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https://github.com/librempeg/librempeg
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89 lines
2.4 KiB
Plaintext
89 lines
2.4 KiB
Plaintext
@chapter Metadata
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@c man begin METADATA
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FFmpeg is able to dump metadata from media files into a simple UTF-8-encoded
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INI-like text file and then load it back using the metadata muxer/demuxer.
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The file format is as follows:
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@enumerate
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@item
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A file consists of a header and a number of metadata tags divided into sections,
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each on its own line.
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@item
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The header is a @samp{;FFMETADATA} string, followed by a version number (now 1).
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@item
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Metadata tags are of the form @samp{key=value}
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@item
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Immediately after header follows global metadata
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@item
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After global metadata there may be sections with per-stream/per-chapter
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metadata.
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@item
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A section starts with the section name in uppercase (i.e. STREAM or CHAPTER) in
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brackets (@samp{[}, @samp{]}) and ends with next section or end of file.
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@item
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At the beginning of a chapter section there may be an optional timebase to be
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used for start/end values. It must be in form
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@samp{TIMEBASE=@var{num}/@var{den}}, where @var{num} and @var{den} are
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integers. If the timebase is missing then start/end times are assumed to
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be in nanoseconds.
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Next a chapter section must contain chapter start and end times in form
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@samp{START=@var{num}}, @samp{END=@var{num}}, where @var{num} is a positive
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integer.
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@item
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Empty lines and lines starting with @samp{;} or @samp{#} are ignored.
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@item
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Metadata keys or values containing special characters (@samp{=}, @samp{;},
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@samp{#}, @samp{\} and a newline) must be escaped with a backslash @samp{\}.
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@item
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Note that whitespace in metadata (e.g. @samp{foo = bar}) is considered to be
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a part of the tag (in the example above key is @samp{foo }, value is
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@samp{ bar}).
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@end enumerate
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A ffmetadata file might look like this:
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@example
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;FFMETADATA1
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title=bike\\shed
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;this is a comment
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artist=FFmpeg troll team
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[CHAPTER]
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TIMEBASE=1/1000
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START=0
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#chapter ends at 0:01:00
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END=60000
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title=chapter \#1
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[STREAM]
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title=multi\
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line
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@end example
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By using the ffmetadata muxer and demuxer it is possible to extract
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metadata from an input file to an ffmetadata file, and then transcode
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the file into an output file with the edited ffmetadata file.
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Extracting an ffmetadata file with @file{ffmpeg} goes as follows:
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@example
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ffmpeg -i INPUT -f ffmetadata FFMETADATAFILE
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@end example
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Reinserting edited metadata information from the FFMETADATAFILE file can
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be done as:
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@example
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ffmpeg -i INPUT -i FFMETADATAFILE -map_metadata 1 -codec copy OUTPUT
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@end example
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@c man end METADATA
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