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{{Short description|Metadata container for Ogg file formats}}
A '''Vorbis comment''' is a ] container used in the ], ], ], ] and ] ]s. It allows information such as the title, artist, album, track number or other information about the file to be added to the file itself. However, as the official Ogg Vorbis documentation notes:<ref>, with suggestions for field names</ref>
]]]
A '''Vorbis comment''' is a ] container used in the ] file format (with ], ], ], ] and ] ]s).<ref>{{cite IETF |rfc=7845 |title=Ogg Encapsulation for the Opus Audio Codec |section=5.2.1 |sectionname=Tag Definitions |author=T. Terriberry |display-authors=etal |year=2016 |publisher = ] |doi=10.17487/RFC7845}}</ref> It allows information such as the title, artist, album, track number or other information about the file to be added to the file itself. However, as the official Ogg Vorbis documentation notes, “ is meant for short, text comments, not arbitrary metadata; arbitrary metadata belongs in a separate logical bitstream (usually an XML stream type) that provides greater structure and machine parseability.” Instead, the intended function of Vorbis comments is to approximate the kind of information that might be hand-inked onto a blank faced ] or ]: a few lines of notes briefly detailing the content.<ref>{{Cite web|title=Ogg Vorbis I format specification: comment field and header specification|url=http://www.xiph.org/vorbis/doc/v-comment.html|website=xiph.org|publisher=Xiph.Org Foundation|year=2005|access-date=18 February 2016}}</ref>


⚫ ==Format==
{{cquote| is meant for short, text comments, not arbitrary metadata; arbitrary metadata belongs in a separate logical bitstream (usually an XML stream type) that provides greater structure and machine parseability.}}
⚫ A Vorbis tag is a list of fields in the format <code>FieldName=Data</code>. The field name can be composed of printable ] characters, 0x20 (''space'') through 0x7D (‘}’), with 0x3D (‘=’) and 0x7E (‘~’) excluded. It is case insensitive, so <code>artist</code> and <code>ARTIST</code> are the same field.


The number of fields and their length is restricted to 4,294,967,295 (the maximum value of an unsigned 32-] ]), but most tag editing applications impose stricter limits. ] has a smaller limit of 24-] in a <kbd>METADATA_BLOCK_VORBIS_COMMENT</kbd>, because it stores thumbnails and cover art in binary ] <kbd>METADATA_BLOCK_PICTURE</kbd>s outside of the FLAC tags.<ref>{{cite web |url=https://xiph.org/flac/format.html#metadata_block_vorbis_comment |title=METADATA_BLOCK_VORBIS_COMMENT |work=flac free lossless audio codec |publisher=] |year=2014 |access-date=2019-12-03}}</ref>
⚫ == Format ==


⚫ The data is encoded in ], and so any conforming ] string may be used as a value.
⚫ A Vorbis tag is a list of fields in the format <code>FieldName=Data</code>. The field name can be composed of printable ] characters, 0x20 (space) through 0x7D ('}'), with 0x3D ('=') and 0x7E ('~') excluded. It is case insensitive, so <code>artist</code> and <code>ARTIST</code> are the same field. The number of fields and their length is restricted to 4,294,967,295 (the maximum value of a 32-] integer), but most tag editing applications impose stricter limits.


⚫ Any field name is allowed, and there is no format that the data values must be in. This is in contrast to the ] format used for ]s, which is highly structured. Field names are also permitted to be used more than once. It is encouraged to use this feature to support multiple values, for example two <code>ARTIST=...</code> fields to list both artists of a single composition.
⚫ The data are encoded in ], and so any ] string may be used as a value.


⚫ The specification gives several example tag names such as <code>TITLE</code> and <code>TRACKNUMBER</code>. Most applications also support common ''de facto'' standards, such as <code>DISCNUMBER</code>, <code>RATING</code>, and tags for ] information. Ratings are usually mapped as 1-5 stars with 20,40,60,80,100 as the actual string values.
⚫ Any tag name is allowed, and there is no format that the data values must be in. This is in contrast to the ] format used for ]s, which is highly structured. Field names are also permitted to be used more than once. It is encouraged to use this feature to support multiple values, for example two <code>ARTIST=...</code> fields to list both artists of a single composition.


⚫ There are no provisions for storing binary data in Vorbis comments. This is by design; they are intended to be used as part of a ] such as ], and any additional binary data should be encoded into the container as a stream. The exception to this, by popular request, is a proposal to incorporate cover art into a Vorbis comment.<ref>{{cite web|title=VorbisComment, cover art|url=https://wiki.xiph.org/index.php/VorbisComment#Cover_art|website=wiki.xiph.org|publisher=]|access-date=1 October 2016}}</ref>
⚫ The specification gives several example tag names such as <code>TITLE</code> and <code>TRACKNUMBER</code>. Most applications also support common ''de facto'' standards, such as <code>DISCNUMBER</code> and tags for ] information.


⚫ ==See also==
⚫ There are no provisions for storing binary data in Vorbis comments. This is by design; they are intended to be used as part of a ] such as ], and any additional binary data should be encoded into the container as a stream. The exception to this, by popular request, is a proposal to incorporate into a Vorbis comment.
*]

⚫ *]
⚫ == See also ==
* ] *]
⚫ * ]
* ]

⚫ == References ==


⚫ ==References==
{{Reflist}} {{Reflist}}

== External links ==

*
*
*
*


{{Xiph.org}} {{Xiph.org}}
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Latest revision as of 19:38, 5 December 2024

Metadata container for Ogg file formats
Editing Vorbis comment in MusicBrainz Picard

A Vorbis comment is a metadata container used in the Ogg file format (with Vorbis, FLAC, Theora, Speex and Opus codecs). It allows information such as the title, artist, album, track number or other information about the file to be added to the file itself. However, as the official Ogg Vorbis documentation notes, “ is meant for short, text comments, not arbitrary metadata; arbitrary metadata belongs in a separate logical bitstream (usually an XML stream type) that provides greater structure and machine parseability.” Instead, the intended function of Vorbis comments is to approximate the kind of information that might be hand-inked onto a blank faced CD-R or CD-RW: a few lines of notes briefly detailing the content.

Format

A Vorbis tag is a list of fields in the format FieldName=Data. The field name can be composed of printable ASCII characters, 0x20 (space) through 0x7D (‘}’), with 0x3D (‘=’) and 0x7E (‘~’) excluded. It is case insensitive, so artist and ARTIST are the same field.

The number of fields and their length is restricted to 4,294,967,295 (the maximum value of an unsigned 32-bit integer), but most tag editing applications impose stricter limits. FLAC has a smaller limit of 24-bit in a METADATA_BLOCK_VORBIS_COMMENT, because it stores thumbnails and cover art in binary big-endian METADATA_BLOCK_PICTUREs outside of the FLAC tags.

The data is encoded in UTF-8, and so any conforming Unicode string may be used as a value.

Any field name is allowed, and there is no format that the data values must be in. This is in contrast to the ID3 format used for MP3s, which is highly structured. Field names are also permitted to be used more than once. It is encouraged to use this feature to support multiple values, for example two ARTIST=... fields to list both artists of a single composition.

The specification gives several example tag names such as TITLE and TRACKNUMBER. Most applications also support common de facto standards, such as DISCNUMBER, RATING, and tags for ReplayGain information. Ratings are usually mapped as 1-5 stars with 20,40,60,80,100 as the actual string values.

There are no provisions for storing binary data in Vorbis comments. This is by design; they are intended to be used as part of a container format such as Ogg, and any additional binary data should be encoded into the container as a stream. The exception to this, by popular request, is a proposal to incorporate cover art into a Vorbis comment.

See also

References

  1. T. Terriberry; et al. (2016). "Tag Definitions". Ogg Encapsulation for the Opus Audio Codec. IETF. sec. 5.2.1. doi:10.17487/RFC7845. RFC 7845.
  2. "Ogg Vorbis I format specification: comment field and header specification". xiph.org. Xiph.Org Foundation. 2005. Retrieved 18 February 2016.
  3. "METADATA_BLOCK_VORBIS_COMMENT". flac free lossless audio codec. Xiph.Org. 2014. Retrieved 2019-12-03.
  4. "VorbisComment, cover art". wiki.xiph.org. xiph.org. Retrieved 1 October 2016.
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