[linux-dvb] full featured card without signal and requited video memory investigation

[Gregor Lawatscheck <gpel@mpex.net>]

I'm putting this back on the list as it's interesting:


On Wednesday 09 July 2003 2:52 pm, Gregor Lawatscheck wrote:
[snip]

>> You could still "misuse" a full featured sat or cable card, as is a patch
>> to the current vdr to use it with the 0.9.4 drivers which don't mind a
>> missing sat signal:

Andy replied:

>Mm... maybe I'm misunderstanding something here, but I'm using vdr 1.2.0pre1
>with drivers from around 12.4.03. I have no sat signal or cable to my DVB-s
>and the Nova-t is working fine through it.

>Andy

At 17:35 10/07/2003, I replied:
> > Interesting - frist time I hear this. Do you use vdr? Don't you have
> > problems with the BBC channels - i.e. black screens as pre1 has a 210k
> > video buffer?
>
> It's all working fine here with vdr and is on all the time I'm at home - 
> up to
> 7 days at a stretch I guess sometimes.
That's good news!

> No problems with BBC except when atmospheric pressure is very high and I get
> video and audio break up, but that could be antenna alignment as much as
> anything else - however the driver is patched with the statmux_fix patch -
> yours IIRC.
ahhh I see, cool. statmux_fix for the driver (adapted by Oliver Endriss) or 
in vdr. It shouldn't make a difference, just wondering. Just for the 
record: What we did was setting higher (fixed) bandwidth in the stream 
headers of around 15 mbit despite the real bandwidth. The BBC channels that 
previously didn't decode then worked fine with a 210k video memory.

It looks like the statmux fix(es) correct the 210k issue video memory stuff 
just fine - wow that's good news. It still crashed here after a couple of 
hours andI blamed it on our statmux fix. As it seems now it was the missing 
sat signal here, not the patch...  Thanks to Klaus we're up to 230k video 
memory as of pre3, , which solved the problem without a patch. Nevertheless 
this something to keep in mind for the future if there's deperate need for 
free memory in the firmware.

Either your revision of the card makes a difference or you're in the lucky 
position that somehow vdr or the driver just never touches the tuning part 
of the dvb-s.

What revision is you full dvb-s card? I've got a 1.3 here. Which version of 
vdr are you using? How's your EPG setup for vdr - standard or altered so it 
doesn't scan at night?

I've recently moved back to Berlin and my vdr box is currently disassembled 
so I can't test with pre1 myself at the moment. If you feel like testing, 
it'd be interesting to see what happens if you use pre3. I remember without 
a sat signal the driver would suck up to 40% CPU when it tunes to it. I'm 
guessing the EPG or something tries to tune to the SAT at night and then 
you end up with a high load.

- Gregor         


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