[mythtv-users] NTP drift...

Michael T. Dean mtdean at thirdcontact.com
Wed Oct 11 23:02:40 UTC 2006


On 10/11/06 16:53, John Brooks wrote:

> Hey, all. I noticed that, while my ntp-server service seems to be 
> doing its job for the most part, my clock seems to be about 51 seconds 
> (a not insignificant piece of time for recording) off from the comcast 
> time.

The time one of my local HDTV stations broadcasts in its signal is >10 
minutes ahead the current time.  It wouldn't surprise me if Comcast's 
time is off.  And, remember, Comcast has a lot of "times":  the time on 
the "What's on now" channel, the time embedded in digital broadcast 
signal(s), the time it takes to encode a local SDTV channel for 
retransmission, the time it uses to schedule broadcasts.  Some of these 
are irrelevant, while others may impact the way you schedule recordings.

> More confusingly, my shows seem to be starting earlier than when I 
> begin recording, so I'm not sure *what* end of things to examine. Any 
> thoughts? 


So, you're saying that you schedule a recording at 8:00pm and when you 
later watch it, you find out that the program began before the recording 
started?  This isn't all that uncommon, but usually it's just a couple 
of seconds (which, depending on the situation may be exacerbated by the 
capture card startup and/or tuning time).  You can adjust for it through 
MythTV's start early and end late settings in the recording rule.

Given a specific, detailed example of the problem this is causing, it 
would be much easier to give useful usage advice.

Mike


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