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Re: more questions about the mapping table

From: Frank Nack <nack@uva.nl>
Date: Fri, 03 Apr 2009 08:51:57 +0200
Message-ID: <49D5B20D.8080407@uva.nl>
To: Tobias B├╝rger <tobias.buerger@sti2.at>
CC: Pierre-Antoine Champin <pierre-antoine.champin@liris.cnrs.fr>, Media Annotation <public-media-annotation@w3.org>
Dear all,
> Dear Pierre-Antoine,
>
> I asked the same question to me yesterday.
>
> The spec says:
>
> xmp:MetadataDate: The date and time that any metadata for this resource
> was last changed. It should be the same as or more recent than
> xmp:ModifyDate.
>
> xmpDM:metadataModDate: The date and time when the metadata was last
> modified.
>
> I actually can not spot the exact difference. So either Adobe had a
> reason why similar properties are defined in the Basic and the DM schema
> and they just did not make the difference more explicit (which I
> suppose) . Or it is redundant in the XMP Schema.
>   
This is only my assumption and it all depends on how both are used. 
Thus, my interpretation is:

xmp:MetadataDate: will be mainly used when added for the first time
xmpDM:metadataModDate: will be used for every following change.

Here is what I think about their rational behined it: Adobe first thought about the natural case that you would like to save the creation date. Later they might have realized that changing dates are different and they would like to keep them too but with a different attribute. If that is wise is a different matter.

So, if indeed both are used for different purposes we should also keep them. If it turns out that even Adobe only uses xmp:MetadataDate: we could delete the other. Has anybody a contact at Adobe to investigate the matter?

Best

	frank 


-- 
Dr. Frank Nack					
Human-Computer Studies Group (HCS)
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Received on Friday, 3 April 2009 06:52:36 GMT

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