libavformat/id3v2.c

   1 /*
   2  * ID3v2 header parser
   3  * Copyright (c) 2003 Fabrice Bellard
   4  *
   5  * This file is part of Libav.
   6  *
   7  * Libav 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  * Libav 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 Libav; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  20  */
  21
  22 #include "id3v2.h"
  23 #include "id3v1.h"
  24 #include "libavutil/avstring.h"
  25 #include "libavutil/intreadwrite.h"
  26 #include "libavutil/dict.h"
  27 #include "avio_internal.h"
  28 #include "internal.h"
  29
  30 const AVMetadataConv ff_id3v2_34_metadata_conv[] = {
  31     { "TALB", "album"},
  32     { "TCOM", "composer"},
  33     { "TCON", "genre"},
  34     { "TCOP", "copyright"},
  35     { "TENC", "encoded_by"},
  36     { "TIT2", "title"},
  37     { "TLAN", "language"},
  38     { "TPE1", "artist"},
  39     { "TPE2", "album_artist"},
  40     { "TPE3", "performer"},
  41     { "TPOS", "disc"},
  42     { "TPUB", "publisher"},
  43     { "TRCK", "track"},
  44     { "TSSE", "encoder"},
  45     { 0 }
  46 };
  47
  48 const AVMetadataConv ff_id3v2_4_metadata_conv[] = {
  49     { "TDRL", "date"},
  50     { "TDRC", "date"},
  51     { "TDEN", "creation_time"},
  52     { "TSOA", "album-sort"},
  53     { "TSOP", "artist-sort"},
  54     { "TSOT", "title-sort"},
  55     { 0 }
  56 };
  57
  58 static const AVMetadataConv id3v2_2_metadata_conv[] = {
  59     { "TAL",  "album"},
  60     { "TCO",  "genre"},
  61     { "TT2",  "title"},
  62     { "TEN",  "encoded_by"},
  63     { "TP1",  "artist"},
  64     { "TP2",  "album_artist"},
  65     { "TP3",  "performer"},
  66     { "TRK",  "track"},
  67     { 0 }
  68 };
  69
  70
  71 const char ff_id3v2_tags[][4] = {
  72    "TALB", "TBPM", "TCOM", "TCON", "TCOP", "TDLY", "TENC", "TEXT",
  73    "TFLT", "TIT1", "TIT2", "TIT3", "TKEY", "TLAN", "TLEN", "TMED",
  74    "TOAL", "TOFN", "TOLY", "TOPE", "TOWN", "TPE1", "TPE2", "TPE3",
  75    "TPE4", "TPOS", "TPUB", "TRCK", "TRSN", "TRSO", "TSRC", "TSSE",
  76    { 0 },
  77 };
  78
  79 const char ff_id3v2_4_tags[][4] = {
  80    "TDEN", "TDOR", "TDRC", "TDRL", "TDTG", "TIPL", "TMCL", "TMOO",
  81    "TPRO", "TSOA", "TSOP", "TSOT", "TSST",
  82    { 0 },
  83 };
  84
  85 const char ff_id3v2_3_tags[][4] = {
  86    "TDAT", "TIME", "TORY", "TRDA", "TSIZ", "TYER",
  87    { 0 },
  88 };
  89
  90 const char *ff_id3v2_picture_types[21] = {
  91     "Other",
  92     "32x32 pixels 'file icon'",
  93     "Other file icon",
  94     "Cover (front)",
  95     "Cover (back)",
  96     "Leaflet page",
  97     "Media (e.g. label side of CD)",
  98     "Lead artist/lead performer/soloist",
  99     "Artist/performer",
 100     "Conductor",
 101     "Band/Orchestra",
 102     "Composer",
 103     "Lyricist/text writer",
 104     "Recording Location",
 105     "During recording",
 106     "During performance",
 107     "Movie/video screen capture",
 108     "A bright coloured fish",
 109     "Illustration",
 110     "Band/artist logotype",
 111     "Publisher/Studio logotype",
 112 };
 113
 114 const CodecMime ff_id3v2_mime_tags[] = {
 115     {"image/gif" , AV_CODEC_ID_GIF},
 116     {"image/jpeg", AV_CODEC_ID_MJPEG},
 117     {"image/jpg",  AV_CODEC_ID_MJPEG},
 118     {"image/png" , AV_CODEC_ID_PNG},
 119     {"image/tiff", AV_CODEC_ID_TIFF},
 120     {"image/bmp",  AV_CODEC_ID_BMP},
 121     {"JPG",        AV_CODEC_ID_MJPEG}, /* ID3v2.2  */
 122     {"PNG" ,       AV_CODEC_ID_PNG},   /* ID3v2.2  */
 123     {"",           AV_CODEC_ID_NONE},
 124 };
 125
 126 int ff_id3v2_match(const uint8_t *buf, const char * magic)
 127 {
 128     return  buf[0]         == magic[0] &&
 129             buf[1]         == magic[1] &&
 130             buf[2]         == magic[2] &&
 131             buf[3]         != 0xff &&
 132             buf[4]         != 0xff &&
 133            (buf[6] & 0x80) ==    0 &&
 134            (buf[7] & 0x80) ==    0 &&
 135            (buf[8] & 0x80) ==    0 &&
 136            (buf[9] & 0x80) ==    0;
 137 }
 138
 139 int ff_id3v2_tag_len(const uint8_t * buf)
 140 {
 141     int len = ((buf[6] & 0x7f) << 21) +
 142               ((buf[7] & 0x7f) << 14) +
 143               ((buf[8] & 0x7f) << 7) +
 144                (buf[9] & 0x7f) +
 145               ID3v2_HEADER_SIZE;
 146     if (buf[5] & 0x10)
 147         len += ID3v2_HEADER_SIZE;
 148     return len;
 149 }
 150
 151 static unsigned int get_size(AVIOContext *s, int len)
 152 {
 153     int v = 0;
 154     while (len--)
 155         v = (v << 7) + (avio_r8(s) & 0x7F);
 156     return v;
 157 }
 158
 159 /**
 160  * Free GEOB type extra metadata.
 161  */
 162 static void free_geobtag(void *obj)
 163 {
 164     ID3v2ExtraMetaGEOB *geob = obj;
 165     av_free(geob->mime_type);
 166     av_free(geob->file_name);
 167     av_free(geob->description);
 168     av_free(geob->data);
 169     av_free(geob);
 170 }
 171
 172 /**
 173  * Decode characters to UTF-8 according to encoding type. The decoded buffer is
 174  * always null terminated. Stop reading when either *maxread bytes are read from
 175  * pb or U+0000 character is found.
 176  *
 177  * @param dst Pointer where the address of the buffer with the decoded bytes is
 178  * stored. Buffer must be freed by caller.
 179  * @param maxread Pointer to maximum number of characters to read from the
 180  * AVIOContext. After execution the value is decremented by the number of bytes
 181  * actually read.
 182  * @returns 0 if no error occurred, dst is uninitialized on error
 183  */
 184 static int decode_str(AVFormatContext *s, AVIOContext *pb, int encoding,
 185                       uint8_t **dst, int *maxread)
 186 {
 187     int ret;
 188     uint8_t tmp;
 189     uint32_t ch = 1;
 190     int left = *maxread;
 191     unsigned int (*get)(AVIOContext*) = avio_rb16;
 192     AVIOContext *dynbuf;
 193
 194     if ((ret = avio_open_dyn_buf(&dynbuf)) < 0) {
 195         av_log(s, AV_LOG_ERROR, "Error opening memory stream\n");
 196         return ret;
 197     }
 198
 199     switch (encoding) {
 200
 201     case ID3v2_ENCODING_ISO8859:
 202         while (left && ch) {
 203             ch = avio_r8(pb);
 204             PUT_UTF8(ch, tmp, avio_w8(dynbuf, tmp);)
 205             left--;
 206         }
 207         break;
 208
 209     case ID3v2_ENCODING_UTF16BOM:
 210         if ((left -= 2) < 0) {
 211             av_log(s, AV_LOG_ERROR, "Cannot read BOM value, input too short\n");
 212             avio_close_dyn_buf(dynbuf, dst);
 213             av_freep(dst);
 214             return AVERROR_INVALIDDATA;
 215         }
 216         switch (avio_rb16(pb)) {
 217         case 0xfffe:
 218             get = avio_rl16;
 219         case 0xfeff:
 220             break;
 221         default:
 222             av_log(s, AV_LOG_ERROR, "Incorrect BOM value\n");
 223             avio_close_dyn_buf(dynbuf, dst);
 224             av_freep(dst);
 225             *maxread = left;
 226             return AVERROR_INVALIDDATA;
 227         }
 228         // fall-through
 229
 230     case ID3v2_ENCODING_UTF16BE:
 231         while ((left > 1) && ch) {
 232             GET_UTF16(ch, ((left -= 2) >= 0 ? get(pb) : 0), break;)
 233             PUT_UTF8(ch, tmp, avio_w8(dynbuf, tmp);)
 234         }
 235         if (left < 0)
 236             left += 2; /* did not read last char from pb */
 237         break;
 238
 239     case ID3v2_ENCODING_UTF8:
 240         while (left && ch) {
 241             ch = avio_r8(pb);
 242             avio_w8(dynbuf, ch);
 243             left--;
 244         }
 245         break;
 246     default:
 247         av_log(s, AV_LOG_WARNING, "Unknown encoding\n");
 248     }
 249
 250     if (ch)
 251         avio_w8(dynbuf, 0);
 252
 253     avio_close_dyn_buf(dynbuf, dst);
 254     *maxread = left;
 255
 256     return 0;
 257 }
 258
 259 /**
 260  * Parse a text tag.
 261  */
 262 static void read_ttag(AVFormatContext *s, AVIOContext *pb, int taglen, const char *key)
 263 {
 264     uint8_t *dst;
 265     int encoding, dict_flags = AV_DICT_DONT_OVERWRITE | AV_DICT_DONT_STRDUP_VAL;
 266     unsigned genre;
 267
 268     if (taglen < 1)
 269         return;
 270
 271     encoding = avio_r8(pb);
 272     taglen--; /* account for encoding type byte */
 273
 274     if (decode_str(s, pb, encoding, &dst, &taglen) < 0) {
 275         av_log(s, AV_LOG_ERROR, "Error reading frame %s, skipped\n", key);
 276         return;
 277     }
 278
 279     if (!(strcmp(key, "TCON") && strcmp(key, "TCO"))
 280         && (sscanf(dst, "(%d)", &genre) == 1 || sscanf(dst, "%d", &genre) == 1)
 281         && genre <= ID3v1_GENRE_MAX) {
 282         av_freep(&dst);
 283         dst = av_strdup(ff_id3v1_genre_str[genre]);
 284     } else if (!(strcmp(key, "TXXX") && strcmp(key, "TXX"))) {
 285         /* dst now contains the key, need to get value */
 286         key = dst;
 287         if (decode_str(s, pb, encoding, &dst, &taglen) < 0) {
 288             av_log(s, AV_LOG_ERROR, "Error reading frame %s, skipped\n", key);
 289             av_freep(&key);
 290             return;
 291         }
 292         dict_flags |= AV_DICT_DONT_STRDUP_KEY;
 293     } else if (!*dst)
 294         av_freep(&dst);
 295
 296     if (dst)
 297         av_dict_set(&s->metadata, key, dst, dict_flags);
 298 }
 299
 300 /**
 301  * Parse GEOB tag into a ID3v2ExtraMetaGEOB struct.
 302  */
 303 static void read_geobtag(AVFormatContext *s, AVIOContext *pb, int taglen, char *tag, ID3v2ExtraMeta **extra_meta)
 304 {
 305     ID3v2ExtraMetaGEOB *geob_data = NULL;
 306     ID3v2ExtraMeta *new_extra = NULL;
 307     char encoding;
 308     unsigned int len;
 309
 310     if (taglen < 1)
 311         return;
 312
 313     geob_data = av_mallocz(sizeof(ID3v2ExtraMetaGEOB));
 314     if (!geob_data) {
 315         av_log(s, AV_LOG_ERROR, "Failed to alloc %zu bytes\n", sizeof(ID3v2ExtraMetaGEOB));
 316         return;
 317     }
 318
 319     new_extra = av_mallocz(sizeof(ID3v2ExtraMeta));
 320     if (!new_extra) {
 321         av_log(s, AV_LOG_ERROR, "Failed to alloc %zu bytes\n", sizeof(ID3v2ExtraMeta));
 322         goto fail;
 323     }
 324
 325     /* read encoding type byte */
 326     encoding = avio_r8(pb);
 327     taglen--;
 328
 329     /* read MIME type (always ISO-8859) */
 330     if (decode_str(s, pb, ID3v2_ENCODING_ISO8859, &geob_data->mime_type, &taglen) < 0
 331         || taglen <= 0)
 332         goto fail;
 333
 334     /* read file name */
 335     if (decode_str(s, pb, encoding, &geob_data->file_name, &taglen) < 0
 336         || taglen <= 0)
 337         goto fail;
 338
 339     /* read content description */
 340     if (decode_str(s, pb, encoding, &geob_data->description, &taglen) < 0
 341         || taglen < 0)
 342         goto fail;
 343
 344     if (taglen) {
 345         /* save encapsulated binary data */
 346         geob_data->data = av_malloc(taglen);
 347         if (!geob_data->data) {
 348             av_log(s, AV_LOG_ERROR, "Failed to alloc %d bytes\n", taglen);
 349             goto fail;
 350         }
 351         if ((len = avio_read(pb, geob_data->data, taglen)) < taglen)
 352             av_log(s, AV_LOG_WARNING, "Error reading GEOB frame, data truncated.\n");
 353         geob_data->datasize = len;
 354     } else {
 355         geob_data->data = NULL;
 356         geob_data->datasize = 0;
 357     }
 358
 359     /* add data to the list */
 360     new_extra->tag = "GEOB";
 361     new_extra->data = geob_data;
 362     new_extra->next = *extra_meta;
 363     *extra_meta = new_extra;
 364
 365     return;
 366
 367 fail:
 368     av_log(s, AV_LOG_ERROR, "Error reading frame %s, skipped\n", tag);
 369     free_geobtag(geob_data);
 370     av_free(new_extra);
 371     return;
 372 }
 373
 374 static int is_number(const char *str)
 375 {
 376     while (*str >= '0' && *str <= '9') str++;
 377     return !*str;
 378 }
 379
 380 static AVDictionaryEntry* get_date_tag(AVDictionary *m, const char *tag)
 381 {
 382     AVDictionaryEntry *t;
 383     if ((t = av_dict_get(m, tag, NULL, AV_DICT_MATCH_CASE)) &&
 384         strlen(t->value) == 4 && is_number(t->value))
 385         return t;
 386     return NULL;
 387 }
 388
 389 static void merge_date(AVDictionary **m)
 390 {
 391     AVDictionaryEntry *t;
 392     char date[17] = {0};      // YYYY-MM-DD hh:mm
 393
 394     if (!(t = get_date_tag(*m, "TYER")) &&
 395         !(t = get_date_tag(*m, "TYE")))
 396         return;
 397     av_strlcpy(date, t->value, 5);
 398     av_dict_set(m, "TYER", NULL, 0);
 399     av_dict_set(m, "TYE",  NULL, 0);
 400
 401     if (!(t = get_date_tag(*m, "TDAT")) &&
 402         !(t = get_date_tag(*m, "TDA")))
 403         goto finish;
 404     snprintf(date + 4, sizeof(date) - 4, "-%.2s-%.2s", t->value + 2, t->value);
 405     av_dict_set(m, "TDAT", NULL, 0);
 406     av_dict_set(m, "TDA",  NULL, 0);
 407
 408     if (!(t = get_date_tag(*m, "TIME")) &&
 409         !(t = get_date_tag(*m, "TIM")))
 410         goto finish;
 411     snprintf(date + 10, sizeof(date) - 10, " %.2s:%.2s", t->value, t->value + 2);
 412     av_dict_set(m, "TIME", NULL, 0);
 413     av_dict_set(m, "TIM",  NULL, 0);
 414
 415 finish:
 416     if (date[0])
 417         av_dict_set(m, "date", date, 0);
 418 }
 419
 420 static void free_apic(void *obj)
 421 {
 422     ID3v2ExtraMetaAPIC *apic = obj;
 423     av_buffer_unref(&apic->buf);
 424     av_freep(&apic->description);
 425     av_freep(&apic);
 426 }
 427
 428 static void read_apic(AVFormatContext *s, AVIOContext *pb, int taglen, char *tag, ID3v2ExtraMeta **extra_meta)
 429 {
 430     int enc, pic_type;
 431     char             mimetype[64];
 432     const CodecMime     *mime = ff_id3v2_mime_tags;
 433     enum AVCodecID           id = AV_CODEC_ID_NONE;
 434     ID3v2ExtraMetaAPIC  *apic = NULL;
 435     ID3v2ExtraMeta *new_extra = NULL;
 436     int64_t               end = avio_tell(pb) + taglen;
 437
 438     if (taglen <= 4)
 439         goto fail;
 440
 441     new_extra = av_mallocz(sizeof(*new_extra));
 442     apic      = av_mallocz(sizeof(*apic));
 443     if (!new_extra || !apic)
 444         goto fail;
 445
 446     enc = avio_r8(pb);
 447     taglen--;
 448
 449     /* mimetype */
 450     taglen -= avio_get_str(pb, taglen, mimetype, sizeof(mimetype));
 451     while (mime->id != AV_CODEC_ID_NONE) {
 452         if (!av_strncasecmp(mime->str, mimetype, sizeof(mimetype))) {
 453             id = mime->id;
 454             break;
 455         }
 456         mime++;
 457     }
 458     if (id == AV_CODEC_ID_NONE) {
 459         av_log(s, AV_LOG_WARNING, "Unknown attached picture mimetype: %s, skipping.\n", mimetype);
 460         goto fail;
 461     }
 462     apic->id = id;
 463
 464     /* picture type */
 465     pic_type = avio_r8(pb);
 466     taglen--;
 467     if (pic_type < 0 || pic_type >= FF_ARRAY_ELEMS(ff_id3v2_picture_types)) {
 468         av_log(s, AV_LOG_WARNING, "Unknown attached picture type %d.\n", pic_type);
 469         pic_type = 0;
 470     }
 471     apic->type = ff_id3v2_picture_types[pic_type];
 472
 473     /* description and picture data */
 474     if (decode_str(s, pb, enc, &apic->description, &taglen) < 0) {
 475         av_log(s, AV_LOG_ERROR, "Error decoding attached picture description.\n");
 476         goto fail;
 477     }
 478
 479     apic->buf = av_buffer_alloc(taglen);
 480     if (!apic->buf || avio_read(pb, apic->buf->data, taglen) != taglen)
 481         goto fail;
 482
 483     new_extra->tag    = "APIC";
 484     new_extra->data   = apic;
 485     new_extra->next   = *extra_meta;
 486     *extra_meta       = new_extra;
 487
 488     return;
 489
 490 fail:
 491     if (apic)
 492         free_apic(apic);
 493     av_freep(&new_extra);
 494     avio_seek(pb, end, SEEK_SET);
 495 }
 496
 497 typedef struct ID3v2EMFunc {
 498     const char *tag3;
 499     const char *tag4;
 500     void (*read)(AVFormatContext*, AVIOContext*, int, char*, ID3v2ExtraMeta **);
 501     void (*free)(void *obj);
 502 } ID3v2EMFunc;
 503
 504 static const ID3v2EMFunc id3v2_extra_meta_funcs[] = {
 505     { "GEO", "GEOB", read_geobtag, free_geobtag },
 506     { "PIC", "APIC", read_apic,    free_apic },
 507     { NULL }
 508 };
 509
 510 /**
 511  * Get the corresponding ID3v2EMFunc struct for a tag.
 512  * @param isv34 Determines if v2.2 or v2.3/4 strings are used
 513  * @return A pointer to the ID3v2EMFunc struct if found, NULL otherwise.
 514  */
 515 static const ID3v2EMFunc *get_extra_meta_func(const char *tag, int isv34)
 516 {
 517     int i = 0;
 518     while (id3v2_extra_meta_funcs[i].tag3) {
 519         if (!memcmp(tag,
 520                     (isv34 ? id3v2_extra_meta_funcs[i].tag4 :
 521                              id3v2_extra_meta_funcs[i].tag3),
 522                     (isv34 ? 4 : 3)))
 523             return &id3v2_extra_meta_funcs[i];
 524         i++;
 525     }
 526     return NULL;
 527 }
 528
 529 static void ff_id3v2_parse(AVFormatContext *s, int len, uint8_t version, uint8_t flags, ID3v2ExtraMeta **extra_meta)
 530 {
 531     int isv34, tlen, unsync;
 532     char tag[5];
 533     int64_t next, end = avio_tell(s->pb) + len;
 534     int taghdrlen;
 535     const char *reason = NULL;
 536     AVIOContext pb;
 537     AVIOContext *pbx;
 538     unsigned char *buffer = NULL;
 539     int buffer_size = 0;
 540     const ID3v2EMFunc *extra_func;
 541
 542     switch (version) {
 543     case 2:
 544         if (flags & 0x40) {
 545             reason = "compression";
 546             goto error;
 547         }
 548         isv34 = 0;
 549         taghdrlen = 6;
 550         break;
 551
 552     case 3:
 553     case 4:
 554         isv34 = 1;
 555         taghdrlen = 10;
 556         break;
 557
 558     default:
 559         reason = "version";
 560         goto error;
 561     }
 562
 563     unsync = flags & 0x80;
 564
 565     if (isv34 && flags & 0x40) { /* Extended header present, just skip over it */
 566         int extlen = get_size(s->pb, 4);
 567         if (version == 4)
 568             extlen -= 4;     // in v2.4 the length includes the length field we just read
 569
 570         if (extlen < 0) {
 571             reason = "invalid extended header length";
 572             goto error;
 573         }
 574         avio_skip(s->pb, extlen);
 575     }
 576
 577     while (len >= taghdrlen) {
 578         unsigned int tflags = 0;
 579         int tunsync = 0;
 580
 581         if (isv34) {
 582             avio_read(s->pb, tag, 4);
 583             tag[4] = 0;
 584             if(version==3){
 585                 tlen = avio_rb32(s->pb);
 586             }else
 587                 tlen = get_size(s->pb, 4);
 588             tflags = avio_rb16(s->pb);
 589             tunsync = tflags & ID3v2_FLAG_UNSYNCH;
 590         } else {
 591             avio_read(s->pb, tag, 3);
 592             tag[3] = 0;
 593             tlen = avio_rb24(s->pb);
 594         }
 595         if (tlen < 0 || tlen > len - taghdrlen) {
 596             av_log(s, AV_LOG_WARNING, "Invalid size in frame %s, skipping the rest of tag.\n", tag);
 597             break;
 598         }
 599         len -= taghdrlen + tlen;
 600         next = avio_tell(s->pb) + tlen;
 601
 602         if (!tlen) {
 603             if (tag[0])
 604                 av_log(s, AV_LOG_DEBUG, "Invalid empty frame %s, skipping.\n", tag);
 605             continue;
 606         }
 607
 608         if (tflags & ID3v2_FLAG_DATALEN) {
 609             avio_rb32(s->pb);
 610             tlen -= 4;
 611         }
 612
 613         if (tflags & (ID3v2_FLAG_ENCRYPTION | ID3v2_FLAG_COMPRESSION)) {
 614             av_log(s, AV_LOG_WARNING, "Skipping encrypted/compressed ID3v2 frame %s.\n", tag);
 615             avio_skip(s->pb, tlen);
 616         /* check for text tag or supported special meta tag */
 617         } else if (tag[0] == 'T' || (extra_meta && (extra_func = get_extra_meta_func(tag, isv34)))) {
 618             if (unsync || tunsync) {
 619                 int64_t end = avio_tell(s->pb) + tlen;
 620                 uint8_t *b;
 621                 av_fast_malloc(&buffer, &buffer_size, tlen);
 622                 if (!buffer) {
 623                     av_log(s, AV_LOG_ERROR, "Failed to alloc %d bytes\n", tlen);
 624                     goto seek;
 625                 }
 626                 b = buffer;
 627                 while (avio_tell(s->pb) < end) {
 628                     *b++ = avio_r8(s->pb);
 629                     if (*(b - 1) == 0xff && avio_tell(s->pb) < end - 1) {
 630                         uint8_t val = avio_r8(s->pb);
 631                         *b++ = val ? val : avio_r8(s->pb);
 632                     }
 633                 }
 634                 ffio_init_context(&pb, buffer, b - buffer, 0, NULL, NULL, NULL, NULL);
 635                 tlen = b - buffer;
 636                 pbx = &pb; // read from sync buffer
 637             } else {
 638                 pbx = s->pb; // read straight from input
 639             }
 640             if (tag[0] == 'T')
 641                 /* parse text tag */
 642                 read_ttag(s, pbx, tlen, tag);
 643             else
 644                 /* parse special meta tag */
 645                 extra_func->read(s, pbx, tlen, tag, extra_meta);
 646         }
 647         else if (!tag[0]) {
 648             if (tag[1])
 649                 av_log(s, AV_LOG_WARNING, "invalid frame id, assuming padding");
 650             avio_skip(s->pb, tlen);
 651             break;
 652         }
 653         /* Skip to end of tag */
 654 seek:
 655         avio_seek(s->pb, next, SEEK_SET);
 656     }
 657
 658     if (version == 4 && flags & 0x10) /* Footer preset, always 10 bytes, skip over it */
 659         end += 10;
 660
 661   error:
 662     if (reason)
 663         av_log(s, AV_LOG_INFO, "ID3v2.%d tag skipped, cannot handle %s\n", version, reason);
 664     avio_seek(s->pb, end, SEEK_SET);
 665     av_free(buffer);
 666     return;
 667 }
 668
 669 void ff_id3v2_read(AVFormatContext *s, const char *magic, ID3v2ExtraMeta **extra_meta)
 670 {
 671     int len, ret;
 672     uint8_t buf[ID3v2_HEADER_SIZE];
 673     int     found_header;
 674     int64_t off;
 675
 676     do {
 677         /* save the current offset in case there's nothing to read/skip */
 678         off = avio_tell(s->pb);
 679         ret = avio_read(s->pb, buf, ID3v2_HEADER_SIZE);
 680         if (ret != ID3v2_HEADER_SIZE)
 681             break;
 682             found_header = ff_id3v2_match(buf, magic);
 683             if (found_header) {
 684             /* parse ID3v2 header */
 685             len = ((buf[6] & 0x7f) << 21) |
 686                   ((buf[7] & 0x7f) << 14) |
 687                   ((buf[8] & 0x7f) << 7) |
 688                    (buf[9] & 0x7f);
 689             ff_id3v2_parse(s, len, buf[3], buf[5], extra_meta);
 690         } else {
 691             avio_seek(s->pb, off, SEEK_SET);
 692         }
 693     } while (found_header);
 694     ff_metadata_conv(&s->metadata, NULL, ff_id3v2_34_metadata_conv);
 695     ff_metadata_conv(&s->metadata, NULL, id3v2_2_metadata_conv);
 696     ff_metadata_conv(&s->metadata, NULL, ff_id3v2_4_metadata_conv);
 697     merge_date(&s->metadata);
 698 }
 699
 700 void ff_id3v2_free_extra_meta(ID3v2ExtraMeta **extra_meta)
 701 {
 702     ID3v2ExtraMeta *current = *extra_meta, *next;
 703     const ID3v2EMFunc *extra_func;
 704
 705     while (current) {
 706         if ((extra_func = get_extra_meta_func(current->tag, 1)))
 707             extra_func->free(current->data);
 708         next = current->next;
 709         av_freep(&current);
 710         current = next;
 711     }
 712 }
 713
 714 int ff_id3v2_parse_apic(AVFormatContext *s, ID3v2ExtraMeta **extra_meta)
 715 {
 716     ID3v2ExtraMeta *cur;
 717
 718     for (cur = *extra_meta; cur; cur = cur->next) {
 719         ID3v2ExtraMetaAPIC *apic;
 720         AVStream *st;
 721
 722         if (strcmp(cur->tag, "APIC"))
 723             continue;
 724         apic = cur->data;
 725
 726         if (!(st = avformat_new_stream(s, NULL)))
 727             return AVERROR(ENOMEM);
 728
 729         st->disposition      |= AV_DISPOSITION_ATTACHED_PIC;
 730         st->codec->codec_type = AVMEDIA_TYPE_VIDEO;
 731         st->codec->codec_id   = apic->id;
 732         av_dict_set(&st->metadata, "title",   apic->description, 0);
 733         av_dict_set(&st->metadata, "comment", apic->type, 0);
 734
 735         av_init_packet(&st->attached_pic);
 736         st->attached_pic.buf          = apic->buf;
 737         st->attached_pic.data         = apic->buf->data;
 738         st->attached_pic.size         = apic->buf->size;
 739         st->attached_pic.stream_index = st->index;
 740         st->attached_pic.flags       |= AV_PKT_FLAG_KEY;
 741
 742         apic->buf = NULL;
 743     }
 744
 745     return 0;
 746 }