[mythtv] backend crash on dvb channel change, backtrace included

[Brian May]

>>>>> "Juha" == Juha Pahkala <juhis at trinity.is-a-geek.com> writes:

    Juha> I'm experiencing a mythbackend crash when changing
    Juha> channels. I've tried several cvs snapshots recently, and
    Juha> this bug seems to affect them all. I have a DVB setup with
    Juha> one capture card. It's around 90% reproducable when changing
    Juha> to one particular channel, channel #3 (MTV3 in HTV cable
    Juha> network in Helsinki). With other channels, I'm not sure if
    Juha> I've ever seen it.

    Juha> The DVB setup, including this particular channel, is know to
    Juha> work using eg. mplayer. But it's really strange it seems to
    Juha> be only this one channel that mythtv is having difficulties
    Juha> with. Attached is a backtrace of the situation, if someone
    Juha> with a little bit of understanding of mythtv could take a
    Juha> look at it and see what's going on, I'd be really
    Juha> grateful. Also, It'd be interesting to know if anybody else
    Juha> has a setup that is succesfully working here in Helsinki
    Juha> with 'MTV3' the channel I'm having trouble with.

I too have had crashes when changing channels with DVB. However, tzap
worked fine, every time.

Not sure about mplayer, it suddenly stopped working altogether (came
up with the same error message every time), and I had to reboot to get
things going again. IIRC, when mplayer died, tzap also died, but I am
not 100% certain.

I get the impression I may be dealing with multiple problems here, it
doesn't make it easy to debug. Some problems are specific to the
PVR350 input, and other problems are specific to Nova-T input.

I have a suspicion that all above problems may be linked to low signal
quality, but this doesn't make sense because tzap seems to be
reporting high signal strength (interference?).

Crashes come in different forms, eg.
- picture stops, and front end has to be started.
- as above, DVB card dies and computer has to be rebooted.
- once all sound in DVB shows was stuttering, and I had to reboot to fix.
- HDTV sound always stutters, and is unusable.
- sometimes mythtv has recorded show on wrong channel.
- most extreme crashes cause the backend to die.
- when running out of disk space, mythtv kept trying to record
regardless.  I had to free the disk space and restart the backend (to
force it to create new files from scratch). I thought mythtv would
stop recording when free space was less then the configured 300Meg,
but I might be confused. Also some error indication from the frontend
would be nice...

What version of the DVB drivers should I be using (Nova-T card)? I
tried linuxtv-dvb-1.1.1, but channel changing wouldn't work at all on
mythtv (0.14), so I downgraded to linuxtv-dvb-1.1.0. Since then I have
upgraded to mythtv CVS, should I also upgrade the DVB drivers again?

As much as I like MythTV, I need to improve somewhat on reliability;
it kind of defeats the purpose if I have to setup my VCR to record
shows at the same time because I don't entirely trust MythTV to do it
properly.
-- 
Brian May <bam at snoopy.apana.org.au>