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Open Annotations schema

Example of an OAC RDF file, being used in VoV demo

 <?xml version="1.0" encoding="UTF-8"?>
 <rdf:RDF
 xmlns:cnt="http://www.w3.org/2008/content#"
 xmlns:dc="http://purl.org/dc/elements/1.1/"
 xmlns:dcterms="http://purl.org/dc/terms/"
 xmlns:dms="http://dms.stanford.edu/ns/"
 xmlns:exif="http://www.w3.org/2003/12/exif/ns#"
 xmlns:foaf="http://xmlns.com/foaf/0.1/"
 xmlns:oac="http://www.openannotation.org/ns/"
 xmlns:ore="http://www.openarchives.org/ore/terms/"
 xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
 >
 
 <rdf:Description rdf:about="urn:uuid:c437ff82-4081-4fad-a89c-1a8a3093c80f">
 <rdf:type rdf:resource="http://dms.stanford.edu/ns/TextAnnotation"/>
 <rdf:type rdf:resource="http://www.openannotation.org/ns/Annotation"/>
 <oac:hasBody rdf:resource="http://vov.indiana.edu/demo1/Line-f1r-15"/>
 <oac:hasTarget rdf:resource="http://vov.indiana.edu/demo1/Canvas-f1r#xywh=73,83,240,135&amp;t=npt:0,5"/>
 </rdf:Description>
 
 <rdf:Description rdf:about="http://vov.indiana.edu/demo1/Canvas-f1r#xywh=73,83,240,135&amp;t=npt:0,5">
 <rdf:type rdf:resource="http://dms.stanford.edu/ns/CanvasSegment"/>
 <dcterms:isPartOf rdf:resource="http://vov.indiana.edu/demo1/Canvas-f1r"/>
 </rdf:Description>
 
 <rdf:Description rdf:about="http://vov.indiana.edu/demo1/Line-f1r-15">
 <rdf:type rdf:resource="http://purl.org/dc/dcmitype/Text"/>
 <rdf:type rdf:resource="http://www.w3.org/2008/content#ContentAsText"/>
 <dc:title>Video #1</dc:title>
 <cnt:chars>Cheerios Rocket kit</cnt:chars>
 <cnt:characterEncoding>UTF-8</cnt:characterEncoding>
 </rdf:Description>
 
 <rdf:Description rdf:about="urn:uuid:c437ff82-4081-4fad-a89c-1a8a3093c80z">
 <rdf:type rdf:resource="http://dms.stanford.edu/ns/TextAnnotation"/>
 <rdf:type rdf:resource="http://www.openannotation.org/ns/Annotation"/>
 <oac:hasBody rdf:resource="http://vov.indiana.edu/demo1/Line-f1r-16"/>
 <oac:hasTarget rdf:resource="http://vov.indiana.edu/demo1/Canvas-f1r#xywh=23,53,200,145&amp;t=npt:5,25"/>
 </rdf:Description>
 
 <rdf:Description rdf:about="http://vov.indiana.edu/demo1/Canvas-f1r#xywh=23,53,200,145&amp;t=npt:5,25">
 <rdf:type rdf:resource="http://dms.stanford.edu/ns/CanvasSegment"/>
 <dcterms:isPartOf rdf:resource="http://vov.indiana.edu/demo1/Canvas-f1r"/>
 </rdf:Description>
 
 <rdf:Description rdf:about="http://vov.indiana.edu/demo1/Line-f1r-16">
 <rdf:type rdf:resource="http://purl.org/dc/dcmitype/Text"/>
 <rdf:type rdf:resource="http://www.w3.org/2008/content#ContentAsText"/>
 <dc:title>Video #2</dc:title>
 <cnt:chars>Felix and his Golden Goose</cnt:chars>
 <cnt:characterEncoding>UTF-8</cnt:characterEncoding>
 </rdf:Description>
 
 <rdf:Description rdf:nodeID="bCfJsWeh175">
 <rdf:first rdf:resource="urn:uuid:c437ff82-4081-4fad-a89c-1a8a3093c80f"/>
 <rdf:rest rdf:nodeID="bCfJsWeh185"/>
 </rdf:Description>
 
 <rdf:Description rdf:about="http://vov.indiana.edu/demo1/Canvas-f1r">
 <rdf:type rdf:resource="http://dms.stanford.edu/ns/Canvas"/>
 <dc:title>M804 f1r</dc:title>
 <exif:width rdf:datatype="http://www.w3.org/2001/XMLSchema#integer">480</exif:width>
 <exif:height rdf:datatype="http://www.w3.org/2001/XMLSchema#integer">270</exif:height>
 </rdf:Description>
 
 </rdf:RDF> 

W3C Media Fragment is being used here to specify the start/end time and the spatial area of interest (bubble note). 

 <rdf:Description rdf:about="http://vov.indiana.edu/demo1/Canvas-f1r#xywh=73,83,240,135&amp;t=npt:0,5">

Placement of the "bubbles" are relative to the video size

<exif:width rdf:datatype="http://www.w3.org/2001/XMLSchema#integer">480</exif:width>
<exif:height rdf:datatype="http://www.w3.org/2001/XMLSchema#integer">270</exif:height> 

If the video is rendered at a different size then the bubbles will have to be resized / re-placed accordingly.

With RDF annotations, it's possible to fetch annotation resource from a different location. For example: overlaying a Flickr image on top of a video.

With Constrained Targets, it's also possible to do complex annotations like a polygon or an SVG. See list of known constraints.

The OAC file is fetched via AJAX and turned into Javascript objects using a custom library. Annotations are then overlaid on top of the video using our video player.

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