LCOV - code coverage report
Current view: top level - src/libavcodec - ac3_parser.c (source / functions) Hit Total Coverage
Test: coverage.info Lines: 94 96 97.9 %
Date: 2017-09-22 00:04:37 Functions: 3 3 100.0 %

          Line data    Source code
       1             : /*
       2             :  * AC-3 parser
       3             :  * Copyright (c) 2003 Fabrice Bellard
       4             :  * Copyright (c) 2003 Michael Niedermayer
       5             :  *
       6             :  * This file is part of FFmpeg.
       7             :  *
       8             :  * FFmpeg is free software; you can redistribute it and/or
       9             :  * modify it under the terms of the GNU Lesser General Public
      10             :  * License as published by the Free Software Foundation; either
      11             :  * version 2.1 of the License, or (at your option) any later version.
      12             :  *
      13             :  * FFmpeg is distributed in the hope that it will be useful,
      14             :  * but WITHOUT ANY WARRANTY; without even the implied warranty of
      15             :  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      16             :  * Lesser General Public License for more details.
      17             :  *
      18             :  * You should have received a copy of the GNU Lesser General Public
      19             :  * License along with FFmpeg; if not, write to the Free Software
      20             :  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
      21             :  */
      22             : 
      23             : #include "libavutil/channel_layout.h"
      24             : #include "parser.h"
      25             : #include "ac3_parser.h"
      26             : #include "aac_ac3_parser.h"
      27             : #include "get_bits.h"
      28             : 
      29             : 
      30             : #define AC3_HEADER_SIZE 7
      31             : 
      32             : 
      33             : static const uint8_t eac3_blocks[4] = {
      34             :     1, 2, 3, 6
      35             : };
      36             : 
      37             : /**
      38             :  * Table for center mix levels
      39             :  * reference: Section 5.4.2.4 cmixlev
      40             :  */
      41             : static const uint8_t center_levels[4] = { 4, 5, 6, 5 };
      42             : 
      43             : /**
      44             :  * Table for surround mix levels
      45             :  * reference: Section 5.4.2.5 surmixlev
      46             :  */
      47             : static const uint8_t surround_levels[4] = { 4, 6, 7, 6 };
      48             : 
      49             : 
      50       49881 : int avpriv_ac3_parse_header(GetBitContext *gbc, AC3HeaderInfo **phdr)
      51             : {
      52             :     int frame_size_code;
      53             :     AC3HeaderInfo *hdr;
      54             : 
      55       49881 :     if (!*phdr)
      56       12068 :         *phdr = av_mallocz(sizeof(AC3HeaderInfo));
      57       49881 :     if (!*phdr)
      58           0 :         return AVERROR(ENOMEM);
      59       49881 :     hdr = *phdr;
      60             : 
      61       49881 :     memset(hdr, 0, sizeof(*hdr));
      62             : 
      63       49881 :     hdr->sync_word = get_bits(gbc, 16);
      64       49881 :     if(hdr->sync_word != 0x0B77)
      65       33385 :         return AAC_AC3_PARSE_ERROR_SYNC;
      66             : 
      67             :     /* read ahead to bsid to distinguish between AC-3 and E-AC-3 */
      68       16496 :     hdr->bitstream_id = show_bits_long(gbc, 29) & 0x1F;
      69       16496 :     if(hdr->bitstream_id > 16)
      70        2564 :         return AAC_AC3_PARSE_ERROR_BSID;
      71             : 
      72       13932 :     hdr->num_blocks = 6;
      73             : 
      74             :     /* set default mix levels */
      75       13932 :     hdr->center_mix_level   = 5;  // -4.5dB
      76       13932 :     hdr->surround_mix_level = 6;  // -6.0dB
      77             : 
      78             :     /* set default dolby surround mode */
      79       13932 :     hdr->dolby_surround_mode = AC3_DSURMOD_NOTINDICATED;
      80             : 
      81       13932 :     if(hdr->bitstream_id <= 10) {
      82             :         /* Normal AC-3 */
      83        6595 :         hdr->crc1 = get_bits(gbc, 16);
      84        6595 :         hdr->sr_code = get_bits(gbc, 2);
      85        6595 :         if(hdr->sr_code == 3)
      86         156 :             return AAC_AC3_PARSE_ERROR_SAMPLE_RATE;
      87             : 
      88        6439 :         frame_size_code = get_bits(gbc, 6);
      89        6439 :         if(frame_size_code > 37)
      90         180 :             return AAC_AC3_PARSE_ERROR_FRAME_SIZE;
      91             : 
      92        6259 :         skip_bits(gbc, 5); // skip bsid, already got it
      93             : 
      94        6259 :         hdr->bitstream_mode = get_bits(gbc, 3);
      95        6259 :         hdr->channel_mode = get_bits(gbc, 3);
      96             : 
      97        6259 :         if(hdr->channel_mode == AC3_CHMODE_STEREO) {
      98        1651 :             hdr->dolby_surround_mode = get_bits(gbc, 2);
      99             :         } else {
     100        4608 :             if((hdr->channel_mode & 1) && hdr->channel_mode != AC3_CHMODE_MONO)
     101        3179 :                 hdr->  center_mix_level =   center_levels[get_bits(gbc, 2)];
     102        4608 :             if(hdr->channel_mode & 4)
     103        3209 :                 hdr->surround_mix_level = surround_levels[get_bits(gbc, 2)];
     104             :         }
     105        6259 :         hdr->lfe_on = get_bits1(gbc);
     106             : 
     107        6259 :         hdr->sr_shift = FFMAX(hdr->bitstream_id, 8) - 8;
     108        6259 :         hdr->sample_rate = ff_ac3_sample_rate_tab[hdr->sr_code] >> hdr->sr_shift;
     109        6259 :         hdr->bit_rate = (ff_ac3_bitrate_tab[frame_size_code>>1] * 1000) >> hdr->sr_shift;
     110        6259 :         hdr->channels = ff_ac3_channels_tab[hdr->channel_mode] + hdr->lfe_on;
     111        6259 :         hdr->frame_size = ff_ac3_frame_size_tab[frame_size_code][hdr->sr_code] * 2;
     112        6259 :         hdr->frame_type = EAC3_FRAME_TYPE_AC3_CONVERT; //EAC3_FRAME_TYPE_INDEPENDENT;
     113        6259 :         hdr->substreamid = 0;
     114             :     } else {
     115             :         /* Enhanced AC-3 */
     116        7337 :         hdr->crc1 = 0;
     117        7337 :         hdr->frame_type = get_bits(gbc, 2);
     118        7337 :         if(hdr->frame_type == EAC3_FRAME_TYPE_RESERVED)
     119          74 :             return AAC_AC3_PARSE_ERROR_FRAME_TYPE;
     120             : 
     121        7263 :         hdr->substreamid = get_bits(gbc, 3);
     122             : 
     123        7263 :         hdr->frame_size = (get_bits(gbc, 11) + 1) << 1;
     124        7263 :         if(hdr->frame_size < AC3_HEADER_SIZE)
     125           2 :             return AAC_AC3_PARSE_ERROR_FRAME_SIZE;
     126             : 
     127        7261 :         hdr->sr_code = get_bits(gbc, 2);
     128        7261 :         if (hdr->sr_code == 3) {
     129          78 :             int sr_code2 = get_bits(gbc, 2);
     130          78 :             if(sr_code2 == 3)
     131          24 :                 return AAC_AC3_PARSE_ERROR_SAMPLE_RATE;
     132          54 :             hdr->sample_rate = ff_ac3_sample_rate_tab[sr_code2] / 2;
     133          54 :             hdr->sr_shift = 1;
     134             :         } else {
     135        7183 :             hdr->num_blocks = eac3_blocks[get_bits(gbc, 2)];
     136        7183 :             hdr->sample_rate = ff_ac3_sample_rate_tab[hdr->sr_code];
     137        7183 :             hdr->sr_shift = 0;
     138             :         }
     139             : 
     140        7237 :         hdr->channel_mode = get_bits(gbc, 3);
     141        7237 :         hdr->lfe_on = get_bits1(gbc);
     142             : 
     143       14474 :         hdr->bit_rate = 8LL * hdr->frame_size * hdr->sample_rate /
     144        7237 :                         (hdr->num_blocks * 256);
     145        7237 :         hdr->channels = ff_ac3_channels_tab[hdr->channel_mode] + hdr->lfe_on;
     146             :     }
     147       13496 :     hdr->channel_layout = avpriv_ac3_channel_layout_tab[hdr->channel_mode];
     148       13496 :     if (hdr->lfe_on)
     149        4263 :         hdr->channel_layout |= AV_CH_LOW_FREQUENCY;
     150             : 
     151       13496 :     return 0;
     152             : }
     153             : 
     154       24950 : static int ac3_sync(uint64_t state, AACAC3ParseContext *hdr_info,
     155             :         int *need_next_header, int *new_frame_start)
     156             : {
     157             :     int err;
     158             :     union {
     159             :         uint64_t u64;
     160             :         uint8_t  u8[8 + AV_INPUT_BUFFER_PADDING_SIZE];
     161       24950 :     } tmp = { av_be2ne64(state) };
     162       24950 :     AC3HeaderInfo hdr, *phdr = &hdr;
     163             :     GetBitContext gbc;
     164             : 
     165       24950 :     init_get_bits(&gbc, tmp.u8+8-AC3_HEADER_SIZE, 54);
     166       24950 :     err = avpriv_ac3_parse_header(&gbc, &phdr);
     167             : 
     168       24950 :     if(err < 0)
     169       21436 :         return 0;
     170             : 
     171        3514 :     hdr_info->sample_rate = hdr.sample_rate;
     172        3514 :     hdr_info->bit_rate = hdr.bit_rate;
     173        3514 :     hdr_info->channels = hdr.channels;
     174        3514 :     hdr_info->channel_layout = hdr.channel_layout;
     175        3514 :     hdr_info->samples = hdr.num_blocks * 256;
     176        3514 :     hdr_info->service_type = hdr.bitstream_mode;
     177        3514 :     if (hdr.bitstream_mode == 0x7 && hdr.channels > 1)
     178           0 :         hdr_info->service_type = AV_AUDIO_SERVICE_TYPE_KARAOKE;
     179        3514 :     if(hdr.bitstream_id>10)
     180        2337 :         hdr_info->codec_id = AV_CODEC_ID_EAC3;
     181        1177 :     else if (hdr_info->codec_id == AV_CODEC_ID_NONE)
     182          26 :         hdr_info->codec_id = AV_CODEC_ID_AC3;
     183             : 
     184        3514 :     *need_next_header = (hdr.frame_type != EAC3_FRAME_TYPE_AC3_CONVERT);
     185        3514 :     *new_frame_start  = (hdr.frame_type != EAC3_FRAME_TYPE_DEPENDENT);
     186        3514 :     return hdr.frame_size;
     187             : }
     188             : 
     189          37 : static av_cold int ac3_parse_init(AVCodecParserContext *s1)
     190             : {
     191          37 :     AACAC3ParseContext *s = s1->priv_data;
     192          37 :     s->header_size = AC3_HEADER_SIZE;
     193          37 :     s->sync = ac3_sync;
     194          37 :     return 0;
     195             : }
     196             : 
     197             : 
     198             : AVCodecParser ff_ac3_parser = {
     199             :     .codec_ids      = { AV_CODEC_ID_AC3, AV_CODEC_ID_EAC3 },
     200             :     .priv_data_size = sizeof(AACAC3ParseContext),
     201             :     .parser_init    = ac3_parse_init,
     202             :     .parser_parse   = ff_aac_ac3_parse,
     203             :     .parser_close   = ff_parse_close,
     204             : };

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