aboutsummaryrefslogtreecommitdiffstats
path: root/libavformat/id3v2.c
blob: b8994b2226334c6222eb3dc6d86eed2e811625c4 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
/*
 * ID3v2 header parser
 * Copyright (c) 2003 Fabrice Bellard
 *
 * This file is part of Libav.
 *
 * Libav is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * Libav is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with Libav; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

#include "libavutil/avstring.h"
#include "libavutil/dict.h"
#include "libavutil/intreadwrite.h"
#include "avio_internal.h"
#include "internal.h"
#include "id3v1.h"
#include "id3v2.h"

const AVMetadataConv ff_id3v2_34_metadata_conv[] = {
    { "TALB", "album"        },
    { "TCOM", "composer"     },
    { "TCON", "genre"        },
    { "TCOP", "copyright"    },
    { "TENC", "encoded_by"   },
    { "TIT2", "title"        },
    { "TLAN", "language"     },
    { "TPE1", "artist"       },
    { "TPE2", "album_artist" },
    { "TPE3", "performer"    },
    { "TPOS", "disc"         },
    { "TPUB", "publisher"    },
    { "TRCK", "track"        },
    { "TSSE", "encoder"      },
    { 0 }
};

const AVMetadataConv ff_id3v2_4_metadata_conv[] = {
    { "TDRL", "date"          },
    { "TDRC", "date"          },
    { "TDEN", "creation_time" },
    { "TSOA", "album-sort"    },
    { "TSOP", "artist-sort"   },
    { "TSOT", "title-sort"    },
    { 0 }
};

static const AVMetadataConv id3v2_2_metadata_conv[] = {
    { "TAL", "album"        },
    { "TCO", "genre"        },
    { "TT2", "title"        },
    { "TEN", "encoded_by"   },
    { "TP1", "artist"       },
    { "TP2", "album_artist" },
    { "TP3", "performer"    },
    { "TRK", "track"        },
    { 0 }
};

const char ff_id3v2_tags[][4] = {
    "TALB", "TBPM", "TCOM", "TCON", "TCOP", "TDLY", "TENC", "TEXT",
    "TFLT", "TIT1", "TIT2", "TIT3", "TKEY", "TLAN", "TLEN", "TMED",
    "TOAL", "TOFN", "TOLY", "TOPE", "TOWN", "TPE1", "TPE2", "TPE3",
    "TPE4", "TPOS", "TPUB", "TRCK", "TRSN", "TRSO", "TSRC", "TSSE",
    { 0 },
};

const char ff_id3v2_4_tags[][4] = {
    "TDEN", "TDOR", "TDRC", "TDRL", "TDTG", "TIPL", "TMCL", "TMOO",
    "TPRO", "TSOA", "TSOP", "TSOT", "TSST",
    { 0 },
};

const char ff_id3v2_3_tags[][4] = {
    "TDAT", "TIME", "TORY", "TRDA", "TSIZ", "TYER",
    { 0 },
};

const char *ff_id3v2_picture_types[21] = {
    "Other",
    "32x32 pixels 'file icon'",
    "Other file icon",
    "Cover (front)",
    "Cover (back)",
    "Leaflet page",
    "Media (e.g. label side of CD)",
    "Lead artist/lead performer/soloist",
    "Artist/performer",
    "Conductor",
    "Band/Orchestra",
    "Composer",
    "Lyricist/text writer",
    "Recording Location",
    "During recording",
    "During performance",
    "Movie/video screen capture",
    "A bright coloured fish",
    "Illustration",
    "Band/artist logotype",
    "Publisher/Studio logotype",
};

const CodecMime ff_id3v2_mime_tags[] = {
    { "image/gif",  AV_CODEC_ID_GIF   },
    { "image/jpeg", AV_CODEC_ID_MJPEG },
    { "image/jpg",  AV_CODEC_ID_MJPEG },
    { "image/png",  AV_CODEC_ID_PNG   },
    { "image/tiff", AV_CODEC_ID_TIFF  },
    { "image/bmp",  AV_CODEC_ID_BMP   },
    { "JPG",        AV_CODEC_ID_MJPEG }, /* ID3v2.2  */
    { "PNG",        AV_CODEC_ID_PNG   }, /* ID3v2.2  */
    { "",           AV_CODEC_ID_NONE  },
};

int ff_id3v2_match(const uint8_t *buf, const char *magic)
{
    return  buf[0]         == magic[0] &&
            buf[1]         == magic[1] &&
            buf[2]         == magic[2] &&
            buf[3]         != 0xff     &&
            buf[4]         != 0xff     &&
           (buf[6] & 0x80) == 0        &&
           (buf[7] & 0x80) == 0        &&
           (buf[8] & 0x80) == 0        &&
           (buf[9] & 0x80) == 0;
}

int ff_id3v2_tag_len(const uint8_t *buf)
{
    int len = ((buf[6] & 0x7f) << 21) +
              ((buf[7] & 0x7f) << 14) +
              ((buf[8] & 0x7f) << 7) +
              (buf[9] & 0x7f) +
              ID3v2_HEADER_SIZE;
    if (buf[5] & 0x10)
        len += ID3v2_HEADER_SIZE;
    return len;
}

static unsigned int get_size(AVIOContext *s, int len)
{
    int v = 0;
    while (len--)
        v = (v << 7) + (avio_r8(s) & 0x7F);
    return v;
}

/**
 * Free GEOB type extra metadata.
 */
static void free_geobtag(void *obj)
{
    ID3v2ExtraMetaGEOB *geob = obj;
    av_free(geob->mime_type);
    av_free(geob->file_name);
    av_free(geob->description);
    av_free(geob->data);
    av_free(geob);
}

/**
 * Decode characters to UTF-8 according to encoding type. The decoded buffer is
 * always null terminated. Stop reading when either *maxread bytes are read from
 * pb or U+0000 character is found.
 *
 * @param dst Pointer where the address of the buffer with the decoded bytes is
 * stored. Buffer must be freed by caller.
 * @param maxread Pointer to maximum number of characters to read from the
 * AVIOContext. After execution the value is decremented by the number of bytes
 * actually read.
 * @returns 0 if no error occurred, dst is uninitialized on error
 */
static int decode_str(AVFormatContext *s, AVIOContext *pb, int encoding,
                      uint8_t **dst, int *maxread)
{
    int ret;
    uint8_t tmp;
    uint32_t ch = 1;
    int left = *maxread;
    unsigned int (*get)(AVIOContext*) = avio_rb16;
    AVIOContext *dynbuf;

    if ((ret = avio_open_dyn_buf(&dynbuf)) < 0) {
        av_log(s, AV_LOG_ERROR, "Error opening memory stream\n");
        return ret;
    }

    switch (encoding) {
    case ID3v2_ENCODING_ISO8859:
        while (left && ch) {
            ch = avio_r8(pb);
            PUT_UTF8(ch, tmp, avio_w8(dynbuf, tmp);)
            left--;
        }
        break;

    case ID3v2_ENCODING_UTF16BOM:
        if ((left -= 2) < 0) {
            av_log(s, AV_LOG_ERROR, "Cannot read BOM value, input too short\n");
            ffio_free_dyn_buf(&dynbuf);
            *dst = NULL;
            return AVERROR_INVALIDDATA;
        }
        switch (avio_rb16(pb)) {
        case 0xfffe:
            get = avio_rl16;
        case 0xfeff:
            break;
        default:
            av_log(s, AV_LOG_ERROR, "Incorrect BOM value\n");
            ffio_free_dyn_buf(&dynbuf);
            *dst = NULL;
            *maxread = left;
            return AVERROR_INVALIDDATA;
        }
        // fall-through

    case ID3v2_ENCODING_UTF16BE:
        while ((left > 1) && ch) {
            GET_UTF16(ch, ((left -= 2) >= 0 ? get(pb) : 0), break;)
            PUT_UTF8(ch, tmp, avio_w8(dynbuf, tmp);)
        }
        if (left < 0)
            left += 2;  /* did not read last char from pb */
        break;

    case ID3v2_ENCODING_UTF8:
        while (left && ch) {
            ch = avio_r8(pb);
            avio_w8(dynbuf, ch);
            left--;
        }
        break;
    default:
        av_log(s, AV_LOG_WARNING, "Unknown encoding\n");
    }

    if (ch)
        avio_w8(dynbuf, 0);

    avio_close_dyn_buf(dynbuf, dst);
    *maxread = left;

    return 0;
}

/**
 * Parse a text tag.
 */
static void read_ttag(AVFormatContext *s, AVIOContext *pb, int taglen,
                      const char *key)
{
    uint8_t *dst;
    int encoding, dict_flags = AV_DICT_DONT_OVERWRITE | AV_DICT_DONT_STRDUP_VAL;
    unsigned genre;

    if (taglen < 1)
        return;

    encoding = avio_r8(pb);
    taglen--; /* account for encoding type byte */

    if (decode_str(s, pb, encoding, &dst, &taglen) < 0) {
        av_log(s, AV_LOG_ERROR, "Error reading frame %s, skipped\n", key);
        return;
    }

    if (!(strcmp(key, "TCON") && strcmp(key, "TCO"))                         &&
        (sscanf(dst, "(%d)", &genre) == 1 || sscanf(dst, "%d", &genre) == 1) &&
        genre <= ID3v1_GENRE_MAX) {
        av_freep(&dst);
        dst = av_strdup(ff_id3v1_genre_str[genre]);
    } else if (!(strcmp(key, "TXXX") && strcmp(key, "TXX"))) {
        /* dst now contains the key, need to get value */
        key = dst;
        if (decode_str(s, pb, encoding, &dst, &taglen) < 0) {
            av_log(s, AV_LOG_ERROR, "Error reading frame %s, skipped\n", key);
            av_freep(&key);
            return;
        }
        dict_flags |= AV_DICT_DONT_STRDUP_KEY;
    } else if (!*dst)
        av_freep(&dst);

    if (dst)
        av_dict_set(&s->metadata, key, dst, dict_flags);
}

/**
 * Parse GEOB tag into a ID3v2ExtraMetaGEOB struct.
 */
static void read_geobtag(AVFormatContext *s, AVIOContext *pb, int taglen,
                         const char *tag, ID3v2ExtraMeta **extra_meta,
                         int isv34)
{
    ID3v2ExtraMetaGEOB *geob_data = NULL;
    ID3v2ExtraMeta *new_extra     = NULL;
    char encoding;
    unsigned int len;

    if (taglen < 1)
        return;

    geob_data = av_mallocz(sizeof(ID3v2ExtraMetaGEOB));
    if (!geob_data) {
        av_log(s, AV_LOG_ERROR, "Failed to alloc %zu bytes\n",
               sizeof(ID3v2ExtraMetaGEOB));
        return;
    }

    new_extra = av_mallocz(sizeof(ID3v2ExtraMeta));
    if (!new_extra) {
        av_log(s, AV_LOG_ERROR, "Failed to alloc %zu bytes\n",
               sizeof(ID3v2ExtraMeta));
        goto fail;
    }

    /* read encoding type byte */
    encoding = avio_r8(pb);
    taglen--;

    /* read MIME type (always ISO-8859) */
    if (decode_str(s, pb, ID3v2_ENCODING_ISO8859, &geob_data->mime_type,
                   &taglen) < 0 ||
        taglen <= 0)
        goto fail;

    /* read file name */
    if (decode_str(s, pb, encoding, &geob_data->file_name, &taglen) < 0 ||
        taglen <= 0)
        goto fail;

    /* read content description */
    if (decode_str(s, pb, encoding, &geob_data->description, &taglen) < 0 ||
        taglen < 0)
        goto fail;

    if (taglen) {
        /* save encapsulated binary data */
        geob_data->data = av_malloc(taglen);
        if (!geob_data->data) {
            av_log(s, AV_LOG_ERROR, "Failed to alloc %d bytes\n", taglen);
            goto fail;
        }
        if ((len = avio_read(pb, geob_data->data, taglen)) < taglen)
            av_log(s, AV_LOG_WARNING,
                   "Error reading GEOB frame, data truncated.\n");
        geob_data->datasize = len;
    } else {
        geob_data->data     = NULL;
        geob_data->datasize = 0;
    }

    /* add data to the list */
    new_extra->tag  = "GEOB";
    new_extra->data = geob_data;
    new_extra->next = *extra_meta;
    *extra_meta     = new_extra;

    return;

fail:
    av_log(s, AV_LOG_ERROR, "Error reading frame %s, skipped\n", tag);
    free_geobtag(geob_data);
    av_free(new_extra);
    return;
}

static int is_number(const char *str)
{
    while (*str >= '0' && *str <= '9')
        str++;
    return !*str;
}

static AVDictionaryEntry *get_date_tag(AVDictionary *m, const char *tag)
{
    AVDictionaryEntry *t;
    if ((t = av_dict_get(m, tag, NULL, AV_DICT_MATCH_CASE)) &&
        strlen(t->value) == 4 && is_number(t->value))
        return t;
    return NULL;
}

static void merge_date(AVDictionary **m)
{
    AVDictionaryEntry *t;
    char date[17] = { 0 };      // YYYY-MM-DD hh:mm

    if (!(t = get_date_tag(*m, "TYER")) &&
        !(t = get_date_tag(*m, "TYE")))
        return;
    av_strlcpy(date, t->value, 5);
    av_dict_set(m, "TYER", NULL, 0);
    av_dict_set(m, "TYE", NULL, 0);

    if (!(t = get_date_tag(*m, "TDAT")) &&
        !(t = get_date_tag(*m, "TDA")))
        goto finish;
    snprintf(date + 4, sizeof(date) - 4, "-%.2s-%.2s", t->value + 2, t->value);
    av_dict_set(m, "TDAT", NULL, 0);
    av_dict_set(m, "TDA", NULL, 0);

    if (!(t = get_date_tag(*m, "TIME")) &&
        !(t = get_date_tag(*m, "TIM")))
        goto finish;
    snprintf(date + 10, sizeof(date) - 10,
             " %.2s:%.2s", t->value, t->value + 2);
    av_dict_set(m, "TIME", NULL, 0);
    av_dict_set(m, "TIM", NULL, 0);

finish:
    if (date[0])
        av_dict_set(m, "date", date, 0);
}

static void free_apic(void *obj)
{
    ID3v2ExtraMetaAPIC *apic = obj;
    av_buffer_unref(&apic->buf);
    av_freep(&apic->description);
    av_freep(&apic);
}

static void read_apic(AVFormatContext *s, AVIOContext *pb, int taglen,
                      const char *tag, ID3v2ExtraMeta **extra_meta,
                      int isv34)
{
    int enc, pic_type;
    char mimetype[64];
    const CodecMime *mime     = ff_id3v2_mime_tags;
    enum AVCodecID id         = AV_CODEC_ID_NONE;
    ID3v2ExtraMetaAPIC *apic  = NULL;
    ID3v2ExtraMeta *new_extra = NULL;
    int64_t end               = avio_tell(pb) + taglen;

    if (taglen <= 4 || (!isv34 && taglen <= 6))
        goto fail;

    new_extra = av_mallocz(sizeof(*new_extra));
    apic      = av_mallocz(sizeof(*apic));
    if (!new_extra || !apic)
        goto fail;

    enc = avio_r8(pb);
    taglen--;

    /* mimetype */
    if (isv34) {
        taglen -= avio_get_str(pb, taglen, mimetype, sizeof(mimetype));
    } else {
        avio_read(pb, mimetype, 3);
        mimetype[3] = 0;
        taglen    -= 3;
    }

    while (mime->id != AV_CODEC_ID_NONE) {
        if (!av_strncasecmp(mime->str, mimetype, sizeof(mimetype))) {
            id = mime->id;
            break;
        }
        mime++;
    }
    if (id == AV_CODEC_ID_NONE) {
        av_log(s, AV_LOG_WARNING,
               "Unknown attached picture mimetype: %s, skipping.\n", mimetype);
        goto fail;
    }
    apic->id = id;

    /* picture type */
    pic_type = avio_r8(pb);
    taglen--;
    if (pic_type < 0 || pic_type >= FF_ARRAY_ELEMS(ff_id3v2_picture_types)) {
        av_log(s, AV_LOG_WARNING, "Unknown attached picture type %d.\n",
               pic_type);
        pic_type = 0;
    }
    apic->type = ff_id3v2_picture_types[pic_type];

    /* description and picture data */
    if (decode_str(s, pb, enc, &apic->description, &taglen) < 0) {
        av_log(s, AV_LOG_ERROR,
               "Error decoding attached picture description.\n");
        goto fail;
    }

    apic->buf = av_buffer_alloc(taglen + FF_INPUT_BUFFER_PADDING_SIZE);
    if (!apic->buf || avio_read(pb, apic->buf->data, taglen) != taglen)
        goto fail;
    memset(apic->buf->data + taglen, 0, FF_INPUT_BUFFER_PADDING_SIZE);

    new_extra->tag  = "APIC";
    new_extra->data = apic;
    new_extra->next = *extra_meta;
    *extra_meta     = new_extra;

    return;

fail:
    if (apic)
        free_apic(apic);
    av_freep(&new_extra);
    avio_seek(pb, end, SEEK_SET);
}

typedef struct ID3v2EMFunc {
    const char *tag3;
    const char *tag4;
    void (*read)(AVFormatContext *s, AVIOContext *pb, int taglen,
                 const char *tag, ID3v2ExtraMeta **extra_meta,
                 int isv34);
    void (*free)(void *obj);
} ID3v2EMFunc;

static const ID3v2EMFunc id3v2_extra_meta_funcs[] = {
    { "GEO", "GEOB", read_geobtag, free_geobtag },
    { "PIC", "APIC", read_apic,    free_apic    },
    { NULL }
};

/**
 * Get the corresponding ID3v2EMFunc struct for a tag.
 * @param isv34 Determines if v2.2 or v2.3/4 strings are used
 * @return A pointer to the ID3v2EMFunc struct if found, NULL otherwise.
 */
static const ID3v2EMFunc *get_extra_meta_func(const char *tag, int isv34)
{
    int i = 0;
    while (id3v2_extra_meta_funcs[i].tag3) {
        if (!memcmp(tag,
                    (isv34 ? id3v2_extra_meta_funcs[i].tag4 :
                             id3v2_extra_meta_funcs[i].tag3),
                    (isv34 ? 4 : 3)))
            return &id3v2_extra_meta_funcs[i];
        i++;
    }
    return NULL;
}

static void id3v2_parse(AVFormatContext *s, int len, uint8_t version,
                        uint8_t flags, ID3v2ExtraMeta **extra_meta)
{
    int isv34, tlen, unsync;
    char tag[5];
    int64_t next, end = avio_tell(s->pb) + len;
    int taghdrlen;
    const char *reason = NULL;
    AVIOContext pb;
    AVIOContext *pbx;
    unsigned char *buffer = NULL;
    int buffer_size       = 0;
    const ID3v2EMFunc *extra_func;

    switch (version) {
    case 2:
        if (flags & 0x40) {
            reason = "compression";
            goto error;
        }
        isv34     = 0;
        taghdrlen = 6;
        break;

    case 3:
    case 4:
        isv34     = 1;
        taghdrlen = 10;
        break;

    default:
        reason = "version";
        goto error;
    }

    unsync = flags & 0x80;

    if (isv34 && flags & 0x40) { /* Extended header present, just skip over it */
        int extlen = get_size(s->pb, 4);
        if (version == 4)
            /* In v2.4 the length includes the length field we just read. */
            extlen -= 4;

        if (extlen < 0) {
            reason = "invalid extended header length";
            goto error;
        }
        avio_skip(s->pb, extlen);
    }

    while (len >= taghdrlen) {
        unsigned int tflags = 0;
        int tunsync         = 0;

        if (isv34) {
            avio_read(s->pb, tag, 4);
            tag[4] = 0;
            if (version == 3) {
                tlen = avio_rb32(s->pb);
            } else
                tlen = get_size(s->pb, 4);
            tflags  = avio_rb16(s->pb);
            tunsync = tflags & ID3v2_FLAG_UNSYNCH;
        } else {
            avio_read(s->pb, tag, 3);
            tag[3] = 0;
            tlen   = avio_rb24(s->pb);
        }
        if (tlen < 0 || tlen > len - taghdrlen) {
            av_log(s, AV_LOG_WARNING,
                   "Invalid size in frame %s, skipping the rest of tag.\n",
                   tag);
            break;
        }
        len -= taghdrlen + tlen;
        next = avio_tell(s->pb) + tlen;

        if (!tlen) {
            if (tag[0])
                av_log(s, AV_LOG_DEBUG, "Invalid empty frame %s, skipping.\n",
                       tag);
            continue;
        }

        if (tflags & ID3v2_FLAG_DATALEN) {
            avio_rb32(s->pb);
            tlen -= 4;
        }

        if (tflags & (ID3v2_FLAG_ENCRYPTION | ID3v2_FLAG_COMPRESSION)) {
            av_log(s, AV_LOG_WARNING,
                   "Skipping encrypted/compressed ID3v2 frame %s.\n", tag);
            avio_skip(s->pb, tlen);
        /* check for text tag or supported special meta tag */
        } else if (tag[0] == 'T' ||
                   (extra_meta &&
                    (extra_func = get_extra_meta_func(tag, isv34)))) {
            if (unsync || tunsync) {
                int64_t end = avio_tell(s->pb) + tlen;
                uint8_t *b;
                av_fast_malloc(&buffer, &buffer_size, tlen);
                if (!buffer) {
                    av_log(s, AV_LOG_ERROR, "Failed to alloc %d bytes\n", tlen);
                    goto seek;
                }
                b = buffer;
                while (avio_tell(s->pb) < end && !s->pb->eof_reached) {
                    *b++ = avio_r8(s->pb);
                    if (*(b - 1) == 0xff && avio_tell(s->pb) < end - 1 &&
                        !s->pb->eof_reached ) {
                        uint8_t val = avio_r8(s->pb);
                        *b++ = val ? val : avio_r8(s->pb);
                    }
                }
                ffio_init_context(&pb, buffer, b - buffer, 0, NULL, NULL, NULL,
                                  NULL);
                tlen = b - buffer;
                pbx  = &pb; // read from sync buffer
            } else {
                pbx = s->pb; // read straight from input
            }
            if (tag[0] == 'T')
                /* parse text tag */
                read_ttag(s, pbx, tlen, tag);
            else
                /* parse special meta tag */
                extra_func->read(s, pbx, tlen, tag, extra_meta, isv34);
        } else if (!tag[0]) {
            if (tag[1])
                av_log(s, AV_LOG_WARNING, "invalid frame id, assuming padding");
            avio_skip(s->pb, tlen);
            break;
        }
        /* Skip to end of tag */
seek:
        avio_seek(s->pb, next, SEEK_SET);
    }

    /* Footer preset, always 10 bytes, skip over it */
    if (version == 4 && flags & 0x10)
        end += 10;

error:
    if (reason)
        av_log(s, AV_LOG_INFO, "ID3v2.%d tag skipped, cannot handle %s\n",
               version, reason);
    avio_seek(s->pb, end, SEEK_SET);
    av_free(buffer);
    return;
}

void ff_id3v2_read(AVFormatContext *s, const char *magic,
                   ID3v2ExtraMeta **extra_meta)
{
    int len, ret;
    uint8_t buf[ID3v2_HEADER_SIZE];
    int found_header;
    int64_t off;

    do {
        /* save the current offset in case there's nothing to read/skip */
        off = avio_tell(s->pb);
        ret = avio_read(s->pb, buf, ID3v2_HEADER_SIZE);
        if (ret != ID3v2_HEADER_SIZE)
            break;
        found_header = ff_id3v2_match(buf, magic);
        if (found_header) {
            /* parse ID3v2 header */
            len = ((buf[6] & 0x7f) << 21) |
                  ((buf[7] & 0x7f) << 14) |
                  ((buf[8] & 0x7f) << 7) |
                   (buf[9] & 0x7f);
            id3v2_parse(s, len, buf[3], buf[5], extra_meta);
        } else {
            avio_seek(s->pb, off, SEEK_SET);
        }
    } while (found_header);
    ff_metadata_conv(&s->metadata, NULL, ff_id3v2_34_metadata_conv);
    ff_metadata_conv(&s->metadata, NULL, id3v2_2_metadata_conv);
    ff_metadata_conv(&s->metadata, NULL, ff_id3v2_4_metadata_conv);
    merge_date(&s->metadata);
}

void ff_id3v2_free_extra_meta(ID3v2ExtraMeta **extra_meta)
{
    ID3v2ExtraMeta *current = *extra_meta, *next;
    const ID3v2EMFunc *extra_func;

    while (current) {
        if ((extra_func = get_extra_meta_func(current->tag, 1)))
            extra_func->free(current->data);
        next = current->next;
        av_freep(&current);
        current = next;
    }
}

int ff_id3v2_parse_apic(AVFormatContext *s, ID3v2ExtraMeta **extra_meta)
{
    ID3v2ExtraMeta *cur;

    for (cur = *extra_meta; cur; cur = cur->next) {
        ID3v2ExtraMetaAPIC *apic;
        AVStream *st;

        if (strcmp(cur->tag, "APIC"))
            continue;
        apic = cur->data;

        if (!(st = avformat_new_stream(s, NULL)))
            return AVERROR(ENOMEM);

        st->disposition      |= AV_DISPOSITION_ATTACHED_PIC;
        st->codec->codec_type = AVMEDIA_TYPE_VIDEO;
        st->codec->codec_id   = apic->id;
        av_dict_set(&st->metadata, "title",   apic->description, 0);
        av_dict_set(&st->metadata, "comment", apic->type, 0);

        av_init_packet(&st->attached_pic);
        st->attached_pic.buf          = apic->buf;
        st->attached_pic.data         = apic->buf->data;
        st->attached_pic.size         = apic->buf->size - FF_INPUT_BUFFER_PADDING_SIZE;
        st->attached_pic.stream_index = st->index;
        st->attached_pic.flags       |= AV_PKT_FLAG_KEY;

        apic->buf = NULL;
    }

    return 0;
}