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Daylight Saving Time (DST) considerations!

Posted: 20 Mar 2016 17:36
by radio42
We will soon have a daylight saving time (DST) change!
E.g. European Summer Time will change on the 27th of March from 02:00 am to 03:00 am.
This means the '2am - 3am hour slot' will effectively be skipped. This also means, that we would have to take care about this fact in your daily scheduling within ProppFrexx ONAIR.
I'll try to summarize what you would have to take care of within your Program Scheduler as well as in your Overlay Scheduler:

1. General Behavior of the Scheduler Component:
By default the scheduler component simply shifts all scheduled entries happening within the DST change time range by 1 hour. For example an entry which was supposed to start at 2am according to the standard time, will now be shifted to start at 3am (an entry which was supposed to start at 2:30am will now be scheduled to start at 3:30am ... etc.). The following picture (with 4 daily recurring entries) will illustrate this as an example:
DST Scheduler Example
DaylightSaving.jpg (55.83 KiB) Viewed 5195 times
As you can see in the picture, the 'Test 2' entry got shifted to 3am. In this particular case there is also another entry scheduled at 3am as well; as such 2 entries are scheduled in parallel at 3am. This would result in a conflict.
As there is logically NO generic way to resolve this conflict, you must resolve it manually!

2. Program Scheduler considerations:
For program scheduler entries the rule within ProppFrexx is, that ONLY one program can be started at any given time!
In the above example, this would mean, that if 2 entries start in parallel, one of them would by default be suppressed. Typically this would effectively be the 'Test 3' entry. As such you should check your program scheduler manually. If needed, remove the respective entry occurrence (select it and press the DEL key; and choose to remove the occurrence and not the entire series).
Why can this not be resolved automatically?
The reason is pretty simple: There might be many scenarios, where nothing needs to be resolved...
E.g. assume, that there is a program 'A' starting at 23pm at the previous day, a program 'B' starting at 2am (at the DST change) and a program 'C' starting at 6am. In this case nothing needs to be adjusted, as the program 'B' will now simply start at 3am instead of 2am - or in other words the duration of the program 'B' will simply run 1 hour less than at other days.

3. Overlay Scheduler considerations:
Overlay scheduler entries are effectively allowed to start in parallel within ProppFrexx.
As the DST time slot being skipped does effectively not exist, we can for overlay entries safely simply remove all occurrences automatically which fall into the DST time slot. E.g. in the above example all entries between 2am and 3am are suppressed automatically.
The reason of this is, that I assume, that you do not want to re-schedule overlays (e.g. adverts) after a DST change for that missing hour.
Thus for the overlay scheduler you typically do not need to do anything extra!

4. DST change back from summer to winter time:
In this case the time changes back from 3am to 2am - thus the hour is repeated.
Form a scheduling point of view you actually do not need to consider anything special. Entries within that entry are simply scheduled twice, but they do typically not result into any conflicts.
E.g. in the above given example, the 2am hour is scheduled at 2am. The 3am entry is also scheduled on time, but then the hour is repeated, so that the 3am program is hour longer in duration.
In case of pre-prepared playlists scheduled at that time, make sure to make the playlist 1 hour longer in duration!

That's it ;-)