View Bug Details

IDProjectCategoryView StatusLast Update
0002300DCP-o-maticFeaturespublic2024-04-23 23:06
Reportercarl Assigned Tocarl  
PriorityhighSeverityminorReproducibilityN/A
Status closedResolutionfixed 
Target Version2.16.36 
Summary0002300: Change how time zones are handled for KDMs
Description

Cinema UTF offsets often change with daylight savings time (at different times in different countries etc.) so having a UTC offset per cinema is awkward. Instead, we should add a UTC control to the KDM time, then use that to fill in KDM timestamps using the -00:00 notation (i.e. time is in UTC and we don't know how that relates to the local time zone).

e.g. if we're in the UK on BST we enter 14:00 to 16:00 and a UTC offset of +2, then the KDMs get written as 12:00-00:00 to 14:00-00.

TagsNo tags attached.
Branch2300-kdm-timing
Estimated weeks required
Estimated work requiredUndecided

Relationships

related to 0002473 resolvedcarl Use sqlite for cinema lists / anything that could be shared 

Activities

carl

2022-11-29 12:39

administrator   ~0005341

See https://www.rfc-editor.org/rfc/rfc3339#page-5 section 4.3

carl

2022-11-29 21:02

administrator   ~0005342

Not sure now of the point of using -00:00...

Say we have some country A which is UTC -04:00 i.e. 14:00 in UTC is 10:00 in country A.

And we're making a KDM for country A. We want to enter the validity time there, not here. DoM can't know what time zone a particular country is in, so we must tell it the time zone.

This is what we tried to do so far with the UTC offset in Cinema. But that doesn't work because UTC offset changes through the year.

Now we're suggesting in the UI, we want the KDM to start at 17:00 local time, so we say

17:00 UTC-4

(i.e. 21:00 UTC) and into the KDM we we write 17:00T-04:00.

Not sure what the benefit is of writing 21:00T-00:00 as this report suggests.

carl

2022-12-03 23:49

administrator   ~0005351

This also feels like quite a big change that should maybe end up in 2.17.x

carl

2022-12-13 20:59

administrator   ~0005361

Running tests of 2300 libdcp branch against DoM, then merge that to libdcp main, then merge this to 2.17.x

carl

2022-12-14 19:37

administrator   ~0005363

a7ba9ea0f6a896821f9c9540fd7bbedfc059cf42 in v2.17.x

carl

2024-04-23 22:10

administrator   ~0006385

Doubts were raised about this: https://dcpomatic.com/forum/viewtopic.php?t=2359

If we have TZ per cinema, and we make KDMs, they will be wrong during DST, and there's not much you can do other than edit the cinema.

If we remove TZ per cinema, and set it during KDM creation, you have to remember the TZ + DST otherwise the KDM timing is more wrong.

So the argument is that we should have TZ per cinema, and also allow it to be edited at creation time - if you forget (or don't know) that the cinema is in DST at least you're only an hour or two out.

carl

2024-04-23 23:06

administrator   ~0006386

The difficult part with that is that we can have multiple cinemas (in different time zones) selected, but only one set of controls for the timing window. I guess in those cases we can disable the time zone modifier.

Bug History

Date Modified Username Field Change
2022-08-17 15:37 carl New Bug
2022-08-17 15:38 carl Assigned To => carl
2022-08-17 15:38 carl Status new => acknowledged
2022-08-28 23:37 carl Target Version 2.16.22 => 2.16.23
2022-09-03 21:03 carl Target Version 2.16.23 => 2.16.24
2022-09-04 13:16 carl Target Version 2.16.24 => 2.16.25
2022-09-11 08:37 carl Target Version 2.16.25 => 2.16.26
2022-09-18 20:55 carl Target Version 2.16.26 => 2.16.27
2022-09-24 21:55 carl Target Version 2.16.27 => 2.16.28
2022-09-28 23:48 carl Priority normal => high
2022-10-05 17:48 carl Target Version 2.16.28 => 2.16.30
2022-10-12 11:53 carl Target Version 2.16.30 => 2.16.31
2022-10-19 19:47 carl Target Version 2.16.31 => 2.16.32
2022-10-26 19:07 carl Target Version 2.16.32 => 2.16.x
2022-11-22 22:48 carl Target Version 2.16.x => 2.16.35
2022-11-22 22:48 carl Estimated work required => Undecided
2022-11-29 09:46 carl Status acknowledged => in progress
2022-11-29 09:46 carl Branch => 2300-kdm-timing
2022-11-29 12:39 carl Note Added: 0005341
2022-11-29 21:02 carl Note Added: 0005342
2022-11-30 21:25 carl Target Version 2.16.35 => 2.16.36
2022-12-03 23:49 carl Note Added: 0005351
2022-12-13 20:59 carl Note Added: 0005361
2022-12-14 19:37 carl Status in progress => resolved
2022-12-14 19:37 carl Resolution open => fixed
2022-12-14 19:37 carl Note Added: 0005363
2023-09-01 21:52 carl Status resolved => closed
2024-04-23 22:10 carl Note Added: 0006385
2024-04-23 22:11 carl Relationship added related to 0002473
2024-04-23 23:06 carl Note Added: 0006386