FFmpeg/doc/metadata.texi

@chapter Metadata
@c man begin METADATA

Libav is able to dump metadata from media files into a simple UTF-8-encoded
INI-like text file and then load it back using the metadata muxer/demuxer.

The file format is as follows:
@enumerate

@item
A file consists of a header and a number of metadata tags divided into sections,
each on its own line.

@item
The header is a ';FFMETADATA' string, followed by a version number (now 1).

@item
Metadata tags are of the form 'key=value'

@item
Immediately after header follows global metadata

@item
After global metadata there may be sections with per-stream/per-chapter
metadata.

@item
A section starts with the section name in uppercase (i.e. STREAM or CHAPTER) in
brackets ('[', ']') and ends with next section or end of file.

@item
At the beginning of a chapter section there may be an optional timebase to be
used for start/end values. It must be in form 'TIMEBASE=num/den', where num and
den are integers. If the timebase is missing then start/end times are assumed to
be in milliseconds.
Next a chapter section must contain chapter start and end times in form
'START=num', 'END=num', where num is a positive integer.

@item
Empty lines and lines starting with ';' or '#' are ignored.

@item
Metadata keys or values containing special characters ('=', ';', '#', '\' and a
newline) must be escaped with a backslash '\'.

@item
Note that whitespace in metadata (e.g. foo = bar) is considered to be a part of
the tag (in the example above key is 'foo ', value is ' bar').
@end enumerate

A ffmetadata file might look like this:
@example
;FFMETADATA1
title=bike\\shed
;this is a comment
artist=Libav troll team

[CHAPTER]
TIMEBASE=1/1000
START=0
#chapter ends at 0:01:00
END=60000
title=chapter \#1
[STREAM]
title=multi\
line
@end example
@c man end METADATA