Internet Engineering Task Force ssw. Whited, Ed. Internet-Draft Independent Intended status: Informational 9 April 2026 Expires: 11 October 2026 Metadata for Called Folk Dances draft-swhited-contra-tags-00 Abstract This document defines Matroska 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. Status of This Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at https://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." This Internet-Draft will expire on 11 October 2026. Copyright Notice Copyright (c) 2026 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/ license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Whited Expires 11 October 2026 [Page 1] Internet-Draft Contra Tags April 2026 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3 2. Assigned Tags . . . . . . . . . . . . . . . . . . . . . . . . 3 2.1. Called Tracks . . . . . . . . . . . . . . . . . . . . . . 3 2.2. Called or Uncalled Tracks . . . . . . . . . . . . . . . . 4 2.3. Special Values . . . . . . . . . . . . . . . . . . . . . 6 3. Use with Vorbis Comments . . . . . . . . . . . . . . . . . . 6 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6 5. Security Considerations . . . . . . . . . . . . . . . . . . . 7 6. Normative References . . . . . . . . . . . . . . . . . . . . 7 7. Informative References . . . . . . . . . . . . . . . . . . . 7 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 8 1. Introduction 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 (in the case of ECD) or until the caller decides to stop (contra, square). 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 is of use for archivists preserving field recordings, and for modern day callers of folk dances such as Modern Urban Contra callers who can use such tags to more rapidly select music that is suitable for calling when working with recorded music. Whited Expires 11 October 2026 [Page 2] Internet-Draft Contra Tags April 2026 1.1. Requirements Language 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. 2. Assigned Tags 2.1. Called Tracks The tags defined in the following table describe recordings that incude sung or spoken dance calls. If the recording includes a separate track for the caller or otherwise includes multiple audio tracks (ie. an entire evening of dances in a single file separated with a CUE track) these tags SHOULD set a target pointing to the exact 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]". | +---------------------+-------+-------------------------------------+ | DANCE_TITLE | UTF-8 | The name of the dance being | | | | called. This may be the special | | | | value "[unknown]". | +---------------------+-------+-------------------------------------+ | DANCE_CHOREOGRAPHER | UTF-8 | The name of the author of the | | | | dance being called. This may be | Whited Expires 11 October 2026 [Page 3] Internet-Draft Contra Tags April 2026 | | | one of the special values | | | | "[unknown]" or "[traditional]". | +---------------------+-------+-------------------------------------+ | DANCE_CHOREOGRAPHY | UTF-8 | The moves of the dance in plain | | | | text format. No exact style is | | | | specified. The dance author, | | | | choreographer, difficulty, or any | | | | callers notes SHOULD NOT be | | | | included and should instead be | | | | read from the appropriate tags. | +---------------------+-------+-------------------------------------+ | DANCE_CALLER_NOTES | UTF-8 | Any notes provided by the | | | | choreographer or the caller | | | | related to calling the dance. | | | | For example, many choreographers | | | | will provide notes such as "When | | | | teaching the A1 part, have the | | | | Larks cross over first...". Or | | | | individual callers may provide | | | | notes on their calling card such | | | | as "Beginner friendly" or | | | | "Advanced dance". | +---------------------+-------+-------------------------------------+ | 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. | +---------------------+-------+-------------------------------------+ Table 1: Tags 2.2. Called or Uncalled Tracks 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. Whited Expires 11 October 2026 [Page 4] Internet-Draft Contra Tags April 2026 +====================+=======+======================================+ | Tag Name | Type | Description | +====================+=======+======================================+ | DANCE_HAS_POTATOES | UTF-8 | "Potatoes" are a term used to | | | | describe the syncronization beats | | | | played by the band before the | | | | tune starts to get the caller and | | | | dancers on time. If set, this | | | | key MUST always be the value | | | | "TRUE" or "FALSE". | +--------------------+-------+--------------------------------------+ | DANCE_POTATOES | UTF-8 | The number of beats (not bars), | | | | regardless of whether they are | | | | traditional potatoes or an | | | | introductory phrase, of music | | | | before the first time through the | | | | dance. If the DANCE_HAS_POTATOES | | | | tag is "FALSE" this represents | | | | beats in an introductory phrase, | | | | otherwise it represents the | | | | number of traditional potatoes | | | | (normally 4). If the BPM | | | | ([I-D.ietf-cellar-tags], | | | | Section 4.10) and DANCE_START | | | | tags are set, this should be | | | | approximately DANCE_START / 3600 | | | | * BPM rounded to the nearest | | | | natural number. | +--------------------+-------+--------------------------------------+ | 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. If | | | | the BPM ([I-D.ietf-cellar-tags], | | | | Section 4.10) and DANCE_POTATOES | | | | tags are set, this should be | | | | approximately DANCE_POTATOES / | | | | BPM * 3600. | +--------------------+-------+--------------------------------------+ | 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 tpye of dance. For example, | | | | a contra dance has 64 beat (32 | | | | bar) phrases so the number of | | | | times through the dance will be | Whited Expires 11 October 2026 [Page 5] Internet-Draft Contra Tags April 2026 | | | 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". | +--------------------+-------+--------------------------------------+ Table 2: Tags 2.3. Special Values Several tags that take freeform text may also have certain special values such as "[unknown]" or "[traditional]" as described above. These values MAY be shown as a different string, possibly translated into the users native language. 3. Use with Vorbis Comments 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". 4. IANA Considerations This memo modifies the "Matroska Tag Names" registry defined in Section 6.1 of [I-D.ietf-cellar-tags] to add the following values: Whited Expires 11 October 2026 [Page 6] Internet-Draft Contra Tags April 2026 +=====================+==========+============================+ | 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_CALLER_NOTES | 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_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 | +---------------------+----------+----------------------------+ Table 3: Additions to the "Matroska Tag Names" Registry 5. Security Considerations This document does not affect the security of the internet. 6. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, . 7. Informative References Whited Expires 11 October 2026 [Page 7] Internet-Draft Contra Tags April 2026 [RFC9639] van Beurden, M.Q.C. and A. Weaver, "Free Lossless Audio Codec (FLAC)", RFC 9639, DOI 10.17487/RFC9639, December 2024, . [I-D.ietf-cellar-tags] Lhomme, S., Bunkus, M., and D. Rice, "Matroska Media Container Tag Specifications", Work in Progress, Internet- Draft, draft-ietf-cellar-tags-23, 26 February 2026, . [Vorbis] Xiph.Org, "Ogg Vorbis I format specification: comment field and header specification", . Author's Address Sam Whited (editor) Independent Email: sam@samwhited.com URI: https://blog.samwhited.com Whited Expires 11 October 2026 [Page 8]