LCOV - code coverage report
Current view: top level - libavformat - mp3dec.c (source / functions) Hit Total Coverage
Test: coverage.info Lines: 257 299 86.0 %
Date: 2018-05-20 11:54:08 Functions: 10 10 100.0 %

          Line data    Source code
       1             : /*
       2             :  * MP3 demuxer
       3             :  * Copyright (c) 2003 Fabrice Bellard
       4             :  *
       5             :  * This file is part of FFmpeg.
       6             :  *
       7             :  * FFmpeg is free software; you can redistribute it and/or
       8             :  * modify it under the terms of the GNU Lesser General Public
       9             :  * License as published by the Free Software Foundation; either
      10             :  * version 2.1 of the License, or (at your option) any later version.
      11             :  *
      12             :  * FFmpeg is distributed in the hope that it will be useful,
      13             :  * but WITHOUT ANY WARRANTY; without even the implied warranty of
      14             :  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      15             :  * Lesser General Public License for more details.
      16             :  *
      17             :  * You should have received a copy of the GNU Lesser General Public
      18             :  * License along with FFmpeg; if not, write to the Free Software
      19             :  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
      20             :  */
      21             : 
      22             : #include "libavutil/opt.h"
      23             : #include "libavutil/avstring.h"
      24             : #include "libavutil/intreadwrite.h"
      25             : #include "libavutil/crc.h"
      26             : #include "libavutil/dict.h"
      27             : #include "libavutil/mathematics.h"
      28             : #include "avformat.h"
      29             : #include "internal.h"
      30             : #include "avio_internal.h"
      31             : #include "id3v2.h"
      32             : #include "id3v1.h"
      33             : #include "replaygain.h"
      34             : 
      35             : #include "libavcodec/avcodec.h"
      36             : #include "libavcodec/mpegaudiodecheader.h"
      37             : 
      38             : #define XING_FLAG_FRAMES 0x01
      39             : #define XING_FLAG_SIZE   0x02
      40             : #define XING_FLAG_TOC    0x04
      41             : #define XING_FLAC_QSCALE 0x08
      42             : 
      43             : #define XING_TOC_COUNT 100
      44             : 
      45             : #define SAME_HEADER_MASK \
      46             :    (0xffe00000 | (3 << 17) | (3 << 10) | (3 << 19))
      47             : 
      48             : typedef struct {
      49             :     AVClass *class;
      50             :     int64_t filesize;
      51             :     int xing_toc;
      52             :     int start_pad;
      53             :     int end_pad;
      54             :     int usetoc;
      55             :     unsigned frames; /* Total number of frames in file */
      56             :     unsigned header_filesize;   /* Total number of bytes in the stream */
      57             :     int is_cbr;
      58             : } MP3DecContext;
      59             : 
      60             : enum CheckRet {
      61             :     CHECK_WRONG_HEADER = -1,
      62             :     CHECK_SEEK_FAILED  = -2,
      63             : };
      64             : 
      65             : static int check(AVIOContext *pb, int64_t pos, uint32_t *header);
      66             : 
      67             : /* mp3 read */
      68             : 
      69        6217 : static int mp3_read_probe(AVProbeData *p)
      70             : {
      71        6217 :     int max_frames, first_frames = 0;
      72        6217 :     int whole_used = 0;
      73             :     int frames, ret;
      74             :     int framesizes, max_framesizes;
      75             :     uint32_t header;
      76             :     const uint8_t *buf, *buf0, *buf2, *end;
      77             : 
      78        6217 :     buf0 = p->buf;
      79        6217 :     end = p->buf + p->buf_size - sizeof(uint32_t);
      80       74734 :     while(buf0 < end && !*buf0)
      81       62300 :         buf0++;
      82             : 
      83        6217 :     max_frames = 0;
      84        6217 :     max_framesizes = 0;
      85        6217 :     buf = buf0;
      86             : 
      87   116286159 :     for(; buf < end; buf= buf2+1) {
      88   116279942 :         buf2 = buf;
      89   116312567 :         for(framesizes = frames = 0; buf2 < end; frames++) {
      90             :             MPADecodeHeader h;
      91             : 
      92   116311933 :             header = AV_RB32(buf2);
      93   116311933 :             ret = avpriv_mpegaudio_decode_header(&h, header);
      94   116311933 :             if (ret != 0)
      95   116279308 :                 break;
      96       32625 :             buf2 += h.frame_size;
      97       32625 :             framesizes += h.frame_size;
      98             :         }
      99   116279942 :         max_frames = FFMAX(max_frames, frames);
     100   116279942 :         max_framesizes = FFMAX(max_framesizes, framesizes);
     101   116279942 :         if(buf == buf0) {
     102        6215 :             first_frames= frames;
     103        6215 :             if (buf2 == end + sizeof(uint32_t))
     104           1 :                 whole_used = 1;
     105             :         }
     106             :     }
     107             :     // keep this in sync with ac3 probe, both need to avoid
     108             :     // issues with MPEG-files!
     109        6217 :     if   (first_frames>=7) return AVPROBE_SCORE_EXTENSION + 1;
     110        6193 :     else if(max_frames>200 && p->buf_size < 2*max_framesizes)return AVPROBE_SCORE_EXTENSION;
     111        6193 :     else if(max_frames>=4 && p->buf_size < 2*max_framesizes) return AVPROBE_SCORE_EXTENSION / 2;
     112        6186 :     else if(ff_id3v2_match(buf0, ID3v2_DEFAULT_MAGIC) && 2*ff_id3v2_tag_len(buf0) >= p->buf_size)
     113           5 :                            return p->buf_size < PROBE_BUF_MAX ? AVPROBE_SCORE_EXTENSION / 4 : AVPROBE_SCORE_EXTENSION - 2;
     114        6181 :     else if(first_frames > 1 && whole_used) return 5;
     115        6181 :     else if(max_frames>=1 && p->buf_size < 10*max_framesizes) return 1;
     116        5007 :     else                   return 0;
     117             : //mpegps_mp3_unrecognized_format.mpg has max_frames=3
     118             : }
     119             : 
     120          10 : static void read_xing_toc(AVFormatContext *s, int64_t filesize, int64_t duration)
     121             : {
     122             :     int i;
     123          10 :     MP3DecContext *mp3 = s->priv_data;
     124          10 :     int fast_seek = s->flags & AVFMT_FLAG_FAST_SEEK;
     125          10 :     int fill_index = (mp3->usetoc || fast_seek) && duration > 0;
     126             : 
     127          10 :     if (!filesize &&
     128           0 :         !(filesize = avio_size(s->pb))) {
     129           0 :         av_log(s, AV_LOG_WARNING, "Cannot determine file size, skipping TOC table.\n");
     130           0 :         fill_index = 0;
     131             :     }
     132             : 
     133        1010 :     for (i = 0; i < XING_TOC_COUNT; i++) {
     134        1000 :         uint8_t b = avio_r8(s->pb);
     135        1000 :         if (fill_index)
     136         100 :             av_add_index_entry(s->streams[0],
     137             :                            av_rescale(b, filesize, 256),
     138             :                            av_rescale(i, duration, XING_TOC_COUNT),
     139             :                            0, 0, AVINDEX_KEYFRAME);
     140             :     }
     141          10 :     if (fill_index)
     142           1 :         mp3->xing_toc = 1;
     143          10 : }
     144             : 
     145          20 : static void mp3_parse_info_tag(AVFormatContext *s, AVStream *st,
     146             :                                MPADecodeHeader *c, uint32_t spf)
     147             : {
     148             : #define LAST_BITS(k, n) ((k) & ((1 << (n)) - 1))
     149             : #define MIDDLE_BITS(k, m, n) LAST_BITS((k) >> (m), ((n) - (m) + 1))
     150             : 
     151             :     uint16_t crc;
     152             :     uint32_t v;
     153             : 
     154             :     char version[10];
     155             : 
     156          20 :     uint32_t peak   = 0;
     157          20 :     int32_t  r_gain = INT32_MIN, a_gain = INT32_MIN;
     158             : 
     159          20 :     MP3DecContext *mp3 = s->priv_data;
     160             :     static const int64_t xing_offtbl[2][2] = {{32, 17}, {17,9}};
     161          20 :     uint64_t fsize = avio_size(s->pb);
     162          20 :     fsize = fsize >= avio_tell(s->pb) ? fsize - avio_tell(s->pb) : 0;
     163             : 
     164             :     /* Check for Xing / Info tag */
     165          20 :     avio_skip(s->pb, xing_offtbl[c->lsf == 1][c->nb_channels == 1]);
     166          20 :     v = avio_rb32(s->pb);
     167          20 :     mp3->is_cbr = v == MKBETAG('I', 'n', 'f', 'o');
     168          20 :     if (v != MKBETAG('X', 'i', 'n', 'g') && !mp3->is_cbr)
     169           9 :         return;
     170             : 
     171          11 :     v = avio_rb32(s->pb);
     172          11 :     if (v & XING_FLAG_FRAMES)
     173          11 :         mp3->frames = avio_rb32(s->pb);
     174          11 :     if (v & XING_FLAG_SIZE)
     175          10 :         mp3->header_filesize = avio_rb32(s->pb);
     176          11 :     if (fsize && mp3->header_filesize) {
     177             :         uint64_t min, delta;
     178          10 :         min = FFMIN(fsize, mp3->header_filesize);
     179          10 :         delta = FFMAX(fsize, mp3->header_filesize) - min;
     180          10 :         if (fsize > mp3->header_filesize && delta > min >> 4) {
     181           0 :             mp3->frames = 0;
     182           0 :             av_log(s, AV_LOG_WARNING,
     183             :                    "invalid concatenated file detected - using bitrate for duration\n");
     184          10 :         } else if (delta > min >> 4) {
     185           0 :             av_log(s, AV_LOG_WARNING,
     186             :                    "filesize and duration do not match (growing file?)\n");
     187             :         }
     188             :     }
     189          11 :     if (v & XING_FLAG_TOC)
     190          10 :         read_xing_toc(s, mp3->header_filesize, av_rescale_q(mp3->frames,
     191          10 :                                        (AVRational){spf, c->sample_rate},
     192             :                                        st->time_base));
     193             :     /* VBR quality */
     194          11 :     if (v & XING_FLAC_QSCALE)
     195           9 :         avio_rb32(s->pb);
     196             : 
     197             :     /* Encoder short version string */
     198          11 :     memset(version, 0, sizeof(version));
     199          11 :     avio_read(s->pb, version, 9);
     200             : 
     201             :     /* Info Tag revision + VBR method */
     202          11 :     avio_r8(s->pb);
     203             : 
     204             :     /* Lowpass filter value */
     205          11 :     avio_r8(s->pb);
     206             : 
     207             :     /* ReplayGain peak */
     208          11 :     v    = avio_rb32(s->pb);
     209          11 :     peak = av_rescale(v, 100000, 1 << 23);
     210             : 
     211             :     /* Radio ReplayGain */
     212          11 :     v = avio_rb16(s->pb);
     213             : 
     214          11 :     if (MIDDLE_BITS(v, 13, 15) == 1) {
     215           0 :         r_gain = MIDDLE_BITS(v, 0, 8) * 10000;
     216             : 
     217           0 :         if (v & (1 << 9))
     218           0 :             r_gain *= -1;
     219             :     }
     220             : 
     221             :     /* Audiophile ReplayGain */
     222          11 :     v = avio_rb16(s->pb);
     223             : 
     224          11 :     if (MIDDLE_BITS(v, 13, 15) == 2) {
     225           0 :         a_gain = MIDDLE_BITS(v, 0, 8) * 10000;
     226             : 
     227           0 :         if (v & (1 << 9))
     228           0 :             a_gain *= -1;
     229             :     }
     230             : 
     231             :     /* Encoding flags + ATH Type */
     232          11 :     avio_r8(s->pb);
     233             : 
     234             :     /* if ABR {specified bitrate} else {minimal bitrate} */
     235          11 :     avio_r8(s->pb);
     236             : 
     237             :     /* Encoder delays */
     238          11 :     v= avio_rb24(s->pb);
     239          11 :     if(AV_RB32(version) == MKBETAG('L', 'A', 'M', 'E')
     240           3 :         || AV_RB32(version) == MKBETAG('L', 'a', 'v', 'f')
     241           1 :         || AV_RB32(version) == MKBETAG('L', 'a', 'v', 'c')
     242             :     ) {
     243             : 
     244          10 :         mp3->start_pad = v>>12;
     245          10 :         mp3->  end_pad = v&4095;
     246          10 :         st->start_skip_samples = mp3->start_pad + 528 + 1;
     247          10 :         if (mp3->frames) {
     248          10 :             st->first_discard_sample = -mp3->end_pad + 528 + 1 + mp3->frames * (int64_t)spf;
     249          10 :             st->last_discard_sample = mp3->frames * (int64_t)spf;
     250             :         }
     251          10 :         if (!st->start_time)
     252          10 :             st->start_time = av_rescale_q(st->start_skip_samples,
     253          10 :                                             (AVRational){1, c->sample_rate},
     254             :                                             st->time_base);
     255          10 :         av_log(s, AV_LOG_DEBUG, "pad %d %d\n", mp3->start_pad, mp3->  end_pad);
     256             :     }
     257             : 
     258             :     /* Misc */
     259          11 :     avio_r8(s->pb);
     260             : 
     261             :     /* MP3 gain */
     262          11 :     avio_r8(s->pb);
     263             : 
     264             :     /* Preset and surround info */
     265          11 :     avio_rb16(s->pb);
     266             : 
     267             :     /* Music length */
     268          11 :     avio_rb32(s->pb);
     269             : 
     270             :     /* Music CRC */
     271          11 :     avio_rb16(s->pb);
     272             : 
     273             :     /* Info Tag CRC */
     274          11 :     crc = ffio_get_checksum(s->pb);
     275          11 :     v   = avio_rb16(s->pb);
     276             : 
     277          11 :     if (v == crc) {
     278           8 :         ff_replaygain_export_raw(st, r_gain, peak, a_gain, 0);
     279           8 :         av_dict_set(&st->metadata, "encoder", version, 0);
     280             :     }
     281             : }
     282             : 
     283          20 : static void mp3_parse_vbri_tag(AVFormatContext *s, AVStream *st, int64_t base)
     284             : {
     285             :     uint32_t v;
     286          20 :     MP3DecContext *mp3 = s->priv_data;
     287             : 
     288             :     /* Check for VBRI tag (always 32 bytes after end of mpegaudio header) */
     289          20 :     avio_seek(s->pb, base + 4 + 32, SEEK_SET);
     290          20 :     v = avio_rb32(s->pb);
     291          20 :     if (v == MKBETAG('V', 'B', 'R', 'I')) {
     292             :         /* Check tag version */
     293           0 :         if (avio_rb16(s->pb) == 1) {
     294             :             /* skip delay and quality */
     295           0 :             avio_skip(s->pb, 4);
     296           0 :             mp3->header_filesize = avio_rb32(s->pb);
     297           0 :             mp3->frames = avio_rb32(s->pb);
     298             :         }
     299             :     }
     300          20 : }
     301             : 
     302             : /**
     303             :  * Try to find Xing/Info/VBRI tags and compute duration from info therein
     304             :  */
     305          24 : static int mp3_parse_vbr_tags(AVFormatContext *s, AVStream *st, int64_t base)
     306             : {
     307             :     uint32_t v, spf;
     308             :     MPADecodeHeader c;
     309          24 :     int vbrtag_size = 0;
     310          24 :     MP3DecContext *mp3 = s->priv_data;
     311             :     int ret;
     312             : 
     313          24 :     ffio_init_checksum(s->pb, ff_crcA001_update, 0);
     314             : 
     315          24 :     v = avio_rb32(s->pb);
     316             : 
     317          24 :     ret = avpriv_mpegaudio_decode_header(&c, v);
     318          24 :     if (ret < 0)
     319           1 :         return ret;
     320          23 :     else if (ret == 0)
     321          23 :         vbrtag_size = c.frame_size;
     322          23 :     if(c.layer != 3)
     323           3 :         return -1;
     324             : 
     325          20 :     spf = c.lsf ? 576 : 1152; /* Samples per frame, layer 3 */
     326             : 
     327          20 :     mp3->frames = 0;
     328          20 :     mp3->header_filesize   = 0;
     329             : 
     330          20 :     mp3_parse_info_tag(s, st, &c, spf);
     331          20 :     mp3_parse_vbri_tag(s, st, base);
     332             : 
     333          20 :     if (!mp3->frames && !mp3->header_filesize)
     334           9 :         return -1;
     335             : 
     336             :     /* Skip the vbr tag frame */
     337          11 :     avio_seek(s->pb, base + vbrtag_size, SEEK_SET);
     338             : 
     339          11 :     if (mp3->frames)
     340          11 :         st->duration = av_rescale_q(mp3->frames, (AVRational){spf, c.sample_rate},
     341             :                                     st->time_base);
     342          11 :     if (mp3->header_filesize && mp3->frames && !mp3->is_cbr)
     343           1 :         st->codecpar->bit_rate = av_rescale(mp3->header_filesize, 8 * c.sample_rate, mp3->frames * (int64_t)spf);
     344             : 
     345          11 :     return 0;
     346             : }
     347             : 
     348          24 : static int mp3_read_header(AVFormatContext *s)
     349             : {
     350          24 :     MP3DecContext *mp3 = s->priv_data;
     351             :     AVStream *st;
     352             :     int64_t off;
     353             :     int ret;
     354             :     int i;
     355             : 
     356          24 :     s->metadata = s->internal->id3v2_meta;
     357          24 :     s->internal->id3v2_meta = NULL;
     358             : 
     359          24 :     st = avformat_new_stream(s, NULL);
     360          24 :     if (!st)
     361           0 :         return AVERROR(ENOMEM);
     362             : 
     363          24 :     st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
     364          24 :     st->codecpar->codec_id = AV_CODEC_ID_MP3;
     365          24 :     st->need_parsing = AVSTREAM_PARSE_FULL_RAW;
     366          24 :     st->start_time = 0;
     367             : 
     368             :     // lcm of all mp3 sample rates
     369          24 :     avpriv_set_pts_info(st, 64, 1, 14112000);
     370             : 
     371          24 :     s->pb->maxsize = -1;
     372          24 :     off = avio_tell(s->pb);
     373             : 
     374          24 :     if (!av_dict_get(s->metadata, "", NULL, AV_DICT_IGNORE_SUFFIX))
     375          12 :         ff_id3v1_read(s);
     376             : 
     377          24 :     if(s->pb->seekable & AVIO_SEEKABLE_NORMAL)
     378          24 :         mp3->filesize = avio_size(s->pb);
     379             : 
     380          24 :     if (mp3_parse_vbr_tags(s, st, off) < 0)
     381          13 :         avio_seek(s->pb, off, SEEK_SET);
     382             : 
     383          24 :     ret = ff_replaygain_export(st, s->metadata);
     384          24 :     if (ret < 0)
     385           0 :         return ret;
     386             : 
     387          24 :     off = avio_tell(s->pb);
     388        1300 :     for (i = 0; i < 64 * 1024; i++) {
     389             :         uint32_t header, header2;
     390             :         int frame_size;
     391         650 :         if (!(i&1023))
     392          24 :             ffio_ensure_seekback(s->pb, i + 1024 + 4);
     393         650 :         frame_size = check(s->pb, off + i, &header);
     394         650 :         if (frame_size > 0) {
     395          24 :             ret = avio_seek(s->pb, off, SEEK_SET);
     396          24 :             if (ret < 0)
     397           0 :                 return ret;
     398          24 :             ffio_ensure_seekback(s->pb, i + 1024 + frame_size + 4);
     399          24 :             ret = check(s->pb, off + i + frame_size, &header2);
     400          48 :             if (ret >= 0 &&
     401          24 :                 (header & SAME_HEADER_MASK) == (header2 & SAME_HEADER_MASK))
     402             :             {
     403          24 :                 av_log(s, i > 0 ? AV_LOG_INFO : AV_LOG_VERBOSE, "Skipping %d bytes of junk at %"PRId64".\n", i, off);
     404          24 :                 ret = avio_seek(s->pb, off + i, SEEK_SET);
     405          24 :                 if (ret < 0)
     406           0 :                     return ret;
     407          24 :                 break;
     408           0 :             } else if (ret == CHECK_SEEK_FAILED) {
     409           0 :                 av_log(s, AV_LOG_ERROR, "Invalid frame size (%d): Could not seek to %"PRId64".\n", frame_size, off + i + frame_size);
     410           0 :                 return AVERROR(EINVAL);
     411             :             }
     412         626 :         } else if (frame_size == CHECK_SEEK_FAILED) {
     413           0 :             av_log(s, AV_LOG_ERROR, "Failed to read frame size: Could not seek to %"PRId64".\n", (int64_t) (i + 1024 + frame_size + 4));
     414           0 :             return AVERROR(EINVAL);
     415             :         }
     416         626 :         ret = avio_seek(s->pb, off, SEEK_SET);
     417         626 :         if (ret < 0)
     418           0 :             return ret;
     419             :     }
     420             : 
     421             :     // the seek index is relative to the end of the xing vbr headers
     422         124 :     for (i = 0; i < st->nb_index_entries; i++)
     423         100 :         st->index_entries[i].pos += avio_tell(s->pb);
     424             : 
     425             :     /* the parameters will be extracted from the compressed bitstream */
     426          24 :     return 0;
     427             : }
     428             : 
     429             : #define MP3_PACKET_SIZE 1024
     430             : 
     431        2809 : static int mp3_read_packet(AVFormatContext *s, AVPacket *pkt)
     432             : {
     433        2809 :     MP3DecContext *mp3 = s->priv_data;
     434             :     int ret, size;
     435             :     int64_t pos;
     436             : 
     437        2809 :     size= MP3_PACKET_SIZE;
     438        2809 :     pos = avio_tell(s->pb);
     439        2809 :     if(mp3->filesize > ID3v1_TAG_SIZE && pos < mp3->filesize)
     440        2791 :         size= FFMIN(size, mp3->filesize - pos);
     441             : 
     442        2809 :     ret= av_get_packet(s->pb, pkt, size);
     443        2809 :     if (ret <= 0) {
     444          18 :         if(ret<0)
     445          18 :             return ret;
     446           0 :         return AVERROR_EOF;
     447             :     }
     448             : 
     449        2791 :     pkt->flags &= ~AV_PKT_FLAG_CORRUPT;
     450        2791 :     pkt->stream_index = 0;
     451             : 
     452        2791 :     return ret;
     453             : }
     454             : 
     455             : #define SEEK_WINDOW 4096
     456             : 
     457       17648 : static int check(AVIOContext *pb, int64_t pos, uint32_t *ret_header)
     458             : {
     459       17648 :     int64_t ret = avio_seek(pb, pos, SEEK_SET);
     460             :     uint8_t header_buf[4];
     461             :     unsigned header;
     462             :     MPADecodeHeader sd;
     463       17648 :     if (ret < 0)
     464           0 :         return CHECK_SEEK_FAILED;
     465             : 
     466       17648 :     ret = avio_read(pb, &header_buf[0], 4);
     467             :     /* We should always find four bytes for a valid mpa header. */
     468       17648 :     if (ret < 4)
     469           0 :         return CHECK_SEEK_FAILED;
     470             : 
     471       17648 :     header = AV_RB32(&header_buf[0]);
     472       17648 :     if (ff_mpa_check_header(header) < 0)
     473       17424 :         return CHECK_WRONG_HEADER;
     474         224 :     if (avpriv_mpegaudio_decode_header(&sd, header) == 1)
     475           0 :         return CHECK_WRONG_HEADER;
     476             : 
     477         224 :     if (ret_header)
     478          48 :         *ret_header = header;
     479         224 :     return sd.frame_size;
     480             : }
     481             : 
     482          26 : static int64_t mp3_sync(AVFormatContext *s, int64_t target_pos, int flags)
     483             : {
     484          26 :     int dir = (flags&AVSEEK_FLAG_BACKWARD) ? -1 : 1;
     485             :     int64_t best_pos;
     486             :     int best_score, i, j;
     487             :     int64_t ret;
     488             : 
     489          26 :     avio_seek(s->pb, FFMAX(target_pos - SEEK_WINDOW, 0), SEEK_SET);
     490          26 :     ret = avio_seek(s->pb, target_pos, SEEK_SET);
     491          26 :     if (ret < 0)
     492           0 :         return ret;
     493             : 
     494             : #define MIN_VALID 3
     495          26 :     best_pos = target_pos;
     496          26 :     best_score = 999;
     497       16850 :     for(i=0; i<SEEK_WINDOW; i++) {
     498       16850 :         int64_t pos = target_pos + (dir > 0 ? i - SEEK_WINDOW/4 : -i);
     499       16850 :         int64_t candidate = -1;
     500       16850 :         int score = 999;
     501             : 
     502       16850 :         if (pos < 0)
     503           0 :             continue;
     504             : 
     505       17026 :         for(j=0; j<MIN_VALID; j++) {
     506       16974 :             ret = check(s->pb, pos, NULL);
     507       16974 :             if(ret < 0) {
     508       16798 :                 if (ret == CHECK_WRONG_HEADER) {
     509       16798 :                     break;
     510           0 :                 } else if (ret == CHECK_SEEK_FAILED) {
     511           0 :                     av_log(s, AV_LOG_ERROR, "Could not seek to %"PRId64".\n", pos);
     512           0 :                     return AVERROR(EINVAL);
     513             :                 }
     514             :             }
     515         176 :             if ((target_pos - pos)*dir <= 0 && FFABS(MIN_VALID/2-j) < score) {
     516          69 :                 candidate = pos;
     517          69 :                 score = FFABS(MIN_VALID/2-j);
     518             :             }
     519         176 :             pos += ret;
     520             :         }
     521       16850 :         if (best_score > score && j == MIN_VALID) {
     522          48 :             best_pos = candidate;
     523          48 :             best_score = score;
     524          48 :             if(score == 0)
     525          26 :                 break;
     526             :         }
     527             :     }
     528             : 
     529          26 :     return avio_seek(s->pb, best_pos, SEEK_SET);
     530             : }
     531             : 
     532         128 : static int mp3_seek(AVFormatContext *s, int stream_index, int64_t timestamp,
     533             :                     int flags)
     534             : {
     535         128 :     MP3DecContext *mp3 = s->priv_data;
     536             :     AVIndexEntry *ie, ie1;
     537         128 :     AVStream *st = s->streams[0];
     538             :     int64_t best_pos;
     539         128 :     int fast_seek = s->flags & AVFMT_FLAG_FAST_SEEK;
     540         128 :     int64_t filesize = mp3->header_filesize;
     541             : 
     542         128 :     if (filesize <= 0) {
     543          48 :         int64_t size = avio_size(s->pb);
     544          48 :         if (size > 0 && size > s->internal->data_offset)
     545          48 :             filesize = size - s->internal->data_offset;
     546             :     }
     547             : 
     548         128 :     if (mp3->xing_toc && (mp3->usetoc || (fast_seek && !mp3->is_cbr))) {
     549           0 :         int64_t ret = av_index_search_timestamp(st, timestamp, flags);
     550             : 
     551             :         // NOTE: The MP3 TOC is not a precise lookup table. Accuracy is worse
     552             :         // for bigger files.
     553           0 :         av_log(s, AV_LOG_WARNING, "Using MP3 TOC to seek; may be imprecise.\n");
     554             : 
     555           0 :         if (ret < 0)
     556           0 :             return ret;
     557             : 
     558           0 :         ie = &st->index_entries[ret];
     559         128 :     } else if (fast_seek && st->duration > 0 && filesize > 0) {
     560          26 :         if (!mp3->is_cbr)
     561           0 :             av_log(s, AV_LOG_WARNING, "Using scaling to seek VBR MP3; may be imprecise.\n");
     562             : 
     563          26 :         ie = &ie1;
     564          26 :         timestamp = av_clip64(timestamp, 0, st->duration);
     565          26 :         ie->timestamp = timestamp;
     566          26 :         ie->pos       = av_rescale(timestamp, filesize, st->duration) + s->internal->data_offset;
     567             :     } else {
     568         102 :         return -1; // generic index code
     569             :     }
     570             : 
     571          26 :     best_pos = mp3_sync(s, ie->pos, flags);
     572          26 :     if (best_pos < 0)
     573           0 :         return best_pos;
     574             : 
     575          26 :     if (mp3->is_cbr && ie == &ie1 && mp3->frames) {
     576          26 :         int frame_duration = av_rescale(st->duration, 1, mp3->frames);
     577          26 :         ie1.timestamp = frame_duration * av_rescale(best_pos - s->internal->data_offset, mp3->frames, mp3->header_filesize);
     578             :     }
     579             : 
     580          26 :     ff_update_cur_dts(s, st, ie->timestamp);
     581          26 :     return 0;
     582             : }
     583             : 
     584             : static const AVOption options[] = {
     585             :     { "usetoc", "use table of contents", offsetof(MP3DecContext, usetoc), AV_OPT_TYPE_BOOL, {.i64 = 0}, 0, 1, AV_OPT_FLAG_DECODING_PARAM},
     586             :     { NULL },
     587             : };
     588             : 
     589             : static const AVClass demuxer_class = {
     590             :     .class_name = "mp3",
     591             :     .item_name  = av_default_item_name,
     592             :     .option     = options,
     593             :     .version    = LIBAVUTIL_VERSION_INT,
     594             :     .category   = AV_CLASS_CATEGORY_DEMUXER,
     595             : };
     596             : 
     597             : AVInputFormat ff_mp3_demuxer = {
     598             :     .name           = "mp3",
     599             :     .long_name      = NULL_IF_CONFIG_SMALL("MP2/3 (MPEG audio layer 2/3)"),
     600             :     .read_probe     = mp3_read_probe,
     601             :     .read_header    = mp3_read_header,
     602             :     .read_packet    = mp3_read_packet,
     603             :     .read_seek      = mp3_seek,
     604             :     .priv_data_size = sizeof(MP3DecContext),
     605             :     .flags          = AVFMT_GENERIC_INDEX,
     606             :     .extensions     = "mp2,mp3,m2a,mpa", /* XXX: use probe */
     607             :     .priv_class     = &demuxer_class,
     608             : };

Generated by: LCOV version 1.13