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Re: ISSUE-320 (Is normative SMPTE 2052 reference okay?): Is normative SMPTE 2052 reference okay? [TTML IMSC 1.0]

From: Glenn Adams <glenn@skynav.com>
Date: Sat, 24 May 2014 10:04:57 +0900
Message-ID: <CACQ=j+fNYzosLmL4d2s4fPTJBJpa7=t+KfVCQXEE23HC6-42Wg@mail.gmail.com>
To: Timed Text Working Group <public-tt@w3.org>
Firstly, I think there is no issue referencing any external document
normatively unless we as a group have particular specific concerns, such as
document stability, provenance, known IPR. Unless there is a specific
concern, I don't see it worth pursuing the matter about referencing (no
matter the source).

Secondly, we should try to make normative references specific, e.g., by
citing the specific language or section of which we wish to make normative
use. Sometimes we don't make it specific and that makes it ambiguous about
exactly what aspect of a reference is being used.

Thirdly, if we wish to adopt a feature by normative reference to its
specific syntactic/semantic specification, then we should apply the same
standards of quality and specificity to the definition of that feature,
and, if it doesn't meet our standard (however we want to consider it), then
we have a variety of options, such as redefining in TTML etc.

On Fri, May 23, 2014 at 11:44 PM, Timed Text Working Group Issue Tracker <
sysbot+tracker@w3.org> wrote:

> ISSUE-320 (Is normative SMPTE 2052 reference okay?): Is normative SMPTE
> 2052 reference okay? [TTML IMSC 1.0]
> http://www.w3.org/AudioVideo/TT/tracker/issues/320
> Raised by: Nigel Megitt
> On product: TTML IMSC 1.0
> Amongst other sections, §4.2, §6.2.1 and Appendices B.5 and C.1 make
> normative reference to SMPTE-2052-1 [1], however that document makes clear
> that it is possible that some parts of it may be subject to patent rights.
> Can we normatively reference something when we can't establish the
> licensing status of it? Note that SMPTE are not current members of this WG.
> The W3C Patent Policy FAQ says something about this, in question 32 [2] -
> to quote:
> > "32. Can a W3C Recommendation normatively refer to technology developed
> outside W3C with licensing terms that differ from those of the W3C Patent
> Policy?
> >
> > Yes. W3C Recommendations may include normative references to standards
> or technologies developed outside of W3C. However, the Working Group should
> keep in mind the importance of royalty-free implementations of Web
> standards. In the event it becomes clear that the licensing status of those
> externally-developed technologies could become a barrier to implementation
> of the technology according to the W3C Royalty-Free (RF) Licensing
> Requirements, W3C may choose not to publish the document or may launch a
> PAG."
> On this basis we (this WG) should keep in mind the implications and
> consider a change.
> One question I would ask is: is the referenced feature well defined? I
> can't see where in the SMPTE-TT document the syntax is defined that is used
> to describe the <image> element, so I'm not 100% clear what it means,
> especially because what looks like the imageType attribute is shown without
> an '=' that is present elsewhere on similar attributes (presumably a typo).
> The XSD schema is marked explicitly as non-normative.
> On that basis SMPTE 2052-1 appears to make no normative statement defining
> the contents and structure of the element on which the feature is based,
> which isn't ideal (even if a common-sense reading is probably correct).
> It's even less clear how the backgroundImage attribute is defined because
> it seems permitted to include no value, or if a value is specified it's
> listed as the undefined 'uri-specification' but seems to be a reference to
> an xml:id defined in an <image> element.
> I'm concerned that we are making a normative reference from IMSC to an
> external document that is not specified to the level of precision that we'd
> seek in a W3C recommendation.
> I'd be open to one of a variety of remediations here, including in no
> order of preference:
> * removal of the image profile altogether;
> * redefinition in IMSC of the image element and backgroundImage attribute
> in the relevant ttml namespace;
> * requesting that SMPTE edits 2052-1 to make the definitions clearer and
> (optionally and preferably) to clarify the licensing status so that we can
> continue to reference it;
> * other options I haven't thought of.
> Incidentally, IMSC 1 §B.1 suggests that all the subsequent feature
> extension designations are in the TTML extension namespace but this is not
> true for B.5 which is in the SMPTE-TT namespace (which by the way happens
> to return a "Not Found" response page, for both the one in the text in the
> 2052-1 document §5.8 or the other different one in Table 11).
> [1] https://www.smpte.org/sites/default/files/st2052-1-2010.pdf
> [2] http://www.w3.org/2003/12/22-pp-faq.html#outside-normative-ref
Received on Saturday, 24 May 2014 01:05:46 UTC

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