AW: [vdr] Problem with audio sync in playback - maybe caused by ntpd stepping local clock?

martin martin at air-maxx.net
Fri Oct 20 12:58:10 CEST 2006


Well, for Germany ntp1.ptb.de and ntp2.ptb.de are _the_ official sources.
I'm pretty sure you've heard about DCF77 - it's the same signal, but via
LongWave Radio.

Ref: http://www.ptb.de/de/org/q/q4/q42/ntp/ntp_main.htm

I am not sure about, how actually the time is set via VDR. Maybe Klaus can
give us a hint.
I've a DSL-flat and PTB is the source, so all the TV stations can only
derive theire time from there. So if you think that a Satellite is 36.000km
away from us, the signal takes some reasonable time to arrive at your
Sat-dish. 2*36Tkm / 300Tkm/s  =  0.24s :-)

Regards,
Martin


-----Ursprüngliche Nachricht-----
Von: vdr-bounces at linuxtv.org [mailto:vdr-bounces at linuxtv.org] Im Auftrag von
Bernd Juraschek
Gesendet: Dienstag, 17. Oktober 2006 20:39
An: VDR Mailing List
Betreff: Re: [vdr] Problem with audio sync in playback - maybe caused by
ntpd stepping local clock?

On Tue, Oct 17, 2006 at 12:51:33AM +0200, martin wrote:
> Not sure, if this may relate to your problem, but ..
> 
> I use xine plugin and every once in a while I had a short interruption of
> sound. Today I was tail-ing -f syslog for another reason and there was
this
> little glitch again! Just a very short interruption with no sound. I spent
> several weekends to find out, why xine always tells me, that "fixing sound
> card drift". I was p***ed by my hardware, but now I found out, what cause
> the problem. It's my ntpd, that steps the clock on my VDR hardware. To fix
> this, I now start ntpd with the "-x" option.
> 
> For Reference from man ntpd:
> -x     Ordinarily,  if  the time is to be adjusted more than 128 ms, it
>               is stepped, not gradually slewed.  This option forces  the
> time
>               to be slewed in all cases.

Hmm - I've configured VDR to adjust the system time. Possibly this is
causing the
same problem. Should VDR doing the same as "ntpd -x"?

Greetings,
Bernd

_______________________________________________
vdr mailing list
vdr at linuxtv.org
http://www.linuxtv.org/cgi-bin/mailman/listinfo/vdr




More information about the vdr mailing list