[linux-dvb] Re: A/V dropouts when switching section filters

[Klaus Schmidinger <Klaus.Schmidinger@cadsoft.de>]

Johannes Stezenbach wrote:
> 
> Hello Klaus,
> 
> Klaus Schmidinger wrote:
> [about dvb-kernel 2.4]
> >
> > - When VDR manipulates section filters, sometimes the A/V data stream blacks out.
> >   Most of the time the picture returns after a short while, but sometimes it
> >   doesn't.
> 
> Could you describe this in more detail? So that when I try to
> reproduce it I will know what to look for?
> - how long does it block out?

Sometimes just a split second, sometimes several seconds.
And the worst case is a complete system lockup.

> - when? once after zapping or more often?

More often, at random intervalls (varying from a few seconds to
several minutes in distance). It also would appear that the RTL
channels are less likely to show this than the Pro7 channels,
for instance.

> - does it depend on VDR version or settings?

I only tried VDR version 1.3.12. Since this one works fine with the
DVB driver, I assume the problem is most likely in dvb-kernel.
Hermann Gausterer's post just a few minutes ago would also indicate
that the problem is not VDR dependent.

> - does it happen only in multi-card setups (i.e. with transfer mode)?

No, it also happens with a single (full featured) card.
I just did the "Transfer Mode" test to make sure the data comes from
a budget card and we can safely rule out any firmware problems.

> > - If I disable the StartSectionHandler() call in VDR's cDvbDevice::cDvbDevice(),
> >   the problem does not occur, so I guess it must have to do with section
> >   filtering.
> >
> > - In order to rule out a firmware or AV7110 problem I have set up my
> >   channels so that the actual signal is always taken from my second
> >   DVB card, which is a WinTV NOVA-S (a budget card), and is displayed
> >   on the primary device via "Transfer Mode". It makes no difference
> >   whether I do it this way or watch live tv directly on the primary
> >   (full featured Siemens Rev. 1.3) card.
> 
> That would mean the av7110 does only PES playback, and is
> otherwise not touched?

Right. I even took care that there is no section handling on the
primary card in this case, just to rule that out.

> > Since the same version of VDR worked just fine with the old DVB driver
> > version, I assume there is something seriously wrong in the dvb-kernel
> > version (at least in the 2.4 branch).
> >
> > Unfortunately I don't have the time to dig deeper into this right now,
> > so I was wondering if anybody else is able to reproduce this and maybe
> > find out what's wrong.
> >
> > Meanwhile I'm back to the (good ;-) old DVB driver...
> 
> Well, problems are best solved if the people who have the problem
> work together with the people who attempt to solve it.

Sure - all I meant was that I currently don't have the time to look
into this further myself ;-)
If there are any additional tests I could run, or any further
information you might need, please let me know.

Meanwhile I have applied the patch to dvb_frontend.c that Wolfgang Fritz
has just reminded you to apply to the 2.4 branch, but that didn't change
anything regarding the A/V blackouts.

Klaus