     remove_dithering(s);
     646       11443 : }
     647             : 
     648             : /**
     649             :  * Stereo rematrixing.
     650             :  * reference: Section 7.5.4 Rematrixing : Decoding Technique
     651             :  */
     652        8544 : static void do_rematrixing(AC3DecodeContext *s)
     653             : {
     654             :     int bnd, i;
     655             :     int end, bndend;
     656             : 
     657        8544 :     end = FFMIN(s->end_freq[1], s->end_freq[2]);
     658             : 
     659       42720 :     for (bnd = 0; bnd < s->num_rematrixing_bands; bnd++) {
     660       34176 :         if (s->rematrixing_flags[bnd]) {
     661       23174 :             bndend = FFMIN(end, ff_ac3_rematrix_band_tab[bnd + 1]);
     662      633686 :             for (i = ff_ac3_rematrix_band_tab[bnd]; i < bndend; i++) {
     663      610512 :                 int tmp0 = s->fixed_coeffs[1][i];
     664      610512 :                 s->fixed_coeffs[1][i] += s->fixed_coeffs[2][i];
     665      610512 :                 s->fixed_coeffs[2][i]  = tmp0 - s->fixed_coeffs[2][i];
     666             :             }
     667             :         }
     668             :     }
     669        8544 : }
     670             : 
     671             : /**
     672             :  * Inverse MDCT Transform.
     673             :  * Convert frequency domain coefficients to time-domain audio samples.
     674             :  * reference: Section 7.9.4 Transformation Equations
     675             :  */
     676       11443 : static inline void do_imdct(AC3DecodeContext *s, int channels)
     677             : {
     678             :     int ch;
     679             : 
     680       36861 :     for (ch = 1; ch <= channels; ch++) {
     681       25418 :         if (s->block_switch[ch]) {
     682             :             int i;
     683           6 :             FFTSample *x = s->tmp_output + 128;
     684         774 :             for (i = 0; i < 128; i++)
     685         768 :                 x[i] = s->transform_coeffs[ch][2 * i];
     686           6 :             s->imdct_256.imdct_half(&s->imdct_256, s->tmp_output, x);
     687             : #if USE_FIXED
     688           4 :             s->fdsp->vector_fmul_window_scaled(s->outptr[ch - 1], s->delay[ch - 1],
     689           2 :                                        s->tmp_output, s->window, 128, 8);
     690             : #else
     691           8 :             s->fdsp->vector_fmul_window(s->outptr[ch - 1], s->delay[ch - 1],
     692           4 :                                        s->tmp_output, s->window, 128);
     693             : #endif
     694         774 :             for (i = 0; i < 128; i++)
     695         768 :                 x[i] = s->transform_coeffs[ch][2 * i + 1];
     696           6 :             s->imdct_256.imdct_half(&s->imdct_256, s->delay[ch - 1], x);
     697             :         } else {
     698       25412 :             s->imdct_512.imdct_half(&s->imdct_512, s->tmp_output, s->transform_coeffs[ch]);
     699             : #if USE_FIXED
     700        3866 :             s->fdsp->vector_fmul_window_scaled(s->outptr[ch - 1], s->delay[ch - 1],
     701        1933 :                                        s->tmp_output, s->window, 128, 8);
     702             : #else
     703       46958 :             s->fdsp->vector_fmul_window(s->outptr[ch - 1], s->delay[ch - 1],
     704       23479 :                                        s->tmp_output, s->window, 128);
     705             : #endif
     706       25412 :             memcpy(s->delay[ch - 1], s->tmp_output + 128, 128 * sizeof(FFTSample));
     707             :         }
     708             :     }
     709       11443 : }
     710             : 
     711             : /**
     712             :  * Upmix delay samples from stereo to original channel layout.
     713             :  */
     714           6 : static void ac3_upmix_delay(AC3DecodeContext *s)
     715             : {
     716           6 :     int channel_data_size = sizeof(s->delay[0]);
     717           6 :     switch (s->channel_mode) {
     718             :     case AC3_CHMODE_DUALMONO:
     719             :     case AC3_CHMODE_STEREO:
     720             :         /* upmix mono to stereo */
     721           2 :         memcpy(s->delay[1], s->delay[0], channel_data_size);
     722           2 :         break;
     723             :     case AC3_CHMODE_2F2R:
     724           0 :         memset(s->delay[3], 0, channel_data_size);
     725             :     case AC3_CHMODE_2F1R:
     726           0 :         memset(s->delay[2], 0, channel_data_size);
     727           0 :         break;
     728             :     case AC3_CHMODE_3F2R:
     729           0 :         memset(s->delay[4], 0, channel_data_size);
     730             :     case AC3_CHMODE_3F1R:
     731           4 :         memset(s->delay[3], 0, channel_data_size);
     732             :     case AC3_CHMODE_3F:
     733           4 :         memcpy(s->delay[2], s->delay[1], channel_data_size);
     734           4 :         memset(s->delay[1], 0, channel_data_size);
     735           4 :         break;
     736             :     }
     737           6 : }
     738             : 
     739             : /**
     740             :  * Decode band structure for coupling, spectral extension, or enhanced coupling.
     741             :  * The band structure defines how many subbands are in each band.  For each
     742             :  * subband in the range, 1 means it is combined with the previous band, and 0
     743             :  * means that it starts a new band.
     744             :  *
     745             :  * @param[in] gbc bit reader context
     746             :  * @param[in] blk block number
     747             :  * @param[in] eac3 flag to indicate E-AC-3
     748             :  * @param[in] ecpl flag to indicate enhanced coupling
     749             :  * @param[in] start_subband subband number for start of range
     750             :  * @param[in] end_subband subband number for end of range
     751             :  * @param[in] default_band_struct default band structure table
     752             :  * @param[out] num_bands number of bands (optionally NULL)
     753             :  * @param[out] band_sizes array containing the number of bins in each band (optionally NULL)
     754             :  */
     755        1639 : static void decode_band_structure(GetBitContext *gbc, int blk, int eac3,
     756             :                                   int ecpl, int start_subband, int end_subband,
     757             :                                   const uint8_t *default_band_struct,
     758             :                                   int *num_bands, uint8_t *band_sizes)
     759             : {
     760        1639 :     int subbnd, bnd, n_subbands, n_bands=0;
     761             :     uint8_t bnd_sz[22];
     762             :     uint8_t coded_band_struct[22];
     763             :     const uint8_t *band_struct;
     764             : 
     765        1639 :     n_subbands = end_subband - start_subband;
     766             : 
     767             :     /* decode band structure from bitstream or use default */
     768        1639 :     if (!eac3 || get_bits1(gbc)) {
     769        5803 :         for (subbnd = 0; subbnd < n_subbands - 1; subbnd++) {
     770        4567 :             coded_band_struct[subbnd] = get_bits1(gbc);
     771             :         }
     772        1236 :         band_struct = coded_band_struct;
     773         403 :     } else if (!blk) {
     774         403 :         band_struct = &default_band_struct[start_subband+1];
     775             :     } else {
     776             :         /* no change in band structure */
     777           0 :         return;
     778             :     }
     779             : 
     780             :     /* calculate number of bands and band sizes based on band structure.
     781             :        note that the first 4 subbands in enhanced coupling span only 6 bins
     782             :        instead of 12. */
     783        1639 :     if (num_bands || band_sizes ) {
     784        1639 :         n_bands = n_subbands;
     785        1639 :         bnd_sz[0] = ecpl ? 6 : 12;
     786        8338 :         for (bnd = 0, subbnd = 1; subbnd < n_subbands; subbnd++) {
     787        6699 :             int subbnd_size = (ecpl && subbnd < 4) ? 6 : 12;
     788        6699 :             if (band_struct[subbnd - 1]) {
     789        3047 :                 n_bands--;
     790        3047 :                 bnd_sz[bnd] += subbnd_size;
     791             :             } else {
     792        3652 :                 bnd_sz[++bnd] = subbnd_size;
     793             :             }
     794             :         }
     795             :     }
     796             : 
     797             :     /* set optional output params */
     798        1639 :     if (num_bands)
     799        1639 :         *num_bands = n_bands;
     800        1639 :     if (band_sizes)
     801        1639 :         memcpy(band_sizes, bnd_sz, n_bands);
     802             : }
     803             : 
     804             : /**
     805             :  * Decode a single audio block from the AC-3 bitstream.
     806             :  */
     807       11443 : static int decode_audio_block(AC3DecodeContext *s, int blk)
     808             : {
     809       11443 :     int fbw_channels = s->fbw_channels;
     810       11443 :     int channel_mode = s->channel_mode;
     811             :     int i, bnd, seg, ch;
     812             :     int different_transforms;
     813             :     int downmix_output;
     814             :     int cpl_in_use;
     815       11443 :     GetBitContext *gbc = &s->gbc;
     816       11443 :     uint8_t bit_alloc_stages[AC3_MAX_CHANNELS] = { 0 };
     817             : 
     818             :     /* block switch flags */
     819       11443 :     different_transforms = 0;
     820       11443 :     if (s->block_switch_syntax) {
     821       23202 :         for (ch = 1; ch <= fbw_channels; ch++) {
     822       17484 :             s->block_switch[ch] = get_bits1(gbc);
     823       17484 :             if (ch > 1 && s->block_switch[ch] != s->block_switch[1])
     824           6 :                 different_transforms = 1;
     825             :         }
     826             :     }
     827             : 
     828             :     /* dithering flags */
     829       11443 :     if (s->dither_flag_syntax) {
     830       23202 :         for (ch = 1; ch <= fbw_channels; ch++) {
     831       17484 :             s->dither_flag[ch] = get_bits1(gbc);
     832             :         }
     833             :     }
     834             : 
     835             :     /* dynamic range */
     836       11443 :     i = !s->channel_mode;
     837             :     do {
     838       11443 :         if (get_bits1(gbc)) {
     839             :             /* Allow asymmetric application of DRC when drc_scale > 1.
     840             :                Amplification of quiet sounds is enhanced */
     841        1472 :             int range_bits = get_bits(gbc, 8);
     842        1472 :             INTFLOAT range = AC3_RANGE(range_bits);
     843        1472 :             if (range_bits <= 127 || s->drc_scale <= 1.0)
     844        1374 :                 s->dynamic_range[i] = AC3_DYNAMIC_RANGE(range);
     845             :             else
     846          98 :                 s->dynamic_range[i] = range;
     847        9971 :         } else if (blk == 0) {
     848         700 :             s->dynamic_range[i] = AC3_DYNAMIC_RANGE1;
     849             :         }
     850       11443 :     } while (i--);
     851             : 
     852             :     /* spectral extension strategy */
     853       11443 :     if (s->eac3 && (!blk || get_bits1(gbc))) {
     854        1035 :         s->spx_in_use = get_bits1(gbc);
     855        1035 :         if (s->spx_in_use) {
     856             :             int dst_start_freq, dst_end_freq, src_start_freq,
     857             :                 start_subband, end_subband;
     858             : 
     859             :             /* determine which channels use spx */
     860         535 :             if (s->channel_mode == AC3_CHMODE_MONO) {
     861           0 :                 s->channel_uses_spx[1] = 1;
     862             :             } else {
     863        1746 :                 for (ch = 1; ch <= fbw_channels; ch++)
     864        1211 :                     s->channel_uses_spx[ch] = get_bits1(gbc);
     865             :             }
     866             : 
     867             :             /* get the frequency bins of the spx copy region and the spx start
     868             :                and end subbands */
     869         535 :             dst_start_freq = get_bits(gbc, 2);
     870         535 :             start_subband  = get_bits(gbc, 3) + 2;
     871         535 :             if (start_subband > 7)
     872         488 :                 start_subband += start_subband - 7;
     873         535 :             end_subband    = get_bits(gbc, 3) + 5;
     874             : #if USE_FIXED
     875           0 :             s->spx_dst_end_freq = end_freq_inv_tab[end_subband-5];
     876             : #endif
     877         535 :             if (end_subband   > 7)
     878         535 :                 end_subband   += end_subband   - 7;
     879         535 :             dst_start_freq = dst_start_freq * 12 + 25;
     880         535 :             src_start_freq = start_subband  * 12 + 25;
     881         535 :             dst_end_freq   = end_subband    * 12 + 25;
     882             : 
     883             :             /* check validity of spx ranges */
     884         535 :             if (start_subband >= end_subband) {
     885           0 :                 av_log(s->avctx, AV_LOG_ERROR, "invalid spectral extension "
     886             :                        "range (%d >= %d)\n", start_subband, end_subband);
     887           0 :                 return AVERROR_INVALIDDATA;
     888             :             }
     889         535 :             if (dst_start_freq >= src_start_freq) {
     890           0 :                 av_log(s->avctx, AV_LOG_ERROR, "invalid spectral extension "
     891             :                        "copy start bin (%d >= %d)\n", dst_start_freq, src_start_freq);
     892           0 :                 return AVERROR_INVALIDDATA;
     893             :             }
     894             : 
     895         535 :             s->spx_dst_start_freq = dst_start_freq;
     896         535 :             s->spx_src_start_freq = src_start_freq;
     897             :             if (!USE_FIXED)
     898         535 :                 s->spx_dst_end_freq   = dst_end_freq;
     899             : 
     900         535 :             decode_band_structure(gbc, blk, s->eac3, 0,
     901             :                                   start_subband, end_subband,
     902             :                                   ff_eac3_default_spx_band_struct,
     903             :                                   &s->num_spx_bands,
     904         535 :                                   s->spx_band_sizes);
     905             :         }
     906             :     }
     907       11443 :     if (!s->eac3 || !s->spx_in_use) {
     908        8233 :         s->spx_in_use = 0;
     909       31038 :         for (ch = 1; ch <= fbw_channels; ch++) {
     910       22805 :             s->channel_uses_spx[ch] = 0;
     911       22805 :             s->first_spx_coords[ch] = 1;
     912             :         }
     913             :     }
     914             : 
     915             :     /* spectral extension coordinates */
     916       11443 :     if (s->spx_in_use) {
     917       10476 :         for (ch = 1; ch <= fbw_channels; ch++) {
     918        7266 :             if (s->channel_uses_spx[ch]) {
     919        7266 :                 if (s->first_spx_coords[ch] || get_bits1(gbc)) {
     920             :                     INTFLOAT spx_blend;
     921             :                     int bin, master_spx_coord;
     922             : 
     923        1950 :                     s->first_spx_coords[ch] = 0;
     924        1950 :                     spx_blend = AC3_SPX_BLEND(get_bits(gbc, 5));
     925        1950 :                     master_spx_coord = get_bits(gbc, 2) * 3;
     926             : 
     927        1950 :                     bin = s->spx_src_start_freq;
     928        6834 :                     for (bnd = 0; bnd < s->num_spx_bands; bnd++) {
     929        4884 :                         int bandsize = s->spx_band_sizes[bnd];
     930             :                         int spx_coord_exp, spx_coord_mant;
     931             :                         INTFLOAT nratio, sblend, nblend;
     932             : #if USE_FIXED
     933             :                         /* calculate blending factors */
     934           0 :                         int64_t accu = ((bin << 23) + (bandsize << 22))
     935           0 :                                      * (int64_t)s->spx_dst_end_freq;
     936           0 :                         nratio = (int)(accu >> 32);
     937           0 :                         nratio -= spx_blend << 18;
     938             : 
     939           0 :                         if (nratio < 0) {
     940           0 :                             nblend = 0;
     941           0 :                             sblend = 0x800000;
     942           0 :                         } else if (nratio > 0x7fffff) {
     943           0 :                             nblend = 14529495; // sqrt(3) in FP.23
     944           0 :                             sblend = 0;
     945             :                         } else {
     946           0 :                             nblend = fixed_sqrt(nratio, 23);
     947           0 :                             accu = (int64_t)nblend * 1859775393;
     948           0 :                             nblend = (int)((accu + (1<<29)) >> 30);
     949           0 :                             sblend = fixed_sqrt(0x800000 - nratio, 23);
     950             :                         }
     951             : #else
     952             :                         float spx_coord;
     953             : 
     954             :                         /* calculate blending factors */
     955        4884 :                         nratio = ((float)((bin + (bandsize >> 1))) / s->spx_dst_end_freq) - spx_blend;
     956        4884 :                         nratio = av_clipf(nratio, 0.0f, 1.0f);
     957        4884 :                         nblend = sqrtf(3.0f * nratio); // noise is scaled by sqrt(3)
     958             :                                                        // to give unity variance
     959        4884 :                         sblend = sqrtf(1.0f - nratio);
     960             : #endif
     961        4884 :                         bin += bandsize;
     962             : 
     963             :                         /* decode spx coordinates */
     964        4884 :                         spx_coord_exp  = get_bits(gbc, 4);
     965        4884 :                         spx_coord_mant = get_bits(gbc, 2);
     966        4884 :                         if (spx_coord_exp == 15) spx_coord_mant <<= 1;
     967        4178 :                         else                     spx_coord_mant += 4;
     968        4884 :                         spx_coord_mant <<= (25 - spx_coord_exp - master_spx_coord);
     969             : 
     970             :                         /* multiply noise and signal blending factors by spx coordinate */
     971             : #if USE_FIXED
     972           0 :                         accu = (int64_t)nblend * spx_coord_mant;
     973           0 :                         s->spx_noise_blend[ch][bnd]  = (int)((accu + (1<<22)) >> 23);
     974           0 :                         accu = (int64_t)sblend * spx_coord_mant;
     975           0 :                         s->spx_signal_blend[ch][bnd] = (int)((accu + (1<<22)) >> 23);
     976             : #else
     977        4884 :                         spx_coord = spx_coord_mant * (1.0f / (1 << 23));
     978        4884 :                         s->spx_noise_blend [ch][bnd] = nblend * spx_coord;
     979        4884 :                         s->spx_signal_blend[ch][bnd] = sblend * spx_coord;
     980             : #endif
     981             :                     }
     982             :                 }
     983             :             } else {
     984           0 :                 s->first_spx_coords[ch] = 1;
     985             :             }
     986             :         }
     987             :     }
     988             : 
     989             :     /* coupling strategy */
     990       11443 :     if (s->eac3 ? s->cpl_strategy_exists[blk] : get_bits1(gbc)) {
     991        1990 :         memset(bit_alloc_stages, 3, AC3_MAX_CHANNELS);
     992        1990 :         if (!s->eac3)
     993         955 :             s->cpl_in_use[blk] = get_bits1(gbc);
     994        1990 :         if (s->cpl_in_use[blk]) {
     995             :             /* coupling in use */
     996             :             int cpl_start_subband, cpl_end_subband;
     997             : 
     998        1104 :             if (channel_mode < AC3_CHMODE_STEREO) {
     999           0 :                 av_log(s->avctx, AV_LOG_ERROR, "coupling not allowed in mono or dual-mono\n");
    1000           0 :                 return AVERROR_INVALIDDATA;
    1001             :             }
    1002             : 
    1003             :             /* check for enhanced coupling */
    1004        1104 :             if (s->eac3 && get_bits1(gbc)) {
    1005             :                 /* TODO: parse enhanced coupling strategy info */
    1006           0 :                 avpriv_request_sample(s->avctx, "Enhanced coupling");
    1007           0 :                 return AVERROR_PATCHWELCOME;
    1008             :             }
    1009             : 
    1010             :             /* determine which channels are coupled */
    1011        1104 :             if (s->eac3 && s->channel_mode == AC3_CHMODE_STEREO) {
    1012         403 :                 s->channel_in_cpl[1] = 1;
    1013         403 :                 s->channel_in_cpl[2] = 1;
    1014             :             } else {
    1015        2607 :                 for (ch = 1; ch <= fbw_channels; ch++)
    1016        1906 :                     s->channel_in_cpl[ch] = get_bits1(gbc);
    1017             :             }
    1018             : 
    1019             :             /* phase flags in use */
    1020        1104 :             if (channel_mode == AC3_CHMODE_STEREO)
    1021         936 :                 s->phase_flags_in_use = get_bits1(gbc);
    1022             : 
    1023             :             /* coupling frequency range */
    1024        1104 :             cpl_start_subband = get_bits(gbc, 4);
    1025        2208 :             cpl_end_subband = s->spx_in_use ? (s->spx_src_start_freq - 37) / 12 :
    1026        1104 :                                               get_bits(gbc, 4) + 3;
    1027        1104 :             if (cpl_start_subband >= cpl_end_subband) {
    1028           0 :                 av_log(s->avctx, AV_LOG_ERROR, "invalid coupling range (%d >= %d)\n",
    1029             :                        cpl_start_subband, cpl_end_subband);
    1030           0 :                 return AVERROR_INVALIDDATA;
    1031             :             }
    1032        1104 :             s->start_freq[CPL_CH] = cpl_start_subband * 12 + 37;
    1033        1104 :             s->end_freq[CPL_CH]   = cpl_end_subband   * 12 + 37;
    1034             : 
    1035        1104 :             decode_band_structure(gbc, blk, s->eac3, 0, cpl_start_subband,
    1036             :                                   cpl_end_subband,
    1037             :                                   ff_eac3_default_cpl_band_struct,
    1038        1104 :                                   &s->num_cpl_bands, s->cpl_band_sizes);
    1039             :         } else {
    1040             :             /* coupling not in use */
    1041        3594 :             for (ch = 1; ch <= fbw_channels; ch++) {
    1042        2708 :                 s->channel_in_cpl[ch] = 0;
    1043        2708 :                 s->first_cpl_coords[ch] = 1;
    1044             :             }
    1045         886 :             s->first_cpl_leak = s->eac3;
    1046         886 :             s->phase_flags_in_use = 0;
    1047             :         }
    1048        9453 :     } else if (!s->eac3) {
    1049        4763 :         if (!blk) {
    1050           0 :             av_log(s->avctx, AV_LOG_ERROR, "new coupling strategy must "
    1051             :                    "be present in block 0\n");
    1052           0 :             return AVERROR_INVALIDDATA;
    1053             :         } else {
    1054        4763 :             s->cpl_in_use[blk] = s->cpl_in_use[blk-1];
    1055             :         }
    1056             :     }
    1057       11443 :     cpl_in_use = s->cpl_in_use[blk];
    1058             : 
    1059             :     /* coupling coordinates */
    1060       11443 :     if (cpl_in_use) {
    1061        6620 :         int cpl_coords_exist = 0;
    1062             : 
    1063       22884 :         for (ch = 1; ch <= fbw_channels; ch++) {
    1064       16264 :             if (s->channel_in_cpl[ch]) {
    1065       20519 :                 if ((s->eac3 && s->first_cpl_coords[ch]) || get_bits1(gbc)) {
    1066             :                     int master_cpl_coord, cpl_coord_exp, cpl_coord_mant;
    1067        4255 :                     s->first_cpl_coords[ch] = 0;
    1068        4255 :                     cpl_coords_exist = 1;
    1069        4255 :                     master_cpl_coord = 3 * get_bits(gbc, 2);
    1070       16565 :                     for (bnd = 0; bnd < s->num_cpl_bands; bnd++) {
    1071       12310 :                         cpl_coord_exp = get_bits(gbc, 4);
    1072       12310 :                         cpl_coord_mant = get_bits(gbc, 4);
    1073       12310 :                         if (cpl_coord_exp == 15)
    1074        1542 :                             s->cpl_coords[ch][bnd] = cpl_coord_mant << 22;
    1075             :                         else
    1076       10768 :                             s->cpl_coords[ch][bnd] = (cpl_coord_mant + 16) << 21;
    1077       12310 :                         s->cpl_coords[ch][bnd] >>= (cpl_coord_exp + master_cpl_coord);
    1078             :                     }
    1079       12009 :                 } else if (!blk) {
    1080           0 :                     av_log(s->avctx, AV_LOG_ERROR, "new coupling coordinates must "
    1081             :                            "be present in block 0\n");
    1082           0 :                     return AVERROR_INVALIDDATA;
    1083             :                 }
    1084             :             } else {
    1085             :                 /* channel not in coupling */
    1086           0 :                 s->first_cpl_coords[ch] = 1;
    1087             :             }
    1088             :         }
    1089             :         /* phase flags */
    1090        6620 :         if (channel_mode == AC3_CHMODE_STEREO && cpl_coords_exist) {
    1091        4810 :             for (bnd = 0; bnd < s->num_cpl_bands; bnd++) {
    1092        3848 :                 s->phase_flags[bnd] = s->phase_flags_in_use? get_bits1(gbc) : 0;
    1093             :             }
    1094             :         }
    1095             :     }
    1096             : 
    1097             :     /* stereo rematrixing strategy and band structure */
    1098       11443 :     if (channel_mode == AC3_CHMODE_STEREO) {
    1099       11376 :         if ((s->eac3 && !blk) || get_bits1(gbc)) {
    1100        2832 :             s->num_rematrixing_bands = 4;
    1101        2832 :             if (cpl_in_use && s->start_freq[CPL_CH] <= 61) {
    1102           0 :                 s->num_rematrixing_bands -= 1 + (s->start_freq[CPL_CH] == 37);
    1103        2832 :             } else if (s->spx_in_use && s->spx_src_start_freq <= 61) {
    1104           0 :                 s->num_rematrixing_bands--;
    1105             :             }
    1106       14160 :             for (bnd = 0; bnd < s->num_rematrixing_bands; bnd++)
    1107       11328 :                 s->rematrixing_flags[bnd] = get_bits1(gbc);
    1108        5712 :         } else if (!blk) {
    1109           0 :             av_log(s->avctx, AV_LOG_WARNING, "Warning: "
    1110             :                    "new rematrixing strategy not present in block 0\n");
    1111           0 :             s->num_rematrixing_bands = 0;
    1112             :         }
    1113             :     }
    1114             : 
    1115             :     /* exponent strategies for each channel */
    1116       49521 :     for (ch = !cpl_in_use; ch <= s->channels; ch++) {
    1117       38078 :         if (!s->eac3)
    1118       22694 :             s->exp_strategy[blk][ch] = get_bits(gbc, 2 - (ch == s->lfe_ch));
    1119       38078 :         if (s->exp_strategy[blk][ch] != EXP_REUSE)
    1120        9958 :             bit_alloc_stages[ch] = 3;
    1121             :     }
    1122             : 
    1123             :     /* channel bandwidth */
    1124       41514 :     for (ch = 1; ch <= fbw_channels; ch++) {
    1125       30071 :         s->start_freq[ch] = 0;
    1126       30071 :         if (s->exp_strategy[blk][ch] != EXP_REUSE) {
    1127             :             int group_size;
    1128        7509 :             int prev = s->end_freq[ch];
    1129        7509 :             if (s->channel_in_cpl[ch])
    1130        3374 :                 s->end_freq[ch] = s->start_freq[CPL_CH];
    1131        4135 :             else if (s->channel_uses_spx[ch])
    1132        1950 :                 s->end_freq[ch] = s->spx_src_start_freq;
    1133             :             else {
    1134        2185 :                 int bandwidth_code = get_bits(gbc, 6);
    1135        2185 :                 if (bandwidth_code > 60) {
    1136           0 :                     av_log(s->avctx, AV_LOG_ERROR, "bandwidth code = %d > 60\n", bandwidth_code);
    1137           0 :                     return AVERROR_INVALIDDATA;
    1138             :                 }
    1139        2185 :                 s->end_freq[ch] = bandwidth_code * 3 + 73;
    1140             :             }
    1141        7509 :             group_size = 3 << (s->exp_strategy[blk][ch] - 1);
    1142        7509 :             s->num_exp_groups[ch] = (s->end_freq[ch] + group_size-4) / group_size;
    1143        7509 :             if (blk > 0 && s->end_freq[ch] != prev)
    1144           4 :                 memset(bit_alloc_stages, 3, AC3_MAX_CHANNELS);
    1145             :         }
    1146             :     }
    1147       11443 :     if (cpl_in_use && s->exp_strategy[blk][CPL_CH] != EXP_REUSE) {
    1148        4234 :         s->num_exp_groups[CPL_CH] = (s->end_freq[CPL_CH] - s->start_freq[CPL_CH]) /
    1149        2117 :                                     (3 << (s->exp_strategy[blk][CPL_CH] - 1));
    1150             :     }
    1151             : 
    1152             :     /* decode exponents for each channel */
    1153       49521 :     for (ch = !cpl_in_use; ch <= s->channels; ch++) {
    1154       38078 :         if (s->exp_strategy[blk][ch] != EXP_REUSE) {
    1155        9958 :             s->dexps[ch][0] = get_bits(gbc, 4) << !ch;
    1156       19916 :             if (decode_exponents(s, gbc, s->exp_strategy[blk][ch],
    1157        9958 :                                  s->num_exp_groups[ch], s->dexps[ch][0],
    1158        9958 :                                  &s->dexps[ch][s->start_freq[ch]+!!ch])) {
    1159           0 :                 return AVERROR_INVALIDDATA;
    1160             :             }
    1161        9958 :             if (ch != CPL_CH && ch != s->lfe_ch)
    1162        7509 :                 skip_bits(gbc, 2); /* skip gainrng */
    1163             :         }
    1164             :     }
    1165             : 
    1166             :     /* bit allocation information */
    1167       11443 :     if (s->bit_allocation_syntax) {
    1168        6583 :         if (get_bits1(gbc)) {
    1169        1205 :             s->bit_alloc_params.slow_decay = ff_ac3_slow_decay_tab[get_bits(gbc, 2)] >> s->bit_alloc_params.sr_shift;
    1170        1205 :             s->bit_alloc_params.fast_decay = ff_ac3_fast_decay_tab[get_bits(gbc, 2)] >> s->bit_alloc_params.sr_shift;
    1171        1205 :             s->bit_alloc_params.slow_gain  = ff_ac3_slow_gain_tab[get_bits(gbc, 2)];
    1172        1205 :             s->bit_alloc_params.db_per_bit = ff_ac3_db_per_bit_tab[get_bits(gbc, 2)];
    1173        1205 :             s->bit_alloc_params.floor  = ff_ac3_floor_tab[get_bits(gbc, 3)];
    1174        6126 :             for (ch = !cpl_in_use; ch <= s->channels; ch++)
    1175        4921 :                 bit_alloc_stages[ch] = FFMAX(bit_alloc_stages[ch], 2);
    1176        5378 :         } else if (!blk) {
    1177           0 :             av_log(s->avctx, AV_LOG_ERROR, "new bit allocation info must "
    1178             :                    "be present in block 0\n");
    1179           0 :             return AVERROR_INVALIDDATA;
    1180             :         }
    1181             :     }
    1182             : 
    1183             :     /* signal-to-noise ratio offsets and fast gains (signal-to-mask ratios) */
    1184       11443 :     if (!s->eac3 || !blk) {
    1185        7706 :         if (s->snr_offset_strategy && get_bits1(gbc)) {
    1186         953 :             int snr = 0;
    1187             :             int csnr;
    1188         953 :             csnr = (get_bits(gbc, 6) - 15) << 4;
    1189        4736 :             for (i = ch = !cpl_in_use; ch <= s->channels; ch++) {
    1190             :                 /* snr offset */
    1191        3783 :                 if (ch == i || s->snr_offset_strategy == 2)
    1192        3783 :                     snr = (csnr + get_bits(gbc, 4)) << 2;
    1193             :                 /* run at least last bit allocation stage if snr offset changes */
    1194        3783 :                 if (blk && s->snr_offset[ch] != snr) {
    1195           0 :                     bit_alloc_stages[ch] = FFMAX(bit_alloc_stages[ch], 1);
    1196             :                 }
    1197        3783 :                 s->snr_offset[ch] = snr;
    1198             : 
    1199             :                 /* fast gain (normal AC-3 only) */
    1200        3783 :                 if (!s->eac3) {
    1201        3783 :                     int prev = s->fast_gain[ch];
    1202        3783 :                     s->fast_gain[ch] = ff_ac3_fast_gain_tab[get_bits(gbc, 3)];
    1203             :                     /* run last 2 bit allocation stages if fast gain changes */
    1204        3783 :                     if (blk && prev != s->fast_gain[ch])
    1205           0 :                         bit_alloc_stages[ch] = FFMAX(bit_alloc_stages[ch], 2);
    1206             :                 }
    1207             :             }
    1208        5800 :         } else if (!s->eac3 && !blk) {
    1209           0 :             av_log(s->avctx, AV_LOG_ERROR, "new snr offsets must be present in block 0\n");
    1210           0 :             return AVERROR_INVALIDDATA;
    1211             :         }
    1212             :     }
    1213             : 
    1214             :     /* fast gain (E-AC-3 only) */
    1215       11443 :     if (s->fast_gain_syntax && get_bits1(gbc)) {
    1216           0 :         for (ch = !cpl_in_use; ch <= s->channels; ch++) {
    1217           0 :             int prev = s->fast_gain[ch];
    1218           0 :             s->fast_gain[ch] = ff_ac3_fast_gain_tab[get_bits(gbc, 3)];
    1219             :             /* run last 2 bit allocation stages if fast gain changes */
    1220           0 :             if (blk && prev != s->fast_gain[ch])
    1221           0 :                 bit_alloc_stages[ch] = FFMAX(bit_alloc_stages[ch], 2);
    1222             :         }
    1223       11443 :     } else if (s->eac3 && !blk) {
    1224        4084 :         for (ch = !cpl_in_use; ch <= s->channels; ch++)
    1225        3049 :             s->fast_gain[ch] = ff_ac3_fast_gain_tab[4];
    1226             :     }
    1227             : 
    1228             :     /* E-AC-3 to AC-3 converter SNR offset */
    1229       11443 :     if (s->frame_type == EAC3_FRAME_TYPE_INDEPENDENT && get_bits1(gbc)) {
    1230         681 :         skip_bits(gbc, 10); // skip converter snr offset
    1231             :     }
    1232             : 
    1233             :     /* coupling leak information */
    1234       11443 :     if (cpl_in_use) {
    1235        7770 :         if (s->first_cpl_leak || get_bits1(gbc)) {
    1236        1150 :             int fl = get_bits(gbc, 3);
    1237        1150 :             int sl = get_bits(gbc, 3);
    1238             :             /* run last 2 bit allocation stages for coupling channel if
    1239             :                coupling leak changes */
    1240        1151 :             if (blk && (fl != s->bit_alloc_params.cpl_fast_leak ||
    1241           1 :                 sl != s->bit_alloc_params.cpl_slow_leak)) {
    1242          46 :                 bit_alloc_stages[CPL_CH] = FFMAX(bit_alloc_stages[CPL_CH], 2);
    1243             :             }
    1244        1150 :             s->bit_alloc_params.cpl_fast_leak = fl;
    1245        1150 :             s->bit_alloc_params.cpl_slow_leak = sl;
    1246        5470 :         } else if (!s->eac3 && !blk) {
    1247           0 :             av_log(s->avctx, AV_LOG_ERROR, "new coupling leak info must "
    1248             :                    "be present in block 0\n");
    1249           0 :             return AVERROR_INVALIDDATA;
    1250             :         }
    1251        6620 :         s->first_cpl_leak = 0;
    1252             :     }
    1253             : 
    1254             :     /* delta bit allocation information */
    1255       11443 :     if (s->dba_syntax && get_bits1(gbc)) {
    1256             :         /* delta bit allocation exists (strategy) */
    1257           0 :         for (ch = !cpl_in_use; ch <= fbw_channels; ch++) {
    1258           0 :             s->dba_mode[ch] = get_bits(gbc, 2);
    1259           0 :             if (s->dba_mode[ch] == DBA_RESERVED) {
    1260           0 :                 av_log(s->avctx, AV_LOG_ERROR, "delta bit allocation strategy reserved\n");
    1261           0 :                 return AVERROR_INVALIDDATA;
    1262             :             }
    1263           0 :             bit_alloc_stages[ch] = FFMAX(bit_alloc_stages[ch], 2);
    1264             :         }
    1265             :         /* channel delta offset, len and bit allocation */
    1266           0 :         for (ch = !cpl_in_use; ch <= fbw_channels; ch++) {
    1267           0 :             if (s->dba_mode[ch] == DBA_NEW) {
    1268           0 :                 s->dba_nsegs[ch] = get_bits(gbc, 3) + 1;
    1269           0 :                 for (seg = 0; seg < s->dba_nsegs[ch]; seg++) {
    1270           0 :                     s->dba_offsets[ch][seg] = get_bits(gbc, 5);
    1271           0 :                     s->dba_lengths[ch][seg] = get_bits(gbc, 4);
    1272           0 :                     s->dba_values[ch][seg]  = get_bits(gbc, 3);
    1273             :                 }
    1274             :                 /* run last 2 bit allocation stages if new dba values */
    1275           0 :                 bit_alloc_stages[ch] = FFMAX(bit_alloc_stages[ch], 2);
    1276             :             }
    1277             :         }
    1278       11443 :     } else if (blk == 0) {
    1279        9704 :         for (ch = 0; ch <= s->channels; ch++) {
    1280        7716 :             s->dba_mode[ch] = DBA_NONE;
    1281             :         }
    1282             :     }
    1283             : 
    1284             :     /* Bit allocation */
    1285       49521 :     for (ch = !cpl_in_use; ch <= s->channels; ch++) {
    1286       38078 :         if (bit_alloc_stages[ch] > 2) {
    1287             :             /* Exponent mapping into PSD and PSD integration */
    1288        9958 :             ff_ac3_bit_alloc_calc_psd(s->dexps[ch],
    1289             :                                       s->start_freq[ch], s->end_freq[ch],
    1290        9958 :                                       s->psd[ch], s->band_psd[ch]);
    1291             :         }
    1292       38078 :         if (bit_alloc_stages[ch] > 1) {
    1293             :             /* Compute excitation function, Compute masking curve, and
    1294             :                Apply delta bit allocation */
    1295       20120 :             if (ff_ac3_bit_alloc_calc_mask(&s->bit_alloc_params, s->band_psd[ch],
    1296             :                                            s->start_freq[ch],  s->end_freq[ch],
    1297       10060 :                                            s->fast_gain[ch],   (ch == s->lfe_ch),
    1298             :                                            s->dba_mode[ch],    s->dba_nsegs[ch],
    1299       10060 :                                            s->dba_offsets[ch], s->dba_lengths[ch],
    1300       10060 :                                            s->dba_values[ch],  s->mask[ch])) {
    1301           0 :                 av_log(s->avctx, AV_LOG_ERROR, "error in bit allocation\n");
    1302           0 :                 return AVERROR_INVALIDDATA;
    1303             :             }
    1304             :         }
    1305       38078 :         if (bit_alloc_stages[ch] > 0) {
    1306             :             /* Compute bit allocation */
    1307       20120 :             const uint8_t *bap_tab = s->channel_uses_aht[ch] ?
    1308       10060 :                                      ff_eac3_hebap_tab : ff_ac3_bap_tab;
    1309       20120 :             s->ac3dsp.bit_alloc_calc_bap(s->mask[ch], s->psd[ch],
    1310             :                                       s->start_freq[ch], s->end_freq[ch],
    1311             :                                       s->snr_offset[ch],
    1312             :                                       s->bit_alloc_params.floor,
    1313       10060 :                                       bap_tab, s->bap[ch]);
    1314             :         }
    1315             :     }
    1316             : 
    1317             :     /* unused dummy data */
    1318       11443 :     if (s->skip_syntax && get_bits1(gbc)) {
    1319         734 :         int skipl = get_bits(gbc, 9);
    1320       12973 :         while (skipl--)
    1321       11505 :             skip_bits(gbc, 8);
    1322             :     }
    1323             : 
    1324             :     /* unpack the transform coefficients
    1325             :        this also uncouples channels if coupling is in use. */
    1326       11443 :     decode_transform_coeffs(s, blk);
    1327             : 
    1328             :     /* TODO: generate enhanced coupling coordinates and uncouple */
    1329             : 
    1330             :     /* recover coefficients if rematrixing is in use */
    1331       11443 :     if (s->channel_mode == AC3_CHMODE_STEREO)
    1332        8544 :         do_rematrixing(s);
    1333             : 
    1334             :     /* apply scaling to coefficients (headroom, dynrng) */
    1335       42901 :     for (ch = 1; ch <= s->channels; ch++) {
    1336       31458 :         int audio_channel = 0;
    1337             :         INTFLOAT gain;
    1338       31458 :         if (s->channel_mode == AC3_CHMODE_DUALMONO)
    1339           0 :             audio_channel = 2-ch;
    1340       31458 :         if (s->heavy_compression && s->compression_exists[audio_channel])
    1341           0 :             gain = s->heavy_dynamic_range[audio_channel];
    1342             :         else
    1343       31458 :             gain = s->dynamic_range[audio_channel];
    1344             : 
    1345             : #if USE_FIXED
    1346        3048 :         scale_coefs(s->transform_coeffs[ch], s->fixed_coeffs[ch], gain, 256);
    1347             : #else
    1348       28410 :         if (s->target_level != 0)
    1349           0 :           gain = gain * s->level_gain[audio_channel];
    1350       28410 :         gain *= 1.0 / 4194304.0f;
    1351       56820 :         s->fmt_conv.int32_to_float_fmul_scalar(s->transform_coeffs[ch],
    1352       28410 :                                                s->fixed_coeffs[ch], gain, 256);
    1353             : #endif
    1354             :     }
    1355             : 
    1356             :     /* apply spectral extension to high frequency bins */
    1357       11443 :     if (CONFIG_EAC3_DECODER && s->spx_in_use) {
    1358        3210 :         ff_eac3_apply_spectral_extension(s);
    1359             :     }
    1360             : 
    1361             :     /* downmix and MDCT. order depends on whether block switching is used for
    1362             :        any channel in this block. this is because coefficients for the long
    1363             :        and short transforms cannot be mixed. */
    1364       15055 :     downmix_output = s->channels != s->out_channels &&
    1365        1806 :                      !((s->output_mode & AC3_OUTPUT_LFEON) &&
    1366           0 :                      s->fbw_channels == s->out_channels);
    1367       11443 :     if (different_transforms) {
    1368             :         /* the delay samples have already been downmixed, so we upmix the delay
    1369             :            samples in order to reconstruct all channels before downmixing. */
    1370           6 :         if (s->downmixed) {
    1371           6 :             s->downmixed = 0;
    1372           6 :             ac3_upmix_delay(s);
    1373             :         }
    1374             : 
    1375           6 :         do_imdct(s, s->channels);
    1376             : 
    1377           6 :         if (downmix_output) {
    1378             : #if USE_FIXED
    1379           1 :             ac3_downmix_c_fixed16(s->outptr, s->downmix_coeffs,
    1380             :                               s->out_channels, s->fbw_channels, 256);
    1381             : #else
    1382           2 :             s->ac3dsp.downmix(s->outptr, s->downmix_coeffs,
    1383             :                               s->out_channels, s->fbw_channels, 256);
    1384             : #endif
    1385             :         }
    1386             :     } else {
    1387       11437 :         if (downmix_output) {
    1388        1803 :             s->ac3dsp.AC3_RENAME(downmix)(s->xcfptr + 1, s->downmix_coeffs,
    1389             :                                           s->out_channels, s->fbw_channels, 256);
    1390             :         }
    1391             : 
    1392       11437 :         if (downmix_output && !s->downmixed) {
    1393           3 :             s->downmixed = 1;
    1394           3 :             s->ac3dsp.AC3_RENAME(downmix)(s->dlyptr, s->downmix_coeffs,
    1395             :                                           s->out_channels, s->fbw_channels, 128);
    1396             :         }
    1397             : 
    1398       11437 :         do_imdct(s, s->out_channels);
    1399             :     }
    1400             : 
    1401       11443 :     return 0;
    1402             : }
    1403             : 
    1404             : /**
    1405             :  * Decode a single AC-3 frame.
    1406             :  */
    1407        1993 : static int ac3_decode_frame(AVCodecContext * avctx, void *data,
    1408             :                             int *got_frame_ptr, AVPacket *avpkt)
    1409             : {
    1410        1993 :     AVFrame *frame     = data;
    1411        1993 :     const uint8_t *buf = avpkt->data;
    1412        1993 :     int buf_size = avpkt->size;
    1413        1993 :     AC3DecodeContext *s = avctx->priv_data;
    1414             :     int blk, ch, err, ret;
    1415             :     const uint8_t *channel_map;
    1416             :     const SHORTFLOAT *output[AC3_MAX_CHANNELS];
    1417             :     enum AVMatrixEncoding matrix_encoding;
    1418             :     AVDownmixInfo *downmix_info;
    1419             : 
    1420             :     /* copy input buffer to decoder context to avoid reading past the end
    1421             :        of the buffer, which can be caused by a damaged input stream. */
    1422        1993 :     if (buf_size >= 2 && AV_RB16(buf) == 0x770B) {
    1423             :         // seems to be byte-swapped AC-3
    1424           0 :         int cnt = FFMIN(buf_size, AC3_FRAME_BUFFER_SIZE) >> 1;
    1425           0 :         s->bdsp.bswap16_buf((uint16_t *) s->input_buffer,
    1426             :                             (const uint16_t *) buf, cnt);
    1427             :     } else
    1428        1993 :         memcpy(s->input_buffer, buf, FFMIN(buf_size, AC3_FRAME_BUFFER_SIZE));
    1429             : 
    1430             :     /* if consistent noise generation is enabled, seed the linear feedback generator
    1431             :      * with the contents of the AC-3 frame so that the noise is identical across
    1432             :      * decodes given the same AC-3 frame data, for use with non-linear edititing software. */
    1433        1993 :     if (s->consistent_noise_generation)
    1434           0 :         av_lfg_init_from_data(&s->dith_state, s->input_buffer, FFMIN(buf_size, AC3_FRAME_BUFFER_SIZE));
    1435             : 
    1436        1993 :     buf = s->input_buffer;
    1437             :     /* initialize the GetBitContext with the start of valid AC-3 Frame */
    1438        1993 :     if ((ret = init_get_bits8(&s->gbc, buf, buf_size)) < 0)
    1439           0 :         return ret;
    1440             : 
    1441             :     /* parse the syncinfo */
    1442        1993 :     err = parse_frame_header(s);
    1443             : 
    1444        1993 :     if (err) {
    1445           0 :         switch (err) {
    1446             :         case AAC_AC3_PARSE_ERROR_SYNC:
    1447           0 :             av_log(avctx, AV_LOG_ERROR, "frame sync error\n");
    1448           0 :             return AVERROR_INVALIDDATA;
    1449             :         case AAC_AC3_PARSE_ERROR_BSID:
    1450           0 :             av_log(avctx, AV_LOG_ERROR, "invalid bitstream id\n");
    1451           0 :             break;
    1452             :         case AAC_AC3_PARSE_ERROR_SAMPLE_RATE:
    1453           0 :             av_log(avctx, AV_LOG_ERROR, "invalid sample rate\n");
    1454           0 :             break;
    1455             :         case AAC_AC3_PARSE_ERROR_FRAME_SIZE:
    1456           0 :             av_log(avctx, AV_LOG_ERROR, "invalid frame size\n");
    1457           0 :             break;
    1458             :         case AAC_AC3_PARSE_ERROR_FRAME_TYPE:
    1459             :             /* skip frame if CRC is ok. otherwise use error concealment. */
    1460             :             /* TODO: add support for substreams and dependent frames */
    1461           0 :             if (s->frame_type == EAC3_FRAME_TYPE_DEPENDENT || s->substreamid) {
    1462           0 :                 av_log(avctx, AV_LOG_DEBUG,
    1463             :                        "unsupported frame type %d: skipping frame\n",
    1464             :                        s->frame_type);
    1465           0 :                 *got_frame_ptr = 0;
    1466           0 :                 return buf_size;
    1467             :             } else {
    1468           0 :                 av_log(avctx, AV_LOG_ERROR, "invalid frame type\n");
    1469             :             }
    1470           0 :             break;
    1471             :         case AAC_AC3_PARSE_ERROR_CRC:
    1472             :         case AAC_AC3_PARSE_ERROR_CHANNEL_CFG:
    1473           0 :             break;
    1474             :         default: // Normal AVERROR do not try to recover.
    1475           0 :             *got_frame_ptr = 0;
    1476           0 :             return err;
    1477             :         }
    1478             :     } else {
    1479             :         /* check that reported frame size fits in input buffer */
    1480        1993 :         if (s->frame_size > buf_size) {
    1481           5 :             av_log(avctx, AV_LOG_ERROR, "incomplete frame\n");
    1482           5 :             err = AAC_AC3_PARSE_ERROR_FRAME_SIZE;
    1483        1988 :         } else if (avctx->err_recognition & (AV_EF_CRCCHECK|AV_EF_CAREFUL)) {
    1484             :             /* check for crc mismatch */
    1485           0 :             if (av_crc(av_crc_get_table(AV_CRC_16_ANSI), 0, &buf[2],
    1486           0 :                        s->frame_size - 2)) {
    1487           0 :                 av_log(avctx, AV_LOG_ERROR, "frame CRC mismatch\n");
    1488           0 :                 if (avctx->err_recognition & AV_EF_EXPLODE)
    1489           0 :                     return AVERROR_INVALIDDATA;
    1490           0 :                 err = AAC_AC3_PARSE_ERROR_CRC;
    1491             :             }
    1492             :         }
    1493             :     }
    1494             : 
    1495             :     /* if frame is ok, set audio parameters */
    1496        1993 :     if (!err) {
    1497        1988 :         avctx->sample_rate = s->sample_rate;
    1498        1988 :         avctx->bit_rate    = s->bit_rate;
    1499             :     }
    1500             : 
    1501             :     /* channel config */
    1502        1993 :     if (!err || (s->channels && s->out_channels != s->channels)) {
    1503        1990 :         s->out_channels = s->channels;
    1504        1990 :         s->output_mode  = s->channel_mode;
    1505        1990 :         if (s->lfe_on)
    1506         314 :             s->output_mode |= AC3_OUTPUT_LFEON;
    1507        3980 :         if (s->channels > 1 &&
    1508        1990 :             avctx->request_channel_layout == AV_CH_LAYOUT_MONO) {
    1509         183 :             s->out_channels = 1;
    1510         183 :             s->output_mode  = AC3_CHMODE_MONO;
    1511        2190 :         } else if (s->channels > 2 &&
    1512         383 :                    avctx->request_channel_layout == AV_CH_LAYOUT_STEREO) {
    1513         120 :             s->out_channels = 2;
    1514         120 :             s->output_mode  = AC3_CHMODE_STEREO;
    1515             :         }
    1516             : 
    1517        1990 :         s->loro_center_mix_level   = gain_levels[s->  center_mix_level];
    1518        1990 :         s->loro_surround_mix_level = gain_levels[s->surround_mix_level];
    1519        1990 :         s->ltrt_center_mix_level   = LEVEL_MINUS_3DB;
    1520        1990 :         s->ltrt_surround_mix_level = LEVEL_MINUS_3DB;
    1521             :         /* set downmixing coefficients if needed */
    1522        3980 :         if (s->channels != s->out_channels && !((s->output_mode & AC3_OUTPUT_LFEON) &&
    1523           0 :                 s->fbw_channels == s->out_channels)) {
    1524         303 :             set_downmix_coeffs(s);
    1525             :         }
    1526           3 :     } else if (!s->channels) {
    1527           0 :         av_log(avctx, AV_LOG_ERROR, "unable to determine channel mode\n");
    1528           0 :         return AVERROR_INVALIDDATA;
    1529             :     }
    1530        1993 :     avctx->channels = s->out_channels;
    1531        1993 :     avctx->channel_layout = avpriv_ac3_channel_layout_tab[s->output_mode & ~AC3_OUTPUT_LFEON];
    1532        1993 :     if (s->output_mode & AC3_OUTPUT_LFEON)
    1533         201 :         avctx->channel_layout |= AV_CH_LOW_FREQUENCY;
    1534             : 
    1535             :     /* set audio service type based on bitstream mode for AC-3 */
    1536        1993 :     avctx->audio_service_type = s->bitstream_mode;
    1537        1993 :     if (s->bitstream_mode == 0x7 && s->channels > 1)
    1538           0 :         avctx->audio_service_type = AV_AUDIO_SERVICE_TYPE_KARAOKE;
    1539             : 
    1540             :     /* get output buffer */
    1541        1993 :     frame->nb_samples = s->num_blocks * AC3_BLOCK_SIZE;
    1542        1993 :     if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
    1543           0 :         return ret;
    1544             : 
    1545             :     /* decode the audio blocks */
    1546        1993 :     channel_map = ff_ac3_dec_channel_map[s->output_mode & ~AC3_OUTPUT_LFEON][s->lfe_on];
    1547       15944 :     for (ch = 0; ch < AC3_MAX_CHANNELS; ch++) {
    1548       13951 :         output[ch] = s->output[ch];
    1549       13951 :         s->outptr[ch] = s->output[ch];
    1550             :     }
    1551        7743 :     for (ch = 0; ch < s->channels; ch++) {
    1552        5750 :         if (ch < s->out_channels)
    1553        4733 :             s->outptr[channel_map[ch]] = (SHORTFLOAT *)frame->data[ch];
    1554             :     }
    1555       13466 :     for (blk = 0; blk < s->num_blocks; blk++) {
    1556       11473 :         if (!err && decode_audio_block(s, blk)) {
    1557           0 :             av_log(avctx, AV_LOG_ERROR, "error decoding the audio block\n");
    1558           0 :             err = 1;
    1559             :         }
    1560       11473 :         if (err)
    1561         108 :             for (ch = 0; ch < s->out_channels; ch++)
    1562          78 :                 memcpy(((SHORTFLOAT*)frame->data[ch]) + AC3_BLOCK_SIZE*blk, output[ch], AC3_BLOCK_SIZE*sizeof(SHORTFLOAT));
    1563       36961 :         for (ch = 0; ch < s->out_channels; ch++)
    1564       25488 :             output[ch] = s->outptr[channel_map[ch]];
    1565       36961 :         for (ch = 0; ch < s->out_channels; ch++) {
    1566       25488 :             if (!ch || channel_map[ch])
    1567       25488 :                 s->outptr[channel_map[ch]] += AC3_BLOCK_SIZE;
    1568             :         }
    1569             :     }
    1570             : 
    1571        1993 :     av_frame_set_decode_error_flags(frame, err ? FF_DECODE_ERROR_INVALID_BITSTREAM : 0);
    1572             : 
    1573             :     /* keep last block for error concealment in next frame */
    1574        6726 :     for (ch = 0; ch < s->out_channels; ch++)
    1575        4733 :         memcpy(s->output[ch], output[ch], AC3_BLOCK_SIZE*sizeof(SHORTFLOAT));
    1576             : 
    1577             :     /*
    1578             :      * AVMatrixEncoding
    1579             :      *
    1580             :      * Check whether the input layout is compatible, and make sure we're not
    1581             :      * downmixing (else the matrix encoding is no longer applicable).
    1582             :      */
    1583        1993 :     matrix_encoding = AV_MATRIX_ENCODING_NONE;
    1584        3419 :     if (s->channel_mode == AC3_CHMODE_STEREO &&
    1585        1426 :         s->channel_mode == (s->output_mode & ~AC3_OUTPUT_LFEON)) {
    1586        2852 :         if (s->dolby_surround_mode == AC3_DSURMOD_ON)
    1587         488 :             matrix_encoding = AV_MATRIX_ENCODING_DOLBY;
    1588         938 :         else if (s->dolby_headphone_mode == AC3_DHEADPHONMOD_ON)
    1589           0 :             matrix_encoding = AV_MATRIX_ENCODING_DOLBYHEADPHONE;
    1590         882 :     } else if (s->channel_mode >= AC3_CHMODE_2F2R &&
    1591         315 :                s->channel_mode == (s->output_mode & ~AC3_OUTPUT_LFEON)) {
    1592         201 :         switch (s->dolby_surround_ex_mode) {
    1593             :         case AC3_DSUREXMOD_ON: // EX or PLIIx
    1594           0 :             matrix_encoding = AV_MATRIX_ENCODING_DOLBYEX;
    1595           0 :             break;
    1596             :         case AC3_DSUREXMOD_PLIIZ:
    1597           0 :             matrix_encoding = AV_MATRIX_ENCODING_DPLIIZ;
    1598           0 :             break;
    1599             :         default: // not indicated or off
    1600         201 :             break;
    1601             :         }
    1602             :     }
    1603        1993 :     if ((ret = ff_side_data_update_matrix_encoding(frame, matrix_encoding)) < 0)
    1604           0 :         return ret;
    1605             : 
    1606             :     /* AVDownmixInfo */
    1607        1993 :     if ((downmix_info = av_downmix_info_update_side_data(frame))) {
    1608        1993 :         switch (s->preferred_downmix) {
    1609             :         case AC3_DMIXMOD_LTRT:
    1610          47 :             downmix_info->preferred_downmix_type = AV_DOWNMIX_TYPE_LTRT;
    1611          47 :             break;
    1612             :         case AC3_DMIXMOD_LORO:
    1613           0 :             downmix_info->preferred_downmix_type = AV_DOWNMIX_TYPE_LORO;
    1614           0 :             break;
    1615             :         case AC3_DMIXMOD_DPLII:
    1616          97 :             downmix_info->preferred_downmix_type = AV_DOWNMIX_TYPE_DPLII;
    1617          97 :             break;
    1618             :         default:
    1619        1849 :             downmix_info->preferred_downmix_type = AV_DOWNMIX_TYPE_UNKNOWN;
    1620        1849 :             break;
    1621             :         }
    1622        1993 :         downmix_info->center_mix_level        = gain_levels[s->       center_mix_level];
    1623        1993 :         downmix_info->center_mix_level_ltrt   = gain_levels[s->  center_mix_level_ltrt];
    1624        1993 :         downmix_info->surround_mix_level      = gain_levels[s->     surround_mix_level];
    1625        1993 :         downmix_info->surround_mix_level_ltrt = gain_levels[s->surround_mix_level_ltrt];
    1626        1993 :         if (s->lfe_mix_level_exists)
    1627         144 :             downmix_info->lfe_mix_level       = gain_levels_lfe[s->lfe_mix_level];
    1628             :         else
    1629        1849 :             downmix_info->lfe_mix_level       = 0.0; // -inf dB
    1630             :     } else
    1631           0 :         return AVERROR(ENOMEM);
    1632             : 
    1633        1993 :     *got_frame_ptr = 1;
    1634             : 
    1635        1993 :     return FFMIN(buf_size, s->frame_size);
    1636             : }
    1637             : 
    1638             : /**
    1639             :  * Uninitialize the AC-3 decoder.
    1640             :  */
    1641          36 : static av_cold int ac3_decode_end(AVCodecContext *avctx)
    1642             : {
    1643          36 :     AC3DecodeContext *s = avctx->priv_data;
    1644          36 :     ff_mdct_end(&s->imdct_512);
    1645          36 :     ff_mdct_end(&s->imdct_256);
    1646          36 :     av_freep(&s->fdsp);
    1647             : 
    1648          36 :     return 0;
    1649             : }
    1650             : 
    1651             : #define OFFSET(x) offsetof(AC3DecodeContext, x)
    1652             : #define PAR (AV_OPT_FLAG_DECODING_PARAM | AV_OPT_FLAG_AUDIO_PARAM)

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