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
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
Simple Date/time Events
1. Trigger once on midnight of January 1, 2010
2. Trigger once on 9:00 AM of January 1, 2010
3. On first Monday (w1) after (+) January 1, 2010 (equivalent to January 4, 2010)
4. On last Sunday (w7) before (-) January 1, 2010 (equivalent to December 27, 2009)
Repeated Date/Time Events
5. On the top of every hour starting 9AM on January 1st, 2010
6. On midnight of each of the first 6 Mondays in the year 2010