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/*

 * Copyright (c) 2003 Fabrice Bellard

 *

 * This file is part of FFmpeg.

 *

 * FFmpeg 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.

 *

 * FFmpeg 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 FFmpeg; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

 */

/**

 * @file

 * ID3v2 header parser

 *

 * Specifications available at:

 * http://id3.org/Developer_Information

 */

#include "config.h"

#if CONFIG_ZLIB

#include 

#endif

#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");

            avio_close_dyn_buf(dynbuf, dst);

            av_freep(dst);

            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");

            avio_close_dyn_buf(dynbuf, dst);

            av_freep(dst);

            *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,

                      AVDictionary **metadata, 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(metadata, key, dst, dict_flags);

}

/**

 * Parse GEOB tag into a ID3v2ExtraMetaGEOB struct.

 */

static void read_geobtag(AVFormatContext *s, AVIOContext *pb, int taglen,

                         char *tag, ID3v2ExtraMeta **extra_meta)

{

    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,

                      char *tag, ID3v2ExtraMeta **extra_meta)

{

    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)

        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 */

    taglen -= avio_get_str(pb, taglen, mimetype, sizeof(mimetype));

    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 || !taglen || 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);

}

static void read_chapter(AVFormatContext *s, AVIOContext *pb, int len, char *ttag, ID3v2ExtraMeta **extra_meta)

{

    AVRational time_base = {1, 1000};

    uint32_t start, end;

    AVChapter *chapter;

    uint8_t *dst = NULL;

    int taglen;

    char tag[5];

    if (decode_str(s, pb, 0, &dst, &len) < 0)

        return;

    if (len < 16)

        return;

    start = avio_rb32(pb);

    end   = avio_rb32(pb);

    avio_skip(pb, 8);

    chapter = avpriv_new_chapter(s, s->nb_chapters + 1, time_base, start, end, dst);

    if (!chapter) {

        av_free(dst);

        return;

    }

    len -= 16;

    while (len > 10) {

        avio_read(pb, tag, 4);

        tag[4] = 0;

        taglen = avio_rb32(pb);

        avio_skip(pb, 2);

        len -= 10;

        if (taglen < 0 || taglen > len) {

            av_free(dst);

            return;

        }

        if (tag[0] == 'T')

            read_ttag(s, pb, taglen, &chapter->metadata, tag);

        else

            avio_skip(pb, taglen);

        len -= taglen;

    }

    ff_metadata_conv(&chapter->metadata, NULL, ff_id3v2_34_metadata_conv);

    ff_metadata_conv(&chapter->metadata, NULL, ff_id3v2_4_metadata_conv);

    av_free(dst);

}

typedef struct ID3v2EMFunc {

    const char *tag3;

    const char *tag4;

    void (*read)(AVFormatContext *, AVIOContext *, int, char *,

                 ID3v2ExtraMeta **);

    void (*free)(void *obj);

} ID3v2EMFunc;

static const ID3v2EMFunc id3v2_extra_meta_funcs[] = {

    { "GEO", "GEOB", read_geobtag, free_geobtag },

    { "PIC", "APIC", read_apic,    free_apic    },

    { "CHAP","CHAP", read_chapter, NULL         },

    { 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 (tag && !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, unsync;

    unsigned tlen;

    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 = NULL;

    unsigned char *uncompressed_buffer = NULL;

    int uncompressed_buffer_size = 0;

    av_log(s, AV_LOG_DEBUG, "id3v2 ver:%d flags:%02X len:%d\n", version, flags, len);

    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);

        len -= extlen + 4;

        if (len < 0) {

            reason = "extended header too long.";

            goto error;

        }

    }

    while (len >= taghdrlen) {

        unsigned int tflags = 0;

        int tunsync         = 0;

        int tcomp           = 0;

        int tencr           = 0;

        unsigned long dlen;

        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 > (1<<28))

            break;

        len -= taghdrlen + tlen;

        if (len < 0)

            break;

        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) {

            if (tlen < 4)

                break;

            dlen = avio_rb32(s->pb);

            tlen -= 4;

        } else

            dlen = tlen;

        tcomp = tflags & ID3v2_FLAG_COMPRESSION;

        tencr = tflags & ID3v2_FLAG_ENCRYPTION;

        /* skip encrypted tags and, if no zlib, compressed tags */

        if (tencr || (!CONFIG_ZLIB && tcomp)) {

            const char *type;

            if (!tcomp)

                type = "encrypted";

            else if (!tencr)

                type = "compressed";

            else

                type = "encrypted and compressed";

            av_log(s, AV_LOG_WARNING, "Skipping %s ID3v2 frame %s.\n", type, 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)))) {

            pbx = s->pb;

            if (unsync || tunsync || tcomp) {

                av_fast_malloc(&buffer, &buffer_size, tlen);

                if (!buffer) {

                    av_log(s, AV_LOG_ERROR, "Failed to alloc %d bytes\n", tlen);

                    goto seek;

                }

            }

            if (unsync || tunsync) {

                int64_t end = avio_tell(s->pb) + tlen;

                uint8_t *b;

                b = buffer;

                while (avio_tell(s->pb) < end && b - buffer < tlen && !s->pb->eof_reached) {

                    *b++ = avio_r8(s->pb);

                    if (*(b - 1) == 0xff && avio_tell(s->pb) < end - 1 &&

                        b - buffer < tlen &&

                        !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

            }

#if CONFIG_ZLIB

                if (tcomp) {

                    int err;

                    av_log(s, AV_LOG_DEBUG, "Compresssed frame %s tlen=%d dlen=%ld\n", tag, tlen, dlen);

                    av_fast_malloc(&uncompressed_buffer, &uncompressed_buffer_size, dlen);

                    if (!uncompressed_buffer) {

                        av_log(s, AV_LOG_ERROR, "Failed to alloc %ld bytes\n", dlen);

                        goto seek;

                    }

                    if (!(unsync || tunsync)) {

                        err = avio_read(s->pb, buffer, tlen);

                        if (err < 0) {

                            av_log(s, AV_LOG_ERROR, "Failed to read compressed tag\n");

                            goto seek;

                        }

                        tlen = err;

                    }

                    err = uncompress(uncompressed_buffer, &dlen, buffer, tlen);

                    if (err != Z_OK) {

                        av_log(s, AV_LOG_ERROR, "Failed to uncompress tag: %d\n", err);

                        goto seek;

                    }

                    ffio_init_context(&pb, uncompressed_buffer, dlen, 0, NULL, NULL, NULL, NULL);

                    tlen = dlen;

                    pbx = &pb; // read from sync buffer

                }

#endif

            if (tag[0] == 'T')

                /* parse text tag */

                read_ttag(s, pbx, tlen, &s->metadata, tag);

            else

                /* parse special meta tag */

                extra_func->read(s, pbx, tlen, tag, extra_meta);

        } else if (!tag[0]) {

            if (tag[1])

                av_log(s, AV_LOG_WARNING, "invalid frame id, assuming padding\n");

            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);

    av_free(uncompressed_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) {

            avio_seek(s->pb, off, SEEK_SET);

            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(¤t);

        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;

}