Wallclock

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The wallclock module of SMIL supports using ISO-8601 date/time specification as part of its event triggers.

For digital signage, wallclock is a crucial component that allows precise scheduling of media playback.

Wallclock provides an absolute and precise synchronization mechanism. While one may specify time offset values in the dur and begin attributes, such offsets are relative and errors easily accumulate to prevent using time offsets as a precise synchronization mechanism.

Due to its absolute timing, elements using wallclock events must be direct children of <par> and <excl> playlists.

Contents

Simple Date/time Events

1. Trigger once on midnight of January 1, 2010

2010-01-01

2. Trigger once on 9:00 AM of January 1, 2010

2010-01-01T09:00:00.000

Day-of-Week Events

3. On first Monday (w1) after (+) January 1, 2010 (equivalent to January 4, 2010)

2010-01-01+w1

4. On last Sunday (w7) before (-) January 1, 2010 (equivalent to December 27, 2009)

2010-01-01-w7

Repeated Date/Time Events

5. On the top of every hour starting 9AM on January 1st, 2010

R/2010-01-01T09:00/PT1H

6. On midnight of each of the first 6 Mondays in the year 2010

R6/2010-01-01+w1/P1W

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