Re: AW: Definition of ma:fragments and ma:namedFragments

Hi Werner,

Thanks for the clarifications. I indeed completely misunderstood what 
was the semantics of these two properties :-)

> The rationale behind the two elements is the following: ma:fragments
> is meant to contain a list of fragments (of any type) of that media
> resource, these could be chapters, scenes, clips a user likes, etc.

By fragments, I assume you mean a subpart of the media resource. Your 
ma:fragments property seem then very close to what M3U or ROE (Rich Open 
multitrack media Encapsulation) formats specify, correct?
Do you really mean a list? Does the order matter? Can we have duplicates?

So you would have something like:
  http://www.example.com/myvideo.ogv ma:fragments ( :fragment1, 
:fragment2, ...) ?

> The API can then be used to query annotations of the fragment, so
> ma:fragment links different granularities of annotations. These
> fragments could also be named fragments, with all the issues you have
> pointed out.

I still don't understand how these fragments are referred to? By URI ref?

> The reason to have ma:namedFragments is different. It addresses the
> discovery problem that you mentioned, i.e. to determine what the
> valid range values for each type of fragment identifier is. The ma
> properties allow to answer this query for temporal, spatial and track
> fragments by using the appropriate technical properties.

How? Could you provide an example?

> The issue I raised yesterday was not related to labels from container
> formats, but to identifiers of fragments in metadata documents that
> are accessed using the media annotation API. Assume you have an
> MPEG-7 document, which describes the shot structure of a video. Each
> VideoSegment can have an ID, so that, given the media resource is
> http://foo.com/video a shot could be http://foo.com/video#1, which is
> an identifier for this fragment and a URI, but not a media fragment
> URI.

http://foo.com/video#1 is a valid URI but how do you expect to 
dereference it? 1 is not a valid XML id as you may have guessed.

You're saying that http://foo.com/video#1 identifies a particular shot 
with a video. Why not identifying this segment with the media fragment 
URI that actually defines the temporal boundary of this shot?

> In this case ma:fragments should contain http://foo.com/video#1,
> and when requesting the ma:location property of this fragment one
> would get e.g. http://foo.com/video/video.mpg#t=10,20

So you would have;
  <video> ma:fragments (<video#1>, <video#2, ...) .
  <video#1> ma:location http://foo.com/video/video.mpg#t=10,20 .
  <video#1> foaf:primaryTopic dbpedia:love .
?

> I hope this clarifies things a bit.

Partly ;-)

   Raphaël

-- 
Raphaël Troncy
EURECOM, Multimedia Communications Department
2229, route des Crêtes, 06560 Sophia Antipolis, France.
e-mail: raphael.troncy@eurecom.fr & raphael.troncy@gmail.com
Tel: +33 (0)4 - 9300 8242
Fax: +33 (0)4 - 9000 8200
Web: http://www.cwi.nl/~troncy/

Received on Thursday, 1 October 2009 19:48:16 UTC