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Re: ISSUE-151 Clarify syncbase in SMPTE continuous mode - Draft Change Applied

From: Andreas Tai <tai@irt.de>
Date: Mon, 28 May 2012 15:35:07 +0200
Message-ID: <4FC37F0B.1010809@irt.de>
To: public-tt <public-tt@w3.org>, Glenn Adams <glenn@skynav.com>
Thanks, Glenn for clarification. That´s the same how I understand it.

I would therefore propose the following change in chapter 10.4 Time 
Intervals:

=> 4th bullet point

Now:
"If the governing time mode is media or smpte with mode continuous, then 
time expressions must be interpreted as equivalent to offset based 
timing in [SMIL 2.1], namely, as offsets from an implicit syncbase."

Change Proposal:
"If the governing time mode is media, then time expressions must be 
interpreted as equivalent to offset based timing in [SMIL 2.1], namely, 
as offsets from an implicit syncbase."

Best regards,

Andreas

Am 27.05.2012 19:53, schrieb Glenn Adams:
>
> On Sun, May 27, 2012 at 6:10 AM, Andreas Tai <tai@irt.de 
> <mailto:tai@irt.de>> wrote:
>
>     The edit of ttp:markerMode with the value "continuous" implies
>     that all time expression in markerMode "continuous" are "labeled
>     synchronization events (markers)".
>
>     I have two questions with the reference to the last example on the
>     discussion page on issue 151
>     (http://www.w3.org/wiki/TTML/Issue151Discussion):
>
>     <p region='r' begin='00:00:27:00' end='00:00:38:00'>
>     <span begin='00:00:28:00'>A</span>
>     <span begin='00:00:29:00'>B</span>
>     <span begin='00:00:30:00'>C</span>
>     </p>
>
>     Assumption: timebase = "smpte" + markerMode = "continuous"
>
>     1) Are the time expressions of the span elements valid?
>
>
> yes
>
>     2) Is the begin of the first span element timed when some external
>     synchronization context emits the event "00:00:28:00" or is it
>     timed 28s after the begin of the parent p (so at "00:00:55:00")?
>
>
> the former, since, by default, all TTML elements are parallel time 
> containers; the more interesting question is whether it is valid to 
> specify the use of a sequential time container when timeBase is smpte; 
> at present, i don't think we have any language that covers this case
>
> if we do allow sequential time containment for smpte time base, then 
> it would be possible to interpret "00:00:28:00" as a relative time (as 
> opposed to absolute marker) only in the case that markerMode is 
> continuous, since it is feasible to convert relative smpte time 
> coordinate expressions to media time deltas (i.e., offset time) in 
> continuous mode (even in the case of drop frame)
>
>     Thanks and best regards,
>
>     Andreas
>
>     Am 26.04.2012 06 <tel:26.04.2012%2006>:31, schrieb Glenn Adams:
>
>
>         I've taken a stab at addressing ISSUE-151 [1] (ACTION-51 [2]).
>         See updated ED [3] and changeset [4].
>
>         The relevant changes are under Sections 6.2.11 (ttp:timeBase)
>         and 6.2.6 (ttp:markerMode).
>
>         [1] http://www.w3.org/AudioVideo/TT/tracker/issues/151
>         [2] http://www.w3.org/AudioVideo/TT/tracker/actions/51
>         [3]
>         http://dvcs.w3.org/hg/ttml/raw-file/tip/ttml10/spec/ttaf1-dfxp.html
>         [4] http://dvcs.w3.org/hg/ttml/rev/2bde2e2c5507
>
>
>
>     -- 
>     ------------------------------------------------
>     Andreas Tai
>     Production Systems Television IRT - Institut fuer Rundfunktechnik GmbH
>     R&D Institute of ARD, ZDF, DRadio, ORF and SRG/SSR
>     Floriansmuehlstrasse 60, D-80939 Munich, Germany
>
>     Phone: +49 89 32399-389 <tel:%2B49%2089%2032399-389> | Fax: +49 89
>     32399-200 <tel:%2B49%2089%2032399-200>
>     http: www.irt.de <http://www.irt.de> | Email: tai@irt.de
>     <mailto:tai@irt.de>
>     ------------------------------------------------
>
>     registration court&   managing director:
>     Munich Commercial, RegNo. B 5191
>     Dr. Klaus Illgner-Fehns
>     ------------------------------------------------
>
>


-- 
------------------------------------------------
Andreas Tai
Production Systems Television IRT - Institut fuer Rundfunktechnik GmbH
R&D Institute of ARD, ZDF, DRadio, ORF and SRG/SSR
Floriansmuehlstrasse 60, D-80939 Munich, Germany

Phone: +49 89 32399-389 | Fax: +49 89 32399-200
http: www.irt.de | Email: tai@irt.de
------------------------------------------------

registration court&   managing director:
Munich Commercial, RegNo. B 5191
Dr. Klaus Illgner-Fehns
------------------------------------------------
Received on Monday, 28 May 2012 14:20:37 UTC

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