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Discovery of track and named fragment names

From: Davy Van Deursen <davy.vandeursen@ugent.be>
Date: Wed, 18 Nov 2009 13:31:03 +0100
To: <public-media-fragment@w3.org>
Message-ID: <005301ca684a$fe8ea3f0$fbabebd0$@vandeursen@ugent.be>
Hi all,


To retrieve track and named fragments, we need to know the name of the
fragment. Until now, we didn't talk much about how to discover these names
(at client side). When implementing scenarios such as [1], I can image that
a certain way of discovering these names will be necessary. 


In order to discover names of tracks and named fragments, clients can
download a file describing the organization of the corresponding media
resource in terms of tracks and named fragments. Formats that can be used
for this purpose are for example ROE [2], MPEG-21 DID [3], . 


I implemented, by means of an experiment, the ROE format into our NinSuna
platform [4]. More specifically, if you want to get more information
regarding the structure of the media resource
http://schutz.elis.ugent.be:8080/DownloadServlet/fragf2f.ogv, you can
request this resource through HTTP using 'application/roe' in the accept
header (don't think this mime type actually exists :-)):


GET /DownloadServlet/fragf2f.ogv HTTP/1.1

Host: schutz.elis.ugent.be:8080

Accept: application/roe


The answer includes then the following ROE content (which allows us to
discover the names of the tracks: 'ogg_1' and 'ogg_2'):


<ROE xmlns="http://www.xiph.org/roe1.0">


    <track id="ogg_1" provides="video">

      <mediaSource id="ogg_1_source" content-type="video/theora"
_1'" />


    <track id="ogg_2" provides="audio">

      <mediaSource id="ogg_2_source" content-type="audio/vorbis"
_2'" />





Any comments on this way of working? Moreover, should we specify a method
for discovering track and named fragments as normative in the spec? I think
we should have at least an informative section regarding this topic .


Best regards,





[2] http://wiki.xiph.org/ROE 

[3] http://www.chiariglione.org/MPEG/technologies/mp21-did/ 




Davy Van Deursen

Ghent University - IBBT

Faculty of Engineering

Department of Electronics and Information Systems 

Multimedia Lab

Gaston Crommenlaan 8 bus 201

B-9050 Ledeberg-Ghent


t: +32 9 33 14893

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t secr: +32 9 33 14911

e:  <mailto:davy.vandeursen@ugent.be> davy.vandeursen@ugent.be

URL:  <http://multimedialab.elis.ugent.be/dvdeurse>


Received on Wednesday, 18 November 2009 12:31:48 UTC

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