How does TV put the clocks back?

[Brekkie]

Just wondering...

Been a bit of talk over the last few days about the technical elements of things like the news channels keeping to time and just wondering how seemless the clock changes are for broadcasters - or does it take a bit of human intervention to ensure they don't fall off air?

[technologist]

In the NTSC ATSC works you have to jam sync your time of day code every day …as there is not an integral number of frames per second minute or hour … one of the “joys” of fractional frame rate
So you may start the day without the daylight saving offset you should have
rather than changing it an hour or two later

In a 50 Hz world time if day code needs to be reset around the time daylight saving comes on or off ,
And thus is usually done by agreement when no one is using it rather than when time changes.
Just preset it …

Playout systems should work by UTC and MJD ….. so it’s only the output screens and displays
where a local time matters,
That Usually happens very close and just after the change and can be set by receiving the change from another off air GNSS or similar system
… or by programming the system to do it at UTC = 01:00:xx:yy or whatever locally on a particular MJD .

But sometimes it easier for MCR or whatever to do it manually

Most systems actually have counts from the start of epoch rather than UTC and MJD …
Or a sample rate clock …….
And if course in ST2110 PTP determines when a frame starts And sample rate when it ends . ….

But if course remotes/OBS need to switch around the same time as their destination studio. …
Others may like to comment !1

[Inspector Sands]

It's probably not too much of a problem for most news channels as they work in hours blocks and if anything runs over the clock change itself its live. In the autumn they'll just produce another running order for the second 1am to 2am hour.

International news channels don't have to worry about it at all except for schedule changes to accommodate programmes going out in certain areas. The change to the US time zones isn't the same as Europe's which means those booking guests and facilities in the US have to get their head three time changes in a month*.

Regular channels handle the clock change easier now than they used to, the playout systems cope better. When I worked in BBC playout many years ago they always scheduled films across the clock change and the durations tweaked accordingly - so a film that was 90 mins long was scheduled for 150 minutes in the autumn and vice versa in the spring - 30 mins. Then the schedule was put on Hold over the actual change so it wouldn't move on to the next item if it got confused.


* for example imagine someone working on a news programme that goes out at 1800 GMT and they're based in London. They'll be used to booking local guests for 1900 and guests in New York at 1400. Then the clocks go back in the US so they have to ask a guest in New York to turn up for 1300 but the guest in London still for 1900. Then at the end of October it changes again and the London guest needs to turn up at 1800 local.

Also to really confuse the person doing the bookings, they'll probably be starting and finishing work an hour earlier too

[Transmission]

With playout, the clock change doesn't affect the automation itself which runs in GMT in the background but you do have to wait for the engineers to do their rounds and fix how things look on the editors and the clocks on the multiviewers etc.

The schedules for the Saturday are always delivered as 23 or 25 hours, depending on which way the clocks are changing.

And of course you always have to watch out for any lines bookings which might have been made in GMT rather than local time, as well as making sure that schedulers haven't made any mistakes with live events. Easily done!

[valley]

The only thing I notice is the good old EPGs going a bit haywire. For example, today's Sky schedule has an un-labeled hour at the end of the day as the hour markers aren't shifted correctly.

https://www.sky.com/tv-guide/20211031/4101-1/501

[Gusan]

The BITO does it by TTK in sync with the CST with the aid of ESC

[Markymark]

With playout, the clock change doesn't affect the automation itself which runs in GMT in the background but you do have to wait for the engineers to do their rounds and fix how things look on the editors and the clocks on the multiviewers etc.

The schedules for the Saturday are always delivered as 23 or 25 hours, depending on which way the clocks are changing.

And of course you always have to watch out for any lines bookings which might have been made in GMT rather than local time, as well as making sure that schedulers haven't made any mistakes with live events. Easily done!

Apparently C4's first clock change (March 1983) after they launched shut the channel down.

They were due to close-down at 01:30 GMT. At 01:00 hrs the station's time reference taken from MSF jumped forward an hour to BST. The automation system detected it was suddenly 02:00 hrs, and promptly cut to black and tone.

[Brekkie]

Wasn't there something similar more recently where a live event got thrown off air due to a GMT/BST mix up ending the feed an hour early?

[Josh]

Don't think this is what you're thinking of but it fits the criteria:
https://www.youtube.com/watch?v=dAqJS1nAKYA

[dafydd]

The only thing I notice is the good old EPGs going a bit haywire. For example, today's Sky schedule has an un-labeled hour at the end of the day as the hour markers aren't shifted correctly.

https://www.sky.com/tv-guide/20211031/4101-1/501

It looks like the time on Sky's EPG hasn't gone back an hour for some boxes as well. The 5pm news is currently showing as 6pm.

[VMPhil]

Don't think this is what you're thinking of but it fits the criteria:
https://www.youtube.com/watch?v=dAqJS1nAKYA

"Nothing to do with the clocks going forward, I'm pleased to say"

I don't believe you, Mr Continuity Announcer.

[IanJRedman]

The only thing I notice is the good old EPGs going a bit haywire. For example, today's Sky schedule has an un-labeled hour at the end of the day as the hour markers aren't shifted correctly.

https://www.sky.com/tv-guide/20211031/4101-1/501

It looks like the time on Sky's EPG hasn't gone back an hour for some boxes as well. The 5pm news is currently showing as 6pm.

Yes, anecdotally, some Sky+ HD boxes failed to go back an hour this morning, so the EPG is out of kilter. Sky Q and Sky Glass are OK.

[Neil Jones]

The only thing I notice is the good old EPGs going a bit haywire. For example, today's Sky schedule has an un-labeled hour at the end of the day as the hour markers aren't shifted correctly.

https://www.sky.com/tv-guide/20211031/4101-1/501

It looks like the time on Sky's EPG hasn't gone back an hour for some boxes as well. The 5pm news is currently showing as 6pm.

Yes, anecdotally, some Sky+ HD boxes failed to go back an hour this morning, so the EPG is out of kilter. Sky Q and Sky Glass are OK.

There's are two 20 page threads about this on the Sky help forum and the usual complaints of "I pay a fortune, they can't get the basics right, give me my money back". and a level of discussion that seems to suggest the satellites have fallen out the sky.

The online Sky EPG TV Guide is an hour ahead as well (across the top), which seems to suggest something somewhere hasn't noticed the time zone change. The programme data has the right timezone though.

[AaronLancs]

Weren't there vagaries in how BBC News 24 used to do it? I seem to remember at 01:00 BST the clock used to disappear and not reappear until 02:00 BST / 01:00 GMT. This was prevalent during the 1999-2003 era most.

[Brekkie]

P.S. Is the forum clock out for everyone too?