W3C home > Mailing lists > Public > uri@w3.org > July 2004

Request feedback on fragment identifiers

From: Myriam Amielh <myriam.amielh@cisra.canon.com.au>
Date: Mon, 05 Jul 2004 10:31:20 +1000
Message-ID: <40E8A158.6030003@cisra.canon.com.au>
To: uri@w3.org

Dear uri experts,

Sorry if you have already got that message, apparently our previous 
message was lost and could not be uploaded to the archive so we need to 
send it again.

MPEG-21 is currently running a Core Experiment for discussing/evaluating 
some fragment identifiers. We've been contributing with an audiovisual 
addressing scheme designed for a large range of non-XML MIME Types.

Prior of all, MPEG experts need to make sure that defining such a syntax 
for fragment identifiers would not be conflicting with any RFC 
specification. We've been examining RFC2396 along with the 
Internet-Draft RFC2396bis to validate our approach, but we believe that 
URI experts feedback is now required for going further.

The underlying idea is to design an addressing scheme for audiovisual 
content, able to address spatio-temporal fragments, that could be used 
for audiovisual resources that does not have an authoritative addressing 

The benefits to industry for having a generic fragment identifier would 
be to close the gap left by the many AV Internet Media Types that do not 
specify an authoritative interpretation for fragment identifiers. 
However, this would not prevent any new authoritative interpretation to 
be defined in the future.

We believe this approach is in line with some discussions we read on W3C 
uri forum:

For that, MPEG-21 could possibly define a fragment identifier for MPEG 
MIME types such as video/mpeg, audio/mpeg, and so forth. Then MPEG could 
also propose a Best Current Practise for other MIME-types which do not 
have an addressing scheme yet: The BCP could suggest the use of a 
generic fragment identifier scheme (at least, in MPEG-21) for any 
content type as long as there is no other authoritative addressing 
scheme. The BCP could also point to existing schemes, as for instance 
for PDF or XML resources.

Whenever a new authoritative scheme pops up, an application that 
previously supported the mp scheme could either continue using it or be 
upgraded to support the authorative scheme, especially if it is able to 
address fragments that the mp scheme cannot.

We didn't see anything in the RFCs that may exclude the use of a second 
fragment interpretation scheme other than an authoritative one that is 
registered with a particular MIME-type. However, this is an assertion we 
would like to cross-check with URI experts.

We are looking forward to reading your feedback on this,
Best regards
Received on Wednesday, 7 July 2004 14:50:20 UTC

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