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mirror of https://github.com/mpv-player/mpv synced 2024-09-12 23:45:53 +02:00
mpv/common/tags.h
wm4 e7e06a47a0 demux: support for some kinds of timed metadata
This makes ICY title changes show up at approximately the correct time,
even if the demuxer buffer is huge. (It'll still be wrong if the stream
byte cache contains a meaningful amount of data.)

It should have the same effect for mid-stream metadata changes in e.g.
OGG (untested).

This is still somewhat fishy, but in parts due to ICY being fishy, and
FFmpeg's metadata change API being somewhat fishy. For example, what
happens if you seek? With FFmpeg AVFMT_EVENT_FLAG_METADATA_UPDATED and
AVSTREAM_EVENT_FLAG_METADATA_UPDATED we hope that FFmpeg will correctly
restore the correct metadata when the first packet is returned.

If you seke with ICY, we're out of luck, and some audio will be
associated with the wrong tag until we get a new title through ICY
metadata update at an essentially random point (it's mostly inherent to
ICY). Then the tags will switch back and forth, and this behavior will
stick with the data stored in the demuxer cache. Fortunately, this can
happen only if the HTTP stream is actually seekable, which it usually is
not for ICY things. Seeking doesn't even make sense with ICY, since you
can't know the exact metadata location. Basically ICY metsdata sucks.

Some complexity is due to a microoptimization: I didn't want additional
atomic accesses for each packet if no timed metadata is used. (It
probably doesn't matter at all.)
2018-04-18 01:17:42 +03:00

30 lines
1019 B
C

#ifndef MP_TAGS_H
#define MP_TAGS_H
#include <stdint.h>
#include "misc/bstr.h"
struct mp_tags {
char **keys;
char **values;
int num_keys;
};
void mp_tags_set_str(struct mp_tags *tags, const char *key, const char *value);
void mp_tags_set_bstr(struct mp_tags *tags, bstr key, bstr value);
void mp_tags_remove_str(struct mp_tags *tags, const char *key);
void mp_tags_remove_bstr(struct mp_tags *tags, bstr key);
char *mp_tags_get_str(struct mp_tags *tags, const char *key);
char *mp_tags_get_bstr(struct mp_tags *tags, bstr key);
void mp_tags_clear(struct mp_tags *tags);
struct mp_tags *mp_tags_dup(void *tparent, struct mp_tags *tags);
void mp_tags_replace(struct mp_tags *dst, struct mp_tags *src);
struct mp_tags *mp_tags_filtered(void *tparent, struct mp_tags *tags, char **list);
void mp_tags_merge(struct mp_tags *tags, struct mp_tags *src);
struct AVDictionary;
void mp_tags_copy_from_av_dictionary(struct mp_tags *tags,
struct AVDictionary *av_dict);
#endif