[mythtv] Failed DVB recording

Tom Hughes tom at compton.nu
Sat Feb 12 13:00:50 UTC 2005

In message <1108174256.420d65b0717f1 at www.digitalregime.com>
          Taylor Jacob <rtjacob at earthlink.net> wrote:

> Quoting Tom Hughes <tom at compton.nu>:
> > > > 2005-02-09 18:30:04.271 DVB#0 DVB signal 5300 | snr 5000 | ber 143af12 |
> > unc
> > OK. I've worked out how to do this now by tuning with tzap and then
> > using dvbsnoop to look for the PMT data. They are coming in about
> > every 0.19 seconds most of the time - one or are longer but the longest
> > that I've seen is about 0.35 or so.
> OK then timing is not an issue there..
> If I remember right you posted something else that showed a very low signal
> 5000s or so both for signal and more imporantly SNR.. Is this a typical
> value for you?  Do you ever have reception issues?  I am wondering if you
> just have a bad signal or if its possible you had some signal fade when
> this recording was attempted..

My reception is brilliant - one of the multiplexes is particularly
bad but the other five are normally alright. The odd glitch in the
picture but nothing major.

I'm not entirely convinced that the Visionplus cards I'm using report
the error statistics correctly. A friend has a Nova-T and a Visionplus
and gets very different numbers from them for signal quality etc.

As I said in my other followup, it looks like the problem might be
related to the system being particularly busy. I had a subsequent
occurrence where both tuners failed to tune when the backend was
restarted but the CPU was fairly busy at the time, and the disk was
also rather busy so maybe there is some sort of PCI latency issue
that delays data reaching the processor.

> We also still plan on dealing with Signal Loss and Off Air channels is a
> much more elegant way that will not result in timeouts like this (assuming
> there isn't really a problem with the code and it will get a PMT
> eventually).  We could then flag the recording as questionable, but the
> signal handling code isn't implimented yet..

Sounds good.


Tom Hughes (tom at compton.nu)

More information about the mythtv-dev mailing list