[Wasabi] Kicking of the Metadata spec - brainstorm

[Jos van den Oever]

2007/2/20, Jon Phillips <jon at rejon.org>:
> On Tue, 2007-02-20 at 15:10 +0100, Jos van den Oever wrote:
> > 2007/2/20, Mikkel Kamstrup Erlandsen <mikkel.kamstrup at gmail.com>:
> > > 2007/2/20, Jos van den Oever <jvdoever at gmail.com>:
> > >
> > > > 2007/2/19, Mikkel Kamstrup Erlandsen <mikkel.kamstrup at gmail.com>:
> > > > > Let's get the ball rolling on the metadata spec. This first period will
> > > just
> > > > > be *brainstorming*, so let's try and avoid the nitty gritty details for
> > > now.
> > > > >
> > > > >  ** What we need:
> > > > >
> > > > >   Fields)  Metadata field names and descriptions for *desktop* objects
> > > > >
> > > > >   Types) A type grouping of metadata fields to be used in user search
> > > > > language. Example types could be "Email", "Image", "Audio", etc.
> > > > >
> > > > >   API) A dbus api to get/set metadata
> > > > >
> > > > >   ?Tag/Emblem) Tagging/Keywords/Emblems
> > > > >
> > > > >  ** Starting points/References:
> > > > >  - Adobe XMP:
> > > > >
> > > http://partners.adobe.com/public/developer/en/xmp/sdk/XMPspecification.pdf
> > > > >
> > > > >  - Shared Metadata Spec:
> > > > >
> > > http://freedesktop.org/wiki/Standards_2fshared_2dfilemetadata_2dspec
> > >
> > > > >  - Tracker metadata api:
> > > > >
> > > http://svn.gnome.org/viewcvs/tracker/trunk/data/tracker-introspect.xml?view=markup
> > >
> > > > >
> > > > >  - Spotlight Metadata Spec:
> > > > >
> > > http://developer.apple.com/documentation/Carbon/Reference/MetadataAttributesRef/Reference/CommonAttrs.html
> > >
> > > > >
> > > > >  - Shared Emblem Spec:
> > > > >
> > > http://freedesktop.org/wiki/Standards_2fdesktop_2demblem_2dspec
> > > > >  - Others ideas? Nepomuk-specs? Beagle-specs?
> > > > >
> > > > >  ** My thoughts:
> > > > > Regarding Fields): To prevent death-by-1000-page-spec I suggest we keep
> > > the
> > > > > field names to a core set of commonly used attributes. Ie not like
> > > Apples
> > > > > spotlight spec (see above) which defines every known property in the
> > > > > universe. When things move on, teams with expert knowledge can refine
> > > > > extensions to this spec. Fx a Wasabi Photography Metadata spec could be
> > > > > hashed out by people in the know (which could just be EXIF, but I'm not
> > > the
> > > > > photography expert).
> > > > >
> > > > > Regarding Types): There are some suggestions in the top of the Tracker
> > > api
> > > > > link above. Regarding these I think we should leave the VFS* types out,
> > > and
> > > > > only use single-word type names (Ie no spaces).
> > > > >
> > > > > On the API): Obviously we getters and setters. They probably need to
> > > operate
> > > > > on uris. There probably needs to be some search functionality in here
> > > too
> > > > > since we probably shouldn't assume that the indexer and metadata server
> > > are
> > > > > the same.
> > > > >
> > > > > Tagging/Emblems: If you ask me they should be "just another type of
> > > > > metadata". When the metadata spec matures a bit we can evaluate if it
> > > needs
> > > > > it's own api to make things easier (and allow for dedicated tagging
> > > > > services).
> > > >
> > > > Hi All,
> > > >
> > > > First I'd like to point to the original mail I sent on this subject.
> > > > It already contained a relatively simple spec framework. That is, not
> > > > attribute names, but a way to define them, type them and check them.
> > > > There was also some code attached to do allow testsets to check the
> > > > correctness of metadata extraction from files. Hence the title of the
> > > > mail: 'mimetype standardization by testsets'. I still stand by this
> > > > idea.
> > >
> > >
> > > Sorry Jos, how could I miss this out. For reference - here's the original
> > > thread:
> > > http://lists.freedesktop.org/archives/xdg/2006-October/008682.html
> > Ah yes, thanks for adding the link, I forgot it.
>
> Yes, excellent.
>
> > >
> > > > Here is an idea for a simple proposal.
> > > >
> > > > - Each metadata type is identified by a URI. E.g.
> > > >
> > > http://www.freedesktop.org/metadata/xhtml1/title.
> > > > - For each URI there will be human readable descriptions in every
> > > > language and keywords in every language. I will use the keyword in the
> > > > further description mixed with the URI.
> > >
> > >
> > > I like this idea as such. I can't readily see how it intermixes with known
> > > widespread standards such as DC though..?
>
> Yes, I think this approach is good as well. My main interest is in
> getting proper licensing fields into this spec (I work for creative
> commons ;) Maybe now is not the time to throw my 2 cents into this, but
> this URI approach meshes well with other standards...
>
> > DC also uses URIs to identify metadata types. It does not define much
> > more than that though. This is too little for our needs. Within RDF
> > Schema it is also customary to use URIs for type identification.
>
> Agree, but how would you propose to mend this gap?
I see two possibilities: either we add a mechanism with aliases. We
could for example say that we have a group of types that matches the a
certain DC entry. Since metadata types may appear in multiple groups
this is a flexible method that does not make us depend too much on DC
but lets us interact with it.

Or we use the DC entries as parents. We then say that the DC types
have xml schema type xs:anySimpleType and set the other properties as
undefined as possible too.

>
> Is there spec on a wiki somewhere to help hammer this out?
>
> Jon
>
>
>
> --
> Jon Phillips
>
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