[linux-dvb] Re: problems with Nova-T card in UK with new DVB driver

[Gregor Lawatscheck <gpel@mpex.net>]

At 10:27 30/04/2003, you wrote:
> >You're using a dxr-3 right? I thought I read a post by someone saying he
> >had the same problem with a dxr-3. Maybe it's av7110 related after all...
>
> I started playing with VDR some time ago, went mad and bought a full feature
> satellite card to do the MPEG decode.  So not a dxr-3 problem.
Sorry, I meant to address this question to Simeon Walker. Good to know 
though, that you have an av7110 Siemens card doing the decoding. I kind of 
think it's related to the code for the av7110 and the one person who had 
problems with a dxr-3 had it because of signal strength problems or something.

> >It's quite freaky that BBC1 *always* works but the other two or three
> >channels on the mux don't. BBC1 has PIDs 600:601, BBC2 610:611, BBC 3 has
> >620:621 and News 24  640:641. It makes no sense to me why BBC1 would work
> >and the others wouldn't.
> >...
>
> That's exactly what I see.
:) In total I've spent around 5-10 hours on and off trying to debug this 
over the past couple of months but couldn't quite figure out what was going 
on. Most people with a DVB-T card using vdr seem to be using a dxr-3 for 
decoding and it appears to be working for them. So there appears to be a 
fairly small field of people who can help trying to track this down.

> Last night I changed my channels.conf to change the Code Rate Low Priority
> from "D12"  to "D0" which seemed to help a bit, though I would have to test
> things over a longer period to be certain.  BBC2 still seemed to have quite a
> few problems though I seemed to be able to switch to BBC3 more reliably!
> BBC1 always works.  Very strange since they are all on the same multiplex.
I've played with mdelay's in av7110 and thought that had made a difference 
but after a while I came to the conclusion I only imagined that. It has 
something to do with the specific data that is sent at the time. It's 
almost like on some scenes or programmes it "tunes" fine most the time, 
while at other times it just won't work at all. It's almost as if it tunes 
better on faster moving scenes or somethting peculiar. Maybe if it doesn't 
get enough specially crafted TS to sync to (maybe with iframes or 
something) in a specific time it fails? Unfortunately I'm not sure exactly 
how the "tuning" or "syncing" process of the av7110 works. vdr seems to 
pass the data to it just fine though... I certainly wonder why and where it 
then goes wrong.

> Changing the Srate from "2700" parameter to "0" didn't make any difference
> (as would be expected since this is for DVB-S and DVB-C).
Yes, unfortunately not. It would have been strange nevertheless as BBC1 
tunes fine with all sorts of strange settings in the "non DVB-T" related 
fields.

- Gregor 


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