Clock-time form time expressions allow 60 seconds for media timebase.

[nigelmegitt]

There appears to be no restriction on the use of a value of 60 in the seconds component of a clock-time time expression of the form hh:mm:ss. When using ttp:timeBase="media" it therefore appears that a minute can have 61 seconds; my understanding of the use case for this is to accommodate UTC leap seconds, so I would expect a restriction that the 60 seconds value can only apply when ttp:timeBase="clock", and possibly additionally when ttp:clockMode="utc"|"local" since GPS clocks are not adjusted for leap seconds.

[skynavga]

That seems reasonable, but would have to be a note of disrecommendation in
TTML1; we can make normative in TTML2.

On Wed, Apr 20, 2016 at 5:26 AM, Nigel Megitt notifications@github.com
wrote:

There appears to be no restriction on the use of a value of 60 in the
seconds component of a clock-time time expression of the form hh:mm:ss.
When using ttp:timeBase="media" it therefore appears that a minute can
have 61 seconds; my understanding of the use case for this is to
accommodate UTC leap seconds, so I would expect a restriction that the 60
seconds value can only apply when ttp:timeBase="clock", and possibly
additionally when ttp:clockMode="utc"|"local" since GPS clocks are not
adjusted for leap seconds.

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#210

[nigelmegitt]

That works for me.

[nigelmegitt]

I have created a matching issue on TTLM2 : issue 158.

[css-meeting-bot]

The Working Group just discussed Clock-time form time expressions allow 60 seconds for media timebase. #210.

The full IRC log of that discussion

<nigel> Topic: Clock-time form time expressions allow 60 seconds for media timebase. #210
<nigel> github: https://github.com//issues/210
<nigel> Pierre: As per pull request #283 I will propose a similar solution.
<nigel> github, end topic