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<a name="nmm-explanation"></a>Overview</h2></div></div></div>
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<div class="titlepage"><div><div><h3 class="title">
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<p>This ontology extends NIE (Nepomuk Information Element ontology) and NFO (Nepomuk File Ontology) into the domains of multimedia, including Images, Videos, Music and Radio, and includes a couple of properties to support uPnP sharing.</p>
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<p>This ontology replaces/complements NID3 and NEXIF. Those ontologies are a direct map of the respective metadata standards, which makes very difficult to map cleanly other standards (like gstreamer metadata, mp4, ogg, and so on). Besides, those ontologies contain a lot of very low level technical information that is useless to the average user of the desktop.</p>
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<p>Our approach in NMM is to keep the minimum properties that make sense for the user, and are present in all (or almost all) specific metadata formats. A profesional photographer (or musician) who needs more fine-grained details for its documents, is free to add also nID3 information or other extensions to the ontology.</p>
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<div class="titlepage"><div><div><h3 class="title">
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<p>The core of images in NMM ontology is the class <a class="link" href="nmm-classes.html#nmm-Photo" title="nmm:Photo">nmm:Photo.</a> It is (through a long hierarchy) a <a class="link" href="nie-classes.html#nie-InformationElement" title="nie:InformationElement">nie:InformationElement</a>, an interpretation of some bytes. It has properties to store the basic information (camera, metering mode, white balance, flash), and inherits from <a class="link" href="nfo-ontology.html#nfo-Image" title="nfo:Image">nfo:Image</a> orientation (<a class="link" href="nfo-properties.html#nfo-orientation" title="nfo:orientation">nfo:orientation</a>) and resolution (<a class="link" href="nfo-properties.html#nfo-verticalResolution" title="nfo:verticalResolution">nfo:verticalResolution</a> and <a class="link" href="nfo-properties.html#nfo-horizontalResolution" title="nfo:horizontalResolution">nfo:horizontalResolution</a>).</p>
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<p>Note that for tags, nie:keywords (from nie:InformationElement) can be used, or the <a class="link" href="nao-ontology.html" title="Nepomuk Annotation Ontology (NAO): Tags, ratings and other common annotations to all classes">NAO</a> ontology.</p>