Ogg Vorbis (and FLAC) Comment Field Recommendations

Note: The following information was originally published at http://reactor-core.org/ogg-tagging.html, but this page is no longer available. I found this information to be extremely useful, so I'm posting a copy of it here for archival purposes. This copy was pulled from a mirror of the original site, located at http://age.hobba.nl/audio/mirroredpages/ogg-tagging.html, on 05/09/2009.

This is currently a direct copy of the original source content, modified only slightly in order to match the format of my site. In time I may modify or extend it, but any changes will be clearly indicated.

Updated 12/14/2010:  Additional proposed fields added below, indicated by "proposed by Legroom.net."

Suggestions For Tagging Vorbis/FLAC Files

Originally published Thu Jul 3 20:35:53 PDT 2003

The following recommendations were developed by a community of Ogg/Vorbis users for their own use.

The purpose of the set of tags in this recommendation is to provide information about the track that contains the tags. It is not the purpose of the tags to provide general information about the piece of music in the track, such as a listing of every recording that contains that same piece of music. External databases and the internal Ogg metadata stream are appropriate for information about the music, except where it fills one of the 4 goals listed below.

Goals

  1. Identify a track so the listener can know what he is listening to.
  2. Identify a track to allow music companies to profit from it.
  3. Meet goals 1 and 2 without access to external data sources.
  4. Identify a track within a database that contains information about the track.

NOT goals

  1. Stuff every available bit of information about a track and the CD it is on into the TAGS section. (liner notes, lyrics, the bandleaders dogs name...)
  2. Backward compatibility with ID3 and MP3 tagging schemes, structures, and infrastructures.

Piracy happens. We can't prevent it. At least we can encourage less damaging behaviors, such as making sure than when someone likes a track, they have enough information to reimburse the artist by going out and purchasing the original source media the music came on.

These recommendations are written in the context of http://www.xiph.org/ogg/vorbis/doc/v-comment.html, which is authoritative.

All tags are OPTIONAL; you can have an ogg file with NO tags present and it will still be compliant. It is RECOMMENDED that you put enough tags in the ogg to meet goals 1 through 4 above. The tags needed will vary with each recording, and will often be no more than the tags already used.

Before we continue, here is a nifty bourne shell function you can stick in your ~/.bash_profile:

ogg-grep () {
   REGEX="$1";
   shift;
   for i in "$@"; do
      vorbiscomment -l "$i"|grep -i "$REGEX" >/dev/null && echo "$i";
   done;
}

You could use it like this:

ogg-grep "CONDUCTOR=.*Karajan" ~/music/oggfiles/*.ogg

It would display, one per line, all the ogg files where Karajan was the conductor of the piece.

What is the effect of following these Recommendations?

USERS
Users will be playing their oggs; their player software is expected to display the tags that exist in an oggfile, intelligently.
Therefore the users are not affected by these recommendations and need know nothing about them. Player programs ARE affected, and their job should be made as easy as possible.
ENCODERS
There will be a subset of users who create ogg files. Inasmuch as it is their responsibility to tag their files correctly, it would be nice if they knew about these recommendations. However, their ripping software should make it trivial for them to fill in the correct tags in the common cases, and let them access the full tagset if they feel they need it.
Therefore, encoders will almost not notice the adoption of these recommendations, unless they wanted to benefit from its increased flexibility, in which case they will rejoice. Ripper and tagging SOFTWARE on the other hand will need to support these recommendations, and again, its job should be made as easy as possible.
CODERS
Coders are those who write the software used by users and encoders. They are the ones who will need to make their software compliant, and the ones who need to make sure their software is easy for people to use.
Therefore, it is the coders who will be affected most by these recommendations. Their job should be made as easy as possible so they can support it trivially and well.

Compliance

A compliant Ogg player program will intelligently display, or let the user specify how to display, all the tags in an Ogg file.

A compliant Ogg file may contain tags not in these recommendations.

Compliant tag editors and rippers may support tags not in these recommendations, but should encourage use of recommended tags over tags not in this document.

Character Set Encoding of Tags

UTF-8 is the default encoding for tag data. Unfortunately UTF-8 muffed it for Asian languages by doing the equivalent of giving the same character codes to English, Russian, and Greek letters.

Fortunately UTF-8 itself has an internal, standard solution to the problem: http://www.unicode.org/unicode/reports/tr27/#tag which basically says: mark the language of text with U+E0001 LANGUAGE TAG, followed by the RFC 3066 language ID (ie. "ja") encoded in lowercase ASCII plus 0xE0000. This is the only mechanism recognized by this document.

Programs which don't want to interpret such markup can simply ignore it; it is zero width. The scope of the language setting is until the end of the tag, or until a new language setting is encountered, whichever comes first.

We have the following STANDARD tags

Singleton tags, which should only appear once. If one of these tags appears more than once, its last appearance should be displayed if there is only room to display one instance of the tag.

ALBUM
if appropriate, an album name
ARTIST
for information to be displayed on systems with limited display capabilities. it is not a replacement for the ENSEMBLE and PERFORMER tags, but typically will summarize them.
PUBLISHER
who publishes the disc the track came from
COPYRIGHT
who holds copyright to the track or disc the track is on
DISCNUMBER
if part of a multi-disc album, put the disc number here
ISRC
this number lets you order a CD over the phone from a record shop.
EAN/UPN
there may be a barcode on the CD; it is most likely an EAN or UPN (Universal Product Number).
LABEL
the record label or imprint on the disc
LABELNO
record labels often put the catalog number of the source media somewhere on the packaging. use this tag to record it.
LICENSE
the license, or URL for the license the track is under. for instance, the Open Audio license.
OPUS
the number of the work; eg, Opus 10, BWV 81, K6
SOURCEMEDIA
the recording media the track came from. eg, CD, Cassette, Radio Broadcast, LP, CD Single
TITLE
"the work", whether a symphony, or a pop song
TRACKNUMBER
the track number on the CD
VERSION
Make sure you don't put DATE or LOCATION information in this tag. "live", "acoustic", "Radio Edit" "12 inch remix" might be typical values of this tag
ENCODED-BY
The person who encoded the Ogg file. May include contact information such as email address and phone number.
ENCODING
Put the settings you used to encode the Ogg file here. This tag is NOT expected to be stored or returned by cddb type databases. It includes information about the quality setting, bit rate, and bitrate management settings used to encode the Ogg. It also is used for information about which encoding software was used to do the encoding.

Additional singletons proposed by Legroom.net.

LYRICS
full lyrics for the track
WEBSITE
a full URL linking to the album's official web site

The remaining tags are multiples; if they are present more than once, all their occurrences are considered significant.

COMPOSER
composer of the work. eg, Gustav Mahler
ARRANGER
the person who arranged the piece, eg, Ravel
LYRICIST
the person who wrote the lyrics, eg Donizetti
AUTHOR
for text that is spoken, or was originally meant to be spoken, the author, eg JRR Tolkien
CONDUCTOR
conductor of the work; eg Herbert von Karajan. choir directors would also use this tag.
PERFORMER
individual performers singled out for mention; eg, Yoyo Ma (violinist)
ENSEMBLE
the group playing the piece, whether orchestra, singing duo, or rock and roll band.
PART
a division within a work; eg, a movement of a symphony. Some tracks contain several parts. Use a single PART tag for each part contained in a track. ie, PART="Oh sole mio"
PARTNUMBER
The part number goes in here. You can use any format you like, such as Roman numerals, regular numbers, or whatever. The numbers should be entered in such a way that an alphabetical sort on this tag will correctly show the proper ordering of all the oggs that contain the contain the piece of music.
GENRE
like the genre tag from the cddb but without the limitations. You can put any genre you want in this tag. If you think "Pink Floyd" are a genre unto themselves, say so here. For crossover works, or ambiguous works, use as many GENRE tags as you think it takes to describe the styles used.
DATE
date or date-time of relevance to the track. The date must be in ISO 8601 format, but may be followed by a space character, then any text you wish, including the same date in any other format. None of the alternate formats in ISO 8601 may be used. Only the primary format in ISO 8601 is to be used. q.v. http://www.cl.cam.ac.uk/~mgk25/iso-time.html eg, DATE="1999-08-16 (recorded)" or DATE="1999-08-16 recorded August 16, 1999"
LOCATION
location of recording, or other location of interest
COMMENT
additional comments of any nature.

Examples of Tag Usage

Here is a typical example for most POP music.

ALBUM=Joyride
ENSEMBLE=Roxette
TITLE=Joyride

Here is what you might see if you played it with ogg123:

Album: Joyride
Ensemble: Roxette
Title: Joyride

Bitstream is 2 channel, 44100Hz

Here is a typical example for CLASSICAL music.

LABEL=Deutsche Grammophon
COMPOSER=Gustav Mahler
CONDUCTOR=Herbert von Karajan
ENSEMBLE=Berliner Philharmoniker
PERFORMER=Liza don Getti (soprano)
PERFORMER=Joe Barr (piano)
OPUS=8
PART="movement 1. Allegreto"
TITLE="Symphony no. 4"
COMMENT=I was present when this recording was made; met my wife there.
COMMENT=The flautist ate a green pickle with a purple egg.

And here is what you might see if you played it with ogg123:

Playing from file ogg/mystery_file_I_got_from_gnutella.ogg
Label: Deutsche Grammophon
Composer: Gustav Mahler
Conductor: Herbert von Karajan
Ensemble: Berliner Philharmoniker
Performers: Liza don Getti (soprano)
            Joe Barr (piano)
Title: Symphony no. 4 (Opus 8), movement 1. Allegreto
Comments: I was present when this recording was made; met
          my wife there. The flautist ate a green pickle
          with a purple egg.

Bitstream is 2 channel, 44100Hz

Here is a really whacked example that uses all the tags in this document.

OPUS=1
COMPOSER=Stravinsky
ARRANGER=Ravel
PRODUCER=Fat Fred
LYRICIST=Puccini
AUTHOR=Reverend Lovejoy
CONDUCTOR=Zubin Meta
PERFORMER=Nix Nax (piccolo)
ENSEMBLE=Upper East German Woodwind Band
LABEL=BIZ
LABELNO=54001
ISRC=132938420384
EAN/UPN=11111111111
TRACKNUMBER=8
ALBUM=Tootles and Tunes
TITLE=The Life and Times of Friar Tux
PART=1. Minuet (allegro con molto)
GENRE=classical (avant garde)
DATE=1974-09-03 recorded
LOCATION=Easthampton Cathedral, Chesterwickshire
COPYRIGHT=Unclaimed
COMMENT=This is the wierdest, ugliest piece of music I've ever heard. Its the ugly duckling of the classical music world.

And here is what it would like like from ogg123

Album: Tootles and Tunes
Track: 8
Title: The Life and Times of Friar Tux (Opus 1), first minuet (allegro con molto)
Composer: Stravinksy
Conductor: Zubin Meta
Performer: Nix Nax (piccolo)
Ensemble: Upper East German Woodwind Band
Arranger: Ravel
Lyricist: Puccini
Author: Reverend Lovejoy
Label: BIZ
Copyright: Unclaimed
EAN/UPN: 111111111
Genre: classical (avant garde)
Producer: Fat Fred
Recorded on: Sept 3, 1974
Recorded at: Easthampton Cathedral, Chesterwickshire
Comments: This is the wierdest, ugliest piece of music I've ever heard.
          Its the ugly duckling of the classical music world. It has a
          monotone reading throughout, of that famous sermon by
          Reverend Lovejoy, "Life and Times of Friar Tux"

Bitstream is 2 channel, 44100Hz

This document is provided for reference purposes only. It is not endorsed by Reactor Core staff or Jonathan Walther, unless otherwise stated. The battle for Christ's Kingdom is always changing, moving to new fronts. The Christian soldier must be trained to prove every thought, ideology, train of reasoning, and claim to truth he meets. Slander is from Satan; Truth is from the Holy Spirit. The wise and the just check every fact for themselves before judging. (1 Thessalonians 5:21, 1 John 4:1-3, John 14:26, John 16:26, Revelation 12:10, Proverbs 14:15, Proverbs 18:13)