[vdr] Re: replay stuttering (was: FF card A/V sync - in progress?)

Kartsa kari at kniivila.com
Mon Jan 22 12:53:32 CET 2007


> 
> Kartsa wrote:
> > I've tested the new fw also and no sync problems has occurred.
> > 
> > Although I was hoping that this would have corrected my 
> stuttering problem
> > also. Every now and then replayed video stops for a second 
> or so and begins
> > stuttering for some seconds and then continues normally. 
> With earlier fw it
> > usually caused A/V sync problem but now syncing is fine. This is not
> > repeatable meaning that the problem does not occur if I 
> rewind (or jump) and
> > replay the same moment. Some time ago I had a PIII 550MHz 
> system and in it
> > the stuttering could continue indefinitely (or in the end 
> of the recording
> > :). After an upgrade of hw (new mb and amd 3000+ sempron) 
> the stuttering
> > lasts only a few seconds.
> 
> >From the symptoms you describe it seems very likely that your system
> has a bottleneck between VDR and the data.
> 
> Is your VDR reading from local disks or via NFS?
> Are other things running on your machine that could make your 
> disks busy?
> Do you have DMA enabled on your disks?

VDR is reading from local disks which are SATA disks (on my old hw SATA was
on a PCI card and on new its on mb). VDR is the only thing running that
should cause any disk activity (besides normal sytem prosesses and sshd) and
the system is running on a different disk which resides in PATA channel. I
have to check whether or not I've got DMA enabled.

> 
> 
> BTW: I am also experiencing the same problems every now and then.
> I have S.M.A.R.T. enabled on all my disks and I am wondering if
> these "hickups" come from automatic self diagnostics?

I've got S.M.A.R.T. also enabled. But I doubt that it should make this big
impact. I've tested recording from 9 channels at the same time and having a
recording replaying with no stuttering but I did not make a long test. Maybe
I should. The funny thing is that I made the test with my older hw :)

> 
> Maybe larger replay buffers in VDR would help?
> 
> I am _assuming_ that this line
> 
> #define PLAYERBUFSIZE  MEGABYTE(1)
> 
> in dvbplayer.c defines the buffer size?
> Klaus, can you confirm this?
> 
> Kartsa, since the problem occurs quite often in your setup:
> Could you try to change the above line to
> 
> #define PLAYERBUFSIZE  MEGABYTE(64)
> 
> and let us know if the problem still occurs?

I have a yum installed environment, that is I have not compiled vdr my self.
I do have another machine on which I could do the compilation but it has a
different version of VDR :/ I would be forced to either create the same
environment on my test machine for compilation or update all my vdr related
sw on my vdr box. Maybe I could do the first one. This will take some days
to get done and verified the effect.

\\Kartsa




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