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Re: Track kinds

From: David Singer <singer@apple.com>
Date: Wed, 15 Jun 2011 17:00:40 -0700
Cc: Philippe Le Hegaret <plh@w3.org>, Mark Watson <watsonm@netflix.com>, Paul Cotton <Paul.Cotton@microsoft.com>, Janina Sajka <janina@rednote.net>, "Judy Brewer <jbrewer@w3.org> (jbrewer@w3.org)" <jbrewer@w3.org>, HTML Accessibility Task Force <public-html-a11y@w3.org>
Message-id: <55258C0D-84AA-4A7C-BF7A-53E32F5768AF@apple.com>
To: Silvia Pfeiffer <silviapfeiffer1@gmail.com>

On Jun 7, 2011, at 14:58 , Silvia Pfeiffer wrote:

> On Wed, Jun 8, 2011 at 5:47 AM, Philippe Le Hegaret <plh@w3.org> wrote:
>> On Tue, 2011-06-07 at 12:41 -0700, Mark Watson wrote:
>>> Hi Silvia,
>>> 
>>> 
>>> I like your proposed reply, except this last part.
>>> 
>>> On Jun 5, 2011, at 10:34 PM, Silvia Pfeiffer wrote:
>>> 
>>>> There will be no URN to specify these names.
>>> 
>>> 
>>> Specifying a URN is no more than giving a permanent machine-readable
>>> name to the list of values (not, it's not a URN for each individual
>>> value). It has not cost (URNs are an infinite resource) and has value
>>> in that it enables the kinds we specify to be referred to in other
>>> protocols, specifically DASH.
>> 
>> I think that Silvia meant to say there is no need for a URN for the
>> HTML5 track kinds. Those will be included in the HTML5 specification.
> 
> Indeed. :-)
> 
> Specifically, according to RFC3305 contemporary view, there is no need
> to specify a URN when there are well defined URIs available. They
> identify the objects sufficiently. Interestingly also, the set or
> registered URN schemes at IANA does not include a W3C namespace, see
> http://www.iana.org/assignments/urn-namespaces/urn-namespaces.xml .
> It's probably because the W3C has a well defined URI naming scheme.
> So, referencing the HTML5 specification and the section therein where
> the kind names are defined should be sufficient.


I think there is a real misunderstanding here.

The 3G/MPEG spec. ( at the moment) says that the 'role' names are scoped by a URI that identifies the specification which those names come from.  This does, indeed, allow 3G and/or MPEG (or anyone else) to define new names.  What they want to do, however, is say that for the common cases, covered by HTML5, please use the HTML5 names, and the identifying URI for that namespace is XXX.

Clearly, since the W3C owns the spec., it looks tidier if the identifying URI is also the W3C's.  3G or MPEG could define a URI
urn:mpeg:stuff:whatever:w3c:track-kinds

but it might be best if the HTML spec. said "where these names are used in other contexts, the URI urn:w3c:html:track-kinds" identifies this name-set.

David Singer
Multimedia and Software Standards, Apple Inc.
Received on Thursday, 16 June 2011 00:02:05 GMT

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