[mythtv] NTP config

[Rudy Zijlstra]

Daniel Kristjansson wrote:

>On Thu, 2005-10-20 at 09:57 -0400, Steve Adeff wrote:
>  
>
>>On Thursday 20 October 2005 09:25, Ivor Hewitt wrote:
>>    
>>
>>>Daniel Kristjansson wrote:
>>>      
>>>
>>>>DVB/ATSC time can never be as accurate as ntpd time because the
>>>>transmission, buffering, and capture delays can not be measured.
>>>>But it should always be within a few seconds of the correct time,
>>>>so it is more than good enough for a MythTV backend.
>>>>        
>>>>
>>>Actually you might say for mythbackend purposes it might be more
>>>accurate, since it's the current time that should match the start times
>>>of programs accurately.... even if it is delayed slightly.
>>>      
>>>
>>is this why so many shows don't start "on time"? If the TV stations follow 
>>their own time code then it would make more sense for mythbackend to run on 
>>this time. I guess the only issue is if two stations are running on their 
>>own, differing time...?
>>    
>>
>
>In the US companies using the public airwaves are supposed to use GPS
>to set their clocks, so a program should always start a little late,
>and never early. This regulation doesn't apply to cable, and I don't
>know what the laws are in DVB countries. But this is what pre-roll
>and post-roll are for. If you add 5 seconds on each end you should get
>the entirety of any program when you don't have a recording scheduled
>before or after the program, at that point MythTV ignores the pre-roll
>and post-roll settings on the assumption that you would rather get the
>other program than apply this extra safety buffer.
>
>There is some controversy over whether MythTV should have a pre-roll
>and post-roll which is never ignored. But this is mostly due to
>channels in Australia which don't adhere to their published schedule
>and air programs up to 20 minutes later than scheduled. This would
>be illegal in the other countries unless they transmitted updated
>EIT data or the government activated some sort of emergency broadcast
>override, say in the case of global thermonuclear war.
>
>-- Daniel
>
>  
>
In the Netherlands, Belgium, France, Germany - those i am certain of - 
programs can start more than 20 minutes later than announced. Not on all 
channels, some are worse than others, yet most channels are "late" by 
23:00 or later. Which is why i am using a hard "end-late" setting on all 
recordings, and enough tuners so that recordings do not need to be 
back-to-back on the same tuner.

It does not matter whether the broadcast is analog or digital (DVB), the 
behaviour is the same. And EIT-schedule, even EIT-next/now is not always 
modified....

Cheers,

Rudy