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cc-metadata - Re: Fwd: Multiple encodings & ccvalidator

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Subject: discussion of the Creative Commons Metadata work

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  • From: Mike Linksvayer <ml AT creativecommons.org>
  • To: discussion of the Creative Commons Metadata work <cc-metadata AT lists.ibiblio.org>
  • Subject: Re: Fwd: Multiple encodings & ccvalidator
  • Date: Mon, 04 Oct 2004 09:27:11 -0700

Sylvain ZIMMER wrote:
The problem is that I have multiple encodings of my files (MP3, OGG q4,
OGG q7, ...) , so what about the <Work> tag ? The urn:sha1 will differ in
the different encodings...

If I got it, if I only put the SHA1 of my MP3 files, the CCTAG validation
will fail on the OGG files, right ?

Right.

So is having multiple <Work> tags for a track the only solution ?

Yes, but...

That
wouldn't be great at all... what if we want to encode on the fly (like
allofmp3.com), and we have tons of sha1's for only one track ?

...Another option could be to repeat dc:identifier properties for however many distinct files you have. I suspect I've mentioned this possibility in the past but haven't added the possibility to <http://creativecommons.org/technology/nonweb>.

Example:

<Work about="http://example.com/mysong.wav";>
<license rdf:resource="http://creativecommons.org/licenses/by/2.0/"/>
<dc:identifier rdf:resource="urn:sha1:ABC..."/>
<dc:identifier rdf:resource="urn:sha1:DEF..."/>
</Work>

Note that the example uses a URL for the <Work> and URNs for additional identifiers, but any URI could be used in either place, sort of -- if one wanted to be nitpicky, one would say that the above example is bogus, as mysong.wav isn't in fact identified by two different SHA1 values. Perhaps the best practice would be to use some abstract, 'canonical' idenfier for the 'work' in <Work>.

Also note that the triples encoded by the example above are not the same as those encoded by

<Work about="http://example.com/mysong.wav";>
<license rdf:resource="http://creativecommons.org/licenses/by/2.0/"/>
</Work>
<Work about="urn:sha1:ABC...">
<license rdf:resource="http://creativecommons.org/licenses/by/2.0/"/>
</Work>
<Work about="urn:sha1:DEF...">
<license rdf:resource="http://creativecommons.org/licenses/by/2.0/"/>
</Work>

but rather require an application to be aware of the semantics of this use of dc:identifier. Yet another option which does produce triples identical to those produced by multiple <Work> statements is to use rdf:aboutEach (or whatever it is called, not online at the moment), but that makes things more difficult for apps that don't want to bother actually parsing RDF and IIRC is a generally frowned upon syntax.

Opionions anyone?

--
Mike Linksvayer
http://creativecommons.org/learn/aboutus/people#21





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