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Re: YouTube mapping table

From: Sebastian Schaffert <sebastian.schaffert@salzburgresearch.at>
Date: Tue, 31 Jan 2012 14:24:53 +0100
Cc: public-media-annotation@w3.org
Message-Id: <724653E3-E8B6-4404-BF94-AC4C568A9BCB@salzburgresearch.at>
To: Florian Stegmaier <stegmai@dimis.fim.uni-passau.de>
Dear all,

while implementing a YouTube-Media Ontology mapper, I encountered the following additional problems:

1. ATOM Protocol

YouTube nowadays uses the ATOM protocol as default, not RSS (still available as secondary protocol though)


2. Keywords (ma-ont:keyword)

XPath: /atom:entry/media:group/media:keywords

YouTube will return a single value with a comma-separated list of keywords; in Media Ontology, this should be split into at least the individual keywords. 

An alternative offered by the YouTube Atom API would be /atom:entry/atom:category[@scheme='http://gdata.youtube.com/schemas/2007/keywords.cat']/@term

3. Category (ma-ont:genre)

XPath: /atom:entry/media:group/media:category

YouTube returns the category as a string, but the reference defines that this string should be mapped to the YouTube Schema URI, i.e. 

if /atom:entry/media:group/media:category = Music, then the mapping should be to http://gdata.youtube.com/schemas/2007#Music; 

reference: http://code.google.com/intl/de-DE/apis/youtube/2.0/reference.html#youtube_data_api_tag_category


4. Copyright (ma-ont:copyright)

XPath: /atom:entry/media:group/media:license

the YouTube API returns copyright information as media:license element. This could be mapped to the ma-ont:copyright property with a bit of transformation, because YouTube only offers two values, "cc" for creative commons and "youtube" for their own license.

reference: http://code.google.com/intl/de-DE/apis/youtube/2.0/reference.html#youtube_data_api_tag_media:license



Here is my complete mapping implementation:
    private static Map<String,ValueMapper> mediaOntMappings = new HashMap<String, ValueMapper>();
    static {
        mediaOntMappings.put("http://www.w3.org/ns/ma-ont#identifier", new XPathLiteralMapper("/atom:entry/atom:id"));
        mediaOntMappings.put("http://www.w3.org/ns/ma-ont#title",      new XPathLiteralMapper("/atom:entry/atom:title"));
        mediaOntMappings.put("http://www.w3.org/ns/ma-ont#locator",    new XPathURIMapper("/atom:entry/media:group/media:content/@url")); // URI
        mediaOntMappings.put("http://www.w3.org/ns/ma-ont#creator",    new XPathURIMapper("/atom:entry/atom:author/@uri"));               // URI
        mediaOntMappings.put("http://www.w3.org/ns/ma-ont#date",       new XPathLiteralMapper("/atom:entry/atom:published","dateTime"));
        mediaOntMappings.put("http://www.w3.org/ns/ma-ont#location",   new XPathLiteralMapper("/atom:entry/georss:where/gml:Point/gml:pos"));
        mediaOntMappings.put("http://www.w3.org/ns/ma-ont#description",new XPathLiteralMapper("/atom:entry/media:group/media:description"));
        mediaOntMappings.put("http://www.w3.org/ns/ma-ont#keyword",    new XPathLiteralMapper("/atom:entry/atom:category[@scheme='http://gdata.youtube.com/schemas/2007/keywords.cat']/@term"));
        mediaOntMappings.put("http://www.w3.org/ns/ma-ont#genre",      new YoutubeCategoryMapper("/atom:entry/media:group/media:category"));       // URI, should  be mapped to YouTube schemas (http://gdata.youtube.com/schemas/2007#)
        mediaOntMappings.put("http://www.w3.org/ns/ma-ont#rating",     new XPathLiteralMapper("/atom:entry/gd:rating/@average","float"));          // Float
        mediaOntMappings.put("http://www.w3.org/ns/ma-ont#copyright",  new XPathURIMapper("/atom:entry/media:group/media:license/@href"));         // URI of license terms
        mediaOntMappings.put("http://www.w3.org/ns/ma-ont#publisher",  new XPathURIMapper("/atom:entry/atom:author/@uri"));               // URI
        mediaOntMappings.put("http://www.w3.org/ns/ma-ont#compression",new XPathLiteralMapper("/atom:entry/media:group/media:content/@type"));
        mediaOntMappings.put("http://www.w3.org/ns/ma-ont#duration",   new XPathLiteralMapper("/atom:entry/media:group/media:content/@duration","integer"));
        mediaOntMappings.put("http://www.w3.org/ns/ma-ont#format",     new XPathLiteralMapper("/atom:entry/media:group/media:content/@type"));
        mediaOntMappings.put("http://xmlns.com/foaf/0.1/thumbnail",    new XPathURIMapper("/atom:entry/media:group/media:thumbnail/@url"));
        mediaOntMappings.put("http://rdfs.org/sioc/ns#num_views",      new XPathLiteralMapper("/atom:entry/yt:statistics/@viewCount","integer"));
    }

I will publish the source code as part of our Linked Media Framework as soon as our servers are running again :)



Am 31.01.2012 um 12:55 schrieb Florian Stegmaier:

> Dear Thierry, all,
> 
> our colleagues at Salzburg Research are using our ontology (and soon the API) in their Linked Media Framework. I have put Sebastian into CC. He has just send me the pointer, that there is a mapping for ma:creator. In our mapping table there is N/A.
> 
> Please refer to [1] and mapping would be as follows:
> 
> "/atom:entry/atom:author/@uri" -> "http://www.w3.org/ns/ma-ont#creator"
> 
> We should discuss this in todays telecon. He will finalize his work on YouTube today and will provide me his mappings as well.
> 
> Cheers.
> 
> [1] http://gdata.youtube.com/feeds/api/videos/EM4vblG6BVQ
> _____________________________
> Dipl. Inf. Florian Stegmaier
> Chair of Distributed Information Systems
> University of Passau
> Innstr. 43
> 94032 Passau
> 
> Room 248 ITZ
> 
> Tel.: +49 851 509 3063
> Fax: +49 851 509 3062
> 
> stegmai@dimis.fim.uni-passau.de
> https://www.dimis.fim.uni-passau.de/iris/
> http://twitter.com/fstegmai
> _____________________________
> 
> 
> 
> _____________________________
> Dipl. Inf. Florian Stegmaier
> Chair of Distributed Information Systems
> University of Passau
> Innstr. 43
> 94032 Passau
> 
> Room 248 ITZ
> 
> Tel.: +49 851 509 3063
> Fax: +49 851 509 3062
> 
> stegmai@dimis.fim.uni-passau.de
> https://www.dimis.fim.uni-passau.de/iris/
> http://twitter.com/fstegmai
> _____________________________
> 

Sebastian
-- 
| Dr. Sebastian Schaffert          sebastian.schaffert@salzburgresearch.at
| Salzburg Research Forschungsgesellschaft  http://www.salzburgresearch.at
| Head of Knowledge and Media Technologies Group          +43 662 2288 423
| Jakob-Haringer Strasse 5/II
| A-5020 Salzburg
Received on Tuesday, 31 January 2012 13:25:31 GMT

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