W3C home > Mailing lists > Public > public-tt@w3.org > May 2014

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

From: Nigel Megitt <nigel.megitt@bbc.co.uk>
Date: Fri, 23 May 2014 15:53:01 +0000
To: Michael Dolan <mdolan@newtbt.com>, "'Timed Text Working Group'" <public-tt@w3.org>
Message-ID: <CFA52A89.1E443%nigel.megitt@bbc.co.uk>

You seem to be generalising from a specific point! I do not question the
pedigree of SMPTE's patent policy, merely note that the license status of
SMPTE ST 2502-1 is clearly stated as being inconclusive within that
particular document. And I make specific reference to the document
referenced by our document-in-draft.

As a point of fact EBU is a member of the WG with 2 representatives,
furthermore the TTWG has so far made no recommendations that normatively
reference an EBU document. If hypothetically EBU or any other member were
to make a contribution to the WG the licensing terms for this are clear
and pre-agreed.

Since SMPTE is not a member of, and has not made a contribution to, the WG
for IMSC it does not fall under those terms. It is a reasonable action to
check that we are taking the correct steps in making the normative
reference that is the subject of this issue, for this particular
deliverable. I can only assume that for all other recommendations that
make normative reference to an external document a similar check was made
- but it is not our concern here.

I very much welcome SMPTE's continuing active interest, however this does
not remove our need to take reasonable care.

You will note that one of the options I listed was indeed to communicate
with SMPTE regarding the issues I've identified.

Kind regards,


On 23/05/2014 16:28, "Michael Dolan" <mdolan@newtbt.com> wrote:

>Mr. TTWG Chair-
>I must say that I am surprised that you singularly question the pedigree
>of SMPTE's patent policy and the license status of SMPTE ST 2502-1.
>Following this logic, then we better immediately initiate review of: 1)
>all external normative references in TTML1, TTML2 and IMSC which
>includes: ISO, IEC, ITU, Unicode, US Government, and others); and 2) all
>W3C references to SMPTE standards, which includes SMIL, and of course
>TTML1 and TTML2.
>Right, "SMPTE" is not a member of this WG any more than "EBU" or any
>other SDO is. However, had you asked or taken note of earlier
>communications between the organizations, you will find that SMPTE has
>for a long time a formal liaison with W3C [1] and taken an active
>interest in the work of this WG.
>If you feel 2052-1 is lacking in technical precision, SMPTE welcomes your
>       Mike
>       W3C Liaison to SMPTE
>[1] http://www.w3.org/2001/11/StdLiaison
>-----Original Message-----
>From: Timed Text Working Group Issue Tracker
>Sent: Friday, May 23, 2014 7:45 AM
>To: public-tt@w3.org
>Subject: ISSUE-320 (Is normative SMPTE 2052 reference okay?): Is
>normative SMPTE 2052 reference okay? [TTML IMSC 1.0]
>ISSUE-320 (Is normative SMPTE 2052 reference okay?): Is normative SMPTE
>2052 reference okay? [TTML IMSC 1.0]
>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
>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

This e-mail (and any attachments) is confidential and
may contain personal views which are not the views of the BBC unless specifically stated.
If you have received it in
error, please delete it from your system.
Do not use, copy or disclose the
information in any way nor act in reliance on it and notify the sender
Please note that the BBC monitors e-mails
sent or received.
Further communication will signify your consent to
Received on Friday, 23 May 2014 15:53:34 UTC

This archive was generated by hypermail 2.4.0 : Friday, 17 January 2020 17:43:35 UTC