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FFmpeg/libavformat/id3v2.h
Andreas Rheinhardt 8068f2fcf3 avformat/id3v2: Don't reverse the order of id3v2 APICs
When parsing ID3v2 tags, special (non-text) metadata is not applied
directly and unconditionally; instead it is stored in a linked list
in which elements are prepended. When traversing the list to add APICs
(or private tags) at the end, the order is reversed. The same also
happens for chapters and therefore the chapter parsing code already
reverses the chapters.

This commit changes this: By keeping pointers to both head and tail
of the linked list one can preserve the order of the entries and
remove the reordering code for chapters. Only the pointer to head
will be exported: No current caller uses a nonempty list, so exporting
both head and tail is unnecessary. This removes the functionality
to combine the lists of special metadata read from different ID3v2 tags,
but that doesn't make really much sense anyway (and would be trivial
to implement if desired) and allows to remove the now unnecessary
initializations performed by the callers.

The FATE-reference for the id3v2-priv test had to be updated
because the order of the tags read into the dict is reversed;
for id3v2-priv-remux only the md5 and not the ffprobe output
of the remuxed file changes because the order of the private tags
has up until now been reversed twice.

The references for the aiff/mp3 cover-art tests needed to be updated,
because the order of the attached pics is reversed upon reading.
It is still not correct, because the muxers write the pics in the order
in which they arrive at the muxer instead of the order given by
pkt->stream_index.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
2021-04-18 02:24:44 +02:00

215 lines
6.3 KiB
C

/*
* ID3v2 header parser
* 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
*/
#ifndef AVFORMAT_ID3V2_H
#define AVFORMAT_ID3V2_H
#include <stdint.h>
#include "avformat.h"
#include "internal.h"
#include "metadata.h"
#define ID3v2_HEADER_SIZE 10
/**
* Default magic bytes for ID3v2 header: "ID3"
*/
#define ID3v2_DEFAULT_MAGIC "ID3"
#define ID3v2_FLAG_DATALEN 0x0001
#define ID3v2_FLAG_UNSYNCH 0x0002
#define ID3v2_FLAG_ENCRYPTION 0x0004
#define ID3v2_FLAG_COMPRESSION 0x0008
#define ID3v2_PRIV_METADATA_PREFIX "id3v2_priv."
enum ID3v2Encoding {
ID3v2_ENCODING_ISO8859 = 0,
ID3v2_ENCODING_UTF16BOM = 1,
ID3v2_ENCODING_UTF16BE = 2,
ID3v2_ENCODING_UTF8 = 3,
};
typedef struct ID3v2EncContext {
int version; ///< ID3v2 minor version, either 3 or 4
int64_t size_pos; ///< offset of the tag total size
int len; ///< size of the tag written so far
} ID3v2EncContext;
typedef struct ID3v2ExtraMetaGEOB {
uint32_t datasize;
uint8_t *mime_type;
uint8_t *file_name;
uint8_t *description;
uint8_t *data;
} ID3v2ExtraMetaGEOB;
typedef struct ID3v2ExtraMetaAPIC {
AVBufferRef *buf;
const char *type;
uint8_t *description;
enum AVCodecID id;
} ID3v2ExtraMetaAPIC;
typedef struct ID3v2ExtraMetaPRIV {
uint8_t *owner;
uint8_t *data;
uint32_t datasize;
} ID3v2ExtraMetaPRIV;
typedef struct ID3v2ExtraMetaCHAP {
uint8_t *element_id;
uint32_t start, end;
AVDictionary *meta;
} ID3v2ExtraMetaCHAP;
typedef struct ID3v2ExtraMeta {
const char *tag;
struct ID3v2ExtraMeta *next;
union {
ID3v2ExtraMetaAPIC apic;
ID3v2ExtraMetaCHAP chap;
ID3v2ExtraMetaGEOB geob;
ID3v2ExtraMetaPRIV priv;
} data;
} ID3v2ExtraMeta;
/**
* Detect ID3v2 Header.
* @param buf must be ID3v2_HEADER_SIZE byte long
* @param magic magic bytes to identify the header.
* If in doubt, use ID3v2_DEFAULT_MAGIC.
*/
int ff_id3v2_match(const uint8_t *buf, const char *magic);
/**
* Get the length of an ID3v2 tag.
* @param buf must be ID3v2_HEADER_SIZE bytes long and point to the start of an
* already detected ID3v2 tag
*/
int ff_id3v2_tag_len(const uint8_t *buf);
/**
* Read an ID3v2 tag into specified dictionary and retrieve supported extra metadata.
*
* @param metadata Parsed metadata is stored here
* @param[out] extra_meta If not NULL, extra metadata is parsed into a list of
* ID3v2ExtraMeta structs and *extra_meta points to the head of the list
*/
void ff_id3v2_read_dict(AVIOContext *pb, AVDictionary **metadata, const char *magic, ID3v2ExtraMeta **extra_meta);
/**
* Read an ID3v2 tag, including supported extra metadata.
*
* Data is read from and stored to AVFormatContext.
*
* @param[out] extra_meta If not NULL, extra metadata is parsed into a list of
* ID3v2ExtraMeta structs and *extra_meta points to the head of the list
* @param[opt] max_search_search restrict ID3 magic number search (bytes from start)
*/
void ff_id3v2_read(AVFormatContext *s, const char *magic, ID3v2ExtraMeta **extra_meta,
unsigned int max_search_size);
/**
* Initialize an ID3v2 tag.
*/
void ff_id3v2_start(ID3v2EncContext *id3, AVIOContext *pb, int id3v2_version,
const char *magic);
/**
* Convert and write all global metadata from s into an ID3v2 tag.
*/
int ff_id3v2_write_metadata(AVFormatContext *s, ID3v2EncContext *id3);
/**
* Write an attached picture from pkt into an ID3v2 tag.
*/
int ff_id3v2_write_apic(AVFormatContext *s, ID3v2EncContext *id3, AVPacket *pkt);
/**
* Finalize an opened ID3v2 tag.
*/
void ff_id3v2_finish(ID3v2EncContext *id3, AVIOContext *pb, int padding_bytes);
/**
* Write an ID3v2 tag containing all global metadata from s.
* @param id3v2_version Subversion of ID3v2; supported values are 3 and 4
* @param magic magic bytes to identify the header
* If in doubt, use ID3v2_DEFAULT_MAGIC.
*/
int ff_id3v2_write_simple(struct AVFormatContext *s, int id3v2_version, const char *magic);
/**
* Free memory allocated parsing special (non-text) metadata.
* @param extra_meta Pointer to a pointer to the head of a ID3v2ExtraMeta list, *extra_meta is set to NULL.
*/
void ff_id3v2_free_extra_meta(ID3v2ExtraMeta **extra_meta);
/**
* Create a stream for each APIC (attached picture) extracted from the
* ID3v2 header.
*/
int ff_id3v2_parse_apic(AVFormatContext *s, ID3v2ExtraMeta *extra_meta);
/**
* Create chapters for all CHAP tags found in the ID3v2 header.
*/
int ff_id3v2_parse_chapters(AVFormatContext *s, ID3v2ExtraMeta *extra_meta);
/**
* Parse PRIV tags into a dictionary. The PRIV owner is the metadata key. The
* PRIV data is the value, with non-printable characters escaped.
*/
int ff_id3v2_parse_priv_dict(AVDictionary **d, ID3v2ExtraMeta *extra_meta);
/**
* Add metadata for all PRIV tags in the ID3v2 header. The PRIV owner is the
* metadata key. The PRIV data is the value, with non-printable characters
* escaped.
*/
int ff_id3v2_parse_priv(AVFormatContext *s, ID3v2ExtraMeta *extra_meta);
extern const AVMetadataConv ff_id3v2_34_metadata_conv[];
extern const AVMetadataConv ff_id3v2_4_metadata_conv[];
/**
* A list of text information frames allowed in both ID3 v2.3 and v2.4
* http://www.id3.org/id3v2.4.0-frames
* http://www.id3.org/id3v2.4.0-changes
*/
extern const char ff_id3v2_tags[][4];
/**
* ID3v2.4-only text information frames.
*/
extern const char ff_id3v2_4_tags[][4];
/**
* ID3v2.3-only text information frames.
*/
extern const char ff_id3v2_3_tags[][4];
extern const CodecMime ff_id3v2_mime_tags[];
extern const char * const ff_id3v2_picture_types[21];
#endif /* AVFORMAT_ID3V2_H */