Disposition of comments for Timed Text DFXP Second Last Call

This version
http://www.w3.org/2005/03/21/DFXP-2ND-LastCallResponses.html
Editor:
Thierry Michel, W3C

Copyright ©2006 W3C® (MIT, ERCIM, Keio), All Rights Reserved. W3C liability, trademark and document use rules apply.


These are the collected 2nd Last Call comments on Timed Text (TT) Authoring Format 1.0 Distribution Format Exchange Profile (DFXP), Second Last Call WD which were sent to the public Timed Text mailing list public-tt@w3.org (archives) and responses to those comments.

1- The DFXP Second LC review annoucement was sent to the public-tt@w3.org and chairs@w3.org list on 27th Apr 2006.

The 12 (2nd Last Call) comments have the following status (status on 18 Sept 2006):

Second LC Public Comments are as follows:

  1. Registration of application/ttaf+xml [Status: Comment answered / agreed by Requestor]
  2. Processor Conformance [Status: Comment answered / agreed by Requestor]
  3. Core Attributes, id and xml:id [Status: Comment answered / agreed by Requestor]
  4. PAL and ttp:frameRateMultiplier [Status: Comment answered / agreed by Requestor]
  5. br semantics [Status: Comment answered / agreed by Requestor]
  6. Color fidelity during transcoding [Status: Comment answered / agreed by Requestor]/
  7. Words and spaces [Status: Comment answered / agreed by Requestor]
  8. char [Status: Comment answered / agreed by Requestor]
  9. metadata and Dublin Core [Status: Comment answered / agreed by Requestor]
  10. SVG 1.1 in Informative References [Status: Comment answered / agreed by Requestor]
  11. Some general remarks about TimedText DFXP [Status: Comment answered / no reaction from Requestor]
  12. Re: Color fidelity during transcoding (hook claiming that there is an accessibility topic) [Status: Comment answered / no reaction from Requestor]

Notification of these Last Call responses were sent to all of the commenters and the Timed text list: http://lists.w3.org/Archives/Public/public-tt/

2- The DFXP FIRST LC review annoucement was sent to the public-tt@w3.org and chairs@w3.org list on March 21st 2005.

The status of the Disposition of comments for Timed Text DFXP FIRST Last Call are as follows:

The 15 (1st Last Call) comments have the following status (status on 15 Sept 2006):


Issue 01: Registration of application/ttaf+xml

Comment:

 Hello public-tt,

I didn't see a registration template for the application/ttaf+xml media type in 
http://www.w3.org/TR/2006/WD-ttaf1-dfxp-20060427/

Did I miss it? If not, please ensure that the next published specification includes such an appendix and that a textual copy of it is sent to the ietf-types@iana.org list inviting comments on the proposed registration.

For details of the registration procedure in the IETF standards tree for W3C-produced media types, please see:
  http://www.w3.org/2002/06/registering-mediatype
In the section entitled
  New Procedure: Registration template in spec, no RFC

For examples of such a template, please see for example
  http://www.w3.org/TR/2004/WD-wsdl20-20040803/#ietf-draft
  http://www.w3.org/TR/SVGMobile12/mimereg.html

-- Chris Lilley mailto:chris@w3.org Interaction Domain Leader Co-Chair, W3C SVG Working Group W3C Graphics Activity Lead Co-Chair, W3C Hypertext CG 
Timed Text WG Response:
W3C TT WG thank you for your comments on DFXP. TT WG has the following responses to these comments:

TTWG Response: Will add template.

The resolution is archived at:
http://lists.w3.org/Archives/Member/member-tt/2006Jun/0033.html

TTWG response agreed by Requestor
http://lists.w3.org/Archives/Public/public-tt/2006Aug/0004.html


Issue 02: Processor Conformance

Comment:

 Hello public-tt,

section 3.2 Processor Conformance states:

  If the processor claims to support presentation processing in order to
  produce a rendition of TT AF content on a visual medium, then it must
  implement the region and line layout semantics defined by 9.3 Region
  Layout and Presentation and 9.4 Line Layout, respectively. In
  addition, the processor should satisfy the user agent accessibility
  guidelines specified by [UAAG].

section 9.3.2 Synchronic Flow Processing states:

  for each TT AF style property attribute in some computed style
  specification set that has no counterpart in [XSL 1.0], map that
  attribute directly through to the relevant formatting object produced
  by the input TT AF content element to which the style property
  applies;

My question - it is not clear whether an XSL-FO processor which claims
to be a TTAF- DFXP processor and claims to support presentation
processing, but does not support any TT AF style properties that are
not already in XSL 1.0, is a Conformant Processor per 3.2.

Please clarify. If it would be conformant, are the extra TT AF style
properties ignored?

-- 
 Chris Lilley                    mailto:chris@w3.org
 Interaction Domain Leader
 Co-Chair, W3C SVG Working Group
 W3C Graphics Activity Lead
 Co-Chair, W3C Hypertext CG 
Timed Text WG Response:
W3C TT WG thank you for your comments on DFXP. TT WG has the following responses to these comments:

TTWG Response: The intention is that the presentation processing defined by DFXP that extends beyond or differs from XSL 1.0 also be required by a conformant presentation processor. That is, a strictly XSL 1.0 conformant formatter would not be wholly adequate. The text will be clarified to make this intention more clear.

The resolution is archived at:
http://lists.w3.org/Archives/Member/member-tt/2006Jun/0033.html

TTWG response agreed by Requestor
http://lists.w3.org/Archives/Public/public-tt/2006Aug/0003.html


Issue 03: Core Attributes, id and xml:id

Comment:

 Hello public-tt,

http://www.w3.org/TR/2006/WD-ttaf1-dfxp-20060427/

lists the Core Attributes as id, xml:lang, xml:space

Given the difficulty of determining that an id is of type ID in the absence of a DTD or Schema, and given that external DTD subsets are optional in XML 1.0 and 1.1, and given that xml:id is intended precisely to provide an unambiguous ID attribute, could you please explain why the Core Attributes are not

xml:id, xml:lang, xml:space ?


http://www.w3.org/TR/2005/REC-xml-id-20050909/
xml:id Version 1.0
W3C Recommendation 9 September 2005


-- 
 Chris Lilley                    mailto:chris@w3.org
 Interaction Domain Leader
 Co-Chair, W3C SVG Working Group
 W3C Graphics Activity Lead
 Co-Chair, W3C Hypertext CG 
Timed Text WG Response:
W3C TT WG thank you for your comments on DFXP. TT WG has the following responses to these comments:

TTWG Response: Accepted. id will be replaced with xml:id.

The resolution is archived at:
http://lists.w3.org/Archives/Member/member-tt/2006Jun/0033.html

TTWG response agreed by Requestor
http://lists.w3.org/Archives/Public/public-tt/2006Aug/0006.html


Issue 04: PAL and ttp:frameRateMultiplier

Comment:

 Hello public-tt,

http://www.w3.org/TR/2006/WD-ttaf1-dfxp-20060427/
In 6.2.4 ttp:frameRateMultiplier the Note is very useful to explain the
somewhat arcane NTSC frame rate.

Is it correct to state that PAL (apart from PAL/M) has a ttp:frameRate
of 25 and a ttp:frameRateMultiplier of 1:1 ? If so, it might still be
useful to say so in a second Note and if not, it would be valuable to
explain the PAL frameRateMultiplier in a Note.

-- 
 Chris Lilley                    mailto:chris@w3.org
 Interaction Domain Leader
 Co-Chair, W3C SVG Working Group
 W3C Graphics Activity Lead
 Co-Chair, W3C Hypertext CG 
Timed Text WG Response:
W3C TT WG thank you for your comments on DFXP. TT WG has the following responses to these comments:

TTWG Response: Yes, apart from PAL/M, it is as you indicate. A 2nd note will be added.

The resolution is archived at:
http://lists.w3.org/Archives/Member/member-tt/2006Jun/0033.html

TTWG response agreed by Requestor
http://lists.w3.org/Archives/Public/public-tt/2006Aug/0002.html


Issue 05: br semantics

Comment:

 Hello public-tt,

http://www.w3.org/TR/2006/WD-ttaf1-dfxp-20060427/
Section 7.1.7 br states:

  The br element denotes an explicit line break.

  When presented on a visual medium, the presence of a br element must
  be interpreted as a force line break

Is that a break as in a carriage return (move to start of line), a line
feed (move down one line) or both? In particular, does a sequence of two
or more br elements produce a different visual effect to a single br?

-- 
 Chris Lilley                    mailto:chris@w3.org
 Interaction Domain Leader
 Co-Chair, W3C SVG Working Group
 W3C Graphics Activity Lead
 Co-Chair, W3C Hypertext CG 
Timed Text WG Response:
W3C TT WG thank you for your comments on DFXP. TT WG has the following responses to these comments:

TTWG Response: It is intended to have the same effect as the ASCII control codes CR followed by NL on a teletype device. Therefore, two br elements will indeed produce a different effect than a single br element on a compliant presentation processor. Additional language that clarifies this intention will be added.

The resolution is archived at:
http://lists.w3.org/Archives/Member/member-tt/2006Jun/0033.html

TTWG response agreed by Requestor
http://lists.w3.org/Archives/Public/public-tt/2006Aug/0005.html


Issue 06: Color fidelity during transcoding

Comment:

 Hello public-tt,

 I'm pleased to note that all colors are specified in the sRGB color space.

Does TT AF DFXP express any conformance requirement regarding the
fidelity of the colors when converting to and from DFXP? I am thinking
not only of chrominance and white-point adaptation effects - which
should be minimal for modern equipment given that sRGB uses the 709
phosphor chromaticities - but more for differing assumptions on headroom
footroom, allowed colors, and corrections for flare, scene brightness,
surround and other viewing condition effects.

There is a useful discussion at
http://www.srgb.com/srgb709compatibility.html
How are sRGB and ITU-R BT.709-2 compatible?

Basically I am wondering how much guidance should be given in this area
such that reliable interchange between differing systems can be
achieved.

-- 
 Chris Lilley                    mailto:chris@w3.org
 Interaction Domain Leader
 Co-Chair, W3C SVG Working Group
 W3C Graphics Activity Lead
 Co-Chair, W3C Hypertext CG 
Timed Text WG Response:
W3C TT WG thank you for your comments on DFXP. TT WG has the following responses to these comments:

TTWG Response: Other than the use of sRGB, DFXP intentionally does not specify conformance requirements on fidelity of color conversion from a source document to a DFXP document. At this point, we have not identified any requirements that would suggest adding this level of specificity.

The resolution is archived at:
http://lists.w3.org/Archives/Member/member-tt/2006Jun/0033.html

TTWG response agreed by Requestor
http://lists.w3.org/Archives/Public/public-tt/2006Aug/0015.html


Issue 07: Words and spaces

Comment:

 Hello public-tt,

In section 8.3.7 <flowFunction>

 The dynamic flow unit word must be interpreted as being dependent upon
 the language or writing system of the affected content. If the language
 or writing system is unknown or unspecified, then word is interpreted
 as follows:

   1. If the affected content consists solely or mostly of Unified CJK
   Ideographic characters or of characters of another Unicode character
   block that are afforded similar treatment to that of Unified CJK
   Ideographic characters, then word is to be interpreted as if
   character were specified.
   
   2. Otherwise, word is to be interpreted as denoting a sequence of one
   or more characters that are not interpreted as an XML whitespace
   character.

Noting the "must" which is a testable conformance requirement, do the
following paragraphs contain one word or two?

<p>Hello&#x3000;World</p>
<p xml:lang="en">Hello&#x3000;World</p>
<p xml:lang="en">Hello&#x2004;World</p>
<p xml:lang="ja">Hello&#x3000;World</p>
<p xml:lang="ja">Hello&#x2004;World</p>
<p xml:lang="ja">Masayasu Ishikawa</p>

For a list of Unicode space characters, see for example
http://www.cs.tut.fi/~jkorpela/chars/spaces.html


-- 
 Chris Lilley                    mailto:chris@w3.org
 Interaction Domain Leader
 Co-Chair, W3C SVG Working Group
 W3C Graphics Activity Lead
 Co-Chair, W3C Hypertext CG
Timed Text WG Response:
W3C TT WG thank you for your comments on DFXP. TT WG has the following responses to these comments:

TTWG Response: Regarding your question, it depends upon whether the language or writing system is unknown or unspecified. If either of these cases hold, then, according to rule 2 above, each of your examples except the last would be interpreted as one word. The last would be interpreted as two words, presuming that the ' ' between "Masayasu" and "Ishikawa" is represented as #x20. In contrast, if the language or writing system is known, e.g., if xml:lang="en" is specified on the root element (and no override appears), then a word unit is specified in accordance of the rules of that language or writing system. DFXP does not specify these latter rules in an interoperable manner (as Unicode also does not specify).

The resolution is archived at:
http://lists.w3.org/Archives/Member/member-tt/2006Jun/0033.html

TTWG response agreed by Requestor
http://lists.w3.org/Archives/Public/public-tt/2006Aug/0009.html


Issue 08: char

Comment:

 Hello public-tt,

 8.3.14 <string>

  A <string> expression consists of a sequence of characters where no
  character is a whitespace or quotation delimiter character.
  
  Syntax Representation � <string>

  <string>
    : ( char - { S | "\"" | "\'" } )+

I did not see a definition of 'char'. Please define the token char,
preferably by reference to Unicode, appropriate productions from XML 1.0
or XML1.1, or CharMod part 1: Fundamentals.

-- 
 Chris Lilley                    mailto:chris@w3.org
 Interaction Domain Leader
 Co-Chair, W3C SVG Working Group
 W3C Graphics Activity Lead
 Co-Chair, W3C Hypertext CG
Timed Text WG Response:
W3C TT WG thank you for your comments on DFXP. TT WG has the following responses to these comments:

TTWG Response: Accepted. The token "char" will be formally defined by referring to the references you cite.

The resolution is archived at:
http://lists.w3.org/Archives/Member/member-tt/2006Jun/0033.html

TTWG response agreed by Requestor
http://lists.w3.org/Archives/Public/public-tt/2006Aug/0008.html


Issue 09: metadata and Dublin Core

Comment:

 Hello public-tt,

 12.1 Element Vocabulary


Many (but not all) of the elements seem to have Dublin Core equivalents. 
Was Dublin Core considered and rejected for this type of metadata? 

-- 
 Chris Lilley                    mailto:chris@w3.org
 Interaction Domain Leader
 Co-Chair, W3C SVG Working Group
 W3C Graphics Activity Lead
 Co-Chair, W3C Hypertext CG
Timed Text WG Response:
W3C TT WG thank you for your comments on DFXP. TT WG has the following responses to these comments:

TTWG Response:

Dear Chris,

I see that I failed to forward the response of the TT WG to your question (below) as follows:

<quote>
Yes, Dublin Core vocabulary was carefully reviewed for possible use, and the decision of the group was that the intended use was sufficiently different to warrant adoption. This comment was also received during the 1st Last Call, the response to which was recorded at: http://www.w3.org/2005/03/21/DFXPLastCallResponses.html#Issue9.
</quote>

You may also note the recent thread [1] on this reflector with Al Gilman, who had originally raised the same question during the 1st Last Call of DFXP [2]. I believe that Al has agreed with our final conclusion that:

"we found the analogy to SVG so compelling that we based these on that"

[1] http://lists.w3.org/Archives/Public/public-tt/2006Sep/0004.html
[2] http://lists.w3.org/Archives/Public/public-tt/2005Apr/0038.html

If you would, please indicate if these responses represent a satisfactory conclusion to your comment.

Regards,

Glenn

The response is archived at:

http://lists.w3.org/Archives/Public/public-tt/2006Sep/0006.html

TTWG response agreed by Requestor
http://lists.w3.org/Archives/Public/public-tt/2006Sep/0009.html


Issue 10: SVG 1.1 in Informative References

Comment:

 Hello public-tt,

 In the informative references

SVG 1.0
    Jon Ferraiolo, Editor, Scalable Vector Graphics (SVG) 1.0, 
    W3C Recommendation, 04 September 2001. 
    (See http://www.w3.org/TR/2001/REC-SVG-20010904/.)

Please note that SVG 1.0 is replaced by SVG 1.1: the 'latest version' link in SVG 1.0, http://www.w3.org/TR/SVG/ leads to SVG 1.1

Please replace this reference by

SVG 1.1
    Jon Ferraiolo, 藤沢 淳 (FUJISAWA Jun), Dean Jackson, Editors,
    Scalable Vector Graphics (SVG) 1.1 Specification,
    W3C Recommendation 14 January 2003
    (See http://www.w3.org/TR/2003/REC-SVG11-20030114/ )


-- 
 Chris Lilley                    mailto:chris@w3.org
 Interaction Domain Leader
 Co-Chair, W3C SVG Working Group
 W3C Graphics Activity Lead
 Co-Chair, W3C Hypertext CG
Timed Text WG Response:
W3C TT WG thank you for your comments on DFXP. TT WG has the following responses to these comments:

TTWG Response: Accepted. Will update as suggested.

The resolution is archived at:
http://lists.w3.org/Archives/Member/member-tt/2006Jun/0033.html

TTWG response agreed by Requestor
http://lists.w3.org/Archives/Public/public-tt/2006Aug/0007.html


Issue 11: Some general remarks about TimedText DFXP

Comment:

Dear all,

Enclosed you will find a PDF document containing some general remarks about
TimedText DFXP.
See
http://lists.w3.org/Archives/Public/public-tt/2006Jul/att-0011/Some_general_remarks_about_Timed_Text.pdf

Best regards,
Samuel Cruz-Lara
LORIA / INRIA Lorraine
Timed Text WG Response:

Thank you for considering the DFXP formulation of the Timed Text Authoring Format. Perhaps some background will be useful for better understanding:

1. the requirement for parallel language representations of a single logical document in the context of a single document instance was discussed and included in TTAF1.0 requirements (see R201); explicit support for this was ruled out in DFXP, which is intended to satisfy a high priority subset of requirements that relate to interchange of legacy content; the conclusion of the WG was that it would be better to use multiple DFXP document instances to represent multiple language representations; it remains feasible to define a more complete profile of TTAF1.0 in the future, such as the AFXP (Authoring Format Exchange Profile) that was considered in earlier drafts, but, at this time, has taken a back seat due to insufficient member support;

2. no discussion occurred on the issue of how to explicitly synchronize content between multiple language instances; this potential requirement (which may be implied in your work) was not submitted for WG consideration;

3. requirement R203, regarding natural language association granularity, was intended to support only course grained linguistic attribution, and, indeed, xml:lang satisfied this basic requirement; it remains possible for a user of DFXP to make use of the ttm:role attribute while using extension tokens (i.e., "x-*") to denote application specific bindings;

4. the TTWG did perform a cursory review of the functionality defined by TEI (text encoding initiative) that could have formed the basis for additional requirements or solutions, however, no consensus was reached on adding any of its functionality;

The TTWG remains open to you (and others) bringing new requirements to the group for consideration; however, at this juncture, it is probably safe to say that DFXP itself is closed for the purpose of considering new requirements unless their absence negatively impacts the basic goals of DFXP.

Regards,

Glenn Adams
Chair TTWG

The response is archived at:

http://lists.w3.org/Archives/Public/public-tt/2006Jul/0012.html

TTWG response agreed by Requestor
None.


Issue 12: Re: Color fidelity during transcoding (hook claiming that there is an accessibility topic)

Comment:

Dear all,

** summary

1) I want to set a hook claiming that there is an accessibility
interest in this topic

... but

2) I think I pretty much come down where Mike Dolan is on the mood of
what DXFP should say (imperative (= normative) vs. informative). DFXP
should include informative mention of accessibility guidelines for
the use of color in captions, and this should be in such a way that
authors of DFXP formatted content *and* those transcoding DFXP into
delivery channels are aware that they have *both, independently* to
pay attention to these guidelines.

** details

3) existence proof for accessibility interest -- WCAG 2.0 guidelines 
Success Criterion 1.4.1

http://www.w3.org/TR/2006/WD-WCAG20-20060427/guidelines.html#visual-audio-contrast

4) DFXP is targeted to be used for captions, that should meet
accessibility guidelines as presented at the final User Interface.

5) Some of the service delivery chains that will use DFXP
representations of timed text are Web delivery chains, including in
the mobile space where we are not so impeded by legacy standards and
channels. W3C takes an interest in providing end-to-end assurances of
interoperability between the people speaking the material that gets
included in captions and the people reading the captions. So at least
for Web use cases, flowing down Human Factors requirements from the
system level to the DXFP document are fair game. Nothing breaks
access faster than long chains of services each of which says it's
"not my problem."

I think that this could be why the Working Group might prefer to duck this
issue, but Cris in his Domain Lead role feels compelled to press the
issue.

* next steps; could we perhaps?:

a) stipulate that DXFP docs will be used a lot to feed service
delivery chains where they don't have a lot of control over the
final color?

b) So shouldn't we warn authors of this?

c) Leave the color rep as is, presuming that this is fine enough, if
faithfully rendered, to meet the great preponderance of fidelity
needs. This format should afford color precision at a level which is
modest overkill for the great preponderance of applications.

d) Warn those who are going to use the color feature in this format
about common system-level risks (illegible color contrasts, lack of
user control, lack of definition in the controlling specs in the last
mile distribution link,...) that bear on this aspect of their content;
along with what known strategies they may wish to apply to mitigate these
risks (pointers to accessibility guidelines, etc.)?

Al
Timed Text WG Response:

Al,

It is not clear from your message below whether you are making a comment on the DFXP 2nd LC text, and if so, if you are expecting a response (since the comment period had lapsed).
In any case, in reviewing the DFXP spec, I see that it does not cite WCAG1.0 in regards to content conformance. However, it does cite UUAG in the context of processor conformance (section 3.2, item 5):

"the processor should satisfy the user agent accessibility guidelines specified by [UAAG]."

I would suggest we resolve this disparity by adding the following sentence at the end of section 3.1, item 5:

"In addition, the infoset should satisfy the web content accessibility guidelines specified by [WCAG]." and add a normative reference to WCAG.

Would this be a satisfactory resolution of your concerns?

Glenn Adams
Chair TTWG

The response is archived at:

http://lists.w3.org/Archives/Public/public-tt/2006Sep/0001.html

TTWG response agreed by Requestor ?
None.


Thierry MICHEL (tmichel@w3.org)

Last Updated:$Date: 2006/11/03 15:38:34 $