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Re: Publishing the Mapping Table (was minutes of 2009-03-10 teleconference)

From: David Singer <singer@apple.com>
Date: Wed, 18 Mar 2009 17:44:43 -0700
Message-Id: <p0624085ac5e7448152bd@[]>
To: Veronique Malaise <vmalaise@few.vu.nl>, Felix Sasaki <felix.sasaki@fh-potsdam.de>
Cc: RaphaŽl Troncy <Raphael.Troncy@cwi.nl>, "public-media-annotation@w3.org" <public-media-annotation@w3.org>
At 17:59  +0100 18/03/09, Veronique Malaise wrote:
>Hi Felix, all,
>I think that the first case that David was 
>mentioning is typically answered by a "central 
>authoritative" ontology or equivalence 
>repository: for one query, it gives the possible 
>properties in different vocabularies (XMP, MPEG7 
>etc); the second case is the skos modeling case 
>*without* a "central authoritative" ontology or 
>equivalence repository, which states that one 
>property in one vocabulary is comparable (in 
>some way) to a property in another vocabulary. 
>But I might have misunderstood teh point...

Perhaps!  We are both being rather brief, so let me explain more.

QuickTime can convert files between different 
formats.  When we do that, there is a question of 
what we do with the meta-data.  Generally, we 
don't convert it, because conversion really needs 
a perfect bi-directional relationship:  if you 
were to convert and convert back, you'd still get 
something valid and true.  In many cases, the two 
tags are not perfect synonyms (for example, the 
discussion about creation tools and creation 
agents), and so it's not a reversible (two-way) 

We *also* have a system (spotlight) of indexing 
files on Mac OS X.  For this system we want to 
build a database from the meta-data, that is 
independent of the file format.  We want to 
answer questions like "who was the author", "when 
was it written", "what is the title", and so on. 
For this purpose, we only need a one-way mapping, 
and it doesn't need to be an exact match.  If 
Spotlight is willing to accept more in (say) a 
'created by' field than the file format is able 
to express, it doesn't matter.

The second paragraph is dealing with "If X is 
your question, and Y is your file format, you can 
get an answer by doing Z".  It is way easier to 
answer than "If Q is your source format, and R is 
the meta-data item, and S is your destination 
format, then you can convert by doing actions T".

Am I making better sense now?

If we want to support uniform indexing and 
display of meta-data in media files, via DOM APis 
or recommended indexing practices, we probably 
only need the first of these, for a reasonable 
and small set of tags.  This is achievable...

>On Mar 18, 2009, at 5:34 PM, Felix Sasaki wrote:
>>Hello Raphael,
>>I missed that one, sorry. I think the reason is 
>>that David was asking whether we want to 
>>provide the functionality of a two way mapping, 
>>and not specifically referring to the 
>>expressive power of SKOS or another possible 
>>formalization which may be used to implement 
>>the functionality. If I understand you right 
>>you just explained the SKOS example, but did 
>>not ask for the functionality?
>>2009/3/18 RaphaŽl Troncy 
>>Dear Felix,
>>everything we have done so far, including the 
>>mapping table, the toy implementations of the 
>>API and the formalization example in SKOS etc., 
>>are one way mapping, mostly using properties 
>>available in XMP as the target of the mapping. 
>>That is, property A-1 from format A can be 
>>mapped to property XMP-x. So far I have not 
>>seen anybody in the Working Group asking for a 
>>two way mapping, so I regard this as an 
>>unspoken consensus that we are working "only" 
>>on the one way mapping.
>>This is *not* exactly true.
>>In the case of the toy example of a possible 
>>mapping formalization in SKOS, we have a 
>>two-ways mapping, since for example, the 
>>skos:related property is owl:symmetric [1]. The 
>>skos:mappingRelation might be reflexive, 
>>symmetric too.
>>  RaphaŽl
>>[1] <http://www.w3.org/TR/skos-primer/>http://www.w3.org/TR/skos-primer/
>>RaphaŽl Troncy
>>CWI (Centre for Mathematics and Computer Science),
>>Science Park 123, 1098 XG Amsterdam, The Netherlands
>>Tel: +31 (0)20 - 592 4093
>>Fax: +31 (0)20 - 592 4312
>>Web: <http://www.cwi.nl/%7Etroncy/>http://www.cwi.nl/~troncy/

David Singer
Multimedia Standards, Apple Inc.
Received on Thursday, 19 March 2009 00:45:41 UTC

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