hmedia

hMedia

hMedia ("Hypertext Media") is a simple and open format for publishing Images Video and Audio. hMedia may be embedded in HTML or XHTML, Atom, RSS, and arbitrary XML. hMedia is one of several open microformat standards.

Proposal 2008-11-11

Editor/Author

• Martin McEvoy

Contributors

In historical order of contribution

• Tantek Çelik
• Mary Hodder
• Rod Begbie
• Joshua Kinberg
• ChrisMessina
• Lisa Rein
• Manu Sporny
• Mike Johnson
• Martin McEvoy

Inspiration and Acknowledgments

Many thanks to Tantek Çelik, Mary Hodder, and Manu Sporny for their continual contributions to Media and Audio Microformats in general.

Patents

This specification is subject to a royalty free patent policy, e.g. per the W3C Patent Policy, and IETF RFC3667 & RFC3668.

Semantic XHTML Design Principles

Note: the Semantic XHTML Design Principles were written primarily within the context of developing hCard and hCalendar, thus it may be easier to understand these principles in the context of the hCard design methodology (i.e. read that first). Tantek

XHTML is built on XML, and thus XHTML based formats can be used not only for convenient display presentation, but also for general purpose data exchange. In many ways, XHTML based formats exemplify the best of both HTML and XML worlds. However, when building XHTML based formats, it helps to have a guiding set of principles.

1. Reuse the schema (names, objects, properties, values, types, hierarchies, constraints) as much as possible from pre-existing, established, well-supported standards by reference. Avoid restating constraints expressed in the source standard. Informative mentions are ok.
   1. For types with multiple components, use nested elements with class names equivalent to the names of the components.
   2. Plural components are made singular, and thus multiple nested elements are used to represent multiple text values that are comma-delimited.
2. Use the most accurately precise semantic XHTML building block for each object etc.
3. Otherwise use a generic structural element (e.g. <span> or <div>), or the appropriate contextual element (e.g. an <li> inside a <ul> or <ol>).
4. Use class names based on names from the original schema, unless the semantic XHTML building block precisely represents that part of the original schema. If names in the source schema are case-insensitive, then use an all lowercase equivalent. Components names implicit in prose (rather than explicit in the defined schema) should also use lowercase equivalents for ease of use. Spaces in component names become dash '-' characters.
5. Finally, if the format of the data according to the original schema is too long and/or not human-friendly, use <abbr> instead of a generic structural element, and place the literal data into the 'title' attribute (where abbr expansions go), and the more brief and human readable equivalent into the element itself. Further informative explanation of this use of <abbr>: Human vs. ISO8601 dates problem solved

Scope

Images, Video and Audio regularly share several common fields. hMedia has been based on a minimal common subset based on the analysis of 225 media related web pages. All fields discovered during analysis occur more than 80% of the time or more across each of the target domains listed on the Media Info Examples page. hMedia was developed using the Microformats Process and Design Principles.

Introduction

Mary Hodder - 22 Jan 2006

There are many ways to publish media by users, but as people try to access those remixing and aggregation become more and more prevalent, having consistent records becomes important. Audio, photos and video show up in each other's publishing spaces, even though they are unique media objects. A photo might be next to the link for an audio piece, as it's visual artwork. A video can be comprised of quotes of other videos, photos and audio. Still photos can be made from videos. All three types of objects can contain subsets of media that is tagged and described.

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119.

Format

Abstract

hMedia is a single media publishing format that relates to Images, Video and Audio in a meaningful, organized and structured way. Wherever possible field names have been chosen from those defined by the hCard standard.

Schema

• hMedia hmedia
  • fn REQUIRED. Text.
  • contributor. OPTIONAL. using text or hcard.
  • photo[1]. Using the HTML IMG element.
  • video[1]. Using the HTML elemens DIV, SPAN or OBJECT.
  • enclosure[1]. A URI using the rel-design-pattern.
  • item OPTIONAL. Using multiple properties from hmedia.

[1] hMedia MUST contain at least one.

Schema Definition

hmedia

hMedia is used to describe semantic information associated with Images, Videos and Audio.

fn

The name of a media. Reused from hcard

• The element is identified by the class name fn.
• hMedia MUST have at least fn.

contributor

A Contributor is any person or organization that takes part in the creation or distribution of the Media. Reused from haudio

• The element is identified by the class name contributor.
• hMedia MAY include one or more contributors.
• The contents of the element SHOULD include a valid hCard.

photo

An embedded Image or Photograph of the Media. Reused from hcard

• The element is identified by the class name photo.
• hMedia MAY include one or more photo's.
• The element SHOULD use an <img> element.
• The <img> element attributes height and width MAY be used to determine the dimensions of a photo

video

The contents are an embedded video or movie of the Media such as a Flash Movie.

• The element is identified by the class name video.
• hMedia MAY include one or more video's.
• The element SHOULD use a <div>, <span> or <object> element.

enclosure

Indicates that the referred url is a download of the Media. Using rel-enclosure.

• The element is identified by a URI using the rel-design-pattern, the rel attribute SHOULD contain the value of enclosure.
• hMedia MAY include one or more enclosure's.
• The type of the file SHOULD be specified by using the type specifier for a URI.

item

A container element for another Media item. Reused from haudio

• The element is identified by the class name item.
• hMedia MAY have one or more items.
• item MUST be processed opaquely.
• The contents of item MUST be marked up using properties in hMedia.

XMDP Profile

<dl class="profile">
 <dt>class</dt>
 <dd><p>
  <a rel="help" href="http://www.w3.org/TR/html401/struct/global.html#adef-class">
   HTML4 definition of the 'class' attribute.</a>
  This meta data profile defines some 'class' attribute values (class names) 
  and their meanings as suggested by a 
  <a href="http://www.w3.org/TR/WD-htmllink-970328#profile">
   draft of "Hypertext Links in HTML"</a>.</p>
  <dl>
   <dt>hmedia</dt>
   <dd>
    Used to describe semantic information associated with Images, Videos and Audio.
   </dd>
   <dt>fn</dt>
   <dd>
    The name of a media
   </dd>
   <dt>contributor</dt>
   <dd>
    A Contributor is any person or organization that takes part in the creation or distribution of the Media
   </dd>
   <dt>photo</dt>
   <dd>
    An embedded Image or Photograph of the Media.
   </dd>
   <dt>video</dt>
   <dd>
    An embedded video or movie of the Media.
   </dd>
   <dt>enclosure</dt>
   <dd>
     Indicates that the referred url is a download of the Media.
   </dd>
   <dt>item</dt>
   <dd>
    A container element for another Media item.
   </dd>
  </dl>
 </dd>
</dl>

Modularity

Although media items are sometimes presented on their own they are often found in data structures that are supported by existing microformats. It should therefore be possible to use the media microformat as a child (or in some cases a parent) of these microformats.

Distribution and Syndication

• hAtom

Podcast feeds reference a sequence of media items. A media microformat could therefore be used as a child element of hAtom.

Media Events

• hCalendar

hMedia may used to describe a continuous media stream e.g. a TV channel. An event or a schedule of events on the channel can be signaled using vevent as child elements. This combination would provide what is necessary to capture a specific event; the media stream information and the timing information.

Media Comments

• Comment

Comments and Feedback on media items often come up in popular publishing practice, a comment microformat could be used when marking up Media Comments

References

Normative References

• hcard
• rel-design-pattern
• datetime-design-pattern
• rel-enclosure
• rel-tag

Informative References

• HTML4 Image element
• HTML4 Object element
• HTML4 rel Definition

Similar Work

• Media Chapters
• hAudio
• Video Info
• Photo Notes

Work in progress

Brainstorming

See: media-info-brainstorming

Discussions

• Please forward questions and ideas to the Microformats New mailing list.

Issues

See: media-info-issues

Related pages

• media-info-examples
• media-info-formats
• media-info-brainstorming