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

martin martin at air-maxx.net
Tue Oct 17 00:51:33 CEST 2006


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.

Regards,
Martin

-----Ursprüngliche Nachricht-----
Von: vdr-bounces at linuxtv.org [mailto:vdr-bounces at linuxtv.org] Im Auftrag von
C.Y.M
Gesendet: Montag, 16. Oktober 2006 16:39
An: VDR Mailing List
Betreff: Re: [vdr] Problem with audio sync in playback

Tero Siironen wrote:
> On 14.10.2006 23.20, "Pasi Juppo" <pasi.juppo at iki.fi> wrote:
> 
>> This problem is yet to be fixed to my understanding. Now I have a good
>> recording (one episode from Lost) where this happens very often. The
>> problem seems to be related to situations where the scene fades black
>> before new scene. There is something strange in those situations..
>>
>> If someone has the knowledge/talent to start debugging the problem I can
>> put the recording available for downloading.
> 
> Well, I don't have knowledge for debugging, but I ran some tests. I took
few
> minutes crop from a recording of same episodes and tried it with different
> AV7110 firmwares. (TT DVB-C FF 2.1 card)
> 
> I tested with VDR 1.4.3 and test_av app included in 22623 test firmware
> package, with firmwares 261a, 261f, 2622 and that test version 22623.
> Everytime playback stuttered and lost a/v sync after scene change
situation.
> 
> So I think this is more like dvb firmware/driver problem than VDR problem.
> However this is very annoying.
> 
> 

The only way i know how to fix that is to run your FF card with some kind of
software playback (ie; xine).  I wish we had a version of firmware that
didn't
have this problem.. or at least a way for it to recover itself.

Regards.

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