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Re: DFXP 1.0 Last Call issues list

From: Silvia Pfeiffer <silviapfeiffer1@gmail.com>
Date: Sat, 12 Sep 2009 17:31:57 +1000
Message-ID: <2c0e02830909120031h4bcb9358t337fb4235365bd29@mail.gmail.com>
To: Glenn Adams <gadams@xfsi.com>
Cc: Philippe Le Hegaret <plh@w3.org>, public-tt@w3.org, daniel.weck@gmail.com, werner.bailer@joanneum.at, Gur@captionsinc.com
On Sat, Sep 12, 2009 at 4:53 PM, Glenn Adams <gadams@xfsi.com> wrote:

> inline below ([GA])
> On Sat, Sep 12, 2009 at 1:06 AM, Silvia Pfeiffer <
> silviapfeiffer1@gmail.com> wrote:
>> Hi all,
>> Most of my feedback has been addressed.
>> Here is a short list of things that I think can still be improved.
>> However, I do not think any of this should stand in the way of moving the
>> specification to CR.
>> 1. ttp:clockMode
>> There is still no example on what a specification that uses gps, utc and
>> local values would look like.
>> I am particularly worreid about the GPS time coordinates, for which the
>> format is not defined anywhere - not even in the given reference for GPS -
>> only when I do a bit of a search, I find
>> http://tycho.usno.navy.mil/usno_head.html , but that format seems not to
>> fit with the rough description given in DFXP as:
>> "The primary difference between GPS time and UTC time is that GPS time is
>> not adjusted for leap seconds, while UTC time is adjusted as follows: UTC =
>> TAI (*Temp Atomique International*) + *leap seconds accumulated since
>> 1972*. TAI is maintained by the *Bureau International des Poids et
>> Mesures* (BIPM) in Sevres, France. The GPS system time is steered to a
>> Master Clock (MC) at the US Naval Observatory which is kept within a close
>> but unspecified tolerance of TAI."
>> Maybe it makes sense to remove the gps specification, since it's not
>> expected to be substantially different to UTC and since not specifying the
>> format properly will mean we won't get interoperable implementations of this
>> feature. However, I am not too fussed about leaving it in - it just won't
>> get used then.
> [GA] GPS based time codes are used in US DTV broadcasts for PSIP, which is
> the format of transmitting program event (i.e., EPG) related data; the
> normative reference to the US Navy Observatory site is sufficient for anyone
> to ascertain the differences between UTC and GPS time codes;
> since most of the world's aviation and naval industry is satisfied with the
> definition of GPS time codes, you should be as well, and I leave it to you
> (the reader) to research yourself sufficiently the difference between the
> two, which is well captured by the description given in DFXP;

I spent half an hour searching for it and I am still unclear what the actual
*format* should look like. If it is so clear to you, why not add a simple
one-line example?

The Web world is what I am concerned about, not the aviation and naval
industry and most of the Web world will not have seen a standard GPS
timecode format.

> 2. Other requested examples as per
>> http://www.w3.org/2009/09/dfxp-lc-issues.html
>>  and
>> http://lists.w3.org/Archives/Public/public-tt/2009Jun/0020.html
>> would be helpful to add, but are not urgent, since they don't
>> fundamentally change the spec.
> [GA] I agree it may be helpful, but it is strictly informative, so is not
> strictly necessary. Furthermore, nobody is volunteering to create these
> examples (are you?).

I would if I even knew for most of these things what an example would look
like. I am asking for these examples because they would clarify the spec.

>  3. Section ordering
>> http://lists.w3.org/Archives/Public/public-tt/2009Jun/0028.html
>> I am not overly fussed about, though I think the concrete suggestions I
>> made would be trivial to execute and would improve the readability.
> [GA] I'm afraid you underestimate the editorial work involved to do this
> reordering, and it adds nothing to the technical content of the document.

Moving a section is not difficult. I have edited other W3C drafts and I know
what's involved.

>  4. Use of external metadata
>> http://lists.w3.org/Archives/Public/public-tt/2009Jun/0034.html
>> I may be blind, but I cannot see an example of foreign namespace metadata
>> from Dublin Core added in 12.1.1 of http://www.w3.org/TR/ttaf1-dfxp/, see
>> ISSUE-137.
> [GA] You are looking at the wrong version of DFXP. Look at at the current
> editor's update at:
> http://dev.w3.org/2008/tt/spec/ttaf1-dfxp.html#metadata-vocabulary-metadata
> look specifically at the last example in 12.1.1 "Example Fragment - Foreign
> Element Metadata".

Excellent - I thought that might be the case. That example clarifies a lot.
Thanks for the link.

Best Regards,
Received on Saturday, 12 September 2009 07:33:04 UTC

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