libavformat/mp3.c

   1 /*
   2  * MP3 muxer and 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 <strings.h>
  23 #include "libavutil/avstring.h"
  24 #include "libavcodec/mpegaudio.h"
  25 #include "libavcodec/mpegaudiodecheader.h"
  26 #include "avformat.h"
  27
  28 #define ID3v2_HEADER_SIZE 10
  29 #define ID3v1_TAG_SIZE 128
  30
  31 #define ID3v1_GENRE_MAX 125
  32
  33 static const char *id3v1_genre_str[ID3v1_GENRE_MAX + 1] = {
  34     [0] = "Blues",
  35     [1] = "Classic Rock",
  36     [2] = "Country",
  37     [3] = "Dance",
  38     [4] = "Disco",
  39     [5] = "Funk",
  40     [6] = "Grunge",
  41     [7] = "Hip-Hop",
  42     [8] = "Jazz",
  43     [9] = "Metal",
  44     [10] = "New Age",
  45     [11] = "Oldies",
  46     [12] = "Other",
  47     [13] = "Pop",
  48     [14] = "R&B",
  49     [15] = "Rap",
  50     [16] = "Reggae",
  51     [17] = "Rock",
  52     [18] = "Techno",
  53     [19] = "Industrial",
  54     [20] = "Alternative",
  55     [21] = "Ska",
  56     [22] = "Death Metal",
  57     [23] = "Pranks",
  58     [24] = "Soundtrack",
  59     [25] = "Euro-Techno",
  60     [26] = "Ambient",
  61     [27] = "Trip-Hop",
  62     [28] = "Vocal",
  63     [29] = "Jazz+Funk",
  64     [30] = "Fusion",
  65     [31] = "Trance",
  66     [32] = "Classical",
  67     [33] = "Instrumental",
  68     [34] = "Acid",
  69     [35] = "House",
  70     [36] = "Game",
  71     [37] = "Sound Clip",
  72     [38] = "Gospel",
  73     [39] = "Noise",
  74     [40] = "AlternRock",
  75     [41] = "Bass",
  76     [42] = "Soul",
  77     [43] = "Punk",
  78     [44] = "Space",
  79     [45] = "Meditative",
  80     [46] = "Instrumental Pop",
  81     [47] = "Instrumental Rock",
  82     [48] = "Ethnic",
  83     [49] = "Gothic",
  84     [50] = "Darkwave",
  85     [51] = "Techno-Industrial",
  86     [52] = "Electronic",
  87     [53] = "Pop-Folk",
  88     [54] = "Eurodance",
  89     [55] = "Dream",
  90     [56] = "Southern Rock",
  91     [57] = "Comedy",
  92     [58] = "Cult",
  93     [59] = "Gangsta",
  94     [60] = "Top 40",
  95     [61] = "Christian Rap",
  96     [62] = "Pop/Funk",
  97     [63] = "Jungle",
  98     [64] = "Native American",
  99     [65] = "Cabaret",
 100     [66] = "New Wave",
 101     [67] = "Psychadelic",
 102     [68] = "Rave",
 103     [69] = "Showtunes",
 104     [70] = "Trailer",
 105     [71] = "Lo-Fi",
 106     [72] = "Tribal",
 107     [73] = "Acid Punk",
 108     [74] = "Acid Jazz",
 109     [75] = "Polka",
 110     [76] = "Retro",
 111     [77] = "Musical",
 112     [78] = "Rock & Roll",
 113     [79] = "Hard Rock",
 114     [80] = "Folk",
 115     [81] = "Folk-Rock",
 116     [82] = "National Folk",
 117     [83] = "Swing",
 118     [84] = "Fast Fusion",
 119     [85] = "Bebob",
 120     [86] = "Latin",
 121     [87] = "Revival",
 122     [88] = "Celtic",
 123     [89] = "Bluegrass",
 124     [90] = "Avantgarde",
 125     [91] = "Gothic Rock",
 126     [92] = "Progressive Rock",
 127     [93] = "Psychedelic Rock",
 128     [94] = "Symphonic Rock",
 129     [95] = "Slow Rock",
 130     [96] = "Big Band",
 131     [97] = "Chorus",
 132     [98] = "Easy Listening",
 133     [99] = "Acoustic",
 134     [100] = "Humour",
 135     [101] = "Speech",
 136     [102] = "Chanson",
 137     [103] = "Opera",
 138     [104] = "Chamber Music",
 139     [105] = "Sonata",
 140     [106] = "Symphony",
 141     [107] = "Booty Bass",
 142     [108] = "Primus",
 143     [109] = "Porn Groove",
 144     [110] = "Satire",
 145     [111] = "Slow Jam",
 146     [112] = "Club",
 147     [113] = "Tango",
 148     [114] = "Samba",
 149     [115] = "Folklore",
 150     [116] = "Ballad",
 151     [117] = "Power Ballad",
 152     [118] = "Rhythmic Soul",
 153     [119] = "Freestyle",
 154     [120] = "Duet",
 155     [121] = "Punk Rock",
 156     [122] = "Drum Solo",
 157     [123] = "A capella",
 158     [124] = "Euro-House",
 159     [125] = "Dance Hall",
 160 };
 161
 162 /* buf must be ID3v2_HEADER_SIZE byte long */
 163 static int id3v2_match(const uint8_t *buf)
 164 {
 165     return  buf[0] == 'I' &&
 166             buf[1] == 'D' &&
 167             buf[2] == '3' &&
 168             buf[3] != 0xff &&
 169             buf[4] != 0xff &&
 170             (buf[6] & 0x80) == 0 &&
 171             (buf[7] & 0x80) == 0 &&
 172             (buf[8] & 0x80) == 0 &&
 173             (buf[9] & 0x80) == 0;
 174 }
 175
 176 static unsigned int id3v2_get_size(ByteIOContext *s, int len)
 177 {
 178     int v=0;
 179     while(len--)
 180         v= (v<<7) + (get_byte(s)&0x7F);
 181     return v;
 182 }
 183
 184 static void id3v2_read_ttag(AVFormatContext *s, int taglen, char *dst, int dstlen)
 185 {
 186     char *q;
 187     int len;
 188
 189     if(dstlen > 0)
 190         dst[0]= 0;
 191     if(taglen < 1)
 192         return;
 193
 194     taglen--; /* account for encoding type byte */
 195     dstlen--; /* Leave space for zero terminator */
 196
 197     switch(get_byte(s->pb)) { /* encoding type */
 198
 199     case 0:  /* ISO-8859-1 (0 - 255 maps directly into unicode) */
 200         q = dst;
 201         while(taglen--) {
 202             uint8_t tmp;
 203             PUT_UTF8(get_byte(s->pb), tmp, if (q - dst < dstlen - 1) *q++ = tmp;)
 204         }
 205         *q = '\0';
 206         break;
 207
 208     case 3:  /* UTF-8 */
 209         len = FFMIN(taglen, dstlen-1);
 210         get_buffer(s->pb, dst, len);
 211         dst[len] = 0;
 212         break;
 213     }
 214 }
 215
 216 /**
 217  * ID3v2 parser
 218  *
 219  * Handles ID3v2.2, 2.3 and 2.4.
 220  *
 221  */
 222
 223 static void id3v2_parse(AVFormatContext *s, int len, uint8_t version, uint8_t flags)
 224 {
 225     int isv34, tlen;
 226     uint32_t tag;
 227     offset_t next;
 228     char tmp[16];
 229     int taghdrlen;
 230     const char *reason;
 231
 232     switch(version) {
 233     case 2:
 234         if(flags & 0x40) {
 235             reason = "compression";
 236             goto error;
 237         }
 238         isv34 = 0;
 239         taghdrlen = 6;
 240         break;
 241
 242     case 3:
 243     case 4:
 244         isv34 = 1;
 245         taghdrlen = 10;
 246         break;
 247
 248     default:
 249         reason = "version";
 250         goto error;
 251     }
 252
 253     if(flags & 0x80) {
 254         reason = "unsynchronization";
 255         goto error;
 256     }
 257
 258     if(isv34 && flags & 0x40) /* Extended header present, just skip over it */
 259         url_fskip(s->pb, id3v2_get_size(s->pb, 4));
 260
 261     while(len >= taghdrlen) {
 262         if(isv34) {
 263             tag  = get_be32(s->pb);
 264             tlen = id3v2_get_size(s->pb, 4);
 265             get_be16(s->pb); /* flags */
 266         } else {
 267             tag  = get_be24(s->pb);
 268             tlen = id3v2_get_size(s->pb, 3);
 269         }
 270         len -= taghdrlen + tlen;
 271
 272         if(len < 0)
 273             break;
 274
 275         next = url_ftell(s->pb) + tlen;
 276
 277         switch(tag) {
 278         case MKBETAG('T', 'I', 'T', '2'):
 279         case MKBETAG(0,   'T', 'T', '2'):
 280             id3v2_read_ttag(s, tlen, s->title, sizeof(s->title));
 281             break;
 282         case MKBETAG('T', 'P', 'E', '1'):
 283         case MKBETAG(0,   'T', 'P', '1'):
 284             id3v2_read_ttag(s, tlen, s->author, sizeof(s->author));
 285             break;
 286         case MKBETAG('T', 'A', 'L', 'B'):
 287         case MKBETAG(0,   'T', 'A', 'L'):
 288             id3v2_read_ttag(s, tlen, s->album, sizeof(s->album));
 289             break;
 290         case MKBETAG('T', 'C', 'O', 'N'):
 291         case MKBETAG(0,   'T', 'C', 'O'):
 292             id3v2_read_ttag(s, tlen, s->genre, sizeof(s->genre));
 293             break;
 294         case MKBETAG('T', 'C', 'O', 'P'):
 295         case MKBETAG(0,   'T', 'C', 'R'):
 296             id3v2_read_ttag(s, tlen, s->copyright, sizeof(s->copyright));
 297             break;
 298         case MKBETAG('T', 'R', 'C', 'K'):
 299         case MKBETAG(0,   'T', 'R', 'K'):
 300             id3v2_read_ttag(s, tlen, tmp, sizeof(tmp));
 301             s->track = atoi(tmp);
 302             break;
 303         case 0:
 304             /* padding, skip to end */
 305             url_fskip(s->pb, len);
 306             len = 0;
 307             continue;
 308         }
 309         /* Skip to end of tag */
 310         url_fseek(s->pb, next, SEEK_SET);
 311     }
 312
 313     if(version == 4 && flags & 0x10) /* Footer preset, always 10 bytes, skip over it */
 314         url_fskip(s->pb, 10);
 315     return;
 316
 317   error:
 318     av_log(s, AV_LOG_INFO, "ID3v2.%d tag skipped, cannot handle %s\n", version, reason);
 319     url_fskip(s->pb, len);
 320 }
 321
 322 static void id3v1_get_string(char *str, int str_size,
 323                              const uint8_t *buf, int buf_size)
 324 {
 325     int i, c;
 326     char *q;
 327
 328     q = str;
 329     for(i = 0; i < buf_size; i++) {
 330         c = buf[i];
 331         if (c == '\0')
 332             break;
 333         if ((q - str) >= str_size - 1)
 334             break;
 335         *q++ = c;
 336     }
 337     *q = '\0';
 338 }
 339
 340 /* 'buf' must be ID3v1_TAG_SIZE byte long */
 341 static int id3v1_parse_tag(AVFormatContext *s, const uint8_t *buf)
 342 {
 343     char str[5];
 344     int genre;
 345
 346     if (!(buf[0] == 'T' &&
 347           buf[1] == 'A' &&
 348           buf[2] == 'G'))
 349         return -1;
 350     id3v1_get_string(s->title, sizeof(s->title), buf + 3, 30);
 351     id3v1_get_string(s->author, sizeof(s->author), buf + 33, 30);
 352     id3v1_get_string(s->album, sizeof(s->album), buf + 63, 30);
 353     id3v1_get_string(str, sizeof(str), buf + 93, 4);
 354     s->year = atoi(str);
 355     id3v1_get_string(s->comment, sizeof(s->comment), buf + 97, 30);
 356     if (buf[125] == 0 && buf[126] != 0)
 357         s->track = buf[126];
 358     genre = buf[127];
 359     if (genre <= ID3v1_GENRE_MAX)
 360         av_strlcpy(s->genre, id3v1_genre_str[genre], sizeof(s->genre));
 361     return 0;
 362 }
 363
 364 /* mp3 read */
 365
 366 static int mp3_read_probe(AVProbeData *p)
 367 {
 368     int max_frames, first_frames = 0;
 369     int fsize, frames, sample_rate;
 370     uint32_t header;
 371     uint8_t *buf, *buf2, *end;
 372     AVCodecContext avctx;
 373
 374     if(id3v2_match(p->buf))
 375         return AVPROBE_SCORE_MAX/2+1; // this must be less than mpeg-ps because some retards put id3v2 tags before mpeg-ps files
 376
 377     max_frames = 0;
 378     buf = p->buf;
 379     end = buf + p->buf_size - sizeof(uint32_t);
 380
 381     for(; buf < end; buf= buf2+1) {
 382         buf2 = buf;
 383
 384         for(frames = 0; buf2 < end; frames++) {
 385             header = AV_RB32(buf2);
 386             fsize = ff_mpa_decode_header(&avctx, header, &sample_rate);
 387             if(fsize < 0)
 388                 break;
 389             buf2 += fsize;
 390         }
 391         max_frames = FFMAX(max_frames, frames);
 392         if(buf == p->buf)
 393             first_frames= frames;
 394     }
 395     if   (first_frames>=3) return AVPROBE_SCORE_MAX/2+1;
 396     else if(max_frames>500)return AVPROBE_SCORE_MAX/2;
 397     else if(max_frames>=3) return AVPROBE_SCORE_MAX/4;
 398     else if(max_frames>=1) return 1;
 399     else                   return 0;
 400 }
 401
 402 /**
 403  * Try to find Xing/Info/VBRI tags and compute duration from info therein
 404  */
 405 static void mp3_parse_vbr_tags(AVFormatContext *s, AVStream *st, offset_t base)
 406 {
 407     uint32_t v, spf;
 408     int frames = -1; /* Total number of frames in file */
 409     const offset_t xing_offtbl[2][2] = {{32, 17}, {17,9}};
 410     MPADecodeContext c;
 411
 412     v = get_be32(s->pb);
 413     if(ff_mpa_check_header(v) < 0)
 414       return;
 415
 416     ff_mpegaudio_decode_header(&c, v);
 417     if(c.layer != 3)
 418         return;
 419
 420     /* Check for Xing / Info tag */
 421     url_fseek(s->pb, xing_offtbl[c.lsf == 1][c.nb_channels == 1], SEEK_CUR);
 422     v = get_be32(s->pb);
 423     if(v == MKBETAG('X', 'i', 'n', 'g') || v == MKBETAG('I', 'n', 'f', 'o')) {
 424         v = get_be32(s->pb);
 425         if(v & 0x1)
 426             frames = get_be32(s->pb);
 427     }
 428
 429     /* Check for VBRI tag (always 32 bytes after end of mpegaudio header) */
 430     url_fseek(s->pb, base + 4 + 32, SEEK_SET);
 431     v = get_be32(s->pb);
 432     if(v == MKBETAG('V', 'B', 'R', 'I')) {
 433         /* Check tag version */
 434         if(get_be16(s->pb) == 1) {
 435             /* skip delay, quality and total bytes */
 436             url_fseek(s->pb, 8, SEEK_CUR);
 437             frames = get_be32(s->pb);
 438         }
 439     }
 440
 441     if(frames < 0)
 442         return;
 443
 444     spf = c.lsf ? 576 : 1152; /* Samples per frame, layer 3 */
 445     st->duration = av_rescale_q(frames, (AVRational){spf, c.sample_rate},
 446                                 st->time_base);
 447 }
 448
 449 static int mp3_read_header(AVFormatContext *s,
 450                            AVFormatParameters *ap)
 451 {
 452     AVStream *st;
 453     uint8_t buf[ID3v1_TAG_SIZE];
 454     int len, ret, filesize;
 455     offset_t off;
 456
 457     st = av_new_stream(s, 0);
 458     if (!st)
 459         return AVERROR(ENOMEM);
 460
 461     st->codec->codec_type = CODEC_TYPE_AUDIO;
 462     st->codec->codec_id = CODEC_ID_MP3;
 463     st->need_parsing = AVSTREAM_PARSE_FULL;
 464     st->start_time = 0;
 465
 466     /* try to get the TAG */
 467     if (!url_is_streamed(s->pb)) {
 468         /* XXX: change that */
 469         filesize = url_fsize(s->pb);
 470         if (filesize > 128) {
 471             url_fseek(s->pb, filesize - 128, SEEK_SET);
 472             ret = get_buffer(s->pb, buf, ID3v1_TAG_SIZE);
 473             if (ret == ID3v1_TAG_SIZE) {
 474                 id3v1_parse_tag(s, buf);
 475             }
 476             url_fseek(s->pb, 0, SEEK_SET);
 477         }
 478     }
 479
 480     /* if ID3v2 header found, skip it */
 481     ret = get_buffer(s->pb, buf, ID3v2_HEADER_SIZE);
 482     if (ret != ID3v2_HEADER_SIZE)
 483         return -1;
 484     if (id3v2_match(buf)) {
 485         /* parse ID3v2 header */
 486         len = ((buf[6] & 0x7f) << 21) |
 487             ((buf[7] & 0x7f) << 14) |
 488             ((buf[8] & 0x7f) << 7) |
 489             (buf[9] & 0x7f);
 490         id3v2_parse(s, len, buf[3], buf[5]);
 491     } else {
 492         url_fseek(s->pb, 0, SEEK_SET);
 493     }
 494
 495     off = url_ftell(s->pb);
 496     mp3_parse_vbr_tags(s, st, off);
 497     url_fseek(s->pb, off, SEEK_SET);
 498
 499     /* the parameters will be extracted from the compressed bitstream */
 500     return 0;
 501 }
 502
 503 #define MP3_PACKET_SIZE 1024
 504
 505 static int mp3_read_packet(AVFormatContext *s, AVPacket *pkt)
 506 {
 507     int ret, size;
 508     //    AVStream *st = s->streams[0];
 509
 510     size= MP3_PACKET_SIZE;
 511
 512     ret= av_get_packet(s->pb, pkt, size);
 513
 514     pkt->stream_index = 0;
 515     if (ret <= 0) {
 516         return AVERROR(EIO);
 517     }
 518     /* note: we need to modify the packet size here to handle the last
 519        packet */
 520     pkt->size = ret;
 521     return ret;
 522 }
 523
 524 #ifdef CONFIG_MUXERS
 525 static void id3v1_create_tag(AVFormatContext *s, uint8_t *buf)
 526 {
 527     int v, i;
 528
 529     memset(buf, 0, ID3v1_TAG_SIZE); /* fail safe */
 530     buf[0] = 'T';
 531     buf[1] = 'A';
 532     buf[2] = 'G';
 533     strncpy(buf + 3, s->title, 30);
 534     strncpy(buf + 33, s->author, 30);
 535     strncpy(buf + 63, s->album, 30);
 536     v = s->year;
 537     if (v > 0) {
 538         for(i = 0;i < 4; i++) {
 539             buf[96 - i] = '0' + (v % 10);
 540             v = v / 10;
 541         }
 542     }
 543     strncpy(buf + 97, s->comment, 30);
 544     if (s->track != 0) {
 545         buf[125] = 0;
 546         buf[126] = s->track;
 547     }
 548     for(i = 0; i <= ID3v1_GENRE_MAX; i++) {
 549         if (!strcasecmp(s->genre, id3v1_genre_str[i])) {
 550             buf[127] = i;
 551             break;
 552         }
 553     }
 554 }
 555
 556 /* simple formats */
 557
 558 static void id3v2_put_size(AVFormatContext *s, int size)
 559 {
 560     put_byte(s->pb, size >> 21 & 0x7f);
 561     put_byte(s->pb, size >> 14 & 0x7f);
 562     put_byte(s->pb, size >> 7  & 0x7f);
 563     put_byte(s->pb, size       & 0x7f);
 564 }
 565
 566 static void id3v2_put_ttag(AVFormatContext *s, const char *string, uint32_t tag)
 567 {
 568     int len = strlen(string);
 569     put_be32(s->pb, tag);
 570     id3v2_put_size(s, len + 1);
 571     put_be16(s->pb, 0);
 572     put_byte(s->pb, 3); /* UTF-8 */
 573     put_buffer(s->pb, string, len);
 574 }
 575
 576
 577 /**
 578  * Write an ID3v2.4 header at beginning of stream
 579  */
 580
 581 static int mp3_write_header(struct AVFormatContext *s)
 582 {
 583     int totlen = 0;
 584     char tracktxt[10];
 585     char yeartxt[10];
 586
 587     if(s->track)
 588         snprintf(tracktxt, sizeof(tracktxt), "%d", s->track);
 589     if(s->year)
 590         snprintf( yeartxt, sizeof(yeartxt) , "%d", s->year );
 591
 592     if(s->title[0])     totlen += 11 + strlen(s->title);
 593     if(s->author[0])    totlen += 11 + strlen(s->author);
 594     if(s->album[0])     totlen += 11 + strlen(s->album);
 595     if(s->genre[0])     totlen += 11 + strlen(s->genre);
 596     if(s->copyright[0]) totlen += 11 + strlen(s->copyright);
 597     if(s->track)        totlen += 11 + strlen(tracktxt);
 598     if(s->year)         totlen += 11 + strlen(yeartxt);
 599     if(!(s->streams[0]->codec->flags & CODEC_FLAG_BITEXACT))
 600         totlen += strlen(LIBAVFORMAT_IDENT) + 11;
 601
 602     if(totlen == 0)
 603         return 0;
 604
 605     put_be32(s->pb, MKBETAG('I', 'D', '3', 0x04)); /* ID3v2.4 */
 606     put_byte(s->pb, 0);
 607     put_byte(s->pb, 0); /* flags */
 608
 609     id3v2_put_size(s, totlen);
 610
 611     if(s->title[0])     id3v2_put_ttag(s, s->title,     MKBETAG('T', 'I', 'T', '2'));
 612     if(s->author[0])    id3v2_put_ttag(s, s->author,    MKBETAG('T', 'P', 'E', '1'));
 613     if(s->album[0])     id3v2_put_ttag(s, s->album,     MKBETAG('T', 'A', 'L', 'B'));
 614     if(s->genre[0])     id3v2_put_ttag(s, s->genre,     MKBETAG('T', 'C', 'O', 'N'));
 615     if(s->copyright[0]) id3v2_put_ttag(s, s->copyright, MKBETAG('T', 'C', 'O', 'P'));
 616     if(s->track)        id3v2_put_ttag(s, tracktxt,     MKBETAG('T', 'R', 'C', 'K'));
 617     if(s->year)         id3v2_put_ttag(s, yeartxt,      MKBETAG('T', 'Y', 'E', 'R'));
 618     if(!(s->streams[0]->codec->flags & CODEC_FLAG_BITEXACT))
 619         id3v2_put_ttag(s, LIBAVFORMAT_IDENT,            MKBETAG('T', 'E', 'N', 'C'));
 620     return 0;
 621 }
 622
 623 static int mp3_write_packet(struct AVFormatContext *s, AVPacket *pkt)
 624 {
 625     put_buffer(s->pb, pkt->data, pkt->size);
 626     put_flush_packet(s->pb);
 627     return 0;
 628 }
 629
 630 static int mp3_write_trailer(struct AVFormatContext *s)
 631 {
 632     uint8_t buf[ID3v1_TAG_SIZE];
 633
 634     /* write the id3v1 tag */
 635     if (s->title[0] != '\0') {
 636         id3v1_create_tag(s, buf);
 637         put_buffer(s->pb, buf, ID3v1_TAG_SIZE);
 638         put_flush_packet(s->pb);
 639     }
 640     return 0;
 641 }
 642 #endif //CONFIG_MUXERS
 643
 644 #ifdef CONFIG_MP3_DEMUXER
 645 AVInputFormat mp3_demuxer = {
 646     "mp3",
 647     NULL_IF_CONFIG_SMALL("MPEG audio"),
 648     0,
 649     mp3_read_probe,
 650     mp3_read_header,
 651     mp3_read_packet,
 652     .flags= AVFMT_GENERIC_INDEX,
 653     .extensions = "mp2,mp3,m2a", /* XXX: use probe */
 654 };
 655 #endif
 656 #ifdef CONFIG_MP2_MUXER
 657 AVOutputFormat mp2_muxer = {
 658     "mp2",
 659     NULL_IF_CONFIG_SMALL("MPEG audio layer 2"),
 660     "audio/x-mpeg",
 661 #ifdef CONFIG_LIBMP3LAME
 662     "mp2,m2a",
 663 #else
 664     "mp2,mp3,m2a",
 665 #endif
 666     0,
 667     CODEC_ID_MP2,
 668     CODEC_ID_NONE,
 669     NULL,
 670     mp3_write_packet,
 671     mp3_write_trailer,
 672 };
 673 #endif
 674 #ifdef CONFIG_MP3_MUXER
 675 AVOutputFormat mp3_muxer = {
 676     "mp3",
 677     NULL_IF_CONFIG_SMALL("MPEG audio layer 3"),
 678     "audio/x-mpeg",
 679     "mp3",
 680     0,
 681     CODEC_ID_MP3,
 682     CODEC_ID_NONE,
 683     mp3_write_header,
 684     mp3_write_packet,
 685     mp3_write_trailer,
 686 };
 687 #endif