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Use Case: Video


There are several standards involved in a Video user case: CableLabs (1.1, 2.0) [1], MS TV, TV-Anytime, MPEG-7, XML-TV [2], Open IPTV, iTunes Podcast, YouTube [3], MS IMM, OMA BCAST [4] etc. The goal of this WG is to clean up this jungle and make our ontology support the briding of commonly used properties for describing video content.

The question to ask is why do you want to annotate/describe video? Presumably to:

  • Search & Retrieve: Manage local and distributed video repositories.
  • Browse: Semantic topics or personal prefs.
  • Rate & Recommend, e.g. push a video to a friend.
  • etc.

Some properties that will describe the content of these videos and enhance their sharing and reuse are;

  • Semantic descriptions (both editorial and from automatic indexing)
  • Genre descriptions
  • Information about capture/production; time/date, geo data, producer and technical information
  • Rating information
  • etc.


Perhaps the easiest use-case is a web site that allows for upload, and wants to display selected information about the media clips it gets. That use-case asks not only for metadata but also web/DOM-level APIs that give uniform access to selected metadata across a variety of file formats.

Search engines are, in some senses in scope, since we'd like search/index engines to be able to do uniform indexing of selected metadata across a variety of formats, so again we need some level of semantic match for those metadata elements across a variety of formats.

The semantic (mis)match problem is easily illustrated. Consider two metadata systems:

A has tags for Title, Artist B has tags for Title, Sub-Title, Artist, Composer

We find the same work in these two formats; A Title="Dvorak Symphony 6, II Adagio", Artist="BBC Symphony Orchestra" B Title="Symphony 6", Sub-title="II Adagio", Artist="BBC Symphony Orchestra", Composer="Dvorak, Antonin"

What does the DOM API return when the script asks for "Artist" -- does the composer get included from file B, even though in A he's been put in the title(faute de mieux)? Indeed, does the first file ever get indexed under the name of Dvorak? And so on.

We do not aim to solve the semantic mismatch problem but leave that to the application who creates the annotation / retrieval.

Other things to think about

  • is the annotation structured or simple? So, for example, is a person a structured element with family name, given name, birth date, and so on, or is it a string "Dvorak, Antonin"?
  • are annotations temporal (possibly varying in time) or atemporal?

Most metadata systems today treat it as atemporal ('what is the copyright?') but this runs into problems when e.g. media is pasted together, or for TV-like stations.

  • Not only related to the video use case: what about the data-type of annotations? Most annotation systems today use strings, but this makes life interesting when a metadata item is the cover art of an album.

This topic is related to: Services

Related Resources

[1] CableLabs Metadata


[3] YouTube


[5] TV-Anytime (Standard download area, search for ts 102 822 3-1)