| Internet-Draft | Contra Tags | April 2026 |
| Whited | Expires 12 October 2026 | [Page] |
This document defines metadata tags for describing aspects of Contra, Square, and other traditional called folk dances. These tags are meant for archivists as well as modern day callers of traditional dances.¶
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Many traditional folk dances including Contra Dance, Square Dance, English Country Dance (ECD), and others from a variety of cultural backgrounds involve a caller who leads the dance by speaking or singing the choreography in time to the music. The caller will help the dancers perform the choreography until either the music that is pre-selected for a particular dance ends or until the caller decides to stop depending on the dance style.¶
For archivists or modern callers selecting recordings of called dances there are a number of properties of the music that are not described by traditional music metadata that may be desirable to know. For example, an archivist may want to find all recordings of a specific caller playing with a specific band, but the callers name is not a commonly used metadata tag. Or a modern caller may want to filter out all tracks that have their own calls or are "crooked" (ie. don't perfectly align with the phrasing of the particular dance they are calling) to select recordings to call to when a live band is not available for a dance.¶
Having a set of standardized tags to describe such dances makes it easier for software meant for callers or archivists to display such information in a standard, searchable, way. The justification for assigned tags in Section 3.1 of [I-D.ietf-cellar-tags] also applies to this document.¶
This document only aims to cover tags specifically related to called folk dances. More general tags that may complement the tags in this document are defined in [I-D.ietf-cellar-tags].¶
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here.¶
The tags defined in the following table describe recordings that include sung or spoken dance calls.¶
Some recordings include separate tracks for the caller and the band or contain an entire evening of dances in a single file separated by a CUE track. To facilitate these use cases, these tags SHOULD set a target ([RFC9559], Section 24.2) referencing the track containing the calls.¶
| Tag Name | Type | Description |
|---|---|---|
| DANCE_FORM | UTF-8 | The form of the folk dance such as "contra" or "square". Because a large number of different folk dances exist (and because this tag may be broadly useful for dances other than called folk dances) no particular format or list of dance forms are defined. Archivists may choose to be much more particular about this tag, for example listing the specific formation of a contra dance such as "duple minor improper contra" while a caller may simply list the dance as "contra". |
| DANCE_CALLER | UTF-8 |
The name of the caller heard in the track.
This MAY be the special value
"[unknown]" (see Section 2.3).
|
| DANCE_TITLE | UTF-8 |
The name of the dance being called.
This MAY be the special value
"[unknown]" (see Section 2.3).
|
| DANCE_CHOREOGRAPHER | UTF-8 |
The name of the author of the dance being called.
This MAY be one of the special values
"[unknown]" or "[traditional]"
(see Section 2.3).
|
| DANCE_CHOREOGRAPHY | UTF-8 | The moves of the dance in plain text format. No exact style is specified. The dance author, choreographer, or other information that can be represented by other tags in this document SHOULD NOT be included and should instead be read from the appropriate tags. |
| DANCE_ROLES | UTF-8 | Role terms used in the calls. For example, "Larks/Robins" or "Leads/Follows" or "Positional" for dances that explicitly do not mention role terms for a partnership. No specific format is defined. |
| DANCE_LICENSE | UTF-8 | Like the LICENSE field defined in Section 4.13 of [I-D.ietf-cellar-tags] except relating to the choreography of the dance being called. |
The following tags are generally applicable to tracks that include the caller as well as to tracks that are uncalled but fit the form of a particular folk dance or are commonly used for folk dance. If the file contains multiple audio tracks these tags SHOULD set a target pointing to the track containing the music.¶
| Tag Name | Type | Description |
|---|---|---|
| DANCE_INTRO | UTF-8 |
The number of intro beats (not bars) before the dance starts and
before any potatoes.
For example, if a dance had a 28 beat introductory phrase
followed by 4 traditional potatoes before the first time through
the dance, this tag would be set to 28 and
DANCE_POTATOES would be set to 4.
If a tune had an 8 beat intro and no traditional potatoes this
would be set to 8 and DANCE_POTATOES would be set to 0
or unset.
|
| DANCE_POTATOES | UTF-8 | "Potatoes" are a term used to describe the synchronization beats played by the band before the tune starts to get the caller and dancers on time. This tag is the number of beats (not bars) leading up to the first time through the dance. |
| DANCE_START | UTF-8 | The start time (in milliseconds) of the first time through the dance. This is where the dancers would start moving, not where the caller would start calling. |
| DANCE_TIMES | UTF-8 | The number of complete times through the dance excluding any intro, outro, or potatoes. The exact definition will depend on the type of dance. For example, a contra dance has 64 beat (32 bar) phrases so the number of times through the dance will be the number of beats of music (excluding intros, outros, and any crooked phrasing) divided by 64. |
| DANCE_CROOKED | UTF-8 |
Whether the dance is a "crooked" tune (ie. not in perfect dance
form).
If set, this key MUST always be the value
"TRUE" or "FALSE".
|
| DANCE_IS_SONG | UTF-8 |
Whether the track is a song (has sung vocal lyrics other than
the calls) or a tune (instrumental only).
If set, this key MUST always be the value
"TRUE" or "FALSE".
|
Several tags that take free-form text may also have certain special
values such as "[unknown]" or "[traditional]" as
described above.
In software that displays this metadata these values
MAY be shown as a different, localizable, string.¶
The value "[unknown]", where permitted, indicates that the
value of the tag should be displayed but is currently unknown.
This is different from an unset tag which conveys no semantic meaning.¶
The value "[traditional]", where permitted, indicates that
the authorship of the dance is part of a folk tradition and no
particular author or authors can be assigned to it.¶
Though these tags were defined for use with Matroska files, they may
be used in other common tagging systems such as Vorbis Comments
[Vorbis] and in systems which re-use Vorbis Comments
such as FLAC
[RFC9639], Section 8.6 tags.
To use tags from this document in Vorbis Comments remove the
"DANCE_" prefix and instead use the namespace
"DANCE:".
For example, the "DANCE_POTATOES" tag becomes
"DANCE:POTATOES".¶
These tag names may be useful in other common tagging systems such as ID3 and APE where they can likely be used without modification, however, their exact use in such systems is not defined in this document.¶
This memo modifies the "Matroska Tag Names" registry defined in Section 6.1 of [I-D.ietf-cellar-tags] to add the following values:¶
| Tag Name | Tag Type | Reference |
|---|---|---|
| DANCE_FORM | UTF-8 | This document, Section 2.1 |
| DANCE_CALLER | UTF-8 | This document, Section 2.1 |
| DANCE_TITLE | UTF-8 | This document, Section 2.1 |
| DANCE_CHOREOGRAPHER | UTF-8 | This document, Section 2.1 |
| DANCE_CHOREOGRAPHY | UTF-8 | This document, Section 2.1 |
| DANCE_ROLES | UTF-8 | This document, Section 2.1 |
| DANCE_LICENSE | UTF-8 | This document, Section 2.1 |
| DANCE_INTRO | UTF-8 | This document, Section 2.2 |
| DANCE_POTATOES | UTF-8 | This document, Section 2.2 |
| DANCE_START | UTF-8 | This document, Section 2.2 |
| DANCE_TIMES | UTF-8 | This document, Section 2.2 |
| DANCE_CROOKED | UTF-8 | This document, Section 2.2 |
| DANCE_IS_SONG | UTF-8 | This document, Section 2.2 |
This document does not affect the security of the internet.¶
Thanks to Joe Harrington for his perspective as both a contra dance caller and DJ on the Shared Weight mailing list.¶