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Re: Need Update to TTML1 Errata

From: Nigel Megitt <nigel.megitt@bbc.co.uk>
Date: Mon, 21 Jul 2014 14:54:39 +0000
To: Glenn Adams <glenn@skynav.com>
CC: TTWG <public-tt@w3.org>
Message-ID: <CFF2E448.2056E%nigel.megitt@bbc.co.uk>
On 17/07/2014 17:18, "Glenn Adams" <glenn@skynav.com<mailto:glenn@skynav.com>> wrote:



On Thu, Jul 17, 2014 at 9:52 AM, Nigel Megitt <nigel.megitt@bbc.co.uk<mailto:nigel.megitt@bbc.co.uk>> wrote:
This is (mostly*) dependent on us closing Issue-259, which is dependent on Pierre's review, as agreed in our meeting this afternoon. Others are at liberty to review and comment too of course.

So we should not put these errata to TR until Issue-259 is closed. When it has been closed I'm happy for these errata to be considered part of the solution to Issue-259 and push through ASAP after that. ASAP here is >= 10 days after resolution of Issue-259 as per our charter.

* By the way I didn't expect the use of zero duration to be permitted via this errata document since it is a substantive change rather than a clarification. Is there a pressing reason why it needs to be in TTML 1 and can't wait until TTML 2?

I don't view it as a substantive change but rather a failure to document expected usage and prior intention. For example, we have:

The Root Temporal Extent, i.e., the time interval over which a Document Instance is active, has an implicit duration that is equal to the implicit duration of the body element of the document, if the body element is present, or zero, if the body element is absent.

... if the anonymous span's parent time container is a sequential time container, then the implicit duration is equivalent to zero

This quote references implied durations not the values permitted on explicitly defined dur attributes.


Further, syntactically, dur was defined to be a <timeExpression> which clearly allows dur="0s".

It's a fine point, but I think one could make an argument that the SMIL semantics add extra constraints to <timeExpression> when used in the context of the dur attribute, under current wording pre-errata.

So we are really just clarifying a pre-existing state: that we allow a duration of value 0.

Okay I'll accept this; I think there may be a valid counter-argument but I'm not going to pursue it any further.

Thanks,

Nigel




Kind regards,

Nigel


On 17/07/2014 16:26, "Glenn Adams" <glenn@skynav.com<mailto:glenn@skynav.com>> wrote:

I have been updating the TTML1 Errata document in the repository [1], and now have three additional items (see those marked as "published 2014-07-17). We need to push these errata through to the TR page [2].

I would like for either (1) Thierry to push these to TR ASAP, or (2) defer the push until we discuss in a teleconference. Nigel, please recommend an approach.

[1] https://dvcs.w3.org/hg/ttml/raw-file/default/ttml1/spec/ttml1-errata.html
[2] http://www.w3.org/2013/09/ttml1-errata.html
Received on Monday, 21 July 2014 14:55:15 UTC

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